Search Results

Headache and Dizziness • Xray of the Week 51 year old male with a left cerebellar mass. What is the diagnosis? Figure1. Left cerebellar Mass. Diagnosis? Figure1.A: MRI- T2 weighted axial image shows cystic lesion in left cerebellar hemisphere with mass effect (green arrow). There is hydrocephalus (not shown). B: MRI- T1 weighted axial image shows cystic lesion in left cerebellar hemisphere with mass effect. There is an enhancing mural nodule with small serpentine flow voids (green arrow). C: MRI- T1 sagittal image shows cystic lesion in left cerebellar hemisphere with mass effect. There is an enhancing mural nodule (green arrow). Approximately 20-25% of people with cerebellar hemangioblastomas have von Hippel–Lindau disease, and as in this case, the majority (75-80%) are sporadic. 44-72% of patients with von Hippel–Lindau (vHL disease have at least one cerebellar hemangioblastoma, and 13-59% have at least one spinal hemangioblastoma. 80% of people with spinal hemangioblastomas have vHL disease. When associated with vHL disease, they occur at a younger age and have a worse prognosis. The vast majority (95%) of intracranial hemangioblastomas occur in posterior fossa with 85% in the cerebellar hemisphere, 10% in the cerebellar vermis, and 5% in the medulla. On imaging studies, hemangioblastomas may be solid, cystic, hemorrhagic, or mixed. Seen in about 60% of cases, the classic appearance is a cystic lesion with a solid enhancing mural nodule. About 40% of cases consist only of the enhancing nodule. Often there are serpentine flow voids within the nodule due to the highly vascular nature of the tumor. Surgical resection is usually curative, however, up to 25% of cases have subsequent local recurrence. References: 1. Ho VB, Smirniotopoulos JG, Murphy FM et-al. Radiologic-pathologic correlation: hemangioblastoma. AJNR Am J Neuroradiol. 13 (5): 1343-52. 2. Leung RS, Biswas SV, Duncan M et-al. Imaging features of von Hippel-Lindau disease. Radiographics. 28 (1): 65-79. Kevin M. Rice, MD is the president of Global Radiology CME. He has served in many leadership roles including Chair of the Radiology Department and Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. He has been a radiologist with Renaissance Imaging Medical Associates since 2000. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M Rice, MD

RUQ Pain in 89F • Xray of the Week This 89 year old female presented to the Emergency Department with right upper quadrant abdominal pain. What is the differential diagnosis? Fig. 1 CT: Diffuse gallbladder wall thickening with surrounding mesenteric infiltration and lymphadenopathy. The patient underwent a cholecystectomy and the pathology was gallbladder carcinoma. Fig. 2 CT: Diffuse gallbladder wall thickening with surrounding mesenteric infiltration (red arrow) and lymphadenopathy (blue arrow). The patient underwent a cholecystectomy and the pathology was gallbladder carcinoma. Gallbladder carcinoma is an uncommon malignancy, which usually presents at an advanced stage. Greater than 90% of the histologic type is adenocarcinoma with squamous comprising most of the remainder. Most cases occur in the elderly population with F:M ratio of 4:1. At least 75% are associated with gallstones. Fig. 3 Porcelain gallbladder. CT scan with dense calcification throughout the wall of the gallbladder. Porcelain gallbladder (Fig. 3) is also highly correlated with gallbladder cancer as up to 25% of patients with diffuse calcification of the gallbladder wall go on to develop gallbladder cancer. Symptoms occur late in the disease and are usually related to local invasion resulting in biliary obstruction, gastric outlet obstruction or adjacent bowel obstruction. Prognosis is extremely poor with 5 year survival less than 5%. Fig. 4 Left: Ultrasound with polypoid masses in the gallbladder. Right: Axial CT and MRI with contrast. Polypoid masses in the gallbladder. Fig. 5 Axial CT with contrast. Large mass in the gallbladder fossa with direct extension and invasion of the adjacent liver. Case courtesy of Radswiki, a href=httpradiopaedia.orgRadiopaedia.orga. From the case a href=httpradiopaedia.orgcases11438rID 11438a Imaging features on CT, MRI, and US include focal or diffuse gallbladder wall thickening or a polypoid mass in the gallbladder lumen (Fig. 4). Due to late presentation, the majority of cases have a large mass replacing the gallbladder with direct extension to the liver and adjacent organs (Fig.5). Biliary dilatation is present in close to half of cases. This case presented with diffuse gallbladder wall thickening (Fig.1), a nonspecific finding. Differential diagnosis of diffuse gallbladder wall thickening includes acute and chronic cholecystitis, hepatic disease, hypoalbuminaemia, congestive heart failure, and adjacent inflammatory processes such as perforated duodenal ulcer or pancreatitis, diffuse adenomyomatosis of the gallbladder, and gallbladder carcinoma. In this case, the adjacent lymphadenopathy and mesenteric infiltration (Fig.2) are a clue to the diagnosis of gallbladder carcinoma. References: 1. Levy A, Murakata L, et-al. Gallbladder Carcinoma: Radiologic-Pathologic Correlation RadioGraphics 2001; 21:295–314 2. Furlan A, Ferris J, et-al. Gallbladder Carcinoma Update: Multimodality Imaging Evaluation, Staging, and Treatment Options. American Journal of Roentgenology. 2008;191: 1440-1447 3. Ralls PW, Quinn MF, Juttner HU et-al. Gallbladder wall thickening: patients without intrinsic gallbladder disease. AJR Am J Roentgenol. 1981;137 (1): 65-8. 4. Van breda vriesman AC, Engelbrecht MR, Smithuis RH et-al. Diffuse gallbladder wall thickening: differential diagnosis. AJR Am J Roentgenol. 2007;188 (2): 495-501. Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice serves as the Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances and given as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice to launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. All posts by Kevin M. Rice, MD

New Right Breast Nodule in 62F • Xray of the Week 2016 • Week #29 This 62 year old female presented with a new right breast nodule. Mammogram and ultrasound were done. The patient had an ultrasound guided biopsy of the nodule, and subsequent excision. What rare type of breast cancer could this be? Figure 1. Left 2 images: CC Mammogram, shows a nodule with indistinct margins in the right breast medially. Figure 1. Right 2 images: MLO Mammogram, shows a nodule with indistinct margins in the right breast inferiorly. Figure 2. Left image: Mammogram spot compression view, shows the nodule with indistinct margins in the right breast medially(red arrow). Figure 2. Middle and right images: Ultrasound images show a hypoechoic right breast nodule with angular margin (red arrow), which is also taller than wide. Ultrasound biopsy was performed, followed by excision of the nodule and pathology was medullary breast cancer [Figs.3-4.] Figure 3. Low power view of medullary carcinoma with well circumscribed, "pushing" border. Histology images courtesy of Dennis Kasimian, MD. Chair of Pathology at Valley Presbyterian Hospital - Los Angeles, CA, USA. Figure 4. High power views. A: Syncytial growth of large pleomorphic cells with indistinct cell borders, large vesicular nuclei containing prominent nucleoli and numerous mitoses. B: Characteristic prominent lymphoplasmacytic inflammatory infiltrate at the periphery of the tumor. Histology images courtesy of Dennis Kasimian, MD. Chair of Pathology at Valley Presbyterian Hospital - Los Angeles, CA, USA. Medullary breast cancer is a rare form of breast cancer, comprising less than 2% of all breast tumors (1-3). The cancer tends to occur in younger patients, with a mean age at presentation of 46-54. The masses may be well circumscribed or have ill-defined margins (1-3). MRI is nonspecific usually with an oval or lobular shaped mass and rim enhancement with or without enhancing internal septations (4). Of note, ultrasound with a taller than wide appearance has a positive predictive value (PPV) for malignancy of 81% and angular margin on ultrasound has a PPV of 68% (5). Pathologically, the World Health Organization criteria for diagnosis is “a well circumscribed carcinoma composed of poorly differentiated cells with scant stroma and prominent lymphoid infiltration” (6,7). The classic presentation of medullary carcinoma involves a syncytial growth pattern of poorly-differentiated tumor cells with a high mitotic rate (6,7) [Figs.3-4.]. Syncytial pattern indicates a multinucleated mass of cytoplasm that is not separated into individual cells. (7) Although medullary breast cancer has a better prognosis than invasive ductal carcinoma, the nodules may rapidly enlarge (1-4). Related cases: Invasive Ductal Carcinoma of the Breast in 27 Year Old Phyllodes Tumor References: 1. Harvey JA. Unusual breast cancers: useful clues to expanding the differential diagnosis. Radiology. 2007;242 (3): 683-94. 2. Meyer JE, Amin E, Lindfors KK et-al. Medullary carcinoma of the breast: mammographic and US appearance. Radiology. 1989;170 (1): 79-82. 3. Yoo JL, Woo OH, Kim YK et-al. Can MR Imaging contribute in characterizing well-circumscribed breast carcinomas? Radiographics. 2010;30 (6): 1689-702 4. Jeong SJ, et al. Medullary Carcinoma of the Breast: MRI Findings American Journal of Roentgenology. 2012;198: http://www.ajronline.org/doi/pdf/10.2214/AJR.11.6944 5. Stavros AT, Thickman D, Rapp CL et-al. Solid breast nodules: use of sonography to distinguish between benign and malignant lesions. Radiology. 1995;196 (1): 123-34. 6. Rosen PP. Medullary carcinoma. In: Rosen's breast pathology. Philadelphia, Pa: Lippincott-Raven, 1997; 355–374. 7. Pedersen L, Schiødt T, Holck S, Zedeler K. The prognostic importance of syncytial growth pattern in medullary carcinoma of the breast. APMIS. 1990 Oct;98(10):921-6. Kevin M. Rice, MD is the President of Global Radiology CME Dr. Rice serves as the Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances and as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M. Rice, MD

Frequent palpitations and SOB • Xray of the Week This patient complained of frequent palpitations and shortness of breath. Chest x-ray was performed, and subsequent device examination revealed inability to reliably depolarize the right atrium. Fig. 1 RA lead (red arrow) of dual chamber pacemaker shows a slight curve on the initial post- placement image, and a straight vertical course on the 30 day image. The right ventricular (RV) lead is normally positioned at the RV apex (blue arrow). Images courtesy of my friend and colleague Marcelo Spector, MD. In this case, the lead is floating freely in atrium, resulting in the inability to reliably depolarize the right atrium. This is probably due to placement with not enough "slack" in the lead to allow for motion during inspiration and standing erect. Fig. 2 Dual lead pacemaker. RA lead (red arrow) of dual chamber pacemaker shows a normal "J" curve with the tip in the right atrial appendage. The right ventricular (RV) lead (blue arrow) is normally positioned at the RV apex. Fig 3A. ICD–biventricular pacemaker combination. Frontal view. The shock coils of the ICD lead appear as thickened metallic sections visualized in the superior vena cava (SVC) and RV (blue arrows). The RA lead (red arrow) demonstrates a J-shaped appearance and curves superiorly and anteriorly with the tip in the right atrial appendage. The left ventricular (LV) lead is placed through the coronary sinus into a cardiac vein, usually along the lateral or posterior free wall of the LV (yellow arrow). The LV lead courses inferiorly and laterally on the frontal radiograph and posteriorly on the lateral view. Fig 3B. ICD–biventricular pacemaker combination. Lateral view. The shock coils of the ICD lead appear as thickened metallic sections visualized in the superior vena cava (SVC) and RV (blue arrows). The RA lead (red arrow) demonstrates a J-shaped appearance and curves superiorly and anteriorly with the tip in the right atrial appendage. The left ventricular (LV) lead is placed through the coronary sinus into a cardiac vein, usually along the lateral or posterior free wall of the LV (yellow arrow). The LV lead courses inferiorly and laterally on the frontal radiograph and posteriorly on the lateral view. Fig 4. ICD–biventricular pacemaker combination. Frontal view on another patient. The shock coils of the ICD lead appear as thickened metallic sections visualized in the superior vena cava (SVC) and RV (blue arrows). The RA lead (red arrow) demonstrates a J-shaped appearance and curves superiorly and laterally with the tip in the right atrial appendage. The left ventricular (LV) lead is placed through the coronary sinus into a cardiac vein, along the lateral or posterior free wall of the LV (yellow arrow). The LV lead courses inferiorly and laterally on this frontal radiograph References: 1. Aguilera, AL MD, et al. Radiography of Cardiac Conduction Devices: A Comprehensive Review. RadioGraphics 2011; 31:1669–1682 2. Sigakis CJG, Mathai SK, et. al. Radiographic Review of Current Therapeutic and Monitoring Devices in the Chest. RadioGraphics 2018; 38:1027–1045 3. Brixey AG, Fuss C. Innovative Cardiac Devices on Chest Imaging An Update. J Thorac Imaging 2017;32:343–357 4. Costelloe, CM, MD, et al. Radiography of Pacemakers and Implantable Cardioverter Defibrillators. AJR 2012; 199:1252–1258 Related posts: Bicuspid Aortic Valve and Aortic Stenosis Implanted Cardiac Loop Recorder Cardiac Tamponade Following Coronary Artery Rotational Atherectomy Papillary Fibroelastoma of Aortic Valve Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All posts by Kevin M. Rice, MD

Prior Duodenal Surgery and Jaundice • Xray of the Week 2016 • Week #32 This 54 year old female had prior duodenal surgery and presented with jaundice. What is the diagnosis and treatment? Fig. 1 CT scan. Mass in the porta hepatis region, surgical staples in the duodenum, and biliary dilatation. Bottom right: Severe biliary dilatation also seen on the Percutaneous Transhepatic Cholangiogram (PTC). Note that no contrast enters the duodenum, despite distention with contrast, indicating high grade obstruction. Fig 2. Left: MRI Coronal FSE T2WI demonstrates a mass in the porta hepatis region and biliary dilatation. Right: Severe biliary dilatation seen on the 3D MRCP image. Video showing how I placed a stent in the common bile duct (CBD) and relieved the biliary obstruction. Duodenal Carcinoma is a rare gastrointestinal malignancy, comprising 0.3% of all GI tract cancers. (1,2) Almost always adenocarcinoma, the neoplasm is the most common malignant tumor of the duodenum. Symptoms are nonspecific and include weight loss, abdominal pain, and later in the process jaundice and vomiting due to gastric outlet obstruction. (1,2) As in this case CT shows a mass or asymmetric thickening of the duodenum, with invasion of fat planes, pancreatic and biliary duct dilatation, and vascular encasement. (1) The overall 5 year survival in one study of 89 patients was 25% (4) with improved outcome following radical surgery. If diagnosed late as in this case, there is a very poor prognosis. (4) References: 1. Jayaraman MV, Mayo-Smith WW, Movson JS et-al. CT of the duodenum: an overlooked segment gets its due. Radiographics. 2001;21 Spec No (suppl 1) 2. Markogiannakis H, Theodorou D, Toutouzas KG et-al. Adenocarcinoma of the third and fourth portion of the duodenum: a case report and review of the literature. Cases J. 2008;1 (1): 98. 3. Imaging Features of Benign and Malignant Ampullary and Periampullary Lesions. RadioGraphics 2014; 34:624–641 4. Santoro E, Sacchi M, Scutari F, Carboni F, Graziano F: Primary adenocarcinoma of the duodenum: treatment and survival in 89 patients. Hepatogastroenterology. 1997, 44 (16): 1157-1163. Kevin Rice, MD serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a Member of Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M. Rice, MD

Thoracic Foreign Body • Xray of the Week This patient had a chest Xray for shortness of breath. Is the foreign body a new type of USB drive left in his shirt pocket? Fig. 1 A. CXR. Foreign body overlying the left side of chest. Fig 1 B. Magnification view showing the detail of the foreign body. Fig. 2 Radiograph of the Medtronic Reveal LINQ implantable cardiac loop recorder. Note the morphology of the device is the same as the device implanted in this patient. Image courtesy of Medtronics. Fig. 3. Medtronic Reveal XT implantable cardiac loop recorder compared to the Medtronic Reveal LINQ implantable cardiac loop recorder. Note the Linq is about one tenth the size of the XT. Images courtesy of John Mandrola, MD and Medtronics. Fig 4. Radiograph (A) and picture (B) of 2 types of USB flash drives. Note the two holes in the A plug on the standard USB flash drive. There are no holes in the compact version. Fig 5. Chest radiograph of patient with Medtronic Reveal XT implantable cardiac loop recorder. The implantable cardiac loop recorder is used in patients with recurrent unexplained episodes of palpitations or syncope, for long-term monitoring in patients at risk for or with documented atrial fibrillation, and for risk stratification in patients who have had a myocardial infarction. (1,2,3) The device is implanted subcutaneously in the left parasternal region and stores EKG data automatically in response to a significant arrhythmia. (1,2,3) It is useful either when symptoms are infrequent or when long-term data are required. The internal loop recorder devices are MRI conditional. (1,4,5,6) The electrical data stored in the loop recorder may be erased or corrupted by the strong magnetic field. Therefore, it is essential for the patient's electrophysiologist to download the data prior to any MRI exam. Since all loop recorders contain ferromagnetic components, there may be motion of the device during a scan. Following MRI, artifacts mimicking arrhythmias are frequently seen internal loop recorder data sets (6). References: 1. Medtronic REVEAL LINQ™ LNQ11 Insertable Cardiac Monitor. MRI procedural information Manual. 2. Vikas Shah MD: xrayoftheweek 43: that's not a USB stick...is it? The XRay Doctor Blog 3. Medtronic Website. http://manuals.medtronic.com/manuals/main/en_US/manual/index?findby=brandmodel&model=LNQ11 4. Wong JA, Gula LJ, Skanes AC, et al. Feasibility of Magnetic Resonance Imaging in Patients with an Implantable Loop Recorder. Pacing Clin Electrophyisol 2008; 31(3): 333-337. 5. Hilbert S, Jahnke C, Loebe S, et al. Cardiovascular magnetic resonance imaging in patients with cardiac implantable electronic devices: a device-dependent imaging strategy for improved image quality. Eur Heart J Cardiovasc Imaging. 2018 Sep 1;19(9):1051-1061. doi: 10.1093/ehjci/jex243. 6. Medtronic Reveal Loop Recorder information at MRIsafety.com Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a Member of Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" award for the Most Effective Radiology Educator. Follow Dr. Rice on Twitter @KevinRiceMD All posts by Kevin M. Rice, MD

Incidental Finding on CT Chest • Xray of the Week 2016 • Week #34 What is the clinical significance of this finding? Fig. 1 CT scan demonstrating marked calcification of the aortic valve. The patient later had an aortic valve replacement. Fig. 2 Image from intra-operative trans-esophageal cardiac echo on this patient demonstrating aortic valve stenosis with marked calcification. Bicuspid aortic valve is an uncommon congenital condition, usually due to fusion of 2 of the 3 leaflets of the aortic valve. High pressure across the valve results in calcification. One of the most common causes of aortic stenosis, bicuspid aortic valve may be present in up 2% of the population. [1,2] Visualization of dense calcification of the aortic valve on imaging studies should prompt the reader to think of bicuspid aortic valve and aortic stenosis. [3] Definitive treatment is aortic valve replacement. Due to dilation of the proximal aorta related to high pressures, aortic root replacement is required in 30% of patients undergoing valve replacement. [4] References: 1. Ko SM, Song MG, Hwang HK. Bicuspid aortic valve: spectrum of imaging findings at cardiac MDCT and cardiovascular MRI. AJR Am J Roentgenol. 2012;198 (1): 89-97. 2. Spindola-franco H, Fish BG, Dachman A et-al. Recognition of bicuspid aortic valve by plain film calcification. AJR Am J Roentgenol. 1982;139 (5): 867-72. 3. Chen JJ, Manning MA, Frazier AA et-al. CT angiography of the cardiac valves: normal, diseased, and postoperative appearances. Radiographics. 29 (5): 1393-412. 4. Siu SC, Silversides CK. Bicuspid aortic valve disease. J. Am. Coll. Cardiol. 2010;55 (25): 2789-800. Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a Member of Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All posts by Kevin M. Rice, MD

RLQ Pain in 56M with Ruptured Appendix 15 Years Ago • Xray of the Week 2016 • Week #35 This 56 year old male complained of chronic right lower quadrant pain and tenderness. He had a ruptured appendix 15 years ago, followed by appendectomy. CT guided biopsy was performed. What is the diagnosis? Fig. 1 CT: Fatty mass in the right abdominal mesentery with a thin high attenuation capsule. Pathologic analysis of the biopsy specimen demonstrated fat necrosis, and the patient was treated conservatively. Fig. 2 CT: Fatty mass in the right abdominal mesentery with a thin high attenuation capsule (blue arrow). My biopsy needle (red arrow). Encapsulated fat necrosis is due to necrotic fatty tissue organizing within a thin or thick fibrous capsule (1,2). It may cause pain and tenderness as it can be associated with inflammation and calcification (3). Since the imaging appearance may be similar with fatty tissue surrounded by a weakly enhancing capsule, and mild mass effect on adjacent structures (Fig. 2 blue arrows), the main concern in the differential diagnosis is liposarcoma (4-6). However, unlike liposarcoma, fat necrosis does not invade adjacent structures. As in this case, the history of prior surgery in the vicinity gives a clue to the correct diagnosis, as patients with encapsulated fat necrosis usually have a history of surgery (1,2). In addition, encapsulated fat necrosis remains stable or becomes smaller over time, whereas liposarcomas usually enlarge. The condition is considered a type of intraperitoneal focal fat infarction (7) along with omental infarction and epiploic appendagitis. As I did in this case, biopsy (Fig. 2 red arrow) can be performed to be certain of the diagnosis. References: 1. Kamaya A, Federle MP, Desser TS. Imaging manifestations of abdominal fat necrosis and its mimics. Radiographics 2011. 31 (7): 2021-34. 2. Chan LP, Gee R, Keogh C, Munk PL. Imaging features of fat necrosis. AJR Am J Roentgenol 2003; 181(4):955–959. 3. Kiryu H, Rikihisa W, Furue M. Encapsulated fat necrosis: a clinicopathological study of 8 cases and a literature review. J Cutan Pathol 2000;27(1):19–23. 4. Takao H, Yamahira K, Watanabe T. Encapsulated fat necrosis mimicking abdominal liposarcoma: computed tomography findings. J Comput Assist Tomogr 2004;28(2):193–194. 5. Chen H, Tsang Y, Wu C, Su C, Hsu JC. Perirenal fat necrosis secondary to hemorrhagic pancreatitis, mimicking retroperitoneal liposarcoma: CT manifestation. Abdom Imaging 1996;21(6):546–548. 6. Andaç N, Baltacioglu F, Cimşit NC, Tüney D, Aktan O. Fat necrosis mimicking liposarcoma in a patient with pelvic lipomatosis: CT findings. Clin Imaging 2003;27(2):109–111. 7. Coulier B. Contribution of US and CT for diagnosis of intraperitoneal focal fat infarction (IFFI): a pictorial review. JBR-BTR. 2010;93 (4): 171-85. Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice serves as the Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances and given as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" award for the Most Effective Radiology Educator. Follow Dr. Rice on Twitter @KevinRiceMD All posts by Kevin M. Rice, MD

Headache and Frontal Mass • Xray of the Week 2016 • Week #36 16 year old male with headache and right frontal palpable mass. What is the diagnosis? What is the eponymous name for the condition at the site of the blue arrow? Figure 1. A: CT axial image. Large osseous defect of posterior wall of the right frontal sinus and a small region of lysis in the anterior right frontal sinus. Figure 1. B: MRI- T1 weighted axial with contrast. Mild right frontal dural enhancement adjacent to the peripherally enhancing abscess in the right frontal sinus/epidural space. Enhancement of the edematous frontal scalp indicates Pott puffy tumor. Figure 1. C: MRI- T2 weighted axial. Abscess in the right frontal sinus/epidural space. Figure 1. D: MRI- T1 sagittal with contrast. Mild right frontal dural enhancement adjacent to the peripherally enhancing abscess in the right frontal sinus/epidural space. Figure 1. E: MRI- Diffusion weighted axial image. Restricted diffusion centered in the right frontal sinus. Figure 1. F: MRI- ADC map axial image. Confirms restricted diffusion centered in the right frontal sinus due to abscess. In 1760, English surgeon Sir Percival Pott, described the condition of frontal sinusitis with subperiosteal abscess and osteomyelitis. Inflammatory extension into the scalp soft tissues results in the non-neoplastic "tumor" in the frontal region. Most commonly seen in adolescents, this is now a rare complication of sinusitis due to early treatment with antibiotics. Of note, Sir Pott also first described arthritic tuberculosis of the spine, now known as Pott disease. As seen in this case, CT scan and MRI demonstrate fluid in the frontal sinus with edema of the adjacent scalp, and a lytic portion of the anterior wall of the sinus. (Fig. 1A) In this case, there is also dural enhancement (Fig. 1D) and an epidural abscess. (Fig. 1B-F) Contrast enhanced CT or MRI may demonstrate other intracranial complications such as, subdural empyema, dural sinus thrombosis, and cerebral abscess. Dural enhancement is seen better on MRI than CT and is indicative of meningitis. A scalp abscess with rim enhancement may also be visualized. The clinical appearance is a frontal palpable erythematous painful mass (Fig. 2). Surgical treatment is required with drainage of the abscess and 6 weeks of IV antibiotics. Figure 2: Tweet from @CMAJ showing the clinical appearance of Pott Puffy Tumor. References: 1. Masterson L, Leong P. Pott's puffy tumour: a forgotten complication of frontal sinus disease. Oral Maxillofac Surg. 2009 Jun;13(2):115-7. 2. Karaman E, Hacizade Y, Isildak H et-al. Pott's puffy tumor. J Craniofac Surg. 2008;19 (6): 1694-7. 3. Durur-subasi I, Kantarci M, Karakaya A et-al. Pott's puffy tumor: multidetector computed tomography findings. J Craniofac Surg. 2008;19 (6): 1697-9. 4. Morón FE, Morriss MC, Jones JJ et-al. Lumps and bumps on the head in children: use of CT and MR imaging in solving the clinical diagnostic dilemma. Radiographics. 24 (6): 1655-74. Kevin M. Rice, MD serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M Rice, MD

"Found Down" • Xray of the Week 2016 • Week #37 This 53 year old male known abuser of oxycodone was found down. Urine was positive for opiates and benzodiazepines. Arterial blood gas results: pH 6.89 (N = 7.38 - 7.42), pCO2 126 mmHg (N = 38 - 42), pO2 19 mmHg (N = 75 - 100), O2 sat 24% (N = 94 - 100) What are the arrows pointing to? Why this appearance? Figure 1: CT Scan of the brain. A & B. high attenuation in the basal cisterns and subarachnoid spaces. C. Diffuse edema with loss of grey and white matter differentiation. The history compatible with anoxic brain injury and the diffuse cerebral edema on the CT scan should indicate that the findings are not due to subarachnoid hemorrhage (SAH). The increased attenuation in the basal cisterns and subarachnoid spaces is due to diffuse cerebral edema related to anoxic encephalopathy. The high attenuation appearance may be due to a combination of diffuse decreased attenuation of the brain as a result of edema, and the subarachnoid space with less low attenuation CSF and a larger proportion of meninges and blood vessels than usual. Differential diagnosis of pseudo-subarachnoid hemorrhage on CT: •Meningitis •Leptomeningeal carcinomatosis •Artifacts on CT: anoxic encephalopathy, Spontaneous intracranial hypotension •Iatrogenic causes: recently administered intrathecal or IV contrast material; and following endovascular procedures such as aneurysm coiling and stroke intervention. Highly proteinaceous material in the subarachnoid space causes increased attenuation which may be due to purulent fluid seen with meningitis or leptomeningeal carcinomatosis, mimicking SAH. Anoxic encephalopathy and spontaneous intracranial hypotension both cause a perceptual error due to relatively higher attenuation of the basal cisterns related to the low attenuation seen with these conditions. Iodinated contrast in the subarachnoid space either due to IV or intrathecal administration causes high attenuation in the subarachnoid space which should be easily differentiated from SAH if the history is known. Likewise, endovascular procedures may result in leakage of iodinated contrast which could be confused with SAH, especially given that the procedures are often done for patients with SAH or aneurysms. Follow up CT scan within 3-4 hours after the procedure will show clearing of the contrast, whereas SAH will persist. References: 1. Carrie P. Marder, et al. Subarachnoid Hemorrhage: Beyond Aneurysms. American Journal of Roentgenology. 2014;202: 25-37. 10.2214/AJR.12.9749 2. Mendelsohn DB, Moss ML, Chason DP, Muphree S, Casey S. Acute purulent leptomeningitis mimicking subarachnoid hemorrhage on CT. J Comput Assist Tomogr 1994; 18:126–128 3. Tsuchiya K, Katase S, Yoshino A, Hachiya J. FLAIR MR imaging for diagnosing intracranial meningeal carcinomatosis. AJR 2001; 176:1585–1588 4. al-Yamany M, Deck J, Bernstein M. Pseudo-subarachnoid hemorrhage: a rare neuroimaging pitfall. Can J Neurol Sci 1999; 26:57–59 5. Given CA, Burdette JH, Elster AD et-al. Pseudo-subarachnoid hemorrhage: a potential imaging pitfall associated with diffuse cerebral edema. AJNR Am J Neuroradiol. 2003;24 (2): 254-6. AJNR Am J Neuroradiol (full text) 6. Yuzawa H, Higano S, Mugikura S et-al. Pseudo-subarachnoid hemorrhage found in patients with postresuscitation encephalopathy: characteristics of CT findings and clinical importance. AJNR Am J Neuroradiol. 2008;29 (8): 1544-9. 7. Zhang J1, Li Q1, Zhang Z2, Sun X1. Pseudo-subarachnoid hemorrhage in a patient with hypoxic encephalopathy. Neurochirurgie. 2015 Feb;61(1):35-7. Kevin Rice, MD serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M Rice, MD

Screening OB Ultrasound • Xray of the Week 2016 • Week #40 This 26 year old had a routine OB ultrasound. What is the abnormality? What is the treatment? Figure 1: Gastroschisis on prenatal ultrasound. Note the herniated small bowel to the right of the cord insertion. The bowel is freely floating in the amniotic fluid. Gastroschisis is a sporadic congenital anomaly characterized by herniation of fetal abdominal contents, usually small bowel, and occasionally stomach, colon and/or liver into the amniotic cavity through a para-umbilical abdominal wall defect. The incidence is approximately 1 per 10,000 live births. With the defect almost always on the right side and typically 2-4 cm long, unlike omphalocele, there is no covering membrane. Associated anomalies (usually malrotation) are seen only in 10% of cases; however, omphalocele has associated anomalies in 27-91% of cases. Figure 2: Omphalocele. The cord inserts at the apex of the abdominal wall defect and the abdominal contents are covered by a membrane. Case courtesy of Dr Ahmed Mahrous Saied, Radiopaedia.org. From the case https://radiopaedia.org/cases/34001 On prenatal ultrasound, the fetal abdominal circumference is small for gestational age due to the herniated abdominal contents. The small bowel is seen to be free floating in the amnionic fluid to the right of the umbilical cord insertion [Figure 1]. With omphalocele, the cord inserts at the apex of the abdominal wall defect and the herniated abdominal contents are covered by a membrane [Figure 2]. Most infants with gastroschisis are treated surgically on the first day of life, however, 90% of cases require multiple operations. The prognosis is good with a survival rate of greater than 90%. References: 1. Morrow RJ, Whittle MJ, McNay MB, Raine PA, Gibson AA, Crossley J (1993). "Prenatal diagnosis and management of anterior abdominal wall defects in the west of Scotland". Prenat Diagn. 13(2): 111–5. 2. Shaw, Anthony (1975). "The myth of gastroschisis". Journal of Pediatric Surgery. 10 (2): 235–44. 3. Devries, Pieter A. (1980). "The pathogenesis of gastroschisis and omphalocele". Journal of Pediatric Surgery. 15 (3): 245–51. 4. Santiago-Munoz PC, McIntire DD, Barber RG, Megison SM, Twickler DM, Dashe JS (2007)."Outcomes of pregnancies with fetal gastroschisis". Obstet Gynecol. 110 (3): 663–8. 5. Baerg J, Kaban G, Tonita J, Pahwa P, Reid D (2003). "Gastroschisis: A sixteen-year review". J Pediatr Surg. 38 (5): 771–4. 6. http://www.cdc.gov/ncbddd/birthdefects/gastroschisis.html 7. Blazer S, Zimmer EZ, Gover A et-al. Fetal omphalocele detected early in pregnancy: associated anomalies and outcomes. Radiology. 2004;232 (1): 191-5. 8. Durfee SM, Downard CD, Benson CB et-al. Postnatal outcome of fetuses with the prenatal diagnosis of gastroschisis. J Ultrasound Med. 2002;21 (3): 269-74. 9. Giulian, BB. Prenatal Ultrasonographic Diagnosis of Fetal Gastroschisis. Radiology 129:473-475, November 1978 10. Daltro P, Fricke BL, Kline-fath BM et-al. Prenatal MRI of congenital abdominal and chest wall defects. AJR Am J Roentgenol. 2005;184 (3): 1010-6. Kevin Rice, MD serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a Member of Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M Rice, MD

Screening OB Ultrasound • Xray of the Week 2016 • Week #39 This 28 year old had a routine OB ultrasound. What is the abnormality? What is the significance of this finding? Fig 1A: Prenatal ultrasound. Coronal head. Absence of the calvarium and brain with associated bulging orbits giving the "frog eye" appearance. Fig 1B: Prenatal ultrasound. Sagittal head and neck. Absence of the calvarium and brain. Anencephaly is the most severe neural tube defect (NTD) with complete absence of most of the cranium, meninges, and calvarium due to failure of closure of the rostral neural tube. All women of child-bearing age should consume 0.4 mg of folic acid daily, especially those attempting to conceive or who may possibly conceive, as this can reduce the risk of anencephaly from 0.1 % to 0.03%. Genetics may play a role in the cause of anencephaly as women with a prior pregnancy with NTD have a 3% risk of having another child with a NTD. Other possible factors include insulin-dependent diabetes, exposure to anticonvulsants, and toxins such as lead, chromium, mercury, and nickel. Antenatal screening for NTD’s with ultrasound and maternal serum alpha-fetoprotein is essentially 100% effective. With ultrasound, no brain parenchymal tissue is seen above the orbits and the calvarium is largely absent. As in this case, coronal ultrasound of the head demonstrates absence of the calvarium and brain with associated bulging orbits giving the "frog eye" appearance. [Fig.1A] Associated findings on ultrasound may include: other neural tube defects such as spina bifida, congenital heart defects, cleft lip/palate, diaphragmatic hernia, spinal dysraphism, clubfoot, omphalocele, and urinary tract anomalies such as hydronephrosis. Prognosis is dismal with 100% fatality, most within the first few hours after delivery. References: 1. Cameron M, Moran P. Prenatal screening and diagnosis of neural tube defects. Prenat Diagn. 2009 Apr;29(4):402-11 2. Goldstein RB, Filly RA. Prenatal diagnosis of anencephaly: spectrum of sonographic appearances and distinction from the amniotic band syndrome. AJR Am J Roentgenol. 1988;151 (3): 547-50. 3. Morbidity and Mortality Weekly Report (MMWR). Effectiveness in Disease and Injury Prevention Use of Folic Acid for Prevention of Spina Bifida and Other Neural Tube Defects -- 1983-1991 http://www.cdc.gov/mmwr/preview/mmwrhtml/00014915.htm 4. Timor-tritsch IE, Greenebaum E, Monteagudo A et-al. Exencephaly-anencephaly sequence: proof by ultrasound imaging and amniotic fluid cytology. J Matern Fetal Med. 5 (4): 182-5. Kevin Rice, MD serves as the Medical Director of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a Member of Renaissance Imaging Medical Associates. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015 Dr. Rice launched Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. Follow Dr. Rice on Twitter @KevinRiceMD All Posts by Kevin M Rice, MD