We sought to establish the validity of echo-planar diffusion-weighted imaging (DWI) in acute stroke using anisotropic and isotropic imaging. 32 patients with a clinical suspicion of stroke were examined by echo-planar DWI on a 1.5 T magnet. The earliest imaging was performed 90 minutes after onset of symptoms, up to 47 hours In 30 cases art area of hyperintensity was detected in the brain with a corresponding drop in the rADC. The ADC drop varied between 10 and 55% when compared to non-ischemic tissue. In two cases where no lesion was detected symptoms did disappeared and TIAs were diagnosed. Diffusion-weighted imaging of the brain is feasible in patients with acute stroke and appears to be sensitive to the acute cerebral changes encountered in ischemia. I should therefore be possible to use it to select patients for further intervention.