Comparison of perfusion imaging parameters with and without symptom progression in mild stroke patients due to large/medium vessel occlusion

BACKGROUND AND PURPOSE: The association between stroke progression in mild stroke due to large or medium vessel occlusion and perfusion imaging parameters remain uncertain. This study aimed to identify perfusion imaging parameters that predict progressive and/or disabling stroke after hospitalization. MATERIALS AND METHODS: This retrospective study analyzed 527 consecutive patients with acute large or medium vessel occlusion (April 2019-March 2024) using Rapid processing of Perfusion and Diffusion (RAPID) imaging. Patients with National Institutes of Health Stroke Scale (NIHSS) ≤ 5 and cervical/internal carotid artery or middle cerebral artery occlusion were classified into the progressive/disabling stroke (PD) group (worsening NIHSS ≥ 4 or disabling deficit despite best medical treatment without EVT) or the non-PD group. Patient characteristics and RAPID imaging parameters (relative cerebral blood flow 4, >6, >8, and > 10 s; and mismatch volume) were compared. Modified Rankin scale (mRS) 0-2 and 0-1 at 90 days were defined as functional outcomes. Statistical analyses included Student's t-test, Wilcoxon rank-sum test, and Youden index. RESULTS: Among 37 patients (mean age, 70.6 ± 15.1 years; 64.9 % male), Tmax > 6 s (73 mL vs. 17 mL, p = 0.007) and mismatch volume (73 mL vs. 16 mL, p = 0.005) were significantly higher in the PD group (n = 9) than in the non-PD group (n = 28). Receiver operating characteristic analysis identified 63 mL as the optimal cutoff value for Tmax > 6 s (sensitivity: 0.78, specificity: 0.82, area under the curve AUC: 0.80) and mismatch volume (sensitivity: 0.78, specificity: 0.82, AUC: 0.82). The PD group had significantly worse functional outcomes at 90 days than the non-PD group (mRS 0-2: 3/8 37.5 % vs. 23/26 88.5 %, p = 0.009; mRS 0-1: 2/8 25.0 % vs. 19/26 73.1 %, p = 0.03). CONCLUSIONS: The prediction of progressive stroke and/or disabling stroke based on perfusion imaging parameters upon admission would allow triage of patients requiring endovascular treatment.