Perfusion and diffusion magnetic resonance imaging (MRI) have been used to guide therapy in patients with large vessel occlusions. In an analogous fashion, the authors used perfusion and diffusion MRI to demonstrate a perfusion deficit and a matching diffusion lesion in a patient with lacunar infarct. Following thrombolytic therapy, the authors observed a reversal of the perfusion deficit, the diffusion lesion, and clinical recovery. This case suggests that perfusion and diffusion MRI may be informative in patients with lacunar infarction who are candidates for thrombolysis.