Magnetic resonance imaging for stroke: Basis principles and clinical use.

Stroke is the third leading cause of death. Until recently, no diagnostic t echnique 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 sho wn to be capable of depicting the ischemic injury immediately after vessel occlusion. While perfusion MRI is sensitive to abnormalities in cerebral ca pillary blood flow (micro-circulation), diffusion MRI indicates tissue dama ge on a cellular level. Combining perfusion- and diffusion-MRI with standar d MR techniques (T-2-weighted sequences, MR angiography) results in an MR p rotocol that is complementary and gives insight into both structural and fu nctional parameters.