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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.

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    • 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.


    Placenta previa
    Ovarian pregnancy
    Intrauterine device
    Cervical pregnancy
    Interstitial pregnancy
    Ovarian torsion
    Autosomal recessive polycystic kidney
    Choledochal cysts
    Uterus didelphys
    Ectopia cordis
    Vesicoureteral reflux
    Sacrococcygeal teratoma
    Abdominal mass
    Abdominal distension
    Overriding aorta
    Double outlet right ventricle
    Pericardial effusion
    Neural tube defect
    VACTERL association
    Transverse plane
    Complications of pregnancy
    Agenesis of the corpus callosum
    Congenital diaphragmatic hernia
    Hypoplastic left heart syndrome
    Hydrops fetalis
    Pulmonary sequestration
    Ovarian hyperstimulation syndrome
    Abdominal wall defect
    Choroid plexus cyst
    Sex cord-gonadal stromal tumour
    Gestational trophoblastic disease
    Urinary retention
    Acute pancreatitis
    Hydatidiform mole
    Differential diagnosis
    Gastrointestinal bleeding
    Ventricular septal defect
    Congenital heart defect
    Intracranial hemorrhage
    Prenatal diagnosis
    Tuberous sclerosis
    Pleural effusion
    Ovarian cyst
    Bowel obstruction
    Congenital disorder
    Health care
    Heart failure
    Tetralogy of Fallot
    Cleft lip and palate
    Disseminated intravascular coagulation
    Pulmonary embolism
    Esophageal atresia
    Intrauterine growth restriction
    Medical ultrasonography
    Conjoined twins
    Prune belly syndrome
    Multiple birth
    Heart disease
    Ectopic pregnancy
    Polycystic ovary syndrome
    X-ray computed tomography
    Turner syndrome
    Varicose veins
    Rheumatoid arthritis
    Pelvic inflammatory disease
    Magnetic resonance imaging
    Muscular dystrophy
    Down syndrome
    Placenta accreta
    Spina bifida


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    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
    Obstetric and Gynecologic Ultrasound

    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

    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).

    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
    [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 womenSERIES 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, MBABOOK 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
    David M. Yousem, MD, MBAPREFACE
    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
    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/.A C K N O W L E D G M E N T S
    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.
    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.
    Cover Page
    Title Page
    Copyright Page
    Dedication Page
    Series Foreword
    Book Foreword
    Opening Round
    Fair Game
    Index of Cases
    Index of TermsOpening RoundCASE 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 mmC. 8 to 10 mm
    4. What is the most common endometrial pathology resulting from tamoxifen use?
    A. Endometrial hyperplasia
    B. Subendometrial cysts
    C. PolypsANSWERS
    CASE 1
    1. A, B, and C
    2. B
    3. B
    4. C
    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;
    http://www.ncbi.nlm.nih.gov/pubmed/16567436 (Accessed on May 29, 2012.).
    Ultrasound: The REQUISITES, 2nd ed, pp 542, 544, 546.
    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 showedthat 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 2Used 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
    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 sequestrationD. 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. CardiovascularANSWERS
    CASE 2
    Pleural Effusions
    1. B and D
    2. D
    3. B
    4. A
    Aubard Y, Derouineau I, Aubard V, et al: Primary fetal hydrothorax: a literature
    review and proposed antenatal clinical strategy. Fetal Diagn Ther. 1998;
    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;
    http://www.ncbi.nlm.nih.gov/pubmed/17605152 (Accessed on May 29, 2012.).
    Ultrasound: The REQUISITES, 2nd ed, pp 270, 419-422.
    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 3Used 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
    Akın MA, Akın 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):
    http://www.ncbi.nlm.nih.gov/pubmed/18970932 (Accessed on May 29, 2012.).
    Ultrasound: The REQUISITES, 2nd ed, p 447.
    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 4Used 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
    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 obstructionANSWERS
    CASE 4
    Ureteropelvic Junction Obstruction
    1. A, B, C, and D
    2. C
    3. A
    4. D
    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.).
    Ultrasound: The REQUISITES, 2nd ed, p 465.
    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 ureterand 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
    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 karyotypeANSWERS
    CASE 5
    Choroid Plexus Cyst
    1. A, B, and C
    2. D
    3. A
    4. B
    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;
    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.).
    Ultrasound: The REQUISITES, 2nd ed, pp 395–397.
    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
    welldemarcated 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
    welldemarcated 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
    highquality 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
    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
    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
    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.).
    Ultrasound: The REQUISITES, 2nd ed, pp 406-410, 419-422.
    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 7History: 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
    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
    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. ChorioamnionitisANSWERS
    CASE 7
    1. A, C, and D
    2. A
    3. B
    4. D
    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–
    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.).
    Ultrasound: The REQUISITES, 2nd ed, pp 458, 460.
    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
    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 8History: A 55-year-old, postmenopausal woman presents with a palpable
    rightsided 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
    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 abscessD. Dermoid
    3. What does the spectral waveform from the soft tissue component of the mass
    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 cystsANSWERS
    CASE 8
    Ovarian Cancer
    1. A, B, C, and D
    2. A
    3. B
    4. D
    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;
    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.).
    Ultrasound: The REQUISITES, 2nd ed, pp 579-583.
    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
    highresistance 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 9History: 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
    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. AdhesionsANSWERS
    CASE 9
    Acute Appendicitis
    1. A and B
    2. B
    3. A
    4. B
    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,
    Ultrasound: The REQUISITES, 2nd ed, pp 224-225.
    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
    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
    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 tumorANSWERS
    CASE 10
    Sacrococcygeal Teratoma
    1. A, B, D, and E
    2. B
    3. B
    4. C
    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;
    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–
    http://www.ncbi.nlm.nih.gov/pubmed/19122459 (Accessed on May 30, 2012.).
    Ultrasound: The REQUISITES, 2nd ed, pp 408-410.
    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
    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
    A. Dandy-Walker malformation
    B. Dandy-Walker variant
    C. Arachnoid cyst
    D. Mega cisterna magna