Abstract TP93: Rapid and Appropriate Evaluation of Collateral Development by Four-Dimensional CT Angiography Covering Only 4-cm Width With a Focus on the Intracranial Internal Carotid Artery and the Middle Cerebral Artery to Identify Candidates of Thrombectomy

Abstract

Introduction: Four-dimensional computed tomography (CT) angiography (4D-CTA) can visualize time sequential changes of bilateral internal carotid (ICA) and middle cerebral arteries (MCA). Therefore, 4D-CTA could find ICA or MCA occlusion and visualize collateral circulation in case of intracranial artery occlusion. Hypothesis: Four-dimensional CTA covering only 4-cm width with a focus on the intracranial ICA and the MCA can early visualize them because of small volumetric data and evaluate collateral development status to identify candidates of thrombectomy. Methods: We included acute ischemic stroke patients who 1) were admitted from August 2018 to July 2019 due to ICA or MCA occlusion, 2) underwent 4D-CTA covering only 4-cm width on admission and 3) underwent endovascular thrombectomy. We classified collateral status into good, moderate and poor collateral according to opacification of M2 and M3 branches distal to occlusion and evaluated successful recanalization of thrombolysis in cerebral infarction (TICI) grade 2b or 3 and improvement of NIHSS score 7 days after thrombectomy. Results: During the study period, 337 acute ischemic stroke patients were admitted, 92 patients suffered from ICA or MCA occlusion and 23 patients met our inclusive criteria. Median age was 81 years and median ASPECTS was 10. Image reconstruction time of 1,000 images was only 69 seconds and 4D-CTA with only 4-cm width demonstrated MCA occlusion in 14 patients, IC occlusion in 9 patients and collateral status as good in 4 patients, moderate in 13 patients and poor in 6 patients. Median onset-to-recanalization time was 5.2 hours, successful recanalization was achieved in 21 patients (91.3%), median NIHSS score on admission was 20, median 7-day NIHSS score decreased to 6 (p<0.0001) and median decrease of NIHSS score was 13. Two patients without successful recanalization had no early improvement of NIHSS score, whereas 20 of 21 patients with successful recanalization obtained early neurological improvement. Conclusion: Four-dimensional CTA with only 4-cm width rapidly and appropriately evaluated collateral status to identify candidates of thrombectomy for ICA or MCA occlusion and achieved early neurological improvement following successful recanalization.