Scott D. Steenburg

Acute Traumatic Aortic Injury: Imaging Evaluation and Management

Despite recent advances in prehospital care, multidetector computed tomographic (CT) technology, and rapid definitive therapy, trauma to the aorta continues to be a substantial source of morbidity and mortality in patients with blunt trauma. The imaging evaluation of acute aortic injuries has undergone radical change over the past decade, mostly due to the advent of multidetector CT. Regardless of recent technologic advances, imaging of the aorta in the trauma setting remains a multimodality imaging practice, and thus broad knowledge by the radiologist is essential. Likewise, the therapy for acute aortic injuries has changed substantially. Though open surgical repair continues to be the mainstay of therapy, percutaneous endovascular repair is becoming commonplace in many trauma centers. Here, the historical and current status of imaging and therapy of acute traumatic aortic injuries will be reviewed.

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.

Acute traumatic thoracic aortic injuries: Experience with 64-MDCT

OBJECTIVE At some institutions, catheter angiography is used for confirmation of aortic injuries and equivocal MDCT findings. Because of the speed and efficiency of 64-MDCT, we believe that diagnostic catheter angiography may be obsolete. The purpose of this study was to review our experience with 64-MDCT in the evaluation of acute traumatic aortic injury (ATAI). MATERIALS AND METHODS The trauma registry at a level 1 trauma center was reviewed to find cases of ATAI occurring between March 1, 2005, and July 31, 2007. MDCT images were correlated with transcatheter angiograms when obtained. Surgical and clinical reports were reviewed to confirm abnormal and normal findings and the stability of the conditions of patients undergoing conservative treatment. RESULTS After level 1 or level 2 trauma, 1,344 patients underwent contrast-enhanced 64-MDCT. Twenty-four patients (1.79%) were found to have 25 aortic injuries. All patients had direct MDCT signs of ATAI. Ten catheter angiograms were obtained after MDCT. The presence of direct signs was confirmed in three cases. In five cases, indirect signs were found to be normal findings. In two cases, the findings remained equivocal after MDCT and conventional angiography. Fourteen patients underwent surgical repair of the aorta, six underwent conservative management, and four patients died of other injuries. No patient with equivocal or indirect findings needed surgical repair. The sensitivity of 64-MDCT was 96.0%; specificity, 99.8%; positive predictive value, 92.3%; negative predictive value, 99.9%; and accuracy, 99.8%. CONCLUSION Direct signs of ATAI on contrast-enhanced 64-MDCT scans do not have to be confirmed with catheter angiography. In our population, diagnostic transcatheter angiography was of limited value for clarifying equivocal or indirect MDCT findings.

Multi-detector computed tomography findings of atypical blunt traumatic aortic injuries: A pictorial review

Traumatic injuries to the aorta are a significant source of morbidity and mortality in trauma patients, which highlights the importance of rapid diagnosis and treatment. Multi-detector row computed tomography has become the primary imaging modality for the imaging assessment of the polytrauma patient because it is fast, noninvasive, and the data sets can be used to create tailored multi-planar reformatted images that optimally display the location and morphology of aortic trauma and its relationship to adjacent structures. Although the classic location of blunt injury to the aorta occurs just distal to the left subclavian artery, aortic injuries may occur at any location along the aorta and in any patient population. Radiologists should be prepared to evaluate these types of injuries in nontraditional planes that are tailored to each examination and to present the data to clinicians using commercially available 3D software for purposes of surgical planning. Here, we review in pictorial form atypical aortic injuries with emphasis on multi-planar reformations.

Blunt traumatic injury of the ascending aorta: multidetector CT findings in two cases.

Blunt ascending aortic injuries are rare in clinical practice. We have encountered two types of injuries to the ascending aorta with multidetector computed tomography: (1) a tear of the wall of the aortic root with a contained rupture and associated hemopericardium and (2) a tear at the level of the aortic valve cusp without associated hemopericardium. In reviewing our experience with aortic trauma at our institution under IRB waiver of consent, we encountered two cases of ascending aortic rupture that illustrate the two injury patterns. We present these two cases to alert radiologists to the multidetector computed tomographic findings of this life-threatening injury.

Facial Fracture in the Setting of Whole-Body CT for Trauma: Incidence and Clinical Predictors

OBJECTIVE The objective of our study was to identify the incidence and clinical predictors of facial fracture in the setting of whole-body MDCT for trauma. MATERIALS AND METHODS The clinical data from the electronic medical records, including the final radiology reports, of 486 consecutive patients who underwent MDCT for trauma (head, cervical spine, chest, abdomen, and pelvis examinations) with dedicated maxillofacial reconstructions from October 1, 2011, to July 31, 2013, were studied. The clinical variables were compared between cohorts of patients with and those without facial fracture. The two-sample t test was used to compare continuous variables, and the Fisher exact test was used to compare categoric variables. RESULTS Two hundred sixteen (44.4%) patients had at least one fracture on the dedicated maxillofacial CT examinations, 215 of whom had facial physical examination findings (sensitivity = 99.5%). Of the 28 patients without documented physical examination findings, 27 did not have a facial fracture (negative predictive value = 96.4%). Statistically significant differences were found between positive and negative cases of facial fracture in patients with a Glasgow coma scale (GCS) score of 8 or less (p < 0.0001), an injury severity score of 16 or greater (p < 0.0001), acute alcohol intoxication according to blood alcohol concentration (BAC) (p = 0.0387), intubation at presentation (p < 0.0001), positive physical examination findings (p < 0.0001), and loss of consciousness (p = 0.0364). Falls from a height greater than standing height and open-vehicle collisions had the highest fracture rates (80.0% and 58.3%, respectively). CONCLUSION A negative finding at facial physical examination reliably excluded fracture. Clinical variables positively associated with facial fracture included the following: GCS score of 8 or less, ISS of 16 or greater, alcohol intoxication according to BAC, intubation at presentation, loss of consciousness, and the presence of abnormal facial findings at physical examination.

Magnetic resonance imaging of traumatic brain injury: a pictorial review

Traumatic brain injury (TBI) is a significant source of major morbidity and mortality in blunt trauma patients. Computed tomography (CT) is the primary imaging modality of choice for patients with potential brain injury in the acute setting, with magnetic resonance imaging (MRI) playing a role in evaluating equivocal CT findings and may help with determining long-term prognosis and recovery. MRI is being utilized more commonly in the acute and subacute setting of TBI; therefore, radiologists should be familiar with the MRI appearance of the various manifestations of TBI. Here, we review the imaging of common intracranial injuries with illustrative cases comparing CT and MRI.

JOURNAL CLUB: Incidence of Urinary Leak and Diagnostic Yield of Excretory Phase CT in the Setting of Renal Trauma

OBJECTIVE The purpose of this article is to calculate the incidence of urinary leak, at both admission and delayed presentation, in the setting of blunt or penetrating renal trauma, and to determine the diagnostic yield of 5-minute excretory phase images on admission CT. MATERIALS AND METHODS Renal injuries were retrospectively identified from the trauma registry at an urban level I trauma center over a 6-year period. Follow-up imaging and clinical and surgical notes were reviewed and served as the aggregate reference standard. The total incidence of urinary leak, diagnostic yield of 5-minute-delayed admission CT scan, and the incidence of missed urinary leak not identified on admission 5-minute-delayed scan were calculated. RESULTS There were a total of 431 renal injuries in 413 patients, of whom 201 patients (48.7%, including 60.8% of patients with grade IV or V injuries) underwent delayed phase imaging at admission, yielding 25 patients with 26 urinary leaks (all grade IV or V injuries). The incidence of urinary leak in grade IV or V injuries was 26.8%. One patient had a delayed diagnosis of urinary leak 36 hours after the initial CT scan, which did not show a urinary leak (0.23% of the total, or 1.0% of all high-grade renal injuries). CONCLUSION The incidence of urinary leak after blunt or penetrating renal trauma was 6.1% and was seen in 26.8% of grade IV and V injuries. Admission excretory phase CT identified urinary leaks in 96% of patients. The incidence of delayed diagnosis of urinary leak is low.

Is the new ACR-SPR practice guideline for addition of oblique views of the ribs to the skeletal survey for child abuse justified?

OBJECTIVE The purpose of our study was to determine whether adding oblique bilateral rib radiography to the skeletal survey for child abuse significantly increases detection of the number of rib fractures. MATERIALS AND METHODS We identified all patients under 2 years old who underwent a skeletal survey for suspected child abuse from January 2003 through July 2011 and who had at least one rib fracture. These patients were age-matched with control subjects without fractures. Two randomized radiographic series of the ribs were performed, one containing two views (anteroposterior and lateral) and another with four views (added right and left oblique). Three fellowship-trained radiologists (two in pediatrics and one in trauma) blinded to original reports independently evaluated the series using a Likert scale of 1 (no fracture) to 5 (definite fracture). We analyzed the following: sensitivity and specificity of the two-view series for detection of any rib fracture and for location (using the four-view series as the reference standard), interobserver variability, and confidence level. RESULTS We identified 212 patients (106 with one or more fractures and 106 without). The sensitivity and specificity of the two-view series were 81% and 91%, respectively. Sensitivity and specificity for detection of posterior rib fractures were 74% and 92%, respectively. There was good agreement between observers for detection of rib fractures in both series (average kappa values of 0.70 and 0.78 for two-views and four-views, respectively). Confidence significantly increased for four-views. CONCLUSION Adding bilateral oblique rib radiographs to the skeletal survey results in increased rib fracture detection and increased confidence of readers.

Tissue damage volume predicts organ dysfunction and inflammation after injury

BACKGROUND Multiply injured patients (MIPs) are at risk to develop multiple-organ failure (MOF) and prolonged systemic inflammation response syndrome (SIRS). It is difficult to predict which MIPs are at the highest risk to develop these complications. We have developed a novel method that quantifies the distribution and physical magnitude of all injuries identified on admission computed tomography scanning called the Tissue Damage Volume (TDV) score. We explored how individualized TDV scores corresponded to MOF and SIRS. MATERIALS AND METHODS A retrospective study on 74 MIPs measured mechanical TDV by calculating injury volumes on admission computed tomography scans of all injuries in the head/neck, chest, abdomen, and pelvis. Regional and total TDV scores were compared between patients that did or did not develop MOF or sustained SIRS. The magnitude of organ dysfunction was also stratified by the magnitude of TDV. RESULTS Mean total and pelvic TDV scores were significantly increased in patients who developed MOF. Mean total, chest, and abdominal TDV scores were increased in patients who developed sustained SIRS. The magnitude of organ dysfunction was significantly higher in patients who sustained large volume injuries in the pelvis or abdomen, and in patients who sustained injuries in at least three anatomic regions. CONCLUSIONS A novel index that quantifies the magnitude and distribution of mechanical tissue damage volume is a patient-specific index that can be used to identify patients who have sustained injury patterns that predict progression to MOF and SIRS. The preliminary methods will need refinement and prospective validation.