Stroke is the third leading cause of death. Until recently, no diagnostic technique was available that could reliably depict ischemic tissue within a therapeutically promising time window. Since the beginning of this decade, a fundamental change has taken place: Perfusion- and diffusion-MRI have shown to be capable of depicting the ischemic injury immediately after vessel occlusion. While perfusion MRI is sensitive to abnormalities in cerebral capillary blood flow (micro-circulation), diffusion MRI indicates tissue damage on a cellular level. Combining perfusion- and diffusion-MRI with standard MR technique (T2-weighted sequences, MR angiography) results in an MR protocol that is complementary and gives insight into both structural and functional parameters.