Radcases Ultrasound Imaging E-Book

Nami R. Azar

• Herausgeber: Thieme Medical Publishers
• Kategorie: Fachliteratur
• Sprache: Englisch

Veröffentlichungsjahr: 2015

Beschreibung

All the key Radiology cases for your rounds, rotations, and exams

Ultrasound Imaging refines your ultrasound diagnostic skills and prepares you for board exams in radiology.

Features of Ultrasound Imaging:

• Covers a wide range of radiological specialties, including renal, gastrointestinal, genitourinary, thyroid, vascular, pediatric, and obstetric
• Each case includes valuable tips to help readers properly interpret ultrasound images and avoid potential pitfalls
• Nearly 100 high-quality color illustrations and 350 black and white radiographs demonstrating key ultrasound imaging cases

RadCases contains cases selected to simulate everything that you'll see on your rounds, rotations, and exams. RadCases also helps you identify the correct differential diagnosis for each case— including the most critical.

RadCases covers:

• Cardiac Imaging · Interventional Radiology · Musculoskeletal Radiology · Neuro Imaging · Thoracic Imaging · Pediatric Imaging · Gastrointestinal Imaging · Breast Imaging · Nuclear Medicine · Ultrasound Imaging · Head and Neck Imaging · Genitourinary Imaging

Each RadCases title features 100 carefully selected, must-know cases documented with clear, high-quality radiographs. The organization provides maximum ease of use for self-assessment. Each case begins with the clinical presentation on the right-hand page; simply turn the page for imaging findings, differential diagnoses, the definitive diagnosis, essential facts, and more.

This RadCases book comes with a code providing access to additional online cases: 100 in this book plus 150 more cases.

Learn your cases, diagnose with confidence, and pass your exams. RadCases.

This print book includes complimentary access to a digital copy on https://medone.thieme.com.

Publisher's Note: Products purchased from Third Party sellers are not guaranteed by the publisher for quality, authenticity, or access to any online entitlements included with the product.

Leseprobe

To access the additional media content available with this e-book via Thieme MedOne, please use the code and follow the instructions provided at the back of the e-book.

RadCases Ultrasound Imaging

Edited by

Nami Azar, MD

Associate Professor of RadiologyDirector, Center for Interventional RadiologySection Head, UltrasoundAbdominal and Cross-Sectional Intervention Fellowship DirectorDepartment of RadiologyUniversity Hospitals Case Medical CenterCleveland, Ohio

Carolyn Donaldson, MD

Clinical Assistant ProfessorUniversity of Chicago, Pritzker School of MedicineChicago, IllinoisNorthShore University HealthSystemEvanston, Illinois

Series Editors

Jonathan Lorenz, MD

Associate Professor of RadiologyDepartment of RadiologyThe University of ChicagoChicago, Illinois

Hector Ferral, MD

Senior Clinical EducatorNorthShore University HealthSystemEvanston, Illinois

ThiemeNew York • Stuttgart • Delhi • Rio

Executive Editor: William LamsbackManaging Editor: J. Owen Zurhellen IVEditorial Assistant: Heather AllenSenior Vice President, Editorial and Electronic Product Development: Cornelia SchulzeProduction Editor: Teresa Exley, Maryland CompositionInternational Production Director: Andreas SchabertInternational Marketing Director: Fiona HendersonDirector of Sales, North America: Mike RosemanInternational Sales Director: Louisa TurrellSenior Vice President and Chief Operating Officer: Sarah VanderbiltPresident: Brian D. ScanlanCompositor: MPS Limited

Library of Congress Cataloging-in-Publication Data

RadCases ultrasound imaging/edited by Nami Azar, Carolyn Donaldson.    p.; cm.—(RadCases)Ultrasound imagingISBN 978-1-60406-322-6I. Azar, Nami, editor. II. Donaldson, Carolyn(Diagnostic radiologist), editor. III. Title: Ultrasound imaging.IV. Series: RadCases.[DNLM: 1. Ultrasonography—Case Reports. 2. Diagnosis, Differential—Case Reports. WN 208]RC78.7.U4616.07’543—dc23      2014025179

Copyright © 2015 by Thieme Medical Publishers, Inc.Thieme Publishers New York333 Seventh AvenueNew York, NY 10001 USA1-800-782-3488, [email protected]

Thieme Publishers StuttgartRüdigerstrasse 14 70469 Stuttgart, Germany+49 [0]711 8931 421, [email protected]

Thieme Publishers DelhiA-12, Second Floor, Sector -2, NOIDA -201301Uttar Pradesh, India+91 120 45 566 00, [email protected]

Thieme Publishers Rio, Thieme Publicações Ltda.Argentina Building 16th floor, Ala A, 228 Praia do BotafogoRio de Janeiro 22250-040 Brazil+55 21 3736-3631

Printed in China by Everbest Printing Ltd.

ISBN 978-1-60406-322-6

Also available as an e-book:eISBN 978-1-60406-323-3

Important note: Medicine is an ever-changing science undergoing continual development. Research and clinical experience are continually expanding our knowledge, in particular our knowledge of proper treatment and drug therapy. Insofar as this book mentions any dosage or application, readers may rest assured that the authors, editors, and publishers have made every effort to ensure that such references are in accordance with the state of knowledge at the time of production of the book.

Nevertheless, this does not involve, imply, or express any guarantee or responsibility on the part of the publishers in respect to any dosage instructions and forms of applications stated in the book. Every user is requested to examine carefully the manufacturers’ leaflets accompanying each drug and to check, if necessary in consultation with a physician or specialist, whether the dosage schedules mentioned therein or the contraindications stated by the manufacturers differ from the statements made in the present book. Such examination is particularly important with drugs that are either rarely used or have been newly released on the market. Every dosage schedule or every form of application used is entirely at the user's own risk and responsibility. The authors and publishers request every user to report to the publishers any discrepancies or inaccuracies noticed. If errors in this work are found after publication, errata will be posted at www.thieme.com on the product description page.

Some of the product names, patents, and registered designs referred to in this book are in fact registered trademarks or proprietary names even though specific reference to this fact is not always made in the text. Therefore, the appearance of a name without designation as proprietary is not to be construed as a representation by the publisher that it is in the public domain.

This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow limits set by copyright legislation without the publisher's consent is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

To our daughters, Marie and Julia, for their resilience and many sacrifices on behalf of my work. I hope that you too will be passionate about whatever it is you do in life. And to Jim, who has always been my rock.

Carolyn Donaldson, MD

I would like to dedicate this book to my wife, Dana, and my daughter, Nelly, for their endless support. Great thanks for my friends in the ultrasound department at University Hospitals of Cleveland for the amazing work, great cases, and continuous encouragement.

Nami Azar, MD

RadCases Series Preface

The ability to assimilate detailed information across the entire spectrum of radiology is the Holy Grail sought by those preparing for the American Board of Radiology examination. As enthusiastic partners in the Thieme RadCases Series who formerly took the examination, we understand the exhaustion and frustration shared by residents and the families of residents engaged in this quest. It has been our observation that despite ongoing efforts to improve Web-based interactive databases, residents still find themselves searching for material they can review while preparing for the radiology board examinations and remain frustrated by the fact that only a few printed guidebooks are available, which are limited in both format and image quality. Perhaps their greatest source of frustration is the inability to easily locate groups of cases across all subspecialties of radiology that are organized and tailored for their immediate study needs. Imagine being able to immediately access groups of high-quality cases to arrange study sessions, quickly extract and master information, and prepare for theme-based radiology conferences. Our goal in creating the RadCases Series was to combine the popularity and portability of printed books with the adaptability, exceptional quality, and interactive features of an electronic case-based format.

The intent of the printed book is to encourage repeated priming in the use of critical information by providing a portable group of exceptional core cases that the resident can master. The best way to determine the format for these cases was to ask residents from around the country to weigh in. Overwhelmingly, the residents said that they would prefer a concise, point-by-point presentation of the Essential Facts of each case in an easy-to-read, bulleted format. This approach is easy on exhausted eyes and provides a quick review of Pearls and Pitfalls as information is absorbed during repeated study sessions. We worked hard to choose cases that could be presented well in this format, recognizing the limitations inherent in reproducing high-quality images in print. Unlike the authors of other case-based radiology review books, we removed the guesswork by providing clear annotations and descriptions for all images. In our opinion, there is nothing worse than being unable to locate a subtle finding on a poorly reproduced image even after one knows the final diagnosis.

The electronic cases expand on the printed book and provide a comprehensive review of the entire subspecialty. Thousands of cases are strategically designed to increase the resident's knowledge by providing exposure to additional case examples—from basic to advanced—and by exploring “Aunt Minnie's,” unusual diagnoses, and variability within a single diagnosis. The search engine gives the resident a fighting chance to find the Holy Grail by creating individualized, daily study lists that are not limited by factors such as radiology subsection. For example, tailor today's study list to cases involving tuberculosis and include cases in every subspecialty and every system of the body. Or study only thoracic cases, including those with links to cardiology, nuclear medicine, and pediatrics. Or study only musculo-skeletal cases. The choice is yours.

As enthusiastic partners in this project, we started small and, with the encouragement, talent, and guidance of Tim Hiscock at Thieme, we have continued to raise the bar in our effort to assist residents in tackling the daunting task of assimilating massive amounts of information. We are passionate about continuing this journey, hoping to expand the cases in our electronic series, adapt cases based on direct feedback from residents, and increase the features intended for board review and self-assessment. As the American Board of Radiology converts its certifying examinations to an electronic format, our series will be the one best suited to meet the needs of the next generation of overworked and exhausted residents in radiology.

Jonathan Lorenz, MDHector Ferral, MDChicago, IL

Preface

This book of the RadCases series is a comprehensive review of all specialties from vascular ultrasound (US) to obstetrics. The advantage of this US review is that it includes video clips, which is how the boards are now conducted. Although the RadCases series typically presents pathology, some normal cases are included. It is important to be able to recognize the normal appearance of things such as the endometrium and the different carotid waveforms.

Unlike other imaging modalities, US is widely used in multiple medical specialties by many persons of varied levels of expertise. Many urologists and gynecologists have ultrasound machines in their offices. Currently, there is discussion about medical students being given a portable US machine at the same time as they receive their stethoscopes. Therefore, it is important as radiologists that we maintain a level of expertise in ultrasound.

Ultrasound is the least sexy imaging modality in radiology. It is labor intensive, operator dependent, and the random planes of section make it difficult for the radiologist to interpret. With the RVU pressure, radiologists shy away from scanning. However, because of the lack of radiation, need for contrast, and the relatively inexpensive cost, US will not be phased out by CT or MR. With the image optimization provided by harmonics, Doppler, and elastography, US continues to evolve, ensuring its staying power.

The history of US is relatively short. Sonar, the initial use of US, was developed by the U.S. Navy in the 1950s to direct submarines. US was first used in clinical medicine in the 1970s. US equipment continues to improve with imaging optimization, including harmonics, and the diagnostic abilities of ultrasound allow for its staying power.

All of the cases are real-life patients whose studies have been read in the last several years. We are confident they will prepare you for the boards. They will provide confidence in your diagnostic capabilities practicing radiology, especially US.

Best of luck on boards,

Carolyn Donaldson, MDNami Azar, MD

Acknowledgements

I would like to acknowledge Hector Ferral for inviting me to coauthor this ultrasound book of the RadCases series. To Marie, who launched me electronically on this project from the start. Julia, who spent hours studying with me at Starbucks. To the University of Chicago residents and fellows, who reviewed and edited my cases while rotating on the ultrasound service. And, lastly, to the sonographers whose talent and tireless attention to detail allow me to look like I know what I am doing.

Carolyn Donaldson, MD

Thank you to Dr. Noam Lazebnik for your contributions to the cases.

Nami Azar, MD

Table of Contents

RadCases Series Preface

Preface

Acknowledgments

Case 1

Case 2

Case 3

Case 4

Case 5

Case 6

Case 7

Case 8

Case 9

Case 10

Case 11

Case 12

Case 13

Case 14

Case 15

Case 16

Case 17

Case 18

Case 19

Case 20

Case 21

Case 22

Case 23

Case 24

Case 25

Case 26

Case 27

Case 28

Case 29

Case 30

Case 31

Case 32

Case 33

Case 34

Case 35

Case 36

Case 37

Case 38

Case 39

Case 40

Case 41

Case 42

Case 43

Case 44

Case 45

Case 46

Case 47

Case 48

Case 49

Case 50

Case 51

Case 52

Case 53

Case 54

Case 55

Case 56

Case 57

Case 58

Case 59

Case 60

Case 61

Case 62

Case 63

Case 64

Case 65

Case 66

Case 67

Case 68

Case 69

Case 70

Case 71

Case 72

Case 73

Case 74

Case 75

Case 76

Case 77

Case 78

Case 79

Case 80

Case 81

Case 82

Case 83

Case 84

Case 85

Case 86

Case 87

Case 88

Case 89

Case 90

Case 91

Case 92

Case 93

Case 94

Case 95

Case 96

Case 97

Case 98

Case 99

Case 100

Further Readings

Index

Case 1

Clinical Presentation

A 49-year-old woman with history of hepatitis C presents for liver evaluation.

Further Work-up

Imaging Findings

(A) Gray scale ultrasound image shows signs of liver cirrhosis and ascites. Cystic changes and wall thickening (white arrow) are noted in the gallbladder. Gallstone is also present (red arrow). (B) Color ultrasound demonstrates flow within the cystic lesion in the wall (white arrow). (C) Pulse Doppler tracing confirms the presence of flow, demonstrating monophasic (arrow), venous flow pattern (similar to the portal vein).

Differential Diagnosis

Vascular lesions of the gallbladder include wall varices, diffuse adenomyomatosis, and gallbladder cancer.

• Gallbladder varices: Usually seen as portosystemic collateral, a monophasic flow is usually present.

• Diffuse adenomyomatosis: The diffuse form is seen in 20% of patients with adenomyomatosis. The presence of twinkle artifact (noise on Doppler tracing) is suggestive of the diagnosis.

• Gallbladder wall carcinoma: Irregular wall thickening is seen. The presence of invasion and arterial flow raises the possibility of malignancy.

Essential Facts

• Likely associated with portal hypertension and or portal vein thrombosis. Rarely as a normal pathway.

• Portosystemic shunt linking the cystic vein branch of the portal vein to the anterior abdominal wall systemic collaterals.

• Could be formed as bypass around a focally thrombosed extrahepatic segment of the portal vein.

• Gallbladder varices may be related to dilated veins due to back pressure within the portal venous system in patients with chronic portal hypertension.

Pearls &Pitfalls

The presence of portovenous flow in the gallbladder wall with cystic changes is characteristic of gallbladder varices.

The presence of color in the gallbladder without characterizing the waveform/type of flow could be misleading with potential misdiagnosis.

Case 2

Clinical Presentation

A 15-year-old girl with enlarged left thyroid on exam.

Imaging Findings

(A) Transverse image of the thyroid gland reveals an enlarged left lobe with distinctly different echotexture than the normal right lobe. Longitudinal (B) and transverse (C) images reveal a heterogeneous enlarged left lobe with innumerable echogenic foci throughout the gland. (D) An enlarged lymph node lateral to the thyroid is heterogeneous and contains microcalcifications. Asterisk denotes the jugular vein.

Differential Diagnosis

• Metastatic papillary thyroid cancer: Diffuse psammomatous calcifications or microcalcifications in the thyroid and a cervical lymph node is consistent with metastatic papillary thyroid cancer.

• Diffuse thyroiditis: The echotexture of the thyroid gland will be coarse or inhomogeneous in the setting of diffuse thyroiditis but punctate echogenic foci will not be present. It is usually symmetric bilaterally.

• Chronic lymphocytic thyroiditis (also known as Hashimoto's thyroiditis): A diffusely heterogeneous echotexture is seen with Hashimoto's thyroiditis. It is usually bilateral and fairly symmetric.

Essential Facts

• Microcalcifications even without an associated mass are highly suspicious for papillary thyroid cancer and warrant FNA.

• Psammoma bodies are laminated, basophilic, spherical concretions and are a characteristic finding of papillary thyroid carcinoma.

• Most microcalcifications seen with thyroid ultrasound represent psammoma bodies and are highly sensitive for malignancy.

• Diffuse microcalcifications from papillary thyroid cancer have a significant incidence of metastatic cervical nodes.

• Microcalcifications and cystic changes within a lymph node are suspicious for metastatic involvement.

• Loss of the normal fatty hilum and rounded shape of a lymph node are suspicious features of lymph nodes.

Pearls &Pitfalls

Psammomatous calcifications are highly specific for papillary thyroid cancer (95% specific).

Most psammomatous calcifications are seen in solid nodules.

A cluster of microcalcifications in the thyroid gland is suspicious for malignancy even without an obvious mass lesion.

Psammomatous calcifications can be seen in metastatic lymph nodes, including nonenlarged nodes.

When areas of microcalcification are detected within the thyroid gland, evaluation of the cervical lymph nodes should be performed.

Case 3

Clinical Presentation

A 82-year-old female presents with hematuria.

Further Work-up

Imaging Findings

(A–F) Ultrasound images show a hypoechoic lesion in the posterior aspect of the right kidney (arrows, image A). Filling defect within the renal vein is noted extending into the IVC (arrows, image B). The invasion into the IVC is confirmed on color Doppler (arrows, image C). Contrast-enhanced MRI images of the kidneys show a hypervascular, enhancing mass in the posterior aspect of the right kidney (arrows, image D) with large filling defect in the renal vein (arrow, image E) with extension into the hepatic and thoracic segments of the IVC (arrows, image F).

Differential Diagnosis

• Renal cell carcinoma (RCC) with extension to the IVC: Appears as a hypoechoic, isoechoic, or echogenic mass lesion, extension into the IVC/periaortic adenopathy in suggestive of the diagnosis. Accurate staging is important for surgical planning.

• Renal lymphoma: The most common appearance is a focal renal mass, renal invasion from retroperitoneal mass, and/or infiltrative type. Renal involvement is secondary from either hematogenous or direct extension.

• Leiomyosarcoma of the IVC with extension to the kidney: Is an uncommon tumor with poor outcome. Appears as a filling defect in the IVC, with possible extension into the renal vein. The kidney could appear enlarged secondary to limited flow in the renal vein.

Essential facts

• Represent 3% of all adult malignancies and 86% of renal malignancies.

• Associated with von Hippel-Lindau (24 to 45% of patients will develop RCC).

• Appears as solid, hypoechoic, isoechoic, or hyperechoic mass.

• Increase flow on Doppler usually present, lack of flow doesn't exclude malignancy.

• Unilocular cystic RCC will show debris and irregular thick wall.

• Multilocular RCC will show cystic mass with septations. Flow within the septations could be seen on Doppler.

Pearls &Pitfalls

Doppler and gray scale evaluation of the renal vein and IVC should be performed in the presence of renal mass lesion to exclude extension.

Unilocular cystic RCC could be misinterpreted as hemorrhagic cyst. The presence of irregular, thick wall is suggestive of malignancy.

Case 4

Clinical Presentation

A 38-year-old black man with nontender scrotal enlargement.

Further Work-up

Imaging Findings

(A, B) Longitudinal gray scale images of each testicle demonstrates innumerable small hypoechoic lesions bilaterally. Similar lesions are present in the epididymis. (C) A right epididymal lesion is measured in image. (D) Coronal reformatted computed tomography (CT) image of the chest demonstrates bulky hilar and right paratracheal lymphadenopathy. Arrow denotes right paratracheal lymphadenopathy.

Differential Diagnosis

• Genitourinary sarcoidosis: Tuberculosis, fungal infections, syphilis, LGV, Wegeners granulomatous and sarcoidosis can all present with findings in the testicles. The epididymis is the most common site for involvement in genitourinary (GU) sarcoidosis. The bulky mediastinal and particularly right paratracheal lymphadenopathy seen on the subsequent CT of the chest are classic for sarcoidosis.

• Lymphoma or leukemia: Statistically, leukemia or lymphoma would be the most common cause for bilateral testicular masses. The testicles contain a barrier to chemo-therapeutic agents that allows them to harbor leukemic or lymphomatous cells. Ultrasound findings in the setting of leukemic or lymphomatous infiltration of testicles would be similar to the images above. It usually occurs in older patients with a history of leukemia or lymphoma.

• Metastatic disease to the testicles: Usually occurs in the setting of widespread metastatic disease. Metastases to the testicles occur with numerous cancers but lung and prostate are the most frequent. Most testicular metastases are clinically silent and discovered at autopsy.

Essential Facts

• Sarcoidosis is a chronic disease of unknown etiology resulting in noncaseating granulomas involving multiple organ systems.

• Incidence of sarcoidosis in the United States is 1 in 10,000. African Americans have a 3 to 20 times higher incidence; women have a 10 times greater frequency than men.

• Involvement of the GU tract is rare, occurring in < 1% of patients with sarcoidosis. Sarcoidosis can affect any organ of the GU tract. The most common site of involvement is the epididymis, followed by the testes. It is associated with infertility.

• Sarcoidosis can mimic many conditions that require aggressive or invasive treatments. Biopsy may be required to exclude malignancy.

• Sarcoidosis is generally a self-limited condition and is most commonly treated conservatively with antiinflammatory medications, including steroids.

• Sarcoidosis is usually diagnosed with bilateral hilar lymphadenopathy on chest radiograph. Patients with sarcoidosis usually present with dyspnea, cough, chest pain, or weight loss.

Pearls &Pitfalls

In the setting of bilateral testicular masses, involvement of the epididymis will invariably be present with sarcoidosis.

GU involvement of sarcoidosis occurs in the setting of other organ involvement, most typically the lungs with lymphadenopathy, as in this case.

Testicular sarcoid typically occurs in black men ages 20 to 40, the same age group as testicular cancer.

Case 5

Clinical Presentation

A 35-year-old woman presents with pelvic pain and fever.

Further Work-up

Imaging Findings

(A, B) Ultrasound images of the pelvis using transabdominal and transvaginal ultrasound show large, complex cystic lesion in the cul-de-sac (white arrows) with layering of low-level echoes and fluid-fluid level (red arrow). No gross evidence of air is noted on the current study. (C) Follow-up computed tomography of the pelvis demonstrates the same lesion with rim enhancement (white arrows). No evidence of intraluminal air is noted on the current study.

Differential Diagnosis

• Pelvic abscess: Appears as complex fluid collection with low-level echoes; no internal flow is seen on color images; peripheral flow occasionally can be seen.

• Endometrioma: Diffuse low-level echo with fluid-fluid levels is the typical sonographic appearance. The presence of wall echogenic reflectors/calcifications and multiloculation is suggestive of the diagnosis.

• Cystic neoplasm: Appears as complex collection with multiple irregular septations. The presence of arterial flow within the septations and nodularity is suggestive of the diagnosis.

Essential Facts

• The sources of pelvic abscesses include postoperative abscess, perforating appendicitis, diverticulitis, tubo-ovarian inflammation, Crohn disease, and internal bowel fistula due to irradiation.

• Patients present with fever and elevated white blood cells.

• It appears as complex fluid collection with occasional peripheral flow.

• Local tenderness during pelvic ultrasound is suggestive of the diagnosis.

• Imaging-guided drainage and antibiotics provide safe and effective treatment approach.

Pearls &Pitfalls

Lack of internal arterial flow within a pelvic mass does not exclude cystic neoplasm.

A necrotic pelvic mass could be misinterpreted as pelvic abscess or endometrioma.

Case 6

Clinical Presentation

A 32-year-old woman with sudden-onset left lower quadrant pain. Last menstrual period was 3 weeks ago.

Imaging Findings

(A–C) The left ovary is enlarged due to a complex cystic lesion. The lesion contains layering debris in the sagittal (or longitudinal) view and fine interdigitating lines seen in both views (arrows). With color Doppler imaging, there is no internal vascularity. The lesion resolved on a follow-up study.

Differential Diagnosis

• Hemorrhagic cyst: Hemorrhagic cysts often have internal echoes with a pattern of fine interdigitating lines as seen in the above lesion. The debris is hemorrhage within the cyst. Because the lesion resolved on a follow-up study, it is consistent with a hemorrhagic cyst.

• Endometrioma: Low-level echoes typical of an endometrioma are present in the dependent portion of the lesion. Fine interdigitating lines are not typical of an endometrioma. An endometrioma would persist on a follow-up study.

• Dermoid or teratoma: Dermoids can contain a fluid layer. These layers are more distinct than the dependent debris in the above lesion. The more echogenic layering fat would be in the nondependent position in a dermoid.

Essential Facts

• Hemorrhagic cysts are the most common etiology for a complex cystic ovarian lesion. They are usually a result of hemorrhage into a corpus luteum or a ruptured follicle and can cause acute pain.

• The appearance of acute hemorrhage within a cyst is varied. The fine interdigitating lines are typical of hemorrhage. A retracting clot is also classic for hemorrhage.

• No flow is present within a hemorrhagic cyst with color or spectral Doppler imaging.

• Classic hemorrhagic cysts < 5 cm do not need to be followed up. They should be considered physiologic in a premenopausal woman.

• Hemorrhagic cysts typically resolve within 6 to 8 weeks. Therefore, if a complex cystic lesion is > 5 cm, a follow-up ultrasound in 6 to 12 weeks should be performed.

• Hemoperitoneum can result with rupture and hemorrhage of a cyst. Rarely, this requires surgical intervention.

Other Imaging Findings

• Computed tomography (CT) is not as sensitive as ultrasound in detection of a hemorrhagic cyst. The reticular pattern is not seen on CT. A hemorrhagic cyst can be isodense with the ovary and therefore not visible on CT.

Pearls &Pitfalls

If a lesion is not classic for hemorrhage, recommend follow-up. A hemorrhagic cyst will resolve (or decrease considerably in size).

The thin fibrin strands seen with hemorrhage can be confused with septations seen in other lesions including malignancy. Septations are usually thicker and may demonstrate flow with color.

Case 7

Clinical Presentation

A 45-year-old woman presents with left mandibular swelling.

Further Work-up

Imaging Findings

(A, B) Ultrasound image near the left angle of the mandible demonstrates a prominent and serpiginous anechoic structure (red arrow) within the submandibular gland with small echogenic focus (yellow arrow) that presents posterior shadowing. Color Doppler assessment reveals flow surrounding this tortuous structure. Findings are consistent with a dilated submandibular gland duct (Wharton duct) with central obstructing sialolith. (C, D) Follow-up contrast-enhanced computed tomography imaging of the neck demonstrates again a dilated left submandibular gland duct (red arrow) and a 5 mm sialolith (yellow arrow).

Differential Diagnosis

• Sialolithiasis: Commonly seen in the submandibular gland. A bright echogenic focus with distal shadowing is noted in 94% of cases with associated ductal dilatation.

• Submandibular acute inflammation: The etiology can be viral or bacterial. Ultrasound shows diffuse enlargement of the gland with a decrease in echogenicity. Associated lymph node enlargement can be seen sonographically.

• Chronic inflammation: The patients present with intermittent, painless swelling of the gland.

Essential Facts

• Seventy to 95% of salivary gland stones occur in the submandibular gland.

• Both the main duct and intraglandular ductules can be affected

• Common symptoms include mandibular swelling triggered by eating.

• Echogenic rim with posterior acoustic shadow is the main sonographic feature of a calculus.

• The stone is identified in 60 to 80% on plain films and in almost 100% of CTs.

• Chronic obstruction might cause cystic degeneration in the gland.

• In the case of chronic painful swelling, Sjogren's syndrome should be considered.

Pearls &Pitfalls

The swollen gland can become heterogeneously hypoechoic due to edema.

A stone impacted at the ductal ostium may not be well depicted on sonography, but many cases have associated main duct dilation.

Case 8

Clinical Presentation

A 31-year-old woman with left lower quadrant pain. Last menstrual period was 3 weeks ago.

Imaging Findings