Diffusion-weighted MRI characterizes the ischemic lesion in transient global amnesia.

We present a patient with transient global amnesia (TGA) whose diffusion-weighted MRI (DWI) showed increased signal in the splenium of the corpus callosum and in the left parahippocampal gyrus. The absence of high signal on the corresponding apparent diffusion coefficient (ADC) images supports the diagnosis of an acute infarction. This finding provides a temporal relation between cerebral ischemia and infarction in the territory of posterior cerebral artery and in certain cases of TGA. An early means of detecting ischemia in TGA by DWI may influence clinical decisions made in patient evaluation and management.