Magnetic resonance imaging and computed tomography of cerebral vascular disease.

Magnetic resonance imaging has emerged as the primary modality in detection and characterization of cerebrovascular lesions. New applications of existing spin-echo and gradient-recalled echo techniques are described. Functional imaging techniques ranging from the characterization of macroscopic proton motion (diffusion-weighted MR imaging), rapid imaging of intravascular contrast transit times (perfusion MR imaging), fast-flow mapping (MR angiography), and in vivo metabolic assessment (MR spectroscopy) are discussed. CT scanning remains important as an initial screening examination, in identifying acute hemorrhage, and in demonstrating blood flow.