Diffusion- and perfusion-weighted magnetic resonance imaging in human acute ischemic stroke: technical considerations.

Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) are recently developed yet steadily evolving magnetic resonance techniques. DWI and PWI typically interrogate the microscopic diffusion and microcirculatory perfusion, and they can provide early, highly sensitive, and specific delineation of ischemic tissue. These techniques also can play a role in selecting patients who may benefit from thrombolytic therapy. This article reviews physical, technical, and pathophysiological background material that can be helpful in the acquisition and interpretation of DWI and PWI.