Importance Which imaging modality is optimal to select patients for endovascular stroke treatment remains unclear.
Objective To evaluate the effectiveness of specific magnetic resonance imaging (MRI) and clinical criteria in the selection of patients with acute ischemic stroke for thrombectomy.
Design, Setting, and Participants In this observational, single-center, prospective cohort study, we studied 72 patients with middle cerebral artery or terminal internal carotid artery occlusion using computed tomographic angiography, followed by core infarct volume determination by diffusion weighted MRI, who underwent thrombectomy after meeting institutional criteria from January 1, 2012, through December 31, 2014. In this period, 31 patients with similar ischemic strokes underwent endovascular treatment without MRI and are categorized as computed tomography only and considered in a secondary analysis.
Interventions Patients were prospectively classified as likely to benefit (LTB) or uncertain to benefit (UTB) using diffusion-weighted imaging lesion volume and clinical criteria (age, National Institutes of Health Stroke Scale score, time from onset, baseline modified Rankin Scale [mRS] score, life expectancy).
Main Outcomes and Measures The 90-day mRS score, with favorable defined as a 90-day mRS score of 2 or less.
Results Forty patients were prospectively classified as LTB and 32 as UTB. Reperfusion (71 of 103 patients) and prospective categorization as LTB (40 of 103 patients) were associated with favorable outcomes (P < .001 and P < .005, respectively). Successful reperfusion positively affected the distribution of mRS scores of the LTB cohort (P < .001). Reperfusion was achieved in 27 LTB patients (67.5%) and 24 UTB patients (75.0%) (P = .86). Favorable outcomes were obtained in 21 (52.5%) and 8 (25.0%) of LTB and UTB patients who were treated, respectively (P = .02). Favorable outcomes were observed in 20 of the 27 LTB patients (74.1%) who had successful reperfusion compared with 8 of the 24 UTB patients (33.3%) who had successful reperfusion (P = .004). The ratio of treated to screened patients was 1:3.
Conclusions and Relevance Prospective classification as LTB by MRI and clinical criteria is associated with likelihood of favorable outcome after thrombectomy, particularly if reperfusion is successful. Selection of patients using MRI compares favorably with selection using computed tomographic techniques with the distinction that a higher proportion of screened patients were treated.