Abstract TP96: Low Cerebral Blood Flow Grade Based on Dynamic Magnetic Resonance Imaging Predicts Neurological Deterioration in Patients Treated Without Thrombectomy Because of Low NIHSS Score Despite the Carotid or Middle Cerebral Artery Occlusion

Abstract

Introduction: Most of patients with mild neurological symptoms despite the carotid or middle cerebral artery occlusion (CO or MCAO) are treated without thrombectomy because of no its evidence.However, among them, some patients’ neurological symptoms deteriorate during hospitalization. Methods: We included in our retrospective study acute ischemic stroke patients 1) who were admitted to our institution between April 2011 and January 2018, 2) who could walk before stroke, 3) who underwent MR angiography(MRA), displaying occlusion of the internal carotid artery(ICA) or the M1 segment of the middle cerebral artery(MCA), 4) who presented low NIHSS scores of 4 or less and didn’t undergo thrombectomy.We evaluated patients’ baseline features, NIHSS scores on arrival and at discharge, and time-intensity curve (TIC)-cerebral blood flow (CBF) grade. TICs were generated on region of interests set at symmetrical positions of the bilateral MCA territories. According to the time to peak (TP) and the peak signal (PS) comparing the affected side(a) with the contralateral side(c), we defined (TPa/TPa) divided by (TPc/TPc) as CBF% and grade 1 as CBF% of less than 0.2, grade 2 as CBF% of 0.2 or more and CBF% less than 0.7 and grade 3 as CBF% of 0.7 or more. We defined patients with NIHSS at discharge higher than NIHSS on admission as Group Worse and defined others as Group Non-Worse. Result: Thirty-six patients met our inclusion criteria and were analyzed. The median age was 76.5 years, and 24 patients were men. Median NIHSS score on arrival and at discharge was 2 and 1. There were no patients with CBF grade 1, 8 patients with CBF grade 2 and 28 with CBF grade 3. There were 7 patients in Group Worse and 29 in Group Non-Worse.In Group Worse and Non-Worse, median age was 64 and 78 (ns), median NIHSS score at admission was 2 and 2 (ns), 4 patients and 4 patients in CBF grade 2 and 3 patients and 25 patients in CBF grade 3 (p<0.05) Conclusion: CBF grade based on dMRi is the significant predictor of neurological deterioration. In cases of CBF grade 2 due to the ICA or MCA occlusion, neurological symptoms probably deteriorate in 50% of patients during hospitalization without thrombectomy.