The major clinical use of diffusion-weighted imaging to date has been in evaluation of cerebral infarction, at which it excels. However, diffusion-weighted imaging has also shown promise for other applications, ranging from quantitative analysis of biologic changes that are not apparent from simple visual inspection of images (but are detectable after using regions of interest on apparent diffusion coefficient maps) to better characterization of other intracranial abnormalities (e.g., abscess and tumor). Both the clinical and research applications of diffusion-weighted imaging can be expected to increase, providing fresh insights into physiologic characteristics of both normal and abnormal tissue.