Nivolumab-induced small bowel obstruction and perforation: a rare but life-threatening side effect of immunotherapy.

We present a case of a 58-year-old female with anti-PD-1 immunotherapy-related small bowel perforation. The patient was on long-term therapy with nivolumab for metastatic non-small cell lung cancer. She presented to the emergency department with acute abdominal pain, in which the CT revealed a short segment of dilated distal ileum proximal to a very short segment of bowel with mural thickening and a perforation near the transition point. The patient underwent subsequent laparotomy, which confirmed the CT findings and revealed a short-segment of friable and dilated loop of distal ileum proximal to a stricture and a small perforation at the transition point. Pathological analysis revealed mural thickening at the site of stricture without evidence of malignancy with focal necrosis and perforation at the transition point. Bowel perforation in the setting of anti-PD-1 immunotherapy is rare, but life-threatening complication, and should be considered in oncology patients on immunotherapy presenting with severe abdominal pain.

Temporal Trends in Imaging Utilization for Suspected Substance Use Disorder in an Academic Emergency Radiology Department.

PURPOSE: To assess temporal trends and utilization patterns of diagnostic imaging performed for substance use disorder (SUD)-related indications in an academic radiology emergency department (ED). METHODS: Retrospective analyses of ED imaging examinations acquired from 2005 to 2015 were performed. Imaging examinations performed for suspected SUD-related indications, based on the order history, were compared with those without a SUD-related indication. Unadjusted analyses comparing demographic and imaging characteristics between SUD-related versus non-SUD-related indications used Wilcoxon and Pearson's χ2 tests. Multivariable logistic regression models, within each imaging modality subgroup and combined, were employed to examine the odds of imaging examinations having an SUD-related indication as a function of demographic and imaging characteristics. RESULTS: Among 938,245 examinations, 0.17% had an SUD-related indication. Patients with SUD-related indications were younger (mean 37.2 ± 11.1 versus 53.5 ± 22.4, P < .001) and more commonly male (65% versus 52%, P < .001). The proportions of MR (17%), spine (17%), and extremities (33%) studies performed for SUD-related indications were larger among SUD than non-SUD indications (6%, 8%, 26%, respectively, all P < .001). Regression analysis demonstrated the odds of acquiring an ED imaging examination with an SUD-related indication significantly increased over time (P < .001, adjusted odds ratio [aOR] = 1.06), which was most pronounced among MR (P < .001, aOR = 1.23). For all regression models, younger age, male gender, and body part being imaged were identified as independent predictors of an SUD-related indication for ED imaging. CONCLUSION: Imaging performed for an SUD-related indication represented a small but increasing subset of overall ED imaging. Utilization of MR for SUD-related indications significantly outpaced growth of MR without SUD-related indications.

Accuracy and timeliness of an abbreviated emergency department MRCP protocol for choledocholithiasis.

PURPOSE: To determine the diagnostic accuracy and time savings of an abbreviated magnetic resonance cholangiopancreatography (A-MRCP) protocol for detecting choledocholithiasis in patients visiting the emergency department (ED) for suspected biliary obstruction. METHODS AND MATERIALS: This retrospective study evaluated adult patients (ages 18+ years) visiting an academic Level 1 trauma center between January 1, 2016, and December 31, 2017, who were imaged with MRCP for suspected biliary obstruction. Patients were scanned with either a four-sequence A-MRCP protocol or a conventional eight-sequence MRCP (C-MRCP) protocol. Image acquisition and MRI room time were compared. The radiology report was used to determine whether a study was limited by motion or prematurely aborted, as well as for the presence of pertinent biliary findings. Diagnostic accuracy of A-MRCP studies were compared with any available endoscopic retrograde cholangiopancreatography (ERCP) report within 30 days. RESULTS: One hundred sixteen patients met inclusion criteria; 85 were scanned with the A-MRCP protocol (45.9% male, mean 57.4 years) and 31 with the C-MRCP protocol (38.7% male, mean 58.3 years). Mean image acquisition time and MRI room time for the A-MRCP protocol were significantly lower compared to those for the C-MRCP protocol (16 and 34 min vs. 42 and 61 min, both p < 0.0001). Choledocholithiasis was seen in 23.5% of A-MRCP cases and 19.4% of C-MRCP cases. Non-biliary findings were common in both cohorts, comprising 56.5% of A-MRCP cases and 41.9% of C-MRCP cases. 44.7% of A-MRCP patients received subsequent (diagnostic or therapeutic) ERCP (mean follow-up time 3 days), in which A-MRCP accurately identified choledocholithiasis in 86.8% of cases, with sensitivity of 85%, specificity of 88.9%, positive predictive value (PPV) of 89.5%, and negative predictive value (NPV) of 84.2%. In comparison, 38.7% of C-MRCP patients underwent ERCP (mean follow-up of 2.3 days) with an accuracy of 91.7%, sensitivity of 80%, specificity of 100%, PPV of 100%, and NPV of 87.5%. Only 4.7% of A-MRCP exams demonstrated motion artifact vs. 12.9% of C-MRCP exams. One study was prematurely aborted due to patient discomfort in the A-MRCP cohort while no studies were terminated in the C-MRCP cohort. CONCLUSION: An abbreviated MRCP protocol to evaluate for choledocholithiasis provides significant time savings and reduced motion artifact over the conventional MRCP protocol while providing similar diagnostic accuracy.

The added value of cross-sectional imaging in the detection of additional radiographically occult fractures in the setting of a Chopart fracture.

PURPOSE: Radiography has a low sensitivity for the detection of fractures related to the talonavicular and calcaneocuboid articulations, also known as Chopart fractures. The purpose of this study is to determine the sensitivity of radiographs for detecting additional foot and ankle fractures related to Chopart fracture using CT or MRI as the reference standard. METHOD: We performed an IRB-approved, retrospective review of radiology reports between 2010 and 2014. Inclusion criteria were (1) diagnosis of a Chopart fracture and (2) at least one radiograph and subsequent cross-sectional imaging (CT or MR). CT or MRI was considered the diagnostic reference standard. Results were stratified by the energy of trauma and by type of radiograph performed (weight-bearing (WB) versus non-WB). RESULTS: One hundred eight patients met the inclusion criteria. The calcaneocuboid articulation was the most commonly involved type of Chopart fracture, seen in 75% of cases (81/108). Chopart fractures were detected on the initial radiographs in 67.6% of cases (73/108). Additional fractures of the ankle and midfoot were diagnosed in 34.2% of cases (37/108), with 56.7% (21/37) of these cases having at least one additional fracture seen on CT or MRI that was not seen on the initial radiographs, with fractures of the midfoot most often missed. In 56.7% (17/30) patients whose radiographs detected Chopart fractures, at least one additional fracture was missed; 30% of them demonstrated intra-articular extension and 56.7% were considered displaced. High-energy trauma was related to higher incidence of additional fractures. There was no significant difference in the sensitivity of radiographs to detect additional fractures between high versus low-energy trauma (p = 0.3) and WB versus non-WB radiographs (p = 0.5). Most patients were treated nonoperatively (56.5%, 61/108), with surgical intervention more frequent in patients with a high energy of trauma (51.7% versus 33.3%, p = 0.05). CONCLUSION: In the setting of a Chopart fracture, CT or MRI can add significant value in the detection of additional ankle or midfoot fractures, irrespective of the energy of trauma. Since additional fractures can have important management implications, CT or MRI should be considered as part of the standard workup for all midfoot fractures.

Necrotizing fasciitis of the lower extremity: imaging pearls and pitfalls.

OBJECTIVE: The purpose of this article is to review the imaging findings of necrotizing fasciitis as seen on radiograph, ultrasound, CT, and MRI, and to recognize the early findings in this potentially fatal disease. CONCLUSION: Although classically a clinical diagnosis, imaging is a powerful adjunct to facilitate early diagnosis in equivocal cases. Compared to plain radiography, ultrasound, CT and MR provide higher sensitivity and specificity for the diagnosis of necrotizing fasciitis. Cross-sectional imaging findings include asymmetric thickening of fascia, soft tissue air, blurring of fascial planes, inflammatory fat stranding, reactive lymphadenopathy, and nonenhancement of muscular fascia.

Extrahepatic metastases of hepatocellular carcinoma: A spectrum of imaging findings.

Hepatocellular carcinoma (HCC) is the most common primary tumour of the liver, responsible for significant morbidity and mortality worldwide. In the Western world, it primarily affects patients with cirrhosis, secondary to hepatitis C virus and alcoholism. In the rest of the world, HCC is closely associated with hepatitis B virus infections. Radiologists play a key role in accurately staging HCC, which has important implications for treatment planning. This pictorial review aims to describe the routes of HCC spread and the most frequent sites of metastases, to recognize extrahepatic HCC findings on computed tomography and magnetic resonance imaging, and to understand the implications of HCC staging on treatment planning.

Imaging of blunt vascular neck injuries: a review of screening and imaging modalities.

OBJECTIVE: We will review the epidemiology of blunt cerebrovascular injuries (BCVIs) and the rationale for screening. Current imaging modalities used to screen for BCVIs will be discussed with an emphasis on CT angiography. CONCLUSION: Screening for BCVIs can decrease rates of postinjury complications, such as stroke. The use of standardized screening criteria and the appropriate imaging modalities can allow early detection of BCVIs and effective intervention.

Imaging of blunt vascular neck injuries: a clinical perspective.

OBJECTIVE: We will review the common injuries and anatomic distributions of blunt cerebrovascular injuries (BCVIs) of the neck, explain the grading criteria, and discuss the corresponding management. Artifacts associated with BCVI on CT will also be examined. CONCLUSION: Identifying common injury patterns and anatomic distributions associated with BCVI can help decide the grade and management earlier and reduce the risk for potential complications. Recognizing the common artifacts associated with BCVI helps the reader successfully recognize a true BCVI.

Rapid imaging protocol in trauma: a whole-body dual-source CT scan.

The purpose of this study is to determine whether a single acquisition whole-body trauma multi-detector CT scan is able to reduce resuscitation time, scan time, and effective radiation dose without compromising diagnostic quality in the setting of polytrauma. Retrospective analysis of 33 trauma patients undergoing single acquisition whole-body CT with injury severity scores of ≥ 16 was compared to 34 patients imaged with a segmented whole-body CT protocol. Time spent in the emergency department, effective radiation dose, image quality, and mortality rates were compared. The single acquisition group spent 53.7 % less time in the emergency department prior to imaging (p=0.0044) and decreased scanning time by 25 %. The protocol yielded a 24.5 % reduction in mean effective radiation dose (24.66 mSv vs. 32.67 mSv, p<0.0001). The image noise was similar in both groups. Standardized mortality ratios were comparable. The single acquisition protocol significantly reduces time spent in the emergency department by allowing faster imaging at a lower radiation dose while maintaining image quality. Other contributors to reduction in radiation dose include use of dual-source CT technology, removal of delayed CT intravenous pyelogram, and arm positioning.

Clinical utility of ultra high pitch dual source thoracic CT imaging of acute pulmonary embolism in the emergency department: are we one step closer towards a non-gated triple rule out?

OBJECTIVES/PURPOSE: Aim of this study was to retrospectively compare the image quality and the radiation dose of an ultra high pitch CT scan for the evaluation of pulmonary embolism and visualization of cardiac structures in comparison to our institution's standard pulmonary embolism protocol. METHOD AND MATERIALS: The study cohort consisted of 115 consecutive patients, 57 underwent CT pulmonary angiography on a dual source 128 slice scanner (Siemens Somatom Definition FLASH) via an ultra high pitch mode (Pitch 2.8) while 58 were scanned on a dual source 64 slice scanner (Siemens Somatom Definition Dual Source) with standard pitch (Pitch 0.9). Qualitative image assessment was determined by two blinded radiologists with 3 and 15 years' experience in chest and cardiac CT. Quantitative image assessment was determined by the signal to noise ratio (SNR) and contrast to noise ratio (CNR). Effective radiation dose was calculated via the product of the dose length product. RESULTS: For the ultra high pitch protocol, 14% (8/57) were positive for pulmonary embolus compared to 13.7% (8/58) for the standard pitch group. 98.2% of the ultra high pitch scans were diagnostic for pulmonary embolus vs. 94.8% of the standard protocol. Visualization of cardiac structures was significantly improved with the ultra high pitch protocol (p<0.0001). Significantly more lung parenchymal motion was observed on the standard protocol (p<0.0001). The mean pulmonary vessel attenuation, SNR, and CNR were not significantly different. The mean effective dose was lower for the ultra high pitch studies (4.09mSv±0.78 vs. 7.72mSv±2.60, p<0.0001). CONCLUSION: Ultra high pitch CT imaging for pulmonary embolus is a technique which has potential to assess motion free evaluation of most cardiac structures and proximal coronary arteries at lower radiation doses.

Reducing blood-borne exposure in interventional radiology: what the IR should know.

Interventional radiologists are at risk of exposure to blood-borne pathogens in their day-to-day practice. Percutaneous exposure from unsafe sharps handling, mucocutaneous exposure from body fluid splashes, and glove perforation from excessive wear can expose the radiologist to potentially infectious material. The increasing prevalence of blood-borne pathogens, including hepatitis B and C, and human immunodeficiency virus, puts nurses, residents, fellows, and interventional radiologists at risk for occupational exposure. This review outlines suggestions to establish a culture of safety in the interventional suite.

Cardiovascular disease in Chinese Canadians: a case-mix study from an urban tertiary care cardiology clinic.

BACKGROUND: Cardiovascular diseases (CVD) are the leading cause of death in Canada. Non-European ethnic groups such as the Chinese constitute an increasingly significant sector of the Canadian population. OBJECTIVE: To compare the frequency and risk factors of CVD in Chinese and white Canadians in a cardiology referral clinic that saw a high number of ethnic Chinese patients and provided equal access to advanced diagnostic facilities. PATIENTS AND METHODS: Clinic charts of patients referred between 1994 and 1999 were reviewed. Patients of Chinese descent were identified by their names. Primary cardiovascular and secondary cardiovascular diagnoses, as well as risk factors for coronary artery disease (CAD), were established. The frequency of disease and risk factors were age-standardized. RESULTS: The sample of patients with CVD consisted of 404 Chinese and 1129 white subjects. Chinese patients were older (median age 65 versus 62 years, P=0.006). CAD, heart failure and peripheral vascular disease were less frequent in Chinese than in white patients. On the other hand, valvular heart disease was more frequent in Chinese patients. Diabetes, smoking and family history of heart disease were less frequent in Chinese subjects, whereas the frequencies of hypertension and hypercholerolemia were similar to those of white patients. In patients who had undergone coronary angiography, the frequency of multivessel CAD was less in Chinese patients (40% versus 56%, P=0.0016). Angina pectoris was a more common manifestation of CAD in Chinese patients, whereas myocardial infarction was more common in people who were white. In patients with heart failure, the median left ventricular ejection fraction was higher in Chinese than in white patients (34% versus 28%, P=0.031). CONCLUSIONS: In patients referred to a cardiology clinic, the diagnosis of CAD and the majority of other CVDs was less frequent in Chinese Canadians than in white Canadians. However, selected modifiable risk factors for CAD, such as hypertension and hypercholesterolemia, were equally frequent. Further research at the population level is warranted to define the characteristics of CVD in Chinese Canadians, and may be useful to the future design of disease management and prevention programs tailored to the needs of this growing ethnic population.