Introduction: It remains unclear how strongly perfusion findings are related to neurological severity (NS) and MR-DW images (DWI).
Hypothesis: CBF grade based on MR perfusion (MRp) is related to NS or DWI and can identify candidates for endovascular therapy (ET).
Methods: Included in our retrospective analysis were acute ischemic stroke patients 1) who were admitted to our stroke center within 24 hours of the onset between Jan 2004 and May 2015, 2) who presented NIHSS as NS of 0 or more, 3) who underwent MRA, displaying complete occlusion of the affected carotid artery. We evaluated patients’ baseline features, NIHSS, DWI-ASPECTS (ACT) at arrival and CBF grade, which was calculated by using bilateral time-intensity curves (TICs) of MR perfusion. According to the time to peak (TP) and the peak signal (PS) comparing the affected side (a) with the contralateral side (c), we regarded the affected-sided PSa divided by TPa as possible CBFa and the contralateral-sided PSc divided by TPc as possible CBFc. CBF grade 1 was defined as CBFa divided by CBFc (CBF%) 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.
Results: During the study period, 176 patients matched our criteria for analysis. Median NIHSS was 18, and median ACT was 6. There were 30 patients with CBF grade1, 81 with grade2 and 65 with grade3. Median NIHSS in grade1, 2, and 3 patients was 23, 19, and 7 (p<0.0001), respectively, and there was a statistical significant difference between any grade groups (p<0.016). Median ACT in grade1, 2, and 3 was 1, 5, and 8 (p<0.0001), respectively, and there was a statistical significant difference between any grade groups (p<0.016).
Among 32 patients with NIHSS of 7 or less and ACT of 8 or more, there were 28 (87.5%) in grade3. Among 10 patients with NIHSS of 23 or more and ACT of 1 or less, there were 9 (90%) in grade1. Among 40 patients with NIHSS of 8 or more and ACT of 8 or more, there was 22 (55%) in grade2 and 18 (45%) in grade3.
Conclusion: CBF grade defined by MRp had strong relation to NIHSS and ACT. Patients with lower NIHSS score but higher ACT score were probable candidates for ET and many among them belonged to CBF grade2.