MR Mismatch Profiles in Patients with Intracranial Atherosclerotic Stroke: A Comprehensive approach Comparing Stroke Subtypes

Abstract

Most clinical trials have focused on the presence of perfusion- and diffusion-weighted imaging (PWI–DWI) mismatch by more than 20%, and different stroke subtypes were lumped together. We hypothesized that intracranial large artery atherosclerotic stroke (IC-LAA) would show different PWI–DWI and magnetic resonance angiography (MRA)–DWI mismatch profiles, compared with other stroke subtypes. Consecutive patients underwent pretreatment multiparametric magnetic resonance imaging for the acute middle cerebral artery infarcts within 6 h of symptom onset. We assessed the difference in the DWI–PWI mismatch ratio, severity of hypoperfusion, and MRA–DWI mismatch among the stroke subtypes. Of 86 patients, 19 (22.1%) had IC-LAA; 42 (48.8%) cardioembolic stroke, 15 (17.4%) extracranial-LAA, and 10 (11.6%) had cryptogenic embolic stroke. Although the volume of the penumbra was not different among the groups, the mismatch ratio was higher (P=0.003) and the severity of hypoperfusion was lower in the IC-LAA group (P=0.001). The MRA–DWI mismatch was more prevalent in the IC-LAA group than in other groups ( P < 0.001). Collateral grading, assessed in 41 patients, was more likely to be intermediate/excellent in the IC-LAA group ( P < 0.001). Multivariate testing revealed that a larger mismatch ratio and less severe hypoperfusion, and MRA–DWI mismatch were independently associated with IC-LAA. Our data show that patients with IC-LAA had different mismatch profiles, which were related to better collaterals, compared with other subtypes.