Segmental Bowel Hypoenhancement on CT Predicts Ischemic Mesenteric Laceration After Blunt Trauma.

OBJECTIVE. The objectives of this study were to examine the performance of CT in the diagnosis of ischemic mesenteric laceration after blunt trauma and to assess the predictive value of various CT signs for this injury. MATERIALS AND METHODS. In this retrospective study, consecutive patients with bowel and mesenteric injury diagnosed by CT or surgery from January 2011 through December 2016 were analyzed. Two radiologists evaluated CT images for nine signs of bowel injury. The outcome evaluated was ischemic mesenteric laceration. Univariable analysis followed by logistic regression was performed. RESULTS. The study included 147 patients (96 men and 51 women; median age, 35 years; age range, 23-52 years). Thirty-three patients had surgically confirmed ischemic mesenteric lacerations. CT signs that correlated with ischemic mesenteric laceration were abdominal wall injury, mesenteric contusion, free fluid, segmental bowel hypoenhancement, and bowel hyperenhancement adjacent to a hypoenhancing segment. The regression model developed after inclusion of clinical variables identified two predictors: segmental bowel hypoenhancement (adjusted odds ratio, 22.9 [95% CI, 7.9-66.2; p < .001] for reviewer 1 and 20.7 [95% CI, 7.2-59.0; p < .001] for reviewer 2) and abdominal wall injury (adjusted odds ratio, 5.26 [95% CI, 1.7-15.9; p = .003] for reviewer 1 and 5.3 [95% CI, 1.9-15.0; p = .002] for reviewer 2), which yielded an AUC of 0.87 for predicting injury. For reviewer 1 and reviewer 2, the sensitivities of CT in detecting the injury were 72.3% (95% CI, 54.5-86.7%) and 78.8% (95% CI, 61.0-91.0%), respectively, whereas the specificities were 94.7% (95% CI, 88.9-98.0%), and 92.1% (95% CI, 85.5-96.3%), respectively. CONCLUSION. CT has limited sensitivity but good specificity for detecting ischemic mesenteric laceration, with segmental bowel hypoenhancement considered the most predictive imaging sign.

A virtual emergency: learning lessons from remote medical student education during the COVID-19 pandemic.

PURPOSE: The COVID-19 pandemic resulted in the cancelation of traditional on-site clinical rotations for medical students across the country. Radiology educators have had to rapidly adapt to a new, virtual educational landscape. We describe our experience restructuring a Trauma and Emergency Radiology Elective to an online format and present survey data obtained from students who completed the course. METHODS: This elective is a 4-week course offered to third and fourth year medical students at a large Level 1 Trauma Center. Changes to the traditional rotation included assigning an increased number of self-study educational resources, independent review of unknown cases using a virtual workstation, and online interactive conferences. At the conclusion of each block, students were asked to complete post-course feedback surveys. RESULTS: Thirteen students enrolled in this online course; 92% submitted post-course surveys. Students strongly agreed that the course was clinically relevant, with accessible, engaging material (average score, 4.92/5), and 91.7% of students were very likely to recommend this rotation to others. Students reported improved post-course confidence in ordering and interpreting imaging studies. A majority (60%) of students who had previously taken an on-site course would have preferred a course that combined traditional and online learning elements. CONCLUSIONS: The success of our online rotation highlights the merits of self-directed learning and flipped-classroom techniques. Many of the principles incorporated into this course could be applied and/or modified to increase medical student engagement when students return to the hospital.

An Automated Deep Learning Method for Tile AO/OTA Pelvic Fracture Severity Grading from Trauma whole-Body CT.

Admission trauma whole-body CT is routinely employed as a first-line diagnostic tool for characterizing pelvic fracture severity. Tile AO/OTA grade based on the presence or absence of rotational and translational instability corresponds with need for interventions including massive transfusion and angioembolization. An automated method could be highly beneficial for point of care triage in this critical time-sensitive setting. A dataset of 373 trauma whole-body CTs collected from two busy level 1 trauma centers with consensus Tile AO/OTA grading by three trauma radiologists was used to train and test a triplanar parallel concatenated network incorporating orthogonal full-thickness multiplanar reformat (MPR) views as input with a ResNeXt-50 backbone. Input pelvic images were first derived using an automated registration and cropping technique. Performance of the network for classification of rotational and translational instability was compared with that of (1) an analogous triplanar architecture incorporating an LSTM RNN network, (2) a previously described 3D autoencoder-based method, and (3) grading by a fourth independent blinded radiologist with trauma expertise. Confusion matrix results were derived, anchored to peak Matthews correlation coefficient (MCC). Associations with clinical outcomes were determined using Fisher's exact test. The triplanar parallel concatenated method had the highest accuracies for discriminating translational and rotational instability (85% and 74%, respectively), with specificity, recall, and F1 score of 93.4%, 56.5%, and 0.63 for translational instability and 71.7%, 75.7%, and 0.77 for rotational instability. Accuracy of this method was equivalent to the single radiologist read for rotational instability (74.0% versus 76.7%, p = 0.40), but significantly higher for translational instability (85.0% versus 75.1, p = 0.0007). Mean inference time was < 0.1 s per test image. Translational instability determined with this method was associated with need for angioembolization and massive transfusion (p = 0.002-0.008). Saliency maps demonstrated that the network focused on the sacroiliac complex and pubic symphysis, in keeping with the AO/OTA grading paradigm. A multiview concatenated deep network leveraging 3D information from orthogonal thick-MPR images predicted rotationally and translationally unstable pelvic fractures with accuracy comparable to an independent reader with trauma radiology expertise. Model output demonstrated significant association with key clinical outcomes.

CT Prediction Model for Major Arterial Injury after Blunt Pelvic Ring Disruption.

Purpose To develop and test a computed tomography (CT)-based predictive model for major arterial injury after blunt pelvic ring disruptions that incorporates semiautomated pelvic hematoma volume quantification. Materials and Methods A multivariable logistic regression model was developed in patients with blunt pelvic ring disruptions who underwent arterial phase abdominopelvic CT before angiography from 2008 to 2013. Arterial injury at angiography requiring transarterial embolization (TAE) served as the outcome. Areas under the receiver operating characteristic (ROC) curve (AUCs) for the model and for two trauma radiologists were compared in a validation cohort of 36 patients from 2013 to 2015 by using the Hanley-McNeil method. Hematoma volume cutoffs for predicting the need for TAE and probability cutoffs for the secondary outcome of mortality not resulting from closed head injuries were determined by using ROC analysis. Correlation between hematoma volume and transfusion was assessed by using the Pearson coefficient. Results Independent predictor variables included hematoma volume, intravenous contrast material extravasation, atherosclerosis, rotational instability, and obturator ring fracture. In the validation cohort, the model (AUC, 0.78) had similar performance to reviewers (AUC, 0.69-0.72; P = .40-.80). A hematoma volume cutoff of 433 mL had a positive predictive value of 87%-100% for predicting major arterial injury requiring TAE. Hematoma volumes correlated with units of packed red blood cells transfused (r = 0.34-0.57; P = .0002-.0003). Predicted probabilities of 0.64 or less had a negative predictive value of 100% for excluding mortality not resulting from closed head injuries. Conclusion A logistic regression model incorporating semiautomated hematoma volume segmentation produced objective probability estimates of major arterial injury. Hematoma volumes correlated with 48-hour transfusion requirement, and low predicted probabilities excluded mortality from causes other than closed head injury. © RSNA, 2018 Online supplemental material is available for this article.

Penetrating Colorectal Injuries: Diagnostic Performance of Multidetector CT with Trajectography.

Purpose To determine the diagnostic performance of multidetector computed tomography (CT) with trajectography for penetrating colorectal injuries. Materials and Methods This institutional review board-approved and HIPAA-compliant study was a 6-year blinded retrospective review by two independent readers of 182 consecutive patients who preoperatively underwent 40- or 64-row multidetector CT for penetrating torso trauma below the diaphragm and had surgically confirmed findings. Colorectal perforation was present in 42 patients. Trajectory analysis with postprocessing software was used for all studies. Additional signs evaluated were rectal contrast agent leak, collections of extruded fecal material, mural defect, wall thickening, abnormal enhancement, free fluid or stranding, and free air. The quality of the colorectal contrast agent administration was recorded. Sensitivity, specificity, predictive values, areas under the receiver operating characteristic curves (AUCs), and Cohen κ were determined. Results In patients with rectal contrast agent administration (n = 151), AUCs were 0.90-0.91, which indicated excellent accuracy. Trajectory was sensitive (88%-91%). For single wounds (n = 104), sensitivity of trajectory was 96% for both readers, but was only 80% for multiple wounds (n = 47). Contrast agent leak was highly specific (96%-98%), but insensitive (42%-46%). Improved diagnostic performance was observed in patients with poor colonic distension or opacification. Accuracy remained high (AUC, 0.86-0.99) in the group without rectal contrast agent administration (n = 31). Conclusion Trajectory had excellent sensitivity, while rectal contrast agent leak was specific but insensitive. Sensitivity of trajectory was lower for multiple wounds. Accuracy remained high in patients without rectal contrast agent administration. © RSNA, 2016.

Diagnostic accuracy of triple-contrast multi-detector computed tomography for detection of penetrating gastrointestinal injury: a prospective study.

PURPOSE: Neither the performance of CT in diagnosing penetrating gastrointestinal injury nor its ability to discriminate patients requiring either observation or surgery has been determined. MATERIALS AND METHODS: This was a prospective, single-institutional observational study of patients with penetrating injury to the torso who underwent CT. Based on CT signs, reviewers determined the presence of a gastrointestinal injury and the need for surgery or observation. The primary outcome measures were operative findings and clinical follow-up. CT results were compared with the primary outcome measures. RESULTS: Of one hundred and seventy-one patients (72 gunshot wounds, 99 stab wounds; age range, 18-57 years; median age, 28 years) with penetrating torso trauma who underwent CT, 45 % were followed by an operation and 55 % by clinical follow up. Thirty-five patients had a gastrointestinal injury at surgery. The sensitivity, specificity, and accuracy of CT for diagnosing a gastrointestinal injury for all patients were each 91 %, and for predicting the need for surgery, they were 94 %, 93 %, 93 %, respectively. Among the 3 % of patients who failed observation, 1 % had a gastrointestinal injury. CONCLUSION: CT is a useful technique to diagnose gastrointestinal injury following penetrating torso injury. CT can help discriminate patients requiring observation or surgery. KEY POINTS: • The most sensitive sign is wound tract extending up to gastrointestinal wall. • The most accurate sign is gastrointestinal wall thickening. • Triple-contrast CT is a useful technique to diagnose gastrointestinal injury. • Triple-contrast CT helps to discriminate patients requiring observation and surgery.

Will the Real SCIWORA Please Stand Up? Exploring Clinicoradiologic Mismatch in Closed Spinal Cord Injuries.

OBJECTIVE: This article aims to familiarize radiologists with the terms used to describe clinicoradiologic mismatch in blunt spinal cord injuries, and also assesses MRI findings and their prognostic value for both pediatric and adult patients. CONCLUSION: Knowledge of the lexicon of spinal cord injury without radiographic abnormality, the spectrum of MRI findings, and imaging predictors of outcome can help render a precise imaging diagnosis and can provide evidence-based prognostic information.

Vascular Injuries to the Neck After Penetrating Trauma: Diagnostic Performance of 40- and 64-MDCT Angiography.

OBJECTIVE: The purposes of this study were to assess the diagnostic performance of 40- and 64-MDCT angiography with digital subtraction angiography as the reference standard in the detection of arterial injuries in patients at high risk after penetrating neck trauma and to perform a separate analysis of injuries to the external carotid artery. MATERIALS AND METHODS: In a retrospective evaluation of 53 sets of angiograms from 51 patients with penetrating neck injury, three reviewers unaware of the digital subtraction angiographic findings reviewed the CT angiographic (CTA) images to discern the presence or absence of arterial injuries. Sensitivity and specificity of CTA were calculated per injury, and a separate analysis of external carotid artery injuries was performed. RESULTS: Sensitivity of CTA for detecting arterial injuries ranged from 75.7% (95% CI, 62.3-86.9%) to 82.2% (95% CI, 69.5-92.1%). Specificity ranged from 96.4% (95% CI, 94.0-98.4%) to 98.4% (95% CI, 96.0-100%). CTA was highly sensitive for detection of the subgroup of injuries involving the large-caliber vessels that contribute to cerebral circulation. These sensitivities ranged from 92.8% (95% CI, 66-98.8%) to 100% (95% CI, 76.6-100%) for internal carotid artery injuries and from 88.9% (95% CI, 65.2-98.3%) to 94.4% (95% CI, 72.6-99.0%) for vertebral artery injuries. In contrast, sensitivity of CTA was limited for external carotid artery injuries, ranging from 63.4% (95% CI, 45.5-79.5%) to 70.0% (95% CI, 52.0-85.0%). CONCLUSION: CTA can be used for initial evaluation and may help guide management decisions if an external carotid artery injury is detected. Negative findings should not preclude close clinical follow-up, repeat CTA evaluation, or, in the presence of high suspicion of arterial injury due to clinical findings or wound trajectory, evaluation with digital subtraction angiography.

Optimizing trauma multidetector CT protocol for blunt splenic injury: need for arterial and portal venous phase scans.

PURPOSE: To retrospectively compare the diagnostic performance of arterial, portal venous, and dual-phase computed tomography (CT) for blunt traumatic splenic injury. MATERIALS AND METHODS: Informed consent was waived for this institutional review board-approved, HIPAA-compliant study. Retrospective record review identified 120 blunt trauma patients (87 male [72.5%] 33 female [27.5%]; age range, 18-94 years) who had undergone dual-phase abdominal CT within 5 years, including 30 without splenic injury, 30 with parenchymal injury only, 30 with splenic active bleeding, and 30 with intrasplenic pseudoaneurysm. Six radiologists each performed blinded review of 20 different cases, and scored the presence of pseudoaneurysm, active bleeding, parenchymal injury, and hematoma; 20 cases were interpreted by all radiologists. Data analysis included calculation of diagnostic performance measures with confidence intervals, areas under receiver operating characteristic curves, and interobserver agreement/variability. RESULTS: For intrasplenic pseudoaneurysm, arterial phase imaging was more sensitive (70% [21 of 30] vs 17% [five of 30]; P < .0002) and more accurate (87% [78 of 90] vs 72% [65 of 90]; P = .0165) than portal venous phase imaging. For active bleeding, arterial phase imaging was less sensitive (70% [21 of 30] vs 93% [28 of 30]; P = .0195) and less accurate (89% [80 of 90] vs 98% [88 of 90]; P = .0168) than portal venous phase imaging. For parenchymal injury, arterial phase CT was less sensitive (76% [68 of 90] vs 93% [84 of 90]; P = .001) and less accurate (81% [nine of 120] vs 95% [114 of 120]; P = .0008) than portal venous phase CT. For all injuries, dual-phase review was equivalent to or better than single-phase review. CONCLUSION: For CT evaluation of blunt splenic injury, arterial phase is superior to portal venous phase imaging for pseudoaneurysm but inferior for active bleeding and parenchymal disruption; dual-phase CT provides optimal overall performance.

Radiology Medical Student Education 2020: Surveys of the Alliance of Medical Student Educators in Radiology and Medical Students.

RATIONALE AND OBJECTIVES: The coronavirus disease 2019 (COVID-19) pandemic has resulted in significant changes to medical student education by disrupting clinical rotations, licensing exams, and residency applications. To evaluate the pandemic's impact and required modifications of radiology medical student courses, the authors developed and administered surveys to Alliance of Medical Student Educators in Radiology (AMSER) faculty and enrolled medical students. The surveys requested feedback and insight about respondents' experiences and innovations. MATERIALS AND METHODS: Anonymous twenty-question and seventeen-question surveys about the pandemic's impact on medical student education were distributed via email to AMSER members and medical students. The surveys consisted of multiple choice, ranking, Likert scale, and open-ended questions. Differences in the Likert score agreement was performed using one-sided Wilcoxon-Mann-Whitney tests. Survey data were collected using SurveyMonkey (San Mateo, California). This study was IRB exempt. RESULTS: The AMSER survey indicated 96% of institutions cancelled medical student courses and 92% resumed with virtual courses, typically general radiology. A total of 64% of faculty enjoyed online teaching, although 82% preferred on-site courses. A total of 62% of students felt an online radiology course was an excellent alternative to an on-site rotation, although 27% disagreed. A total of 69% of students who completed both on-site and online courses preferred the on-site format. Survey-reported innovations and free response comments have been collated as educational resources. CONCLUSION: Faculty were able to adapt radiology courses to the online environment utilizing interactive lectures, self-directed learning, flipped classroom sessions, and virtual readouts, which were effective for student respondents. Hybrid rotations with on-site and online elements may offer the best of both worlds.

Postmortem computed tomography as an adjunct to autopsy for analyzing fatal motor vehicle crash injuries: results of a pilot study.

BACKGROUND: Detailed fatal injury data after fatal motor vehicle crashes (MVC) are necessary to improve occupant safety and promote injury prevention. Autopsy remains the principle source of detailed fatal injury data. However, procedure rates are declining because of a range of technical, ethical, and religious concerns. Postmortem computed tomography (PMCT) is a potential alternative or adjunct to autopsy which is increasingly used by forensic researchers. However, there are only limited data regarding the utility of PMCT for analysis of fatal MVC injuries. METHODS: We performed whole body PMCT and autopsy on six subjects fatally injured in MVC in a single county in Michigan. All injuries detected by either method were coded using the Abbreviated Injury Scale (AIS). Severe injuries, defined as AIS 3 or higher (AIS 3+), were tallied for each forensic procedure to allow a comparison of relative diagnostic performance. RESULTS: A total of 46 AIS 3+ injuries were identified by autopsy and PMCT for these cases. The addition of PMCT to autopsy increased overall detection of AIS 3+ injuries (all types) by 28%. PMCT detected 27% more AIS 3+ skeletal injuries than autopsy but 25% less soft tissue injuries. CONCLUSIONS: Use of PMCT improves the detection of AIS 3+ injuries after fatal MVC compared with isolated use of autopsy and also produces a highly detailed permanent objective record. PMCT appears to improve detection of skeletal injury compared with autopsy but is less sensitive than autopsy for the detection of AIS 3+ soft tissue injuries. Neither autopsy nor PMCT identified all AIS 3+ injuries revealed by the combination of the two methodologies. This suggests that PMCT should be used as an adjunct to autopsy rather than a replacement whenever feasible.

Vascular complications of penetrating brain injury: comparison of helical CT angiography and conventional angiography.

OBJECT: The authors conducted a study to compare the sensitivity and specificity of helical CT angiography (CTA) and digital subtraction angiography (DSA) in detecting intracranial arterial injuries after penetrating traumatic brain injury (PTBI). METHODS: In a retrospective evaluation of 48 sets of angiograms from 45 consecutive patients with PTBI, 3 readers unaware of the DSA findings reviewed the CTA images to determine the presence or absence of arterial injuries. A fourth reader reviewed all the disagreements and decided among the 3 interpretations. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CTA were calculated on a per-injury basis and in a subpopulation of patients with traumatic intracranial aneurysms (TICAs). RESULTS: Sensitivity of CTA for detecting arterial injuries was 72.7% (95% CI 49.8%-89.3%); specificity, 93.5% (95% CI 78.6%-99.2%); PPV, 88.9% (95% CI 65.3%-98.6%); and NPV, 82.9% (95% CI 66.4%-93.4%). All 7 TICAs were correctly identified by CTA. Sensitivity, specificity, PPV, and NPV of CTA in detecting TICAs were 100%. To compare agreement with DSA, the standard of reference, confidence scores categorized as low, intermediate, and high probability yielded an overall effectiveness of 77.8% (95% CI 71.8%-82.9%). CONCLUSIONS: Computed tomography angiography had limited overall sensitivity in detecting arterial injuries in patients with PTBI. However, it was accurate in identifying TICAs, a subgroup of injuries usually managed by either surgical or endovascular approaches, and non-TICA injuries involving the first-order branches of intracranial arteries.

Splenic trauma: what is new?

Evaluation for splenic injury is an important component of patient assessment after blunt abdominal trauma. Key imaging modalities include ultrasound, particularly for rapid identification of hemoperitoneum, and computed tomography (CT), which permits a more detailed and accurate determination of splenic integrity. Specific findings at contrast-enhanced multidetector CT (MDCT) should prompt the consideration of catheter angiography with arterial embolization as an adjunct to nonsurgical management. This article reviews the roles of imaging in the management of splenic trauma, illustrates the MDCT appearance of various splenic injuries, and discusses imaging-based indications for operative and angiographic intervention.