Abstract W P37: Accuracy Of CT Angiography In The Localization Of Carotid Occlusion Sites In Acute Ischemic Stroke

Abstract

Background and Purpose: CT angiography yields rapid detection of a major cerebral vessel occlusion during the evaluation of patients with acute ischemic stroke leading to its widespread use in rapidly triaging for IA trial enrollment. In such trials, patients who have an extracranial carotid occlusion in tandem to the intracranial target lesion are typically excluded. However, ICA terminus occlusions may be misidentified as cervical carotid occlusions on CTA. The goal of this study is to determine the accuracy of CTA in identifying ICA terminus occlusions from tandem carotid occlusions (cervical and intracranial segments). Methods: Retrospective review of a prospectively maintained database containing patients treated at our comprehensive stroke center between 1996 and 2014 in whom catheter angiogram and CT angiogram were available on PACS. A Neuroradiologist, blinded to catheter angiographic results reviewed the CT angiography identifying the presence of intracranial stenoses and concomitant cervical carotid occlusions. Results: Of 196 patients presenting with intracranial carotid occlusions on catheter based angiogram, 101 patients were identified with good quality CT angiography and subsequent catheter angiograms. Mean ages for identified patients was 65 +/- 14, of which 52% women and 48% men. Forty-four percent of patients had an ASPECT score of 9-10. The overall rate of agreement between retrospective CTA and conventional angiography readings was 77%. Of 72 isolated intracranial occlusions on conventional angiography, CT angiography misidentified 23 cervical carotid occlusions. The sensitivity of CTA for detecting isolated carotid terminus occlusion was 68% in this cohort. Specific factors associated with CT and catheter based angiographic discrepancy are reviewed. Conclusions: The study raises systematic considerations for maximizing inclusion of patients with target arterial occlusions who are most likely to benefit from intra-arterial therapy in future clinical trials. Future steps will include determination of specificity, predictive value of CTA for localization of specific carotid occlusion sites. Clinical variables associated with lower CTA accuracy will also be examined.