Brain MRI showing large core-penumbra mismatch on diffusion- and perfusion-weighted sequences in a patient with acute ischemic stroke

Diffusion- and perfusion-weighted brain MRI showing a large core-penumbra mismatch in a patient with an acute ischemic stroke. Diffusion-weighted MRI (panel A) indicates the infarction core in red as tissue with apparent diffusion coefficient <620 that measures 17 mL in volume. Perfusion-weighted MRI (panel B) indicates the ischemic penumbra in green as tissue with T_max >6.0 seconds that measures 139 mL in volume. The mismatch volume is 122 mL and the mismatch ratio is 8.2.