Obstetrics & Gynecology Diagnostic Medical Sonography (Diagnostic Medical Sonography Series) [4 ed.] 1496385519, 9781496385512

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DIAGNOSTIC MEDICAL SONOGRAPHY

Obstetrics and Gynecology

DIAGNOSTIC MEDICAL SONOGRAPHY

Obstetrics and Gynecology FOURTH EDITION

Susan R. Stephenson,

MS, MAEd, ROMS, RVT, CliP

Siemens Medical Solutions USA, Inc. Salt Lake City, Utah

Julia Dmitrieva,

DBA, ROMS (OB)(AB)(BR), ROCS, RVT

Philips Healthcare Bothell, Washington

• ®Wolters Kluwer Philadelphia • Baltimore • New York ·• London Buenos Aires • Hong Kong • Sydney • Tokyo

Acquisitions Ediwr: Jay Campbell Senior Product DevelDpment Ediwr: Amy Millholen DevelDpment Ediwr: Heidi Grauel Ediwrilll Coordinator: John Larkin Marketing Mannger: Shauna Kelley Production Project Mannger: linda Van Pelt Design Coordiruztor: Joan Wendt Manufacturing Coordinawr: Margie Orzech Prepress Vendor: S4Carlisle Publishing Services

Fourth Edition Copyright o 2018 Wolters Kluwer Copyright o 2016, 2012, 2008 Wolters Kluwer Health/Uppincott Williams & Wilkins. All rights reserved. This book is protected by copyright. No part of this book may be reproduced or transmitted in any form or by any means, including as photocopies or scanned-in or other electronic copies, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their official duties as U.S. government employees are not covered by the above-mentioned copyright. Th request permission, please contact Wolters Kluwer at Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103, via email at [email protected], or via our website at lww.com {products and services).

9 8 7 6 5 4 3 2 1 Printed in China

Library of Congress cataloging-in-Publication Data Names: Stephenson, Susan Raatz, editor. I Dmitrieva, Julia, editor. Title: Diagnostic medical sonography. Obstetrics and gynecology 1 [edited by] Susan Raatz Stephenson, Julia Dmitrieva. Other titles: Obstetrics and gynecology Description: Fourth edition. I Philadelphia: Wolters Kluwer Health, [2018] I Includes bibliographical references. Identifiers: LCCN 2017023365 1 ISBN 9781496385512 Subjects: I MESH: Genital Diseases, Female-diagnostic imaging I Ultrasonography I Fetal Diseases-diagnostic imaging I Pregnancy Complications-diagnostic imaging I illtrasonography, Prenatal Classification: LCC RC78.7.U4I NLM WP 141 I DDC 616.07 /543-dc23 LC record available at https:/ jlccn.loc.gov/2017023365

This work is provided ·as is,· and the publisher disclaims any and all warranties, express or implied, including any warranties as to accuracy, comprehensiveness, or currency of the content of this work. This work is no substitute for individual patient assessment based upon healthcare professionals' examination of each patient and consideration of, among other things, age, weight, gender, current or prior medical conditions, medication history, laboratory data and other factors unique to the patient. The publisher does not provide medical advice or guidance and this work is merely a reference tool. Healthcare professionals, and not the publisher, are solely responsible for the use of this work including all medical judgments and for any resulting diagnosis and treatments. Given continuous, rapid advances in medical science and health information, independent professional verification of medical diagnoses, indications, appropriate pharmaceutical selections and dosages, and treatment options should be made and healthcare professionals should consult a variety of sources. When prescribing medication, healthcare professionals are advised to consult the product information sheet (the manufacturer's package insert) accompanying each drug to verify, among other things, conditions of use, warnings and side effects and identify any changes in dosage schedule or contraindications, particularly if the medication to be administered is new, infrequently used or has a narrow therapeutic range. Th the maximum extent permitted under applicable law, no responsibility is assumed by the publisher for any injury and/or damage to persons or property, as a matter of products liability, negligence law or otherwise, or from any reference to or use by any person of this work. LWW.com

DEDICATION In 1985 at the University of Oklalwma Health Sciences Center. I started my ultrasound journey thinldng that the profession was simply a stepping stone. If the profession h.at1 remained WIChanged and WIChallenging this may have been the case. Instead, sonographers htwe had to learn and evolve to keep up with the technology changes. It has been a privilege to learn from and befriend many sonographers who have been of llital support when life, either professiona.Uy or personally, throws you c:uroes. I am forever grateful to all those that keep me humble. SUSAN R. STEPHENSON

7b Mom and Michael without whose understanding and support it would have been impossible. JULIA DMITRIEVA

-A final note from Rasheed Ogun.laru: It's essential to keep moving, learning and evolving for as long as you're here and this world

keeps spinning.

ACKNOWLEDGMENTS

W

orking through the editing process of the third edition was a learning process in the publishing world. Thinking, incorrectly, that the fourth edition would be easier was the first misconception to fall. Once again, I learned from the authors and my coeditor Julia Dmitrieva. Invaluable support was given by fellow editors Diane M. Kawamura and Tonya Nolan (abdomen) and Anne Marie Kapinski (vascular) in creating the newest trilogy of Diogrwstic Medical Sonography.

vi

Many thanks to the production team at lippincott Williams & Wilkins who helped edit, product, promote, and deliver this textbook. We especially thank in the development of this edition Heidi Grauel for her patience, guidance, and editing skills. To colleagues, students, friends, and family, who give unlimited encouragement, enthusiasm, inspiration, plus a sympathetic ear, I am grateful.

Susan R. Stephenson, MS, MAEd, RDMS, RVI', CUP

PREFACE

T

he restructured fourth edition of Diagnostic Medical Sonography: Obstetrics and GynecolDgy follows input from instructors who use the textbook. Separation of chapters in the Obstetrics section to follow fetal systems offers continuity by presenting embryonic development and normal and abnormal anatomy divided by system. This edition continues to give information recognizing the diverse backgrounds and experiences of readers. This textbook continues to be useful as an introduction to the profession or as a continuing reference. The content lays the foundation for a better understanding of anatomy, physiology, pathophysiology, and complementary imaging for the sonographer practitioner, sonographer, sonologist. or student when caring for the patient. The textbook has two major sections, with the first being gynecology and the second obstetrics. The first chapters in each section, "Principles of Scanning Technique in Gynecologic lfltrasound" and "Principles of Scanning Technique in Obstetric lfltrasound," have information on patient care and the process of beginning the gynecologic or obstetric exam. The first chapter describes picture archiving and communication systems (PACSs) and interconnected computer systems within a clinic or hospital that have revolutionized our profession and daily workflows. Both introductory chapters offer methods to care for the patient while performing the ultrasound exam.

Throughout the chapters, we have tried to incorporate instrumentation and complementary imaging modalities when appropriate. This allows for integration of sonographic physics as well as other imaging modality findings that sonographers often encounter. We made every attempt to produce an up-to-date and factual textbook, at the same time presenting the material in an interesting and enjoyable format to capture the reader's attention. To do this, we provided detailed descriptions of anatomy, physiology, pathology, and the normal and abnormal sonographic representation of these anatomic and pathologic entities. illustrations, summary tables, and images include valuable case study information. Our goal is to present as complete a text as possible, recognizing that current journal readings must supplement the content. With every technologic advance made in equipment, the sonographer's imagination must stretch to use new applications. With the comprehensive foundation available in this text, the sonographer can meet that challenge. Susan R. Stephenson, MS. MAEcL ROMS, RVT, CliP Julia Dmitrieva. DBA, ROMS (OB)(AB) (BR). RDCS,RVf

vii

CONTRIBUTORS Karen Ambrowitz, RDCS

Arri Hall-Terracciano

Technical Director Pediatric Echocardiography Laboratory UCLA Mattel Children's Hospital Los Angeles, California

Dixie Regional Medical Center St. George, Utah

Lisa Allen, BS, RDMS, RDCS, RVT, FAIUM

Ultrasound Coordinator The Regional Perinatal Center State University of New York Upstate Medical University Syracuse, New York Liana Amarillas, BS, RDMS (ABD)(OB), RVT, RDCS

Diagnostic Medical Sonographer Divisions of Ultrasound and Prenatal Diagnosis University of Colorado Hospital Aurora, Colorado Amanda Auckland, RDMS, RDCS, RVT

Sonographer Department of Ultrasound University of Colorado Hospital Aurora, Colorado Sue Benzonelli-Blanchard, BS, RDMS, RDCS

Ultrasound Consultant Issaquah, WA Danielle M. Bolger, RT, RDMS, RVT, RDC

Department of Ultrasound University of Colorado Hospital Aurora, Colorado Molina Dayal, MD, MPH, FACOG

Medical Director Sher Institute of Reproductive Medicine St. Louis, Missouri Greggory DeVore, MD

Division of Maternal-Fetal Medicine Department of Obstetrics and Gynecology David Geffen School of Medicine at UCLA Los Angeles, California Fetal Diagnostic Centers Pasadena, Tarzana, and Lancaster, California

Faith Hutson, BAS, RT, RDMS

OMS Clinical Coordinator Diagnostic Medial Sonography Dona Ana Community College Las Cruces, New Mexico Catheeja Ismail, RDMS, EdD

Staff Sonographer Assistant Professor of Radiology, The George Washington Uni ,ersity Hospital Washington, District of ('.; lum6ia Sanja Ku

Clinical and Depar Pa 1 L

1cs & Gynecology al Education ol of Medicine

Bridgette Lunsford, MAEd, RDMS, RVT

Clinical Applications Specialist GE Healthcare - Ultrasound Arlington, Virginia Darla Mathew, BAS, RT, RDMS

OMS Program Director Diagnostic Medical Sonography Dona Ana Community College Las Cruces, New Mexico Amber Matuzalttl BEST. Pl\TIENTV 31Yoars F

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I

PRINCIPLES OF SCANNING TECHNIQUE IN GYNECOLOGIC ULTRASOUND

Soft 11uua

II

Force applied

Adenomyosis

Uterus Fibroid Hard

B

A

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FIGURE I~ Schematic diagram of use of real-1ime sonoelastDgraphy. k Transducer pressure applied 1D the uterus causes deformation of tissue. Deformation caused by compression depends on 1issue stiffness, with mone deformation in soft tissue than in harder tissue. B: Cha~ in deformcdion is color-coded and is 5Uperimposed on the torTeSponding B-mode image. We mos11y used the "ascending colors' color map on 1he ultrasound macnine: darlc purple or blue indi credentialing bodies, that is, the Na1ional Commission for Certifying Agencies (NCCA), http://wwiN.ncxa.org/ncca/ncca.htm; or the International Organization for Stlndardization (ISO), http://wwiN.iso.orgt'lso/en.IISOOnline .frontpage. C. Uphold professional standards by adhering to defined technical protocols and diagnostic criteria established by peer review D. Acknowledge personal and legal limit>, practi~ wiltlin the defined scope of practice, and assume responsibility for his or her actions E. Maintlin continued competence through lifelong leaming, which includes continuing education, acquisition of specialty specific credentials, and F. G. H. I.

recredentialing Perform medically indiated ultrasound studies, ordered by a licensed physician or a designated health care provider Protect patients and/or study subjects by adhering to oversight and approval of investigational procedures, including documented informed consent Refrain from the use of any substlnces that may alter judgment or skill and thereby compromise pa:tient care Be accounlable and participate in regular assessment and review of equipment, procedures, protocols, and results. Facility accreditation acwmplishes this goal.

Principle Ill: To pr~ profeuionol integrity and ~>Ublic tn.lst., the diagnostic medicGI sonogropher shall:

A B. C. D. E. F. G. H. I.

J.

Be truthful and promote appropriate communications with patients and colleagues Respect the rights of patients, colleagues, and yourself Avoid conflicts of interest and si1lJations that exploit others or misrepresent information Accurately represent his or her experience, education, and O'edentialing Promote equitable access to care Collaborate with professional colleagues to create an environment that promotes communication and respect Communicate and collaborate with others to promote ethical practice Engage in ethical billing practices Engage only in legal arrangements in the medical industry Report deviations from the Code of Ethic; to institutional leadership for internal sanctions, local intervention, and/or criminal prosecution. The Code of Ethic; can serve as a valuable tool to develop local polides and procedures.

The Society of Diagnostic Medical Sonographers. Code ofPr~ CondLICt (or Diagnostic Medicd Sonotfaphers. Dallas: SDMS; 2006.

I PRINCIPLES OF SCANNING TECHNIQUE IN GYNECOLOGIC ULTRASOUND

PROFESSIONAL RESPONSIBILITIES OF THE SONOGRAPHER In March 2002, the Bureau of Labor Stati.stics26 classified sonography as a unique professional classification and it became listed in the Occupational Outlook Handbook.z7 1t is essential that sonographers be familiar with the Sonographer's Code of Professional Conducf8 (Table 1-4), Code of Ethics,19 The Scope of Practice7; that they abide by the Patients' Bill of Rights; and that they practice infection control techniques to protect their patients and themselves. Individuals choosing diagnostic ultrasound as a profession should take certifying examinations. Passing a credenti.aling examination attests that the sonographer has a practicing level of knowledge in the specialties in which he or she is registered. There are currently several testing bodies in the United States, such as the American Registry of Radiologic Technologists (ARRT); however, the gold standard is still the test given by the American Registry of Diagnostic Medical Sonographers (ARDMS). The ARRT test contains general topics, whereas the ARDMS specifies specialty areas such as obstetrics/gynecology. When deciding which test to take, be sure of acceptance by your facilities' accrediting body. Based on the National Competency Profile for Sonography, the Canadian exam contains a core competency section with a Generalist Sonographer designation. This examination tests on multiple topics to include obstetrics, gynecology, abdomen, and vascular topics. There are also dedicated tests for the cardiac and vascular specialties. If you wish to scan in a specific country, make sure to check credenti.aling requirements because they vary. Th maintain registry status, the sonographer must complete continuing medical education (CME) credits depending on the credential held and credentialing body. In a field as

SUMMARY

• The sonographic examination begins with entry of patient data into the EMR, RIS, and, if available, the MWL on the equipment. • The performing sonographer introduces himself or herself, confirms patient identity through multiple methods {name, date of birth, exam, armband), and takes a history. • Each imaging laboratory must develop an imaging protocol to ensure completeness of the exam and consistency between examinations. • A transabdoiillnal examination of the female reproductive organs begins with an adequately full bladder. • 'Ihmsducer selection depends on the transducer footprint, body habitus, examination, and stage of pregnancy. • Endovaginal examinations require covering of the transducer. • Professionalism is partially determined through obtaining certification and maintaining registries through CME completion. CRITICAL THINKING QUESTIONS 1. You have been asked to be part of a hiring committee

for the sonography department. After reviewing the

13

dynamic as diagnostic ultrasound, keeping informed of innovations is imperative. Without CME maintenance, none of the testing bodies list the registrant on the web page directory search as an active member. Many credentialing bodies require recertification at regular intervals. In the United Sates, the AlUM accredits practices that image obstetric, gynecologic, abdominal, and breast ultrasound areas. 23 Another governing body, the ACR, also accredits imaging laboratories. The AlUM requires the ARDMS registry in the accrediting specialty areas; however, they do accept the ARRT Breast certification.24 The ACR accepts either the ARD.MS or the ARRT credential.25 Each requires the proper education and credenti.aling of sonographers in the practice. Add to this the increasing requirements by third-party payers, such as Medicare- that will only reimburse for examinations performed in accredited labs with certified sonographers-and it becomes clear that anyone perfonning the sonographic examination has to have credentialing. The sonographer should become a member of a professional society in his or her area of practice, in this case, General and Women's Health Imaging. Examples of societies include the SDMS, the AlUM, or even the International Society of mtrasound in Obstetrics and Gynecology (ISUOG). Membership in a society brillgs with it the benefits of being part of a professional organization whose mission is to keep its members informed and competent. Among the resources the societies include are educational guidelines, profiles of sonographer characteristics (including salary levels), peer-reviewed journals (The Journal of Diagnostic Medical Sorwgmphy, Journal of

Ultmsowul Medicine, Ultrasowul in Obstetrics and Gynecology), and annual national and regional scientific meetings. It also keeps its membership informed of legislation and current societal trends that can affect the practice of ultrasound at the local, national, and international level.

applicants' application material. you want to verify CME, ARDMS, and ASRT registry status. What resources would you use to perform this task? 2. As a newly appointed CMB coordinator in a hospital located in the United States. it is your responsibility to find and provide educational opportunities for your feDow sonographers. What Ie80urce8 would you use to set up your own program? How would you locate bldependent study ac:dvfties at Utde or no cort? 3. An obstetridan's offke would like to become ~ted to ensure quaUty sonographic examinations. Thia office images from the first trimester to term, performing early pregnancy screening for aneuploidy. What is the flm step in becoming accredited within the United States? MEDIA MENU

Student Resources available on • Audio glossary • Interactive question bank • Videos • Internet resources

Point' include:

14

PART ONE GYNECOLOGIC SONOGRAPHY

REFERENCES 1. American Institute of Ultrasound in Medicine. Official Statement As Low As Reasonably Achievable (ALARA) Principle. Laurel, MD: AlUM; 2014. 2. Shortliff EH, Cimino JJ. Biomerlical. Infomwtics: Computer Applications in Health Care and Biomedicine. 4th ed. New York: Springer; 2014. 3. Hacker NF, Moore JG. Essentials of Obstetrics and Gynecowgy. Philadelphia: WB Saunders; 1986. 4. Hansman M, Hackeloer BJ, Staudach A. Ultrasound Diagnosis in Obstetrics and Gynecowgy. Berlin: Springer-Verlag; 1985. 5. American Institute of Ultrasound in Medicine. Guidelines for Per· formance of the Antepartum Obstetri.cal Ultrasound Examination. Laurel: AlUM; 2007. 6. American Institute of Ultrasound in Medicine. Guidelines for Performance of the Ultrasound Examination of the Female Pelvis. Laurel: AlUM; 2009 . 7. Society of Diagnostic Medical Sonographers. The Scope of Practi.ce for the DiagnDstic Medical Sonographer. Dallas: SDMS; 2009. 8. American Institute of Ultrasound in Medicine. Bioeffects committee reviews RADrUS study. AlUM Report. 1994;10:2-4. 9. Kremkau F. Diagnostic lRtrnsound: Principles and Instruments. 9th ed. Philadelphia: Saunders Elsevier; 2011. 10. Hedrick WR. Thchrwlogy for DiagnDstic Sonography. St. Louis: Elsevier Mosby; 2013. 11. Society of Diagnostic Medical Sonographers. Sonography Examination Guidelines. 2nd ed. Plano: SDMS; 2006. 12. American Institute of Ultrasound in Medicine. Guidelines for cleaning and preparing endocavitary ultrasound trnnsdu.cers between patients. AlUM Official statement. Laurel: AlUM; 2014. 13. Stoelinga B, Hehenkamp W, Brolmann H, et al. Real-time elastography for assessment of uterine disorders. Ultrasound Obstet Gynecol. 2014:43:218-226. 14. Furukawa S, Soeda S, Watanabe T, et al. The measurement of stiffness of uterine smooth muscle tumor by elastography. SprtngerPlus. 2014;3:294. 15. Bakay 0, Golovko T. Use of elastography for cervical cancer diagnostics. F.xp Oncol. 2015;37(2):139-145. 16. Elsayes KM, Pandya A, Platt JF, et al. Thchnique and diagnostic utility of saline Infusion sonohysterography. Int J Gyno.ecol Obstet. 2009;105(1):5-9.

17. Chan CC, Ng EH, lang OS, et al. Comparison of thre.e-dlmensional hysterosalpingo-contrast-sonography and diagnostic laparoscopy with chromopertubation in the assessment of tubal patency for the investigation of subfertility. Acta Obstet Gynecol Scand. 2005;84(9):909-913. 18. De FeliceC, Porfiri LM, Savelli S, et al. Infertility in women combined sonohysterography and hysterosalpingography in the evaluation of the uterine cavity. Ultraschall Med. 2009;30(1) :52-57. Erratum in: lRtraschaU Med. 2009;30(2) :195. 19. Andrist L, Katz v, Elijah R, et al. Developing a plan for routine 3-dimensional surface rendering in obstetrics. J Diagn Med Sonogr. 2001;17:16-21. 20. Ballard·Taraschi K, Roberts D, ThompsonS. Utilizing 3D ultrasound to visualize trisomy 18 abnormalities in the first trimester. J Diagn Med Sonogr. 2003;19:110-113. 21. Fauchon DE, Benzie R.J, Wye DA, et al. What information on fetal anatomy can be provided by a single first-trimester transabdominal three-dimensional sweep? Ultrasound Obstet Gynecol. 2008;31(3):266-274. 22. Hata T, Dai SY, Inubashiri E, et al. Real-time three-dimensional color Doppler fetal echocardiographic features of congenital heart disease. J Obstet Gyno.ecol Res. 2008;34(4, pt 2):670-673. 23. American Institute of Ultrasound in Medicine. Standards and Guidelines for the Accreditation of UltrasolUld Practices. Laurel: AlUM; 2005. 24. American Institute of Ultrasound in Medicine. Ultrasound Practice Aa:red.it:ation: The Measure of Excellence. Laurel: AlUM; 2009. 25. American College of Radiology. Ultrasound Accreditation Program Requirements. Reston: ACR; 2009. 26. Society of Diagnostic Medical Sonography. Press release http:/I www.sdms.org/news/release03182002.asp. Accessed August 2017. 27. Occupational Outlook Handbook, 2008-2009 Edition. http://www .bls.gov/oco/ocos273.htm. Accessed August 2017. . 28. Society of Diagnostic Medical Sonographers. Code of Professwnal Conduct for Diagnostic Medical Sonographers. Plano: SDMS; 2006. 29. Society of Diagnostic Medical Sonographers. Code of Ethics for the Profession of Diagnostic Medical Sonography. Plano: SDMS; 2006.

.

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•

Embryonic Development of the Female Genital System SUSAN R. STEPHENSON

OBJECTIVES

KEY TERMS

■ Order the appearance of embryonic structures

embryogenesis

■ Describe the first-trimester Carnegie staging

urogenital

■ Relate embryonic structures to the resultant adult organs

primordial germ cells

■ List the development stages of the female reproductive system

mesonephros

■

pronephros

Explain the interconnect1v1ty of the urinary and reproductive systems

inducer germ cells

GLOSSARY ~ ------- ·---------- ------------------------ -------~- -------- --------~~-------------- --- ·-------

Allantois Sac-like vascular structure that lies below the ch

·

-- . -- --- . -- -the

mesonephric ducts paramesonephric ducts

hindgut

mullerian ducts

Atretic Blockage or absence of a structure

external genitalia

Broad ligament Fold of peritoneum that connects the uterus t G the pelvis

wolffian ducts

Embryogenesis Formation of an embryo Cloaca Cavity that is part of the development of the l:l igest\,e and reproductive organs Diploid Normal number of paired chromos0 mes Gonadal ridges Structure that appears at appKQ~tely 5 weeks gestation and becomes either ovaries or testes

I

•

• 'V""'

Hydrometrocolpos Accumulation of secreteEJ ~uid resulting in distention of the uterus and vagina because of obstruction Hydronephrosis Urine collection in the kidneys because of distal obstruction Hydroureter Large, sometimes t0 rtuous , ureter because of distal blockage Mesonephric ducts Connection between the mesonephros and the cloaca Mesonephros Second stage of kidney development (aka wolffian body) Mesovarium Section of the uterine broad ligament that covers the ovary Mullerian ducts (paramesonephric ducts) Paired ducts that become the oviducts, uterus, cervix, and upper vagina

Oocytes Female germ cells Oogonia Immature oocytes Paramesonephric ducts see mullerian ducts Primordial germ cells Precursor of germ cells, become oocytes or spermatozoa in the adult

Pronephros Primary or first kidney, which develops in the embryo Wolffian ducts see Mesonephros Urogenital Pertaining to the urinary and genital system

IS

I

16

PART ONE GYNECOLOGIC SONOGRAPHY

U

nderstanding female reproductive anatomy begins with a thorough knowledge of the pelvis structure embryogenesis. Imaging of the uterus and ovaries becomes complicated in the presence of developmental anomalies because of changes in the normal sonographic anatomy. Understanding the developmental relationship between the urinary and reproductive systems requires knowledge of normal and abnormal development of both organ systems. Commonly, anomalies in either systems result in coexisting malformations in the other. The urogenital system easily images in utero and throughout a woman's life. This allows for diagnosis of morphologic anomalies in all stages of life from fetal, neonatal, pediatric, reproductive, and postmenopausal. carnegie stagi7t8, a method used to classify the embryo, places the embryo into categories depending on age, size, and morphologic characteristics. The embryo develops structures in a specific order that remains constant. Because, as with any organism, each develops at a different rate, the segmentation of development allows for consideration of morphologic development, regardless of dates. 1 Carnegie staging applies to the first 8 weeks of the gestation and pertains to the organogenesis of the embryo. The resulting 23 stages end after the eighth week when the fetal period begins. Carnegie stages will be included with each organ development chapter. This chapter covers the normal development of the female urogenital structures, including the correlating Carnegie stages. Abnormalities of development are further discussed in the next chapter.

FETAL PERIOD The genitourinary system encompasses two systems: reproductive (genito-) and urinary. These systems develop in tandem in the embryo and retain the close association in the adult. Most congenital anomalies discovered in fetuses in utero occur in the genitourinary system, with urinary tract abnormalities accounting for about 50% of the total.2 These anomalies represent a wide range, from complete agenesis of the kidney and ureters to partial malformations, duplications, and obstructions with concomitant cyst formation. Prenatal ultrasound may also detect congenital anomalies in the ovaries, uterus, and vagina, especially when they enlarge and produce a pelvic mass. Cloacal anomalies, which can result in hydrometrocolpos, are the result of obstruction of vaginal outflow in the female fetus. 3 This hypoechoic mass posterior to the bladder compresses the urinary tract, causing obstructive uropathy demonstrated by hydronephrosis or hydroureter. 3

NEONATAL PERIOD As in the fetal period, the most common mass lesions in neonates are of renal origin4 ; however, ovarian cysts are known to be the most common intra-abdominal lesion in the neonate. 5 Identify the normal urinary bladder, uterus, vagina, and (whenever possible) ovaries when imaging the pelvis in a newborn girl to rule out masses and obstructions.

PREMENARCHETHROUGH ADULTHOOD The onset of puberty results in menstrual irregularities and, thus, a visit to the sonography lab. This often is the first time any developmental abnormalities become apparent. For example, in the patient with a duplicated uterus with one septate vagina, obstruction to menstrual flow from one side can present as unilateral hematocolpos. 6 In these patients, imaging of the kidneys becomes important because there are often associated anomalies. 6 Asymptomatic patients may not be aware of the congenital anomalies unless other conditions require sonographic imaging. These anomalies occur early in embryonic life. The following sections review the development of the female internal and external genitalia.

EXPRESSION OF GENDER IN AN EMBRYO The Primordial Germ Cells The chromosomal gender or sex is determined in the first Carnegie stage at fertilization with the fusion of the sperm and egg. 1 This stage is also called the pre-embryonic phnse, which lasts into the third week. 1 The female gamete (the ovum) always contains the X sex chromosome. The male gamete (the spermatozoon) contributes either an X (female) or Y (male). If the sperm contributes an X to the ovum's X, the result is a female zygote (XX). If the male contributes a Y chromosome, the result is a male zygote (XY) .6 Fertilization results in a diploid chromosome count of 46 with two sex chromosomes (XX or XY). The primordial germ cells that express or produce femaleness or maleness are first discernible in the embryo late in the third week to early in the fourth week (approximately the 17th day1 after conception. This stage, the embryonic phase, begins in the fourth week and extends into the eighth. 1 The appearance of the primordial germ cells along with the primitive groove, streak, and node indicate Carnegie stage 6. 1 These germ cells differentiate from cells in the caudal part of the yolk sac, close to the allantois (a small diverticulum of the yolk sac that extends into the connecting stalk) (Fig. 2-lA). In the sixth week during Carnegie stage 17/ the primordial germ cells migrate from the yolk sac along the allantois and into the gonadal cords.6•7 The genital or gonadal ridges form simultaneously and are the precursors to the female ovaries and to the male testes. These ridges are located on the anteromedial sides of the mesonephros, the embryonic regions where the kidneys develop (Fig. 2-1B). 7 The urinary system and the reproductive system are intimately associated in origin, development, and certain final relations. Both arise from mesoderm that initially takes the form of a common ridge (mesonephros) located on both sides of the median plane. This tissue appears during the sixth Carnegie stage at about 13 days postovulation.2 Both systems continue to develop in close proximity; they drain into a common cloaca and slightly later into a urogenital sinus, which is a subdivision of the cloaca. Some parts of the urogenital system disappear after a transitory existence.8 For example, by the fifth developmental week, the first-stage

2 EMBRYONIC DMLOPMENT OF THE FEMALE GENITAL SYSTEM Hindgut

Foregut

17

Allantois

Genhal ddge

A

Mesonephric

Aorta

Primordial~. • genm cells

' . \ urtesy of GE Healthcare, Wai.matasa, \NI.)

A

Cervical incompetence has been reported in about 36% of bicornuate uterus anomalies, and the placement of a cervical cerclage has been reported to increase fetal survival rates.4 Pregnancy Outcomes Women with bicornuate uterus but no other extrauterine infertility issues usually have no difficulty conceiving; however,

B

FIGURE 3-10 Gravid bicornuate uterus. Coronal Half-Fourier Acquiree Single-shot Turbo spin Ecno (HASTE) image demonstral:ei second uterine hom (om:w) in pregnant patient with bicornuate uterus.

FIGURE l-11 A:. Hysterosalpi~ demonstrating a larie uterine septum. This cannot be disti'll'Jished from a bicomuate uterus in the absence of careful evAIUa-,-;.;--+-

52

~~~---'r- 53

54

Medial umbilical ligament (obiHerated umbilical anery)

'-lnk>fl•vgluteel artery

lntemal pudendal artery

Inferior vesical branch of vaginal Uterine artery

A

"'Vaginal anery arises frcm uterine artery in 11% of cases

FIGURE 5·56 A: Arterial supply to the uterus. The broad ligament has been removed to expose the uterine artery as it cour1;es upward from the level of the cervix to the cornu of the uterus, where it makes a sharp tum to run along the underside of the fallopian tube. The uterine artery forms an anastomosis witn the avarian artery beneath the fallopian tube. Thus, ahhou:gh the uterine artery is the principal supplief' of blood to the uterus. it is not the sole supplier. Anastomotic connedions are not limited to the uterine~rian arteries. They are found throughout the peMs, providing an elaborate fail-safe networlc. of altemate d1annels to each of the O'iliii'IS. B: This transvene endCMljljnal image ofthe region of the uterine isthmus (Ut) uses color Doppler to demon~ the abundant vessels 1ha11ie along the lateral uterine margins. Blood flow is indicated by the presence dcolor.

gonadal arteries, originate as lateral branches of the aorta at about the level of the lower margin of the renal pelvis (Fig. 5·57). These arteries course downward over the psoas muscles and along the same path followed by the ureters, crossing over the common iliac artery just superior to its bifurcation into the external and internal iliac arteries. The ovarian artery then bridges across from the upper margin of the pelvis to the ovary through the infundibulopelvic ligament. From the infundibulopelvic ligament it passes through the mesovarium to reach the ovarian hilum, where it supplies the ovarian parenchyma. In addition, the ovarian artery forms anastomoses with the ovarian branches of the uterine artery, thus providing a closed-loop or fail-safe

blood supply originating from two widely divet:gent points in the arterial system.

Venous System of the Pelvis The venous system of the pelvis follows a pattern virtu· ally identical to that of the arterial system. The inferior vena cava bifurcates slightly below the level of the aortic bifurcation, giving rise to the common iliac veins, which run beneath the common iliac arteries. These short ves· sels in turn give rise to the large external iliac veins, which drain the legs, and the internal iliac veins, which drain the pelvic organs and muscles. The ovarian veins

112

PART ONE GYNECOLOGIC SONOGRAPHY

Aorta Internal lilac artety (aka hypogas1rlc artery)

All Yia branches All via branches

External and internal iliac Uterine, ovarian, bladder, rectum, umbilical artery In the fetus

Uterine artery Ovarian (aka gonadal) artery

Uterus, &llopian tube. ovary, vagina Ovary, ureters, fallopian tube

Arcuate, vacinaJ

follow the same course as the ovarian arteries until they reach the mid-abdomen, where the right ovarian vein drains directly into the vena cava and the left ovarian vein drains into the left renal vein. Because the veins are thin walled, they are highly distensible and vary in size with certain conditions, most notably pregnancy. After parturition, the venous channels usually shrink,. but they may remain prominent and easily visible. If venous congestion occurs, the veins may form pelvic varices, which are readily identifiable in the ultrasound image. In some women, particularly after parturition, the venous channels in the outer regions of the myometrium are clearly visible.

The Ureter

The ureters course along the lateral pelvic wall posterior to the ovary. These musculomembranous tubes move urine by peristalsis and enter the pelvis at a point just caudad to the bifurcation of the common iliac vessels. The ureter is posterior and lateral to the ovary, with the most common position lateral to the uterus (Fig. 5-58). As the ureter descends into the pelvic space, it moves medially to reach the trigone of the urinary bladder, and therefore oblique scan planes are usually required to demonstrate long segments of the ureter in the pelvis. Real-time sonography images ureteral contractions, with endovaginal images identifying the ureter easier than transabdominal imaging.

Abdominal part of esophagus {cut)

Diaphragm

Left suprarenal gland Left kidney

Celiac trunk Superior mesenteric artery (cut) Left renal artery and vein

Transversus A Orientation

abdominis musde Quadratus lumborum muacle

Abdominal aorta Inferior meeentertc artery ~ Iliac crest

Ovarian artery and vein

Right ureter

Psoasma;or musde

Left ureter

Iliac arteries: Common Internal External

Uterus

Urinary bladder

Rectum

B Anterior view FIGURE 5-57 The blood supply d the ovaries. The uterine artery and the ovarian artery fonn anastomoses in the ~on d 1he ovarian hilum. Note 1he difference in the pattem d 01/arian artery ori.fDn venus OYarian vein tennination. Beause lymphatic:s follow 1he gonadal (01/arian) vessels, tumor spread fi'om the peMs to 1he para-aortic nodes at the level of1he n:nal peNis is common.

5

A

NORMAL ANATOMY OF THE FEMALE PELVIS

113

B

FIGURE 5·58 .Sagittal scans o! th~ avary and surround in~ vessels. A: M endovagjnal image demonstratir'4!the imemal iliac: artery (lA), imemal iliac: vein (1"1), and a normal~ B. A transabdom1nal1mage on a more med~al scan plane demonstrates mostly ovarian tissue, with the ureter (arrows) running postetiortt>the cmry. UBL. unnary bladder.

ENDOVAGINAL TECHNIQUE. TRANSDUCER PREPARATION, ORIENTATION. AND MANIPULATION A female chaperone should be present when a male sonog· rapher or physician performs an endovaginal examination. Explain the examination to the patient before a procedure to help alleviate anxiety. Place the patient in the lithotomy position, ideally on a gynecologic examination table. If such a table is not available, the patient's hips can be elevated with a foam pad or pillow. Ensure complete coverage of the pelvis and legs. 1b prepare the transducer, apply scanning gel directly on the transducer footprint prior to placing a protective sheath over the transducer. Eliminate any air bubbles between the transducer and sheath with a gloved hand. Place a generous amount of sterile gel on the outside of the sheath before gently inserting the transducer into the vaginal canal. If the

FIGURE 5·59 A TAS in sagitlal view demonsb'al:es the anterior aspect (patient's abdomen) at the top ofthe screen, the posterior aspect (patient's back} at the bottom, superior (toward patient's head) is to 1he left d the image and inferior (toward patient's feet) is at the right d the image.

study is part of an infertility workup or follicular monitoring, use saline or water to lubricate the sheath, because gel may inhibit sperm motility. If using commercial condoms, ensure they are free of spermicide. The sonographer, the physician, or the patient herself can then insen the transducer. Avoid ememe angling of the transducer because this may be uncomfortable. Nongravid and pregnant patients easily tolerate a well-performed endovaginal examination. EVS im· ages have a different orientation compared to conventional transabdominal images because of the transducer location. The typical orientation for a pelvic transabdominal image demonstrates that the structures closest to the footprint of the transducer are at the top of the image screen. Figure 5·59 illustrates a typical TAS sagittal view demonstrating the anterior aspect {patient's belly) at the top of the screen, the posterior aspect (patient's back) at the bottom, superior (toward patient's head} to the left of the image and inferior (toward patient's feet) at the right side of the image. As a result, when in the longitudinal plane performing a EVS examination, the bottom of the screen is oriented toward the patient's head (superior); the top of the screen is toward the patient's feet (inferior}; the left side is the patient's belly (anterior) and the right is the patient's back (poste· rior), as demonstrated in Figure 5·60. The organ-to-image orientation depends on the position of the uterus within the pelvis. Obtain coronal and oblique coronal images, which are equivalent of transverse images produced by TAS. The antevened uterine position occurs with an empty bladder, allowing for acquisition of images on this plane. !n transverse (coronal/oblique coronal) EVS imaging, as m the conventional transabdominal orientation, the right side of the patient corresponds to the left of the screen and the left side of the patient corresponds to the right of the screen (Fig. 5·61). Orientation of the image often begins with how the so· nographer holds the transducer. The EV transducer, like any other transducer, has a notch or raised portion to indicate the orientation. Most transducers orient this marker with the manufacturer logo next to the top of the image. For sagittal images, the marker is up toward the front of the patient.

114

PART ONE GYNECOLOGIC SONOGRAPHY

4. Rotation 5. Bimanual maneuvers

ANTEROPOSTERIOR ANGULATION In the longitudinal plane, AP angulation allows the operator to optimize imaging of the uterus (Fig. 5-62}. A slight and

gradual downward movement of the transducer's handle angles the transducer upward, allowing better visualization of an anteverted uterus. Conversely, an upward motion of the handle angles the transducer toward the patient's back, allowing better visualization of a retroverted uterus.

Lateral Angulation FIGURE 5-40 h1 EVS examination. The bottom of the screen is oriented toward the patient's head (superior); the top of the screen is toward the patient's feet (Inferior); the left side is the patient's belly (anterior) and the right is the patient's back (posterior).

Side-to-side manipulation of the transducer improves visualization of a uterus deviated to the right or left of midline, the cornua of the uterus, and the ipsilateral ovary, fallopian tube, pelvic vasculature, ligaments, bowel, and other organs or structures (Fig. 5·63). Many pieces of equipment allow for steering of the beam without the need for transducer manipulation. Upon decreasing the sector width, quite often the sonographer is able to steer the beam to the right or left of the central beam. This becomes helpful in the patient with ovaries located extremely lateral in the pelvis. This steering technique is also helpful in imaging the anteverted or retroverted uterus.

Depth of Penetration versus Resolution Changes in depth of penetration created by a gradual advancement or withdrawal of the vaginal transducer allow the sonographer to image an organ or structure by placing it within the central portion of the transducer's field of view (Fig. 5-64). Changing the frequency also allows the sonographer to vary the depth of penetration. A lower frequency increases the depth of penetration to include FIGURE 5-61 EVS image in oblique transverse view.

For coronal images, rotate the notch counterclockwise (toward the patient's right). Some endovaginal. transducers have a slanted face, requiring a little different technique for the coronal views. Rotation of the transducer in the above method works well for the right ovary; however, to image the left ovary, the marker must be rotated clockwise. This results in reversal of the image. 1b remedy this, locate the invert function to flip the image. Obtain the left ovary images and do not forget to orient the image to the original plane. Many authors found it easier to use "organ-oriented"' scanning rather than trying to locate traditional anatomic planes. This approach entails scanning the target organ from axial, longitudinal, as well as other planes.21-23 The technique of EVS examination and image interpretation becomes easier to discuss upon understanding the basic concept of image orientation. The most common transducer/ patient manipulations are the following: 1. AP angulation (belly-to-back) 2. Lateral (side-to-side) angulation 3. Depth of penetration (push-pull)

FIGURE 5-Q Sdtemalic diagram demonstrati~ the movement of1he 1ransducef' to produce sagittal views c:i the urerus in the same plane. The transducer handle is moved anterior and posterior to view all the sections of the urerus in the sagittal plane. (From DuBose TJ. FetDI Sonor/ophy. Philadelphia: WB Saundet"S; 1996:61--04; illustration by VICtoria Vescovo Aldennan, MA. ROMS.)

5

NORMAL ANATOMY OF THE FEMALE PELVIS

liS

the highest frequency, shallowest depth, and the smallest sector size.

Rotation A 90-degree counterclockwise rotation of the transducer allows for imaging in the "semicoronal'" or oblique transverse planes (Fig. 5-65). This rotation, coupled with slow maneuvering of the transducer handle up and down (AP angulation), produces a sweep of the pelvic anatomy from the superior to the inferior regions. Lateral angulation provides focus to either the left or right side in the "'semicoronal" transverse plane of the adnexa and its contents.

Bimanual Maneuver

____.. FIGURE 5-63 Schematic diagram demonstming 1he movement of1he transducer to view sagittal images in difl"erent planes. As the transducer is angled from one side to the other, parallel slices of the uterus are imaged. {From DuBose 1). Ferd Sonogr~. Philadelphia: WB Saunders; 1996: 61--64; illustration by VICtoria Vescovo Alderman, MA. RDMS.)

structures higher in the pelvis; however, this comes with lower resolution. A higher frequency limits the depth of the sttuctures in the true pelvis. The higher resolution increases the image resolution. Decreasing the sector size also changes the resolution through changes in line density. The smaller sector size results in more lines within the sector, thus increasing the resolution. 1b obtain the optimal image resolution, use

Another aid in optimizing endovaginal imaging is the bimanual maneuver. The sonographer places his or her free hand on the patient's pelvic area and gently applies pressure over the site of interest. This maneuver displaces bowel and moves organs or structures located higher in the pelvis into the EVS transducer's field of view. The bimanual maneuver can also help the examiner discriminate between a uterine and nonuterine mass. A uterine mass moves with the rest of the uterus. whereas a nonuterine mass slides past the uterine wall. This is also beneficial in ovarian masses. The EVS examination of the female pelvis should begin by imaging the cervix, with the transducer incompletely inserted, increasing the distance between it and the cervix. Image the entire uterus sagitally by angling the transducer from one side to the other Oateral angulation). View the

/

a

FIGURE 5-64 Schematic diagram demonstr.!ling 1he movement the transducer 1o view s1Tuct1J~ at varioos dista~ from the fornix:. Pushing the transducer deeper into the fomix brings more distant structures into the field of view, whereas withdrawing the 1ransducer permits visualization of the cervix. (From DuBose TJ. Ferd ~· Philadelphia: WB Saunders; 1996:61--64; illustration byVictoriaVesc:oi/OAiderman, MA, RDMS.)

FIGURE 5-65 Schematic diagram demonstming the 100\fement of1he tnnsducer to view semirorona)ftrGnsverse irna:ges of the uterus. Beginning in a sagittal plane, the transducer is rotated 90 degrees counterdock.wise to image 1tle uterus in transverse, with 1tle right adnexa appearing on the right side of the screen. (From DuBose 1). FettJ15onoRraPirY. Philadelphia: W8 Saunders; 1996:61-64; illustration by VICtoria Vescovo Alderman. MA. RDMS.)

116

PART ONE GYNECOLOGIC SONOGRAPHY

transverse planes by rotating the transducer 90 degrees counterclockwise and angle it anterior to posterior to visualize all sections of the uterus and the cul-de-sac. Image the ovaries in both planes, using the same landmarks as in TAS. In postmenopausal women, the lack of follicles may make the ovaries more difficult to locate. The American College of Radiology {ACR) and the American Institute of Ultrasound in Medicine (AlUM) provide a pelvic sonogram guideline for sonographers.14 The protocol may be adapted for specific needs of a deparunent, doctor, and/or patient. The representative images obtained and required may vary between facilities. The following protocol contains the minimum views for a normal pelvic exam. Visit the ACR or AIUM web site for a detailed protocol.24 1. Image the cervix in the sagittal and coronal planes. Use the vaginal canal as a landmark for the cervix. 2. Advance the transducer to the fornix of the vagina to examine the uterus in both the long and short axis planes. Be sure to evaluate and scan through the entire organ. Measure on three orthogonal planes. 3. Image and measure the endometrium on the midline sagittal plane. 4. Proceed to evaluate both adnexa by sweeping through each side in the longitudinal and transverse planes. 5. Use spectral, color, and/or power Doppler to identify vascular structures within the pelvis. 6. Capture images of the ovaries demonstrating both long and short axis of each organ, documenting any abnormalities detected in both planes as well. Measure each ovary on three planes. 7. Finally, examine and image the pelvic cul-de-sac for the presence of fluid. Normal anatomic structures such as the ovaries and fallopian tubes, and/or pathology, may be present in this area as well.

Practical nps: How to Improve Endovaginal Scanning Sometimes it is hard to obtain a clear image of the object remote from the transducer head because the endovaginal transducer uses high-frequency ultrasound with poor tissue penetration. The solution to this problem is to bring the transducer head as close as possible to the object. For example, if the ovary is in the cul-de-sac, the transducer should be positioned in the posterior vaginal fornix. When using a frequency-selectable transducer, choose the frequency that allows for adequate penetration and the best detail. When the object is near the vaginal fornix, a high-frequency setting is used. 1b image a structure further from the transducer face, use a low-frequency setting. A closer structure requires less penetration, thus allowing for use of a higher-frequency setting. Consider the pressure to the object by the transducer head. The pressure by the transducer head easily transmits to the object because there is no hard tissue like the abdominal wall in TAS. The pressure of endovaginal ultrasound transducers may temporarily deform soft objects such as an ovarian cyst. In patients complaining of lower abdominal and pelvic pain, palpate the uterus and

• Ensure removal of all air between the sheath and transducer • Use the highest frequency possible for the best detail • Reduce the sector width to increase detail • Image the orpn of interest in the central beam • Position the transducer footprint close to the area of interest • Decrease the depth tD fill the image with the target orpn • Use external maneiM!lrs such as bimanual manipulation or rolling the patient tD bring the area of interest intD range • Color or power Doppler helps ldendfy surrounding WISSels and thus the organ (I.e., ovary) • Ask for help

adnexa with the transducer head. This is an efficient way detect the cause and location of the pain. In patients presenting with abnormal uterine bleeding, for outlining the uterine cavity a negative contrast medium such as saline is used. When the object is far from the vaginal fornix, use bimanual maneuver and push the object toward the vaginal fornix. If it does not work satisfactorily or the object is too big, use TAS or other modalities such as CT or MRI. EVS is powerful in gynecologic examination but not universal.

to

Color and Spectral Doppler Imaging Doppler ultrasound can determine the presence or absence of flow, flow clliection, and flow character.25 One of the fundamental. limitations of flow information provided by the Doppler effects is that it is angle dependent. Furthermore, artifacts in Doppler ultrasound can be confusing and lead to misinterpretation. The Doppler effect consists of a change in frequency of waves that reflect from moving reftectors. The amount of the change of frequency is called Doppler shift and is measured in Hertz. Velocity can be calculated when the angle between ultrasound beam and flow direction is known. Apart from absolute velocity measurement, one can define relative indices, which are particularly useful for flow evaluation without known angle between the ftow and ultrasound beam. Because of inherent difficulties in quantitatively evaluating blood flow, the blood flow velocity waveform has commonly been interpreted to distinguish patterns associated with high and low resistance in the distal vascular tree. Three indices are in common use, the systolic/diastolic ratio (SID ratio), the pulsatility index (PI, also called the impedance index), and the resistance index (RI, also called the Pourcelot ratio). The S/D ratio is the simplest, but it is irrelevant when diastolic velocities are absent and the ratio becomes infinite. An "extremely high"' value would be above 8.0. Definitions of RI and PI are as follows: RI

= S- D/S

PI = S - D/mean

5

Spectral Doppler or pulsed Doppler displays the peak velocity of flow in a vessel. Spectral Doppler presents as either a positive or a negative shift above or below the baseline, indicating the direction of flow within the evaluated vessel. Direction of flow is more important when evaluating larger blood vessels and can be quite challenging for smaller vessels. Each vessel in the body has a spectral waveform expected during the examination. Pulsed Doppler of the pelvic vasculatme may and can vary depending on the menstrual phase of the patient, as will be discussed later in this chapter. Color Doppler demonstrates the average flow frequencies, displayed as a velocity, over time within the specific area examined. Color Doppler also provides directional information, determining whether the flow is toward or away from the transducer. Power Doppler is another option available if color Doppler is not producing the desired effects. Power Doppler is another mode that displays the Doppler shift as color. Unlike color Doppler, where a slow- or low-flow states result in a poor signal, power Doppler uses the strength or amplitude of the signal. This results in an increased sensitivity to low blood flow; thus vessels that produce lower Doppler shifts image with power Doppler. Newer equipment now has the ability to display what is called directional power Doppler; however, standard power Doppler does not represent direction. Power Doppler used as an adjunct to color supplies the sonographer with more valuable diagnostic information. The preset for the pelvic exam is a good starting point for Doppler settings; however, the sonographer has the capability to adjust the pulse repetition frequency or scale, color or pulsed Doppler gain, wall filter, and baseline. 'Itansabdominal and endovaginal imaging may both benefit from the implementation of spectral, color, and power Doppler. Apply these techniques to situations such as ovarian torsion evaluation, adnexal masses, retained products of conception, and ectopic pregnancies. Use of the various Doppler modes has improved the diagnosis of many pelvic abnormalities and emergencies.

FOLLICULARAND LUTEAL BLOOD FLOW With EVS and color flow imaging. it is possible to study subtle vascular changes dming the ovarian cycle in physiologic and pathophysiologic conditions.2.6.2.1 The ovary receives arterial blood flow from two somces: the ovarian artery and the utero-ovarian branch of the uterine artery. These arteries anastomose and form an arch parallel to the ovarian hilum. Characteristic flow signals from the ovarian artery demonstrate low Doppler shifts and blood velocity (Fig. 5-66). The waveform varies with the state of activity of the ovary. Studies of the ovarian artery blood flow velocity waveforms demonstrated a difference in the vascular impedance between the two ovarian arteries, depending on the presence of the dominant follicle or corpus luteum.26.17 Decreased PI and RI reflect decreased vascular impedance and increased flow to the ovary containing the dominant follicle or corpus luteum.2.6 The ovarian artery of the inactive ovary shows low end-diastolic flow or absence of diastolic

NORMAL ANATOMY OF THE FEMALE PELVIS

117

FIGURE 5-66 Blood flow velocity waveronns obtlined from 1he ovarian artery during 1he lu!Eal phase of the menstrual cyde. Note continuous diastolic flow and Rl of 0.82, reflecting inc:reasele cystic degeneration; may result in torsion

Struma ovarii

Teratoma composed of thyroid tissue; increased 1hyroid hormone levels without thyroid disease; age 50

Centralized flow with color Doppler imagi~; solid; ascites

Choriocarcinoma

May cause precocious puberty; aggressive growth; elevated hCG; abdominal enlargement; pain; may

Variable cons5tency; large; unilateral

develop hemoperitoneum; menstrual abnormalities Teratocan:inoma

Rare tumor; often seen in young adulthood

Variable appearance with cystic and highly echogenic areas with acoustic shadow

Endodennal sinus tumor (yolk sac rumor)

Often seen in adolescence; radiosensitive; may be cause of primary arnenormea; AFP elevated; abdominal pain

Pll!dominantly rapidly growi~ solid mass with areas of necrosis; unilateral; large (3-30 em); lymphadenopalhy

METASTASES TO OIAifY (596-1096) Krukenberg tumor

Primary in gastroint:estilill tract or fi'cm ether siles: breast, lung, panaeas, lymphoma; pre- and postmenopausal; may be first manifestation of e:xtr.uMrian malignant disease; search br gastrointeslilal primal)'

l.alie masses; usually complex texture and bilateral; more common on right if unilateral; often indistinguishable from ovarian primary malignancy; ascites Bilateral; solid; hypoechoic

Lymphoma SEX-CORD STROMAL TUMORS (596-IOCJfl) Granulosa-theca cell tumor

Wde age range; assoc:iared with hyperestrinism; vaginal bleedhg O'Mng 1D endomettial hyperplasia or carcinoma; breast tenderness; preaxious puberty; pain CMiirgto torsion; asscx:iated with endometrial and breast carcinOI'Tlil; abdominal pain; hemoperitoneum ~to rupture

Pll!dominantly solid; unilateral; homogeneous; may see endometrial thickeni~; size up to 40 em; periiDneal metastasis common; Meigs syndrome; cystic liver masses

Androblastcma (Sertdi-Leyclig cell tumor)

Common in adolescence; may haw masculinizing efl'ect; may have elevated AFP

Usually solid; unilateral; hypoechoic; small

Arrhenoblastoma

Infertility; amenorrhea; may haw masculinizing efl'ect; ache; hirsutism; high serum te!ilosterone levels

Solid; cystic areas; lobulated; unilateral; well encapsulated; size up to 30 em

AFP. alpha. fetoprotein; CEA. can:ionoembryonic antigen; hCG, human chorionic gonadctropin; IDH, lactate dehydrogenase. "'ncludes transdermal sinus tumor. malignant mixed germ cell rumor. choriocan::inoma, and embryonal card noma.

I0

MALIGNANT DISEASES OF THE OVARY

225

OVARIAN NEOPLASMS

Germ Cell Neoplasms

Epithelial Neoplasms

Germ cell tumors account for 15% to 20% of all ovarian neoplasms. Almost 9S% of these are actually benign and are classified as cystic teratomas. The other small percentage are malignant and include dysgerminomas and endodermal sinus/yolk sac tumors. These occur mainly in children and young adults. Dysgerminomas constitute approximately 3% to 5% of ovarian malignancies. They have a higher cure rate owing to their high sensitivity to radiation. Often occurring in adolescence, they may be the cause of primary amenorrhea. Sonographically, they appear as solid homogenous hyperechoic masses with irregular borders. Color Doppler can demonstrate fibrovascular septa with arterial flow. Although considered rare, yolk sac tumor is the second most common germ cell tumor. It is a rapidly growing ovarian neoplasm and prognosis is usually poor; it is typically found in females less than 20 years of age. An increase of serum alpha fetal protein (AFP) can be associated with yolk sac tumor. The sonographic appearance is similar to a dysgerminoma. Yolk sac tumors are predominantly solid with areas of necrosis and can measure up to 30 em with associated lymphadenopathy.

Epithelial neoplasms represent a large number of ovarian malignancies and are considered the most common form of ovarian cancer. These types of tumors include serous and mucinous cystadenocarcinoma, endometrioid tumor, clear cell, and transitional cell (Brenner tumor). Epithelial neoplasms account for 65% to 75 % of all ovarian neoplasms and nearly 90% of ovarian malignancies. Serous cystadenocarcinomas are the most common epithelial tumors, and although largely benign, account for about SO% of all malignant ovarian neoplasms. Frequently they are found in the postmenopausal patient and occasionally affect the ovaries bilaterally. Sonographically, serous cystadenocarcinomas can vary in size but are typically quite large. They present as cystic masses with multiple thick septations and possible solid papillary projections arising from the walls of the mass. Thick echogenic material may be seen within these loculations. Ascites is typically found in the setting of ovarian carcinoma. Mucinous cystadenocarcinomas are considered another common ovarian malignant neoplasm, but not as common as the serous type. They are also largely found in the postmenopausal patient. These tumors are less likely to be bilateral, but are usually large, multi-loculated cystic masses with papillary projections and thick echogenic material. Mucinous cystadenocarcinomas have a very similar appearance to their serous counterpart, and it can be difficult to determine mucinous versus serous on a sonogram. A condition known as pseudomyxoma peritonei is commonly found with mucinous cystadenocarcinoma. This is seen when mucin-secreting cells fill the peritoneum causing the cavity to fill with a gelatinous material. Sonographically, this can appear as large-volume ascites with septations and low-level echoes. Of note, a ruptured mucocele of the appendix and mucinous tumors of the appendix and colon can also lead to pseudomyxoma peritonei. Endometrioid tumor is a type of undifferentiated adenocarcinoma. Nearly all endometrioid tumors are malignant. They are the second most common type epithelial malignancy, accounting for around 2S% of all ovarian cancerous neoplasms. They can be bilateral, but not as common. There is an association with endometriosis, which can be found within the endometrium, or within either ovary. It presents sonographically as a cystic mass containing papillary projections, also known as mural nodules. Clear cell tumors are considered to be a variant of endometrioid carcinoma, usually occurring after the age of SO. They are almost always malignant and are far less common than the previously mentioned neoplasms, accounting for only S% to 10% of ovarian carcinomas. There is an association with pelvic endometriosis and can arise from the inner lining of an endometrioma. Clear cell tumors present as a predominately cystic complex mass. 'Ii'ansitional cell tumor, also known as Brenner tumor, is uncommon and only accounts for 2% to 3% of all ovarian neoplasms. They can be malignant but almost always benign. Sonographically, they appear as hypoechoic solid masses with possible calcifications in the outer wall.

Sex-Cord Stromal Tumors Sex-cord stromal ovarian tumors account for S% to 10% of all ovarian neoplasms and 2% of all ovarian malignancies. This group of tumors arises from the stromal component of the ovary. Similar to most ovarian neoplasms, their diagnosis is histologic. They are often suspected of malignancy prior to operation, owing to the solidarity of the tumor and which tend to occur most commonly in postmenopausal women. Granulosa cell tumor represents only 2% of ovarian neoplasms and has low malignant potential. Largely found in the postmenopausal patient, they are almost all unilateral. Clinically, an increase in estrogen may occur because they are commonly estrogenically active. This causes an association with endometrial hyperplasia and carcinoma. Sonographically, these tumors can have a variable appearance but are typically solid masses with varying degrees of hemorrhage. Granulosa cell tumor can measure up to 40 em and endometrial thickening may also be seen. If metastases occur, multiple peritoneal masses and cystic liver lesions can be found. Androblastoma, also known as Sertoli-Leydig cell tumor, is another rare ovarian tumor that represents less than 0.5% of ovarian neoplasms. Commonly found during adolescence, malignancy appears in 10% to 20% of these tumors. Clinically, they may cause a masculinizing effect. Sertoli-Leydig cell tumors appear sonographically as unilateral solid hypoechoic masses and are usually smaller in size.

Metastases to the Ovary The most common primary sites of ovarian metastases are to the breast and the gastrointestinal tract. They represent 5% to 10% of ovarian neoplasms. A Krukenberg tumor refers to a malignancy in the ovary that metastasized from a primary site, most commonly gastrointestinal, although it can arise from the breast. Ovarian

226

PART ONE GYNECOLOGIC SONOGRAPHY

metastatic masses are typically bilateral, with complex echogenicity sonographically. They tend to be more commonly found on the right ovary if unilateral and are often indistinguishable from primary ovarian malignancy. Ascites is also typically found.

Pathophysiology A characteristic feature of most epithelial cancers. the most common form of ovarian malignancy, is the tendency to form cystic masses with multiple septa (Fig. 10-1). The masses can be enormous, reaching 30 to 40 em in diameter, weighing 10 to 15 kg, and extending into the abdomen (Fig. 10-2). The cysts contain serous or mucinous fluid. Nodular or papillary growths may project into the cystic fluid or outward on the external surface of the cyst (Fig. 10-3). The tissue is typically friable, and thin-walled blood vessels of the lesion are predisposed to intracystic bleeding. Color Doppler analysis would help demonstrate prominent blood flow in

FIGURE 10-1 This endovagjnal image demonstrates the multiple septations seen with ovarian malignancy. Qmage courtesy of Philips Healthcare, Bothell, WA.)

FIGURE I0-3 Tnis 3D reconstruc:!icn of the internal architecbJre of 1t1e ovarian cyst reveals growth of internal projections extending from the cyst wall. (Image courtesy of Philips Heahhcare, Bothell, WA.)

the septations or solid tissue components with elevated diastolic flow (Fig. 10-4). Areas of the lesion lacking adequate blood supply may suffer necrosis. Bleeding and necrosis add to the fluid content of the lesion, therefore increasing the ultrasound echogenicity of the fluid. Dystrophic calcification often occurs within areas of cellular degeneration. Radiographs demonstrate these microcrystals, or psammoma bodies. The epithelial tumors that do not secrete fluid are usually smaller but may still have irregular fluid collections within them secondary to hemorrhage and necrosis. Associated ascites often occurs with ovarian malignancy. Sixty to seventy percent of postmortem examinations find the typically high-protein ascetic fluid in the abdomen. Protein-rich fluid exudes from the tumor-bearing surfaces of the peritoneum because the vessels are more permeable to protein.25 Fluid accumulates first in the dependent portion of the peritoneal cavity, such as the pelvic cul-de-sac. Subsequently. the fluid ascends into both paracolic gutters but predominantly on the right side because this space is broader and forms a better communication between the right upper quadrant and the pelvis {Fig. 10-5).

Spread and Staging of Ovarian Malignancy

FIGURE 10-1 Imaging of a large, in this case a 30 X 13 an, complex mass extending out d 1t1e pelllis, probably of CMllian ori~n. Qmage courtesy d Philips Healthcare, Bothell, WA.)

The major pattern of metastatic spread of ovarian malignancy is direct extension involving the neighboring organs in the pelvis, peritoneal seeding. and lymphatic spread. Ovarian cancer is the most common tumor responsible for peritoneal malignancy in women. Intraperitoneal dissemination occurs when tumor cells are shed from the lesion and establish growth on peritoneal surfaces within the abdomen, particularly the diaphragmatic leaflets, liver capsule, bowel serosa. and omentwn. This occurs relatively early in the disease and is often. but not always. associated with ascites. Although the pattern of ovarian cancer metastasis is not predictable, there are several pathways for the lymphatic spread of tumor ceUs. These include peritoneal lymphatic drainage toward the diaphragm and pelvic lymphatic drainage to the retroperitoneum. The diaphragmatic lymphatics that drain to the retrostemal and mediastinal nodes constitute a major avenue for spread of the disease to the chest. Because

10 MAUGNANT DISEASES OF THE OVARY

A

227

B

FIGURE lo-4 A: A multiseptated cyst with projec:tions into complex-appearing fluid is a sign of an ovarian malignancy. B: Color Doppler imaging reveals fla.v in the membrane separating 1he complex cystic a.n!QS, Omages courtesy of Philips Healthcare, Bothell, WA)

A

B

c

D

FIGURE 10.5 Meigs syndrome is1he combination d asdtes, pleural effusion, and an ovarian neoplasm. A transli'erse (A) and l01"4!itudinal (B) image of the right upper qJC!drant demor.stmes 1he typical appearance d ascites. Bowel floats wi1t1in 1he ascetic fluid (C) and should not be mistaken for abdominal wall seeding of malignancy. D: Pleural fluid (anwt). Qmages courtesy of Philips Healtttcare, Bottle!!, WA.)

PART ONE GYNECOLOGIC SONOGRAPHY

228

the diaphragmatic lymphatics are the major pathways of peritoneal fluid drainage, blockage of this pathway by an enlarging tumor may also produce ascites. Positive vaginal cytology is owing to advanced cases of ovarian malignancy, antegrade spread, or distal migration of tumor cells to the uterus. Frequently, distant metastases can occur in the liver (Fig. 10-6). Sonographically, these lesions may have a complex cystic appearance, reflecting the presence of fluid and mucin within them. The extent of tumor spread, or stage of disease, at time of diagnosis is an imponant parameter in detei'Illining the patient's clinical course. Staging schemes proposed by the International Federation of Gynecologists and Obstetricians (FIGO) and the American Joint Committee on Cancer (AJCC) are widely accepted (Table 10-3). The stage of disease is determined at the time of laparotomy. Imaging techniques magnetic resonance such as computed tomography imaging (MRI), and ultrasound add further information to increase the accuracy of staging (Fig. 10-7).16-30

ccn.

TABLE I 0-3 Staging System for Ovarian CancerU.lW FIGO Stqe

lA

TNM Stap

Extent el Dl.....

TX

Unable to assess primary rumor

TO

Primary rumor not seen

Tl

Growth limited to the ovaries

Tla. NO, MO

Umited to one avary, capsule intact and free of tumor, no

ascites, negative peritoneal cytology IB

Tlb,NO,MO

Neoplasms found in both ovaries, capsule intact and free of tumor. no ascites, negative peritoneal cytology

IC

Tic, NO,MO

Masses are either lA or IB; however; 1he tumor extends outside the ovarian capsule to the surface, ascites, positive peritoneal cytology

II

T2

IlA

T2a. NO, MO

Growth beyond ovaries but limited to the pelvis

Extension or implants to \JI:ei"Us,,\\Jbe5, no ascites,

negative peritoneal cytology

FIGURE I U This image of tne liver demonstrates the typial hypoechoic appearance c:i metastasis. Note the anechoic asdtes seen in the anterior portion c:i the image. (Image courtesy c:i Philips Healthcare, Bothell, WA)

liB

T2b, NO,MO

Extension to other pelvic structures, including utErus, no ascites, negative peritoneal cytology

IIC

T2c, NO,MO

Pelvic extension or implants similar to IlA or 118, ascites, positive peritoneal cytology

Ill

T3

Growth beyond the pelvis; retroperitoneal or inguinal nodes or intraperitoneal omental implants; superlicial liver metlstlses

lilA

T3a. NO, MO

Negcrtive nodes, histologically confirmed microscopic seeding of alxJominal peritoneal surfaces

1118

T3b, NO,MO

Same as lilA with alxJominal peritoneal implants 2 em diameter or positive pelvic. retroperitoneal, or inguinal nodes

IV

T(any), N(any), M I

Distant metastases or pleural involvement; liver parenchymal metastases

Pleura Diaphragm Liver Serosal bowel Implants

Omentum Stomach

Nodes Ovaries PeiYic peritoneal Implant FIGURE I 0.7 Likely metastatic sites for ovarian cancer:

T. t\mor size: N, spread to nodes: M, metastasis.

10 MAUGNANT DISEASES OF THE OVARY

CLINICAL CONSIDERATIONS Symptoms Ovarian carcinoma is mainly a disease of perimenopausal and postmenopausal women; mean age at diagnosis is 52 years. The often insidious or vague symptoms of ovarian cancer widely contribute to delays in diagnosis. Patient complaints of pressure from an enlarging pelvic mass or from accumulation of ascites will result in related symptoms. Less frequently, manifestation of honnone activity (feminizing or masculinizing symptoms) provides clues to the presence of a lesion. Rarely, the diagnosis is made only when the tumor undergoes torsion and the patient presents with an acute abdomen, requiring surgical intervention. An analysis of clinical studies from the literature disclosed that 95% of women with ovarian cancer reponed symptoms prior to diagnosis. The most common reported symptom is abdominal bloating (77%}, followed by complaints of abdominal pain (58%). 31 The mass may cause backaches, pelvic pressure, or simply a vague feeling of pelvic discomfort. The pressure from an enl;nging mass and ascites accounts for the urinary symptoms of urgency and frequency seen in 34% of patients. It is important to note that despite the usual increase in abdominal girth, some patients may experience true weight loss. Such complaints are often treated symptomatically, diverting attention from the pelvis and delaying diagnosis. Undiagnosed, persistent gastrointestinal symptoms in women older than 40 years of age should prompt investigation for an ovarian lesion. A significant number of patients with ovarian malignancy present with or develop vaginal bleeding. Bleeding may be secondary to estrogen secretion by the malignant lesion, concurrent endometrial and ovarian carcinoma. or direct spread of the lesion to the endometrium, although rare. Most frequently, the cause of bleeding is undetermined. Symptoms of abnormal endocrine activity are sometimes a clue to the presence of an ovarian malignancy that is hormonally active or stimulates the normal ovarian tissue to increased honnone production. Feminizing effects owing to overproduction of estrogen by a granulosa cell tumor are

A

229

often assod.ated with vaginal bleeding in the postmenopausal patient. In young girls, a rare cause of primary amenorrhea is dysgerminoma, which is the counterpart of, and histopathologically resembles, the seminoma of the testis (Fig. 10-8). A lesion that often produces defeminizing or masculinizing effects is the arrhenoblastoma or Senoli-Leydig cell tumor. This lesion occurs in adolescents or young women. Other endocrine-like effects, such as Cushing syndrome, hypoglycemia, hypercalcemia, and hyperthyroidism, may present in association with ovarian malignancy. One consequence of hormonal activity by the ovarian lesion is the possibility of earlier diagnosis. Of note, abnormal hormonal activity is nondiagnostic of ovarian malignancy, as a variety of benign ovarian neoplasms manifest similar abnormalities. Any mass may undergo a sudden compromise of its blood supply as a result of torsion or incarceration. Ovarian malignancy can be incidentally found this way. Such an event is likely to produce acute abdominal symptoms that mimic inflammatory disease. In the pediatric age group, ovarian malignancy is likely to present as a pelvic or abdominal mass, with or without torsion. 1brsion of any ovarian mass is also more likely to occur in the second or third trimester of pregnancy because of uterine enlargement and the change in position of the ovarian pedicle. u

Treatment Early detection of ovarian cancer results in a cure rate of more than 90% with conventional treatment. However, only 25% of ovarian cancers are diagnosed in stage 1.32 'lreatment options include surgery, radiation therapy, and chemotherapy.33 Surgical planning and management begins with appropriate surgical staging and histologic confirmation of the specimen. An attempt to remove the bulk of the tumor, known as debulking, is performed to minimize residual disease and enhance the effectiveness of radiation and chemotherapy. Surgical treatment usually includes bilateral salpingo-oophorectomy, total hysterectomy, and omentectomy. In yoUDg' women with stage I disease, removal of the affected ovary will help preserve fertility. The diagnosis of stage II or stage IV results in a cyclic course

B

FIGURE I 0.8 A: This su,.P e)(311'1ple of a dysgenninoma shows that it is a solid 1Umor with a gray, fleshy. and lobulated cut surface. The lesion is principally solid with some cystic areas. B: The possible sonographic appearance cl the same type of mass. Qmage courtesy of Philips Healtncare, Bothell, WA)

230

PART ONE GYNECOLOGIC SONOGRAPHY

of chemotherapy often paired with radiation therapy. 'Ib determine the presence or absence of residual disease the clinician may recommend a repeat laparotomy to determine recommendation of possible further treatment.

Laboratory Tests Malignant cells in the body have been found to produces substances detectable by a simple blood test. These substances have been termed "rumor markers•., which include proteins. hormones, or enzymes. Ovarian carcinoma results in significant elevations of certain tumor markers; unfortunately none is unique to the ovary or sensitive enough for use as a screening test. However. in a patient with a known suspicious pelvic mass. certain laboratory tests can aid in the diagnosis. Most widely used is the tumor marker known as CA 125. It is utilized clinically as a marker of disease status and. through periodic monitoring. increasing levels can assist in the diagnosis of recurrent ovarian cancer.34 In contrast, a decreasing marker level is indicative of effective therapy. CA 125 is a cell surface glycoprotein present in 80% of ovarian epithelial cancers.~5 It can be used in combination with two other newly identified markers, CA 72-4 and CA 15-3. A simultaneous elevated level of these antigens is predictive of malignant disease in a majority of cases.12•13 However. when used as a screening tool for the detection of early ovarian cancer. the sensitivity of CA 125 is low. If a normal antigen level (l. 2006;49(3):433-447. 11. Fleisher AC, Lyshchik A, Hirari M. Early detection of ovarian cancer with conventional and contrast-enhanced sonography: recent advancee and potential improvements. J Oncol. 2012;ZOIZ:302858. dol:10.1155/2012/302858. 12. Hamilton w; Peters TJ, Bankhead C, et al. Risk of ovarian cancer in women with symptoms in primary care: population based case-control study. BMJ. 2009;339:b2998. dol:10.1136/bmj.b2.998. 13. Schutter EM. Davelaar EM, Van Kamp GJ, et al. The differential diagnostic potential of a panel of tumor markers in patients with a pelvic mass. Am J Obstet Gynewl. 2002;187(2):385-392. 14. Kobel M,. Kalloger SE, Boyd N, et aL Ovarian caiCinoma subtypes are different diseases: Implications for biomarker studies. PLoS

Med. 2008;5(12):e232. IS. Jacobs U, Menon U. Progress and challenges in screening for early detectiOD. of ovarian cancer. Mol CellProteomia. 2.004;3 (4) :355-366. 16. Berkelmane CT. Risk factors and rl.sk reducUon of breast and ovarian cancer. eurr Opin Obstet Gyn«x>l. 2003;15(1):63-68. 17. Poole Em. Merritt MA, Jordan SJ. Hormonal and reproductive risk factors for epithelial ovarian cancer by tumor aggressiveness. cancer Epidenwl Bumuukers Prev. 2013;2.2.(3):429-437. 18. SmithER, Xu XX. Ovarian ageing, follicle depletion, and cancer: a hypothesis for the aetiology of epithelial ovarian cancer involving follicle depletion. Lancet Oru:vL 2.008;9{11):1108-1111.

I0

19. Tchagang AB, Tewfik AH, DeRycke M8, et al. Early detection of ovarian cancer using group biomarkers. Mol Cancer Ther. 2008;7(1):27-37. 20. 1bgashi K. Ovarian cancer: the clinical role of US, CT, and MRI. Eur Radiol. 2003;13(4):L87-L104. 21. Genetics Home Reference. Available at: http://ghr.nlm.nih.gov1. Accessed January, 2010. 22. Thefferd M, Couturier J, Penault-Llorca F, et al. HER2 status in ovarian carcinomas: a multicenter GINECO study of 320 patients. PLoS One. 2007;2(1l):el138. 23. Schildkraut JM, Abbott SE, Alberg AJ. Association between body powder use and ovarian cancer: the African American cancer epidemiology study. Epidemol Biomarkers Prell. 2016;25(10): 1411-1417. doi 10.1158/1055-9965. 24. World Health Organization. Classification of human ovarian tumors. Environ Health Perspect. 1987;73:15-25. 25. Wang E, Ngalame Y, Panelli MC, et al. Peritoneal and subperitoneal stroma may facilitate regional spread of ovarian cancer. Clin Cancer Res. 2005;11(1):113-122. 26. deSouza NM, O'Neill R, Mcindoe GA. et al. Borderline tumors of the ovary: CT and MRI features and tumor markers in differentiation from stage I disease. AmJ Roentgenol. 2005;184(3):999-1003. 27. van Nagell JR. Jr, DePriest PD. Reedy MB, et al. The efficacy of endovaginal sonographic screening in asymptomatic women at risk for ovarian cancer. Gynecol OncoL 2000;77(3):350-356. 28. Spencer JA. A multidisciplinary approach to ovarian cancer at diagnosis. Br J Radial. 2005;78(spec no 2):894-8102. 29. Outwater E, Dressel HY. Evaluation of gynecologic malignancy by magnetic resonance imaging. Radio! Clin NorthAm. 1992;30(4) :789-806. 30. Sanders RC, McNeil BJ, Finberg HJ, et al. A prospective study of CT and US in the detection and staging of pelvic masses. Radiology. 1983;146(2):439-442. 31. Goff BA, Mandel LS, Melancon CH, et al. Frequency of symptoms of ovarian cancer in women presenting to primary care clinics. lAMA. 2004;291(22):2705-2712. 32. Bast RC. Status of tumor markers in ovarian cancer screening. J Qin Oncol. 2003;21(10 suppl):200s-205s. 33. Morrow CP. Malignant and borderline epithelial tumors of ovary: clinical features staging diagnosis. Intraoperative assessment and review of management. In: Coppleson M, ed. Gynecologic Oncology: Fundamental Principles and Qinical Practice. Vol2. New York: Churchill Livingstone; 1981:655-679. 34. Rieber A, Nussle K, Stohr I, et al. Preoperative diagnosis of ovarian tumors withMRimaging. AmJRoentgenol. 2001;177(1):123-129. 35. Myers ER, Bastian LA, Havrilesky l.J, et al. Management of adnexal mass. Evid. Rep 7echnol Assess (FllU Rep). 2006;(130):1-145. 36. Van Calster B, Timmerman D, Bourne T, et al. Discrimination between benign and malignant adnexal masses by specialist ultrasound examination versus serum CA-125. JNatlCancer Inst. 2007;99(22):1706-1714. 37. Neesham D. Ovarian cancer screening. Aust Fam Physician. 2007;36 (3):126-128. 38. Rumack CM, Wilson SR, Charboneau JW. Gynecologic ultrasound. In: Arnold CF, ed. Diagnostic Ultrasound.. 3rd ed. Voll. St. Louis: Elsevier; 2006. 39. Mills SE. Sternberg's Diagnostic Surgical Pathology. 5th ed. Vol2, Chapters 54 and 55. Baltimore: lippincott Williams & Wilkins; 2010. 40. Iyer RB, Balachandran A, Devine CE. PET/CT and cross sectional imaging of gynecologic malignancy. Cancer Imaging. 2007;7(spec no A):Sl30-S138. 41. Valentin L, Callen PW. illtrasound evaluation of the adnexa (Ovary and Fallopian 1\Jbes). In: Peter WC, ed. Ultrasonography in Obstetrics and Gynecology. 5th ed. Philadelphia: Saunders Elsevier; 2008. 42. Thomas M, Van Vom:jis BJ. Gynecologic ultrasound. In: Gibbs RS, Karlan BY, Haney AF, et al, eds. Danforth's Obstetrics & Gynecology. lOth ed. Philadelphia: Lippincott Williams & Wilkins; 2008.

cancer

MALIGNANT DISEASES OF THE OVARY

239

43. Sherman ME, Lacey JV. Buys SS, et al. Ovarian volume: determinants and associations with cancer among postmenopausal women. Cancer EpidemiolBiomarkers Prell. 2006;15(8):1550-1554. 44. Hagan-Ansert S. The sonographic and Doppler evaluation of the female pelvis. In: Sandra LH, ed. Jextbook of Diagnostic Medical Ultrasonography. 6th ed. Vol2. St. Louis: Mosby; 2006:873-897. 45. Kushtagi P, Kulkarni KK. Significance of the 'ovarian crescent sign' in the evaluation of adnexal masses. Singapore Med J. 2008;49(12): 1017-1020. 46. Liu J, Xu Y, Wang J. illtrasonography, computed tomography, and magnetic resonance imaging for diagnosis of ovarian carcinoma. Eur J Radiol. 2007;62(3):328-334. 47. Healy DL, Bell R, Robertson DM, et al. Ovarian status in healthy postmenopausal women. Menopause. 2008;15(6):1109-1114. 48. Wallace WH, Kelsey TW. Ovarian reserve and reproductive age may be determined from measurement of ovarian volume by transvaginal sonography. Humnn Reprod. 2004;19 (7) :1612-1617. 49. Kwjak A, Prka M, Arenas JM, et al. Three-dimensional ultrasonography and power Doppler in ovarian cancer screening of asymptomatic peri- and postmenopausal women. Croat Med J. 2005;46(5):757-764. 50. Alclzar JL. Thmor angiogenesis assessed by three-dimensional power Doppler ultrasound in early, advanced, and metastatic ovarian cancer: a preliminary study. Ultrasound. Obstet Gynecol. 2006;28(3):325-329. 51. Shwayder JM. Pelvic pain, adnexal masses, and ultrasound. Semin ReprodMed. 2008;26(3):252-265. 52. Van Holsbeke C, Domali E, Holland TK, et al. Imaging of gynecological disease (3): clinical and ultrasound characteristics of granulosa cell tumors of the ovary. Ultrasound Obstet Gynecol. 2008;31(4):450-456. 53. Ueland FR. DePriest PD. Pavlik EJ, et al. Preoperative differentiation of malignant from benign ovarian tumors: the efficacy of morphology indexing and Doppler flow sonography. Gynecol Oncol. 2003;91(1):46-50. 54. Cohen LS, Escobar PF, Schann C, et al. Three-dimensional power Doppler ultrasound improves the diagnostic accuracy for ovarian cancer prediction. Gynecol Oncol. 2001;82[1):40-48. 55. Kurjak A, Kupesic S, Sparac V, et al. The detection of stage I ovarian cancer by three-dimensional sonography and power Doppler. Gynecol Oncol. 2003;90[2):258-264. 56. Fleischer AC, Lyshchik A, Andreotti RF. Advances in sonographic detection of ovarian cancer: depiction of tumor neovascularity with microbubbles. Am J Roentgenol. 2010;194:343-348. 57. Moyle JW, Rochester D, Sider L, et al. Sonography of ovarian tumors: predictability of tumor type. AmJ Roentgenol. 1983;141(5):985-991. 58. Requard CK, Mettler FA, Jr, Wicks JD. Preoperative sonography of malignant ovarian neoplasms. Am J Roentgenol. 1981;137(1):79-82. 59. Sassone AM, Timor-1Htsch IE, Artner A, et al. Endovaginal sonographic characterization of ovarian disease: evaluation of a new scoring system to predict ovarian malignancy. Obstet Gynerol. 1991;78(1) :70-76. 60. Khan 0, Wiltshaw E, McGready VR, et al. Role of US in the management of ovarian carcinoma. J Royal Soc Med. 1983;76(10) :821-827. 61. Nocera RM, Fagan CJ, Hernandez JC. Cystic parametrial fibroid mimicking ovarian cystadenoma. J Ultrasound Med. 1984;3 (4): 183-187. 62. Nelson BE, Rosenfield AT, Schwartz PE. Preoperative abdominopelvic computed tomographic prediction of optimal cytoreduction in epithelial ovarian carcinoma. J Clin Oncol. 1993 ;11 (1): 166-172. 63. Akin 0, Sala E, Moskowitz CS, et al. Perihepatic metastases from ovarian cancer: sensitivity and specificity of CT for the detection of metastases with and those without liver parenchymal invasion. Radiology. 2008;248(2):511-517. 64. Sohaib SA, Reznek RH. MR imaging in ovarian cancer. Cancer Irruzging. 2007;7(spec no A):S119-Sl29.

- ...

.

.

...

··;'./,:

.

Pelvic Inflammatory Disease and Endometriosis

OBJECTIVES

KEY TERMS

• Describe the etiology, clinical p~entation, and management of pelvic inflammatory disease (PI D) and endometriosis

pelvic inOammatory disease adenomyosis endometriosis

• Discuss the role of ultrasound in diagnosis and management of PID and endometriosis • Classify the severity of PID and endometriosis using current staging categories • Summarize the differences between endometriosis and adenomyosis

GLOSSARY

Adenompsis Presence of endometrial glands and tissues found in the uterine wall Dysmenorritea Painful menstruation Dyspareunia Painful intercourse Endometriosis Implants of endometrial tissue outside the uterus Endometrioma Blood-filled cyst located on the ovary that is the result of endometriosis Endometritis Bacterial infection of the endometrium with potential extension into the

surrounding (parametriaQ tissues

Fitz-Huah-Curtis syndrome (aka perihepatitis) Rare complication of PID resulting in the development of liver adhesions owing to the inflammatory exudates Myometritis Myometrial inflammation Oophoritis Infection of the ovaries Parametritis Infection of the connective tissue surrounding the uterus Pelvic inflammatory disease (PI D) Infection of the female reproductive tract Pyosalpinx Pus within the fallopian tube Peritonitis Infection ofthe peritoneum Salpinaftls Infection ofthe fallopian tube Tubo-ovarlan abscess (TOA) Infection found in the late stages ofPID resulting in the inability to differentiate tubal and ovarian structures Tubo-ovarian complex Ability to identify the avary and tube in the presence of adhesions or infection

D

iffuse morphologic and vascular changes occur in the female pelvis in the presence of pelvic inflammatory disease (PlD) and endometriosis. Both display a varied pattern of tissue involvement and clinical findings. Clinical presentation in the early stages of both disease entities may be nonspecific. Endometriosis often mimics functional

bowel disease, and PID can mimic an ectopic pregnancy or appendicitis. Though physiologically distinct, they exhibit similar sonographic findings. Attention to the details of the patient history and clinical findings in conelation with pelvic ultrasound findings allow the careful clinician to distinguish between PID and endometriosis. In this chapter, we consider 2) shown in an axial plane on T2-weighted MRI. (From Dun nick R. Sandier C, Newhouse J. Textbook of Urarodiolagy. 5th eeL Philadelphia: Wolters Khmer. 2012. Figure 18-36.)

Usually, the uterus is tilted anteriorly (anteversiDn) (see Fig. 13·9). An acute angulation in the mid portion is known as ante{lexton when tilted anteriorly. A posterior tilt of the

A

B

FIGURE 13·12 Adenomyosi5. A: SagitmJ TI-weiitrt:ed image of the uteru5 demonstrating a thickened junctional zone typic:31 of adenomyosis (asterisks). (From Ges.mnionicity and dlorionicity for multiple gesta'tions Nuchal translucency measurement

be dearly distinguished from 1he amnion. A:. Nonnal NT. B: M enlarged NT.

Correct placement

1

- +- ---- - -.

+- - - +

FIGURE 15-ll Only 1he first pair of calipers in 1his diagram shaws correct placement when measuring the NT. (Source: http://www.aium.org /publications!guidelines/obstetric.pdf. Reproduced with pennission from the American Institute of Ultl'liSOund in Medicine.)

PRIMUM NON NOCE.RE.: APPLYING THE ALARA PRINCIPLE IN THE FIRST TRIMESTER Medical students and other students in health care professions are taught, "Primum non nocere." or "First, do no harm... Sonographers and sonologists should apply the as low as reasonably achievable (ALARA) principle during

• •

Documentation

•

of cardiac activity ("'viability')

•

Amnionicity and chorion icity for multiple

•

gestations

•

Nuchal

• •

(CRL, BPD) NT screening

• • • • •

•

measurement Nasal bone measurement

(If requested)

•

Cranial

When technically feasible: • Body contour • Cranial shape

anatomy

•

Neck Spine Thorax Heart Abdominal

•

hsessmentof fetal anaiDmy

•

Nuchal transIucency

measurement

hsessmentof gestational age

Fetal number Crown-rump length Documentation of cardiac activity ('viability") Amnionicity and chorionicity for multiple

gestations

•

trar~slucency

•

FIGURE 15-ll Correct measurement of1he NT. These images display the correct plane and appropriate magnification for measuring the NT, which can

Fetal number Crown-rump length

• •

corrtEnt

•

Facial profile Central nervous system Heart Umbilical cad insertion site Extremities

every sonogram they perform. This is especially true during the first trimester of pregnancy, when development of the embryo or early fetus is at its highest risk of being disrupted. Nevertheless, recent studies show that most sonographers and sonologists do not understand how to implement the ALARA principle during obstetric sonograms.49.SO The potential for unwanted bioeffects during a diagnostic ultrasound examination is affected by the duration and level of exposure. lfltrasound is a fonn of mechanical energy, and therefore has the potential to cause damage to cells containing pockets of gas. In addition, as {ultra)sound waves pass through a medium, some of the energy is converted to heat, which can also be harmful to cells.

348

PART TWO OBSTETRIC SONOGAAPHY

The U.S. Food and Drug Administration's (FDA) Center for Devices and Radiological Health requires ultrasound machines with the capability of producing excessive acoustic output to display indices showing whether the ultrasound exposure during a given exam is within acceptable limits. These displays are the mechanical index {MI) and the thennal index (TO.50 Because it is unlikely that the embryo or fetus contains gas bodies, the index of greatest interest during obstetric scanning is the TI. There are three thermal indices, two of which have applications in obstetric scanning. These are the TI for soft tissue (TIS), and the TI for structures near bone (TIB}. The TI for cranial bone (TIC} is used when the transducer is right up against bone, and therefore is not used during fetal scanning. The operator must select the appropriate TI and modify it as needed. In the early first trimester, before

mineralization of bone occurs, the TIS should be selected. Because bone absorbs heat, sensitive adjacent tissue including brain and spinal cord may also be subject to heating. Therefore, TIB should be selected from 10 weeks gestational age onwarcl.51 -s~ The MI and TI can change over the course of an exam. They are affected by factors including output levels, transducer frequency, pulse repetition rates, and scan modes. At otherwise identical settings, the lowest exposures occur during B mode and M mode scanning. Exposure increases with the use of color Doppler, and is even higher when spectral Doppler is applied. Therefore, Doppler should not be used in the first trimester unless there is a clinical indication to do so.54"56 In serving their patients, sonographers and sonologists must apply these developments in the safest manner possible.

SUMMARY

• Pregnancy consists of three trimesters, dividing the normal 40-week pregnancy into 12-week sections. The first trimester begins at week 1 ending at week 12, the second begins at week 13 ending in week 27, and the third begins at week 28 and ends at delivery. A pregnancy that is undelivered by 42 weeks is considered postterm. • Meiosis results in a haploid germ cell. When the sperm and ovum unite, a single diploid cell, the zygote, results and divides via mitosis. • Cells continue to divide, creating the morula, a ball of cells, as it moves through the fallopian tube (it is already a blastocyst by the time it reaches the uterus). • Once a fluid-filled cavity forms, the structure becomes the blastocyst, which contains the trophoblast, blastocele, and embryoblast. • Disintegration of the zona pellucid allows the blastocyst to begin implantation into the endometrium during the 4-day implantation window 6 to 8 days postovulation. • The syncytiotrophoblast produces hCG, extending the progesteron~secreting corpus luteum. • Placental hormone production includes chorionic gonadotropin, estrogen, and progesterone. • A urine pregnancy test is qualitative; the blood test is quantitative. • The three layers of the decidualized endometrium are the deciduas basalis, capsularis, and parientalis. • The first sonographic evidence of an intrauterine pregnancy is the intradecidual sign, which may be seen as early as 3 weeks, 4 days gestational age. The double sac sign appears at about 7 weeks gestational age. • The first structure sonographically seen within the gestational sac is the secondary yolk sac (secondary umbilical vesicle) that connects to the embryonic midgut via the vitelline duct • The umbilical vesicle produces the embryo's first blood cells, while the allantois become the umbilical arteries. • At 5 weeks gestational age, the internal diameter of the yolk sac/umbilical vesicle is approximately 2.3 nun,

•

• • • • •

• •

and by 11 weeks, it measures 5.6 uun. The yolk sac is eventually incorporated into the embryonic gut, and is no longer detected by 12 weeks. Chorionic villi at the site of the placenta become the chorion frond.osum, eventually forming the fetal portion of the placenta. Chorionic villi not associated with placental development disappear, leaving a smooth chorion laeve, the chorionic membrane. By 6 weeks gestational age, a 2-to-4 mm embryo may be visualized adjacent to the yolk sac within the gestational sac. The primitive heart begins to beat at 23 days. Neural structures imaged include the neural tube, rhombencephalon, and choroid plexus. Limb buds appear at 8 weeks, whereas hands and feet image at 10 weeks. Midgut herniation occurs at 8 weeks and recedes by 12 weeks. First-trimester measurements to establish gestational age include the MSD and the more accurate CRL. The NT, when used in conjunction with biochemical markers, is an effective screening tool for Down syndrome. CRITICAL THINKING QUESTIONS

1. View the following first-trimester study: Using the AlUM or ACR promcol standards, analyze this

study for improvement.

A

15 THE USE OF ULTRASOUND IN lHE ARST TRIMESTER

c

B

D

F

H

MEDIA MENU

Student Resources available on • Audio glossary • Interactive question bank • Videos • Internet resources

Point' include:

349

350

PART TWO

OBSTETRIC SONOGRAPHY

REFERENCES L Moore KL, Persaud TVN. Fiist week of human developmen t. In: Moore KL, Persaud lV, eds. The Developing Human: Clinically Oriented Embryology. lOth ed. Philadelphia : Saunders Elsevier, 2010:11-36. 2. Diedrich K, Fauser BCJM, Devroey P, et al. The role of the endometrium and embryo in human implantation. Hum Reprod Update. 2007;13:365-377. 3. Labied s, Kajlhara T, Madureira P, et al. Progestins regulate the expression and activity of the forkhead transcription factor FOXOl in differentiating human endometrium. Mol Biol. 2006;20: 35-44. 4. Maruyama T, Yoshimura Y. Molecular and cellular mechanisms for differentiation and regeneration of the uterine endometrium . Endocrine J. 2008;55:795-810. 5. Kennedy TG, Gillio-Meina C, Phang SH. Prostaglandi ns and the initiation of blastocyst implantation and decidualization. Reprodnction. 2007;134:635-643. 6. JauniauxE, Johns J, Burton GJ. The role of ultrasound imaging in diagnosing and investigating early pregnancy failure. Ultrosound Obstet Gynecol. 2005;25:613- 624. 7. Moore KL, Persaud lVN. Second week of human development. In: Moore KL, Persaud TV, eds. The Developing Human: Clinically Oriented Embryology. lOth ed. Philadelphia: Saunders Elsevier, 2010; 39-50. 8. Chama CM, Marupa JY, Obed JY. The value of the secondary yolk sac in predicting pregnancy outcome. J Obstet Gynecol. 2005;25:245-247. 9. Takashina T. Haemopoies is in the human yolk sac. J Anat. 1987;151:125-135. 10. Moore KL, Persaud TVN. Third week of human development . In: Moore KL, Persaud TV, eds. The Developing Human: Clinically Oriented Embryology. lOth ed. Philadelphia : Saunders Elsevier; 2010: 51-68. 11. Moore KL, Persaud TVN. The placenta and fetal membranes. In: Moore KL, Persaud TV, eds. The Developing Human: Clinically Oriented Embryology, lOth ed. Philadelphia: Saunders Elsevier, 2010; 107- 140. 12. Wong HS, Cheung YK, Taits J . Sonographic study of the decidua basalis in the first trimester of pregnancy. llltrosound Obstet Gynerol. 2009;33:634- 637. 13. Cao Z, Rej R. Are laboratories reporting serum quantitative hCG results correctly? Clin Chern. 2008;54:761-764. 14. Azzazy HE, Romero LF, Hall L, et al. Two-center clinical evalua~on of a new automated flourometric immunoassa y for the quantitative analysis of total beta-human chorionic gonadotropin . Clin Biochem. 2003;36:523 -528. 15. Ajubi NE, N!jholt N, Wolthuis A. Quantitative automated human chorionic gonadotropin measuremen t in urine using the Modular Analytics E170 module (Roche). Clin Chern Lab Med. 2005;43:68-70. 16. Cole LA, Khanlian SA. The need for a quantitative urine hCH assay. Clin Biochem. 2009;42:67~683 . 17. Grossman D, Berdlchevsk y K, Larrea F, et al. Accuracy of a semi-quantitative urine pregnancy test compared to serum beta-hCG measurement: a possible screening tool for ongoing pregnancy after medication abortion. Contraception. 2007;76:101-104. 18. Checkm, Weiss RM, Lurie D. Analysis of serum human chorionic gonadotropi n levels in normal singleton, multiple and abnormal pregnancies. Hum Reprod. 1992 ; 7:11 7~1180. 19. Shamonki MI, Fratterelli JL, Bergh PA, et al. Logarithmic curves depleting Initial level and rise of serum beta human chorionic gonadotropin and live delivery outcomes with in vitro fertilization: An analysis of 6021 pregnancies. Fertil Steril. 2009;91: 1760- ~764. 20. Barnart KT, Sarnmel MD, Rinaudo PF, et al. Symptomatic patients with an early viable intrauterine pregnancy: hCG curves redefined. Obstet Gynecol. 2004;104:50- 55. 21. Feldkamp CS, Pfeffer WH. The measuremen t of human chorionic gonadotropi n for p regnancy testing. Henry .Rm:l Hosp Med J. 1982;30:207- 213. 22. Braunstein GD, Rasor J, Danzer H, et al. Serum human gonadotropin levels throughour normal pregnancy. Am J Obstet Gynecol. 1976;15:678- 681. 23. Yeh H-C, Goodman JD. Carr L, et al. Intradecidual sign: A US criterion of early intrauterine pregnancy. Radiology. 1986;161 :463-467. 24. Yeh HC. Efficacy of the intradecidual sign and fallacy of the double decidual sac sign in the diagnosis of early intrauterine pregnancy. Radiology. 1999;210:579- 581.

25. Chiang G, Levine D, Swire M, et al. The intradecidua l sign: Is it reliable for diagnosis of early intrauterine pregnancy? Am J RoentgerwL 2004;183:725-731. 26. Yeh HC. Some misconcepti ons and pitfalls in ultrasonogra phy. Ultrasound Q. 2001;17:129-155. 27. Bradley WG, Fiske CE, Filly RA. The double sac sign of early intrauterine pregnancy: Use in exclusion of ectopic pregnancy. Radiology. 1982;143:223-226. 28. Sawyer E, Jurkovlc D. mtrasonography in the diagnosis and management of abnormal early pregnancy. Clin Obstet Gynecol. 2fXY1;1:31- 54. 29. Yeh H, Rabinowitz J. Amniotic sac developmen t: Ultrasound features of early pregnancy- the double bleb sign. Radiology. 1988;166:97- 103. 30. Kurjak A, Pooh R.K, Merce LT, et al. Structural and functional early human developmen t assessed by three-dimen sional and four-dimensi onal sonography. Fertil Sterll. 2005;84:1285-1299. 31. Benoit B, Hafner T, Kurhalt A, et al. Three-dimen sional sonoembryology. J Perinatal Med. 2007;30:63-73. 32. Timor-nitsc h IE, Peisner DB, Raju S. Sonoembryo logy: An organ-orient ed approach using a high-frequency vaginal probe. J Clin llltrosound. 1990;18:286- 298. 33. American College of Obstetricians and Gynecologists. ACOG Practice Bulletin: Intrapartum fetal heart rate monitoring: nomenclatur e, interpretation, and general management principles. Obstet Gynerol. 2009;114:192-202. 34. Jurkovic D, Gruboeck K, Campbell S. Ultrasound features of normal pregnancy development. Curr Opin Obstet Gynerol. 1995;7:493-5~. 35. Blaas H-G, Eik-Nes SH. Sonoembryo logy and early prenatal diagnosis of neural anomalies. Prenatal Diagn. 2009;29:312-325. 36. Kim MS, Jeanty P, Thrner C, et al. Three-dimen sional sonographic evaluations of embryonic brain development . J llltrosound Med. 2008;27:119-124. 37. Hata T, Manabe A, Aoki S, et al. Three dimensional sonography in the early first-trimester of human pregnancy: Preliminary study. Hum REprod. 1998;13:740 -743. 38. Blaas H-G, Eik·Ness SH, Kiserud T, etal. Early development of the abdominal wall, stomach and heart from 7 to 12 weeks of gestation: a longitudinal study. Ultrasound in Obstet Gyneml. 1995;6:240-249. 39. Achiron R, Soriano S, llpitz S, et al. Fetal midgut herniation into the umbilical cord: Improved definition of ventral abdominal anomaly with the use of transvaginal sonography. Ultmsound Obstet Gynecol. 1995;6:256-260. 40. Van Zalen-Sprock RM, Van Vugt JMG, Van Geijn HP. First-trimeste r sonography of physiological midgut herniation and early diagnosis of omphalocele . Prenatal Diagn. 1997;17:511-518. 41. Filly RA, Hadlock FP. Sonographic determinatio n of menstrual age. In: Callen PW, ed. Ultrosonography in Obstetrics and Gynecology. 4th ed. Philadelphia: W.B. Saunders; 2000: 1~170. 42. Salomon U, Bernard M, Amarsy R, et al. The impact of crown-~mp length measuremen t error on combined Sown syndrome screerung: a simulation study. Ultrosound Obstet Gynerol. 2009;33:50~511. 43. Szabo J, Gellen J. Nuchal fluid collection in trisomy-21 detecte4d by vaginosonog raphy. Lancet. 1990;2:1133. 44. Cullen MT, Gabrielli S, Green JJ, et al. Diagnosis and significance of cystic hygroma in the first trimester. Pretwtal Di.agn. 1990;10:643-651. 45 . Cuckle HS, van lith JMM. Appropriate biochemical parameters in first-trimester screening for Down syndrome. Prenatal Diagnosis. 1999;19:505-512. 46. American Institute of illtrasound in Medicine. AlUM Practice Parameter for the PerforrntJIICf! of Obstetric Ultrasound Examinations. Laurel: American Institute of illtrasound in Medicine. 2016. 47. ISUOG. Internationa l Society of illtrasound in Obstetrics and Gynecology Practice Guidelines: performance of first trimester fetal ultrasound scan. Ultrosound Obstet GynecoL 2013;41:102-113. 48. Bromley B, Shipp T, Lyons J, et al. Detection of fetal structural anomalies in a basic first-trimester screening program for aneuploidy. J UltrasoundMed. 2014;33:1737-1745. 49. American College of Obstetrician s and Gynecologis ts. ACOG Practice Bulletin: Screening for fetal chromosoma l abnormalities. Obstet Gynecol. 2007;109:217-227. SO. She!ner E, Shoham-Vardi I, Abramowicz JS. What do clinical users know regarding safety of ultrasound during pregnancy? 1 Ultrasound Med.. 2007;26:319- 325. 51. She!ner E, Abramovicz JS. Clinical end users worldwide show poor knowledge regarding safety issues of ultrasound during pregnancy. J Ultrasound Med. 2008;27 :499- 501.

15 THE USE OF ULTRASOUND IN THE FIRST TRIMESTER

52. U.S. Department of Health and Human Services Food and Drug Administration Center for Devices and Radiological Health. Infvmza-

tion for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and 'Ihznsducers. Rockville: Food and Drug Administration; 2008. 53. Abramovicz JS, Barnett SB, Duck FA, et al. Fetal thermal effects of diagnostic ultrasound. J Ultrasound Meet. 2008;27:541-559. 54. Nelson TR, Fowlkes JB, Abramovicz JS, et al. Ultrasound biosafety considerations for the practicing sonographer and sonologist. J Ultrasound Med. 2009;28:139-150.

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55. Sheiner S, Freeman J, Abramovicz JS. Acoustic output as mea-

sured by mechanical and thermal indices during routine obstetric ultrasound examinations. J Ultrasound Med. 2005 ;24: 1664-1670. 56. Sheiner E, Shoham-Vardi I, Pombar S, et al. An increased thermal index can be achieved when performing Doppler studies in obstetric sonography. J Ultrasound Med. 2007;26:71-76.

Sonographic Evaluation of First-Trimester Complications PAULA WOLETZ

OBJECTIVES

KEY TERMS

• Describe the indications for diagnostic ultrasound in the tim trimester

aneuploidy threatened abortion anembrpnic pregnanc:.y retained products of conception (RPOC) subchorionic hemontaage hydatidifonn mole

• Distinguish the sonographic findings of normal early pregnancy from those of early pregnancy failure, spontaneous abortion, and molar pregnancy • Discuss the use of ultrasound to screen for chromosomal abnormalities and identify structural abnormalities in the fim trimester

GLOSSARY Abortion The spontaneous or induced termination of an early pregnancy and expulsion of fetal and placental tissues

Amniocentesis An invasive procedure in which a quantity of amniotic fluid is removed from the amniotic sac for analysis of the fetal cells or for the presence of certain chemicals in the fluid itself. Amniocentesis may also be performed as a palliative measure in patients with severe polyhydramnios. Anembryonlc presnancy A pregnancy which has failed prior to the development of an identifiable embryo, or in which embryonic tissue has been resorbed after early embryo demise Anemia A deficiency of red blood cells Blighted ovum The empty gestational sac seen in an anembryonic pregnancy Bradycardia An abnormally slow heart rate Chorionic 'Villus sampling An invasive procedure in which the chorionic villi of an early pregnancy are removed for analysis Complete hydatidiform mole Abnormal fertilization of an oocyte that contains no matemal dlromosomes, resulting in the proliferation of swollen chorionic villi and the absence of identifiable embryonic structures Gestational t:Nphoblastlc disease A spectrum of disorders that begins at fertilization and involves abnormal proliferation of the trophoblasts that in a normal pregnancy would have gone on to form the placentl. Gestational trophoblastic disease may become invasive and malignant and metastasize. Gestational trophoblastic neoplasia The invasive or metastrtic form of gestational trophoblastic disease Hydatidifonn mole A form of gestrtional trophoblastic disease resulting from abnormal fertilization, in which there is proliferation of swollen chorionic villi; also called a molar pregnancy Hyperemesis Excessive vomiting. Hyperemesis during pregnancy is sometimes called hyperemesis gravidarum (continued)

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PART TWO OBSTETRIC SONOGAAPHY

Hyperthyroidism Excessive activity of the thyroid Incomplete abortion A spontaneous abortion in which some products of conception remain in the uterus lneviable abortion A failed early pregnancy that is in the process of being expelled from the uterus Milcarriap The spontaneous failure and expulsion of an early pregnancy Milled abortion M early failed pregnancy that remains in the uterus Molar pre1nancy Hydatidiform mole Partial hydatidiform mole Abnormal fertilization resulting in one maternal and two paternal sets of chromosomes (triploidy), leading to the development of an abnormal fetus and placenta Respiratory insufficiency Inadequate absorption of oxygen and/or inadequate expulsion of carbon dioxide Subchorionic hemorrhap A aescent-shaped sonolucent collection of blood between the gestational sac and the uterine wall Subchorionic hematoma Subchorionic hemormage Tac:flralnlla Abnormally rapid heart rate Threatened abortion, d'lreatened mlscarrlqe Vaginal bleeding in a pregnancy of less than 20 weeks; may be accompanied by pain or cramping Theca lutein c,sts Large, often bilateral ovarian cysts, the formation of which is usually stimulated by excessive levels of circulating hCG Taxemia or prepancy Pregnancy-induced hypertension, proteinuria, edema, and headache (preeclampsia), which may progress to the development of seizures (eclampsia) Triploid, triploicly Having three copies of each dlromosome

W

hen a patient repons a problem during the first trimester of pregnancy, or when the clinician perceives an unusual or discrepant finding, ultrasound is often the method of choice to confirm or rule out the clinician's suspicions. This discussion focuses first on the most commonly presenting clinical symptoms in the first trimester. This is followed by the expanded criteria to predict pregnancy viability, findings that raise the suspicion of chromosomal abnormalities, and the early detection of structural anomalies.

outcome of the pregnancy, but in the ability to predict which pregnancies will continue successfully to term. Hasan et al. noted that light bleeding or spotting is unlikely to affect the outcome of the pregnancy, whereas pregnancies complicated by heavy bleeding were three times as likely to result in

EARLY PREGNANCY FAILURE Vaginal bleeding in a pregnancy ofless than 20 weeks is called a threatened abortion or threatened miscarriage (Fig. 16-1). It is a common complication of pregnancy, and as many as 15% to 27% of pregnancies are complicated by one or more episodes of vaginal bleeding in the first 20 weeks. Bleeding may be characterized as spotting (frequently occwring at the time of implantation), may be light, or heavy, and can originate in the uterus, the cervix, or the vagina..I-6 In a desired intrauterine pregnancy, it is important to define specific findings and appropriate follow-up to determine the likelihood that the pregnancy will continue to the point of viability. Although factors unrelated to the pregnancy may be the source of the bleeding, first consideration goes to establish· ing the viability of the pregnancy. The value of ultrasound in threatened abortion lies not in any endeavor to alter the

FIGURE 16-1 Ultrasound sho.Ning multiple vesicular endcmetrial ~ consistent with a~ molar~· A 26-ytar-old presented at I 0 wee:ks ges!3tion with i~lar~nal bleeding. Serum hCG was 120,000 miUhnL. (From BerekJS, Hacker NF. Berek and Hadtr!r's ~~· 61h ed. Phladelphia: V\blters Kluwer. 2014: Figure 15-1.)

16 SONOGRAPHIC EVALUATION OF FIRST-TRIMESTERCOMPLICAllONS

A

355

B

FIGURE 16·1 A: Transabdominal image of a blighted owm. B: Endowginal image af the same empty sac. Note the ~nning af sac separation from the uterine wall (amlW).

miscarriage, especially if the patient is experiencing pain as well as bleeding? In 2014, the Society of Radiologists in Ultrasound published new criteria for identifying nonviable pregnancies and reducing the number of false-positive diagnoses of nonviable pregnancies in women who experienced vaginal bleeding or spotting in the first trimester. The resulting criteria and guidelines for follow-up sonograms were based on the findings of a total of 1,013 initial sonograms performed over a 10-yearperiod (from 1999 to 2008). Pregnancies of unknown location were excluded from the study. The authors found that the most reliable criteria for early nonviable pregnancies include the following: • An empty gestational sac (no visible embryo) with a mean sac diameter up to 25 mm (Fig. 16-2) • A crown-rump diameter of 7 mm for embryos without a detectable heartbeat1

SIZE-DATES DISCREPANCY If a patient is unsure of her last menstrual period (LMP), or if a clinical examination of the uterus does not agree with the patient's reponed LMP, her clinician may request a sonogram to date the pregnancy. The presence of uterine fibroids, maternal obesity, surgical scars, or multiple gestation may make it difficult for the obstetrician to estimate the size of the uterus, from which the gestational age is estimated. Because other aspects of pregnancy management (e.g., establi&hing the estimated date of delivery, methods of termination, interpretation of maternal serum levels, timing of chorionic villus sampling or amniocentesis) hinge on the correct assessment of the duration of pregnancy, the patient may be sent for ultrasound evaluation in the first trimester. When the uterus is smaller than expected, ultrasound is used to rule out incorrect dates, early pregnancy failure, or ectopic pregnancy. Once an intrauterine pregnancy is identified, careful measurements are taken to establish the gestational age. If the development of the gestational sac and its contents is less advanced than the patient's dates indicate, correlation with the hCG levels may be indicated, and serial sonograms may be performed to establish a normal rate of growth. Early-onset intrauterine growth restriction

{defined as a crown-rump length at least 2 standard deviations below the mean for the expected gestational age) in a woman with a reliable menstrual history is at increased risk for miscarriage (spontaneous abortion).8 A uterus that is large for gestational age may be due to incorrect dates, multiple gestation, molar pregnancy. or uterine fibroids. Contrary to earlier reports, most fibroids do not grow during pregnancy. However, fibroids may be associated with preterm labor, premature rupture of membranes, and fetal malposition. In the first trimester, retroplacental fibroids may be associated with vaginal bleeding, and large submucosal fibroids that distort the uterine cavity may be associated with pregnancy loss.9 Most pregnancies are clinically confirmed after a woman has missed a menstrual period and has had a positive urine or serum pregnancy test. An unknown number of pregnancies are spontaneously aborted before a woman has missed her menstrual period, without her or her obstetrician ever being aware of the pregnancy and its loss. As many as 10% to 20% of clinically recognized pregnancies result in spontaneous abortion before 20 weeks gestational age, with most of those occu.rri.ng before 12 weeks.~>-u Although pregnancy failure has many causes, 50% to 70% are caused by genetic abnormalities. 12 When an asymptomatic woman has an early sonogram (i.e., one performed between 6 weeks+ 2 days and 11 weeks + 6 days gestational age} that demonstrates a singleton pregnancy with a normal heart rate, the subsequent risk of miscarriage drops to 1.6%.2 In women with vaginal bleeding or pain, the risk of pregnancy loss increases. Approximately half of patients who experience vaginal bleeding miscarry, with the greatest risk seen in patients with heavy bleeding and pain. Of those patients whose pregnancies continue, 17% may experience complications later in pregnancy.31•12·u Other causes of vaginal bleeding in early pregnancy include gestational trophoblastic disease, which is covered later in this chapter, and ectopic pregnancy, which is reviewed in Chapter 17. The sonographic findings of early pregnancy failure depend on the stage of embryologic development at which they occur, and whether the uterus has begun to expel the products of conception.'

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PART TWO OBSTETRIC SONOGAAPHY

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B

FIGURE 16-3 Abnormal yolk sacs. A: Enlarted yolk sac. B: Collapsed, irTegular yolk sac. (Image A courtesy d Philips Healthcare, Bothell, WA)

In an anembryonic pregnancy (sometimes called a blighted ovum), the pregnancy either ended before a sonographically identifiable embryo formed, or the early embryo has been resorbed once the pregnancy failed. An empty gestational sac (i.e., a gestational sac devoid of embryo or yolk sac) with a mean sac diameter greater than 20 mm by transvaginal ultrasound is likely to indicate pregnancy failure/ A smaller-than-expected empty gestational sac in a patient with reliable dates may also predict a poor outcome. 14 Because there is some overlap between the measurements of viable and nonviable pregnancies, it may be prudent to do a follow-up examination in a desired pregnancy with a borderline sac measurement.7•9•14•15 The first structure to be sonographically identified in a normally developing gestational sac is the secondary yolk sac (secondary umbilical vesicle). Yolk sacs that are too large (greater than 2 standard deviations above the mean yolk sac diameter for a given gestational age), too small {more than 2 standard deviations below the mean yolk sac diameter for gestational age), or do not show the characteristic round appearance are strong predictors of a poor outcome (Fig. 16-3).16-18 In normal pregnancies, visualization of the amnion surroWlding the early embryo occurs after sonographic identification of the yolk sac. In 2010, Yegul and Filly reported that visualization of an amnion without sonographic evidence of an embryo (the "empty amnion sign"} is definitive evidence of pregnancy failure. 19 Cardiac activity in an embryo measuring S mm or greater is generally thought to be a reassuring sign, and the risk of spontaneous abortion is low. However, bradycardia {heart rate vessel umbilical coro.

B

A

FIGURE 20-19 Color Doppler of the umbilical cord. A: Sagittal ultrasound image showing color Doppler applied to a 1hree-vessel umbilical cord demonstraling two arteries and a si~ vein witn appropriate cortl coiling. B: Sagittal ultrasound image of a two-vessel umbilical cortl with a single umbilical artery.

A

B

FIGURE 20-30 TI'CU'6'/erse peMs ~ew. A: In tne trar6\lerse ~ew of1tte fetal pelvis, two umbilical arteries can be seen coursing around 1he fetal urinary bladder using power Doppler angiography. confirming the presence of a1hree-vessel umbilical cortl. B: In the same Vif!W, only one umbilical artery is identified adjacent to the fetal bladder; consislent with a twc>vessel umbilical cord. 8, bladdl!f:

20 ABNORMALITIES OF THE Pl..ACENTAAND UMBILICAL CORD

FIGURE .20-3 I Supernumerary vessels. A cross-seaional ultrasomd imaged an umbilical oon:l demoi'IStr.i!ing multiple ~li in a case of conjoined twiming.

sonographic evaluation, the umbilical vein curves toward the left-sided stomach rather than toward the liver (Fig. 20-32). In addition, the gallbladder is located medial to the vein rather than its normal lateral position. It is usually an isolated finding, but may have a risk of associated anomalies including cardiac malformations.9 An umbilical vein varix may be present and is described as a focal dilatation of the umbilical vein. Varix of the umbilical vein is usually seen in the intraabdominal, extrahepatic portion of the umbilical vein (Fig. 20-33). Color Doppler imaging permits the diagnosis of umbilical vein varix {Fig. 20-34). Diagnostic criteria include an abdominal vein diameter of greater than 9 m:m or an enlargement of the varix of at least 50% larger than the diameter of the intrahepatic umbilical vein. Although most cases have a normal outcome, some studies have shown an association with other anomalies, aneuploidy, perinatal death, and hydrops.9

Abnormalities of Stn1cture Body stalk anomaly (complete absence of the umbilical cord) and limb-body wall complex (a very short cord) are rare occurrences associated with severe structural anomalies.

A FIGURE 10-ll

Body stalk anomaly is a fatal condition that has been linked to maternal cocaine abuse. Sonographically, no cord would be identified, but rather an extraembryonic sac in direct apposition to the chorionic plate. Again, severe fetal malformations would be obvious on sonograpbic evaluation, the most common being scoliosis, abdominal wall defects, and neural tube defects (Fig. 20-35). The average length of the umbilical cord is 55 em in a normal term newborn. The length of the umbilical cord is considered an index of fetal activity and depends on the tension created by the freely mobile fetus primarily during the first and second trimesters. CUrrently, measurements of umbilical cord length are not widely applied in obstetrics. A short cord has been defined as 35 em or less and has been associated with fetal anomalies (often lethal) in which fetal movement is limited or absent, such as body stalk anomaly, limb-body wall complex, restrictive dermopathy, ichthyosis, Neu-Laxova syndrome, and fetal akinesia/hypokinesia {Pena-Shokeir syndrome) sequence. It is also considered a significant marker for developmental abnormalities, including trisomy 21. In addition, normal fetuses with short umbilical cords are reported to manifest an increased risk of adverse antenatal and intrapartum complications, including umbilical cord rupture, failure to descend, umbilical vessel hematomas, thrombosis, tluombocytopenia, cord compression, variable heart decelerations, instrumental and operative deliveries, and fetal demise. 38 An abnormally long umbilical cord may predispose to vascular occlusions by thrombi and true knots, stricture, nuchal cord, cord entanglement, and cord prolapse during labor.39

Abnormalities of Cord Insertion In recent years, the umbilical cord insertion into the placenta has gained more attention, and in 2013 was added as a component of the standard fetal examination at 16 to 20 weeks of gestation as decided by multiple organizations in an ultrasound fetal imaging workshop.14 TYPically, the umbilical cord inserts at or near the center of the placental disc in over 90% of cases (Fig. 20-36).4 The placental umbilical cord insertion site can be readily determined by

B Pe~istent right umbilic:al vein./4:: Transver.;e '\fie.N of the fetal abdomen. labeled right and left. showing the

umbilical vein cou~ilg to the fetal left.

B: Color Doppler image of the fetal abdomen demonslrate51he ~~nbilical vein cuf'\ling 1Dward the fetal stomach ra!her than 1he fetal liver. S, stomach; UV. urrbilic:al vein.

450

PART TWO OBSTETRIC SONOGAAPHY

A FIGURE 20-J:J Umbilical vein varix. A:. Transven-e section of the fetll abdomen showing focal dilalation c:i the fetal umbilical vein as it enters the fetal abdomen. B: Similar CASed umbilical vein varix where the intra-abdominal portion of the umbilical vein measures II mm (arrow). ST. stomad1; UV. umbilical vein.

A

B

FIGURE 20-.14 Umbilical vein varix. A: Color Doppler imaging !t!CMiing tllrbulent flaw in the cystic dilirtaiion of the umbilical vein as it enters the fetal abdomen (atrow). B: Spe 0.3 coilskm).

FIGURE 20-55 Noncoiled umbilical cords. A:. Sagittal color Doppler image d a noncoiled 1hree-vessel umbilical cord. B: ~ color Doppler image of

noncoiled two....essel umbilical cord.

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PART TWO OBSTETRIC SONOGAAPHY

FIGURE 20-56 Dual-screen ultrasound image showing power Doppler and 2D ima.l')ng d a hypefcoiled umbilical cord.

A

B

FIGURE 20-57 Cord ent3llllement. A: Gross pathology photograph of a monoamniotk twin placenta showing entanglement d the umbilical cords. Note tne ori~n d ead1 umbilicAl cord at the placental surface (an'DWS). B: Significant ent3rlglement of the twin umbilical cords is appreciatEd in this monoamniotic placenta. (Images courtesy d Pathology Associates d Syracuse, Crouse Hospital, Syracuse, NY.)

Long umbilical cord Narrow umbilical cord with diminished Wharton Jelly

Stricture Nuchal/body cords True knots of the umbilical cord Umbilical cord prolapse Hypercolled umbilical cord Abnormal umbilical cord Jnserdon Into the placenta • Velamentous cord Insertion • Vasa previa FIGURE 20-58 Cord stricture. Postnatal photognlpn of a fetus with umbilical cord stricture. Note the long, I'\CII'TOW umbilical cord (CIIroW).

• Succenturiate lobe

20 ABNORMALITIES OF THE Pl..ACENTAAND UMBILICAL CORD

SUMMARY

• The placenta increases in both volume and thickness as the gestation progresses. • The normal placental thickness is generally between 2 and4cm. • Abilobed placenta is a connected bridge of placental tissue. • A succenturiate lobe is a mass of placental tissue with a location distant from the main placenta. • Placental extension beyond the chorionic plate with attachment of the placental membranes to the fetal surface of the placenta describes both circumrnarginate and circumvallate placentas. • Implantation of the placenta within 2 em of the internal cervical os is considered a low-lying placenta. • The term MAP refers to an abnormal implantation of the placenta into the uterine wall. • A history of prior cesarean section increases the risk of placenta accreta development. • Anechoic structures inferior to the chorionic plate with real-time imaging of swirling jets are normal placental lakes. • Hypoechoic fibrin deposits are a normal finding in the placenta. • Small hypoechoic hemorrhagic areas within the placenta occur in half the pregnancies at midterm. • Massive subchorionic hematoma and thrombosis of the placenta is a rare occurrence called a Breus mole. • IUGR has an association with placental infarction. • Large chorioangiomas, vascular malformations of the placenta, have an association with serious fetal complications. • Placental and cord teratomas have a similar cellular makeup as seen with this type of tumor in other areas of the body. • Placental abruption has a limited diagnosis with ultrasound. • Amniotic band syndrome is the rupture of fetal membranes with potential entrapment of fetal parts. • Uterine synechiae are extra tissue outside the amniotic sac without fetal entrapment. • Placenta mesenchymal dysplasia mimics a molar pregnancy. • The average umbilical cord length is 55 ern {21.7 inches). • Wharton jelly covers the outside of the umbilical cord. • An umbilical cord with a SUA is associated with an increased incidence of chromosomal anomalies. • The presence of more than three umbilical cord vessels has a relationship to conjoined twins and singleton pregnancies with multiple anomalies.

A

• Umbilical vein curvature to the left side of the fetal abdomen indicates a possible persistent right umbilical vein. • An umbilical cord varix is a focal dilatation of the intraabdominal umbilical vein that measures greater than 9 mm. • The umbilical cord may be absent or extremely shortened in limb-body wall complex and body stalk anomaly. • Abnormal cord insertions into the placenta include marginal insertion, velamentous insertion. vasa previa. and furcated insertion. • Abnonnal cord insertions into the fetal abdomen are either due to an omphalocele or gastroschisis. • Cysts of the umbilical cord can be either true cysts or pseudocysts. • Color Doppler imaging is instrumental in demonstrating a nuchal cord. • Cord prolapse occurs at birth if the cord presents before the fetus. • Monochorlonic/monoamniotic twins have a significant risk for umbilical cord entanglement. • Umbilical cord torsion can result in stricture of the umbilical cord. CRITICAL THINKING QUESTIONS

1. A thick placenta images during a routine obstetric examination. Explain the significance of this finding. Describe the placental, maternal. and fetal conditions that coexist with a thick placenta. 2. A 36-year-old G4P2Al patient presents to the department with complaints of bright spotting. This nonsmoking patient had a lower segment emergency cesarean section with her second pregnancy and dilation and curettage with her miscarriage. What is the most likely differential for the finding on this longitudinal low image? What further steps would confirm the diagnosis? MEDIA MENU

Student Resources available on • Audio glossary • Interactive question bank • Videos • Internet resources

B

Poinf include:

464

PART TWO OBSTETRIC SONOGRAPHY

REFERENCES L Elsayes KM, 'Itout AT, Friedkin AM, et al. Imaging of the placenta: a multimodality pictorial review. Radiographies. 2009;29:1371-1391. 2. Abramowicz JS, 8heiner E. In utero imaging of the placenta: importance for diseases of pregnancy. Placenta Suppl. 2007;21 :814-822. 3. Sabire NJ, Sepulveda W. Correlation of placental pathology with prenatal ultrasound findings. J Clin Patlwl. 2008;61:1276-1284. 4. Marino T. Ultrasound abnormalities of the amniotic fluid, membranes, umbilical cord, and placenta. Obstet Gynecol Clin North Am. 2004;31:177-200. 5. Suzuki S, Igarashi M. Clinical significance of pregnancies with succenturiat e lobes of the placenta. Aldl Gynecol Obstet. 2.008;277:299-301. 6. Ahmed A, Gilbert-Barness E. Placenta membranace a: a developmental anomaly with diverse clinical presentation . Ped.iD.tr Dev Pathol. 2003;6:201-203. 7. Greenberg JA, Sorem KA, Shifren JL, et al. Placenta membranace a with placenta accreta: a case report and literature review. Obstet Gynecol. 1991;78:512-514. 8. Feldstein VA, Harris RD, Machin, GA. Ultrasound evaluation of the placenta and umbilical cord. In: Callen PW, ed. mtrasonogra phy in Obstetrics and Gynecology. 5th ed. Philadelphia: Saunders Elsevier; 2008:721-757. 9. Sepulveda w, Sohaey R, Nyberg DA. The placenta, umbilical cord, and membranes. In: Nyberg DA, McGahan JP, Pretorius DH, et al., eds. Diagnostic Imaging ofFetal Anonuzlies. Philadelphia: Uppincott Williams & Wilkins; 2003:85-132. 10. Harris RD, Wells, WA, Black we, et al. Accuracy of prenatal sonography for detecting circumvallate placenta. Am J Roentgenol. . 1996;168:1603-1608. 11. Suzuki s. Clinical significance of pregnancies with circumvallate placenta. J Obstet Gynecol Res. 2008;34:51-54. 12. Shen 0, Golomb E, Lavie 0, et al. Placental shelf-a common, typically transient and benign finding on early second-trime ster sonography. mtrasound Obstet Gynecol. 2007;29:192-194. . 13. Gugmundsson S, Dubiel M, Sladkevi.cius P. Placental morphologic and functional imaging in high-risk pregnancies. Semin Perinatal. 2009;33:270- 280. 14. Reddy Urn, Abuhamad AZ, Levine D, et al. Fetal Imaging: Executive Summary of a Joint Eu.nic.e Kennedy Shri.uer National Institute of Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society of Pediatric Radiology, and Society of Radiologists in Ultrasound In Fetal Imaging Workshop. l mtrasound Med. 2014;33:745- 775. 15. Oyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Obstet Gynecol. 2006;107:927- 941. 16. Abuhamad A. Morbidly Adherent Placenta. Senim PeriTilltol. 2013:359-36 4. 17. Ophir E, Singer-Jorda n J, Odeh M, et al. Abnormal placental invasion-a novel approach to treatment. Obstet Gynecol Surv. 2009;64:811-822. 18. Bauer 8T, Bonanno C. Abnormal placentation . Semin Perinatal. 2009;33:88- 96. 19. Baughman we, Corteville JE, Shah RR. Placenta accreta: spectrum of US and MR imaging findings. Rndiogmphics. 2008;28:1905-1916. 20. Tho TH, Law YM, Tay KH, et al. Use of magnetic resonance imaging in evaluation of placental invasion. CUn Radial. 2009;64:511-516. 21. Thompson MO, Vines SK, Aquilina J, et al. Are placental lakes of any clinical significance? Placenta. 2002;23(8- 9):685-690. 22. Cerekja A, 'Ibzzi c, Piazze J. Available at: www.TheFetus.Net, Subamniotic Cyst 2011-05-25-15. 23. Taori K, Patil P, Attarde V, et al. Chorioangioma of placenta: sanagraphic features. J Qin Ultrasound. 2008;36:113-115. 24. Kirkpatrick AD, Podberesky DJ, Gray AE, et al. Placental chorioangioma. Radiographies. 2007;27:1187- 1190. 25. Kondi-Pafiti A, Bakalianou K, Salakos N, et al. Placental chorioangioma and chorioangiosis. Clinicopathological study of six unusual vascular lesions of the placenta-ca se reports. Clin F.JqJ Obstet Gynecol. 2009;36:268- 270. 26. Escribano D, Galindo A, Arbu~s J, et at. Prenatal managemen t of placental chorioangioma: value of the middle cerebral artery peak systolic velocity. FetalDiagn Ther. 2005;21:489-493.

27. Salzani A, Yela DA, Gabiatti JR, et al. Prevalence of uterine synechia after abortion evacuation curettage. SaD PrWlo Med J. 2007;125:261-264. 28. Baumler M, Faure J-M, Couture A, et al. Prenatal 3D ultrasound and MRI assessment of horizontal uterine synechia. Prenat Diagn. 2008;28:874-875. 29. Parveen z, 'Ibngson-Ignacio J, Fraser CR. et at. Placental mesenchymal dysplasia. Aldl Patlwl Lab Med. 2007;131: 131- 137. 30. Ang DC, Rodriguez Urrego PA, Prasad V. Placental mesenchyma l dysplasia: a potential misdiagnosed entity. Aldl Gnyecol Obstet. 2009;279:937-939. 31. Jalil SS, Mahran MA, Sule M. Placental mesenchym al dysplasia-can it be predicted prenatally? A case report. Prenat Diagn. 2009;29:713-714. 32. Vaisbuch E, Romero R, Kusanovic JP, et al. Three-dimen sional sonography of placental mesenchyma l dysplasia and its differential diagnosis. J Ultrasound Med. 2009;28:359 -368. 33. Sepulveda W, Wong AE, Gomex L, et al. Improving sonographic evaluation of the umbilical cord at the second-trimester anatomy scan. J Ultrasound Med. 2009;28:831-835. 34. Dane B, Dane C, Kiray M, et al. Fetuses with single umbilical artery: analysis of 45 cases. Clin Exp Obstet Gynecol. 2009;36:116-119. 35. de Laat MW. Franx A. van Alderen ED. et al. The umbilical coiling index, a review of the literature. J Matern Fetal Neonatal Med. 2005;17:93-100. 36. Mu SC, Lin CH, Chen YL, et al. The perinatal outcomes of asymptomatic isolated single umbilical artery in full-term neonates. Ped.iD.tr Neonatal. 2008;49:230-233. 37. Deshpande SA, Jog S, Watson H, et al. Do babies with isolated single umbilical artery need routine postnatal renal sonography? Alrh Dis Otild Fetal Neonatal Med. 2009;94:F265-F267. 38. Sherer DM, Dalloul M, Ajayi 0, et al. Prenatal sonographic diagnosis of short umbilical cord in a dichorionic twin with normal fetal anatomy. J Clin Ultrasound. 2010;38:91-93. 39. Graham DG, Fleischer AC, Sacks GA. Sonography of the umbilical cord and intrauterine membranes. In: Fleischer AC, Romero R, Manning FA, et al., eds. 111£ Principles and Practice ofUitrasonogc raphy in Obstetrics and Gynecology. 4th ed. Norwalk: Appleton & Lange; 1991:159-170. 40. Sepulveda W Velamentous insertion of the umbilical cord-a first trimester sonographic screening study. J Ultrasound Med. 2006;25:963-968. 41. Hasegawa J, Matsuoka R, Ichizuka K, et al. Cord insertion into the lower third of the uterus in the first trimester is associated with placental and umbilical cord abnormalitie s. Ultrasound Obstet Gynecol. 2006;28:183-186. 42. Hasegawa J, Matsuoka R, Ichizuka K, et al. Umbilical cord in~­ tion into the lower uterine segment is a risk factor for vasa prev1a. Fetal Diagn Ther. 2007;22:358-360. 43. Hasegawa J , Matsuoka R, Ichizuka K, et al. Velamentous cord insertion: significance of prenatal detection to predict Perinatal complications. Taiwan J Obstet Gynecol. 2006;45:21-25. 44. Hasegawa J, Matsuoka R, Ichizuka K, ~t al. Atypic~ v:mable deceleration in the first stage of labor ts a charactensti c fetal heart-rate pattern for velamentous cord insertion and hypocoiled cords. J Obstet Gynerol Res. 2009;35:35-39. 45. Hasegawa J, Matsuoka R, Ichizuka K, et al. Ultrasound diagnosis and managemen t of umbilical cord abnormalities. Taiwan J Obstet Gynecol. 2009;48:23-2 7. 46. Canterino JC, Mondestin-Sorrentino M, Muench MV, et al. Vasa previa: prenatal diagnosis and evaluation with 3-dimensiona l sonography and power angiography. J Ultrasound Med. 2005;24:721-7~. 47. Catanzarite v, Maida C, Thomas W, et al. Prenatal sonographic diagnosis of vasa previa: ultrasound findings and obstetric outcomes in ten cases. mtrasound Obstet Gynecol. 2001;18:109-115. 48. Smorgick N, Tovbin Y, Ushakov F, et al. Is neonatal risk from vasa previa preventable? The 20-year experience form a single medical center. J Clin Ultrasound. 2010;38:118-122. 49. Stafford IP, Neumann DE, Jarrell H. Abnormal placental structure and vasa previa: confirmation of the relationship. J Ultrasound Med. 2004;23:1521-1522. so. Gandhi M, Cleary-Goldman J, Ferrara L, et al. The association between vasa previa, multiple gestations, and assisted reproductive technology. Am J Perinatal. 2008;25:587-590.

lO ABNORMALITIES OF THE PLACENTA AND UMBILICAL CORD

51. Lijoi AF, Brady J. Vasa previa diagnosis and management. JAm Board Fam Pract. 2003;16:543-548. 52. Gagnon R, Morin L, Bly S, et al. Guidelines for the management of vasa previa. J Obstet Gyru:zecol Can. 2009;31:748-760. 53. Araujo E Jr, Filho HA, Pires CR, et al. Prenatal diagnosis of vasa previa through color Doppler and three-dimensional power Doppler ultrasonography. A case report. Clin Exp Obstet Gynecol. 2006;33 :122-124. 54. Lee w, Kirk JS, Comstock CH, et al. Vasa previa: prenatal detection by three-dimensional ultrasonography. Ultrasound Obstet Gynecol. 2000;16:384-387. 55. Oyelese Y, Catanzarite v, Prefurno F, et al. Vasa previa: the impact of prenatal diagnosis on outcomes. Obstet Gynecol. 2004;103:937-942. 56. Reddy UM, Goldenberg R, Silver R, et al. Stillbirth classification-developing an international consensus for research. Obstet Gynecol. 2009;114:901-914. 57. Sherer DM, Anyaegbunam A. Prenatal ultrasonographic morphologic assessment of the umbilical cord: a review. Part I. Obstet Gynecol Surv. 1997;52:506-514. 58. Weichert J, Chiriac A, Kaiser M, et al. Prenatal management of an allantoic cyst with patent urachus. Arch Gynecol Obstet. 2009;280:321-323. 59. Iyoob SD, Tsai A, Ruchelli ED, et al. Large umbilical cord hemangioma: sonographic features with surgical pathologic correlation. J Ultrasound Med. 2006;25:1495-1498.

465

60. Papadopoulos VG, Kourea HP, Adonakis GL, et al. A case of umbilical cord hemangioma: Doppler studies and review of the literature. Eur J Obstet Gynecol Reprod Biol. 2009;144:8-14. 61. Sherer DM, Anyaegbunam, A. Prenatal ultrasonographic morphologic assessment of the umbilical cord: a review: part II. Obstet Gynecol Suro. 1997;52:515-523. 62. Tantbirojn P, Saleemuddin A, Sirois K, et al. Gross abnormalities of the umbilical cord: related histology and clinical significance. Placenta. 2009;30:1083-1088. 63. Ram6n y Cajal CL, Martinez RO. Four-dimensional ultrasonography of a true knot of the umbilical cord. Am J Obstet Gyneool. 2006;195:896-898. 64. Hasbun J, Alcalde JL, Sepulveda W. Three-dimensional power Doppler sonography in the prenatal diagnosis of a true knot of the umbilical cord. J UltrasoundMed. 2007;26:1215-1220. 65. Strong TH, Jarles DL, Vega JS, et al. The umbilical coiling index. Am J Obstet Gynecol. 1994;170:29-32. 66. Sebire NJ. Pathophysiological significance of abnormal umbilical cord coiling index. Ultrasound Obstet Gynecol. 2007;30:804-806. 67. Machin GA, AckermanJ, Gilbert-Barness E. Abnormal cord coiling is associated with adverse perinatal outcomes. Pediatr Dev Pathol. 2000;3:462-471. 68. Henrich W, 1\ltschek B. Cord entanglement in monoamniotic twins: 2D and 3D colour Doppler studies. Ultraschall in Med. 2008;29:271-272.

Sonographic Assessment of the Fetal Head JULIA DMITRIEVA

OBJECTIVES

KEY TERMS

• Explain embryonic development of the face and brain

microcephaly

• List the normal anatomic landmarks for biometry of the cerebellum. ventricles. orbits, and cisterna magna

hypotelorlsm

hypertelorilm

• Identify the meroanencephalic fetus

microphthalmia

• Differentiate the Amold-Chiari malformation from the Dandy-Walker malformation

macroglossia

• Discuss sonographic approach to obtaining the images of the fetal face

micrognathia

• Conduct an overview of facial abnonnalities

cleft lip

• Classify cleft lip and palate defects

cleft: palate

• Discuss embryology of the eye and leading orbital and periorbital anomalies

meroanencephaly

• Relate sonographic features to discussed face and brain anomalies

hydranencephaly

GLOSSARY Anophthalmia Congenital absence of one or both eyes Brachycephaly Short broad head due to prernab.Jre suture fusion Cebocephaly Congenital anomalies of the head due to teratogens or development disruptions of the nervous system Colpocephaly Congenital brain anomaly resulting from a migrational defect of the occipital homs of the lateral ventricles leading to ventricular enlargement Dysgenesis Abnormally fonned organs Dysmorphic. Malfonnation of an organ or structure Dolichocephaly Long narrow head Ectasia Dilatation or distention of a hollow structure Nares Nostrils Neuropore Either the rostral or caudal end of the neural tube

Nomogram Graph Padtognomonic Disease characteristic Retrosnathia Posterior displacement ofthe maxilla and mandible Rostral Toward the cephalic or head end Teratogen Substance that interferes with embryonic development Vermis Central portion of the cerebellum between the hemispheres

holoprosencephaly

apnesis of the corpus callosum Dandy-Walker malformation schizencephaly lissencephaly cephalocele

iniencephaly Arnold·Chiari malformation

ventrlculomegaly hydrocephalus choroid plexus cysts porencephaly

intracranial hemorrh:age aneurysm of the vein of Galen

-467

PART TWO OBSTETRIC SONOGAAPHY

E

valuation of the fetal head is an important part of an obstetric ultrasound examination. The American College of Radiology, the American Institute of l.fltrasound in Medicine, the American College of Obstetricians and Gynecologists, and the Society of Radiologists in l.fltrasound regularly update the guidelines describing the clinical aspects of fetal ultrasound examinations. First-trimester ultrasound examination includes evaluation of the embryonic/fetal anatomy and nuchal region. Second- and third-trimester examinations include assessment of fetal biometry and anatomic survey. According to guidelines, minimal elements of the fetal anatomic examination include lateral cerebral ventricles, choroid plexus, midline falx, cavum septi pellucidi, cerebellum, cisterna magna, and upper lip. 1 Each section in this chapter begins with an explanation of the normal embryogenesis of the brain, and face and a basic protocol for examining the fetal brain and fetal face, pausing at various points to provide a detailed description of observed anatomy. In the second part of this review, a discussion of various abnormalities of the fetal head allow for recognition of anomalies.

EMBRYOLOGY OF THE BRAIN Neural plate development completes at approximately daysl8 to 23.2.3 During the endovaginal examination, a hypoechoic region within the echogenic decidua identifies the coelomic cavity of the gestational sac. At approximately six menstrual weeks, the neural tube differentiates into the primitive brain and spinal cord. Three segments make up the brain: the prosencephalon {forebrain), the mesencephalon (midbrain), and the rhombencephalon (hindbrain) (Fig. 21-1). Identification of these primary vesicles occurs at approximately 7 to 8 weeks, with the rhombencephalon im:rng as an anechoic structure in the fetal head {Fig. 21-2).4 The forebrain becomes the telencephalon and diencephalon, resulting in the development of the thalami, third ventricle, cerebral hemispheres, and the lateral ventricles. Invagination of the choroid plexus into the ventricles results in abnost complete filling of the anechoic ventricles with the hyperechoic plexus (Fig. 21-3).2•4 As the brain develops,

FIGURE 11-1 The crescent-shaped sonolucency in 1he anterior aspect d 1he brain is crecrted by 1he diencephalon and 1he mesencephalon. Qmage courtesy ol' Philips Healthc3re, Bethell, WA)

the choroid plexus takes its position in the posterior area of the lateral ventricles. The metencephalon and myelencephalon arise from the anechoic rhombencephalon. The upper portion of the fourth ventricle, pons, and cerebellum originate from the metencephalon, whereas the medulla and rest of the fourth ventricle originate from the myelencephalon. Anatomy such as the corpus callosum, cerebellar vermis, sulci, and gyri, and migration of the germinal matrix and myelination develop after 15 weeks' gestation.6 Even later, at about 18 to 20 weeks, development of the corpus callosum completes.6 This includes the boxlike cavum septum pellucidum (CSP). Brain sulci and gyri image by 28 weeks; however, some of the larger sulci may image earlier.6 Many structures develop between week 3 and 16, resulting in this time frame being identified as the critical period of brain development.3 The rapid growth of the brain throughout

Ro.s1ral Prosencephalon or forebrain Mesencephalon or midbrain

Rhombencephalon or hindbrain Caudal FIGURE 21-1 The three primarybrain~icles. The rostral end of the neural tube differentiates to form the 1hree vesides that five rise to 1he entire brain. This view is from above, and 1he vesicles have been cut horizontally so that we can see the inside af the neural tlJbe.

FIGURE 11-3 The lateral ventrides, largely filled with choroid plexus, appear to occupy most of1he hemispheres of the developing brain. Omage courtesy af Pnilips Healthcare. Bothell, WA)

21

gestation and the first 2 years of life allows for teratogens or nutritional deficits to influence the brain.3 The causes of congenital anomalies are not well understood, though an association with several environmental factors has been found. These include lack of folic acid {shown to correlate with an increase in central nervous system anomalies) 5 and exposure to 1bxoplasma gondii and high levels of radiation (Table 21-1}.3 TABLE 21-1

SONOGRAPHIC ASSESSMENT OF THE FETAL HEAD

ANATOMIC LANDMARKS AND BIOMETRY Axial Views of the Head Biparietal Diameter Level The fetal biparietal diameter (BPD) was the first sonograpbic measurement used to determine gestational age. 7•8 Initially

Embryoni~ Development Chart for the Brain,

DaJs PancnulllltiDIV

CUneaieStace

Und"drerentillted Neund Development

and Face1-J

Brain

Face

EmbrJDSize

FIRST TRIMESTER 16 da.ys/7

Neural crest cells organize in the neural rube

0.04an

18days/d

Ectodenn has become the neural plate, which develops the neural groove

0.1~.15an

Cells that become e)leS and ears appear lateral to the neural folds

0.15~.3

stage 9 continues

24days/ll

Forebrain oompletely dosed

Stomodeum develops

0.25~.3an

26days/12 Brain and spine combined fonn the la~st portion of the embryo

Forebrain ccnt:inues growing

Facial arches appear; eye and ear begin to fonn

0.3-0.San

32days/14 Gestational sac seen with ultrasound

Ridges develop separating the midbrain, forebrain, and hindbrain

Mandibular arches and nasal plate develop

0.5--0.7mm

36 days! I5

Brain increases in size by I/3 from stage 14, fourth ventricle fonns

Mandibular prominence fuses,

0.7-0.9mm

22days/IO

38days/16

Brain foldi~ beginning in

Cerebral hemispheres and hindbrain begin to develop

an

external ears and nasal pits begin to appear

Mandible demarcates, nasal pits rolllte ventrally, median palatine process appears

0.9-1.1 an

43 days/17 Embryo with heart belrt images with ultrasound

Teeth buds fonn, palatine processes in a horizontal position

1.0-1.3 an

52days{ll

Eyes developed but still

1.7-2.2an

on lateral head, ears low set, tongue development completes 57 days{13 Imaging of neural tube possible with ultrasound

Pala:te and nasal septum begin fusion, ear fonned

2.3-2.6an

SECOND TRIMESTER IOweeks

Fonnation complete, brain size increases 1l::> 6.1 em

Eyelids fused, intennaxillary segment continues fusion

3.1-4.2an

12th week

Head about half aown-rump length

Palate fusion completes

6.1 an

14th week

Philtrum of lip forms

16weeks

Eyes and ears move to final

location 28weeks

Gyrus and suld begin forming

470

PART TWO OBSTETRIC SONOGAAPHY

defined as the widest distance between the parietal eminences,

bilaterally. Third, position the cursors on the outer edge of the proximal skull to the inner edge of the distal skull.1•2 The BPD maintains its closest correlation with gestational age in the first and early second trimesters. However, this accuracy is lost in the third trimester because of variations in the shape of the fetal skull. As the pregnancy progresses and the head conforms to the pelvis, the result is either a dolichocephalic or brachycephalic head shape.2 The head circumference (HC) or head perimeter is shape independent and can be used as an alternative mea.surement1 {Fig. 21·4A,C).

the BPD measurement levels are consistent between medical facilities. BPD is measured at the level of the thalami and cavum septi pellucidi or columns of the fornix. Cerebellum should not be visible in this plane (Fig. 21-48).1 Other structures commonly observed in the same plane and near the midline are the following from posterior to anterior: the great cerebral vein, or vein of Galen, and its ambient cistern sitting above the cerebellum.4 the midbrain, the third ventricle between the thalami, and the frontal horns of the lateral ventricles. Laterally placed in the same plane are the spiral hippocampal gyri5 posteriorly and the bright paired echoes of the insulae with pulsating middle cerebral arteries. To obtain a properly measured BPD, orient the transducer in two planes: perpendicular to the parietal bones and positioned at the correct cephalocaudal position to intersect the third ventricle and thalami. Callenz describes three sonographic rules for obtaining the BPD. The first two criteria define the precise plane of section, and the third describes the proper endpoints of measurement. First, the correct plane of section is through the third ventricle and thalami. Second, the calvaria are smooth and symmetric

Mic:roc:ephaJy/Mic:roenc:ephaJy The literal meaning of microcephaly is ·small head... Its diagnosis, therefore, is based on biometry rather than on morphology. Consequently, diagnosis requires accurate dating. Although different biometric standards have been described to define microcephaly, a reliable indicator is a head perimeter two to three standard deviations or more below the mean for gestational age..z.6 Identifying fetal microcephaly can be challenging. Since head measurements alone may be hampered by incorrect dating or intrauterine growth restriction, alternative

A

B

FIGURE 21-4 A: The bractlycephalic fetll head has a shortened oa:ipital-fronml distance and a larger BPD. The slittike thi~ ventricle (~ images between the anterior portion of the two thalami. B: The normal-shaped head demonstrati!'i the hypoedloic: thalamus (stats). This is the main indicator for the BPD and HC ~rement level. C: The long narrow head, dolichocephaly, would result in a smaller1han gestational age BPD measurement and a lengd1eneNer: 2010: F.gure 31-12.)

19 MULTIPLE GESTAllONS

681

FIGURE 29-16 Vanishing twin. A: M. 8 weeks. 1tlere are two fetuses (orn7NS), eadl in its own gestational sac. Heartbeats were seen in both. B: M. 12 weeks, one of the fetl.lses (OO'OW) was small and had no heartbeat. while the other (cdipers) had grown normally and demonstrated canliac: activity. C: P¢. 16 weeks, the scan showed a singleton pregnancy with no evidence of the prior twin. (!Tom Doubilet PM, Benson CB. Atlas of Ult:rasound in Obstetrics CXld ~· 2nd ed. Philadelphia: Wolters Kluwer; 20 II: Rgure 20. 1-5.)

imaged twins. This rate of spontaneous demise is actually similar to that of spontaneous singleton demise. Early fetal demise has not been associated with adverse outcome in the surviving twin. A study by Benson and colleagues looked at first-trimester twin pregnancies to determine criteria for predicting pregnancy outcome with regard to number of liveborn infants.45 Of 137 patients evaluated, 110 (80.3%) had viable twins, 12 (8.8%) had 1 infant, and 15 (10.9%) had none. The criteria they found to be statistically significant included gestational age at the time of the ultrasound (the inference being that the earlier the gestation, the more time in which demise might occur), chorionicity of the pregnancy, and abnormal sonographic findings, such as subchorionic fluid, uterine fibroid&, or discrepancy between sac sizes. Neither advanced maternal age nor ART appeared to have an effect on outcome. If fetal loss occurs in the second or third trimester, or in the setting of a MZ twin gestation, the demised fetus may develop into a fetus papyraceus.46 Instead of the usual complete decomposition and absorption of the fetus, the fetus papyraceus (paperlike) is preserved in a distoned form (Fig. 29-17). In twins, a postulated cause of fetus papyraceus is transient polyhydramnios of one fetus in a monochorionicdiamniotic pregnancy exerting a lethal compressive effect on the other twin. Fetal papyraceus occurs in 1 of 12,000 live binhs, but is more common in the subgroup of twin gestations (1 in 184 twin births)Y·

TECHNICAL PITFALLS Technical pitfalls exist in imaging multiple gestations. An important factor that should be borne in mind when determining whether there is a multiple-gestation pregnancy is that crescentic areas of implantation hemorrhage or amniotic-chorionic separation may be mista.ken for second gestational sacs or nonviable pregnancies (Fig. 29-18). The distinction is usually obvious by the configuration of the fluid collections and the lack of a well-defined decidual rind in nongestational collections. Although it seems intuitively unlikely, late in pregnancy a second fetus may be completely overlooked because the nondependent fetus obscures the underlying one. This possibility should be considered if the visualized fetus is situated more anteriorly than would be expected and if there are more fetal parts in the image than seem appropriate. Later in pregnancy, owing to relative decreases in amniotic fluid with respect to the fetal volume, imponant areas of fetal anatomy may be hidden, and an effon must be made to evaluate obscured anatomy by scanning from multiple angles and with the mother in different positions.

HIGHER-ORDER MULTIPLE GESTATIONS Although the average incidence of twins is 1 in 100 pregnancies, triplets occur in only approximately 1 in 7,600

PART TWO OBSTETRIC SONOGAAPHY

682

A

B FIGURE 29-17 A: Twin pregnancy with a normal tv.in in ltle amniotic sac: (on ltle lett) and a fetal demise, whicn resulted in a fetus papyraceus (on the rip}lr.). 8; Fetus papyraceus. One twin is laJger. and ltle 01her has been compressed and mummified, hence the term papyraceus. (Reprinted wiUl pennission fi'om Stevenson RE, Hall JG, Goodman RM, eds. Human Mal(rJrmatjons and Related Anomalies. New Yoric Oldbn::l Univer.;ity Press. 1993.)

pregnancies, and the spontaneous rates for quadruplet and quintuplet pregnancies are 1 in 729,000 and 1 in 65,610,000, respectively. 11 Interestingly, triplet pregnancies-and even quadruplet pregnancies-may be MZ. For example, 60% of triplet pregnancies are secondary to the fertilization of two ova, 30% arise from the fertilization of three ova, and 10% arise from the fertilization of a single ovum {Fig. 29-19).47

Multiple gestations are at significantly increased risk of adverse fetal and maternal outcomes.s.s,ts,41l It is for this reason that all multiple gestations should be considered high-risk pregnancies and periodic monitoring by sonography is warranted.

FIGURE 29-18 Rrst-trimester ultrasound shcming what appears to be three gestational sacs. However; sac: C was actually an early subd1orionic: bleed.

FIGURE 29-19 A triplet pregnancy demonstrating the placental twin peak sign (P) and the T sign (T). One abdomen (I) and two fetal heads (2, 3) confirm the triplet pregnancy. (Image c:omplimtmts of Philips Healttlc3re, Bothell, WA.).

COMPLICATIONS OF MULTIPLE-GESTATION PREGNANCIES

19 MULTIPLE GESTAllONS

683

FIGURE 29·20 Endovaginal ulltasound utilizing color Doppler to snow fetal vessels caveringthe internal cervical os (C11'1'0'fhad) consistent with avasa previa.

MATERNAL COMPLICATIONS Maternal complications include an increased mortality rate during pregnancy, delivery, and immediately postpartum that is three times higher than for a singleton pregnancy.s,s This is usually the result of hypertension or postpartum hemorrhage. Maternal admission to an intensive care unit is also twice as high in these patients.49 Except for an increased rate of cesarean section in advanced maternal age (AMA) twin pregnancies, age does not appear to be associated with an increased risk of adverse outcome.50

FETAL COMPLICATIONS The primary risk factors for mortality and long-term morbidity in the fetus of a multiple gestation are premature delivery and low birth weight.8,51 Fetuses from multiple gestations are 6 times more likely to be preterm and 13 times more likely to be born before 32 weeks than singleton pregnancies.5 This increased rate of preterm. deliveries contributes to the lower birth weights among fetuses of multiple gestations. Other risk factors in multiples are usually related to the type of chorionicity/amnionicity present. MZ twins are associated with an increased risk of congenital anomalies. 15•18.22 Monochorionic twins, sharing a placenta, run the risk of abnormal anastomoses of arteries and veins developing. This puts them at risk for TITS and TRAP sequence, as well as all of the sequalae associated with those processes.

VASA PREVIA Vasa previa is defined as fetal vessels overlying the cervical os due to insertion of the umbilical cord into the amniotic membrane rather than the placenta.3·sz It is a rare abnormality that is associated with fetal mortality due to rapid fetal exsanguination at the time of membrane rupture. The occurrence rate in singleton pregnancies is reported as 1/2,500 pregnancies.9 In a multiple pregnancy, this rate rises to 2.5%.8 ART has also been shown to increase the rate of vasa previa. Since many multiple gestations are often the result of ART, the higher rate observed in multiple gestations makes sense. Vigilant sonographic evaluation of the lower uterine segment, particularly in the setting of a low-lying

FIGURE 29-21 Vasa pre'llia on transabdominal scan. Sagittal image af lower uterine segment with color and spectral Doppler showing blood flow in vessels betweefl the fetal head (H) and cefVix (Cx). The spedral Doppler demonstrates an umbilical ar~ery wavefurm, proving these are umbilical vessels d a vasa previa. (From Doubilet PM, Benson CB. Atlas o(Uitrosound in Obstetrics end Oplecology. 2nd ed. Pniladelphia: 'Nolters Kluwer. 2011: Figure 19.2-3.)

placenta or a placenta previa, is therefore warranted when assessing a multiple gestation (Fig. 29-20). 1\'ansvaginal ultrasound with color Doppler should be used to facilitate diagnosis as well as 3D multiplanar imaging (Figs. 29-21 and 29-22). The prenatal diagnosis of vasa previa increases survival rate to 97%.52

TWIN REVERSED ARTERIAL PERFUSION SEQUENCE TRAP sequence is also commonly referred to as acardiac twinning. It is a rare complication of monochorionic pregnancies, with a reported occurrence rate of 1/35,000 pregnancies and 0.3% of all MZ twin gestations.54 Diagnosing this abnormality occurs with observation of one normal twin, often referred to as the "pump" twin, and one amorphous twin without a well-defined cardiac structure, referred to as the "'acardiac" twin (Fig. 29-23). The acardiac twin is hemodynamically dependent on the normal twin for all circulation. In this abnormality, arterial-to-arterial and venous-to-venous anastamoses occur on the surface of the shared placenta. This results in blood flowing from the pump twin to the placenta via its umbilical arteries, then entering the abnormal arterial-to-arterial connections and flowing in a retrograde fashion to the acardiac twin through the umbilical arteries. Since this blood flow has essentially not gone through the placenta, it is relatively deoxygenated and nutrient poor. The blood enters the acardiac twin via the hypogastric arteries and essentially perfuses only the caudal aspect of the fetus. This is why usually only the lower pelvis and extremities of the acardiac twin tend to develop. More cephalic structures, such as the head, upper body, and heart are either completely absent or severely maldeveloped.u The blood returning from the acardiac twin flows back to the placenta via the umbilical vein. Color and/or spectral

PART TWO OBSTETRIC SONOGAAPHY

FIGURE 29-12 Multiplanar tran!M!ginal 3D sonogram d the vasa previa at 34 weeks gestation. A: Sagittal view showing a vessel running in a~ direction OYer the internal os. The arrow points to the internal os. 8; Coronal view showil"l: a cross section d the vessel ji.St behind the internal os. The arrow points to the internal os. C: Transverse view with the reference dot at the internal os showi~ the vessel crossing the c:eMx just at the le\9";. r.t•p HPRF :&&67Hz

FIGURE 29-31 Thickened interventricular septum and heart walls af the right (RY) and left {LV) ventrides, consistent wilh concenltic hypertrophy in the recipient twin of a TTTS pregnancy. LA, left atrium, RA.. rW1t atrium.

Formlltion

Monoc:horionir/diamniotic twins

Arterial and -venous anastD·

-tO

·' R

.)

R

., ,. R

.

..:. R

moses between placentas m/s

- -10

R

R

- -20

- -3.0

E!lm -

-40

FIGURE 29..30 Spedral wavefOrm showing mCLSSive tricuspid n::gurgitation (R) in tne recipient twin of a TTTS pregnancy. LA. left alrium; Lll, left ventricle; RA, right atrium; R\f, ~t ventride.

Flow shunting from one fetus to 1he other creating a perfusion Imbalance

Redpient twin • Polyhydramnios • Macrosomic • Hypervolemic

• Plethoric • Hydrops Donor twin

• Oligohydramnios • Growth restricted • Hypcwolemic • Anemic Same gender 2096 weight discordance Cardiovascular

are usually right-sided defects including pulmonary stenosis or atresia, resulting from the hypertrophied ventricular heart walls and interventricular septum obstructing right ventricular outflow (Fig. 29-31). The hypovolemic donor twin is at significantly less risk of developing cardiac pathology; however, dilated cardiomyopathies and small pericardia] effusions have been reported.63•67 For these reasons, formal fetal echocardiography is warranted in the setting of TITS. Velamentous cord insertion, in which the cord inserts directly into the membranes instead of the placenta, has been associated with a greater than 50% risk of TT'TS (Fig. 29-32).68 TITS can present at any time in pregnancy, but usually presents in the second trimester; therefore, serial screening ultrasounds should be performed on all monochorionic/ diamniotic twins. The ultrasounds should be done every 2 weeks after 16 weeks gestationP The earlier the onset, the poorer the prognosis.68 If left untreated, TITS has a reported mortality rate for both twins of 60% to 100%.68

malformations Velamentous cord insertion

Additionally, if one twin dies in utero, the surviving twin is at risk of developing multiorgan damage, specifically abnormalities of the brain, secondary to emboli from the deceased fetus. Adverse long-term neurologic deficits have also been reported in surviving infants.69•10 The prenatal sonographic diagnosis of 1TIS relies on identification of a single placenta, same sex fetuses, a weight discordance of greater than 2096 between the fetuses, and signifi.ca.nt discrepancy in amniotic fluid volume. A "stuck" twin is usually observed. Quintero and associates developed a classification for assessing disease severity. In stage I, oligohydramnios of the donor twin is present but a fetal bladder can be visualized. In stage 11, the donor's bladder is no longer visualized. In stage m, pulsed Doppler evaluation shows absent or reversed end-diastolic velocities of the donor's umbilical arteries, reversed flow in the ductus

688

A

PART TWO OBSTETRIC SONOGAAPHY

B

c

FIGURE 29..)2 Velamentous (A) and ~nal (B) insertion of the umbilical cord via US. C: On fetal MRI, in monod1orionic twins, there is a paracentTal (solid OlTON) and marrjnal (dar:t:l!d arrow) c:ortl insertion. (From Kline-Fath B. Bahado-Singh R. Bulas D. Fundamet~td and Actvonced Fetllilmaging. Pniladelphia: 'Nolters Kluwer; 2015: Figure 7-3a.)

venosus, or pulsatile flow in the umbilical vein. TTTS is considered stage IV if hydrops is present in the recipient twin, and stage V is when one or both fetuses have died in utero. 71 In utero treatment of TITS depends on the gestational age at the time of diagnosis. If diagnosed in early pregnancy, selective termination or termination of the entire pregnancy may be considered. In the second trimester, treatment options include serial reduction amniocentesis, septostomy of the amniotic membrane, and laser or radiofrequency ablation of the anastomoses. Serial reduction amniocentesis involves removing fluid from the polyhydramniotic sac, returning it to a normal volume. The theory behind this treatment is that removing the excessive fluid decreases the pressure on the oligohydramniotic

sac and allows increased perfusion of that fetus. Since production of amniotic fluid is a continual process, serial fluid reductions are usually necessary. Amniotic membrane septostomy involves inserting a needle through the dividing membrane, essentially creating a monoamn.iotic pregnancy to allow equalization of amniotic fluid. However, since monoamniotic pregnancies carry their own inherent risks, this procedure is not widely utilized. Ablation of the placental anastomoses involves identifying the abnormal vessel connections within the placenta with a fetoscope and then ablating them with laser or radiofrequency technology (Fig. 29-33). This procedure is usually done in conjunction with reduction amniocentesis. All treatments carry risk, and varying success rates have been reponed depending on sample size and the precise technique utilized. 72" 77 Since laser therapy was first introduced as a treatment for 'ITI'S, many improvements have been made on the instrumentation and technique improving success rates. Laser therapy is now considered the treatment option of choice for TITS before 26 weeks, as it is the only therapy that addresses the underlying problem.53•77•78 A recent review of literature between 1997 to 2007 on the controversy of choosing laser therapy over serial amnioreduction for treatment of 'ITTS at 26 weeks gestation found that the survival rate after laser therapy is twice that following amnioreduction. The long-term follow-up through 6 years of age for risk of death and neurologic impairment is also stable.79

CONJOINED TWINS Conjoined twins occur in approximately 1 in 50,000 to 100,000 live births.8 Conjoined twins are classified by the conjoined (shared) body area. Thoracopagus (joined at the thorax), omphalopagus (joined at the abdominal wall), or a combination of the two constitute approximately 70% of all conjoined twins. Other varieties include craniopagus (joined at the head), pygopagus (joined at the buttocks), ischiopagus (joined at the ischia), and cephalothoracopagus (Figs. 29-34; 'Il!ble 29-3).47•81.sz

°

FIGURE 29-ll Arteriovenous anas!cmoses in twin-to-twin transfusion during laser1herapy. (From Suresh M. Shnider and Levinson's Arlesthesio (or Obstetrics. Stn ed. Philadelphia: Wolters KIIJ\.\Ier; 2012: Figure 49-2.)

29 MULTI PL.£ GESTAllONS

689

c

D

E

G

H

FIGURE 29-34 Possibilities for partial fusion of fetuses. A-C: craniopagus; D-G: thoracopagus; H. I: pygopagus. (alnlinued)

690

PART TWO OBSTETRIC SONOGAAPHY

FIGURE 29-34 (continued) J-0: More complete tOnns of conjoined twinning. (!Tom Patten aM. Human Embryology. New York: McGraw-Hill; 1968.)

TABLE 29-3 Cluslflcatlon of ConJoined Twins 'lllrata Cldedw,ma

'lllrataAnadw,ma

'lllrata AnacatadlciJma

joined by lower part of body, or twins single in lower body and double in upper body a. Pygopagus: back to back. coccyx and saaum joined b. Ischiopagus: inferior parts of coccyx and saaum fused; separate vertebral columns lying in same axis c. Dicephalus: two separate heads on one

Single in upper body and double in lower body, or joined by some body part a. Cephalopagus: fused in 1he cranial wu!t b. Syncephalus: united at the face; may also be joined by thorax (cephalothoracopagus) c. Dipygus: single head, thorax, and/or abdomen; pelvis, external genitalia, and limbs are duplicate

United at midpoint of body a. Thoracopagus: atlllched along part of thoracic wall; thoracic and abdominal ~s may be abnormal b. Omphalopagus: atlllched from umbilicus to xiphoid cartilage c. Rachipagus: attached at the vertebral column above the sacrum

body d. Diprosopus: two filces with one head and one body

19 MULTIPLE GESTAllONS

Monochorlonlc/monoamnlotlc: gestation Incomplete embryonic: dMs!on after 13th day (Carnegie stageS)

Same sex (70% are female) Lack of vlsualtzadon of a separating membrane Inability to separate the fetal bodies or heads despite positional changes Mon! than three vessels in a sin&fe umbilical cord Complex fetal structural

anomalies Polyhydramnios

691

Developmentally, conjoined twins arise from monochorionic/ monoamniotic gestations with incomplete division of the embryo oc~ after the 13th day of conception during Carnegie stage 5. 1 They are always of the same sex, and 70% are female. There are no known genetic or environmental factors that result in conjoined twins. 83 Sonographic findings in conjoined twins include lack of visualization of a separating membrane between the twins, inability to separate the fetal bodies or heads (Figs. 29-35 and 29-36) despite changes in fetal position, more than three vessels in a single umbilical cord, and complex fetal structural anomalies.84 Polyhydramnios is more common in conjoined twins, occurring in approximately 50% of cases.80 Diagnosis has been made as early as 7 weeks. Early suspicion of conjoined twins should be followed up with subsequent imaging due to a high false-positive rate.as

A

B

c FIGURE 29-35 Conjoined twins diagnosed at 8 weeks. A: N. 8 weelcs gestlltion, twins (short OITOWS) are seen to be conjoined at their rumps Qong QI'ITN(). B: H. 12 weeks, the twins' bladders appear to be joined (arraN). C: Cross section of the conjoined abdomens ;rt 19 weeks, with dilatation of the shared bladder (arraN). (From Doubilet PM, Benson CB.AtlasofU/trasoundin Obstetrics and Gynecology. 2nd ed. Philadelphia: Wolters Kluwer; 2011: Figure 21.4-1.)

692

PART TWO OBSTETRIC SONOGAAPHY

B

FIGURE 29-36 Twins conjoined from the thorax to the peNis. A: Transverse view through conjoined twin thoraces (S I = spine or twin I, Sl = spined twin 2) demonstrates separam hearts (arrows) 1hat were seen beating on real-time sonography. There is a larie pericaroial effusion {-) around 1he heart d twin 2. B: Transverse view through the twins' conjoined lower abdomens. C: Transverse V.fffl 1hrough 1he twins' conjoined pelvises shows 1hat 1hey have separate bladders (OIWti!S). (!Tom Doubilet PM, Benson CB. Arias ofUltrastJund in Obstetrics and Gynemlogy. 2nd ed. Philadelphia: 'Nolters Kluwer. 20 II: ligure 21.4-3.)

Most conjoined twins are born prematurely and ap· proximately 60% die in utero or are stillbom.85 Survival of conjoined twins ultimately depends on the organs shared, particularly the heart. Seventy-five percent of thoracopagus twins share a heart and thus are not candi· dates for successful separation (Fig. 29-37).86 Sharing of brain tissue in craniopagus twins is also associated with poor outcomes. Conjoined twins can occur in higher-order gestations as well.87 3-Dimensional ultrasound (Fig. 29-36} or magneticreso· nance imaging (MRI) may be useful adjuncts to conventional

ultrasound when attempting to detennine the extent of organ involvement in conjoined twins. Another form of abnormal twinning is the parasitic twin found within the abdomen of its sibling. This is referred to as fetus in fetu,88 and should not be confused with a teratoma. Although the distinction between a parasitic twin and a teratoma may be difficult, it is an important point to establish, because teratomas have a definite ma· lignant potential, whereas the fetus in fetu is technically a hamartoma and entirely benign. Fetus in fetu occurs more commonly in the upper retroperitoneum, whereas teratomas

19 MULTIPLE GESTAllONS

693

FIGURE 29-37 Conjoined thoracopagus twir& at 20 weelcs. A:. On axial ultrasound, a sirWe liver (L) is identified in the midline. Note two stomachs (s). A and 6 represent twins. B: Color Doppler demonstr.lling a single heart shared between the two twins. C.: T2 MRI image confinns single heart (solid arrow) and fused liver (dotted aJT(IN). D: Color photo af the twins at birth. (From Kline-F.rth 8, Bahado-Singh R. Bulas D. Fundamenld and AciYanced FewllmCJI!ng. Philat:lelphia: Wolters Kluwer. 2015: Rgure 11-40.)

A

B

FIGURE 29-38 Transverse sonogram shows conjoining ci twins across the anrerior abdomen (/eng omN~). 1Wo fetal spines (short amlWS) image posteriorly.

694

PART TWO OBSTETRIC SONOGAAPHY

usually arise in the lower abdomen, most commonly in the ovaries or the sacrococcygeal region. Also, there is usually radiographic or at least microscopic evidence of a vertebral column in a fetus in fetu.

MONOAMNIOTIC TWINS Monoamniotic twins account for approximately 1% of all MZ twin gestations. This type of twinning is at highest risk. In the past, a monality rate of up to 70% has been reponed; however, multiple recent studies have suggested a substantially improved perinatal survival, reporting only 10% to 20% mortality.n.st,89-91 Fetal death is usually the result of TITS, cord entanglement, or pretenn birth. Congenital anomalies occur in monoamniotic twins in 20% of casee.92. Monoamniotic twins may be diagnosed eonographically in the absence of an intertwin membrane; however, thin membranes may be present but difficult to visualize sono· graphically, so this is not always a reliable sign. Color and pulsed Doppler can be utilized to identify cord entangle· ment and confirm one amniotic cavity (Fig. 29·39) .89 Color Doppler demonstrates multiple entangled vessels (Fig. 29-40), while pulsed Doppler should be able to document two separate heart rates. Cord entanglement is not always as· sociated with a poor outcome. Rodis and colleagues reported a 100% live birth rate and 92% perinatal survival rate in 13 monoamniotic twin gestation diagnoses with cord en· tanglement.93 Early delivery is often recommended in cases of monoamniotic twins.

A

FIGURE 2.9-40 Color Doppler snowing entangled umbilical cords in a monod'lorionic:-/monoamniotic twin ge5tation.

SELECTIVE REDUCTION Should serious complications occur or serious anomalies be detected in multiple gestations, selective termination may be offered to the parents as an option. In cases where only one twin is affected with a serious chromosomal or congenital anomaly, or when decreasing the number of fetuses in a multifetal pregnancy might improve the perinatal result, selective termination of fetuses may be a reasonable alter· native. This procedure usually involves the direct injection

B

FIGURE 1N9 A: Monoamnictic gestation with single yolk sac at 10.5 weeks. A: Yolk sac {YS) and single amnion (Am). 8: Two adjacent fetl.lses are nearly toudli~. C: Color-flow Doppler image shows two adjacent umbilical

c

cords. (!Tom Kline-Fatn B, Bahado-Singh R. Bulas D. Fundamerltoi ond Advr:tr~Cf!d Fettlll~ng.

Philadelphia: 'Nolters Kluwer: 201 S: ligure 11-36.)

19 MULTIPLE GESTAllONS

of potassium chloride into the fetal heart or umbilical vein of the designated twin. Selective tennination should be performed only in dichorionic pregnancies. If selective termination is performed on a monochorionic pregnancy or if spontaneous fetal demise occurs in a monochorionic pregnancy, the potential exists for a thromboembolic substance to be released from the dead twin, passing into the surviving twin.. and causing intrauterine disseminated intravascular coagulation (DIC) with potential brain and

SUMMARY

• Multiple births increase because of delayed childbearing, race, genetics, environmental factors, and the use of ART. • Clinical findings that raise suspicion for a multiple pregnancy are maternal larger gestational age (LGA), finding multiple heart tones, and a MSAFP level of greater than 2.5 MOM. • MZ twinning is a random event of ovum division after fertilization. • DZ twinning is influenced by genetic factors, environmental factors, AMA, and the use of ART and is the result of two ova fertilization. • 1\vo placentas and membrane sets occur with DZ twin gestations, resulting in a dichorionic/diamniotic configuration. • MZ placentation and the number of membranes depends on the timing of the division of the ovum with membrane configurations of dichorionic/diamniotic, monochorionic/dichorionic, monochorionic/ monoamniotic. • Complications of a multiple pregnancy include preterm birth, IUGR, fetal anomalies, fetal death, low birth weight, preeclampsia, placental abruption, hypertension, placenta previa, and postpartum hemorrhage. • Number and chorionicity can be determined in the first trimester; however, as many as 20% of twin pregnancies result in a singleton delivery (vanishing twin). • The twin peak sign is a lambda-shaped (A.) extension of two fused placentas between the membranes, while aT-sign describes the membrane appearance with one placenta and two amnions. • Fom layers of fetal membranes in a pregnancy before 26 weeks, two chorions and two amnions, are described as a thick membrane ("' 1.5 mm), while a thin membrane (Singh R. Bulas D. FundametttDI and Actvonced FetQf Imaging. Philadelphia: Wolters Kluwer: 2015: Rgure 18a-2.)

FIGURE 30-1 Grade Ill placenta with calcifications. (Image courtesy of Philips Healtt1care, Bothell, WA.)

Nonstress Testing A nonstress test (NST) or cardiotocography measures the fetal heart rate (FHR) in response to fetal movement over time and is the most common cardiotocographic method used to assess fetal well-being. Abnormal FHR patterns suggest heart failure and serve as an indirect measurement of central nervous system integrity and function. There is a direct relationship between hypoxemia and a decrease in FHR variability. This relationship rationalizes NST use as a screening tool for a fetus's well-being.11•41 Although a nurse specialist routinely conducts NSTs, knowledge of interpreting the test is important for sonographers. Baseline FHR and any changes that occur in response to fetal movement are recorded. A normal or reactive test occurs when there are two or more accelerations within 20 minutes (Figure 3o-4). An abnormal or nonreactive NST is defined by a lack of two or more accelerations detected in 40 minutes (Figure 30-5).5 ~.54 Studies have found that the rate of stillbirth for fetuses being evaluated after a reactive NST was 1.9 per 1,000 compared with 26 per 1,000 for a nomeactive NST. The optimal frequency of NSTs is based on clinical judgment as well as individual situations. Testing can be performed daily if there is a significant concern

705

30 INTRAUTERINE GROWTH RESTRICTION

enough amniotic fluid, assessments should become more frequent or delivery may need to be considered no matter what the score of the BPP was. A decrease in amniotic fluid is a result of a reduction in fetal blood and reduced fetal urine production as an effect from hypoxemia. The rate of stillbirth after a reassuring BPP is 0.8 per 1,000. Studies have found a reduced perinatal mortality rate in high-risk pregnancies that had BPP testing compared with others.41·S4 However, Lalor and coworkers found that evidence from randomized controlled trials does not support the use of BPP when testing fetal well-being in high-risk pregnancies. The BPP does appear to have some value and is still used to monitor the growth-restricted fetus, but further evaluation should be done to indicate the impact of the BPP on other interventions, neonatal morbidity, length of hospitalization, and parental satisfaction.ss There are varying opinions of when the BPP should be considered and how often it should be done depending on different institutions. Weekly or biweekly BPPs are often the most common practice. Performing a BPP should be considered at a gestational age when extra-utering survival is considered feasible.

nonreactive

negative

20min.

FIGURE 3G-4 Outline for conduding the non~ rest. (From Everilion LR. Gauthier Rj, Sdlitrin BS, et al. Antepart\.m fetal heart rate testing. I. Evolution d the nonstress test. /om) Obstet GjneSO%), porencephalic cysts, choroid plexus papilloma, Dandy-Walker malformation, and brain calcifications. Conunon supporting features include vertebral abnormalities, especially in the thoracic region; costal abnormalities; and eye malformations, including microphthalmia.3-'.S·6.&

Genetics of amniotic band sequence are not known,M as the gene presentation of the fetus is karyotypically normal.4 This is associated with epidermolysis bullosa and Ehlers-Danlos syndrome.3

P,.nosis In 20% of cases, diagnosis of this syndrome is made through

neonatal testing for elevated liver enzymes, thrombocytopenia, neurologic findings, and the presence of hepatosplenomegaly.5 Affected individuals have moderate to severe mental deficiency,3•6 seizures, and blindness.S.6 Mortality is high in the first few years.3•7

Amniotic Band Sequence Description .Amniotic band sequence, or constriction band syndrome, begins with the rupture of the amnion and subsequently results in the entrapment of fetal parts.9 The amnion constricts the growing fetal anatomy, leading to disruption and often am-

putation of the entangled part.3 Most cases of amniotic band sequence are idiopathic, although in rare instances trauma is the cause. The incidence bas a wide range of about 1 in 1,200 to 15,00tf live births with a male to female ratio of 1:1.3 Laboratory Values

No maternal or fetal laboratory values aid in diagnosis of this condition.

A

Sonographlc Flndlnp Severity depends on when the fetus became entrapped by the amnion.4 The presence of amniotic bands or sheets alone does not indicate amniotic band seq_uence. The entanglement of fetal structures or the obvious disruption of an extremity or other fetal part by bands or sheets is indicative of the sequence (Fig. 31-S).M Several studies link this with abnormalities such as holoprosencephaly, cerebellar dysplasia, heterotopia, and cardiac and renal abnormalities; however, a fetus with these abnormalities may have normal amnion.3 Monozygotic twins are affected more than dizygotic twins.3 Uterine synechiae or septations may mimic amniotic band sequence; however, these do not adhere to the fetus.3 PntpOSis Outcomes vary widely depending upon the nature and degree of entanglement, from minor disability associated with hands or fingers affected to death if large portions of the fetal. head or torso are entrapped in the amnion (Fig. 31-9).3

Apert Syndrome Description

Apert syndrome is a rare condition (1 in 65,000 to 200,000)3.4·6 characterized by premature fusion of the skull bones.6 A form of acrocephalosyndactyly, it was first described in 1906.M Craniosynostosis ia the main characteristic of Apert syndrome, which results in changes of head and face shape (Fig. 31-10).6 Apert syndrome is part of a group

B

FIGURE ll-8 Amniotic band syndrome. A: Marked swelli~ and edema of the foot are evident (arrows). A constriction band of1he leg is suggested (curved am:!N) B: The patnologic: photograph coJTt:lates with ultrasound findings, showing marked edema of the foot and lowef' leg secondary to constriction by amniotic: band.

728

PART TWO OBSTETRIC SONOGAAPHY

A

B

FIGURE 31-9 Anriotic band syndrome. A: A coronal SWl of1he iace and head shc.ms exencephaly with e~Ascerated brain (aRYed Cli'IOW). A facial deft (~t Cli'IOW) is also iMdent. 0, orbits. 8: A palhologic photograph d a similar case shows exencephaly, a ventral wall defect, and an amniotic: band extendifll t!Yoogh the mou1h.

of syndromes that contain craniosynostosis as a finding, along with Muenke, Crouzon, Jackson-Weiss, Pfeiffer, and Beare-Stevenson syndrome.4 Laboratory Values There are no specific maternal serum markers for Apert syndrome. In the presence of an open spinal defect, MSAFP

may be elevated.

Genetics

FGFR2 gene mutations result in Apert syndrome.4 •6 A protein produced by this gene performs multiple functio.ns, one of which is the initiation of bone development cells during embryogenesis. Lack of this protein results in the premature fusion of the skull, band, and foot bones.6 Since only one copy of the gene is necessary for development of Apert syndrome, it is considered autosomal dominant.3-'·6 This malformation occurs sporadically and has associations with advanced paternal age. 3 When a parent carries the gene, there is a 50% recurrence rate;3 however, most cases are new.4

Sonognphic Findings Prominent or bulging forehead and increased cephalic index raise suspicion for craniosynostosis (Fig. 31-ll).M The premature fusion of the skull results in sinking of the midface, wide-set eyes, and maxillary underdevelopment. 6 Other cranial findings include hypertelorism, agenesis of the corpus callosum, and ventriculomegaly.3•4 Syndactyly and digit fusion are also frequently seen in Apert syndrome.4.6 Detailed pathologic and clinical features of Apert syndrome are listed in Pathology Box 31-1. Prognosis Early surgery is often indicated to relieve increased intracranial pressure. Apert syndrome is often associated with varying degrees of mental deficiency related to the intracranial anomalies.4

Beckwith·Weidemann Syndrome

FIGURE 31-10 Typical facies of Apert syndrome. Note antimongoloid slanting of1he palpebral fiss\Jres, exophthalmos, hypertelorism, oxycephaly, and

midfacial hypoplasia.

Description Beckwith-Weidemann syndrome (BWS) is an overgrowth disorder affecting 1 in 10,000 live births.3 Diagnosis is made through five findings: macroglossia, anterior wall defects, hypoglycemia at birth, macrosomia, and hemihpyperplasia.10·n

31

A

PATIERNSOF FETALANOMAUES

B

FIGURE 31·11 Apert syndrtliTie. A: Tnis surfa.ce-rendered 3D construction demonstrates a bulging forehead and upper facial sinking. B: Proptosis, bulf}ng d the eyes, is seen in 1tlis surface rendering. Qmage courtesy of Philips Healthare, Bothell, WA.)

•

PATHOLOGY BOX Jl-l

ic and Cliniull Features of

Central nervous

Craniosynostosis with acrocephaly/system

system

turricephaly

Extremities

Agenesis/hypoplasia of corpus callosum Hydrocephalus Cephalocele Splnablftda Cerebral atrophy/hypoplasia of the white matter Gyral abnormalities, heterotopic gray matter Brachydactyly

Facial

Cardiac anomalies

Genitourinary

Broad thumbs Elbow/joint radiohumeral synostosis Hypoplastic: or absent humerus Poly.synda.c:tyfy of fingers (mitten hands) Polydac:tyly of toes Cleft palate Hypertelorism Prominent eyes/proptosis Prominent forehead (frontal bossing) Malar hypoplasia Depressed nasal bridge wfth parrotbeaked nose Pulmonic stenosis Overriding aorta

Ventricular septal defects Hydronephrosis

Reproduced witn permission from McKusick VA. eel. Online Mendelian

inheritance in man. Available at: http:/,W....W.ncbi.nlm.nih.p/omim. McKusick-Nathans II"'S!itute for Genetic Medicine, johns Hopkins University (Baltimore. MD) and National Center for Biotechnology Information. National Library of Medicine (Bethesda. MD). 2000.

Other features are renal abnormalities, visceromegaly, facial nevus tlammeus, auricular anomalies, and facial dysmorphisms.12

Laboratory Values In the fetus with BWS that has an omphalocele, there is an elevation of the maternal AFP 50% of the time.4

GenetiC's Although most cases are sporadic with normal karotypes, 10% to 15% are autosomal dominant in nature and demonstrate translocations, inversions, and/or duplications of chromosome 11. Assisted reproduction techniques have been shown to increase the incidence of BWS. These fetuses and neonates demonstrate the structural malfonnations of BWS, but do not have the genetic causes. Sonoaraphlc Findings Macroglossia3 is the classic sonographic finding in BWS,2 as with trisomy 21; however, the combination of macrosomia and macroglossia raises concern for BWS.4 Other findings

include macrosomia, omphalocele, enlarged kidneys, cardiomegaly, placenta chorioangioma, and polyhydramnios {Fig. 31-12) .uu Normal karyotype is common with a fetus demonstrating an omphalocele-containing liver.4 Detailed pathologic and clinical features of BWS are listed in Pathology Box 31-2. Prognosis

Infant mortality rates as high as 21 % due to congestive heart failure have been reported. 3•4 There is also an increased risk for pediatric neoplasia such as Wilms tumor, hepatoblastoma, adrenocortical carcinoma, neuroblastoma, and rhabdomyosarcoma.4.11

Caudal Resression Syndrome Description

Caudal regression syndrome, also known as caudal dysplasia sequence, was thought to be related to sirenomelia. 13 It is now felt to represent two distinct anomalies. The cause of this disorder is unknown; however extremes of temperature, x-rays, and drugs (lithium, sulfamides) have all proven to be inductive of this malformation and approximately 16%

730

PART TWO OBSTETRIC SONOGAAPHY

Sonographic Findings See Chapter 22 for a detailed description of the sonographic features of caudal regression syndrome. Laboratory Values Open spinal defects and some types of teratomas, both of which may be seen in this condition, may result in an increase in MSAFP.

Genetics This autosomal-dominant trait, which has an association with an anterior meningocele, presacral teratoma, and anorectal anomalies, is often referred to as the Currarino triad. 16•17 A specific genetic cause had not been established; however, the syndrome has been linked to deletions in the 6q25.3, 7q36, and HLBX9 gene.6•16.17 FIGURE 31-12 Tl'lll'lSVerse abdomen demonstrating an omphalocele. Qmage courtesy cl Philips Health care, Bolhell, WA)

·~ Growth

Craniofadal

Macrosomia

Hemlhypei'G'Ophy Metopic ridge l..arge fontanel Prominent oc.c:lput Coarse facial features Prominent eyes

Unear earlobe creases Abdomen

Metabolic

Hormonal Genitourinary

Posterior helical Indentations Macroslossia Omphalocele HepatomepJy P.a.ncreatic hyperplasia Hepatoblastoma Adrenal carcinoma Neonatal hypoglycemia Adrenocortical cytomegaly Pituitary amphophil hyperplasia Renal medullary dysplasia Large kidneys OverJrowth of extemal genitalia Cryptorchidism

Wilms tumor Gonadoblastoma Cardiovascular

Cardiomyopathy Cardiomegaly

Reproduced wi1t1 pennission from McKusic:k VA. ed. Online Mendelian inheritance in man. Available at: htlp:/,WWW.ncbi.nlm.nih.gov/omim.

McKusick-Nathans lnstihrte for Genetic Medicine, Johns Hopkins University (Baltimore, MD) and National Center for Biotechnology Information, National Library of Medicine (Bethesda, MD), 2000.

have been associated with diabetic mothers.3•1us Caudal defects vary from incomplete development of the sacrum and lumbar vertebrae to sacral agenesis and disruption of the distal spinal cord.

Prognosis How well the individual functions depends on the termination level and spinal stability. Medical problems include bladder and bowel incontinence, recurrent urinary tract infections, renal impairment, vesicourethral dysfunction, and the development of a neurogenic bladder.18•19

CHARGE Syndrome Description Previously an association, CHARGE is a collection of rare malformations now recognized as a syndrome. The pattern of anomalies includes colobomatous malformation. heart defects, atresia choanae, retardation (mental and growth deficiencies), genital hypoplasia, and ear anomalies.M Occurrence rate for CHARGE is from 1 in 8,500 to 10,000 individuals.6 Two types of characteristics help identify CHARGE syndrome. Major characteristics specific to this syndrome include the coloboma (80% to 90%),20 which is a hole in a structure of the eye. The coloboma affects eyesight, with the severity depending on the location and whether it affects one or both eyes. Eyes may be small, as may also be the nasal passages. Cranial nerve anomalies result in swallowing difficulties, facial paralysis, diminished smell, and some degree of hearing loss are common due to abnormal function. Almost all individuals have ear anomalies that include abnormal shape of the external and internal structures.6•20 Other defects, often referred to as minor defects, are nonspecific to CHARGE syndrome and may not be readily identifiable at birth. These include heart defects and cleft lip and palate. Over half the individuals demonstrate hypogonadotropic hypogonadism of external genitalia resulting in delayed puberty. A ttacheoesophageal (TE) fistula may also exist. Facial features include asymmetry and a square shape.6.z.o Laboratory Values As stated, in the fetus with an omphalocele there is an

elevation of the maternal AFP.4 Genetics This syndrome is usually a male-dominated new mutation3 resulting from a short, nonfunctional protein produced by the CHD7 gene.9.20 The remaining cases have no link to CHD7,6 with some demonstrating a translocation, deletion,

31

FIGURE 31·13 CHARGE (coloboma of the eye, heart defects, atresia of the choanae, retarded mental and growth development, genital anomalies, and ear anomalies} assodation. A: lv1 iiXial image of the fetal head at 19 weeks shows mild cerebral ventricular dilation (I I mm). 8: A follow-up exam at 36 weeks shows resolution of the ventricular dilation mel markecl polyhydramnios, nonvisible stomach, and growth restriction. H. birtt1, the infant was found to have 1he CHARGE association with d10anal atresia, colobomas, and genital anomalies.

PATIERNSOF FETALANOMAUES

731

B

A

or rearrangement on chromosome s.uo This is inheritable from a parent,6 with the severity increasing in the offspri.ng.21 Sonographic Findinp Cardiac anomalies are the most likely finding to be seen in the prenatal period. Tetralogy of Fallot, double-outlet right ventricle with an atrioventricular canal, ventricular septal defect, atrial septal defect, and right-sided and interrupted aortic arch have all been observed with CHARGE syndrome. u.2o Growth deficiencies are not usually observed in the prenatal period. Other occasional findings include micrognathia, cleft lip, cleft palate, renal anomalies, omphalocele, TE fistula, polydactyly, hemivertebrae, and hypertelorism (Fig. 31-13).20 Detailed pathologic and clinical features of CHARGE syndrome are listed in Pathology Box 31-3. Prognosis Death in the perinatal period may occur as a result of cardiac anomalies, TE fistula, or choana! atresia.20 Decreased growth and developmental delay appear in the first 6 months of life.6 Cognitive function varies with most patients exhibiting some degree of mental deficiency. 6.20 Management of CHARGE syndrome can be a challenge due to the broad range of systems affected.u

Growth

Central nerwus system/ neurologic

Cardiovascular

Craniofadal

Gastrointestinal

Goldenhar Syndrome Description

Also known as oculoauriculovertebral syndrome,3 Goldenbar syndrome is a rare condition documented in 1952 by Goldenhar, but first recorded in 18457 It is characterized by incomplete development of the ear, nose, soft palate, lip, and mandible on one side of the body.4 This is a result of the first and second brachial arch developing abnormally in the embryo.23 Because of the 65%24 occurrence of ipsilateral underdevelopment of the external ear and face, these are considered the defining features of the syndrome; however, bilateral malformations may also occur.23.24Common associated anomalies of the spine include scoliosis, hemivertebrae, and cervical fusion. 24 This syndrome occurs between 1 in 3,000 and so,ooo,M with a male-to-female ratio of 3:2.23·24

Genitourinary

Hormonal

Short stature Growth delay Dandy-Walker malformation Holoprosencephaly Mental retardation Deafness Tetralogy of Fallot Double-oudet right wntrfc:le Atrial septal defect Choana! atre.si.,tstenosis Cleft Up/palate Ear abnormalities, deafness, abnormal auditory cssides Vestibular dysfunction Temporal bone malformation Ocular abnormalities, colobomas Microcephaly Micrognathia Esophageal atre.si.,tsteno.sis Tracheoesophageal fistula Anal atresia, stenosis Omphalocele Central hypogonadism Cryptorchidism Horseshoe kidney Hydronephrosis Hypopituitarism Hypothyroidism Parathyroid hypoplasia Growth hormone deficiency

CHARGE, coloboma of1he eye, heart defects, atresia of1he choanae, retarded mental mel growth development. genital and ear anomalies. ~produced with permission from McKusick VA ed. Online Mendelian inheritance in man. Available at hllp://www.ncbi.nlm.nih.gov/omim. McKusick-Nathans Institute for Genetic Medicine, johns Hopkins University (Baltimore, MD} and National Center for Bioted1nology Information, National library of Medicine (Bethesda, MD). 2000.

732

PART TWO OBSTETRIC SONOGAAPHY

Laboratory Values

Routine maternal serum testing would not specifically diagnose Goldenhar syndrome; however, some cases of the syndrome occur with an occipital meningoencephalocele,25 which could result in an increased AFP level.4

Genetics This syndrome has a sporadic pattern and the genetics are unknown, but there has been an association with mosaic trisomy 22,4 and it is thought to be a combination of multifactorial inheritance combined with environmental factors.13 Sonographic Findings Facial anomalies such as asymmetry, cleft lip, cleft palate, and microphthalmia are frequent findinge.M Hemivertebrae or scoliosis is common. Cardiac defects such as ventricular septal defects, tetralogy of Fallot, and coarctation of the aorta-along with renal anomalies, ureteropelvic junction obstruction, and multicystic dysplastic kidney-are occasional findings {Fig. 31-14).3.4.u A study by Monni et al.26 demonstrated a thickened nuchal lucency in an embryo that had a neonatal diagnosis of Goldenhar syndrome (Fig. 31-15). Detailed pathologic and clinical features of Goldenhar syndrome are listed in Pathology Box 31-4. Prognosis Most structural abnonnalities are surgically correctable; however, the severity may lead to respiratory and feeding problems.4 Affected individuals often suffer mental deficiency,3 but have a normal life span.23

Holt-Oram Syndrome Description Also known as cardiac-limb syndrome, Holt-Oram syndrome (HOS) was first described by Holt and Oram in 1960. It is characterized by anomalies of the upper limbs and the heart6 with an incidence of approximately 1 in 100,000 live births.6 Laboratory Values

There are no known laboratory values diagnostic of HOS.

FIGURE 31-14 Color Doppler image demonstratil'l! postductal coan:talion d 1t1e aorta in a pediatric patient. (Image courtesy of Philips Healthca.re, Bothell, WA.)

Genetics HOS is an autosomal dominant mutation resulting from T-box (TBX) gene3 on chromosome 12."-6 This gene, specifically TBXS, produces instructions for the creation of the T-box protein, which attaches to other genes aiding in organ formation.6 1n embryogenesis, the T-box proteins help in the development of the upper limbs and heart through activation of genes that fonn these body parts.6 Since this protein also helps form the conduction system of the heart, its absence results in the abnonnal rhythms seen with the syndrome.6 1Iansmission of this syndrome is 100%.4 Most cases are new mutations.6

Sonographic Findings The most common sonographic findings are those affecting the upper extremities and the heart. Hand anomalies such as syndactyly (particularly between the thumb and index finger), clinodactyly, brachydactyly, and thumb anomalies are common.3.6 The malformations may be asymmetric, with the left side more severely affected. Defects of the radius, ulna, humerus, clavicle, scapula, and sternum may also be seen. Common observable cardiac anomalies include atrial septal and ventricular septal defects, bradycardia, and fibrillation, though one-third may have other types of defects.3•6 Occasional anomalies include hypertelorism, vertebral anomalies, and polydactyly. Detailed pathologic and clinical features of Holt-Oram syndrome are listed in Pathology Box 31-5. Prognosis The prognosis depends on the severity of the malformation.1 Individuals may be affected with cardiac conduction defects that may worsen with time. 3

Limb-Body Wall Complex Description Umb-body wall complex (LBWC) is a collection of ventral wall and limb defects. Two types of LBWC identified in the literature separate fetuses with and without craniofacial defects. Those with the defect demonstrate an encephalocele or exencephaly with a facial cleft and an adhesion of the anmion between the placenta and cranial defect. The second type demonstrates a short cord. intact amnion, and extraembryonic coelom persistence, as well as urogenital malformations, anal atresia, and a meningocele in the lumbosacral region.27 These malfonnations depend on the time of pregnancy when the amnion ruptures and subsequent attachment of the embryo occurs. If the rupture occurs around 5 weeks, the embryo demonstrates anencephaly, asymmetric encephaloceles, and unique facial clefts, with the placenta attaching to the head and abdomen. A rupture occurring a few weeks later results in limb reduction or limb abnormalities and thoracoabdominal malformations such as scoliosis. At the end of the first trimester and later, ruptures involve the limbs, resulting in hypoplasias, malformations, and amputation.28 Reported incidence varies widely from 1 in 7,000 to 42,000.4 .29 Laboratory Values Elevated MSAPF is seen in the second trimester.4

31

PATIERNSOF FETALANOMAUES

733

B

A

c

E

D

FIGURE 31-15 Goldenhar syndrome. A; hi axial ..new through the ortits shcms unilateral anophthalmia. 1: Coronal ..new of the face shows unilateral cleft lip/ palate(~. C: Transverse ..new d the face shows deft (arrow) and ipsilateral abnormal ear (CI.II'Ved arrow). D: Postmortem ph01Dgraph confirms the ultrasound findings. E: A post71atal computed tomographic imagedanolttef" infant with Goldenhar syndrome shows anoplhalmia.

734

Certtnl ne.rwus system/neurologic Cardiovascular Craniofacial

Skeletal Gastrointestinal

Genitourinary

PART TWO OBSTETRIC SONOGAAPHY

Upoma of the corpus callosum Hydrocephalus Cardiac defects

Unilateral ear abnormalities Unilateral deft lip/palate Preauricular tags, sinuses External auditory canal atresia Microtia Facial asymmetry, hemifacial microsomia Eplbulbar dermoid Upper eyelid coloboma Microphthalmos, anophtt!almia Macrostomia Mandibular hypoplasia Vertebral anomalies Acroosteolysls of terminal phalanges

FIGURE ll-16

This~ image of a fetl.ls with L.BW mmplex demon-

strates 1he tethering seen wi1f11his group of malformations. Qmage courtesy of

Philips Heahhcare, Bothell, WA.)

Anal atresia

Situs abnormalities Biliary atresia Esophapal atresia Tracheoesophageal flswla Ectopic and/or fused kidneys Renal agenesis Ureteropelvic: Junc:don obsa'uctlon Multlcystlc. kidney

Reproduced wi1f1 pennission lTom McKusic::k VA. eel. Online Mendelian inheritance in man. Available at: htlp:/,A.w.w.nd:li.nlm.nih.gov/omim. McKusick-Nathans lnstitllte for Genetic Medicine, Johns Hopkins University (Baltimore, MD} and National Center for Biotechnology Information, National Library of Medicine (Bethesda, MD), 2000.

Sonographic Findinp

The fetus appears "'stuck" or tethered to the placenta or uterus. with ventral wall defects. facial clefts, severe kyphoscoliosis, and limb anomalies (Fig. 31-16).4..28 Detailed pathologic and clinical features of LBWC are listed in Pathology Box 31-6. Prognosis LBWC is lethal.4.z7

Meckel-Grober Syndrome Description

Meckel-Gruber syndrome is rare and characterized by renal dysplasia, limb anomalies, and encephalocele.4 It occurs in 0.07 to 0.7 in 10,000 births, except in Finland, where the reported incidence is 1.1 in 10,000.~ There is a 1:1 ratio in males to females.28 Cardiovascular

Thorax

Skeletal

Hormonal

Atrial septal defect Ventricular septal defect Hypoplastic left heart syndrome Absent pectoralis major muscle Pectus excavatum or carfnatum Vertebral anomalies

Laboratory Values

There are no specific laboratory values to identify this syndrome; however, the presence of an encephalocele or other spinal defect could result in a high AFP.

Thoracic scoliosis

Genetics

Absent thumb Bifid thumb Triphalangeal thumb Carpal bone anomalies Upper extremity phocomelia Radial-ulnar anomalies

This disorder has a link to multiple chromosomes and is autosomal recessive.3•6.z8 Chromosome 17q224 contains the

Asymmetric Involvement Hypopituitarism

Hypothyroidism Parathyroid hypoplasia Growth hormone deficiency

Genetics

This complex is sporadic with an unknown etiology and no known genetic correlation.4

Abdome!Vchest Craniofac:ial Skeletal

Environment

Large wrttnl wall defect Craniofacial anomalies Spinal dysraphism Scoliosis Limb defects Short or absent umbilical cord Amnlodc bands

31

PATIERNSOF FETALANOMAUES

735

Meckel syndrome type 1 (.Ml

':

- -- · • · Single Umbilical Artery

7

. f -:1

~

Umbilical Cord Cysts

13

Shortened Umbs

14

-~·-:.- ..

10

9

....;

-

. .... t< -

16

. .,.-,.-

A

B

FIGURE 31-17 Trisomy lB. A: Common features. B; Karyotype showi~trisomy 19.

20

21

.... ~

~

~rj

17

..

Z!

_.- ;"-~

18

.;

·r~

Clubfoot 19

..

~-;

IS

12

II

22

X

1'

31

743

PATIERNSOF FETALANOMAUES

Laboratory Values There is no single screening test that identifies a trisomy 21 fetus. The highest detection rates occur with a combination of laboratory tests and sonography. Unconjugated estriol, PAPP-A, and AFP are !mown to be low, whereas hCG and inhibin A show elevated values (Thble 31-1) .'The cell-free fetal DNA (cffDNA) test is a relatively new test that may be used to assess the risk of a pregnant woman's developing baby (fetus) having a chromosome disorder, such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), or Patau syndrome (trisomy 13). It may be used to identify other rare conditions resulting from an extra clll'omosome or missing piece of chromosome (microdeletion). Genetics FIGURE 31·28 Ail 11-weelc fetus demons1r.lting an abnormally fttick nuchal lucency (OITllW) and an umbilical ccn:l cyst (open