What is the primary use of diffusion weighted imaging (DWI) sequences?

Diffusion weighted imaging (DWI) sequences are primarily used to detect the presence of stroke, particularly ischemic stroke. In the case of an ischemic stroke, there is a disruption of blood flow, which leads to a subsequent increase in water molecule movement in the affected area of the brain. DWI is sensitive to these changes and can detect strokes within minutes to hours of onset, well before other imaging techniques that rely on detecting structural changes may reveal abnormalities.

This specificity for early stroke detection makes DWI an invaluable tool in emergency medicine and radiology, as rapid identification of strokes can significantly impact patient outcomes. In the context of stroke assessment, DWI sequences reveal hyperintensities in the affected regions, indicating areas of restricted diffusion, which correspond to the stroke-affected tissue.

While DWI is useful for identifying strokes, it does not enhance contrast in anatomical imaging, measure blood flow directly, or visualize bone structures effectively. Instead, it focuses on the movement of water molecules within tissues, providing critical insights in the context of acute neurological changes.