16-Slice CT angiography (CTA) in patients with suspected blunt carotid and vertebral artery injuries

Abstract

Conclusion: Multidetector computed tomography angiography (CTA) should supplant digital subtraction angiography (DSA) as a screening modality for patients with possible carotid or vertebral artery injuries after blunt trauma. Summary: Detection of carotid injury after blunt trauma is problematic. With the advent of multidetector CTA and the liberal use of CT scanning in patients with blunt trauma, CTA may serve as a viable alternative to angiography for screening for carotid or vertebral artery injuries after blunt trauma. In this study, the authors sought to determine whether CTA performed with a 16-slice multidetector CT scanner can be used as an initial imagining examination in patients with suspected vertebral artery or carotid blunt injury. Predictive values of clinical variables for screening for carotid or vertebral artery injury were also estimated. This was a retrospective study of patients imaged at a Level 1 trauma center for suspected blunt carotid or vertebral artery injury in 2004. Patients were evaluated by CTA if they met criteria suggestive of possible blunt carotid or vertebral artery injury. These criteria included symptoms or signs of carotid or vertebral artery injury and various injury mechanisms or patterns of injury thought to be associated with an increased risk for carotid or vertebral artery injury. Evaluation included a CTA, and then, at the discretion of the clinical service, DSA was performed to confirm a negative CTA. The primary variable evaluated was the proportion of patients with normal CTAs who also had a normal DSA. There were 372 patients imaged with CTA for suspect carotid or vertebral artery injury. Of these, 271 had normal study results, and 82 (30%) also underwent DSA. DSA was equivocal or normal in 75 of these 82 patients, a 92% negative-predictive value of CTA for carotid or vertebral artery injury (95% confidence interval [CI], 83% to 97%). The positive-predictive value for the clinical screening criteria for carotid or vertebral artery injury was 19% (95% CI, 14% to 23%). Of potential variables predicting carotid or vertebral artery injuries, lateral element cervical vertebral fractures and skull-based fractures were most predictive of a carotid or vertebral artery injury. Comment: Catheter-based angiography should not be routinely required to rule out carotid or vertebral artery injury in 2007. Unfortunately, this study has significant limitations that do not permit such a definitive conclusion. These limitations include the fact not all patients with a negative CTA had DSA; therefore, the negative-predictive value of CTA may either be under-estimated or over-estimated by the study. It is also not possible to determine either the sensitivity or specificity of CTA in detecting carotid or vertebral artery injury. There was no systematic follow-up of patients to assess for late stroke, the end point that really matters. Finally, many trauma centers are now equipped with even more advanced CT scanners, making the results of this study perhaps obsolete even before publication.