[Regional cerebral blood flow values measured by Xe-CT during the attack of transient global amnesia: a case report].

A 50-year-old right-handed woman was referred to our hospital for further examination of sudden global amnesia. The patient had no history of epilepsy, head injury or cerebral vascular diseases. There were no neurological deficits except for recent memory disturbance. We examined her cerebral blood flow(CBF) immediately during transient global amnesia(TGA) by stable xenon enhanced CT scans(Xe-CT) and twice thereafter. Xe-CT during the attack showed a significant diminution of regional blood flow from the right posterior temporal lobe to the occipital lobe. Conventional MRI scans also had been performed serially but it could not detect the local ischemic event. The ischemic lesion was clearly divided and larger than those cases reported using PET, SPECT, and diffusion-weighted MRI. TGA happens suddenly, and recovery is immediate. It becomes very difficult to study CBF during TGA attack. However stable Xe-CT is capable of examining CBF easily, so we concluded that CBF examination by Xe-CT in TGA patients would be helpful to reveal the mechanism of TGA.