Hippocampal Hyperintensities on Diffusion-Weighted MRI without Transient Global Amnesia

Dot-like hippocampal hyperintensities on diffusion-weighted magnetic resonance imaging (MRI) have been reported as an interesting imaging finding of transient global amnesia (TGA). We report three patients with such dot-like hippocampal hyperintensities who did not present with anterograde amnesia. Episodes associated with the Valsalva maneuver such as nausea or vomiting might have produced the dot-like hippocampal hyperintensities in these patients. However, depending on the individual susceptibility to hippocampal lesions, clinical symptoms of TGA might not be present even when hippocampal lesions are present.