Preliminary clinical-radiological assessment of a MR tissue signature model in human stroke

We evaluated the ability of an MR signature model (SM) of cerebral ischemic injury to stage the evolution of cellular damage in human stroke. In 19 patients with ischemic stroke of presumed embolic or non-embolic cause we carried out diffusion-weighted and T₂-weighted MR imaging within 48 h of onset, and obtained apparent diffusion coefficient of water (ADC(w)), and T₂ weighted images. We used the signatures obtained from these ADC(w)/T₂ maps to formulate two patterns of damage signifying accelerated or non-accelerated progression of cellular death after stroke onset. Those patients with the accelerated pattern corresponded to those with the neuroradiological (NRC) and clinical diagnosis (TOAST.1 and TOAST.2) of presumed embolic stroke, with clinical diagnosis performed blinded both to NRC and to SM. Agreement between the SM and NRC was substantial (K=0.62), moderate (0.60<K<0.40) between the SM or NRC and TOAST.2, and fair (0.40<K<0.20) among the SM or NRC and TOAST.1. We believe these results constitute a preliminary validation of the MR tissue signature modeling in clinical stroke assessment.