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64-year-old male with sudden onset abdominal pain and lactic acidosis. Diagnosis? • Xray of the Week Figure 1. What are the important findings? Figure 2. A: Axial CT. Gas in the wall of the transverse colon (orange arrow). B: Axial CT- lung window. Gas in the wall of the transverse colon- pneumatosis intestinalis (orange arrow). C: Coronal CT. Gas in the wall of the transverse colon (orange arrow). Gas in the mesenteric portal venous system (red arrow). Gas in the intrahepatic portal venous system (green arrow). D: Coronal CT- lung window. Gas in the wall of the transverse colon- pneumatosis intestinalis. (orange arrow). E: Axial CT. Gas in the intrahepatic portal venous system (green arrow). F: Axial CT- lung window. Gas in the mesenteric portal venous system (red arrow). Discussion: Bowel ischemia is an often fatal condition caused by reduction in blood supply to the bowel and its mesentery. Three possible causes include severe hypotension, atherosclerosis, and thromboembolism which usually manifest as ischemic colitis, chronic mesenteric ischemia (CMI), and acute mesenteric ischemia (AMI), respectively [1]. AMI carries a high mortality rate of approximately 70% with an estimated incidence of 1 to 2 per 1000 hospital admissions [2,3]. Most AMI patients present with sudden onset of abdominal pain that is disproportionate to physical findings, especially with a history of cardiovascular disease. Unfortunately, no laboratory test is sufficiently sensitive or specific to rule in or rule out early bowel ischemia thus imaging and compatible history and physical examination are the cornerstone of early diagnosis [4]. CT angiography is the current standard for diagnosis of AMI with a sensitivity of 96% and specificity of 94%, especially with findings of pneumatosis intestinalis (Fig. 2 orange arrows) and hepatic portal venous gas (Fig. 2 green arrows) as seen in this patient [5]. Furthermore, data suggests combination of pneumatosis intestinalis and hepatic portal venous gas is associated with the presence of bowel ischemia in approximately 70% of all cases indicating advanced stage disease [2,6]. The quantity of hepatic portal venous gas is associated with bowel necrosis, whereas the presence of free air or air-type pneumatosis intestinalis (pneumatosis intestinalis of the entire circumference of the intestine without wall edema) is associated with non-necrosis of the bowel [7]. However, for non-occlusive mesenteric ischemia (NOMI), digital subtraction angiogram is the standard for both diagnosis and treatment. Treatment of mesenteric ischemia is multimodal depending on the etiology. Non surgical treatment may include drug therapy with thrombolysis, heparin, or vasodilators. Interventional radiology rarely may play a role with angioplasty and stenting [8]. However, surgery remains the treatment of choice for patients with acute abdominal pain, peritoneal signs, and suspected AMI as seen in this case [3,9]. Despite treatment mortality remains high ranging between 30 and 90% [9]. ​​​​ References: 1. Dhatt HS, Behr SC, Miracle A, Wang ZJ, Yeh BM. Radiological Evaluation of Bowel Ischemia. Radiol Clin North Am. 2015;53(6):1241-1254. Accessed May 15, 2021. doi:10.1016/j.rcl.2015.06.009. 2. Milone M, Di Minno, Matteo Nicola Dario, Musella M, et al. Computed tomography findings of pneumatosis and portomesenteric venous gas in acute bowel ischemia. World J Gastroenterol. 2013;19(39):6579-6584. Accessed May 15, 2021. doi:10.3748/wjg.v19.i39.6579. 3. Endean ED, Barnes SL, Kwolek CJ, Minion DJ, Schwarcz TH, Mentzer RM. Surgical management of thrombotic acute intestinal ischemia. Ann Surg. 2001;233(6):801-808. Accessed May 15, 2021. doi:10.1097/00000658-200106000-00010. 4. Oldenburg WA, Lau LL, Rodenberg TJ, Edmonds HJ, Burger CD. Acute mesenteric ischemia: a clinical review. Arch Intern Med. 2004;164(10):1054-1062. Accessed May 15, 2021. doi:10.1001/archinte.164.10.1054. 5. van den Heijkant, Teun C., Aerts BAC, Teijink JA, Buurman WA, Luyer MDP. Challenges in diagnosing mesenteric ischemia. World J Gastroenterol. 2013;19(9):1338-1341. Accessed May 15, 2021. doi:10.3748/wjg.v19.i9.1338. 6. Angelelli G, Scardapane A, Memeo M, Stabile Ianora AA, Rotondo A. Acute bowel ischemia: CT findings. Eur J Radiol. 2004;50(1):37-47. Accessed May 15, 2021. doi:10.1016/j.ejrad.2003.11.013. 7. Muratsu A, Muroya T, Yui R, et al. Factors associated with bowel necrosis in patients with hepatic portal venous gas and pneumatosis intestinalis. Acute Med Surg. 2020;7(1):e432. Accessed May 15, 2021. doi:10.1002/ams2.432. 8. Goldberg MF, Kim HS. Treatment of acute superior mesenteric vein thrombosis with percutaneous techniques. AJR Am J Roentgenol. 2003;181(5):1305-1307. doi:10.2214/ajr.181.5.1811305 9. Fitzpatrick LA, Rivers-Bowerman MD, Thipphavong S, Clarke SE, Rowe JA, Costa AF. Pearls, Pitfalls, and Conditions that Mimic Mesenteric Ischemia at CT. Radiographics. 2020;40(2):545-561. doi:10.1148/rg.2020190122 Savan V. Patel is a medical student and aspiring diagnostic radiologist at Rowan University School of Osteopathic Medicine in New Jersey. During his time as a medical student, Savan served as the vice president of Inclusion, Diversity, Equity, and Action (IDEA) council. Prior to medical school, he earned MS in Pharmaceutical Sciences with summa cum laude at Rowan University where he published research on novel compounds composed of cyanopyrrolidines and β-amino alcohol scaffolds tested in vitro against Dipeptidyl Peptidase IV (DPP-IV) enzyme, a key regulator of incretin hormones in the management of type 2 diabetes. He graduated magna cum laude from Rowan University where he completed his studies in biochemistry with a minor in biology. Outside of medical school, Savan loves to travel with his wife, cook new cuisines and listen to Bollywood music. All posts by Savan Patel 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

28 year-old male. Long term intubation 2 months ago secondary to COVID pneumonia. Presents with shortness of breath, difficulty speaking and stridor for the past 2 weeks • Xray of the Week Figure 1. What is the diagnosis? Figure 2. CT scan of the neck and chest demonstrating circumferential hourglass-like narrowing of the trachea (red arrows). Note the normal diameter of the trachea on the axial images proximal (green arrows) and distal (yellow arrows) to the stenosis. Figure 3. Myer Classification of tracheal stenosis (5). Discussion: The most severe complication of COVID-19 has been acute respiratory distress syndrome, which requires oxygen and ventilation therapy for a median of 17 days (1). However, this prolonged intubation also comes with the risk of tracheal stenosis. Post-intubation tracheal stenosis is a rare but serious condition that occurs after long-term intubation. The stenosis occurs when compression from the endotracheal tube (ETT) cuff causes ischemia of the tracheal mucosal tissue, resulting in fibrotic scarring (2). According to Ramalingam et al, tracheal stenosis can also be caused by ETT size relative to the tracheal lumen, ETT material, intubation duration, hemodynamics, tube movement, steroids, and age/sex of the patient (2). It presents as gradual onset dyspnea and dry cough (2). Additional symptoms include shortness of breath, difficulty speaking, and stridor as seen in this patient. Tracheal stenosis can be diagnosed using bronchoscopy (2) or CT scan (3,4). The degree of stenosis can be described using the classification grades established by Myer et al. (Fig. 3) (5). Chest radiography shows focal luminal narrowing with hourglass stenosis about 3-4 cm below the cricoid cartilage (Fig.2) (4). Acute stenosis presents with edema and granulation tissue with concentric soft tissue thickening while chronic stenosis shows focal expiratory airway collapse on dynamic CT (4). Stenosis can usually be prevented by using low pressure cuffs. Treatment includes surgical intervention, bronchoscopic balloon dilation, or laser coblation (2,4). Endoscopic or radiologic guided metallic stent placement has also been used as a first line treatment in cases of simple stenoses. However, it is usually only used if surgery or dilatation are unsuccessful (5). ​​​​ References: 1. Mattioli F, Marchioni A, Andreani A, Cappiello G, Fermi M, Presutti L. Post-intubation tracheal stenosis in COVID-19 patients [published online ahead of print, 2020 Oct 3]. Eur Arch Otorhinolaryngol. 2020;1-2. doi:10.1007/s00405-020-06394-w 2. Ramalingam H, Sharma A, Pathak V, Narayanan B, Rathod DK. Delayed Diagnosis of Postintubation Tracheal Stenosis due to the Coronavirus Disease 2019 Pandemic: A Case Report. A A Pract. 2020;14(8):e01269. doi:10.1213/XAA.0000000000001269 3. Webb EM, Elicker BM, Webb WR. Using CT to diagnose nonneoplastic tracheal abnormalities: appearance of the tracheal wall. AJR Am J Roentgenol. 2000;174(5):1315-1321. doi:10.2214/ajr.174.5.1741315 4. Heidinger BH, Occhipinti M, Eisenberg RL, Bankier AA. Imaging of Large Airways Disorders. AJR Am J Roentgenol. 2015;205(1):41-56. doi:10.2214/AJR.14.13857 5. Myer CM 3rd, O'Connor DM, Cotton RT. Proposed grading system for subglottic stenosis based on endotracheal tube sizes. Ann Otol Rhinol Laryngol. 1994;103(4 Pt 1):319-323. doi:10.1177/000348949410300410 6. Galluccio G, Lucantoni G, Battistoni P, et al. Interventional endoscopy in the management of benign tracheal stenoses: definitive treatment at long-term follow-up. Eur J Cardiothorac Surg. 2009;35(3):429-934. doi:10.1016/j.ejcts.2008.10.041 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

Chronic wrist pain • Xray of the Week This often results from undiagnosed or under treated non-displaced scaphoid fractures. Progressive collapse & deformity usually occur at fracture site, leading to subluxation of midcarpal joint and dorsal rotation of the lunate. Axial CT: Note the remodeling and pseudarthrosis in this case. Coronal CT: Note the remodeling and pseudarthrosis in this case. Phillip Tirman, MD is the Medical Director of Musculoskeletal Imaging at the Renaissance Imaging Center in Westlake Village, California. A nationally recognized expert in the applications of MRI for evaluating MSK and spine disorders, Dr. Tirman is the co-author of three textbooks, including MRI of the Shoulder and Diagnostic Imaging: Orthopedics. He is also the author or co-author on over sixty original scientific articles published in the radiology and orthopedic literature. Dr. Tirman will be sharing his expertise at Imaging in Israel -2017 in Tel Aviv. All Posts by Phillip Tirman, MD

Pain in Medial Knee • Xray of the Week 2016 • Week #43 This 14 year old bent over while showering and felt sudden “pop” with pain in the medial knee. What is the diagnosis? Figure 1. Coronal PD with fat saturation image with red arrow showing the avulsion fragment and donor site. There is surrounding bone marrow edema (green arrows). Sagittal T1 weighted image shows avulsed fragment at attachment of medial gastrocnemius (orange arrow). Figure 2. Axial image shows the avulsed fragment (red arrow). Note the cortical defect indicating a fracture (green arrow). Sagittal T2 “fat sat” image shows 2 mm of distraction (orange arrows). Figure 3. Five weeks after conservative management, there is healing with no physeal bar. Avulsion fracture of the gastrocnemius muscle is a rare injury caused by traction on the origin of the medial head of the muscle on the medial femoral condyle. As in this case, MRI demonstrates a fracture of the medial femoral condyle with mild distraction of the avulsed fracture fragment [Fig. 1-2]. Invariably there is associated bone marrow edema which resolves over time [Fig. 2-3]. A previous case report was of a patient who had an avulsion fracture of the medial head of the gastrocnemius muscle due to a skiing injury. The fracture was successfully treated with open reduction and internal fixation with a screw[1]. A second case of case of a 14-year-old male wrestler presented with a radiographically occult avulsion fracture of the medial gastrocnemius tendon sustained during competition[2]. This was treated conservatively with return to competition after non-operative management. Other more common avulsion fractures of the knee are described in detail by Gottsegen et al [3]. References: 1. Maehara H, Sakaguchi Y. Avulsion Fracture of the Medial Head of the Gastrocnemius Muscle: A Case Report. The Journal of Bone & Joint Surgery. 2004; 86:373-375 2. Patterson, J.T., Jokl, P., Katz, L.D. et al. Isolated avulsion fracture at the medial head of the gastrocnemius muscle. Skeletal Radiol (2014) 43: 1491. doi:10.1007/s00256-014-1915-5 3. Gottsegen C, Eyer B, et al. Avulsion Fractures of the Knee: Imaging Findings and Clinical Significance. RadioGraphics 2008; 28:1755–1770 Phillip Tirman, MD is the Medical Director of Musculoskeletal Imaging at the Renaissance Imaging Center in Westlake Village, California. A nationally recognized expert in the applications of MRI for evaluating MSK and spine disorders, Dr. Tirman is the co-author of three textbooks, including MRI of the Shoulder and Diagnostic Imaging: Orthopedics. He is also the author or co-author on over sixty original scientific articles published in the radiology and orthopedic literature. Kevin Rice, MD is president of Global Radiology CME and also a radiologist with Renaissance Imaging as the Chair of the Radiology Department at Valley Presbyterian Hospital in Los Angeles, California. All posts by Phillip Tirman, MD 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

First toe pain in a professional football player • Xray of the Week First toe pain in a 30 y/o professional football player. What is the diagnosis? Figure 1. Sagittal T1 (A) and "fat sat" (B) images show a tear of the tibial sesamoid phalangeal ligament (red arrow). The tear is a complete tear (grade III) with retraction of the tibial sesamoid. Figure 2. Sagittal “fat sat” images show a normal (green arrow) and a torn (red arrow) sesamoid phalangeal ligament. Figure 3. Axial “fat sat” images show a normal (green arrow) and a torn (red arrow) sesamoid phalangeal ligament. Figure 4. This football player is at high risk for turf toe. Note the hyperextension of the first metatarsal phalangeal joint (insert) and the massive downward pressure by the opposing player. Figure 5. Accelerated arthrosis in a 27 year old with chronic turf toe. Sagittal (A) and coronal (B) images show a shortened scarred sesamoid phalangeal ligament (red arrow) and a chronic osteochondral defect of the first metatarsal head (green arrows). Discussion: Turf toe is a tear of the sesamoid phalangeal ligament [Figs. 1-3]. The mechanism of injury in the acute setting is a hyperextension of the first metatarsal phalangeal joint when the hallux is fixed in equinus [Fig.4]. Chronic tear may occur with hyperextension or repeatedly pushing off when running or jumping. Playing football especially on artificial turf is a predisposing factor. Significant morbidity can occur with up to half of patients still symptomatic at 5 years. Most cases are managed conservatively with ice, elevation, and NSAIDS. Immobilization is used in higher grade injuries. However, surgery may be needed for failed conservative management or if there are complications such as sesamoid fracture, bipartite sesamoid separation, sesamoid proximal migration, instability with pain/synovitis, hallux rigidus, or an unstable chondral flap of the first metatarsal phalangeal joint [Fig.5]. References: 1. McCormick JJ, Anderson RB. The great toe: failed turf toe, chronic turf toe, and complicated sesamoid injuries. Foot Ankle Clin. Jun 2009;14(2):135-50. 2. Crain JM, Phancao JP, Stidham K. MR imaging of turf toe. Magn Reson Imaging Clin N Am. Feb 2008;16(1):93-103, vi. 3. Sanders TG, Rathur SK. Imaging of painful conditions of the hallucal sesamoid complex and plantar capsular structures of the first metatarsophalangeal joint. Radiol Clin North Am. Nov 2008;46(6):1079-92, vii. 4. Yao L, Do HM, Cracchiolo A, et al. Plantar plate of the foot: findings on conventional arthrography and MR imaging. Am J Roentgenol 1994;163:641-4. 5. Kubitz ER. Athletic injuries of the first metatarsophalangeal joint. J Am Podiatr Med Assoc. Jul-Aug 2003;93(4):325-32. 6. Resnick D, Kang HS. Internal derangement of joints: emphasis on MR imaging Philadelphia, Pa: Saunders, 2nd Ed. 2006. Buy it on Amazon 7. Linklater JM. Imaging of Sports Injuries in the Foot. AJR 2012; 199:500–508 8. Stoller D, Tirman P, Bredella M et-al. Diagnostic imaging. AMIRSYS. (2004) ISBN:0721629202. www.amazon.com/gp/product/0721629202 9. Ashman CJ, Klecker RJ, Yu, JS. Forefoot Pain Involving the Metatarsal Region: Differential Diagnosis with MR Imaging. RadioGraphics 2001; 21:1425–1440 10. http://radsource.us/clinic-turf-toe/ 11. Allen LR, Flemming D, Sanders TG. Turf toe: ligamentous injury of the first metatarsophalangeal joint. Mil Med. 2004 Nov;169(11):xix-xxiv. Phillip Tirman, MD is the Medical Director of Musculoskeletal Imaging at the Renaissance Imaging Center in Westlake Village, California. A nationally recognized expert in the applications of MRI for evaluating MSK and spine disorders, Dr. Tirman is the co-author of three textbooks, including Shoulder Magnetic Resonance Imaging and Diagnostic Imaging: Orthopedics. He is also the author or co-author on over sixty original scientific articles published in the radiology and orthopedic literature. In 2018, Dr. Rice was nominated and became a semifinalist for a "Minnie" award for the Most Effective Radiology Educator. All posts by Phillip Tirman, MD 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. 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

Acute Onset Knee Pain • Xray of the Week A 68 year old female presenting with acute onset knee pain following crush injury of knee. What is the diagnosis? Figure 1. Plain radiographs of the knee AP (A), and lateral (B). ​Figure 2. Plain radiographs of the knee AP (A), and lateral (B). Green arrow demonstrating the avulsion fracture fragment due to the ruptured quadriceps tendon. Figure 3. Sagittal ​MRI of the knee. T1 weighted image (A) and T2 weighted image (B). Green arrow demonstrating the ruptured quadriceps tendon with discontinuity and retraction. Discussion: The quadriceps muscle group is the primary extension mechanism of the knee and consists of the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris.[1] The 4 tendons of these muscles insert onto the patella as the quadriceps tendon or sometimes referred to as the quadriceps expansion.The quadriceps tendon is composed of 3 layers:The superficial layer from the rectus femoris, the middle layer composed of the vastus lateralis and medialis, and the deeper layer from the vastus intermedius [1,2]. There is some variability on the anatomic configuration of the layers of the quadriceps tendon.The vastus medialis and vastus lateralis join the superficial and deep layers of the quadriceps tendon in varying proportions as the most common anatomic arrangement [2]. Quadriceps tendon injury may be secondary to repetitive microtrauma, weakening from underlying medical conditions such as gout, diabetes, collagen vascular diseases, chronic renal failure [3,4,5] or from strong deceleration injury. Additional predisposing factors include older age, obesity and steroid use [4]. Traumatic injuries may result in acute partial or complete tears, usually a few centimeters removed from the upper patellar pole [1]. Complete tendon rupture is usually a clinical diagnosis with loss of extensor function [2,4] and MRI is performed more for surgical planning and confirmation of diagnosis whereas in partial tendon ruptures, MRI serves a more critical role in diagnosis [2]. Initial evaluation with acutely injured patients tends to be with radiographs in the emergency department. Associated radiologic findings include suprapatellar mass usually composed of the retracted tendon and associated edema as well as a joint effusion [Figs.1,2] [4]. On lateral radiographs, disruption of the normal quadriceps outline may be identified as well as a soft tissue defect superior to the patella where a corresponding palpable defect may be felt on physical examination [4], similar to our case above [Figs.1,2]. On MRI, partial rupture of the quadriceps tendon usually is manifested by edema and heterogeneity of the quadriceps tendon. With complete rupture of the quadriceps tendon, MRI demonstrates retraction of the torn ends, and surrounding edema, and frequently a joint effusion [Fig.3] [1]. Treatment needs to be prompt and will be determined by degree of injury and rupture. Partial ruptures may be treated conservatively with immobilization, however complete tendon rupture with or without associated patellar fracture need emergent orthopedic evaluation and surgery in order to regain full function and prevent retraction and fibrosis [4]. References: 1. Bencardino JT, Rosenberg ZS, Brown RR, Hassankhani A, Lustrin ES, Beltran J (2000) Traumatic musculotendinous injuries of the knee: diagnosis with MR imaging. Radiographics. 20(suppl1):S103–S120. 2. Zeiss J, Saddemi SR, Ebraheim NA. MR imaging of the quadriceps tendon: normal layered configuration and its importance in cases of tendon rupture. AJR. 1992;159:1031-1034. 3. Kim, Y.H., Shafi, M., Lee, Y.S. et al. Spontaneous and simultaneous rupture of both quadriceps tendons in a patient with chronic renal failure. Knee Surg Sports Traumatol Arthrosc. 2006 Jan;14(1):55-59. 4. Nance EP Jr, Kaye JJ (1982) Injuries of the quadriceps mechanism. Radiology 142:301–307. 5. Bikkina RS, Chaljub G, Singh H, Allen SD. Magnetic resonance imaging of simultaneous bilateral quadriceps tendon rupture in a weightlifter: case report. J Trauma. 2002; 52(3):582-584.5. Alexandra (Sasha) Roudenko, MD is originally from Siberia, Russia and grew up in New York City. After graduating magna cum laude from Barnard College - Columbia University as a chemistry major, she was invited to join the prestigious Phi Beta Kappa Society. She then received her MD degree from New York University School of Medicine. Dr. Roudenko is currently a third year radiology resident at Mount Sinai West - St. Luke's and has developed a passion for body imaging. She is particularly interested in body MRI and plans on pursuing the subspecialty throughout her career. In 2016, Dr. Roudenko was awarded a fellowship in the Introduction to Academic Radiology program at ARRS. All posts by Sasha Roudenko, MD

Acute Onset Lateral Foot Pain • Xray of the Week 63 y.o. male presented with 1 hour of aching pain on the lateral aspect of the right midfoot after he felt a pop while climbing stairs. He had no loss of sensation, stiffness, or swelling, but pain limited his range of motion. Initial x-rays of the right foot and ankle were taken with a follow up right foot MRI. What is the diagnosis? Figure 1. Prior oblique (A), current oblique (B) and current frontal (C) radiographs of the right foot. Figure 2. Prior oblique (A), current oblique (B) and current frontal (C) radiographs of the right foot demonstrate interval migration of an os peroneum from its expected position at the calcaneocuboid joint to the lateral aspect of the calcaneus (red arrows). Figure 3. Prior (A) and current (B) lateral radiographs of the right foot demonstrate interval posterior migration of an os peroneum from its expected position at the calcaneocuboid joint to the lateral anterior aspect of the calcaneus (red arrows). Figure 4. Illustration of the normal peroneus longus tendon viewed from the lateral plantar aspect of the foot. The os peroneum is a small ossicle located within the substance of the peroneus longus tendon at the inferolateral aspect of the base of the cuboid. The peroneus longus tendon passes posterior to the lateral malleolus, then curves anteriorly and obliquely down the lateral side of the foot where it curves forward under the fibular trochlea of the calcaneus. The os Peroneum is present in the substance of the The peroneus longus tendon proximal to cuboid tuberosity/tunnel. The peroneus longus tendon then extends under the foot to insert on the inferolateral aspect of the base of the first metatarsal and the distal end of the medial cuneiform. Illustration by Raf Ratinam, MBBS. Figure 5. Illustration of the ruptured peroneus longus tendon viewed from the lateral plantar aspect of the foot. The os peroneum is retracted due to a complete tear of the peroneus longus tendon at the inferolateral aspect of the base of the cuboid. Illustration by Raf Ratinam, MBBS. Figure 6: GIF. Axial PD MR images of the right foot demonstrating a complete tear of the peroneus longus tendon (red arrow) with approximately 2 cm gap. The os peroneum (labeled) is retracted to the inferior peroneal retinaculum. Note the distal peroneus longus tendon (yellow arrow) continuing through its anatomical course to the first metatarsal base. Figure 7: GIF. Sagittal T1 MR images of the right foot demonstrating a complete tear of the peroneus longus tendon (red arrow) with approximately 2 cm gap. The os peroneum (labeled) is retracted to the inferior peroneal retinaculum. Note the distal peroneus longus tendon (yellow arrow) continuing through its anatomical course to the first metatarsal base. Figure 8: Sagittal T1 MR images of the right foot demonstrating a complete tear of the peroneus longus tendon (red arrow) with approximately 2 cm gap. The os peroneum (labeled) is retracted to the inferior peroneal retinaculum. Discussion The os peroneum is an accessory ossicle found within the substance of the peroneus longus tendon. Normally seen in up to 30% of people, the os peroneum is bipartite approximately 30% of the time, and unilaterally ossified approximately 40% of the time [1-2]. Painful Os Peroneum Syndrome (POPS) is a general term to describe pain that results in an array of conditions, including fracture of the ossicle, partial or complete rupture of the peroneus longus tendon [Figs. 5-7], or diastasis of the bipartite ossicle. Primary tenosynovitis or peroneus longus tendinosis can also be a source of pain in this region[2]. POPS should be considered in patients with pain in the lateral midfoot. Palpation over the ossicle will often elicit pain, although physical exam is frequently variable. POPS may be secondary to trauma in an acute setting; however, the initial injury is often missed and the patient can present with chronic pain[1]. Plain radiographs, MRI, and increasingly ultrasound are useful in the diagnosis of POPS. Os peroneum fragment separation of ≥6mm, or proximal displacement of the proximal fragment by ≥10mm from the calcaneocuboid joint on lateral radiograph has 100% concordance with full thickness peroneus longus tendon tear demonstrated by MRI [Figs. 5-7] [3]. Fragment separation of 2 mm or less, or proximal displacement of 8 mm or less is associated with normal tendons, partial thickness tear, or only tendinosis [3]. As seen in this case prior to the peroneus longus tendon rupture, the normal os peroneum location ranges between 7 mm proximal and 8 mm distal to the calcaneocuboid joint [Fig. 3A][3]. The peroneus longus is a powerful evertor of the foot, thus surgical intervention is often necessary to repair a fully torn tendon. Since POPS may arise from a wide spectrum of conditions, the treatment is based upon the specific pathology [4]. Radiologists play an essential role in the diagnosis of POPS, and should be familiar with the appearance of both the normal os peroneum, and the various pathologic processes which may affect this accessory ossicle. References: 1. Ghagas-Neto FA, Caracas de Souza, BN, Nogueira-Barbosa MH. Painful Os Peroneum Syndrome: Underdiagnosed Condition in the Lateral Midfoot Pain. Case Reports in Radiology 8739362 (2016): 1-4. 2. Oh SJ, Kim YH, Kim SK, et al. Painful Os Peroneum Syndrome Presenting as Lateral Plantar Foot Pain. Annals of Rehabilitation Medicine 36.1 (2012): 163-66. 3. Brigido MK, Fessell DP, Jacobson JA, et al. Radiography and US of os peroneum fractures and associated peroneal tendon injuries: initial experience. Radiology. 2005;237 (1): 235-41. 4. Malhotra R, et al. Peroneal Tendon Pathology Treatment & Management. Medscape, 10 May 2016. Web. 13 Feb. 2017 Jesse Chen, MD Radiology Resident - Northwell/Staten Island University Hospital Dr. Chen is a radiology resident (class of 2020) at Staten Island University Hospital. He started residency as a general surgeon at Medstar Washington Hospital Center in DC, but transferred to radiology after 2 years. He graduated Magna Cum Laude from the University of Pennsylvania and then attended medical school at Georgetown University. Dr. Chen is currently the secretary/treasurer of the New York State Radiological Society (NYSRS) Residents and Fellows Section. Shirley Hanna, MD Section Chief, Division of Musculoskeletal Imaging - Northwell/Staten Island University Hospital Certified by the American Board of Radiology in 2011, Dr. Shirley Hanna joined the Northwell/Staten Island University Hospital faculty in 2012 after completing her fellowship in musculoskeletal and breast imaging at Yale-New Haven Hospital. Dr. Hanna graduated Magna Cum Laude from Seton Hall University and attended medical school at Rutgers-New Jersey Medical School where she was a member of ΑΩΑ. Dr. Hanna completed her transitional year of residency at St. Joseph’s Hospital Health Center in Syracuse, NY followed by her radiology residency at Yale-New Haven Hospital. She is now the the section chief of MSK imaging and Associate Chair of Radiology at Northwell/Staten Island University Hospital. Marlena Jbara, MD Attending, Division of Musculoskeletal Imaging - Northwell/Staten Island University Hospital Certified by the American Board of Radiology in 2001, Dr. Marlena Jbara has served as a member of the Bone and Joint division of Radiology at Staten Island University Hospital - Northwell Health since joining the team in 2008. Dr. Jbara, a summa cum laude graduate of the BA-MD Program at the State University of New York, was actively recruited by Dr. Javier Beltran for his nationally recognized MRI musculoskeletal and body fellowship program. Dr. Jbara is a leader in Podiatric Radiology, and has published articles and book chapters on the shoulder, knee and ankle. Her current interests include MRI evaluation of the Diabetic Foot and MR assessment of altered biomechanics, with respect to the foot and ankle. Cheryl Lin, MD Attending, Division of Musculoskeletal Imaging - Northwell/Staten Island University Hospital Certified by the American Board of Radiology in 2012, Dr. Cheryl Lin attended the 7-year BA-MD combined Sophie Davis School of Biomedical Education and graduated from SUNY Downstate College of Medicine, completed diagnostic radiology residency training in Staten Island University Hospital and musculoskeletal radiology fellowship in SUNY Stony Brook University Hospital. Dr. Lin specializes in sports injury imaging, orthopedic oncologic imaging and biopsy, podiatric medicine, musculoskeletal and general ultrasound, and cardiac coronary CTA imaging. She is also Section Chief in General Ultrasonography, and has a special interest in image-guided head/neck biopsies and musculoskeletal interventions such as therapeutic and diagnostic injections of joints and soft tissues. Ratheesraj (Raf) Ratinam, MBBS Monash University. Melbourne, Australia Dr. Raf Ratinam worked for several years as a surgical registrar at Monash Health in Melbourne, Australia. He has taken time away from his clinical work to undertake a PhD in the Department of Anatomy and Developmental Biology at Monash University. The PhD looks at applications of 3-Dimensional printing in hand surgery. Raf has worked for ten years as a medical illustrator and before commencing graduate medicine at Melbourne University he was working full time as an animator. His interests include oil painting, sculpting, calligraphy and archery. Follow Dr. Ratinam on Twitter @RafRatinam

Penetrating Wound to the Chest • Xray of the Week An 18 year-old presents with an injury to chest. What is the diagnosis? Figure 1. AP and lateral chest x-ray showing foreign bodies. What is the diagnosis? Figure 2. Annotated AP and lateral chest x-ray showing nail penetrating the right ventricle. Clip represents entry wound of the nail (red arrow). Mild enlargement of cardiac silhouette indicating pericardial effusion. Figure 3. Commercial pneumatic nail gun. Safety release (blue arrow) must be fully depressed (in the direction of red arrow) for nail to be ejected. Discussion Workplace injuries due to pneumatic nail guns are common despite manufacture safety features. Those with increased risk are workers with limited experience using nail guns or with inadequate training on the use of the devices (1,2,3). Compared to injuries to the extremities, penetrating wounds to the heart are uncommon. Though rare, the morbidity and mortality of penetrating nail gun wounds to the heart are high (2). Due to the penetrating injury, blood can accumulate in the pericardial sac. The hemopericardiun can lead to cardiac tamponade which is an immediate life-threatening situation in addition to the damage done to the heart by the nail. Surgical approaches to repair cardiac injuries for penetrating nail gun injuries include sternotomy or anterolateral thoracotomy. A pericardiocentesis may be necessary to stabilize the patient before surgery can be performed. Due to the safety features of nail guns and the difficulty of accidentally shooting one’s self in the chest, homicidal or suicidal intent should be considered (4), especially if the nail is unbent, which indicates the wound was not a result of a ricochet (5). References: 1. Beaver, A. C., & Cheatham, M. L. (1999). Life-threatening nail gun injuries. The American surgeon, 65(12), 1113. https://www.ncbi.nlm.nih.gov/pubmed/10597056 2. Chirumamilla, V., Prabhakaran, K., Patrizio, P., Savino, J. A., Marini, C. P., & Zoha, Z. (2016). Pericardiocentesis followed by thoracotomy and repair of penetrating cardiac injury caused by nail gun injury to the heart. International journal of surgery case reports, 23, 98-100. http://www.sciencedirect.com/science/article/pii/S2210261216300815 3. Lipscomb, H. J., Dement, J. M., Nolan, J., & Patterson, D. (2006). Nail gun injuries in apprentice carpenters: risk factors and control measures. American journal of industrial medicine, 49(7), 505-513.https://www.ncbi.nlm.nih.gov/pubmed/16758488 4. McCorkell, S. J., Harley, J. D., & Cummings, D. (1986). Nail-Gun Injuries: Accident, Homicide, or Suicide?. The American journal of forensic medicine and pathology, 7(3), 192-195. https://www.ncbi.nlm.nih.gov/pubmed/3788906 5. Nadesan, K, A Fatal Nail Gun Injury - An Unusual Ricochet? Medicine, Science and the Law. January 2000 http://journals.sagepub.com/doi/pdf/10.1177/002580240004000116 Christopher Williamson, MSMP 1st year medical student Medical College of Georgia at Augusta University Jayanth Keshavamurthy, MBBS Assistant Professor of Radiology Department of Radiology and Imaging Medical College of Georgia at Augusta University https://webapps.gru.edu/PROD/iflapi.viewfac?CGInetid=JKESHAVAMURTHY

Bilateral wrist pain • Xray of the Week 72 y.o. male presented with chronic bilateral wrist and hand pain. What is the diagnosis? Figure 1. Bilateral frontal hand and wrist radiographs. Figure 2. Right wrist radiograph. There is obliteration the radiocarpal joint between radius and scaphoid (red arrow). There is scapholunate advanced collapse (SLAC) with scapholunate dissociation and marked proximal migration of the capitate (green arrow). Deformity of the scaphoid and distal radius (red arrow) is due to remodeling related to the arthropathy. Note the radioulnar joint is relatively spared and there is no chondrocalcinosis in the joints or in the triangular fibrocartilage. Figure 3. Left wrist radiograph. There is obliteration the radiocarpal joint between radius and scaphoid (yellow arrow). There is scapholunate advanced collapse (SLAC) with scapholunate dissociation and marked proximal migration of the capitate (green arrow). Deformity of the scaphoid and distal radius (red arrow) is due to remodeling related to the arthropathy. Note the radioulnar joint is spared and there is no chondrocalcinosis in the joints or in the triangular fibrocartilage. Discussion Scapholunate Advanced Collapse (SLAC wrist) is due to advanced injury of the scapholunate and volar radioscapholunate ligaments which may lead to rotatory subluxation of the scaphoid and scapholunate dissociation. As in this severe case, the capitate may migrate proximally into the widened scapholunate space and articulate with the distal radius. ​CPPD crystal deposition disease and trauma are the major causes of SLAC wrist. Calcium Pyrophosphate Deposition Disease (CPPD Arthropathy) has the same appearance as degenerative joint disease (DJD) demonstrating sclerosis, joint space narrowing, and osteophyte formation. However, it tends to affect joints which are usually not seen with degenerative joint disease such as the radiocarpal joint, elbow, or restricted to the patellofemoral compartment of the knee. The distribution tends to be symmetric. Chondrocalcinosis is not always seen radiographically despite the presence of calcium crystals in the joint, and subchondral cysts may be prominent. Treatment options for advanced cases of SLAC wrist include partial fusion such as four-corner arthrodesis, or complete wrist arthrodesis, scaphoidectomy, proximal row carpectomy (PRC), denervation, and radial styloidectomy. References: 1. Resnick D, Niwayama G, Goergen TG, et-al. Clinical, radiographic and pathologic abnormalities in calcium pyrophosphate dihydrate deposition disease (CPPD): pseudogout. Radiology. 1977;122 (1): 1-15 2. Helms CA, Vogler JB, Simms DA, et al. CPPD crystal deposition disease or pseudogout. RadioGraphics 1982; 2 (1); 40-52 3. Brower AC, USNR DJFMDCDRMC. Arthritis in Black and White. Saunders. ISBN:1416055959. Read it at Google Books - Buy it on Amazon 4. Saffar P. Chondrocalcinosis of the wrist. Journal of hand surgery (Edinburgh, Scotland). 29 (5): 486-93. 5. Resnick D, Utsinger PD. The wrist arthropathy of “pseudogout” occurring with and without chondrocalcinosis. Radiology 1974; 113:633-641. 6. Chen C, Chandnani VP, Kang HS, Resnick D, et-al. Scapholunate advanced collapse: a common wrist abnormality in calcium pyrophosphate dihydrate crystal deposition disease. Radiology. 1990;177 (2): 459-61. 7. Doherty W, Lovallo JL. Scapholunate advanced collapse pattern of arthritis in calcium pyrophosphate deposition disease of the wrist. J Hand Surgery. 1993;18(6):1095-1098 8. Merrell GA, McDermott EM, Weiss AP. Four-corner arthrodesis using a circular plate and distal radius bone grafting: a consecutive case series. J Hand Surg Am. 2008;33 (5): 635-42. 9. Steinbach LS, Resnick D. Calcium pyrophosphate dihydrate crystal deposition disease revisited. State of the Art. Radiology. 1996;200:1-9. Kevin M. Rice, MD is president of Global Radiology CME and serves as the Chief of Staff and Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. Dr. Rice co-founded Global Radiology CME with Natalie Rice 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 Steven Kussman, MD is a Musculoskeletal Radiologist at Renaissance Imaging Medical Associates in Los Angeles, California. After completing an undergraduate degree in Biology and graduating Magna Cum Laude at Brown University, he went on to Medical School at Boston University. Dr. Kussman was selected to the become a member of the prestigious Alpha Omega Alpha Honor Medical Society in 2008 and graduated Magna Cum Laude in 2009. He was Chief Radiology Resident at Boston University and completed his radiology residency at Boston University in 2014. Following residency, Dr. Kussman then did a one year fellowship in Musculoskeletal Imaging at UC San Diego in 2014-2015. Dr. Kussman's publications can be found here. He lives in Los Angeles with his wife and son and in his spare time loves to play and watch sports.

A 47-year-old status post rock climbing injury of his finger. Now has deformity of the palmar aspect of the finger with flexion. What is the diagnosis? Figure 1. What is abnormal in this digital image? A. Sagittal image of finger in flexion. B. Axial image of finger. C. Sagittal image of finger in extension. Figure 2. ABNORMAL FINGER A. Sagittal image of finger in flexion. The flexor tendon is bow stringed with respect to the proximal phalanx. (yellow arrow) B. Axial image of finger. There is a tear of the A1 pulley with retraction of the pulley fibers dorsally. The flexor digitorum superficialis tendon is split down the middle and mildly subluxed peripherally. Notice the marked soft tissue edema and tenosynovitis surrounding the flexor tendon. (green arrow) C. Sagittal image of finger in extension. The flexor tendon is less bow stringed with respect to the proximal phalanx when extended. (red arrow) Figure 3. NORMAL FINGER A. Sagittal image of the normal adjacent finger in flexion. Notice that the flexor tendons hug the palmar surface of the proximal phalanx. (yellow arrow) B. Axial image of the normal adjacent finger in flexion. Notice that the flexor tendons hug the palmar surface of the proximal phalanx. (green arrow) C. Sagittal image of the normal adjacent finger in extension. The flexor tendons hug the palmar surface of the proximal phalanx. (red arrow) Figure 4. Diagram of the normal digital flexor pulley system. Diagram from: https://theclimbingdoctor.com/pulley-injuries-explained-part-1/ Figure 5. Diagram of the normal digital flexor pulley system. Figure 6. Diagram of the digital flexor pulley system with a tear of the A2 and A3 pulleys. Figure 7. Intraoperative images of patient in Figure 1-3. A. First picture shows torn pulley. B. Palmaris graft harvested. C. Graft dorsal to bone and volar to extensor. D. Final picture tied down. Figure 8. Rock climbing with the crimp grip. Note the extension of the MCP joints, flexion of the PIP joints, and extension of the DIP joints. When using the crimp grip rather than an open hand grip, the force on the A4 pulley increases 3.9 times and the force on the A2 pulley increases 31.5 times. Discussion: The flexor tendons of the finger travel through a fibro-osseous tunnel along the palmar aspect of the fingers. The fibrous portion of the canal includes five annular pulleys which are perpendicular to the long axis of the tunnel and are separate areas of thickening of the tendon sheaths. There are also three cruciform pulleys which crisscross fibers of the annular pulleys. The annular pulleys are named A1 through A5 and the cruciate pulleys are named C1 through C3. The A1 pulley originates in the palmar plate of the metacarpal phalangeal joint and extends to the base of the proximal phalanx and is intimately related to the metacarpal phalangeal joint. The A2 pulley originates along the volar proximal aspect of the proximal phalanx and spans the distance to the distal third of the proximal phalanx. The A3 pulley spans over the proximal interphalangeal joint, A4 is located palmar to the mid aspect of the middle phalanx, while the A5 pulley spans the DIP joint. The main role of the annular pulleys is to stabilize the tendon sheaths to the phalanges. The function of the pulley system is to prevent bowstringing of the tendons on finger flexion. One analogy is the eyelets of a fishing rod. Flexor injuries are commonly encountered during forced extension on a flexed finger such as occurs when using the “crimp grip” during rock climbing. In fact, the crimp grip transfers 31.5 times more force on the A2 pulley than an open-hand grip. (Fig 8.) Flexor pulley injuries have also been reported in bowling, baseball and other sports. MRI is the main imaging method, however ultrasound is playing an increasingly important role in evaluation due to the possibility of dynamic assessment. All A2 and most A4 pulley ruptures require surgical repair in order to regain function. A1, A3 and A5 pulleys may be initially managed conservatively. References and further reading: 1. Singh AP. Flexor Tendon Pulley System of Hand. http://boneandspine.com/flexor-tendon-pulley-system-of-hand/ 2. Whitney Lowe W.Flexor Pulleys of the Fingers. Massage Today May, 2010, Vol. 10, Issue 05 http://www.massagetoday.com/mpacms/mt/article.php?id=14209 3. Awh MH. Pulley Lesions of the Fingers. http://radsource.us/pulley-lesion-of-the-fingers/ 4. Rock Climbers and Pulleys. http://musculoskeletalmri.blogspot.com/2011/05/rock-climbers-and-pulleys.html 5. Rubin DA, Kneeland JB, Kitay GS, Naranja RJ. Flexor Tendon Tears in the Hand: Use of MR Imaging to Diagnose Degree of Injury in a Cadaver Model. AJR 1996;166:615-620 6. Drape J, et al. Closed ruptures of the flexor digitorum tendons: MRI evaluation. Skeletal Radiology 1998;27:617-624. 7. Clavero JA, Alomar X, Monill JM, et. al. MR Imaging of Ligament and Tendon Injuries of the Fingers. RadioGraphics 2002 22:2, 237-256 8. Lin GT, Amadio PC, An KN, Cooney WP. Functional anatomy of the human digital flexor pulley system. J Hand Surg [Am ]1989; 14:949–956. 9. Crowley TP. The Flexor Tendon Pulley System and Rock Climbing. J Hand Microsurg (2012) 4: 25. 10. Zafonte, Brian et al. Flexor Pulley System: Anatomy, Injury, and Management. Journal of Hand Surgery ,2014, Volume 39 , Issue 12 , 2525 - 2532 11. Bianchia S, Martinoli C, de Gautarda R, et. al. Ultrasound of the digital flexor system: Normal and pathological findings. J Ultrasound. 2007 Jun; 10(2): 85–92. 11. Vigouroux L, Quaine F, Labarre-Vila A, Moutet F-O. Estimation of finger muscle tendon tensions and pulley forces during specific sport-climbing grip techniques. J Biomech. 2006;39:2583-2592. doi:10.1016/j.jbiomech.2005.08.027 12. Pulley Injuries in Fingers. http://bouldersuk.com/2013/11/pully-injuries-fingers/ Phillip Tirman, MD is the Medical Director of Musculoskeletal Imaging at the Renaissance Imaging Center in Westlake Village, California. A nationally recognized expert in the applications of MRI for evaluating MSK and spine disorders, Dr. Tirman is the co-author of three textbooks, including MRI of the Shoulder and Diagnostic Imaging: Orthopedics. He is also the author or co-author on over sixty original scientific articles published in the radiology and orthopedic literature. All posts by Phillip Tirman, MD Kevin M. Rice, MD is president of Global Radiology CME and serves as the Chief of staff and Chair of the Radiology Department of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. Dr. Rice co-founded Global Radiology CME with Natalie Rice 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

Fixed Abduction of Left Shoulder After a Fall • Xray of the Week 80 y.o. female with left shoulder pain and deformity after a fall. What is the diagnosis? Figure 1. Frontal left shoulder radiograph. Figure 2. Annotated frontal left shoulder radiograph. The humeral head is dislocated inferiorly (red arrow) and the shaft of the humerus is parallel to the scapular spine (yellow arrows). Figure 3. CT scan of left shoulder. A. Coronal image. There is inferior dislocation of the humeral head (red arrow) relative to the glenoid (yellow arrow). B. Sagittal image. There is inferior dislocation of the humeral head (red arrow) relative to the glenoid. Also note the well corticated old Bankart fracture of the anterior glenoid (yellow arrow) indicating previous anterior glenohumeral dislocation. Discussion Seen in less than 1% of cases, inferior shoulder dislocation is the rarest type of shoulder dislocation. The mechanism of injury is either sudden forceful arm hyperabduction or direct force on fully abducted arm. Luxatio erecta, refers to the abduction deformity that is a result of the of the humeral head situated inferior to the glenoid resulting in the patient presenting with the arm held upright. This injury has the has highest incidence of neurovascular injury of all types of shoulder dislocations with neurologic injury to the brachial plexus in up to 60% of cases and vascular injury to the axillary artery in up to 39% of cases. Plain radiographs in cases of inferior shoulder dislocation typically demonstrate the humeral head located inferior to the glenoid. The finding of fixed abduction of the shoulder with the shaft of the humerus parallel to the scapular spine (Figs. 1 and 2) is pathognomonic of luxatio erecta. Due to the high incidence of complications, MRI should be performed after the dislocation has been reduced. Common MRI findings include rotator cuff tears, glenoid labrum tears, and injury to both the anterior and posterior bands of the inferior glenohumeral ligament. Treatment consists of closed reduction and immobilization; however, surgery may be indicated in active patients who have capsulolabral damage or rotator cuff tear. • Rarely inferior hip dislocation can present with luxatio erecta as seen on this Global Radiology CME Case: Inferior Hip Dislocation with Luxatio Erecta References: 1. Yao F, Zhang L, Jing J. Luxatio erecta humeri with humeral greater tuberosity fracture and axillary nerve injury. Am J Emerg Med. 2018 Oct;36(10):1926.e3-1926.e5. https://www.ncbi.nlm.nih.gov/pubmed/30238913 2. Ngam PI, Hallinan JT, Sia DSY. Sequelae of bilateral luxatio erecta in the acute post-reduction period demonstrated by MRI: a case report and literature review. Skeletal Radiol. 2019 Mar;48(3):467-473. https://www.ncbi.nlm.nih.gov/pubmed/30151632 3. Carbone S, Papalia M, Arceri V, Placidi S, Carbone A, Mezzoprete R. Humeral head inferior subluxation in proximal humerus fractures. Int Orthop. 2018 Apr;42(4):901-907. https://www.ncbi.nlm.nih.gov/pubmed/29116358 4. Brady WJ, Knuth CJ, Pirrallo RG (1995) Bilateral inferior glenohumeral dislocation: luxatio erecta, an unusual presentation of a rare disorder. J Emerg Med 13:37–42. https://www.jem-journal.com/article/0736-4679(94)00110-3/pdf 5. Baba AN, Bhat JA, Paljor SD, et. al. Luxatio erecta: inferior glenohumeral dislocation—a case report. International Journal of Shoulder Surgery. 2007(1)3:100–102. https://doi.org/10.4103%2F0973-6042.34026 6. Yamamoto T, Yoshiya S, Kurosaka M, et. al. Luxatio erecta (inferior dislocation of the shoulder): a report of 5 cases and a review of the literature. Am J Orthop (Belle Mead NJ). 2003 Dec;32(12):601-603. https://www.ncbi.nlm.nih.gov/pubmed/14713067 7. Davids JR, Talbott RD (1990) Luxatio erecta humeri. A case report. Clin Orthop 252:144-149. https://www.ncbi.nlm.nih.gov/pubmed/2302879 8. Mallon WJ, Bassett FH, Goldner RD. Luxatio erecta: the inferior glenohumeral dislocation. J Orthop Trauma. 1990;4 (1): 19-24. https://doi.org/10.1097%2F00005131-199003000-00003 9. Camarda L, Martorana U, D'Arienzo M. A case of bilateral luxatio erecta. Journal of Orthopaedics and Traumatology, vol. 10, no. 2, pp. 97–99, 2009. https://doi.org/10.1007%2Fs10195-008-0039-x 10. Matsumoto K, Ohara A, Yamanaka K, Takigami I, Naganawa T. Luxatio erecta (inferior dislocation of the shoulder): a report of two cases and a review of the literature. Injury Extra. 2005;36:450–3. https://www.sciencedirect.com/science/article/pii/S1572346105000644?via%3Dihub 11. Mohseni MM. Images in emergency medicine: luxatio erecta (inferior shoulder dislocation). Ann Emerg Med. 2008;52:203–31. https://www.annemergmed.com/article/S0196-0644(07)01798-2/fulltext 12. Ngam PI, Hallinan JT, Sia DSY. Sequelae of bilateral luxatio erecta in the acute post-reduction period demonstrated by MRI: a case report and literature review. Skeletal Radiol. 2019 Mar;48(3):467-473. doi: 10.1007/s00256-018-3047-9 13. Hassanzadeh E, Chang CY, Huang AJ, et. al. CT and MRI manifestations of luxatio erecta humeri and a review of the literature. Clin Imaging. 2015 Sep-Oct;39(5):876-9. doi: 10.1016/j.clinimag.2015.04.009 14. Krug DK, Vinson EN, Helms CA. MRI findings associated with luxatio erecta humeri. Skeletal radiology. 39 (1): 27-33. doi:10.1007/s00256-009-0786-7 Kevin M. Rice, MD is president of Global Radiology CME and serves as the Chief of Staff of Valley Presbyterian Hospital in Los Angeles, California and is a radiologist with Renaissance Imaging Medical Associates. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. Dr. Rice co-founded Global Radiology CME with Natalie Rice 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

29F with trauma and headache • Xray of the Week Figure 1. What is the important finding on this CT scan. Figure 2. A. Coronal CT brain with standard window width of 70. It is very difficult to visualize the left superior parietal acute subdural hematoma. B. Coronal CT brain with wider window width of 150. Note the small superior parietal acute subdural hematoma (red arrow). Figure 3. Coronal and axial CT brain with standard window width of 70. It is very difficult to visualize the left superior parietal acute subdural hematoma. SDH is not well seen on the axial image, even on a wide window, due to the hematoma being in the same plane. Figure 4. Sagittal CT of a different patient with atrophy which demonstrates several bridging cortical veins (white arrows) as they cross the subdural space and drain into the superior sagittal sinus. Subdural hemorrhages are due to tearing of these veins when there is a rapid acceleration or deceleration of the head. Discussion: Acute subdural hematoma (SDH) occurs when blood accumulates in the subdural space, between the arachnoid and dura layers of the brain (1,4). They can result from traumatic accidents that cause tears in the bridging veins that cross the subdural space. Acute SDH's are common in the elderly because brain atrophy during aging causes the bridging veins to stretch, making them more susceptible to tears (2) (Fig. 4). Other etiologies of acute SDH include coagulopathy or medical coagulation, non-traumatic hemorrhage, surgery, and intracranial hypotension (3). Acute SDH's are typically unilateral and can be visualized as crescent-shaped and hyperdense regions on CT (1,4). The acute SDH in this case is seen only with wide windowing. Small SDH's such as the one in this case may be difficult to detect with standard brain windows compared to the subdural window so it is important to window the CT scan appropriately for smaller hematomas (1). In addition, this SDH was not well seen on the axial images due to the hematoma being in the same plane (Fig.3). SDH's can usually be distinguished from epidural hematomas since epidural hematomas have a biconcave-lens appearance on CT and show pooling of blood between the skull and the dura mater and they cannot expand past the sutures of the skull (1,4). Purulent accumulation of cerebrospinal fluid in the subarachnoid space can also have a similar appearance to SDH's, especially when there is decreased brain mass (4). Patients with subarachnoid hemorrhage due to ruptured aneurysms may also present with hyperdense subdural effusions which appear similar to acute SDH's but they may resolve on follow-up examination (5). Acute SDH can be distinguished from subacute and chronic SDH on CT. Subacute SDH will appear isodense to grey matter on CT (6). Chronic SDH will appear isodense to CSF on CT often with a biconvex shape rather than a crescentic shape, and it can also appear as a calcified mass (7). Treatment for acute SDH is usually surgical particularly when there is neurologic deficit. Moreover, surgery is indicated if the clot thickness is more than 1 cm or midline shift is more than 0.5 cm, even without significant neurologic deficit (8). Conservative management may be used in asymptomatic patients with small or chronic SDH (8). In this particular case, the SDH resolved without surgery. ​​​​ References: 1. Heit JJ, Iv M, Wintermark M. Imaging of Intracranial Hemorrhage. J Stroke. 2017;19(1):11-27. doi:10.5853/jos.2016.00563 2. Miller JD, Nader R. Acute subdural hematoma from bridging vein rupture: a potential mechanism for growth. J Neurosurg. 2014;120(6):1378-1384. doi:10.3171/2013.10.JNS13272 3. Vega RA, Valadka AB. Natural History of Acute Subdural Hematoma. Neurosurg Clin N Am. 2017;28(2):247-255. doi:10.1016/j.nec.2016.11.007 4. Pierre L, Kondamudi NP. Subdural Hematoma. [Updated 2019 Dec 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532970/ 5. Zamora CA, Lin DD. Enhancing subdural effusions mimicking acute subdural hematomas following angiography and endovascular procedures: report of 2 cases. J Neurosurg. 2015;123(5):1184-1187. doi:10.3171/2014.10.JNS142172 6. Yadav YR, Parihar V, Namdev H, Bajaj J. Chronic subdural hematoma. Asian J Neurosurg. 2016;11(4):330-342. doi:10.4103/1793-5482.145102 7. Kpelao E, Beketi KA, Moumouni AK, et al. Clinical profile of subdural hematomas: dangerousness of subdural subacute hematoma. Neurosurg Rev. 2016;39(2):237-240. doi:10.1007/s10143-015-0669-4 8. Gerard C, Busl KM. Treatment of Acute Subdural Hematoma. Curr Treat Options Neurol. 2014 Jan;16(1):275. doi: 10.1007/s11940-013-0275-0 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