Perfusion-Weighted MRI as a Predictor of Clinical Outcomes following Medullary Infarctions

Abstract

Background: Perfusion-weighted imaging (PWI) is rarely used to evaluate cases of posterior circulation infarctions. We evaluated clinical outcomes, diffusion-weighted imaging (DWI) patterns and angiographic findings in patients experiencing medullary infarctions according to PWI results. Methods: Data from consecutive patients with acute ischemic lesions primarily involving the medulla were analyzed. All patients underwent MRI including DWI, PWI and MR angiography. The patients were grouped according to the presence or absence of a perfusion delay in the medulla and/or inferior cerebellum. Results: Among 35 patients, all but 1 had a PWI of interpretable quality. Of these 34 patients, 18 had a normal perfusion status, while 16 had perfusion defects in the medulla and/or inferior cerebellum. The abnormal PWI group had poor clinical outcomes at 7 days and 1 month after the onset of symptoms. There was no difference in DWI patterns between these 2 groups. The angiographic findings demonstrated that a stenosis of ≧50% or an occlusion of the ipsilesional vertebral artery was frequently observed in the abnormal PWI group (p = 0.001). Multivariate analysis revealed that abnormal PWI and DWI patterns were independently associated with poor early and late outcomes following medullary infarctions. Conclusions: PWI may be a feasible modality for assessing the perfusion status of the posterior circulation and predicting clinical outcomes following medullary infarctions.