Obstetric and Gynecologic Ultrasound: Case Review Series E-Book
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Description

An outstanding title from the popular Case Review Series, Obstetric and Gynecologic Ultrasound provides 119 case histories, with over 300 corresponding images, questions, answers, commentary, references, and more, to enhance your imaging interpretation skills in obstetric and gynecologic ultrasound. Its discussions incorporate the most recent knowledge from OB/GYN ultrasound literature, providing an excellent review for residents and practitioners alike.

  • Consult this title on your favorite e-reader, conduct rapid searches, and adjust font sizes for optimal readability. Compatible with Kindle®, nook®, and other popular devices.
    • Turn to Obstetric and Gynecologic Ultrasound as excellent review for the Boards!
    • Effectively prepare for certification, recertification, and practice with content that mimics the new format of board exams as well as the everyday clinical experience.
    • Review the full range of imaging findings in obstetric in gynecologic ultrasound with the addition of fetal ultrasound and high-risk-pregnancy imaging.
    • Access the most up-to-date information on fetal cardiac anomalies with expert guidance on the use of the 3-vessel view to access the outflow tracts; use of MRI in confirming and accessing fetal anomalies; ultrasound and MRI features of placenta accrete; and ultrasound evaluation of nuchal translucency, nuchal thickness, and fetal cystic hygroma.
    • Boost your skills with 119 cases organized by level of difficulty, as well as multiple-choice questions, answers, rationales, and more.

    Sujets

    Ebooks
    Savoirs
    Medecine
    Derecho de autor
    Preeclampsia
    Placenta previa
    Lesión
    Ovarian pregnancy
    Intrauterine device
    Cervical pregnancy
    Interstitial pregnancy
    Ovarian torsion
    Autosomal recessive polycystic kidney
    Walkers
    Chickenpox
    IT-101
    Choledochal cysts
    Uterus didelphys
    Ectopia cordis
    Cystic hygroma
    Vesicoureteral reflux
    Sacrococcygeal teratoma
    Abdominal mass
    Abdominal distension
    Overriding aorta
    Double outlet right ventricle
    Pericardial effusion
    Neural tube defect
    Encephalocele
    Endometritis
    Echography
    Lymphangioma
    VACTERL association
    Pseudocyst
    Transverse plane
    Complications of pregnancy
    Hydrothorax
    Agenesis of the corpus callosum
    Atresia
    Congenital diaphragmatic hernia
    Hypoplastic left heart syndrome
    Pregnancy
    Hydronephrosis
    Hydrops fetalis
    Pulmonary sequestration
    Craniosynostosis
    Ovarian hyperstimulation syndrome
    Tamoxifen
    Gastroschisis
    Abdominal wall defect
    Choroid plexus cyst
    Sex cord-gonadal stromal tumour
    Gestational trophoblastic disease
    Urinary retention
    Acute pancreatitis
    Hydatidiform mole
    Oligohydramnios
    Polyhydramnios
    Differential diagnosis
    Gastrointestinal bleeding
    Ureterocele
    Ventricular septal defect
    Congenital heart defect
    Intracranial hemorrhage
    Prenatal diagnosis
    Tuberous sclerosis
    Review
    Pre-eclampsia
    Pleural effusion
    Ovarian cyst
    Echocardiography
    Lesion
    Bowel obstruction
    Congenital disorder
    Gallstone
    Health care
    Heart failure
    Tetralogy of Fallot
    Cleft lip and palate
    Disseminated intravascular coagulation
    Porencephaly
    Hydranencephaly
    Holoprosencephaly
    Anencephaly
    Pulmonary embolism
    Hydrocephalus
    Cyst
    Esophageal atresia
    Infertility
    Karyotype
    Intrauterine growth restriction
    Bleeding
    Miscarriage
    Medical ultrasonography
    Peritonitis
    Conjoined twins
    Prune belly syndrome
    Multiple birth
    Hernia
    Appendicitis
    Edema
    Heart disease
    Obesity
    Ectopic pregnancy
    Polycystic ovary syndrome
    Endometriosis
    Gynaecology
    Obstetrics
    X-ray computed tomography
    Turner syndrome
    Infection
    Varicose veins
    Rheumatoid arthritis
    Pelvic inflammatory disease
    Estrogen
    Magnetic resonance imaging
    Muscular dystrophy
    Down syndrome
    Fractures
    Divine Insanity
    Calcification
    Encéphalocèle
    Lésion
    Placenta accreta
    Spina bifida
    Maladie infectieuse
    Copyright

    Informations

    Publié par
    Date de parution 21 janvier 2013
    Nombre de lectures 0
    EAN13 9781455753567
    Langue English
    Poids de l'ouvrage 3 Mo

    Informations légales : prix de location à la page 0,0210€. Cette information est donnée uniquement à titre indicatif conformément à la législation en vigueur.

    Exrait

    Series Editor
    David M. Yousem, MD, MBA
    Professor of Radiology Director of Neuroradiology Russell H. Morgan Department of Radiology and Radiological Science The Johns Hopkins Medical Institutions Baltimore, Maryland

    Other Volumes in the CASE REVIEW Series
    Brain Imaging, Second Edition
    Breast Imaging, Second Edition
    Cardiac Imaging
    Duke Review of MRI Principles
    Emergency Radiology
    Gastrointestinal Imaging, Third Edition
    General and Vascular Ultrasound, Second Edition
    Genitourinary Imaging, Second Edition
    Musculoskeletal Imaging, Second Edition
    Nuclear Medicine, Second Edition
    Pediatric Imaging, Second Edition
    Spine Imaging, Second Edition
    Thoracic Imaging, Second Edition
    Vascular and Interventional Imaging
    CASE REVIEW

    Obstetric and Gynecologic Ultrasound

    THIRD EDITION
    CASE REVIEW SERIES

    Karen L. Reuter, MD, FACR
    Professor of Radiology Tufts University School of Medicine Section Head Lahey Clinic Medical Center Burlington, Massachusetts

    John P. McGahan, MD, FACR
    Professor and Vice Chair of Academic Affairs Director of Abdominal Imaging University of California, Davis Health System Sacramento, California
    1600 John F. Kennedy Blvd. Ste 1800 Philadelphia, PA 19103-2899

    OBSTETRIC AND GYNECOLOGIC ULTRASOUND:
    CASE REVIEW, THIRD EDITION ISBN: 978-1-4557-4375-9
    Copyright 2013 by Saunders, an imprint of Elsevier Inc.
    Copyright 2007, 2001 by Mosby, an affiliate of Elsevier Inc.

    No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions .
    This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

    Notices
    Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.
    Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility.
    With respect to any drug or pharmaceutical products identified, readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications. It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions.
    To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.
    Library of Congress Cataloging-in-Publication Data
    Reuter, Karen L.
    Obstetric and gynecologic ultrasound : case review/Karen L. Reuter, John P. McGahan. -- 3rd ed.
    p. ; cm. -- (Case review series)
    Rev. ed. of: Case review. 2nd ed. c2007.
    Includes bibliographical references and indexes.
    ISBN 978-1-4557-4375-9 (pbk. : alk. paper)
    I. McGahan, John P. II. Reuter, Karen L. Case review. III. Title. IV. Series: Case review series.
    [DNLM: 1. Genital Diseases, Female--ultrasonography--Examination Questions. 2. Fetal Diseases--ultrasonography--Examination Questions. 3. Pregnancy Complications--ultrasonography--Examination Questions. 4. Ultrasonography--Examination Questions. 5. Ultrasonography, Prenatal--Examination Questions. WP 18.2]

    618.107543--dc23
    2012041503


    Content Strategist: Don Scholz
    Content Development Specialist: Gina Donato Publishing Services Manager: Patricia Tannian Design Direction: Steven Stave
    To the radiology residents and all those who participate in the obstetric and gynecologic care of women
    SERIES FOREWORD
    I have been very gratified by the popularity and positive feedback that the authors of the Case Review series have received on the publication of the multiple editions of their volumes. While some are still in first editions, others have third editions printed and fourth editions in the works. This speaks to the high quality of the authors and the material they have at their disposal. At the same time, the online versions available at https://casereviewsonline.com/ offer new capabilities and interaction and self-guided learning that print editions cannot provide.

    David M. Yousem, MD, MBA
    BOOK FOREWORD
    I congratulate Dr. Karen Reuter for spearheading the third edition of the Obstetric and Gynecologic Ultrasound: Case Review Series and for pulling in the experience of Dr. John McGahan, a noted educator and outstanding academician. I am happy to see the life span of this volume continue to grow in new ways with new technologies and new entities. I am sure that trainees and practicing radiologists will appreciate this contribution, as I do, to the Case Review Series . Bravo Karen and John!

    David M. Yousem, MD, MBA
    PREFACE
    This updated third edition of the case review series not only focuses on ultrasound in obstetrics and gynecology but also emphasizes the growing use of MRI in both obstetric and gynecologic imaging. In most situations, ultrasound is definitive in either documenting normal findings or delineating a specific abnormality. However, in some cases, MRI is useful in collaboration with ultrasound in establishing a diagnosis or providing other information that may be definitive. This ultrasound case series is in a new format that includes the use of multiple choice questions with more detailed explanations and discussions including the most recent medical knowledge. We have provided new cases with updated materials and the latest reference publications and cross-references to the newest edition of Ultrasound: The REQUISITES . We hope you find these cases helpful in your understanding of ultrasound imaging of obstetric and gynecologic abnormalities for optimal patient care.

    Karen L. Reuter, MD, FACR
    John P. McGahan, MD, FACR


    Because of space limitations, not all of the references have been included with each case in this book. Additional references are available at https://casereviewsonline.com/ .
    ACKNOWLEDGMENTS
    A special thank you to my husband, John; Kara and Elias, Kendra and Mark, Kristyn and Jacky (Tin Kei), and Sophia and her brother Sebastian for their loving support.
    KLR
    I would like to thank everyone who helped in preparation of this textbook. First and foremost, I d like to thank Teresa Victoria, MD, PhD, and Jeffrey C. Hellinger, MD, for supplying many of the magnetic resonance images that helped to make this text useful. Also, I would like to thank Alex Fodor, MD, Jonathan Kuo, MD, Liina Poder, MD, Simran Sekhon, MD, Holly Thompson, MD, and Luke Wright, MD, who prepared individual cases for this Case Reviews series. They certainly helped make this journey more enjoyable. Finally, I would like to thank those who helped me directly with either illustration preparation or text preparation including both Hue To and Julie Ostoich. Their hard work made my job much easier.
    JPM
    CONTENTS
    Cover Page
    Title Page
    Copyright Page
    Dedication Page
    Series Foreword
    Book Foreword
    Preface
    Acknowledgments
    Opening Round
    Fair Game
    Challenge
    Index of Cases
    Index of Terms
    Opening Round
    CASE 1

    History: A 61-year-old woman receiving long-term treatment with tamoxifen for breast cancer presents with endometrial thickness of 18 mm detected on a transvaginal sagittal image of the uterus.

    1 . What spectrum of endometrial abnormalities does tamoxifen induce? (Choose all that apply.)
    A. Polyps of the endometrium
    B. Subendometrial cysts
    C. Endometrial hyperplasia
    D. Atrophy
    2 . What is the effect of tamoxifen on the uterus?
    A. Antiestrogenic
    B. Estrogenic
    C. Progesterogenic
    3 . What is the normal thickness of the endometrium of the uterus in a patient receiving long-term tamoxifen treatment?
    A. 10 mm or more
    B. Less than 6 mm
    C. 8 to 10 mm
    4 . What is the most common endometrial pathology resulting from tamoxifen use?
    A. Endometrial hyperplasia
    B. Subendometrial cysts
    C. Polyps

    ANSWERS

    CASE 1

    Tamoxifen

    1 . A, B, and C
    2 . B
    3 . B
    4 . C

    References
    Cohen I: Endometrial pathologies associated with postmenopausal tamoxifen treatment. Gynecol Oncol . 2004; 96(2):256-266.
    http://www.ncbi.nlm.nih.gov/pubmed/15297160 (Accessed on May 29, 2012.).
    DeKroon CD, Louwe LA, Trimbos JB, et al. The clinical value of 3-dimensional saline infusion sonography in addition to 2-dimensional saline infusion sonography in women with abnormal uterine bleeding: work in progress. J Ultrasound Med . 2004; 23(11):1433-1440.
    http://www.ncbi.nlm.nih.gov/pubmed/15498907 (Accessed on May 29, 2012.).
    Fishman M, Boday M, Sheiner E, et al: Changes in the sonographic appearance of the uterus after discontinuation of tamoxifen therapy. J Ultrasound Med . 2006; 25(4):469-473.
    http://www.ncbi.nlm.nih.gov/pubmed/16567436 (Accessed on May 29, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 542, 544, 546.

    Comment

    Tamoxifen Use and Effects
    Tamoxifen is a widely used medication for patients with breast cancer because of its antiestrogenic effect on breast tissue. However, the medication can have an estrogenic effect on the endometrium, and patients are predisposed to develop numerous different endometrial abnormalities, including polyps of the endometrium and endocervix, subendometrial cysts, endometrial hyperplasia, and cancer (endometrial, malignant mixed mesodermal tumors, and sarcoma). The risk of developing one of these pathologic conditions is related to the duration of tamoxifen therapy; the most common abnormality is an endometrial polyp.

    Ultrasound Findings
    An endometrial thickness greater than 5 mm warrants follow-up. One study showed that most women receiving tamoxifen did not have symptoms such as bleeding. Nonetheless, almost half of the women had abnormal endometrial thickness on ultrasound. Less than 1% of women receiving tamoxifen therapy develop endometrial cancer even though the risk may be increased sixfold. Most women receiving tamoxifen have been doing so for more than 5 years, and most present with postmenopausal bleeding. There is a considerable reduction in endometrial thickness at 6 months after cessation of therapy. Sonohysterography is an excellent modality to delineate the endometrial contents better. Sonohysterography is the most likely imaging procedure to reveal polyps, which are the most frequent abnormality in women receiving tamoxifen treatment. Tamoxifen-related polyps tend to be larger and have an increased rate of malignant changes compared with endometrial polyps in the general population. A hyperechoic endometrium with small cystic spaces is the classic finding with tamoxifen therapy (see Figure ). Many of these cystic spaces represent endometrial polyps; however, cystic hyperplasia may also have this appearance. Two-dimensional or three-dimensional sonohysterography is often helpful to elucidate the cause of endometrial stripe thickening.
    CASE 2


    Used with permission from Anderson Publishing Ltd., from Hellinger J, et al: Fetal MRI in the third dimension. Appl Radiol 39(7)8-19, 2010. Anderson Publishing Ltd.
    History: A 28-year-old pregnant patient is referred because of an abdominal ultrasound.

    1 . What should be included in the differential diagnosis? (Choose all that apply.)
    A. Fetal ascites
    B. Hydrops fetalis
    C. Bilateral hydronephrosis
    D. Pleural effusion
    E. Duodenal atresia
    2 . Which of the following is not included in the causes of fetal pleural effusions?
    A. Nonimmune hydrops
    B. Immune hydrops
    C. Pulmonary sequestration
    D. Echogenic cardiac focus
    3 . What is the perinatal mortality rate of fetal hydrothorax?
    A. 0% to 25%
    B. 25% to 50%
    C. 50% to 75%
    D. 75% to 100%
    4 . Which of the following is a primary cause of hydrothorax?
    A. Chylothorax
    B. Chromosomal abnormality
    C. Infection
    D. Cardiovascular

    ANSWERS

    CASE 2

    Pleural Effusions

    1 . B and D
    2 . D
    3 . B
    4 . A

    References
    Aubard Y, Derouineau I, Aubard V, et al: Primary fetal hydrothorax: a literature review and proposed antenatal clinical strategy. Fetal Diagn Ther . 1998; 13(6):325-333.
    http://www.ncbi.nlm.nih.gov/pubmed/9933813 (Accessed on May 29, 2012.).
    Bianchi S, Lista G, Castoldi F, et al: Congenital primary hydrothorax: effect of thoracoamniotic shunting on neonatal clinical outcome. J Matern Fetal Neonatal Med . 2010; 23(10):1225-1229.
    http://www.ncbi.nlm.nih.gov/pubmed/20482288 (Accessed on May 29, 2012.).
    Deurloo KL, Devlieger R, Lopriore E, et al: Isolated fetal hydrothorax with hydrops: a systematic review of prenatal treatment options. Prenat Diagn . 2007; 27(10):893-899.
    http://www.ncbi.nlm.nih.gov/pubmed/17605152 (Accessed on May 29, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 270, 419-422.

    Comment

    Differential Diagnosis
    The diagnosis of pleural effusions is straightforward. Any fluid within the fetal chest is abnormal. A pleural effusion is either a primary abnormality such as chylothorax or a manifestation of a more generalized condition such as hydrops fetalis. Primary chylothorax is often a unilateral process that has an approximately equal occurrence on the right and left sides. There are multiple etiologies of fetal hydrops, including immune and nonimmune causes, but pleural effusion may be one of the earliest signs. Secondary causes of pleural effusions include infection, intrathoracic mass (congenital cystic adenomatoid malformation, sequestration), cardiovascular abnormalities, diaphragmatic hernia, chromosomal abnormalities, and various syndromes.

    Ultrasound Findings
    A pleural effusion appears as anechoic fluid noted within the pleural spaces in the thoracic cavity and above the diaphragmatic contour. This fluid surrounds the more echogenic lung (Figure A ). The fluid may be either unilateral or bilateral. Bilateral pleural effusions as in this case suggest a secondary etiology of pleural effusions, such as fetal immune or nonimmune hydrops or some other secondary etiology as listed previously. MRI can be used to evaluate the pleural effusion and help determine if there is any other underlying abnormality (Figure B ).

    Prognosis and Management
    Perinatal mortality of a fetus with a hydrothorax ranges from 35% to 50%. The two worst complications of fetal hydrothorax are development of pulmonary hypoplasia and hydrops. Development of hydrops and early delivery are associated with a poor neonatal outcome. The perinatal mortality rate of untreated hydropic fetuses was 76% in one series compared with only 25% of fetuses without hydrops. If the hydrothorax is large or clinical deterioration such as a hydropic fetus develops, fetal thoracentesis or a thoracoamniotic shunt can be considered. This treatment may not always be curative and is associated with complications, but it has been shown to be effective in some cases.
    CASE 3


    Used with permission from Anderson Publishing Ltd., from Hellinger J, et al: Fetal MRI in the third dimension . Appl Radiol 39(7)8-19, 2010. Anderson Publishing Ltd.
    History: A patient presents for a routine second-trimester ultrasound.

    1 . What should be included in the differential diagnosis? (Choose all that apply.)
    A. Enteric duplication cysts
    B. Mesenteric cysts
    C. Ovarian cysts
    D. Choledochal cysts
    E. Renal cysts
    2 . Which of the following is not included in the ultrasound findings in a fetus with ovarian cysts?
    A. The cysts are usually bilateral.
    B. The cysts may be seen in the upper abdomen.
    C. The cysts may undergo torsion.
    D. Most cysts are purely cystic.
    3 . In regard to treatment of fetal ovarian cysts, which of the following statements is not true?
    A. After delivery, observation alone is considered appropriate therapy.
    B. Uncomplicated ovarian cysts usually resolve spontaneously.
    C. Prenatal cyst aspiration should not be performed.
    D. If ovarian torsion is present, surgery should be considered.
    4 . Which of the following statements is not true?
    A. Ovarian cysts may result in fetal ascites.
    B. In the newborn, enteric duplication cysts are rarely symptomatic.
    C. Type I choledochal cysts are the most common type.
    D. Omental cysts may have a variety of appearances.

    ANSWERS

    CASE 3

    Ovarian Cyst

    1 . A, B, and C
    2 . A
    3 . C
    4 . B

    References
    Ak n MA, Ak n L, Ozbek S, et al: Fetal-neonatal ovarian cysts-their monitoring and management: retrospective evaluation of 20 cases and review of the literature. J Clin Res Pediatr Endocrinol . 2010; 2(1):28-33.
    http://www.ncbi.nlm.nih.gov/pubmed/21274333 (Accessed on May 29, 2012.).
    Dimitraki M, Koutlaki N, Nikas I, et al: Fetal ovarian cysts: our clinical experience with 16 cases and review of the literature. J Matern Fetal Neonatal Med ; 2011 May 26.
    http://www.ncbi.nlm.nih.gov/pubmed/21615230 (Accessed on May 29, 2012.).
    Galinier P, Carfagna L, Juricic M, et al: Fetal ovarian cysts management and ovarian prognosis: a report of 82 cases. J Pediatr Surg . 2008; 43(11): 2004-2009.
    http://www.ncbi.nlm.nih.gov/pubmed/18970932 (Accessed on May 29, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, p 447.

    Comment

    Differential Diagnosis
    The differential diagnosis for a fetal cystic abdominal or pelvic mass is large. The location of the mass is important in the differential diagnosis. In this case, the mass is not located close to the kidneys, so hydronephrosis and bladder outlet obstruction are not strong considerations. Choledochal cysts are quite rare and usually seen in the right upper quadrant of the abdomen associated with the biliary ductal system. In this case, the cyst is not within the liver or spleen, and splenic or liver cysts are excluded. Meconium pseudocysts occur as a cystic abdominal mass but usually not until later in pregnancy. Urachal cysts are usually near the umbilical cord insertion site, and they can communicate with the urinary bladder. Umbilical vein varices are a dilation of the umbilical veins seen with color flow imaging.
    Ovarian cysts are the most common cystic abdominal mass in female fetuses (Figures A and B ). With improved fetal imaging, more ovarian cysts are being diagnosed. Other differential diagnoses that may be considered include mesenteric or omental cysts. Another simple cyst that may be included in the differential diagnosis is an enteric duplication cyst, which is located adjacent to the bowel (Figure C ).

    Ultrasound Findings
    Ovarian cysts are typically benign functional cysts that result from enlargement of otherwise normal follicles. These cysts usually are less than a few millimeters and are too small to be visualized, but with hormonal stimulation of the ovary by the placenta and maternal hormones, larger cysts may develop. These cysts are usually unilateral and cystic. They are usually small, but they may become quite large-greater than 5 cm and in reported cases 8 to 10 cm (Figures A and B ). These cysts may become complex and have a fluid debris level, a retracting clot, or internal septation usually from ovarian torsion (Figure C ). Ascites has been associated with ovarian cysts, thought to be secondary to torsion or rupture of the cysts. Polyhydramnios has been reported in a few cases, probably secondary to small bowel obstruction by mechanical compression by these cysts.

    Prognosis and Management
    Birth dystocia, respiratory distress, and gastrointestinal obstruction have been reported with very large cysts. A few cases of prenatal aspiration have been reported. After delivery, management is usually observation alone. An intervention such as oophorectomy has been performed when there is a complication of the cyst such as ovarian torsion. Oophorectomy may be performed if there are symptoms in the neonate such as abdominal distention by the cyst or mechanical obstruction of the bowel resulting in vomiting. Additionally, cystectomy with salvage of the remainder of the ovary has been performed. Overall prognosis is usually good. Other associated anomaly with fetal ovarian cyst is rare. Rare cystic neoplasms of the ovary in the fetus have been reported.
    CASE 4


    Used with permission from Anderson Publishing Ltd. from Victoria T, et al: Fetal MRI of common non-CNS abnormalities: a review. Appl Radiol 2011;40(6)8-17. Anderson Publishing Ltd.
    History: A patient presents with an abnormality identified on an ultrasound obtained at 18 weeks gestation at an outside institution.

    1 . What should be included in the differential diagnosis? (Choose all that apply.)
    A. Bilateral ureterovesical junction obstruction
    B. Bilateral ureteropelvic junction (UPJ) obstruction
    C. Posterior urethral valves
    D. Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS)
    E. Bilateral multicystic dysplastic kidneys
    2 . Which of the following statements regarding UPJ obstruction is not true?
    A. The renal pelvis can enlarge to a massive proportion and produce an abdominal cyst.
    B. Rupture of the renal pelvis calyx results in urine ascites or perinephric urinoma.
    C. UPJ obstruction is more commonly a bilateral process.
    D. UPJ obstruction can be associated with renal dysplasia.
    3 . Which of the following statements regarding the treatment of UPJ obstruction is not true?
    A. Double-J pigtail stent placement is commonly used for the relief of obstruction in utero.
    B. In utero follow-up scans are performed to reassess the degree of hydronephrosis and amniotic fluid volume.
    C. After delivery, if surgery is performed, pyeloplasty would be the surgery of choice.
    D. Poor prognostic indicators include development of a perinephric urinoma or development of a large abdominal cyst.
    4 . Which of the following entities is associated with the best prognosis?
    A. MMIHS
    B. Posterior urethral valves
    C. Urethral atresia
    D. UPJ obstruction

    ANSWERS

    CASE 4

    Ureteropelvic Junction Obstruction

    1 . A, B, C, and D
    2 . C
    3 . A
    4 . D

    References
    Al-Shibli AI, Chedid F, Mirghani H, et al: The significance of fetal renal pelvic dilatation as a predictor of postnatal outcome. J Matern Fetal Neonatal Med . 2009; 22(9):797-800.
    http://www.ncbi.nlm.nih.gov/pubmed/19557659 (Accessed on May 30, 2012.).
    Bethune M. Literature review and suggested protocol for managing ultrasound soft markers for Down syndrome: thickened nuchal fold, echogenic bowel, shortened femur, shortened humerus, pyelectasis and absent or hypoplastic nasal bone. Australas Radiol . 2007; 51(3):218-225.
    http://www.ncbi.nlm.nih.gov/pubmed/17504311 (Accessed on May 30, 2012.).
    Chertin B, Pollack A, Koulikov D, et al: Conservative treatment of ureteropelvic junction obstruction in children with antenatal diagnosis of hydronephrosis: lessons learned after 16 years of follow-up. Eur Urol . 2006; 49(4):734-738.
    http://www.ncbi.nlm.nih.gov/pubmed/16504374 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, p 465.

    Comment

    Differential Diagnosis
    A cystic structure is noted in the retroperitoneum in the location of the fetal kidneys. First, it must be determined if this cystic structure is a cystic mass, such as a multicystic dysplastic kidney, or if it is hydronephrosis. With hydronephrosis, the cystic structure representing the dilated renal pelvis connects to the prominent calyceal system, making diagnosis of hydronephrosis easier (Figures A and B ). Unilateral UPJ obstruction is more common than bilateral. Bilateral hydronephrosis can occur with bilateral UPJ obstruction (Figure A ). In this entity, the bladder is normal in size. Similarly, with bilateral vesicoureteric junction obstruction, the bladder is normal in size, but there are bilateral dilated ureters. Vesicoureteric reflux could be considered; this entity can have varying amounts of dilation of the ureter and pelvis from side to side. Reflux is a common problem in the newborn.
    Posterior urethral valves and urethral atresia result in a large, thick bladder wall. With posterior urethral valves, the bladder neck has a keyhole appearance. There is usually severe hydronephrosis and often oligohydramnios in both conditions. Rare causes of bilateral dilation of the renal pelvis and ureters include bilateral ureteroceles or MMIHS.

    Ultrasound Findings
    Dilation of the renal pelvis is seen with UPJ obstruction. The degree of dilation has been classified using pelvic diameter and the stage in pregnancy. The degree of caliectasis can also be determined as none, moderate, or marked (Figure C ). When there is a question of dilation of the renal pelvis, postnatal ultrasound is essential to determine the degree of renal tissue. Several grading systems of fetal renal pelvic dilation have been suggested, but there is no consensus regarding any specific grading system. Fetal MRI may be helpful to obtain a better overview of the severity of hydronephrosis and other abnormalities (Figure D ).
    Evaluation of the contralateral kidney for any abnormality is also helpful. Contralateral renal anomalies are uncommon; they occur in 20% of cases of UPJ obstruction and include bilateral UPJ obstruction, contralateral multicystic dysplastic kidney, and, more rarely, renal agenesis. The most important prognostic factor in terms of fetal or neonatal survival is the presence of a normal amount of amniotic fluid.

    Prognosis and Management
    Management includes follow-up prenatal ultrasound scan to determine the amount of renal pelvis dilation and the presence of caliectasis. Most important, prenatal management includes determining whether the amount of amniotic fluid is normal. After delivery, most cases are managed conservatively unless hydronephrosis is increasing or renal function is poor.
    CASE 5


    History: A pregnant patient presents for a routine 20-week ultrasound scan.

    1 . Which of the following would be included in the differential diagnosis? (Choose all that apply.)
    A. Ventriculomegaly
    B. Choroid plexus cyst
    C. Intracranial hemorrhage
    D. Semilobar holoprosencephaly
    E. Dandy-Walker malformation
    2 . Which of the following is not a true statement concerning choroid plexus cyst?
    A. These cysts are most frequently benign findings.
    B. These cysts are often transient findings and resolve by the third trimester.
    C. These cysts may be either unilateral or bilateral.
    D. These cysts are associated with an increased risk of hydrocephalus.
    3 . Choroid is present in all portions of the lateral ventricles except :
    A. The frontal horn of the lateral ventricle
    B. The body of the lateral ventricle
    C. The trigone of the lateral ventricle
    D. The temporal horn
    4 . Which chromosomal abnormality is most commonly associated with choroid plexus cysts?
    A. Trisomy 13
    B. Trisomy 18
    C. Trisomy 21
    D. XO karyotype

    ANSWERS

    CASE 5

    Choroid Plexus Cyst

    1 . A, B, and C
    2 . D
    3 . A
    4 . B

    References
    Beke A, Barakonyi E, Belics Z, et al: Risk of chromosome abnormalities in the presence of bilateral or unilateral choroid plexus cysts. Fetal Diagn Ther . 2008; 23(3):185-191.
    http://www.ncbi.nlm.nih.gov/pubmed/18417976 (Accessed on May 30, 2012.).
    Bethune M: Time to reconsider our approach to echogenic intracardiac focus and choroid plexus cysts. Aust N Z J Obstet Gynaecol . 2008; 48(2):137-141.
    http://www.ncbi.nlm.nih.gov/pubmed/18366485 (Accessed on May 30, 2012.).
    Fong K, Chong K, Toi A, et al: Fetal ventriculomegaly secondary to isolated large choroid plexus cysts: prenatal findings and postnatal outcome. Prenat Diagn . 2011; 31(4):395-400.
    http://www.ncbi.nlm.nih.gov/pubmed/21328578 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 395-397.

    Comment

    Differential Diagnosis
    This case shows a well-demarcated hypoechoic structure within both lateral ventricles. This structure is a classic finding for a choroid plexus cyst. The most common differential diagnosis to consider would be intraventricular hemorrhage, which may result in a blood clot that eventually cavitates and becomes hypoechoic. However, intraventricular hemorrhage usually occurs late in the second trimester or early in the third trimester. Choroid plexus cysts are usually observed on a screening ultrasound scan in the 18th to 20th week of gestation. Although unusual large and bilateral, choroid plexus cysts could be mistaken for ventriculomegaly. Choroid plexus cysts by themselves rarely cause ventriculomegaly; however, they may be so large that they mimic ventriculomegaly. In this case the feature of well-demarcated hypoechoic structures within the echogenic choroid of the lateral ventricles is almost pathognomonic of a choroid plexus cyst.

    Ultrasound Findings
    The diagnosis of choroid plexus cyst is straightforward and includes a well-demarcated hypoechoic structure with a well-defined wall within the echogenic choroid of either the downside or upside lateral ventricle. The cysts are more commonly identified in the downside lateral ventricle because the overlying skull reduces visualization of the upside lateral ventricle. The cyst may be unilateral or bilateral and can be multiple (see Figure ). The definition of choroid plexus cyst is usually a cyst greater than 2 mm in diameter in the choroid. Often there is some normal heterogeneity of the choroid plexus, which should not in itself be called a choroid plexus cyst.

    Prognosis and Management
    In the absence of an associated anomaly, a choroid plexus cyst should be considered a normal anatomic variant. Parents are often concerned about fetal cysts in the brain, but they should be reassured that these cysts are usually normal and decrease rapidly in size by the third trimester. Remnants of the cyst are only rarely identified after birth.
    Although choroid plexus cysts are benign, this transient finding is associated with increased risk of trisomy 18. When a choroid plexus cyst is identified, careful scanning of the fetus should be performed. The patient should be reassured that in most cases these cysts are benign and do not affect outcome. With the use of high-quality ultrasound equipment, choroid plexus cysts are probably detected more frequently than previously.
    When a choroid plexus cyst is detected, the patient s age and biochemical marker values should be reviewed. In addition, a targeted ultrasound examination should be performed to check for potential abnormalities associated with trisomy 18. Trisomy 18 is also known as trisomy E or Edwards syndrome.
    CASE 6



    History: A pregnant patient presents with a prior history of an abnormal fetus.

    1 . What should be included in the differential diagnosis of Figures A and B ? (Choose all that apply.)
    A. Fetal tachyarrhythmia
    B. Fetal anemia
    C. Fetal cystic hygroma
    D. Chromosomal abnormalities
    E. Rh incompatibility
    2 . Which of the following statements concerning fetal hydrops is not true?
    A. Rh incompatibility is the most common cause of fetal hydrops.
    B. Nonimmune hydrops is associated with two or more areas of body cavity effusion.
    C. Fetal hydrops includes one or more sets of body cavity effusions plus anasarca.
    D. Cardiac anomalies are an etiology of nonimmune fetal hydrops.
    3 . Which of the following statements concerning fetal cystic hygroma is not true?
    A. Fetal cystic hygromas usually result from failure of communication of the thoracic duct with the jugular veins.
    B. Septated cystic hygromas have a better prognosis than nonseptated hygromas.
    C. Cystic hygromas may be associated with XO karyotype.
    D. Fetal cystic hygromas often result in fetal demise.
    4 . Which of the following statements concerning Turner syndrome is not true?
    A. Turner syndrome is associated with coarctation of the aorta.
    B. Turner syndrome is associated with horseshoe kidneys.
    C. Ovarian dysgenesis is associated with Turner syndrome.
    D. Adult patients with Turner syndrome have normal stature.

    ANSWERS

    CASE 6

    Cystic Hygroma and Fetal Hydrops

    1 . A, B, C, D, and E
    2 . A
    3 . B
    4 . D

    References
    Ganapathy R, Guven M, Sethna F, et al: Natural history and outcome of prenatally diagnosed cystic hygroma. Prenat Diagn . 2004; 24(12):965-968.
    http://www.ncbi.nlm.nih.gov/pubmed/15614877 (Accessed on May 30, 2012.).
    Has R. Non-immune hydrops fetalis in the first trimester: a review of 30 cases. Clin Exp Obstet Gynecol . 2001; 28(3):187-190.
    http://www.ncbi.nlm.nih.gov/pubmed/11530871 (Accessed on May 30, 2012.).
    Tanriverdi HA, Hendrik HJ, Ertan AK, et al: Hygroma colli cysticum: prenatal diagnosis and prognosis. Am J Perinatol . 2001; 18(8):415-420.
    http://www.ncbi.nlm.nih.gov/pubmed/11733855 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 406-410, 419-422.

    Comment

    Differential Diagnosis of Neck Mass
    In this case two differential diagnoses must be considered. The first is the fetal neck mass. The differential diagnosis of a fetal neck mass includes cystic hygroma, neck tumor, or encephalocele. In this case, however, skin thickening and fluid collection in other cavities are also present. The most likely diagnosis in this case is a fetal cystic hygroma. Fetal cystic hygroma has many different names, including diffuse lymphangiectasia, diffuse lymphangioma, hygroma colli, and hygroma cysticum. Primitive lymphatic sacs located lateral to the jugular vein develop in utero. Right and left thoracic ducts join the jugular sacs with the cisterna chyli. Failure of communication between these primitive structures and the jugular veins results in accumulation of lymphatic fluid in the jugular lymphatic sacs and tissue, giving the appearance of a cystic hygroma. This condition is often associated with a thick fibrous band called a nuchal ligament . When a nuchal ligament is present, the prognosis is much worse and includes an increased risk of aneuploidy, hydrops, other anomalies, and pregnancy loss.

    Differential Diagnosis of Fetal Hydrops
    The differential diagnosis of fetal hydrops is large and includes both immunologic and nonimmunologic causes of hydrops. In the United States with effective prophylaxis against Rh immunization, most cases of fetal hydrops are nonimmune. The many etiologies of nonimmune hydrops include high-output cardiac failure, obstruction of venous return (e.g., congenital cystic adenomatoid malformation or congenital pulmonary airway malformation [CPAM]), decreased plasma oncotic pressure with decreased albumin formation, increased capillary permeability such as with a congenital infection, and obstruction of lymphatic flow such as in this case with cystic hygroma.

    Ultrasound Findings
    Ultrasound findings of cystic hygroma include a septated or nonseptated neck mass, usually associated with diffuse anasarca of the fetus (Figures A and B ). This anasarca is a fairly characteristic feature in the second trimester. In addition, there may be a focal form of cystic hygroma with a separate cystic mass in the cranial, neck, or thoracic region without hydrops. A focal cystic hygroma is associated with a good prognosis.

    Prognosis and Management
    The prognosis of fetal hydrops depends on the specific diagnosis. Fetal cystic hygroma is associated with an increased risk of other abnormalities, including Turner syndrome (XO karyotype) and pseudo-Turner syndrome (Noonan syndrome). Newborns with Turner syndrome have short stature, webbed neck, cardiac defects, and ovarian dysgenesis. In cases of fetal hydrops, it is important to perform a complete ultrasound examination. A basic approach for fetal hydrops could include amniocentesis for karyotyping and a comprehensive ultrasound examination to detect other abnormalities. If immediate diagnosis is needed, cordocentesis may be performed. Other therapy can be based on the precise etiology. If there is tachyarrhythmia, this may be identified by M-mode ultrasound, and treatment such as pharmacologic therapy can be initiated to convert the abnormal fetal heart rate to sinus rhythm.
    CASE 7


    History: A patient with a second-trimester pregnancy undergoes imaging because of an abnormally small increase in uterine enlargement on physical examination.

    1 . What should be included in the differential diagnosis for the main finding of the very small amount of amniotic fluid in the second-trimester fetus of the patient (Figures A and B ) and a different third-trimester fetus (Figure C )? (Choose all that apply.)
    A. Spontaneous rupture of the membranes (SROM)
    B. Gestation extending beyond the due date
    C. Potter syndrome
    D. Fetal demise
    2 . What quantitative measure is used to evaluate the severity of decreased amniotic fluid?
    A. Amniotic fluid index
    B. Resistive index
    C. Pulsatility index
    3 . What is the most likely cause of death of the newborn?
    A. Congestive heart failure
    B. Pulmonary hypoplasia
    C. Renal failure
    D. Growth restriction
    4 . What is the potentially serious short-term complication of membrane rupture?
    A. Hip dysplasia
    B. Congestive heart failure
    C. Clubfoot
    D. Chorioamnionitis

    ANSWERS

    CASE 7

    Oligohydramnios

    1 . A, C, and D
    2 . A
    3 . B
    4 . D

    References
    Cunningham FG, MacDonald PC, Gant NF, et al: Placental disorders: disease and abnormalities of the fetal membranes. In Cunningham FG, Williams JW, (eds): Williams Obstetrics , 20th ed. Stamford, CT, Appleton Lange 1997, pp 664-665.
    Kilbride HW, Yeast J, Thibeault DW: Defining limits of survival: lethal pulmonary hypoplasia after midtrimester premature rupture of membranes. Am J Obstet Gynecol . 1996; 175(3 Pt 1):675-681.
    http://www.ncbi.nlm.nih.gov/pubmed/8828433 (Accessed on May 30, 2012.).
    Ott WJ: Reevaluation of the relationship between amniotic fluid volume and perinatal outcome. Am J Obstet Gynecol 2005; 192(6):1803-1809.
    http://www.ncbi.nlm.nih.gov/pubmed/15970814 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 458, 460.

    Comment

    Ultrasound Imaging to Diagnose Oligohydramnios
    Second- and third-trimester fetuses are imaged because of a history of abnormally small increase in uterine enlargement on physical examination. Abnormalities in amniotic fluid volume reflect underlying fetal, maternal, and placental conditions. Oligohydramnios is a fluid volume less than the 5th percentile for a specific gestational age. The amniotic fluid volume peaks in the second trimester. Although the diagnosis can be made by measuring the fluid as four perpendicular measurements added together, a subjective evaluation of the amount of fluid is accurate.

    Ultrasound Imaging of Bilateral Renal Agenesis
    Severe oligohydramnios should prompt an ultrasound scan to identify the cause (Figures A to C ). The anatomy should be evaluated for the presence of kidneys (Figure B ) and fluid in the urinary bladder; in cases of bilateral renal agenesis, both kidneys and fluid are absent. As this case of bilateral renal agenesis shows, the abnormality in amniotic fluid volume may be immediately apparent (Figures A and B ). Fetal kidneys can be seen at 12 to 14 weeks gestation. The adrenal glands are large in utero and can resemble kidneys; the urinary bladder is still not present. Color Doppler imaging has been useful in documenting the presence of renal arteries. A severe bilateral renal obstruction or any other bilateral renal anomaly that affects function would also lead to severe oligohydramnios.

    Ultrasound Imaging of Spontaneous Rupture of Membranes
    A separate case of SROM in a third-trimester fetus (Figure C ) shows that the degree of oligohydramnios can be severe. Frequently the kidneys can be seen, and the urinary bladder can be identified. In cases of SROM in which the amniotic fluid index is less than 1 cm, the duration of this exposure to oligohydramnios and the gestational age at the time of membrane rupture are predictors of fetal outcome. Fetal mortality is greater than 90% if membranes rupture before 25 weeks and the exposure to severe oligohydramnios continues for more than 14 days. Chorioamnionitis is a serious complication. Lethal pulmonary hypoplasia occurs in 20% of cases of membrane rupture. In fetuses that survive severe oligohydramnios secondary to membrane rupture, limb deformities can occur. Of fetuses born after more than 2 weeks of this exposure, 80% had such deformities.

    Additional Causes of Oligohydramnios
    Alternative causes of oligohydramnios include growth restriction, chromosomal anomalies, congenital anomalies (e.g., cystic hygroma), and fetal demise. Maternal causes include hypertension, diabetes, and preeclampsia. Placental insufficiency, a cause of oligohydramnios later in gestation, warrants umbilical artery Doppler imaging whenever the fluid volume appears low. To exclude rupture of the membranes as the cause, the mother should be asked about fluid leakage.

    Postdates Gestation
    In gestations that extend beyond the expected due date, amniotic fluid can normally decrease. This decrease may result in umbilical cord compression and fetal heart deceleration. Monitoring includes frequent amniotic fluid index measurements and subjective quantitative measurements of fluid volume, maternal assessment of fetal movement, and fetal nonstress cardiac testing.
    CASE 8


    History: A 55-year-old, postmenopausal woman presents with a palpable right-sided pelvic mass.

    1 . What should be included in the differential diagnosis of this right-sided pelvic mass based on the ultrasound images (Figures C and D )? (Choose all that apply.)
    A. Ovarian cancer
    B. Cystadenoma
    C. Tuboovarian abscess
    D. Dermoid
    E. Dominant ovarian follicle
    2 . What is the most likely diagnosis?
    A. Ovarian cancer
    B. Cystadenoma
    C. Tuboovarian abscess
    D. Dermoid
    3 . What does the spectral waveform from the soft tissue component of the mass suggest?
    A. Benign process
    B. Concern for malignancy
    C. High resistance
    4 . Which benign ovarian masses do not show high diastolic flow?
    A. Tuboovarian abscess
    B. Endometriomas
    C. Dermoids
    D. Simple ovarian cysts

    ANSWERS

    CASE 8

    Ovarian Cancer

    1 . A, B, C, and D
    2 . A
    3 . B
    4 . D

    References
    Alcazar JL, Galan MJ, Ceamanos C, et al: Transvaginal gray scale and color Doppler sonography in primary ovarian cancer and metastatic tumors to the ovary. J Ultrasound Med . 2003; 22(3):243-247.
    http://www.ncbi.nlm.nih.gov/pubmed/12636323 (Accessed on May 30, 2012.).
    Alcazar JL, Galal MJ, Garcia-Manero M, et al: Three-dimensional sonographic morphologic assessment in complex adnexal masses. J UltrasoundMed . 2003; 22(3):249-254.
    http://www.ncbi.nlm.nih.gov/pubmed/12636324 (Accessed on May 30, 2012.).
    Brown DL, Zou KH, Tempany CM, et al: Primary versus secondary ovarian malignancy: imaging findings of adnexal masses in the Radiology Diagnostic Oncology Study. Radiology 2001; 219(1):213-218.
    http://www.ncbi.nlm.nih.gov/pubmed/11274559 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 579-583.

    Comment

    Gray-Scale Ultrasound Features of Ovarian Cancer
    Ovarian cancer exhibits numerous ultrasound criteria for a malignant mass (Figures A and B ). The presence of a solid component or solid papillary mural projections (Figure A ), particularly if they are nonhyperechoic, is worrisome. A hyperechoic solid component is seen more typically in a dermoid. If a fluid component is present, it is more commonly anechoic or hypoechoic. Septations may or may not occur in a malignant mass, but if present, they are usually 3 mm or thicker. The wall is often not discernible but can be thin or thick if seen. A malignant cyst is accompanied by ascites in 30% of cases, which suggests spread to the pelvis (stage 2) or abdomen (stage 3 or 4). Multilocularity favors the diagnosis of a primary ovarian neoplasm rather than a secondary one. A purely solid tumor indicates a higher probability of metastatic carcinoma rather than primary ovarian carcinoma (Figure C ).

    Doppler Ultrasound Features of Ovarian Cancer
    Use of Doppler ultrasound to distinguish a benign from a malignant ovarian mass has been shown to be nonpredictive. Doppler ultrasound has been applied on the principle that low impedance flow should indicate a malignancy. When arterial signals are detected, the systolic and diastolic components can be evaluated. Measurements include the resistive index, or RI: (peak systolic velocity - end diastolic velocity) peak systolic velocity, and the pulsatility index, or PI: (peak systolic velocity - end diastolic velocity) mean velocity. The standard cutoff level for malignancy is RI less than 0.4 or PI less than 1.0. It is common for a malignant lesion to have a borderline or low ratio that is suggestive of a malignancy (Figure D ). Conversely, arterial flow with systolic flow but little or no diastolic flow is a high-resistance signal that is seen almost exclusively in benign lesions.

    Magnetic Resonance Imaging of Ovarian Masses
    Considerable overlap has been shown between benign and malignant masses when the spectral waveform shows an arterial waveform with a high diastolic component (low impedance). In the case presented here, RI is borderline, and the mass was pathologically malignant. Benign masses that are endocrine secreting or inflammatory may have this flow pattern, particularly tuboovarian abscesses, endometriomas, and ovarian dermoids. In a more recent large study, in women with an indeterminate mass on gray-scale ultrasound, the use of MRI contributed more to a change in probability of malignancy in both premenopausal and postmenopausal women than did the use of CT or combined gray-scale and Doppler ultrasound.
    CASE 9


    History: A 40-year-old woman with a late first-trimester pregnancy presents with right lower quadrant pain.

    1 . What should be included in the differential diagnosis of the transabdominal images (Figures A to C )? (Choose all that apply.)
    A. Meckel diverticulum
    B. Acute appendicitis
    C. Crohn disease
    D. Intussusception
    2 . Which finding suggests appendicitis but is also seen normally in the pregnancy state?
    A. Anemia
    B. Leukocytosis
    C. Left lower quadrant pain
    D. Thrombocytopenia
    3 . Which of the following findings is not a complication of acute appendicitis?
    A. Large-for-dates fetus
    B. Preterm delivery
    C. Spontaneous abortion
    D. Internal fetal sepsis
    E. Neonatal neurologic injury
    4 . What is the worst complication of appendicitis in a third-trimester gestation?
    A. Anemia
    B. Peritonitis
    C. Adhesions

    ANSWERS

    CASE 9

    Acute Appendicitis

    1 . A and B
    2 . B
    3 . A
    4 . B

    References
    Glanc P, Maxwell C: Acute abdomen in pregnancy: role of sonography. J Ultrasound Med 2010; 29(10):1457-1468.
    http://www.ncbi.nlm.nih.gov/pubmed/20876900 (Accessed on May 30, 2012.).
    Long SS, Long C, Macura KJ: Imaging strategies for right lower quadrant pain in pregnancy. AJR Am J Roentgenol 2011; 10(1):4-12.
    http://www.ncbi.nlm.nih.gov/pubmed/21178041 (Accessed on May 30, 2012.).
    McGahan JP, Lamba R, Coakley FV: Imaging non-obstetrical causes of abdominal pain in the pregnant patient. Appl Radiol 2010; :10-25.
    http://www.appliedradiology.com/Article.aspx?id=25245 (Accessed on June 25, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 224-225.

    Comment

    Clinical Findings
    Appendicitis occurs in 1 in 1500 pregnant women. It is the most common cause of nontraumatic abdominal pain in pregnancy. It can develop in the first, second, or third trimester. The symptoms of appendicitis are identical to symptoms that occur in a normal pregnancy. Leukocytosis and nausea are common. The enlarging uterus can cause severe right lower quadrant pain owing to round ligament strain. The clinical differential diagnosis of right lower quadrant pain in pregnancy includes appendicitis, renal calculus, pyelonephritis, placental abruption, degeneration of myoma, ovarian cyst, and torsion. Right lower quadrant pain has been found to be the most common presenting symptom of appendicitis in pregnancy regardless of gestational age. The location of the cecum and the appendix may be distorted during pregnancy. Fever and leukocytosis are not clear indicators of appendicitis in pregnancy.

    Ultrasound Findings
    Ultrasound with graded compression has been used to make the diagnosis, avoiding the ionizing radiation of CT. Early in pregnancy, the inflamed appendix may be visualized as a noncompressible tubular structure measuring 7 mm or more, as shown in this case (Figures A to C ), with a diameter of 15 mm. An appendicolith may be present (Figure B ). Doppler ultrasound has been found to be a sensitive indicator of inflammation and increased diastolic flow with a low resistive index (see hyperemia in Figure C ). Pain often occurs directly over this area. In the setting of perforation, a collection of peritoneal fluid may be detected. As the uterus enlarges, the appendix can move superiorly and toward the flanks. Acute appendicitis is more difficult to diagnosis in the third trimester.

    Magnetic Resonance Imaging
    MRI is a safe modality to evaluate pregnant patients if there is a clinical suspicion of acute appendicitis. Unnecessary operations can be avoided when a normal appendix is imaged. In one series, 50% of pregnant women who underwent surgery had appendicitis.

    Complications of Appendicitis
    If the diagnosis of appendicitis is missed, peritonitis results. In the third trimester, peritonitis has a poor prognosis, and maternal mortality is approximately 5%. Other complications include preterm labor, spontaneous abortion, and fetal neurologic injury if maternal-fetal sepsis results.
    CASE 10


    Used with permission from McGahan JP, et al: Fetal abdomen and pelvis. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1316. Courtesy of Marshal Swartz, MD.


    Used with permission from McGahan JP, et al: Fetal abdomen and pelvis. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1316.


    History: A patient from an outside institution presents with an ultrasound scan showing a fetal mass and undergoes a second ultrasound examination.

    1 . What should be included in the differential diagnosis of Figure A ? (Choose all that apply.)
    A. Sacral meningomyelocele
    B. Limb-body wall complex
    C. Omphalocele
    D. Amniotic band syndrome
    E. Sacrococcygeal teratoma
    2 . Which of the following statements concerning sacrococcygeal teratoma is not true?
    A. Incidence is approximately 1:40,000.
    B. Most prenatally detected sacrococcygeal teratomas are malignant.
    C. Sacrococcygeal teratomas are associated with a female-to-male ratio of approximately 4:1.
    D. Few sacrococcygeal teratomas are entirely internal within the sacrum.
    3 . Which of the following statements concerning the ultrasound appearance of sacrococcygeal teratoma is not true?
    A. Fetal MRI may be helpful to detect the internal presacral components of sacrococcygeal teratoma.
    B. Sacrococcygeal teratomas are often associated with an abnormal karyotype.
    C. Color Doppler ultrasound may show a highly vascular mass with large solid teratomas.
    D. These tumors may be cystic, solid, or mixed.
    4 . Which of the following is not a poor prognostic factor associated with sacrococcygeal teratomas?
    A. Development of fetal hydrops
    B. Malignant histology of the lesion
    C. Presence of external rather than internal sacral components
    D. Size of the tumor

    ANSWERS

    CASE 10

    Sacrococcygeal Teratoma

    1 . A, B, D, and E
    2 . B
    3 . B
    4 . C

    References
    Gucciardo L, Uyttebroek A, De Wever I, et al: Prenatal assessment and management of sacrococcygeal teratoma. Prenat Diagn 2011; 31(7):678-688.
    http://www.ncbi.nlm.nih.gov/pubmed/21656530 (Accessed on May 30, 2012.).
    Ho KO, Soundappan SV, Walker K, et al: Sacrococcygeal teratoma: the 13-year experience of a tertiary paediatric centre. J Paediatr Child Health 2011; 47(5):287-291.
    http://www.ncbi.nlm.nih.gov/pubmed/21599781 (Accessed on May 30, 2012.).
    Wilson RD, Hedrick H, Flake AW, et al: Sacrococcygeal teratomas: prenatal surveillance, growth and pregnancy outcome. Fetal Diagn Ther 2009; 25(1):15-20.
    http://www.ncbi.nlm.nih.gov/pubmed/19122459 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 408-410.

    Comment

    Differential Diagnosis
    The differential diagnosis of a presacral mass is straightforward. Sacrococcygeal teratomas may be cystic or solid or mixed. They may be quite large. The differential diagnosis is small because sacrococcygeal teratomas have a pathognomonic appearance. However, myelomeningocele can be considered within the differential diagnosis. A less likely consideration would be amniotic bands leading to amputational defects whether within the pelvis or elsewhere within the fetus. Likewise, there is a spectrum of abnormalities that can occur with limb-body wall complex. In this anomaly, the fetus fuses with the placenta and other amputational defects occur in the fetus. When a meningomyelocele is present, the fetus usually has a lemon-shaped head and a banana-shaped cerebellum, which is helpful for ultrasound findings associated with meningomyelocele.

    Ultrasound Findings
    On ultrasound, a sacrococcygeal teratoma appears as a cystic, solid, or mixed cystic and solid mass arising from the sacrococcygeal region (Figures A to D ). Teratomas are tumors consisting of tissues from all three germ layers-ectoderm, mesoderm, and endoderm. They are thought to have originated from totipotent cells of the Hensen node. Sacrococcygeal teratomas are located midline in the presacral region and are uniformly attached to the coccyx. Several patterns may be shown with sacrococcygeal teratomas, including predominantly a solid mass with small anechoic regions as identified in this case (Figures A and B ), a unilocular cystic mass (Figures C and D ), or a mixed cystic and solid mass.
    Four types of sacrococcygeal teratomas have been described:

    Type I-predominantly external with minimal presacral component
    Type II-predominantly external with significant intrapelvic component
    Type III-predominantly internal with abdominal extension
    Type IV-entirely internal with no external component
    Types I and II account for most cases. Only 10% of sacrococcygeal teratomas are type IV. Type IV sacrococcygeal teratomas have a higher rate of malignancy. MRI may be helpful to define better the extent of the sacrococcygeal teratoma, especially internal (presacral) components (Figures C and D ). Depending on the size and vascularity of the teratoma, polyhydramnios and fetal hydrops may result, both of which are poor prognostic indicators.

    Prognosis and Management
    The prognosis depends on the development of fetal hydrops, malignant versus benign histology, and the size of the tumor. Hydrops occurs typically with a larger solid tumor, which has a significant vascular component that can result in hydrops and fetal demise. There is a lower risk of malignancy in type I and type II sacrococcygeal teratomas, whereas type IV teratomas have a higher rate of malignancy and are associated with a poor prognosis. Fetal hydrops results from high-output cardiac failure, similar to what is observed in arteriovenous malformations such as vein of Galen aneurysm or chorioangiomas. These conditions are referred to as a vascular steal phenomenon. Emergency therapy such as delivery by cesarean section may be indicated when there is increase in tumor growth, signs of cardiac failure, or hydrops. If none of these factors is present, the fetus may be monitored weekly with either planned vaginal or cesarean delivery depending on the size of the tumor. Rare fetal interventions include major vessel ablation, amniodrainage to prevent preterm labor, and cyst decompression before delivery. In rare instances, such as in the presence of early fetal hydrops, in utero resection has been performed. Even with successful surgery, there may be resultant injury to the bowel or bladder after birth.
    CASE 11


    Used with permission from McGahan JP, et al: Fetal head and brain. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1151.


    Used with permission from McGahan JP, et al: Fetal head and brain. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1151.
    History: Three separate cases of ultrasound through the fetal head between 20 and 22 weeks gestation are presented.

    1 . What should be included in the differential diagnosis? (Choose all that apply.)
    A. Arachnoid cyst
    B. Dandy-Walker malformation
    C. Dandy-Walker variant
    D. Mega cisterna magna
    E. Hydrocephalus
    2 . Concerning Dandy-Walker syndrome, which of the following statements is not true?
    A. This syndrome includes cystic dilation in the fourth ventricle.
    B. There is complete or partial agenesis of the cerebellar vermis.
    C. It is rarely associated with other structural abnormalities.
    D. It is often associated with karyotypic abnormalities.
    3 . Which of the following entities is not an abnormality related to Dandy-Walker complex?
    A. Dandy-Walker malformation
    B. Dandy-Walker variant
    C. Arachnoid cyst
    D. Mega cisterna magna
    4 . Which of the following statements is true?
    A. There are rarely karyotypic abnormalities with Dandy-Walker variant.
    B. Dandy-Walker syndrome has a higher association of neonatal death than Dandy-Walker variant.
    C. Ventriculomegaly is an uncommon finding with Dandy-Walker malformation.
    D. Dandy-Walker variant is commonly associated with fetal anatomic defects.

    ANSWERS

    CASE 11

    Dandy-Walker Complex

    1 . A, B, and C
    2 . C
    3 . C
    4 . B

    References
    Bromley B, Nadel AS, Pauker S, et al: Closure of the cerebellar vermis: evaluation with second trimester US. Radiology 1994; 193(3):761-763.
    http://www.ncbi.nlm.nih.gov/pubmed/7972820 (Accessed on May 30, 2012.).
    Ecker JL, Shipp TD, Bromley B, et al: The sonographic diagnosis of Dandy-Walker and Dandy-Walker variant: associated findings and outcomes. Prenat Diagn 2000; 20(4):328-332.
    http://www.ncbi.nlm.nih.gov/pubmed/10740206 (Accessed on May 30, 2012.).
    Shekdar K: Posterior fossa malformations. Semin Ultrasound CT MR 2011; 32(3):228-241.
    http://www.ncbi.nlm.nih.gov/pubmed/21596278 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 390-395.

    Comment

    Differential Diagnosis
    The differential diagnosis for a midline cystic abnormality in the posterior fossa would include classic Dandy-Walker malformation, Dandy-Walker variant, and perhaps a posterior fossa arachnoid cyst. Mega cisterna magna, in which there is an enlarged cisterna magna but with integrity of the cerebellar vermis and the fourth ventricle, would be less likely to be included in the differential diagnosis.

    Ultrasound Findings
    Dandy-Walker complex refers to the spectrum of anomalies of the posterior fossa (Figures A to C ). Ultrasound findings of Dandy-Walker complex can include classic Dandy-Walker malformation, characterized by cystic dilation in the fourth ventricle, partial or complete agenesis of the cerebellar vermis, and an enlarged posterior fossa with displacement of the tentorium superiorly. The cyst communicates with the fourth ventricle through the defect in the cerebellar vermis (Figures A and B ). This was originally termed Dandy-Walker syndrome.
    In the less severe form of Dandy-Walker complex called Dandy-Walker variant (Figure C ), there is variable hypoplasia of the cerebellar vermis with or without enlargement of the posterior fossa. It would seem that this variant would carry a much better prognosis than classic Dandy-Walker malformation; however, ultrasound abnormalities, including ventriculomegaly, cardiac defects, and karyotypic abnormalities, are common. The prognosis of Dandy-Walker variant is slightly better than the prognosis of Dandy-Walker malformation; normal outcomes have been reported in infants with isolated findings of Dandy-Walker variant. Care must be taken not to suggest the diagnosis of Dandy-Walker variant too early. The cerebellar vermis does not close from superior to inferior until 17 to 18 weeks gestation. At 15 to 16 weeks, it is common to find the cerebellar vermis not completely closed. One must be careful not to overcall Dandy-Walker variant at this stage of pregnancy because there may still be communication with the fourth ventricle and the posterior fossa.

    Prognosis and Management
    Prognosis and management depend on associated abnormalities and karyotypic findings. In one series, 85% of fetuses with Dandy-Walker malformation or Dandy-Walker variant had other abnormalities identifiable on ultrasound. In addition, approximately one third of cases of Dandy-Walker malformation or Dandy-Walker variant have an abnormal karyotype. However, in Dandy-Walker variant, there is a higher rate of neonatal survival and otherwise normal infants compared with Dandy-Walker malformation. Overall, the presence of other abnormalities is associated with the worst prognosis. An isolated Dandy-Walker variant has the highest chance of leading to a normal neonate.
    CASE 12


    Used with permission from McGahan JP, et al: Fetal head and brain. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1156.


    Used with permission from McGahan JP, et al: Fetal head and brain. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1156.


    Used with permission from McGahan JP, et al: Fetal head and brain. In McGahan JP, Goldberg BB [eds]: Diagnostic Ultrasound, 2nd ed. New York: Informa Healthcare USA, 2008; 1156.
    History: A pregnant patient presents with a suspected cystic fetal brain abnormality.

    1 . What should be included in the differential diagnosis for a midline cystic abnormality in the fetal brain? (Choose all that apply.)
    A. Choroid plexus cyst
    B. Porencephaly
    C. Schizencephaly
    D. Arachnoid cyst
    E. Vein of Galen aneurysm
    2 . Which of the following entities is not an abnormality that may be identified within the brain of the fetus or newborn in cases of arteriovenous malformations (AVMs)?
    A. Ventriculomegaly
    B. Porencephaly
    C. Brain edema
    D. Occlusion of the internal carotid artery
    3 . Which of the following conditions is not associated with brain AVMs?
    A. Fetal hydrops
    B. Cardiomegaly
    C. Arachnoid cyst
    D. Pleural effusion
    4 . Which of the following options would not be considered in management of fetal cerebral AVM?
    A. Performing serial scans
    B. In utero embolization of fetal AVM
    C. Early delivery with development of fetal hydrops
    D. Ruling out vaginal delivery

    ANSWERS

    CASE 12

    Central Nervous System Arteriovenous Malformation

    1 . D and E
    2 . D
    3 . C
    4 . B

    References
    Lee TH, Shih JC, Peng SS, et al: Prenatal depiction of angioarchitecture of an aneurysm of the vein of Galen with three-dimensional color power angiography. Ultrasound Obstet Gynecol 2000; 15(4):337-340.
    http://www.ncbi.nlm.nih.gov/pubmed/10895457 (Accessed on May 30, 2012.).
    Li AH, Armstrong D, terBrugge KG: Endovascular treatment of vein of Galen aneurysmal malformation: management strategy and 21-year experience in Toronto. J Neurosurg Pediatr 2011; 7(1):3-10.
    http://www.ncbi.nlm.nih.gov/pubmed/21194279 (Accessed on May 30, 2012.).
    Kurihara N, Tokieda K, Ikeda K, et al: Prenatal MR findings in a case of aneurysm of the vein of Galen. Pediatr Radiol 2001; 31(3):160-162.
    http://www.ncbi.nlm.nih.gov/pubmed/11297077 (Accessed on May 30, 2012.).

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 381, 391, 393, 398.

    Comment

    Differential Diagnosis
    The differential diagnosis for a midline intracranial cyst includes an arachnoid cyst. This is a smooth-walled cyst located anywhere within the brain and may have associated mass effect. Agenesis of the corpus callosum with an interhemispheric cyst could be considered. These cysts lie between the frontal horns of the lateral ventricle and are usually midline. Cystic neoplasm may be considered in the differential diagnosis, but these neoplasms usually have solid components and are asymmetric. They are very rare in utero. Finally, vein of Galen aneurysms or fetal cerebral AVMs are the most likely differential diagnoses in this case after power Doppler is used.

    Ultrasound Findings
    Three different types of congenital cerebral aneurysms have been described: arteriovenous fistula, AVM with ectasia of the vein of Galen, and varix of the vein of Galen. Arteriovenous fistula may be seen in the fetus and manifests in the neonatal period with cardiac failure. All of these anomalies may be identified as an elongated anechoic area at the level of the cistern of the vein of Galen (Figure A ). With color and pulsed Doppler imaging, there is evidence of turbulent venous and arterial flow (Figure B ). Occasionally, the vascular malformation may show increased echogenicity if a clot has formed within it. Cerebral architecture is usually intact, but ventriculomegaly and porencephaly may develop if there is associated infarction. Signs of fetal hydrops from cardiac overload may be present, including cardiomegaly, soft tissue edema, and polyhydramnios, which eventually lead to overt hydrops. MRI may be useful to identify the anomaly in utero (Figure C ).

    Prognosis and Management
    Serial in utero scans are used to monitor the cardiovascular condition of the fetus and identify early signs of fetal hydrops. Delivery may be planned depending on fetal lung maturation and development of early hydrops. After delivery, management includes various endovascular techniques, such as different embolization agents and different novel approaches.
    CASE 13


    History: Ultrasound is performed on an asymptomatic woman with a late second-trimester pregnancy.

    1 . What is the diagnosis in the cervical region?
    A. Circumvallate placenta
    B. Succenturiate lobe
    C. Placental abruption
    D. Placenta previa
    2 . Which of the two images (Figures A and B ) is a better performed image for the diagnosis and why?
    A. Figure B , in which the maternal bladder is empty
    B. Figure A , in which the maternal bladder is full
    C. Figure A for the image of the cervix
    D. Figure B for the image of the cervix
    3 . Which type of ultrasound study is known to be a problem in making this diagnosis?
    A. Transabdominal with a full bladder
    B. Transabdominal with an empty bladder
    C. Translabial with an empty bladder
    D. Transvaginal with an empty bladder
    4 . Which of the following is not a complication of placenta previa?
    A. Hemorrhage
    B. Placenta accreta
    C. Intrauterine growth restriction
    D. Macrosomia

    ANSWERS

    CASE 13

    Placenta Previa

    1 . D
    2 . A
    3 . A
    4 . D

    References
    Mabie WC: Placenta previa. Clin Perinatol 1992; 19(2):425-435.
    http://www.ncbi.nlm.nih.gov/pubmed/1617885 (Accessed on May 20, 2012.)
    Predanic M, Perni SC, Baergen RN, et al: A sonographic assessment of different patterns of placenta previa migration in the third trimester of pregnancy. J Ultrasound Med 2005; 24(6):773-780.
    http://www.ncbi.nlm.nih.gov/pubmed/15914681 (Accessed on May 20, 2012.)
    Wu S, Kocherginsky M, Hibbard JU: Abnormal placentation: twenty-year analysis. Am J Obstet Gynecol 2005; 192(5):1458-1461.
    http://www.ncbi.nlm.nih.gov/pubmed/15902137 (Accessed on May 20, 2012.)

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 488, 498-504.

    Comment

    Types of Placenta Previa
    Implantation of the placenta over the cervix (Figures A and B ) is known as placenta previa. Placenta previa can be complete (the internal os is covered by placenta), partial (partial coverage of the os), or marginal (the placental edge is at the margin of the os). A low-lying placenta (within 2 cm of the internal os) does not reach the internal os but may be clinically important because it can be incorporated into the dilated cervix at the time of delivery, leading to hemorrhage. Placenta previa complicates about 0.4% of all third-trimester pregnancies. Risk factors include prior cesarean delivery, history of placenta previa in a previous pregnancy, increasing parity, advanced maternal age, prior uterine surgery, tobacco use, and multiple gestations.

    Ultrasound Imaging of the Placenta
    Many cases can be diagnosed with transabdominal ultrasound. The bladder must be empty to make an accurate diagnosis. A distended maternal bladder (Figure A ) or uterine contraction can cause a false-positive result by compressing the lower uterine segment and making a low-lying placenta appear as a placenta previa. Translabial and transvaginal imaging after bladder emptying is often necessary to visualize the lower uterine segment adequately, particularly in the third trimester. The transvaginal probe should be inserted only partially to avoid direct contact with the cervix. When complete placenta previa is diagnosed at second-trimester screening sonography, it is less likely to resolve in patients with previous cesarean delivery.

    Complications of Placenta Previa
    Other complications can occur in addition to hemorrhage. An anterior placenta may invade the uterine wall (placenta accreta), particularly in patients with a placenta previa, advanced maternal age, and a history of cesarean section. Fetal complications include intrauterine growth restriction and subsequent development of cerebral palsy. A low-lying placenta may increase the incidence of small-for-gestational-age fetuses.

    Prognosis of Placenta Previa
    Most cases diagnosed early in pregnancy resolve, probably because of placental remodeling owing to poor blood supply of the lower uterine segment. Follow-up imaging is required in the third trimester (at approximately 30 weeks). A cesarean section is performed for persistent placenta previa. A final placental distance of less than 2 cm from the internal os and a deceleration pattern of placental migration have been significantly associated with the need for a cesarean delivery.
    CASE 14


    History: An asymptomatic patient with a second-trimester pregnancy undergoes ultrasound.

    1 . What is the diagnosis for this fetus?
    A. Hydrocephalus
    B. Alobar holoprosencephaly
    C. Anencephaly
    D. Strawberry skull
    2 . When can this disorder be reliably diagnosed on ultrasound?
    A. In the beginning of the third trimester
    B. In the middle of the first trimester
    C. In the second trimester
    D. Never
    3 . When in gestation does the neural tube close?
    A. At the end of the first trimester
    B. At 24 days of fetal life
    C. At the beginning of the third trimester
    D. At 10 days of fetal life
    4 . Which maternal dietary deficiency is associated with this disorder?
    A. Folic acid
    B. Iron
    C. Copper
    D. Thiamine

    ANSWERS

    CASE 14

    Anencephaly

    1 . C
    2 . C
    3 . B
    4 . A

    Reference
    Goldstein RB, Filly RA: Prenatal diagnosis of anencephaly: spectrum of sonographic appearances and distinction from the amniotic band syndrome. AJR Am J Roentgenol 1988; 151(3):547-550.
    http://www.ncbi.nlm.nih.gov/pubmed/3044042 (Accessed on May 30, 2012.)

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 374-376.

    Comment

    Common Neural Tube Defect
    With an overall frequency of 1 in 1000, anencephaly is one of the most common neural tube defects. The incidence varies in different parts of the world. The cerebral cortex and skull are absent; orbits, brainstem, and skull base are present. In some cases, angiomatous stroma, or vascular, dysmorphic tissue, may cover the brainstem. As in other central nervous system anomalies, polyhydramnios is also often present, particularly later in the gestation period. Anencephaly is incompatible with life. A deficiency of maternal folic acid has been shown to increase the risk of neural tube defects. It is recommended that women begin folic acid supplementation before becoming pregnant to decrease the risk of anencephaly and other neural tube defects.

    Ultrasound Imaging of Anencephaly
    Ultrasound shows the absence of a calvaria and brain above the orbits (Figures A and B ), cephalad to the brainstem. Although this may be detected by 8 weeks gestation, it is diagnosed more reliably in the early second trimester.

    Serum Alpha-Fetoprotein and Anencephaly
    Routine screening of maternal serum alpha-fetoprotein (AFP) is performed between 15 and 20 weeks gestation as part of the serum triple screen (AFP, estriol, and human chorionic gonadotropin). Serum AFP is usually elevated in anencephaly, using either 2 or 2.5 multiples of median gestational age as the cutoff for detection. It is important that the pregnancy be dated accurately because the levels vary with gestational age. The serum AFP level also is abnormal in multiple gestations and obese women. The differential diagnosis for an elevated maternal AFP in pregnancy includes other open defects, such as gastroschisis, and fetomaternal hemorrhage, maternal hepatitis, and maternal hepatocellular carcinoma.
    CASE 15


    Used with permission from Anderson Publishing Ltd., from Victoria T, et al: Fetal MRI of common non-CNS abnormalities: a review. Appl Radiol 40[6]8-17, 2011. Anderson Publishing Ltd.
    History: Axial scans through the upper abdomen in two separate fetuses with the same abnormalities are shown.

    1 . What should be included in the differential diagnosis of Figure A and Figure B ? (Choose all that apply.)
    A. Choledochal cyst
    B. Duplication cyst
    C. Ovarian cyst
    D. Duodenal atresia
    E. Renal cyst
    2 . The differential diagnosis of the double bubble sign of a dilated stomach and dilated duodenum would include all of the following except:
    A. Malrotation with midgut volvulus
    B. Annular pancreas
    C. Duodenal atresia
    D. Hepatic cyst
    3 . Which of the following statements concerning duodenal atresia is false?
    A. Approximately 40% of fetuses with trisomy 21 have duodenal atresia.
    B. The presence of duodenal atresia and an endocardial cushion defect is a very strong indicator of trisomy 21.
    C. There is an increased risk of other intestinal atresia with duodenal atresia.
    D. There is increased incidence of associated skeletal deformities with duodenal atresia.
    4 . All of the following are true statements concerning duodenal atresia except:
    A. Diagnosis is usually not evident until after 20 weeks gestation.
    B. Polyhydramnios is a typical finding of duodenal atresia.
    C. Concurrent cardiac anomalies, especially coarctation of the aorta, occurring with duodenal atresia are a strong indicator of trisomy 21.
    D. Overall mortality of duodenal atresia is greater than 20%.

    ANSWERS

    CASE 15

    Duodenal Atresia

    1 . B, C, and D
    2 . D
    3 . A
    4 . C

    References
    Choudhry MS, Rahman N, Boyd P, et al: Duodenal atresia: associated anomalies, prenatal diagnosis and outcome. Pediatr Surg Int 2009; 25(8):727-730.
    http://www.ncbi.nlm.nih.gov/pubmed/19551391 (Accessed on May 30, 2012.)
    Dankovcik R, Jirasek JE, Kucera E, et al: Prenatal diagnosis of annular pancreas: reliability of the double bubble sign with periduodenal hyperechogenic band. Fetal Diagn Ther 2008; 24(4):483-490.
    http://www.ncbi.nlm.nih.gov/pubmed/19047797 (Accessed on May 30, 2012.)
    Nyberg DA, Neilsen IR: Abdomen and gastrointestinal tract. In Nyberg DA, McGahan JP, Pretorius DH, et al (eds): Diagnostic Imaging of Fetal Anomalies . Philadelphia: Lippincott Williams Wilkins, 2003, pp 547-602.

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 436-437.

    Comment

    Differential Diagnosis
    This case presents two differential diagnoses. The first differential diagnosis includes a cystic mass in the upper abdomen such as gastric duplication cyst, choledochal cyst, hepatic cyst, or ovarian cyst. Other cystic masses could also be considered in the differential diagnosis. A second differential diagnostic consideration is the double bubble sign, which usually is associated with duodenal atresia but can include any intrinsic abnormalities of the duodenum causing obstruction, such as duodenal stenosis, a duodenal web, and intestinal malrotation or extrinsic compression on the duodenum (which would be rare).

    Ultrasound Findings
    The ultrasound findings of duodenal atresia include a double bubble sign, a classic sign of a fluid-filled dilated stomach on the left side of the abdomen accounting for one bubble and the second portion of the bubble corresponding to the dilated duodenal bulb to the right of midline. This sign is well delineated in this case (Figures A and B ). Polyhydramnios may develop in these cases but usually not until the third trimester. A double bubble sign is usually not detected until later in the second trimester, often not until 24 weeks, and may be seen with prenatal MRI (Figure C ). Ultrasound should show the connection between the dilated stomach and the dilated duodenum.

    Prognosis and Management
    Management depends on associated findings of duodenal atresia. Careful examination of the fetus should concentrate on identifying other malformations, including skeletal, gastrointestinal, cardiovascular, and genitourinary malformations. As mentioned before, many different skeletal malformations are associated with duodenal atresia, including vertebral and rib abnormalities. Other types of atresia associated with duodenal atresia include esophageal and small bowel atresia and rectal atresia or imperforate anus. Biliary atresia and pancreatic ductal atresia are associated with duodenal atresia. It is probably most important to check for endocardial cushion defects in these fetuses. If an endocardial cushion defect is present with duodenal atresia, it is almost pathognomonic of trisomy 21. There is a high incidence of trisomy 21 in fetuses with duodenal atresia. Amniocentesis is the accepted method of prenatal chromosomal analysis. Duodenal atresia by itself has a more favorable prognosis than duodenal atresia associated with other malformations. Mortality in most cases of duodenal atresia is associated with other malformations, such as cardiac anomalies. Because of significant fluid and electrolyte imbalance, the atretic segment should be bypassed after birth.
    CASE 16


    History: A patient has a routine ultrasound scan in the second trimester that shows a nuchal thickness of 7 mm at 20 weeks.

    1 . What should be included in the differential diagnosis of nuchal thickness of 7 mm at a gestational age of 20 weeks? (Choose all that apply.)
    A. Trisomy 21
    B. 45X (Turner syndrome)
    C. Triploidy karyotype
    D. Trisomy 13
    E. Trisomy 18
    2 . The most correct diagnosis for nuchal thickness in the second trimester would include a plane through all of the following except:
    A. Cavum septi pellucidi
    B. Cerebellar hemisphere
    C. Body of the lateral ventricle
    D. Cerebral peduncles
    3 . Which of the following statements concerning the measurement of nuchal thickness is false?
    A. Nuchal thickening is a sensitive nonstructural abnormality associated with trisomy 21.
    B. Redundant skin at the back of the neck associated with trisomy 21 was first reported by Benacerraf.
    C. A threshold of 6 mm or more is the measurement that has been reported for increased risk of trisomy 21.
    D. Cut-off of 5 mm or more of nuchal thickness may be a better threshold measurement for detection of Down syndrome.
    4 . Which of the following is not a subtle marker in Down syndrome (trisomy 21)?
    A. Absent nasal bone
    B. Shortened limbs
    C. Choroid plexus cysts
    D. Sandal gap toes

    ANSWERS

    CASE 16

    Nuchal Thickness in the Second Trimester

    1 . A, B, C, D, and E
    2 . C
    3 . B
    4 . C

    References
    Benacerraf BR, Gelman R, Frigoletto FD Jr: Sonographic identification of second-trimester fetuses with Down s syndrome. N Engl J Med 1987; 317(22):1371-1376.
    http://www.ncbi.nlm.nih.gov/pubmed/2960895 (Accessed on May 30, 2012.)
    Down JL: Observations on an ethnic classification of idiots. 1866. Ment Retard 1995; 33(1):54-56.
    http://www.ncbi.nlm.nih.gov/pubmed/7707939 (Accessed on May 30, 2012.)
    Nyberg DA, Souter VL, El-Bastawissi A, et al: Isolated sonographic markers for detection of fetal Down syndrome in the second trimester of pregnancy. J Ultrasound Med 2001; 20(10):1053-1063.
    http://www.ncbi.nlm.nih.gov/pubmed/11587012 (Accessed on May 30, 2012.)

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 394-395, 473.

    Comment

    Differential Diagnosis
    The differential diagnosis for increased nuchal thickening includes any of the trisomies and many other chromosomal abnormalities. Nuchal thickening is one of the most sensitive and important markers in detection of fetuses with trisomy 21 during the second trimester. Isolated nuchal thickening is associated with risk of other malformations, chromosomal abnormalities, and syndromes, but it is associated with a normal outcome in most fetuses.

    Ultrasound Findings
    The axial scan through the region of thalami and including the cavum septi pellucidi, the cerebral peduncles, and the cerebellar hemisphere is the plane used for measurement of nuchal thickness (see Figure ). Nuchal thickness is usually measured in the second trimester and was originally suggested to be a measurement after 15 weeks gestation by Benacerraf et al. This measurement is determined from the outer portion of the bony calvaria to the outer portion of the posterior scalp. Although 6 mm was used for the original measurement, some authors believe 5 mm is a better threshold. Lowering the threshold measurement to 5 mm improves the sensitivity at the expense of decreased specificity; this could lead to increased detection of trisomy 21 but at the expense of unnecessary alarm to the parents, with an increased risk for additional amniocentesis.

    Prognosis and Management
    A nuchal thickness of 6 mm was the original measurement used for detection of Down syndrome by Benacerraf et al. Isolated increased nuchal thickening would increase the risk for Down syndrome, which would be weighted against serum screening, maternal age, and detection of other subtle ultrasound markers. Evaluation of the fetus should include not only measurement of the nuchal thickness but also checking for any cardiac defects and other subtle ultrasound markers, including renal pyelectasis greater than 4 mm, echogenic bowel, echogenic cardiac focus, short femur, short humerus, and ventriculomegaly. All of these results can be used in combination with either a triple marker screen or a quad marker screen. A quad marker screen would include a maternal blood sample to check for the following substances: alpha-fetoprotein, unconjugated estradiol, human chorionic gonadotropin, and inhibin A. Using all of these values and maternal age, a risk assessment for potential chromosomal abnormalities such as trisomy 21 can be made.
    CASE 17


    History: A pregnant patient presents with a high maternal alpha-fetoprotein measurement.

    1 . What should be included in the differential diagnosis of a lemon-shaped head? (Choose all that apply.)
    A. Normal fetus
    B. Trisomy 18
    C. Myelomeningocele
    D. Encephalocele
    E. Alobar holoprosencephaly
    2 . Which of the following is not an associated intracranial finding of myelomeningocele?
    A. Lemon sign
    B. Mega cisterna magna
    C. Banana sign
    D. Ventriculomegaly
    3 . Which of the following would be considered in the differential diagnosis of a lumbosacral mass with a lemon sign and a banana sign?
    A. Open neural tube defect
    B. Sacrococcygeal teratoma
    C. Amniotic band syndrome
    D. Limb-body wall complex
    4 . Which of the following is not a true statement concerning myelomeningocele?
    A. Sensitivity of the lemon sign and the banana sign is very high in identifying spina bifida.
    B. Lipomeningocele may not be associated with the lemon sign and spinal defects.
    C. With proper diagnosis and treatment, the prognosis of spina bifida is excellent.
    D. Ultrasound can predict the location and extent of spinal defects with a high degree of accuracy.

    ANSWERS

    CASE 17

    Myelomeningocele

    1 . A, B, C, and D
    2 . B
    3 . A
    4 . C

    References
    Kim SY, McGahan JP, Boggan JE, et al: Prenatal diagnosis of lipomyelomeningocele. J Ultrasound Med 2000; 19(11):801-805.
    http://www.ncbi.nlm.nih.gov/pubmed/11065270 (Accessed on June 4, 2012.)
    McGahan JP, Pilu G, Nyberg DA: Neuro tube defect and spine. In Nyberg DA, McGahan JP, Pretorius DH, et al. (eds): Diagnostic Imaging of Fetal Anomalies , Philadelphia, Lippincott Williams Wilkins, 2003, pp 230-334.
    Nicolaides KH, Campbell S, Gabbe SG: Ultrasound screening for spina bifida: cranial and cerebellar signs. Lancet 1986 2(8498):72-74.
    http://www.ncbi.nlm.nih.gov/pubmed/2425202 (Accessed on June 4, 2012.)

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 402-406.

    Comment

    Differential Diagnosis
    The differential diagnosis for lumbosacral masses is discussed in Case 10 : Sacrococcygeal Teratoma . The case here is an open neural tube defect in which there may be a cystic complex or solid mass originating from the lumbosacral spine. Associated cranial defects are present as shown by the lemon and banana signs (Figures A and B ). There is associated ventriculomegaly in a high percentage of cases. Other entities that may be considered include amniotic band syndrome and limb-body wall complex. In both of these entities, asymmetric defects and scoliosis are associated with disruption of the amnion. In limb-body wall complex, there is continuity of the fetus with the placenta surface. Finally, sacrococcygeal teratoma may manifest as either a cystic complex or a solid mass originating from the coccyx and could be considered in the differential diagnosis. Rare tumors such as lipoma of the cord or other cutaneous tumors may be considered in the differential diagnosis. However, none of these is usually associated with a lemon sign or banana sign.

    Ultrasound Features
    Ultrasound features of myelomeningocele, or spina bifida, include a lumbosacral mass that is complex cystic or solid. The neural foramen is splayed (Figure C ). The spinal cord is tethered or lies within the sacral region. There is an association of a posterior deformity in which the cerebellum is displaced into the cisterna magna and becomes effaced; this results in a cerebellum having the appearance of a banana (Figure B ). Before 24 weeks gestation, the cranium may have a lemon shape, in which the frontal bone is scalloped (Figure A ). The lemon sign suggests the possibility of spina bifida, but it is not pathognomonic for spina bifida. It rarely can be seen in normal fetuses, fetuses with trisomy 18, and fetuses with an encephalocele. Careful scanning of the rest of the fetus is needed. If a myelomeningocele is present, it may be associated with ventriculomegaly in the late second trimester in 70% to 80% of cases. Ventriculomegaly can be present at birth in 90% of cases.

    Prognosis and Management
    Even with appropriate diagnosis and treatment, a very high infant mortality rate is associated with spina bifida. Approximately 20% of live-born infants undergoing surgery die within the first year of life. Approximately one third of all infants die within the first 5 years. Death is usually related to respiratory failure, although there may be other etiologies. Individuals who survive often have lower limb dysfunction and problems with urinary incontinence.
    CASE 18


    Used with permission from Towner D, McGahan J, Rhee-Morris L, et al: The dynamic fetal brain . J Clin Ultrasound 35(5):238-244, 2007 .


    History: A patient presents with a third-trimester ultrasound scan that was performed at an outside institution and that shows increased intracranial fluid.

    1 . What should be included in the differential diagnosis? (Choose all that apply.)
    A. Hydranencephaly
    B. Alobar holoprosencephaly
    C. Aqueductal stenosis
    D. Arnold-Chiari malformation
    E. Dandy-Walker malformation
    2 . Which of the following is not a cause of ventriculomegaly?
    A. Infectious causes
    B. Chromosomal abnormalities
    C. Hydranencephaly
    D. In utero intraventricular hemorrhage
    3 . All of the following findings are associated with X-linked hydrocephalus except:
    A. Abduction of the thumb
    B. Abnormal facies
    C. Absence of septum pellucidum
    D. Associated with female fetuses
    4 . Which of the following should not be included in the management of fetuses with hydrocephalus?
    A. Careful ultrasound scan to rule out associated anomalies
    B. Perform fetal karyotyping
    C. Consider workup for in utero infection
    D. Cesarean section should always be considered

    ANSWERS

    CASE 18

    Aqueductal Stenosis

    1 . C, D, and E
    2 . C
    3 . D
    4 . D

    References
    Pilu G, Falco P, Gabrielli S, et al: The clinical significance of fetal isolated cerebral borderline ventriculomegaly: report of 31 cases and review of the literature. Ultrasound Obstet Gynecol 1999; 14(5):320-326.
    http://www.ncbi.nlm.nih.gov/pubmed/10623991 (Accessed on June 4, 2012.)
    Silan F, Ozdemir I, Lissens W: A novel L1CAM mutation with L1 spectrum disorders. Prenat Diagn 2005; 25(1):57-59.
    http://www.ncbi.nlm.nih.gov/pubmed/15662685 (Accessed on June 4, 2012.)
    Towner D, McGahan J, Rhee-Morris L, et al: The dynamic fetal brain. J Clin Ultrasound 2007; 35(5):238-244.
    http://www.ncbi.nlm.nih.gov/pubmed/17410587 (Accessed on June 4, 2012.)

    Cross-Reference
    Ultrasound: The REQUISITES, 2nd ed, pp 402-406, 410.

    Comment

    Differential Diagnosis
    The differential diagnosis depends on whether ventriculomegaly is mild (ventricular size between 10 and 15 mm) or moderate to severe (ventricular size 15 mm). Any etiology of ventriculomegaly could be considered, including Arnold-Chiari malformation and Dandy-Walker malformation. Arnold-Chiari malformation has a lemon sign. Dandy-Walker malformation has a posterior fossa cyst. However, there are usually associated findings that are easily recognized in these entities.

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