Trauma and 'Whole' Body Computed Tomography: Role, Protocols, Appropriateness, and Evidence to Support its Use and When

Imaging plays a crucial role in the immediate evaluation of the trauma patient, particularly using multi-detector computed tomography (CT), and especially in moderately to severely injured trauma patients. There are specific areas of relative consensus, while other aspects of whole-body computed tomography (WB-CT) use remain controversial and are subject to opinion/debate based on the current literature. Even a few hours of a delayed diagnosis may result in a detrimental outcome for the patient. One must utilize all the tools available to enhance the interpretation of images. It is also important to recognize imaging pitfalls and artifacts to avoid unnecessary intervention.

Diagnostic accuracy of computed tomography angiography (CTA) for diagnosing blunt cerebrovascular injury in trauma patients: a systematic review and meta-analysis

Objectives

Previous literature showed that the diagnostic accuracy of computed tomographic angiography (CTA) is not equally comparable with that of the rarely used golden standard of digital subtraction angiography (DSA) for detecting blunt cerebrovascular injuries (BCVI) in trauma patients. However, advances in CTA technology may prove CTA to become equally accurate. This study investigated the diagnostic accuracy of CTA in detecting BCVI in comparison with DSA in trauma patients.

Methods

An electronic database search was performed in PubMed, EMBASE, and Cochrane Library. Summary estimates of sensitivity, specificity, positive and negative likelihood, diagnostic odds ratio, and 95% confidence intervals were determined using a bivariate random-effects model.

Results

Of the 3293 studies identified, 9 met the inclusion criteria. Pooled sensitivity was 64% (95% CI, 53–74%) and specificity 95% (95% CI, 87–99%) The estimated positive likelihood ratio was 11.8 (95%, 5.6–24.9), with a negative likelihood ratio of 0.38 (95%, 0.30–0.49) and a diagnostic odds ratio of 31 (95%, 17–56).

Conclusion

CTA has reasonable specificity but low sensitivity when compared to DSA in diagnosing any BCVI. An increase in channels to 64 slices did not yield better sensitivity. There is a risk for underdiagnosis of BCVI when only using DSA to confirm CTA-positive cases, especially in those patients with low-grade injuries.

Key Points

• Low sensitivity and high specificity were seen in identifying BCVI with CTA as compared to DSA.

• Increased CTA detector channels (≤ 64) did not lead to higher sensitivity when detecting BCVI.

• The use of CTA instead of DSA may lead to underdiagnosis and, consequently, undertreatment of BCVI.

Limitations of multidetector computed tomography angiography for the diagnosis of blunt cerebrovascular injury

OBJECTIVE Blunt cerebrovascular injuries (BCVIs) following trauma carry risk for morbidity and mortality. Since patients with BCVI are often asymptomatic at presentation and neurological sequelae often occur within 72 hours, timely diagnosis is essential. Multidetector CT angiography (CTA) has been shown to be a noninvasive, cost-effective, reliable means of screening; however, the false-positive rate of CTA in diagnosing patients with BCVI represents a key drawback. Therefore, the authors assessed the role of DSA in the screening of BCVI when utilizing CTA as the initial screening modality. METHODS The authors performed a retrospective analysis of patients who experienced BCVI between 2013 and 2015 at 2 Level I trauma centers. All patients underwent CTA screening for BCVI according to the updated Denver Screening Criteria. Patients who were diagnosed with BCVI on CTA underwent confirmatory digital subtraction angiography (DSA). Patient demographics, screening indication, BCVI grade on CTA and DSA, and laboratory values were collected. Comparison of false-positive rates stratified by BCVI grade on CTA was performed using the chi-square test. RESULTS A total of 140 patients (64% males, mean age 50 years) with 156 cerebrovascular blunt injuries to the carotid and/or vertebral arteries were identified. After comparison with DSA findings, CTA findings were incorrect in 61.5% of vessels studied, and the overall CTA false-positive rates were 47.4% of vessels studied and 47.9% of patients screened. The positive predictive value (PPV) for CTA was higher among worse BCVI subtypes on initial imaging (PPV 76% and 97%, for BCVI Grades II and IV, respectively) compared with Grade I injuries (PPV 30%, p < 0.001). CONCLUSIONS In the current series, multidetector CTA as a screening test for blunt cerebrovascular injury had a high-false positive rate, especially in patients with Grade I BCVI. Given a false-positive rate of 47.9% with an estimated average of 132 patients per year screening positive for BCVI with CTA, approximately 63 patients per year would potentially be treated unnecessarily with antithrombotic therapy at a busy United States Level I trauma center. The authors' data support the use of DSA after positive findings on CTA in patients with suspected BCVI. DSA as an adjunctive test in patients with positive CTA findings allows for increased diagnostic accuracy in correctly diagnosing BCVI while minimizing risk from unnecessary antithrombotic therapy in polytrauma patients.

Impact of Continuous Evaluation of Technology and Therapy: 30 Years of Research Reduces Stroke and Mortality from Blunt Cerebrovascular Injury

BACKGROUND

Blunt cerebrovascular injury (BCVI) was underdiagnosed until the 1990s when blunt carotid injuries were found to be more common than historically described. Technological advancements and regionalization of trauma care have resulted in increased screening and improved diagnosis of BCVI. The aim of this study was to demonstrate that systematic evaluation of the screening and diagnosis of BCVI, combined with early and aggressive treatment, have led to reductions in BCVI-related stroke and mortality.

STUDY DESIGN

Patients with BCVI from 1985 to 2015 were identified and stratified by age, sex, and Injury Severity Score. BCVI-related stroke and mortality rates were then calculated and compared. Patients were divided into 5 eras based on changes in technology, screening, or treatment algorithms at our institution.

RESULTS

Five hundred and sixty-four patients were diagnosed with BCVI: 508 carotid artery and 267 vertebral artery injuries. Sixty-five percent of patients were male, mean age was 41 years, and mean Injury Severity Score was 27. Incidence of BCVI diagnosis increased from 0.33% to approximately 2% of all blunt trauma (p < 0.001) during the study period. Ninety (14%) patients suffered BCVI-related stroke, with the incidence of stroke significantly decreasing over time from 37% to 5% (p < 0.001). Twenty-eight (5%) patients died as a direct result of BCVI, and BCVI-related mortality also decreased significantly over time from 24% to 0% (p < 0.001).

CONCLUSIONS

Although increased screening has resulted in a higher incidence of injuries over time, BCVI-related stroke and mortality have decreased significantly. Continuous critical evaluation of evolving technology and diagnostic and treatment algorithms has contributed substantially to those improved outcomes. Appraisals of technological advances, preferably through prospective multi-institutional studies, should advance our understanding of these injuries and lead to even lower stroke rates.

Nonmissile Penetrating Head Injuries: Surgical Management and Review of the Literature

BACKGROUND

Nonmissile penetrating head injuries (NPHIs) in the civilian population are rare but potentially fatal. Although numerous cases have been reported in the literature, the surgical management of such injuries is still ambiguous, especially with development of surgical techniques. Here, we report 5 cases of NPHIs managed with different surgical techniques and review the literature on surgical treatment of these injuries to outline the appropriate management for these patients from a neurosurgical perspective.

METHODS

We retrospectively reviewed 5 cases of NPHIs managed surgically in our department. The clinical data were collected, including cause, type of objects, way of penetration, initial clinical evaluation, imaging, surgical intervention, postoperative care, complication, follow-up, and outcome. In addition, a systematic review of the literature was performed in the PubMed database to search for articles on surgical treatment of these injuries.

RESULTS

These 5 cases were caused by twisted steel bar, electric welding rod, and sewing needle, respectively. Preoperative imaging, including computed tomography, magnetic resonance imaging, and digital subtraction angiography, was selectively performed to assist the operative plan. Foreign objects were removed surgically in all cases. Postoperative prophylactic administration of antibiotics and anticonvulsants was used to prevent infectious and epileptic complications. Most of the patients achieved a better outcome except for one.

CONCLUSIONS

NPHIs can be fatal but they can be managed with satisfactory results by proper preoperative imaging evaluation, rapid appropriate surgical management, and accurate postoperative care. Personalized surgical intervention should be undertaken depending on the mechanism and extent of the NPHI.

Partially Thrombosed Internal Maxillary Pseudoaneurysm after Gunshot Wound

A 29-year-old man arrived in our emergency department after being shot on the face. Computed tomography (CT) revealed multiple facial bone fractures along the bullet trajectory. On day 10 of admission, CT angiogram of the neck revealed a partially thrombosed pseudoaneurysm in the parapharyngeal fat pad. The pseudoaneurysm was successfully treated with coil embolization. This report discusses diagnosis and treatment of a partially thrombosed internal maxillary artery pseudoaneurysm. Although digital subtraction angiography is the gold standard for pseudoaneurysm diagnosis, CT angiography may provide complimentary information, as seen in this case.

MDCT imaging of traumatic brain injury

The aim of emergency imaging is to detect treatable lesions before secondary neurological damage occurs. CT plays a primary role in the acute setting of head trauma, allowing accurate detection of lesions requiring immediate neurosurgical treatment. CT is also accurate in detecting secondary injuries and is therefore essential in follow-up. This review discusses the main characteristics of primary and secondary brain injuries.

[Importance of multidetector CT imaging in multiple trauma]

CLINICAL/METHODICAL ISSUE

Diagnostic imaging of complex multiple trauma remains a challenge for any department providing modern emergency radiology (ER) service. An early and comprehensive approach for ER imaging is crucial for a priority-oriented and timely therapy concept with the aim of identifying potentially life-threatening injuries early and initiating appropriate treatment.

STANDARD RADIOLOGICAL METHODS

The basic diagnostic approach still consists of focused ultrasound using focused assessment with sonography for trauma (FAST) and conventional radiography (CR), usually limited to a single supine chest x-ray for triaging patients undergoing immediate operations.

METHODICAL INNOVATIONS

Multidetector computed tomography (MDCT) has become established as early whole body CT (WBCT) as the undisputable diagnostic method. The detection rate of injuries by WBCT is outstanding and it improves the probability of survival by 20-25% compared with all other previous methods. At the same time, the spatial and temporal resolution of MDCT was improved resulting in considerably shortened examination times but WBCT is still associated with a significant radiation exposure, even in the acute single use setting. Using modern scanner and dose reduction technology, including iterative reconstruction, a dose reduction of up to 40% could be achieved. The substantial number of images in WBCT is another challenge; images must be processed priority-oriented, read and transferred to the picture archiving and communications system (PACS). For rapid diagnosis, volume image reading (VIR) offers additional options to keep the diagnostic process on time.

ACHIEVEMENTS/PRACTICAL RECOMMENDATIONS

Modern WBCT after multiple trauma is performed early, comprehensively and personalized so that WBCT improves the probability of survival by 20-25%.

Improving Outcomes in the Patient with Polytrauma: A Review of the Role of Whole-Body Computed Tomography

Whole-body computed tomography (WBCT) is used for the workup of the patient with blunt polytrauma. WBCT is associated with improved patient survival and reduces the emergency department length of stay. However, randomized studies are needed to determine whether early WBCT improves survival, to clarify which patients benefit the most, and to model the costs of this technique compared with traditional workup. Advancements in modern multidetector computed tomography technology and an improved understanding of optimal protocols have enabled one to scan the entire body and achieve adequate image quality for a comprehensive trauma assessment in a short period.

Split bolus technique in polytrauma: a prospective study on scan protocols for trauma analysis

BACKGROUND

For the evaluation of severely injured trauma patients a variety of total body computed tomography (CT) scanning protocols exist. Frequently multiple pass protocols are used. A split bolus contrast protocol can reduce the number of passes through the body, and thereby radiation exposure, in this relatively young and vitally threatened population.

PURPOSE

To evaluate three protocols for single pass total body scanning in 64-slice multidetector CT (MDCT) on optimal image quality.

MATERIAL AND METHODS

Three total body CT protocols were prospectively evaluated in three series of 10 consecutive trauma patients. In Group A unenhanced brain and cervical spine CT was followed by chest-abdomen-pelvis CT in portovenous phase after repositioning of the arms. Group B underwent brain CT followed without arm repositioning by a one-volume contrast CT from skull base to the pubic symphysis. Group C was identical to Group A, but the torso was scanned with a split bolus technique. Three radiologists independently evaluated protocol quality scores (5-point Likert scale), parenchymal and vascular enhancement and artifacts.

RESULTS

Overall image quality was good (4.10) in Group A, more than satisfactory (3.38) in Group B, and nearly excellent (4.75) in Group C (P < 0.001). Interfering artifacts were mostly reported in Group B in the liver and spleen.

CONCLUSION

In single pass total body CT scanning a split bolus technique reached the highest overall image quality compared to conventional total body CT and one-volume contrast CT.

Initial screening test for blunt cerebrovascular injury: Validity assessment of whole-body computed tomography

INTRODUCTION

Our whole-body computed tomography protocol (WBCT), used to image patients with polytrauma, consists of a noncontrast head computed tomography (CT) followed by a multidetector computed tomography (40- or 64- slice) that includes an intravenous, contrast-enhanced scan from the face through the pelvis. WBCT is used to screen for blunt cerebrovascular injury (BCVI) during initial CT imaging of the patient with polytrauma and allows for early initiation of therapy with the goal of avoiding stroke. WBCT has not been directly compared with CT angiography (CTA) of the neck as a screening tool for BCVI. We hypothesize that WBCT is a valid modality to diagnose BCVI compared with neck CTA, thus screening patients with polytrauma for BCVI and limiting the need for subsequent CTA.

METHODS

A retrospective review of the trauma registry was conducted for all patients diagnosed with BCVI from June 2009 to June 2013 at our institution. All injuries, identified and graded on initial WBCT, were compared with neck CTA imaging performed within the first 72 hours. Sensitivity was calculated for WBCT by the use of CTA as the reference standard. Proportions of agreement also were calculated between the grades of injury for both imaging modalities.

RESULTS

A total of 319 injured vessels were identified in 227 patients. On initial WBCT 80 (25%) of the injuries were grade I, 75 (24%) grade II, 45 (14%) grade III, 41 (13%) grade IV, and 58 (18%) were classified as indeterminate: 27 vertebral and 31 carotid lesions. Twenty (6%) of the 319 injuries were not detected on WBCT but identified on subsequent CTA (9 grade I, 7 grade II, 4 grade III); 6 vertebral and 14 carotid. For each vessel type and for all vessels combined, WBCT demonstrated sensitivity rates of over 90% to detect BCVI among the population of patients with at least one vessel injured. There was concordant grading of injuries between WBCT and initial diagnostic CTA in 154 (48% of all injuries). Lower grade injures were more discordant than higher grades (55% vs 13%, respectively; P < .001). Grading was upgraded 8% of the time and downgraded 25%.

CONCLUSION

WBCT holds promise as a rapid screening test for BCVI in the patient with polytrauma to identify injuries in the early stage of the trauma evaluation, thus allowing more rapid initiation of treatment. In addition, in those patients with high risk for BCVI but whose WBCT results are negative for BCVI, neck CTA should be considered to more confidently exclude low-grade injuries.

Arterial injuries after penetrating brain injury in civilians: risk factors on admission head computed tomography

OBJECT

The object of this study was to determine the specific CT findings of the injury profile in penetrating brain injury (PBI) that are risk factors related to intracranial arterial injuries.

METHODS

The authors retrospectively evaluated admission head CTs and accompanying digital subtraction angiography (DSA) studies from patients with penetrating trauma to the head in the period between January 2005 and December 2012. Two authors reviewed the CT images to determine the presence or absence of 30 injury profile variables and quantified selected variables. The CT characteristics in patients with and without arterial injuries were compared using univariate analysis, multivariate analysis, and receiver operating characteristic (ROC) curve analysis to determine the respective risk factors, independent predictors, and optimal threshold values for the continuous variables.

RESULTS

Fifty-five patients were eligible for study inclusion. The risk factors for an intracranial arterial injury on univariate analysis were an entry wound over the frontobasal-temporal regions, a bihemispheric wound trajectory, a wound trajectory in proximity to the circle of Willis (COW), a subarachnoid hemorrhage (SAH), a higher SAH score, an intraventricular hemorrhage (IVH), and a higher IVH score. A trajectory in proximity to the COW was the best predictor of injury (OR 6.8 and p = 0.005 for all penetrating brain injuries [PBIs]; OR 13.3 and p = 0.001 for gunshot wounds [GSWs]). Significant quantitative variables were higher SAH and IVH scores. An SAH score of 3 (area under the ROC curve [AUC] for all PBIs 0.72; AUC for GSWs 0.71) and an IVH score of 3 (AUC for all PBIs 0.65; AUC for GSWs 0.65) could be used as threshold values to suggest an arterial injury.

CONCLUSIONS

The risk factors identified may help radiologists suggest the possibility of arterial injury and prioritize neurointerventional consultation and potential DSA studies.

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.

Blunt cerebrovascular injury screening guidelines: what are we willing to miss?

BACKGROUND

Blunt cerebrovascular injury (BCVI) is reported to occur in approximately 2% of blunt trauma patients, with a stroke rate of up to 20%. Guidelines for BCVI screening are based on clinical and radiographic findings. We hypothesized that liberal screening of the neck vasculature, as part of initial computed tomographic (CT) imaging in blunt trauma patients with significant mechanisms of injury, identifies BCVI that may go undetected.

METHODS

As per protocol, patients at risk for significant injuries undergo a noncontrast head CT scan followed by a multislice CT scan (40-slice or 64-slice) incorporating an intravenous contrast-enhanced pass from the circle of Willis through the pelvis (whole-body CT [WBCT] scan). The trauma registry was retrospectively reviewed, and all patients with BCVI from 2009 to 2012 were analyzed. Patients undergoing WBCT scan were then identified, and records were reviewed for BCVI indicators (skull base fracture, cervical spine injury, displaced facial fracture, mandible fracture, Glasgow Coma Scale score ≤ 8, flexion mechanism, hard signs of neck vascular injury, or focal neurologic deficit).

RESULTS

Of 16,026 patients evaluated during the study period, 256 (1.6%) were diagnosed with BCVI. The population consisted of 185 patients with suspected BCVI after WBCT scan. One hundred twenty-nine patients (70%) had at least one indicator for BCVI screening, while 56 (30%) had no radiographic or clinical risk factors; 48 of the 56 patients underwent confirmatory CT angiography of the neck within 71 hours of initial WBCT scan, with 35 patients having 45 injuries.

CONCLUSION

More liberalized screening for BCVI during initial CT imaging in trauma patients clinically judged to have sufficient mechanism is warranted. Using current BCVI screening guidelines leads to missed BCVI and risk of stroke.

LEVEL OF EVIDENCE

Diagnostic study, level III.

Predicting arterial injuries after penetrating brain trauma based on scoring signs from emergency CT studies

The objective of this study was to determine the accuracy of individual radiologists in detection of vascular injury in patients after penetrating brain injury (PBI) based on head CT findings at admission. We retrospectively evaluated 54 PBI patients who underwent admission head CT and digital subtraction angiography (DSA), used here as a reference standard. Two readers reviewed the CT images to determine the presence or absence of the 29 CT variables of injury profile and quantified selected variables. Four experienced trauma radiologists and one neuroradiologist assigned their own specific scores for each CT variable, a high score indicative of a high probability of artery injury. A sixth set consisted of the average score obtained from the five sets, generated by five experts. Receiver operating characteristic (ROC) curves were constructed for each set to assess the diagnostic performance of an individual radiologist in predicting an underlying vascular injury. The area under ROC curve (AUC) was higher for CT scores obtained from the sixth set (average of five sets of scores) of variable rank score 0.75 (95% CI 0.62-0.88) and for the rest of the data sets, the value ranged from 0.70 (95% CI 0.56-0.84) to 0.74 (95% CI 0.6-0.88). In conclusion, radiologists may be able to recommend DSA with a fair accuracy rate in selected patients, deemed 'high-risk' for developing intracranial vascular injuries after PBI based on admission CT studies. A better approach needs to be developed to reduce the false positive rate to avoid unnecessary emergency DSA.

Incidence and trends in the diagnosis of traumatic extracranial cerebrovascular injury in the nationwide inpatient sample database, 2003-2010

Patients with traumatic extracranial cerebrovascular injury (TCVI) comprise about 1% of all blunt trauma admissions according to numerous single-center studies. However, previous studies have used aggressive screening protocols; these studies may not reflect common practice and the overall incidence of TCVI. The annual incidence of the diagnosis of TCVI from 2003 to 2010 was estimated using the Nationwide Inpatient Sample (NIS). For comparison, a systematic review of previous studies of the incidence of the diagnosis of TCVI was conducted. The estimated total number of admissions with TCVI ranged from 1283 to 2652; these admissions represented 0.46-0.95% of all blunt trauma admissions. There was a significant increase in the incidence of TCVI during the study period. A total of 49 studies of TCVI reported incidences of diagnosis ranging from 0.03% to 4.8%. In conclusion, the annual nationwide incidence of the diagnosis of TCVI is increasing. Although NIS incidences of the diagnosis of TCVI are at the low end of the range of previous reports, the increasing incidence in the NIS data likely reflects increasing use of aggressive screening protocols.

Blunt cerebrovascular injury screening with 64-channel multidetector computed tomography: more slices finally cut it

BACKGROUND

Aggressive screening to diagnose blunt cerebrovascular injury (BCVI) results in early treatment, leading to improved outcomes and reduced stroke rates. While computed tomographic angiography (CTA) has been widely adopted for BCVI screening, evidence of its diagnostic sensitivity is marginal. Previous work from our institution using 32-channel multidetector CTA in 684 patients demonstrated an inadequate sensitivity of 51% (Ann Surg. 2011,253: 444-450). Digital subtraction angiography (DSA) continues to be the reference standard of diagnosis but has significant drawbacks of invasiveness and resource demands. There have been continued advances in CT technology, and this is the first report of an extensive experience with 64-channel multidetector CTA.

METHODS

Patients screened for BCVI using CTA and DSA (reference) at a Level 1 trauma center during the 12-month period ending in May 2012 were identified. Results of CTA and DSA, complications, and strokes were retrospectively reviewed and compared.

RESULTS

A total of 594 patients met criteria for BCVI screening and underwent both CTA and DSA. One hundred twenty-eight patients (22% of those screened) had 163 injured vessels: 99 (61%) carotid artery injuries and 64 (39%) vertebral artery injuries. Sixty-four-channel CTA demonstrated an overall sensitivity per vessel of 68% and specificity of 92%. The 52 false-negative findings on CTA were composed of 34 carotid artery injuries and 18 vertebral artery injuries; 32 (62%) were Grade I injuries. Overall, positive predictive value was 36.2%, and negative predictive value was 97.5%. Six procedure-related complications (1%) occurred with DSA, including two iatrogenic dissections and one stroke.

CONCLUSION

Sixty-four-channel CTA demonstrated a significantly improved sensitivity of 68% versus the 51% previously reported for the 32-channel CTA (p = 0.0075). Sixty-two percent of the false-negative findings occurred with low-grade injuries. Considering complications, cost, and resource demand associated with DSA, this study suggests that 64-channel CTA may replace DSA as the primary screening tool for BCVI.

LEVEL OF EVIDENCE

Diagnostic study, level III.

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.

Transcranial Doppler investigation of hemodynamic alterations associated with blunt cervical vascular injuries in trauma patients

OBJECTIVES

Blunt cervical vascular injuries, often missed with current screening methods, have substantial morbidity and mortality, and there is a need for improved screening. Elucidation of cerebral hemodynamic alterations may facilitate serial bedside monitoring and improved management. Thus, the objective of this study was to define cerebral flow alterations associated with single blunt cervical vascular injuries using transcranial Doppler sonography and subsequent Doppler waveform analyses in a trauma population.

METHODS

In this prospective pilot study, patients with suspected blunt cervical vascular injuries had diagnoses by computed tomographic angiography and were examined using transcranial Doppler sonography to define cerebral hemodynamics. Multiple vessel injuries were excluded for this analysis, as the focus was to identify hemodynamic alterations from isolated injuries. The inverse damping factor characterized altered extracranial flow patterns; middle cerebral artery flow velocities, the pulsatility index, and their asymmetries characterized altered intracranial flow patterns.

RESULTS

Twenty-three trauma patients were evaluated: 4 with single internal carotid artery injuries, 5 with single vertebral artery injuries, and 14 without blunt cervical vascular injuries. All internal carotid artery injuries showed a reduced inverse damping factor in the internal carotid artery and dampened ipsilateral mean flow and peak systolic velocities in the middle cerebral artery. Vertebral artery injuries produced asymmetry of a similar magnitude in the middle cerebral artery mean flow velocity with end-diastolic velocity alterations.

CONCLUSIONS

These data indicate that extracranial and intracranial hemodynamic alterations occur with internal carotid artery and vertebral artery blunt cervical vascular injuries and can be quantified in the acute injury phase by transcranial Doppler indices. Further study is required to elucidate cerebral flow changes resulting from a single blunt cervical vascular injury, which may guide future management to preserve cerebral perfusion after trauma.

Management guidelines for penetrating abdominal trauma

PURPOSE OF REVIEW

Patients with penetrating abdominal trauma are at risk of harboring life-threatening injuries. Many patients are in need of emergent operative intervention. However, there are clearly patients who can be safely managed nonoperatively. This review evaluates the literature to identify management guidelines for patients with penetrating abdominal trauma.

RECENT FINDINGS

Accumulating evidence supports nonoperative management of patients with stab wounds to the thoracoabdominal region, the back, flank, and anterior abdomen. Furthermore, select patients with gunshot wounds can be safely managed nonoperatively.

SUMMARY

Shock, evisceration, and peritonitis warrant immediate laparotomy following penetrating abdominal trauma. Thoracoabdominal stab wounds should be further evaluated with chest X-ray, ultrasonography, and laparoscopy or thoracoscopy. Wounds to the back and flank should be imaged with CT scanning. Anterior abdominal stab wound victims can be followed with serial clinical assessments. The majority of patients with gunshot wounds are best served by laparotomy; however, select patients may be managed expectantly.

Blunt cerebrovascular trauma

PURPOSE OF REVIEW

Blunt cerebrovascular injuries (BCVI) are a rare but potentially devastating injury with stroke rates up to 50%. Over the past decade, the recognition and subsequent management of these injuries has undergone a marked evolution. This review will focus on the rationale for BCVI screening, imaging options, and treatment modalities.

RECENT FINDINGS

There are no prospective randomized controlled trials evaluating the management of BCVI. Available studies support screening a high-risk patient population based upon injury mechanism and constellation of associated injuries using multidetector-row (16-slice or greater) computed tomographic angiography (CTA). Although the ideal regimen of antithrombotic therapy has yet to be determined, treatment with either anticoagulation or antiplatelet agents has been shown to reduce BCVI-related stroke rate.

SUMMARY

Cerebrovascular injuries (CVI) are now diagnosed in approximately 1% of blunt trauma patients. The recognition of a clinically silent period allows for injury screening based upon mechanism of trauma and the patient's injury pattern. Following identification of injuries in asymptomatic patients, prompt initiation of antithrombotic therapy reduces the incidence of stroke.

A novel decision tree approach based on transcranial Doppler sonography to screen for blunt cervical vascular injuries

OBJECTIVES

Early detection and treatment of blunt cervical vascular injuries prevent adverse neurologic sequelae. Current screening criteria can miss up to 22% of these injuries. The study objective was to investigate bedside transcranial Doppler sonography for detecting blunt cervical vascular injuries in trauma patients using a novel decision tree approach.

METHODS

This prospective pilot study was conducted at a level I trauma center. Patients undergoing computed tomographic angiography for suspected blunt cervical vascular injuries were studied with transcranial Doppler sonography. Extracranial and intracranial vasculatures were examined with a portable power M-mode transcranial Doppler unit. The middle cerebral artery mean flow velocity, pulsatility index, and their asymmetries were used to quantify flow patterns and develop an injury decision tree screening protocol. Student t tests validated associations between injuries and transcranial Doppler predictive measures.

RESULTS

We evaluated 27 trauma patients with 13 injuries. Single vertebral artery injuries were most common (38.5%), followed by single internal carotid artery injuries (30%). Compared to patients without injuries, mean flow velocity asymmetry was higher for single internal carotid artery (P = .003) and single vertebral artery (P = .004) injuries. Similarly, pulsatility index asymmetry was higher in single internal carotid artery (P = .015) and single vertebral artery (P = .042) injuries, whereas the lowest pulsatility index was elevated for bilateral vertebral artery injuries (P = .006). The decision tree yielded 92% specificity, 93% sensitivity, and 93% correct classifications.

CONCLUSIONS

In this pilot feasibility study, transcranial Doppler measures were significantly associated with the blunt cervical vascular injury status, suggesting that transcranial Doppler sonography might be a viable bedside screening tool for trauma. Patient-specific hemodynamic information from transcranial Doppler assessment has the potential to alter patient care pathways to improve outcomes.

Diagnostic accuracy of computed tomographic angiography for blunt cerebrovascular injury detection in trauma patients: a systematic review and meta-analysis

OBJECTIVE

To compare the diagnostic accuracy of computed tomographic angiography (CTA) with digital subtraction angiography (DSA) for blunt cerebrovascular injury (BCVI) detection in trauma patients.

BACKGROUND

Controversy exists as to whether the diagnostic performance of CTA compares favorably with the reference-standard, DSA.

METHODS

We searched electronic databases (1950 to May 22, 2012), article bibliographies, conference proceedings (2008-2011), and clinical trial registries for studies comparing the accuracy of CTA with DSA for BCVI detection in trauma patients. Pooled estimates of sensitivity, specificity, and positive and negative likelihood ratios were calculated using bivariate random effects models.

RESULTS

Eight studies that examined 5704 carotid or vertebral arteries in 1426 trauma patients met inclusion criteria. The pooled sensitivity and specificity for BCVI detection with CTA versus DSA was 66% (95% CI, 49%-79%; I = 80.4%) and 97% (95% CI, 91%-99%; I = 94.6%), respectively. Corresponding pooled positive and negative likelihood ratios were 20.0 (95% CI, 6.9-58.4; I = 87.7%) and 0.35 (95% CI, 0.22-0.56; I = 74.9%), respectively. Although pooled sensitivity varied with the number of available CT slices, the training of interpreting radiologists, and in a pattern suggestive of differences in diagnostic threshold for judging CTA positivity, it remained 80% or less among studies that used scanners with 16 or more slices per rotation and where the CTA was read by neuroradiologists.

CONCLUSIONS

Existing evidence suggests that the diagnostic performance of CTA varies considerably across studies, likely due to an implicit variation in diagnostic threshold across trauma centers. Moreover, although CTA appears to lack sensitivity to adequately rule out BCVI, it may be useful to rule in BCVI among trauma patients with a high pretest probability of injury.

Review of multidetector computed tomography angiography as a screening modality in the assessment of blunt vascular neck injuries

Blunt vascular neck injuries (BVNI), previously thought to be rare, have demonstrated increasing incidence rates in recent literature and are associated with significant mortality and morbidity. A radiologist needs to efficiently recognize these injuries on preliminary screening to enable initiation of early management. When initiation of accurate management is started promptly, decreased rates of postinjury complications, for example, stroke, have been demonstrated. This article reviews the incidence, pathophysiology, and rationale for screening for these BVNI injuries. The utility of computed tomography angiography (CTA) as the potential new criterion standard as the screening and follow-up imaging modality for BVNI will be discussed. The application of new multidetector CTA techniques available, such as dual-energy CT and iterative reconstruction, are also reviewed. In addition, the characteristic imaging findings on CTA and the associated Denver Grading scale for BVNI will be reviewed to allow readers to become familiar with the injury patterns and to understand the prognostic and clinical implications, respectively. Examples of the spectrum of injuries, potential injury mimics, and different artifacts on multidetector CTA are shown to help familiarize readers and allow them to successfully and confidently recognize a true BVNI.

Blunt cerebrovascular injury: diagnosis at whole-body MDCT for multi-trauma

Purpose

To analyse the prevalence of blunt cerebrovascular injuries (BCVIs) in multi-trauma patients by means of a post-contrast acquisition of neck vessels included into the whole-body multi-detector computed tomography (MDCT) protocol performed at admission and to correlate it with the presence of risk factors (Memphis approach).

Materials and methods

A retrospective study was undertaken for the period January 2005 to November 2011, involving 976 multi-trauma patients. Post-contrast images of neck vessels in MDCT scan were evaluated by two experienced radiologists; carotid, vertebral and basilar arteries were rated according to the Biffl classification. The presence of clinical and/or CT risk factors for BCVI was assessed.

Results

BCVI were present in 32/976 (3.3 %) multi-trauma patients. Risk factors for BCVI were present in 247/976 (25.3 %) patients. The group of patients presenting risk factors showed a significantly higher prevalence of cerebrovascular injuries (8.1 %) compared with the group of patients without risk factors (1.6 %) (p = 0.009); however, 12/32 (37.5 %) patients presenting BCVI did not show any of the risk factors proposed by the Memphis group.

Conclusion

An investigation for the presence of BCVI should be performed on all multi-trauma patients despite the absence of clinical-radiological risk factors.

Key Points

BCVIs are present in 3.3 % of multi-trauma patients.

BCVIs are significantly associated to the Memphis risk factors.

Of the multi-trauma patients affected by BCVIs, 37.5 % do not show clinical-radiological risk factors.

A screening for BCVI should be performed on all multi-trauma patients.

Current optimal assessment and management of carotid and vertebral spontaneous and traumatic dissection

Dissection of the internal carotid or vertebral artery has been recognized as a cause of stroke in young patients. It is disproportionate in its representation as a cause of stroke in this age group. Intimal tears, intramural hematomas, and dissection aneurysms may be the result of trauma or may occur spontaneously. Spontaneous dissection may be the result of inherent arterial weakness or in association with other predisposing factors. Clinical diagnosis is often difficult, but increased awareness and a range of modern investigations such as computerized tomography or magnetic resonance imaging may aid in diagnosis. Management options include antiplatelet therapy, anticoagulation, thrombolysis, and surgical or endovascular procedures. Prognosis is variable, and dissection may be asymptomatic but may lead to profound neurological deficit and death.

Timing and mechanism of ischemic stroke due to extracranial blunt traumatic cerebrovascular injury

OBJECT

Extracranial cerebrovascular injury is believed to be an important cause of neurological injury in patients who have suffered blunt trauma. The authors sought to determine the timing and mechanisms of ischemic stroke in patients who suffered traumatic cerebrovascular injury (TCVI).

METHODS

This is a prospective study of all patients with TCVI who were admitted to a Level I trauma center during a 28-month period. All patients who suffered blunt trauma and had risk factors for TCVI underwent screening CT angiography (CTA) of the head and neck on admission. All patients with either an ischemic stroke or CTA suggesting TCVI underwent confirmatory digital subtraction angiography (DSA). Patients with DSA-confirmed TCVI were treated with 325 mg aspirin daily; all patients were observed during their hospitalization for the occurrence of new ischemic stroke. In addition, a subset of patients with TCVI underwent transcranial Doppler ultrasonography monitoring for microembolic signals.

RESULTS

A total of 112 patients had CTA findings suggestive of TCVI; 68 cases were confirmed by DSA. Overall, 7 patients had an ischemic stroke in the territory of the affected artery prior to or during admission. Four of the patients had their event prior to diagnosis with CTA and 2 occurred prior to DSA. In 1 patient the ischemic stroke was found to be due to an extracranial atherosclerotic carotid plaque, and this patient was excluded from further analysis. All patients with ischemic stroke had brain CT findings consistent with an embolic mechanism. Two (8.7%) of 23 monitored patients with TCVI had microembolic signals on transcranial Doppler ultrasonography.

CONCLUSIONS

Most ischemic strokes due to TCVI are embolic in nature and occur prior to screening CTA and initiation of treatment with aspirin.

Blunt polytrauma: evaluation with 64-section whole-body CT angiography

Blunt polytrauma remains a leading cause of death and disability worldwide. With the major advances in computed tomography (CT) technology over the past decade, whole-body CT is increasingly recognized as the emerging standard for providing rapid and accurate diagnoses within the narrow therapeutic window afforded to trauma victims with multiple severe injuries. With a single continuous acquisition, whole-body CT angiography is able to demonstrate all potentially injured organs, as well as vascular and bone structures, from the circle of Willis to the symphysis pubis. As its use becomes more widespread, the large volume of information inherent to whole-body CT poses new challenges to radiologists in providing efficient and timely interpretation. An awareness of trauma scoring systems and injury mechanisms is essential to maintain an appropriate level of suspicion in the search for multiple injuries, and the use of multiplanar reformation and three-dimensional postprocessing techniques is important to maximize efficiency in the search. Knowledge of the key injuries that require urgent surgical or percutaneous intervention, including major vascular injuries and active hemorrhage, diaphragmatic rupture, unstable spinal fractures, pancreatic injuries with ductal involvement, and injuries to the mesentery and hollow viscera, is also necessary.

Imaging evaluation of adult spinal injuries: emphasis on multidetector CT in cervical spine trauma

As computed tomography (CT) technology has evolved, multidetector CT has become an integral part of the initial assessment of many injured patients, and the spine is easily included in the total body screening performed in patients with severe blunt polytrauma. Despite all the advantages of multidetector CT, clearing the spine in which injury is suspected continues to be a daily challenge in clinical practice. The purpose of this review is to present the evidence and the controversies surrounding the practice of imaging in patients suspected of having spine injury. The discussion is centered on the increasing reliance on multidetector CT in the work-up of these patients but also considers the important contributions of clinical trials to select patient for appropriate imaging on the basis of risk and probability of injury. Available protocols, injury classification systems, and issues awaiting future research are addressed.

Blunt cerebrovascular injuries: redefining screening criteria in the era of noninvasive diagnosis

BACKGROUND

Screening for blunt cerebrovascular injuries (BCVIs) and early treatment has virtually eliminated injury-related strokes. Screening protocols developed in the 1990s captured ∼80% of ultimately identified BCVI. With the availability of noninvasive diagnosis with computed tomographic angiography, broader indications for screening seem warranted. The purpose of this study was to identify injury patterns of patients with BCVI that are not currently recommended screening criteria.

METHODS

Our prospective BCVI database, initiated in 1997, was queried through December 2010. Indications for screening, injury mechanism, and outcomes were analyzed. Patients younger than 18 years were excluded.

RESULTS

During the 14-year study period, 585 BCVIs were identified in 418 patients (66% men; age, 40 years ± 0.7 years). Eighty-three (20%) patients with BCVI did not have standard screening criteria; 66% were asymptomatic at diagnosis. Injury patterns in these patients included mandible fracture (27 patients), complex skull fractures (21 patients), traumatic brain injury with thoracic trauma (6 patients), scalp degloving (6 patients), and great vessel or cardiac injuries (4 patients). Other injuries (11 patients) and no injuries (8 patients) were identified in the remainder. Of the 307 asymptomatic patients who received antithrombotic treatment, one patient suffered stroke (0.3%) and one patient a transient ischemic attack (0.3%).

CONCLUSIONS

A significant number of patients suffering BCVI are not captured by current screening guidelines. Screening for BCVI should be considered in patients with mandible fractures, complex skull fractures, traumatic brain injury with thoracic injuries, scalp degloving, and thoracic vascular injuries.

LEVEL OF EVIDENCE

II, prognostic study.

Validating the Western Trauma Association algorithm for managing patients with anterior abdominal stab wounds: a Western Trauma Association multicenter trial

The optimal management of stable patients with anterior abdominal stab wounds (AASWs) remains a matter of debate. A recent Western Trauma Association (WTA) multicenter trial found that exclusion of peritoneal penetration by local wound exploration (LWE) allowed immediate discharge (D/C) of 41% of patients with AASWs. Performance of computed tomography (CT) scanning or diagnostic peritoneal lavage (DPL) did not improve the D/C rate; however, these tests led to nontherapeutic (NONTHER) laparotomy (LAP) in 24% and 31% of cases, respectively. An algorithm was proposed that included LWE, followed by either D/C or admission for serial clinical assessments, without further imaging or invasive testing. The purpose of this study was to evaluate the safety and efficacy of the algorithm in providing timely interventions for significant injuries.

METHODS

A multicenter, institutional review board-approved study enrolled patients with AASWs. Management was guided by the WTA AASW algorithm. Data on the presentation, evaluation, and clinical course were recorded prospectively.

RESULTS

Two hundred twenty-two patients (94% men, age, 34.7 years ± 0.3 years) were enrolled. Sixty-two (28%) had immediate LAP, of which 87% were therapeutic (THER). Three (1%) died and the mean length of stay (LOS) was 6.9 days. One hundred sixty patients were stable and asymptomatic, and 81 of them (51%) were managed entirely per protocol. Twenty (25%) were D/C'ed from the emergency department after (-) LWE, and 11 (14%) were taken to the operating room (OR) for LAP when their clinical condition changed. Two (2%) of the protocol group underwent NONTHER LAP, and no patient experienced morbidity or mortality related to delay in treatment. Seventy-nine (49%) patients had deviations from protocol. There were 47 CT scans, 11 DPLs, and 9 laparoscopic explorations performed. In addition to the laparoscopic procedures, 38 (48%) patients were taken to the OR based on test results rather than a change in the patient's clinical condition; 17 (45%) of these patients had a NONTHER LAP. Eighteen (23%) patients were D/C'ed from the emergency department. The LOS was no different among patients who had immediate or delayed LAP. Mean LOS after NONTHER LAP was 3.6 days ± 0.8 days.

CONCLUSIONS

The WTA proposed algorithm is designed for cost-effectiveness. Serial clinical assessments can be performed without the added expense of CT, DPL, or laparoscopy. Patients requiring LAP generally manifest early in their course, and there does not appear to be any morbidity related to a delay to OR. These data validate this approach and should be confirmed in a larger number of patients to more convincingly evaluate the algorithm's safety and cost-effectiveness compared with other approaches.

Multi-detector row CT angiography of the neck in blunt trauma

Blunt cerebrovascular injury (BCVI) is uncommon but potentially catastrophic; 80% are caused by vehicle collisions. Ischemic events secondary to untreated BCVI are common, with high injury-specific mortality. This has led to implementation of screening programs based on mechanism of injury, clinical presentation, and injury patterns identified on noncontrast computed tomography (CT) imaging. The standard of reference for diagnosis is four-vessel digital subtraction angiography. Given its availably in trauma service institutions, use of multidetector CT angiography has increased. This article presents the evidence and the controversies surrounding its use. Available protocols, injury description, and grading, as well as potential pitfalls are reviewed.

A systematic review and meta-analysis of diagnostic screening criteria for blunt cerebrovascular injuries

BACKGROUND

Despite progress in diagnosing and managing blunt cerebrovascular injury (BCVI), controversy remains regarding the appropriate population to screen. A systematic review of published literature was conducted to summarize the overall incidence of BCVI and the various screening criteria used to detect BCVI. A meta-analysis was performed to evaluate which screening criteria may be associated with BCVI. Goals were to confirm inclusion of certain criteria in current screening protocols and possibly eliminate criteria not associated with BCVI.

STUDY DESIGN

Studies published between January 1995 and April 2011 using digital subtraction angiography or CT angiography as a diagnostic modality and reporting overall BCVI incidence or prevalence of BCVI for specific screening criteria were examined. Screening criteria were analyzed using a random effects model to determine if an association with BCVI was present.

RESULTS

The incidence range of BCVI was between 0.18% and 2.70% among approximately 122,176 blunt trauma admissions. The meta-analysis encompassed 418 BCVI and 22,568 non-BCVI patients. Of the 9 screening criteria analyzed, cervical spine (odds ratio [OR] 5.45; 95% CI 2.24 to 13.27; p < 0.0001) and thoracic (OR 1.98; 95% CI 1.35 to 2.92; p = 0.001) injuries demonstrated a significant association with BCVI.

CONCLUSIONS

Patients with cervical spine and thoracic injuries had significantly greater likelihoods of BCVI compared with patients without these injuries. All patients with either injury should be screened for BCVI. Multivariate logistic regression analysis is needed to elucidate the possible impact of the combined presence of screening criteria, but it was not possible in our study due to limitations in data presentation. Standardized reporting of BCVI data is not established and is recommended to permit future collaboration.