76 yo M acute right side weakness • Xray of the Week Figure 1. What is the diagnosis? Figure 2. A. T1 weighted image. Note the hyperintense nodules and masses with surrounding edema (red arrows). There is mass effect with narrowing of the left lateral ventricle and third ventricle, as well as rightward midline shift. B. T1 weighted image with contrast. Hyperintense nodules and masses with surrounding edema which also demonstrate contrast enhancement (yellow arrows) and large hemorrhagic lesion in left frontal lobe (green arrow) with hematocrit level compatible with hemorrhage. C. FLAIR image showing large hemorrhagic lesion in left frontal lobe with hematocrit level (green arrow). Discussion: Melanomas are skin cancers that develop in melanocytes, which are derived from the neural crest and produce melanin (1). If sufficient melanin is present in a melanoma, it can appear on T1-weighted magnetic resonance imaging as high signal intensity (1). Melanomas can metastasize to the regional lymph nodes, but hematogenous spread to other organs is most common in advanced stages (1). Advanced melanoma is commonly associated with brain metastases. Nearly 20% of patients have brain metastasis at time of diagnosis of metastatic melanoma while over 50% of patients develop brain metastasis after diagnosis (2). Intracranial melanoma metastases (IMM) can be classified as melanotic with more than 10% melanotic cells or amelanotic with less than 10% melanotic cells (3). They also commonly present with large hemorrhagic lesions as seen in this case. Most intracranial lesions are hypointense on T1-weighted images, but high signal intensity can occur with various substances including gadolinium contrast, intra- and extra-cellular methemoglobin, fat, proteins, minerals such as manganese copper and calcium, and melanin (4,5). The unique T-1 hyperintensity on MR can help in narrowing the differential diagnosis. Melanin pigment has stable free radicals which are paramagnetic and cause shortening of T1 and T2 relaxation times (3,6). Chelated metal ions in melanin and unpaired electrons in free radicals can also cause dipole-dipole interactions and proton relaxation enhancement (3,6). On MRI, melanotic IMM appears as hyperintense relative to the cortex in T1-weighted images due to melanin pigment and hemorrhage, as in this case. Contrast enhancement demonstrates a peripheral rim or diffusely heterogeneous pattern (3). Hypointensity can be seen on T2-weighted images and isointensity or hyperintensity can be seen on proton density-weighted images (3). Amelanotic melanomas show hypointensity or isointensity relative to the cortex on T1 and hyperintensity or isointensity on T2 (3). On CT, IMM can present as single or multiple nodules with increased attenuation and frequent ring-enhancement (5,7). Optical Coherence Tomography (OCT) can also be used to identify intracortical melanomas intraoperatively. This technique is similar to ultrasound B-imaging but it uses reflections of infrared light instead of sound (7). Increased optical backscatter suggests the presence of the tumor in this method (7). Prognosis of IMM is poor, and treatment is controversial (7-9). Current options include surgical resection, stereotactic radiosurgery, whole brain radiation therapy, and immune checkpoint inhibitors, but varying combinations of these methods are typically used (8,9). ​​​​ References: 1. Patnana M, et al. Multimethod Imaging, Staging, and Spectrum of Manifestations of Metastatic Melanoma. Clinical Radiology, vol. 66, no. 3, Mar. 2011, pp. 224–36. doi:10.1016/j.crad.2010.10.014 2. Vosoughi Elham, et al. Survival and Clinical Outcomes of Patients with Melanoma Brain Metastasis in the Era of Checkpoint Inhibitors and Targeted Therapies. BMC Cancer, vol. 18, no. 1, Apr. 2018, p. 490. BioMed Central, doi:10.1186/s12885-018-4374-x 3. Isiklar I, et al. Intracranial Metastatic Melanoma: Correlation between MR Imaging Characteristics and Melanin Content. American Journal of Roentgenology, vol. 165, no. 6, Dec. 1995, pp. 1503–12. doi:10.2214/ajr.165.6.7484597 4. Cakirer S, et al. Spontaneously T1-Hyperintense Lesions of the Brain on MRI: A Pictorial Review. Current Problems in Diagnostic Radiology, vol. 32, no. 5, Oct. 2003, pp. 194–217. PubMed, doi:10.1016/s0363-0188(03)00026-4 5. Zimny A, et al. Intracranial Lesions with High Signal Intensity on T1-Weighted MR Images – Review of Pathologies. Polish Journal of Radiology, vol. 78, no. 4, 2013, pp. 36–46. PubMed: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3908506/ 6. Ma, Mian, et al. Neurocutaneous Melanosis in an Adult Patient with Intracranial Primary Malignant Melanoma: Case Report and Review of the Literature. World Neurosurgery, vol. 114, June 2018, pp. 76–83. ScienceDirect. doi:10.1016/j.wneu.2018.02.007 7. Goulart CR, et al. Cerebral Melanoma Metastases: A Critical Review on Diagnostic Methods and Therapeutic Options. ISRN Surgery, vol. 2011, 2011. doi:10.5402/2011/276908 8. Ma YF, et al. Intracranial Malignant Melanoma: A Report of 7 Cases. Oncology Letters, vol. 10, no. 4, Oct. 2015, pp. 2171–75. PubMed Central, doi:10.3892/ol.2015.3537 9. Goyal S, et al. The Clinical Management of Multiple Melanoma Brain Metastases: A Systematic Review. JAMA Oncology, vol. 1, no. 5, Aug. 2015, pp. 668–76. doi:10.1001/jamaoncol.2015.1206 Amara Ahmed is a medical student at the Florida State University College of Medicine. She serves on the executive board of the American Medical Women’s Association and Humanities and Medicine. She is also an editor of HEAL: Humanism Evolving through Arts and Literature, a creative arts journal at the medical school. Prior to attending medical school, she graduated summa cum laude from the Honors Medical Scholars program at Florida State University where she completed her undergraduate studies in exercise physiology, biology, and chemistry. In her free time, she enjoys reading, writing, and spending time with family and friends. Follow Amara Ahmed on Twitter @Amara_S98 All posts by Amara Ahmed Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

70F with abdominal pain • Xray of the Week Figure 1. Describe the abdominal findings. Figure 2. A. Axial CT scan of the abdomen demonstrating small bowel obstruction secondary to umbilical hernia with collapsed small bowel distal to obstruction (yellow arrow). B. Axial CT abdomen demonstrating dilated small bowel in C shape configuration (green arrow). C. Sagittal CT abdomen demonstrating umbilical hernia outpouching from the abdominal wall. Outline of the hernia follows a C-configuration with small bowel contained within the hernial sac with inflammatory changes (blue arrow). Discussion: An abdominal wall hernia occurs when a portion of the bowel or peritoneum extends beyond the abdominal wall, resulting in a sac containing tissue or abdominal organs. Hernias can be classified as inguinal, femoral, incisional, umbilical, or epigastric (1). The most common ventral hernia is the umbilical hernia (3). An umbilical hernia occurs due to a defect in the anterior abdominal wall 3 cm above or below the umbilicus, as seen in Figure 1 (2). This abdominal defect is common among patients with increased intra-abdominal pressure due to pregnancy, ascites, or obesity, which weakens the abdominal musculature (2). Common complications of abdominal wall hernias include small bowel obstruction (SBO) and bowel ischemia (3,4). An SBO is defined as a complete or partial blockage of the small intestine due to a functional or mechanical pathology as seen in Figure 1. This presents as abdominal pain, distension, nausea, vomiting, constipation, and high-pitched or absent bowel sounds. Further complications include hernia incarceration (irreducible sac) and strangulation (ischemia secondary to lack of blood supply) (3). The use of CT imaging helps identify subtle signs of complications such as obstruction, incarceration, and strangulation (4). On CT imaging, key findings of an SBO include small bowel dilation, a transition point from dilated to nondilated small bowel, colon compression, and air-fluid levels (3, 5). In Figure 1, CT imaging demonstrates the umbilical hernia containing a portion of the small bowel in a C-shaped configuration. Narrowing of the hernial sac neck in addition to fat stranding on CT imaging also suggests hernia incarceration and inflammatory changes (3). Other associated findings of SBO secondary to a strangulated umbilical hernia include discrete mesenteric engorgement, ascitic fluid within the hernia sac, and dilation of herniated bowel loops (3). If asymptomatic, abdominal wall hernias are typically not operated on. If complications arise, surgical treatment with laparoscopic repair or mesh is indicated (3, 4). ​​​​ References: Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Hernias: Overview. 2016 Sep 21 [Updated 2020 Jan 30]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK395554/ Coste AH, Jaafar S, Parmely JD. Umbilical Hernia. [Updated 2020 Jun 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459312/ Aguirre DA, Santosa AC, Casola G, Sirlin CB. Abdominal wall hernias: imaging features, complications, and diagnostic pitfalls at multi-detector row CT. Radiographics. 2005;25(6):1501-1520. doi:10.1148/rg.256055018 Baiu I, Hawn MT. Small Bowel Obstruction. JAMA. 2018;319(20):2146. doi:10.1001/jama.2018.5834 Paulson EK, Thompson WM. Review of small-bowel obstruction: the diagnosis and when to worry. Radiology. 2015;275(2):332-342. doi:10.1148/radiol.15131519 Rabab Zaidi is an aspiring radiologist and fourth year medical student at the Loyola University Chicago Stritch School of Medicine (SSOM). She currently serves as the Community Support Co-Lead for the Loyola University COVID-19 Response Team and Co-President of the Radiology Interest Group at SSOM. At the Stritch School of Medicine, she has also worked with the Department of Radiation Oncology to study prostate cancer imaging and adaptive radiotherapy techniques, where she learned about the intersection of patient care and radiology. Rabab graduated magna cum laude with a degree in Economics from Loyola University Chicago in 2016. She is further passionate about mentorship, advocacy, and photography. Follow Rabab Zaidi on Twitter @ZaidiRabab All posts by Rabab Zaidi Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

25F with headache • Xray of the Week Figure 1. What is the diagnosis? Figure 2. MRI Brain without contrast. Nodule of intermediate signal intensity in the anterior third ventricle (red arrow). Subtle on MRI due to intermediate signal intensity on all sequences, but definite contour abnormality in anterior third ventricle. There is no hydrocephalus. A. Sagittal T1-weighted image. Isointense nodule in the anterior third ventricle (red arrow). B. Axial FLAIR image. Isointense nodule in the anterior third ventricle (red arrow). C. Coronal T2* image. Nodule in the anterior third ventricle (red arrow) with low to intermediate signal intensity. Figure 3. CT Brain without contrast. Nodule in the anterior third ventricle is well seen on CT due to high protein content of cyst. A. Sagittal CT brain. B. Axial CT brain. C. Coronal CT brain. Discussion: Colloid cysts are epithelial-lined cysts containing gelatinous material such as mucin, old blood, cholesterol, and ions (1). They are typically located in the rostral third ventricle near the foramen of Monroe (1). The etiology is unclear but the cyst is thought to be a remnant of the paraphysis element, respiratory epithelium, ependymal cyst from the diencephalon, or invagination of the neuroepithelium of the lateral ventricle (1). Colloid cysts are benign growths but they can cause symptoms such as headaches, diplopia, memory issues, and vertigo due to obstructive hydrocephalus when they block the the flow of cerebrospinal fluid from the lateral ventricles at the foramen of Monroe (1). This can occur via a ball-valve mechanism, in which mobile colloid cysts attached to the ceiling of the third ventricle via a thin peduncle can block CSF flow causing intermittent obstructive hydrocephalus and positional headache (1). On CT, colloid cysts appear as a round mass with a hyperdense appearance, especially when the cyst contains protein or cholesterol or is highly viscous (Fig. 3) (2,3). They can appear as hypodense or isodense in rare cases (2). In isodense cysts, it may be possible to visualize hyperdense areas in the lesion which represent acute hemorrhage on CT (4). Increased intraventricular pressure and transependymal cerebrospinal fluid leak can lead to periventricular hypodensity or enlarged temporal horns on CT, and calcification and hemorrhage may be seen as well (2). Colloid cysts have variable appearance on MRI depending on the material in the cyst. Protein and cholesterol cysts shorten the T1 relaxation time and tend to be hyperintense on T1-weighted images and hypointense on T2-weighted images (2). Cysts that are hypointense on T2-weighted images may be more difficult to view on FLAIR (5). As seen in this case, isointense cysts can be seen on CT scan but may be difficult to see on MRI (5). A rim of peripheral enhancement representing the cyst capsule may be seen, but this may represent enhancement of stretched septal veins that are adjacent to the cyst (1). MRI may show intracystic fluid levels or homogeneous appearance (5). Treatment options are craniotomy, endoscopic aspiration or resection, stereotactic aspiration, and permanent CSF diversion via shunt (6). Stereotaxic aspiration can be used for cysts that show hypodensity on CT and hyperintensity on T2-weighted sequences (7). Cysts with a hypointense appearance on T2-weighted images are less likely to be suitable for aspiration and may require alternate surgical intervention (5). ​​​​ References: Tenny, Steven, and William Thorell. Colloid Brain Cyst. StatPearls, StatPearls Publishing, 2020. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK470314/ Algin O, Ozmen E, Arslan H. Radiologic manifestations of colloid cysts: a pictorial essay. Can Assoc Radiol J. 2013;64(1):56-60. doi:10.1016/j.carj.2011.12.011 Mamourian, A. C., et al. Colloid cyst of the third ventricle: sometimes more conspicuous on CT than MR. AJNR. American Journal of Neuroradiology, vol. 19, no. 5, May 1998, pp. 875–78. http://www.ajnr.org/content/19/5/875 Hamidi H, Faizi FR, Rasouly N, Hoshang MM. CT and MRI Features of Pediatric-Aged Colloid Cysts: Report of Two Cases. Case Rep Radiol. 2017;2017:2467085. doi:10.1155/2017/2467085 Armao D, Castillo M, Chen H, Kwock L. Colloid cyst of the third ventricle: imaging-pathologic correlation. AJNR Am J Neuroradiol. 2000;21(8):1470-1477. http://www.ajnr.org/content/21/8/1470.long Morgan JP, McGraw SC, Asfora WT. Treatment of colloid cyst of the third ventricle by stereotactic aspiration followed by radiosurgery: Report of four cases. Surg Neurol Int. 2018;9:3. Published 2018 Jan 10. doi:10.4103/sni.sni_180_17 Noukoua C. Obstructive Colloid Cyst of the Third Ventricle. J Belg Soc Radiol. 2017;101(1):20. Published 2017 Apr 25. doi:10.5334/jbr-btr.1306 Amara Ahmed is a medical student at the Florida State University College of Medicine. She serves on the executive board of the American Medical Women’s Association and Humanities and Medicine. She is also an editor of HEAL: Humanism Evolving through Arts and Literature, a creative arts journal at the medical school. Prior to attending medical school, she graduated summa cum laude from the Honors Medical Scholars program at Florida State University where she completed her undergraduate studies in exercise physiology, biology, and chemistry. In her free time, she enjoys reading, writing, and spending time with family and friends. Follow Amara Ahmed on Twitter @Amara_S98 All posts by Amara Ahmed Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

Why is there air in the aorta? • Xray of the Week Figure 1. A. Axial CT. Note inflated intra-aortic balloon (red arrows). in descending thoracic aorta B. IABP inflated in descending thoracic aorta (red arrow). C. Sagittal CT showing IABP inflated in descending thoracic aorta (red arrow). Figure 2. Frontal chest X-ray showing the intra-aortic balloon inflated in the descending aorta (red arrows). Note the radiopaque marker at the tip (yellow arrow). Figure 3. Diagram demonstrating intra-aortic balloon inflated in diastole and deflated in systole. Image from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3177429/ (Ref.5) Figure 4. Video of IABP function. Discussion: The intra-aortic balloon pump (IABP) is a cardiac assist device. It is used to stabilize patients with hypoperfusion due to acute congestive heart failure, acute mitral regurgitation, myocardial infarction, or low cardiac output after coronary artery bypass grafting surgery (1). It can also be used as prophylaxis in high risk percutaneous coronary intervention (1). The IABP has a polyethylene or polyurethane balloon at the distal tip of a large bore catheter connected to a console that inflates the balloon with helium (2). The catheter is inserted into the aorta through the femoral artery and the balloon sits in the aorta, 2.5 cm from the left subclavian artery (3). During diastole, the balloon appears radiolucent structure in the descending thoracic aorta (Figs. 1,2). The tip is marked by a linear metallic density on imaging (Fig. 2) (3). The intra-aortic balloon uses counterpulsation to inflate and deflate. It inflates in diastole during aortic valve closure, which increases blood flow to the coronary arteries through retrograde flow (4). It deflates at onset of ventricular systole to increase the cardiac output by decreasing afterload (Fig. 4) (1,4). Overall, the IABP reduces left ventricular wall stress and reduces myocardial oxygen demand while improving stroke volume (4). Contraindications to IABP include uncontrolled sepsis, uncontrolled bleeding diathesis, moderate to severe aortic regurgitation, aortic aneurysm, aortic dissection, or severe peripheral artery disease that has not been pretreated with stenting (1,4). Balloon entrapment and rupture can occur, resulting in gas embolus (4). Improper positioning of the IABP can cause cerebral or renal compromise (4). ​​​​ References: Khan, Tahir M., and Abdul H. Siddiqui. “Intra-Aortic Balloon Pump (IABP).” StatPearls, StatPearls Publishing, 2020. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK542233/ Francolini, I., and A. Piozzi. “12 - Antimicrobial Polyurethanes for Intravascular Medical Devices.” Advances in Polyurethane Biomaterials, edited by Stuart L. Cooper and Jianjun Guan, Woodhead Publishing, 2016, pp. 349–85. ScienceDirect, doi:10.1016/B978-0-08-100614-6.00012-3 Dipoce, J., et al. “Radiology of Cardiac Devices and Their Complications.” The British Journal of Radiology, vol. 88, no. 1046, Feb. 2015. PubMed Central, doi:10.1259/bjr.20140540 Krishna, Murli, and Kai Zacharowski. “Principles of Intra-Aortic Balloon Pump Counterpulsation.” Continuing Education in Anaesthesia Critical Care & Pain, vol. 9, no. 1, Feb. 2009, pp. 24–28. academic.oup.com, doi:10.1093/bjaceaccp/mkn051 Ginat D, Massey HT, Bhatt S, Dogra VS. Imaging of mechanical cardiac assist devices. J Clin Imaging Sci. 2011;1:21. doi:10.4103/2156-7514.80373 Amara Ahmed is a medical student at the Florida State University College of Medicine. She serves on the executive board of the American Medical Women’s Association and Humanities and Medicine. She is also an editor of HEAL: Humanism Evolving through Arts and Literature, a creative arts journal at the medical school. Prior to attending medical school, she graduated summa cum laude from the Honors Medical Scholars program at Florida State University where she completed her undergraduate studies in exercise physiology, biology, and chemistry. In her free time, she enjoys reading, writing, and spending time with family and friends. Follow Amara Ahmed on Twitter @Amara_S98 All posts by Amara Ahmed Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

Diabetes and urosepsis. What procedure is indicated? • Xray of the Week Figure 1. Axial CT image of the abdomen with contrast shows right renal abscess with ring enhancement around the fluid collection. Figure 2. Axial CT images of the abdomen with contrast highlighting right renal abscess with subsequent drainage. A. Right renal abscess (white arrow) with ring of hyperdensity surrounding the fluid collection. B. Percutaneous access needle entering the renal abscess (white arrow). C. Insertion of drainage catheter into the abscess (white arrow). D. Drainage catheter coiled in the abscess (white arrow). Discussion: Renal abscesses are collections of walled-off, infected, and purulent fluid in the renal parenchyma that are commonly associated with underlying pyelonephritis. Other factors that predispose patients to formation of renal abscesses include diabetes mellitus and anatomical abnormalities such as vesicoureteral reflux, neurogenic bladder, polycystic kidney disease, and ureteral calculi (1,2). Clinical manifestations of renal abscesses include fever and chills, flank pain with radiation to the abdomen and costovertebral tenderness (1,2,3). Laboratory findings exhibit leukocytosis with elevation of erythrocyte sedimentation rate and C-reactive protein, however this is non-specific. Contrast enhanced CT is useful to evaluate urosepsis and may reveal renal abscess formation (Fig. 1) (4). CT is also helpful in visualizing the renal parenchyma, suppurative changes, and nearby viscera (4,5,6). CT findings of renal abscesses are a focal collection of fluid with a thickened, irregular enhancing wall (Fig. 1) (2). Other findings of renal abscess may include gas within the central fluid, fascial and septal changes, and perinephric fat plane dissipation (2,3). Beyond CT imaging, ultrasound has some usage in identifying renal abscesses. Ultrasound findings show a hypoechoic or cystic mass with lack of vascular flow indicating an infectious process rather than neoplasm (1). Treatment of renal abscesses includes antibiotic therapy and minimally invasive, percutaneous drainage via CT or ultrasound guidance (Fig. 2). The percutaneous approach is favored over surgical drainage due to improved outcomes and reduced morbidity (1). Abscesses less than 5 cm can be treated conservatively with antibiotics and close follow up (1). When larger than 5 cm, renal abscesses should be treated with percutaneous drainage in conjunction with antibiotics (1). ​​​​ References: 1. Siegel JF, Smith A, Moldwin R. Minimally invasive treatment of renal abscess. The Journal of Urology. 1996; 155(1):52-55. https://doi.org/10.1016/S0022-5347(01)66536-46 2. Yen DH, Hu SC, Tsai J, et al. Renal abscess: early diagnosis and treatment. Am J Emerg Med. 1999;17(2):192-197. https://doi.org/10.1016/S0735-6757(99)90060-8 3. Lee BE, Seol HY, Kim TK, Seong EY, Song SH, Lee DW, Lee SB, Kwak IS. Recent clinical overview of renal and perirenal abscesses in 56 consecutive cases. Korean J Intern Med. 2008;23(3):140. https://doi.org/10.3904/kjim.2008.23.3.140 4. Demertzis, J., Menias, C.O. State of the art: imaging of renal infections. Emerg Radiol. 2007; 14, 13–22. https://doi.org/10.1007/s10140-007-0591-3 5. Kawashima A, Sandler CM, Goldman SM, Raval BK, Fishman EK. CT of renal inflammatory disease. Radiographics. 1997;17(4):851-868. https://doi.org/10.1148/radiographics.17.4.9225387 6. Mitreski G, Sutherland T. Radiological diagnosis of perinephric pathology: pictorial essay 2015. Insights Imaging. 2017;8(1):155-169. https://doi.org/10.1007/s13244-016-0536-z Corey Stump is a medical student and aspiring radiologist at the Marian University College of Osteopathic Medicine in Indianapolis, Indiana. Prior to medical school, he graduated summa cum laude from Wittenberg University where he received a B.S. degree in Biology. He is excited to pursue a career in Diagnostic Radiology with interests in medical education. His current project involves a webinar titled “Navigating The Virtual Match; Program Directors Vs Medical Students” through the Academy of Online Radiology Education with other medical students and radiologists around the country in an effort to provide insight on the upcoming residency match. He is passionate about teaching and he hopes to provide a meaningful experience to medical students one day. Follow Corey Stump on Twitter @corey_stump All posts by Corey Stump Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

Why is there contrast in the liver? • Xray of the Week Pt with renal failure and multiple prior hemodialysis catheters resulting in SVC occlusion. Figure 1. CT scan of patient with SVC occlusion. What is the enhancing liver lesion? Figure 2. A. Axial chest CT showing internal mammary vein (orange arrow), azygos vein (blue arrow), small mediastinal collateral veins (white arrow), and chest and abdominal wall collateral veins (yellow arrow) B. Axial CT showing chest and abdominal wall collateral veins (yellow arrow), hepatic capsule and phrenic veins (green arrow) and portal vein in liver (red arrow) C. Axial chest CT showing azygos vein (blue arrow), internal mammary vein (orange arrow), and mediastinal collateral veins (white arrows) D. Chest and abdominal wall collateral veins (yellow arrows), mediastinal collateral veins (white arrows), hepatic capsule and phrenic veins (green arrow) and portal vein in liver (red arrow). Figure 3. Coronal MIP CT image with thisck slab through the anterior and mid chest demonstrates the caval-mammary-phrenic–hepatic capsule–portal collaterals. Complete obstruction of the superior vena cava has resulted in a pseudolesion in segment 4. Figure 4. Diagram illustrating caval-mammary-phrenic-hepatic capsule-portal pathway. From http://dx.doi.org/10.1594/ECR2014/C-1159 Discussion: Superior vena cava (SVC) occlusion has multiple causes including mediastinal neoplasms, central venous catheters, pacemaker wires, aneurysms, trauma, and granulomatous diseases (1). As a result of SVC occlusion, venous drainage is maintained via collateral pathways between the SVC and portal vein (2). Four well-established collateral routes are the azygous-hemiazygous route, internal mammary vein route, thoracic and superficial thoracoabdominal vein route, and the vertebral venous plexus route (1). The patient in this case presents with SVC occlusion due to renal failure and multiple prior hemodialysis catheters. There is caval-mammary-phrenic-hepatic capsule-portal pathway-to segment 4 of the liver. Blood flows from the internal mammary vein to the inferior phrenic vein, which communicates with hepatic capsular veins (3). The hepatic capsular veins then drain into intrahepatic portal tributaries (3). This causes a hypervascular pseudolesion that can be visualized on imaging as a “focal hot spot” or hyperenhancement along the anterior portion of segment 4 of the liver (3). In nuclear studies, a warm spot near the bare area can be observed using Tc sulfur colloid (1). Along the superior aspect of the liver, there may also be focal contrast enhancement with dilation of inferior phrenic veins and hepatic capsular veins (4). Treatment involves addressing the cause of the SVC obstruction (5). Palliative stenting has been suggested as a possible treatment, but thrombosis is a common complication of this procedure (5). ​​​​ References: Rastogi R, Thulkar S, Garg R, Gupta A. Infraphrenic collaterals in malignant superior vena cava obstruction. Clin Imaging. 2007;31(5):321-324. doi:10.1016/j.clinimag.2007.04.031 Vilgrain V, Lagadec M, Ronot M. Pitfalls in liver imaging. Radiology. 2015;278(1):34-51. doi:10.1148/radiol.2015142576 Kapur S, Paik E, Rezaei A, Vu DN. Where there is blood, there is a way: unusual collateral vessels in superior and inferior vena cava obstruction. RadioGraphics. 2010;30(1):67-78. doi:10.1148/rg.301095724 Keraliya AR, Tirumani SH, Shinagare AB, Ramaiya NH. Beyond PET/CT in Hodgkin lymphoma: a comprehensive review of the role of imaging at initial presentation, during follow-up and for assessment of treatment-related complications. Insights Imaging. 2015;6(3):381-392. doi:10.1007/s13244-015-0407-z Marini TJ, Chughtai K, Nuffer Z, Hobbs SK, Kaproth-Joslin K. Blood finds a way: pictorial review of thoracic collateral vessels. Insights Imaging. 2019;10. doi:10.1186/s13244-019-0753-3​ Amara Ahmed is a medical student at the Florida State University College of Medicine. She serves on the executive board of the American Medical Women’s Association and Humanities and Medicine. She is also an editor of HEAL: Humanism Evolving through Arts and Literature, a creative arts journal at the medical school. Prior to attending medical school, she graduated summa cum laude from the Honors Medical Scholars program at Florida State University where she completed her undergraduate studies in exercise physiology, biology, and chemistry. In her free time, she enjoys reading, writing, and spending time with family and friends. Follow Amara Ahmed on Twitter @Amara_S98 All posts by Amara Ahmed Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

Right eye loss of vision • Xray of the Week What is the the name of the right globe abnormality? Figure 1. Phthisis Bulbi on CT and MR Imaging A. Axial CT scan of the orbits demonstrating the phthisis bulbi with dystrophic calcification (yellow arrow). The globe is small and deformed with enophthalmos. B. Coronal CT scan of the orbits demonstrating the phthisis bulbi with dystrophic calcification (yellow arrow). C and D. Axial MRI T1WI and Axial MRI T2WI of the orbits demonstrating the phthisis bulbi. Note the heterogeneous small, shrunken, calcified, deformed and irregularly shaped right globe, with enophthalmos (green arrow). Figure 2. Phthisis bulbi clinical image in a different patient. Ophthalmic Atlas Image by EyeRounds.org, The University of Iowa is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. https://webeye.ophth.uiowa.edu/eyeforum/atlas/pages/cataract-phthisis-bulbi-post-cataract-surgery.html Discussion: Phthisis bulbi (PB) is a term given to an anatomically misshapen and atrophied ocular globe, secondary to severe injury or long-standing pathology. PB develops due to persistent inflammation and the eye becomes visibly disfigured and shrunken. Common etiologies of PB include penetrating trauma, radiation, infection, and tumor. After the inciting trauma or pathology, the affected eye undergoes profound inflammatory sequelae including proliferation of fibrosis and scarring. There are three stages leading to the progression of PB: stage I is atrophia bulbi without shrinkage, II is atrophia bulbi with shrinkage, III is atrophia bulbi with shrinkage and disorganization (phthisis bulbi) (1). Patients can be asymptomatic in initial stages or present with a wide spectrum of pain, irritation and blindness. The most common features of PB include a small-sized asymmetrical affected eye with enophthalmos, corneoscleral scarring, hypotonia, and cataracts (Fig.2). End-stage PB can result in retinal detachment. Intraocular exam will demonstrate extremely low intraocular pressure, sometimes reaching 0 mmHg. (2) On CT imaging the globe will be notably shrunken with increased attenuation in the thickened sclera due to diffuse scarring. Possible ossification and foci of dystrophic calcifications can often be seen and it is difficult to assess normal structures of the eye (Fig. 1). MRI will demonstrate various areas of increased signal depending on the degree of calcification in T1-weighted images. T2-weighted images of PB can show filling defects due to calcifications, and FLAIR sequence will exhibit increased signal in the damaged eye contrasting with the contralateral eye (Fig. 1). (3) In the beginning stages of PB, patients can be given a topical steroid and cycloplegic agent to mild symptomatic relief but PB will continue to progress. Currently, the only permanent treatment for PB involves enucleation of the eye when pain becomes severe. Prosthetic rehabilitation of the affected eye has resulted in good cosmetic outcomes especially following enucleation. (1,2) ​​​​ References: 1. Kaiser PK, Friedman NJ, Pineda R. The Massachusetts Eye and Ear Infirmary Illustrated Manual of Ophthalmology. 4th ed. Saunders; 2014. https://bit.ly/2R7bbYG 2. Dohlman CH, D’Amico DJ. Can an Eye in Phthisis Be Rehabilitated? A Case of Improved Vision With 1-Year Follow-up. Archives of ophthalmology. 1999;117(1):123-124. doi:10.1001/archopht.117.1.123 3. Midyett FA, Mukherji SK. Phthisis bulbi. Orbital Imaging; 2015:29-31. doi:10.1016/B978-0-323-34037-3.00017-3 Nirali Dave is a medical student at Medical University of Lublin in Poland, currently doing clinical rotations in New York. Before that she completed her undergraduate education at Rutgers University, and worked as a medical scribe. Nirali was first exposed to basic radiologic imaging while scribing, and was very quickly taken by the field. Her passion for radiology comes from the bridging of anatomy, health technologies, and patient care. In the future, she hopes to complete a diagnostic radiology residency and stay committed to clinical research and patient education. Follow Nirali Dave on Twitter @ndave08 All posts by Nirali Dave Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

History of arrhythmias • Xray of the Week What is the diagnosis? Figure 1. What is the important finding seen on these CT images? Figure 1A: Axial CT image of abdomen with hyperdense liver Figure 1B: Zoomed-in axial CT image of liver- note the ROI is 154 HU Figure 1C: Zoomed-in axial CT image of spleen- note the ROI is 63 HU Figure 1D: Coronal CT image of abdomen with hyperdense liver Discussion: Amiodarone is an antiarrhythmic agent used to treat ventricular arrhythmias and atrial fibrillation. It is a class III drug, based on the Vaughan Williams classification, and works by prolonging the QT interval (1). The drug can also cause bradycardia, atrioventricular nodal conduction, increased refractoriness, and decreased intracardiac conduction (1). Moreover, since amiodarone is highly lipid soluble, it is stored in high concentrations in the liver, lungs, eyes, thyroid, and skin (1). One study found that all patients undergoing ophthalmologic examinations were found to have asymptomatic corneal microdeposits (2). It was further noted that a rise in hepatic enzyme levels was correlated to dosage and plasma drug and metabolite concentrations (2). Older patients pose a higher risk of developing hypothyroidism and those with abnormal lung functions prior to therapy may be predisposed to pulmonary alveolitis (2). Most of the observed unwanted effects resolve when amiodarone is decreased in dose or discontinued (2). Though it is uncommon, liver toxicity can occur and is manifested by elevated liver transaminase levels (1). Since amiodarone accumulates in lipid reservoirs and is released slowly, the concentration in the liver can be as high as 500-fold of the serum level (3,4). Characteristics of amiodarone-induced hepatotoxicity include histologic steatosis, inflammation, fibrosis, and phospholipidosis (5). On imaging, we can appreciate increased density in the liver on non-contrast CT which is thought to be secondary to increased iodine content from the amiodarone (3,4). Increased liver attenuation on CT is a nonspecific finding and can also be seen with iron deposition in primary hemochromatosis, thalassemia, and hemosiderosis(6). Increased attenuation can also be seen with gold deposition, copper deposition in Wilson disease, and type IV glycogen storage disease (6). In Figure 1A, 1B, and 1D we can visualize the increased density of the liver on CT due to the chronic use of amiodarone. Normally, the liver has a similar density to the spleen on non-contrast CT scans (7), whereas in this case the liver is markedly hyperdense (154 HU) compared to spleen (63 HU). In the initial paper on hepatic Amiodarone deposition, liver hyperdensity measured 95 to 145 HU (Normal is 30-70) (4). Treatment of amiodarone toxicity involves reducing the dosage or discontinuing the usage (2); however, hepatic deposition without toxicity is usually an incidental finding that does not require any treatment. ​​​​ References: Siddoway, L. A. (2003). Amiodarone: guidelines for use and monitoring. American family physician, 68(11), 2189-2196. https://www.aafp.org/afp/2003/1201/p2189.html Harris, L., McKenna, W. J., Rowland, E., & Krikler, D. M. (1983). Side effects and possible contraindications of amiodarone use. American heart journal, 106(4), 916-923. doi:10.1016/0002-8703(83)90016-9 Hussain, N., Bhattacharyya, A., & Prueksaritanond, S. (2013). Amiodarone-induced cirrhosis of liver: what predicts mortality?. Isrn Cardiology, 2013. doi:10.1155/2013/617943 Goldman IS, Winkler ML, Raper SE, et al. Increased hepatic density and phospholipidosis due to amiodarone. AJR Am J Roentgenol. 1985;144(3):541-546. doi:10.2214/ajr.144.3.541 Buggey J, Kappus M, Lagoo AS, Brady CW. Amiodarone-Induced Liver Injury and Cirrhosis. ACG Case Rep J. 2015;2(2):116-118. Published 2015 Jan 16. doi:10.14309/crj.2015.23 Ros P.R. (2018) Imaging of Diffuse and Inflammatory Liver Disease. In: Hodler J., Kubik-Huch R., von Schulthess G. (eds) Diseases of the Abdomen and Pelvis 2018-2021. IDKD Springer Series. Springer, Cham. doi:10.1007/978-3-319-75019-4_22 Herring W. Learning Radiology: Recognizing the Basics. Elsevier; 2015.​ Amer Ahmed is a fourth-year medical student at Midwestern University Chicago College of Osteopathic Medicine. There, he has served as the President for the Medical Business Association and Secretary for the Radiology Interest Group. Before medical school, Amer earned a degree in Economics at Loyola University Chicago and spent some time as an Investment Specialist at Merrill Edge before deciding to pursue his interest in medicine. Radiology intrigued Amer following a back injury requiring him to get an MRI. That is when he was able to appreciate the eye for detail Radiologists possess. Amer is passionate about finance, medicine, and technology. Follow Amer Ahmed on Twitter @amer_ahmed401 All posts by Amer Ahmed Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

32 F with Vaginal Bleeding • Xray of the Week Patient at 25 weeks gestational age. Figure 1. Sagittal transvaginal ultrasound of the cervix. Figure 2. Sagittal transvaginal ultrasound of the cervix. A. Gray scale images show the fetal umbilical cord blood vessels (red arrow) across or near the internal os (orange arrow). B. Color doppler images show the fetal umbilical cord vessels across or near the internal os (yellow arrow). Discussion: Vasa previa is a rare and serious complication of pregnancy in which fetal umbilical cord blood vessels run across or near the internal opening of the cervix (1). Because the vessels run within the membranes, they are unsupported by the umbilical cord, placental tissue, or Wharton jelly (1). This increases risk of vessel rupture when the membranes rupture during labor. There are two types of vasa previa. In type I, there is a velamentous cord insertion between the umbilical cord and the placenta (2). Thus the fetal vessels that run freely within the amniotic membranes run across the cervix or near it (Figs. 1, 2) (2) In type II, fetal vessels run between lobes of succenturiate or bilobate placentas over or near the cervix (1,2). There are several methods used to diagnose vasa previa including identification of placental cord insertion, applying color Doppler over the cervix, 3D ultrasound, and transvaginal ultrasound (3). Linear echolucent structures can be seen over the cervix on gray-scale US (Fig. 2A) (4). These linear echolucent structures can also be seen in marginal sinus previa, which appears as a discontinuous venous lake at the placental margin (1,4). Pulsed Doppler will show a fetal umbilical or venous waveform in vasa previa whereas marginal sinus previa present with flow of a maternal heart frequency (1). Color doppler sonography shows vascular structures over the internal cervical os with a “fixed position during maternal repositioning” (Fig. 2B) (4).Funic presentation (also known as cord presentation) is also commonly confused for vasa previa, but they are different in that the funic presentation demonstrates shifting in position of the cord by tapping the transducer (1). Rupture of the fetal blood vessels can be fatal in vasa previa, so it typically requires elective C-section at 35 weeks (1). Hospitalization with corticosteroids at 32 weeks has also been recommended to promote lung maturity (1). ​​​​ References: 1. Derbala Y, Grochal F, Jeanty P. Vasa previa. J Prenat Med. 2007;1(1):2-13. 2. Sinkey RG, Odibo AO, Dashe JS. #37: Diagnosis and management of vasa previa. American Journal of Obstetrics & Gynecology. 2015;213(5):615-619. doi:10.1016/j.ajog.2015.08.031 3. Marr S, Ashton L, Stemm A, Cincotta R, Chua J, Duncombe G. Vasa praevia: ultrasound diagnosis at the mid‐trimester scan. Australas J Ultrasound Med. 2013;16(1):8-15. doi:10.1002/j.2205-0140.2013.tb00091.x 4. Fadl S, Moshiri M, Fligner CL, Katz DS, Dighe M. Placental imaging: normal appearance with review of pathologic findings. RadioGraphics. 2017;37(3):979-998. doi:10.1148/rg.2017160155 Amara Ahmed is a medical student at the Florida State University College of Medicine. She serves on the executive board of the American Medical Women’s Association and Humanities and Medicine. She is also an editor of HEAL: Humanism Evolving through Arts and Literature, a creative arts journal at the medical school. Prior to attending medical school, she graduated summa cum laude from the Honors Medical Scholars program at Florida State University where she completed her undergraduate studies in exercise physiology, biology, and chemistry. In her free time, she enjoys reading, writing, and spending time with family and friends. Follow Amara Ahmed on Twitter @Amara_S98 All posts by Amara Ahmed Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

41 year old female. COVID-19 positive. SOB • Xray of the Week 41 yo female COVID-19 positive with LLE edema and Shortness of breath. Figure 1. Describe the abnormalities. Figure 2. A. Bilateral lower lobe peripheral ground-glass opacities (GGO) with confluent patchy consolidation (blue arrows). B. Loss of color flow in left popliteal vein (red arrow). C. Thrombosed non-compressible left common femoral vein (red arrow). D. and E. Axial and coronal CT showing partially occlusive left lower lobe pulmonary embolism (orange arrows) Discussion: The SARS-CoV-2 novel virus was first isolated in Wuhan, China. [1,2] In the United States, COVID-19 has been the cause of more than 380,000 deaths as of Jan 12, 2021 [3]. Patients typically present with fever, tachypnea, cough, and sore throat. Severe complications like pulmonary embolism (PE), multiorgan failure, and death can occur [2]. The radiologist plays a vital role in the COVID-19 pandemic due to the importance of imaging in diagnosis and management. The exact pathophysiology and management of this virus is still evolving, however COVID-19 is known to cause a hypercoagulable state with abnormal D-dimer, IL-6, and fibrinogen levels leading to an increased incidence of thrombotic events [1]. In hospitalized COVID-19 patients, the incidence of thrombotic events is between 7.7-49%. Among these, the most commonly occurring thrombotic event is venous thromboembolism [4]. A meta-analysis reported that the incidence of deep vein thrombosis (DVT) patients is 27% and PE is 15% in COVID-19 positive hospitalized patients [5]. If a DVT is suspected, compression ultrasonography of the lower extremity will often show an enlarged, noncompressible vein with corresponding loss of color flow if thrombus is occlusive [6]. The virus’ preferred access to host cells is via angiotensin-converting enzyme 2 (ACE-2) found in the respiratory epithelium. Therefore, the lungs are the most affected organ and visible signs of disease are typically present on imaging [1]. Chest x-rays may demonstrate diffuse ground-glass opacities, however, CT scans are more sensitive for these findings and are considered the first-line imaging modality. CT scans most often demonstrate peripherally distributed ground-glass opacities with reticular and/or interlobular septal thickening, with consolidation [7]. If associated pulmonary embolism is suspected, CT pulmonary angiography will demonstrate a complete or partial filling defect. The “polo mint” sign of partial filling defects is caused by the partial defect surrounded by contrast material [8]. Management of COVID-19 is a work in progress however, hospitalized patients confirmed to have COVID-19 should be on prophylactic anticoagulation unless contraindicated to prevent VTE. Typically low-molecular-weight heparin (LMWH) is preferred for anticoagulation prophylaxis and VTE management but unfractionated heparin can be an alternative, and Fondaparinux can be used in cases of heparin-induced thrombocytopenia (HIT). Tissue plasminogen activator (tPA) can be used as indicated in severe complications of COVID-19 such as limb-threatening DVT or massive PE [9]. ​​​​ References: Connors JM, Levy JH. COVID-19 and its implications for thrombosis and anticoagulation. Blood. 2020;135(23):2033-2040. doi:10.1182/blood.2020006000 Zheng P, Bao L, Yang W, Wang J. Clinical symptoms between severe and non-severe COVID-19 pneumonia: A protocol for systematic review and meta-analysis. Medicine (Baltimore). 2020;99(33):e21618-. doi:10.1097/MD.0000000000021618 Johns Hopkins Coronavirus Resource Center. 2020. Home - Johns Hopkins Coronavirus Resource Center. https://coronavirus.jhu.edu/ [20 October 2020]. Hajra, A., Mathai, S.V., Ball, S. et al. Management of Thrombotic Complications in COVID-19: An Update. Drugs 80, 1553–1562 (2020). doi:10.1007/s40265-020-01377-x Lu Y, Pan L, Zhang W-W, et al. A meta-analysis of the incidence of venous thromboembolic events and impact of anticoagulation on mortality in patients with COVID-19. International journal of infectious diseases. 2020;100:34-41. doi:10.1016/j.ijid.2020.08.023 Karande GY, Hedgire SS, Sanchez Y, et al. Advanced imaging in acute and chronic deep vein thrombosis. Cardiovascular diagnosis and therapy. 2016;6(6):493-507. doi:10.21037/cdt.2016.12.06 Zhao W, Zhong Z, Xie X, Yu Q, Liu J. Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study. American journal of roentgenology (1976). 2020;214(5):1-6. doi:10.2214/ajr.20.22976 Wittram C, Maher MM, Yoo AJ, Kalra MK, Shepard J-AO, McLoud TC. CT Angiography of Pulmonary Embolism: Diagnostic Criteria and Causes of Misdiagnosis. Radiographics. 2004;24(5):1219-1238. doi:10.1148/rg.245045008 Bikdeli B, Madhavan MV, Jimenez D, et al. COVID-19 and Thrombotic or Thromboembolic Disease: Implications for Prevention, Antithrombotic Therapy, and Follow-up. Journal of the American College of Cardiology. 2020;75(23):2950-2973. doi:10.1016/j.jacc.2020.04.031 Nirali Dave is a medical student at Medical University of Lublin in Poland, currently doing clinical rotations in New York. Before that she completed her undergraduate education at Rutgers University, and worked as a medical scribe. Nirali was first exposed to basic radiologic imaging while scribing, and was very quickly taken by the field. Her passion for radiology comes from the bridging of anatomy, health technologies, and patient care. In the future, she hopes to complete a diagnostic radiology residency and stay committed to clinical research and patient education. Follow Nirali Dave on Twitter @ndave08 All posts by Nirali Dave Kevin M. Rice, MD is the president of Global Radiology CME Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. 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

53-year-old female with abdominal pain • Xray of the Week 53-year-old female presented with abdominal pain to the emergency department (ED). A non-contrast CT study was performed in prone position with suspicion of urinary system stone. No stone is appreciated in urinary system and no significant CT finding is found to explain the pain. One month later patient presented with abdominal pain again to the ER. Contrast enhanced CT study ordered for evaluation. Routine postcontrast CT study is performed in supine position. The position of the uterus was different in supine and prone position CT study (Fig 1a-b). Figure 1. a: Sagittal reconstruction of non-contrast (a) and post-contrast CT studies (b) which were performed at one-month intervals demonstrate anteverted position of the uterus in prone (yellow arrow) and retroverted position in supine position (orange arrow). White arrows indicate table position. Discussion: The uterus has a shape similar to an inverted pear. It is divided by body and cervix, and the superior part of the body above the entrance of the tuba uterine known as fundus. The uterus is a muscular organ located between the bladder anteriorly and the rectum posteriorly. It is also a mobile organ, since its position can vary depending on the contents of the bladder and rectum [1]. The tonus of the pelvic floor is the primary support for the uterus. Other ligaments that provide further support to the uterus include the broad ligament, round ligament, ovarian ligament, cardinal ligament, and the uterosacral ligament. The round ligament is composed of fibromuscular connective tissue. It is covered by folded peritoneum and comprises the superior margin of the broad ligament on each side of the uterus [2]. Two round ligaments extend from the uterine horns to the labia majora on each side via the inguinal canal and maintain the anteverted position of the uterus. The most common position of the uterus is anteverted, with the cervix angled forward and anteflexed, and the body flexed anteriorly. A retroverted uterus is a normal variant seen approximately 20% of women where the body of the uterus is tilted posteriorly. There are variable degrees of uterine retroversion. The majority of the time, the retroverted uterus causes no symptoms; however, rarely it may be associated with dyspareunia and dysmenorrhea. This might be because the retroverted position causes the uterus to contact the rectum and posterior wall of the vagina. Mobilization of the uterus during intercourse may generate pain especially if the uterus is fixed in this position. The position of the uterus can also change during pregnancy. However, it is very uncommon for the uterus to switch positions in a normal subject such as seen in this case [3]. The mobility of the uterus can be attributed to the high flexibility of the round ligament. This flexibility might be due to its role in allowing the uterus to grow during pregnancy and adapting to the body’s shape. When a female is not pregnant, the round ligaments that support the uterus are often shorter and firmer. Yet, their flexibility allows them to lengthen, thicken, and stretch during pregnancy. In the images above, we can readily see the difference in the position of the uterus in the prone and supine position. There are no CT findings in this case to explain the abdominal pain and it is uncertain if this uncommon mobility of the uterus is the reason. ​​​​ References: Tullington JE, Blecker N. Lower Genitourinary Trauma. In: StatPearls. Treasure Island (FL): StatPearls Publishing; May 22, 2020. Bookshelf ID: NBK557527 Chaudhry SR, Chaudhry K. Anatomy, Abdomen and Pelvis, Uterus Round Ligament. In: StatPearls. Treasure Island (FL): StatPearls Publishing; August 23, 2020. PMID: 29763145 Bookshelf ID: NBK499970. Sanders RC, Parsons AK. Anteverted retroflexed uterus: a common consequence of cesarean delivery. AJR Am J Roentgenol. 2014;203(1):W117-W124. doi:10.2214/AJR.12.10403. PMID: 24951223. Munevver N. Duran is a pre-medical undergraduate student at Rice University in Houston, Texas, currently double majoring in Kinesiology Sports Medicine and Religious Studies. Munevver was first exposed to radiologic imaging through her research and co-authorship to a review article about the additional diagnostic value of three-dimensional volume rendering imaging in Radiology practice. Her passion for radiology comes from the intersectionality of anatomy and physiology, diagnostic applications, and the continuously improving imaging technologies. In the future, she hopes to become a physician educator with a strong commitment to clinical research and patient-centered healthcare. Ali Morshid is a diagnostic radiology resident at the University of Texas Medical Branch in Galveston, Texas. Ali grew very fond of medical imaging research and academic radiology during his work as a research assistant at MD Anderson Cancer Center and found great satisfaction in preparing didactic sessions and academic presentations for radiology trainees. Ali has multiple publications in peer-reviewed journals in the field of diagnostic radiology and he is working towards a fulfilling career as an academic neuroradiologist.

"Early detection of breast cancer saves lives, one of the great accomplishments of cancer research during the past forty years." - László Tabár​, MD, FACR (Hon) We are honored to have László Tabár one of the world's foremost breast imaging authorities join us at Imaging in England in June, 2018. Dr. László Tabár is a visionary physician, researcher, and educator who has contributed significantly in the worldwide fight against breast cancer. In a career spanning over 40 years, he has worked tirelessly to reduce or eliminate suffering and death from the disease. Through his company, Mammography Education, Inc, he has also been the course director and principal lecturer of more than 300 mammography courses on 6 continents. As a clinician, he has applied his expertise to the interpretation of well over one million mammograms. His pioneering research has laid the foundation for early detection through modern mammographic screening. A consummate educator, Dr. Tabár is responsible for the mentoring of tens of thousands of breast imagers, surgeons and pathologists worldwide. His influence is felt on every continent and there can be no doubt that his work as researcher and educator has saved the lives of hundreds of thousands of women. Dr. Tabár is the recipient of numerous awards including the Terry Fox Award from the British Columbia Medical Association for contributions to cancer research, the Gold Medal from the Society of Breast Imaging, American Cancer Society's Distinguished Service Award, the IMPACT Award for Lifetime Achievement in the Fight Against Breast Cancer by the National Consortium of Breast Care Centers, the Pathfinder Award by the American Society of Breast Disease, and the first Alexander Margulis Award for Scientific Excellence from the Radiological Society of North America (RSNA) in 2012. Click here to see Dr. Tabár's interesting cases on the Global Radiology CME blog