Core curriculum illustration: pediatric viral parotitis The published version of this article unfortunately contained a mistake in the Abstract section.

Misleading CT perfusion in subacute ischemic stroke Abstract The RAPID© software is the most commonly used computed tomography perfusion (CTP) software in stroke centers. It is estimated that about 1300 hospitals in the world are using this software for decision-making in ischemic stroke. The software provides the estimated volume of infarction and ischemic penumbra, so it is the backbone of treatment planning in these patients. In this manuscript, we present two cases of subacute infarction with misleading CTP using RAPID© software. We believe that given the popularity of this software and increasing application of CTP in subacute infarction, this pitfall is likely underdiagnosed in many patients. In a subacute phase of infarction, we recommend diffusion-weighted imaging magnetic resonance imaging (DWI-MRI) for estimation of infarction to avoid this pitfall and possible mismanagement.

Core curriculum case illustration: cardiac tamponade complicating proximal aortic dissection Abstract This is the 39th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.erad.org/page/CCIP_TOC.

CT angiograms of the neck in strangulation victims: incidence of positive findings at a level one trauma center over a 7-year period Abstract Purpose To determine the incidence of acute findings diagnosed with computed tomography angiography (CTA) of the neck among emergency department patients presenting with strangulation injury. Method and materials This institutional review board-approved, HIPAA-compliant retrospective review was performed at our academic urban level 1 trauma center. The PACS database was queried for all consecutive patients who had CTAs of the neck performed for the exam indication of strangulation between January 1, 2009, and April 30, 2016, resulting in 142 included patients. Analysis of the individual cases was then performed, recording any positive results, with clinical findings classified using, when possible, standardized terminology found in the literature. Frequency of acute injury in the CTA neck examinations was determined with the calculation of 95% confidence interval (CI) and positive clinical findings were evaluated by calculation of prevalence. Additionally, two board certified radiologists with training in neuroradiology assessed the cases for vascular injury. Results There were 142 patients who met inclusion criteria (average age, 32.6 years) and 116 (81.7%) patients were female. CTA of the neck revealed 21 patients to have acute injuries (15.5%, 95% CI 9.5, 21.4) including 6 initially reported vascular injuries (4.2%, 95% CI 0.9, 7.5). Although neck pain (73, 51.4%), loss of consciousness (67, 47.2%), and headache (31, 21.8%) were frequently reported in the ROS, their predictive value of vascular injury was weak (4.1%, 4.5%, and 3.2%, respectively). On physical exam, redness/bruising of the neck (73, 51.4%) and neck tenderness (47, 33.1%) were both the most common and had the highest prevalence (19.2% and 12.8%, respectively), however, when selecting for vascular injuries alone were found to have low predictive yield (vascular injury 4.1% and 2.1%, respectively). The above statistics were based on the initial radiologist report and Emergency Department findings. After retrospective review, 3 Grade 1 BIFFL vascular injuries were identified (2.1%), with one false negative case (0.7%). Conclusion Performing CTA of the neck after acute strangulation injury rarely identifies clinically significant findings, with vascular injuries proving exceedingly rare. As positive vascular injury could not be clinically predicted by history and physical examination, prospective validation of a clinical prediction rule in this population is warranted.

Bronchial arterial embolization using a gelatin sponge for hemoptysis from pulmonary aspergilloma: comparison with other pulmonary diseases Abstract Purpose To evaluate the clinical outcomes of bronchial artery embolization (BAE) using a gelatin sponge for hemoptysis from pulmonary aspergilloma and compare them with treatment outcomes for hemoptysis from other diseases. Methods Fifty-two patients underwent BAE using a gelatin sponge. The etiology of hemoptysis was pulmonary aspergilloma in 8 (PA group) and other diseases in 44 (control group). The technical success rate, clinical success rate, hemoptysis-free rate, and complication rate were compared between the PA group and control group. Technical success was defined as the complete cessation of the targeted feeding artery as confirmed by digital subtraction angiography, and clinical success as the cessation of hemoptysis within 24 h of BAE. Recurrent hemoptysis was defined as a single or multiple episodes of hemoptysis causing > 30 ml of bleeding per day. Results Technical and clinical success rates were 100% in both groups. Hemoptysis-free rates were 85% at 6 months and 72% at 12–60 months in the control group, and 38% at 6–12 months and 25% thereafter in the PA group (P = 0.0009). No complications were observed following BAE in any case in the two groups. Conclusion BAE using a gelatin sponge may not be effective for hemoptysis from pulmonary aspergilloma.

Trapezium fracture: a common clinical mimic of scaphoid fracture Abstract Purpose Fractures of the trapezium are rarely diagnosed on plain radiographs after acute wrist trauma. High-resolution cross-sectional imaging identifies fractures of the trapezium as the most common radiographically occult carpal bone fracture. We review the fracture frequency, mechanisms and patterns of trapezium fractures. Methods Cone beam CT was performed in patients with suspected radiographically occult radiocarpal fracture following acute injury. The frequency of carpal bone fractures was assessed and compared. Results Ninety-three radiographically occult wrist fractures were identified in 166 patients with acute trauma and negative radiographs. The trapezium was the most frequently fractured carpal bone, making up 20.4% of wrist fractures. Seventy-nine percent of trapezium fractures involved the volar ridge. The scaphoid was the clinically suspected fractured bone at initial assessment in 84% of patients with trapezium fractures. Conclusion Fractures of the trapezium in acute wrist trauma are much more common than described in the literature. If initial radiographs are negative, a fracture of the trapezium is more likely to be present than one of the scaphoid, despite high levels of clinical suspicion for scaphoid injuries. Awareness of the types and mechanisms of trapezium fracture is important. Cross-sectional imaging should be considered in all cases of post-traumatic wrist pain with negative radiographs.

The utility of whole spine survey MRI in blunt trauma patients sustaining single level or contiguous spinal fractures Abstract Purpose To determine the utility of obtaining whole-spine survey MRI after a whole-spine CT diagnoses single level or contiguous fractures. Methods A retrospective search from 2015 to 2017 was performed using an institutional PACS database for consecutive patients who sustained spinal fractures from blunt injury. Only patients who received whole-spine CT followed by whole-spine MRI were included in the study. All cases had sagittal T2-weighted and Short TI (Tau) inversion recovery (STIR) imaging of the entire spine with additional T1 and T2-weighted axial imaging covering the known injury. Reports from the whole-spine CTs were compared to the reports of the whole-spine MRI to determine if additional bony and soft tissue injury were identified on subsequent MRI. Results A total of 156 patients met the inclusion criteria, with an average age of 59.5 ± 20.6 years. Twenty-nine patients (18.5%) had a whole-spine MRI that demonstrated an additional bony ± soft tissue injury. A 95.1% of the additional injuries were osseous contusions or vertebral body compression fractures without significant loss of height. The distance between the original injury on CT and the additional injury on MR ranged from 1 to 13 vertebrae. A 82.8% of the additional injuries occurred within 1 to 8 vertebrae levels of the primary injury and most commonly in the thoracic spine. Conclusions Most additional bony injuries detected on MRI are bone contusions and mild compression fractures, which are unlikely to alter management. However, if screening MRI is performed for additional bony injuries, we posit that a targeted regional spinal MRI is adequate.

Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department Abstract Purpose To retrospectively evaluate the utility of biphasic multi-detector computed tomography (MDCT) with arterial and portal venous phases for the detection of suspected acute mesenteric ischemia (AMI) in emergency department (ED) patients compared to limited surgical confirmation. Methods A research ethics board (REB)-approved retrospective review of all consecutive adult patients who underwent an emergency biphasic 64-MDCT examination of the abdomen and pelvis due to clinical suspicion for AMI over a 5-year period at a single tertiary-care institution was performed. Patients who underwent biphasic 64-MDCT scans performed for any clinical concern other than suspected acute mesenteric ischemia were excluded. Specifically, reported vascular and bowel findings were used to establish occlusive arterial, venous, and non-occlusive MDCT findings of AMI. Correlation was made with surgical findings in operatively managed patients and with serum lactate values preceding imaging assessment. Diagnostic yield and positive predictive value calculations were performed. Results Two hundred and twenty-five patients underwent MDCT for suspected occlusive AMI between 10 Jan 2011 and 31Jul 2016. Of these, 200 patients were negative for AMI and 25 patients (mean age 73.5 years; age range 48 to 94 years; 13 men and 12 women) had MDCT findings positive for bowel ischemia (yield of 11.1%). On MDCT, 18/25 (72%) had an occlusive arterial etiology for AMI, 2/25 (8%) had an occlusive venous etiology, and 5/25 (20%) had non-occlusive AMI. Twenty of 25 (80%) patients with positive MDCT findings of AMI also had an elevated serum lactate level, including 14/18 (77.8%) patients with arterial occlusive AMI on MDCT, 2/2 (100%) with venous-occlusive AMI on MDCT, and 4/5 (80%) with non-occlusive AMI on MDCT. Correlation with surgical findings led to a positive predictive value (PPV) of biphasic MDCT for surgically proven all-cause occlusive ischemia of 92.9%. Further substratification revealed PPVs of arterial and venous-occlusive ischemia of 85.7% and 7.1%, respectively. Of the 225 patients MDCT-positive for AMI, 213 had pre-imaging serum lactate assessments. Of 188 patients MDCT-negative for AMI, 85 patients had elevated serum lactate (45.2%). Twenty of the 25 patients with positive MDCT findings of AMI (80%) also had an elevated serum lactate level, including 14/18 (77.8%) patients with arterial occlusive AMI on MDCT, 2/2 (100%) with venous-occlusive AMI on MDCT, and 4/5 (80%) with non-occlusive AMI on MDCT. Conclusion Emergent biphasic MDCT demonstrated low but non-trivial yield (11.1%) for the depiction of suspected acute mesenteric ischemia but was particularly low for occlusive venous AMI (0.9%). The relationship between serum lactate elevation and positive MDCT findings of AMI in our study conforms to prior work and cautiously suggests value in routine serum lactate assessment preceding imaging for patient prioritization.

Blunt chest trauma: classification and management Abstract Blunt chest wall injuries are a significant cause of mortality and morbidity in trauma patients. Accurate identification and description of chest wall injuries by the radiologist can aid in guiding proper patient management. The American Association for the Surgery of Trauma (AAST) has devised a classification system based on severity. This article describes the features of each injury grade according to the AAST injury scale and discusses the implications for management. Additionally, common mechanisms of blunt chest trauma and multimodal imaging techniques are discussed.

Non-traumatic subdural hemorrhage: beware of ruptured intracranial aneurysm Abstract Acute subdural hemorrhage (SDH) is commonly encountered by emergency radiologists in the setting of trauma. When history or imaging evidence of trauma is absent, the differential diagnosis for SDH should be expanded. Intracranial aneurysm rupture is a rare and underrecognized cause of SDH which may present without concurrent subarachnoid hemorrhage. The mechanism of aneurysmal SDH is controversial, but understanding the anatomic microenvironment of the aneurysm provides insight and clarifies aneurysm features predisposing to subdural compartment rupture. Aneurysmal SDH is a neurosurgical emergency and its treatment strategies differ from traumatic SDH. Outcomes are poor if treatment is delayed; thus, radiologists play a central role in recognizing this uncommon but potentially devastating complication of aneurysm rupture. The goal of this article is to familiarize radiologists with clinical and imaging characteristics of aneurysmal SDH and review pertinent anatomy, risk factors, and potential etiologies. Aneurysmal rupture can easily be overlooked in the routine workup of atraumatic SDH, and radiologists must know when to recommend vascular imaging to avoid the catastrophic consequences of a missed diagnosis.