Diffusion-weighted MR Imaging: clinical applications in neuroradiology.

Among functional magnetic resonance imaging techniques, diffusion-weighted imaging (DWI) plays an important role in the assessment of a wide variety of brain diseases. DWI provides image contrast that depends on the molecular motion of water and it can be easily added to a standard cranial MR examination, with limited increase in time (imaging time ranges from a few seconds to 2 minutes). DWI is particularly sensitive in the detection of acute ischaemic stroke and in monitoring its evolution (also in the light of new therapeutic strategies for early treatment). Diffusion-weighted MR imaging also provides adjunctive information in the differential diagnosis of other brain diseases including neoplasms, intracranial infections, traumatic brain injury and demyelination some of which may manifest with sudden neurological deficits mimicking acute ischaemic stroke.