查看文章

Diffusion-weighted imaging (DWI) is a magnetic resonance imaging (MRI) sequence that provides image contrast dependent on the molecular motion of water. Acute ischemia in the central nervous system (CNS) results in disruption of normal cellular metabolism with depletion of ATP causing failure of Na þ/K þ ATPase ionic pumps with loss of ionic gradients across cellular membranes. This causes cytotoxic edema with a net shift of water from the extracellular to the intracellular space and changes in the relative volume of these compartments, as well as alterations in their microenvironments. These rapid biophysical changes result in locally restricted diffusion of water molecules that is readily detected by DWI within minutes of acute onset of ischemia. 1 DWI is highly sensitive (81%–100%) and specific (86%–100%) for detecting acute