[Temporal changes of diffusion-weighted MR images in a patient with transient global amnesia]

The pathogenesis of transient global amnesia (TGA) remains uncertain, although it is featured by characteristic clinical symptoms. We present a patient with TGA, in which diffusion-weighted MR image showed a punctuate hyperintense lesion in the left CA1 subfield of the hippocampus adjoining the lateral ventricle 24 hours after the onset. This lesion was observed with FLAIR image after 9 days from the onset, and therefore was considered to be a delayed ischemic lesion. A SPECT and PET studies 7 days after the onset showed a decrease of the CBF, CMRO2 and CMRglu, and was compatible with a delayed ischemic lesion. However, there were no cardiovascular risk factors nor abnormalities of vascular supply, and therefore the reason for microcirculatory disturbances remained unclear.