Prognostic value of perfusion- and diffusion-weighted MR imaging in first 3 days of stroke

The aim of this study was to evaluate the differences in cerebral perfusion seen on mean transit time (MTT) and cerebral blood volume (CBV) maps and t o assess the subsequent prognostic value of the MTT-DWI (diffusion-weighted MRI) and CBV-DWI mismatch in the first three days of stroke on lesion enla rgement and clinical outcome. In 38 patients, imaged 1-46 h after onset of symptoms, lesion volumes on proton-density (PD)-weighted MRI, DWI and PWI ( both MTT and CBV maps) were compared with lesion volumes on follow-up PD-we ighted scans, and to clinical outcome (National Institutes of Health Stroke Scale, Barthel index, and Rankin scale). The MTT-CBV, MTT-DWI and in lesio n volume between initial and follow-up PD-weighted scans. Lesion volume on both DWI and PWI correlated significantly with clinical outcome parameters (p < 0.001) with strongest correlation for lesion volume on CBV. Perfusion- diffusion mismatches were found for both CBV and MTT and correlated signifi cantly with lesion enlargement on PD-weighted imaging with strongest correl ation for the CBV-DWI mismatch. The CBV-DWI mismatch has the highest accura cy in predicting lesion size on follow-up imaging and in predicting clinica l outcome. Lesion volume measurements on CBV maps have a higher specificity than on PD-weighted, MTT or DWI images in predicting clinical follow-up im aging and in predicting clinical outcome.