Transient global amnesia (TGA) has been a well-described phenomenon for more than 40 years. Clinically, it manifests with a paroxysmal, transient loss of memory function. Immediate recall ability is preserved, as is remote memory; however, patients experience striking loss of memory for recent events and an impaired ability to retain new information. In some cases, the degree of retrograde memory loss is mild.
This method of imaging allows detection of hyperacute ischemic change. Liang et al and Yang et al have also recently used DWI to document tiny lesions in the hippocampus of patients with acute TGA. However, Eustache et al reported a PET study consistent with a spreading depression in the left lateral frontal cortex. This case also featured oligemia in the left occipital cortex. Strupp et al found mainly medial temporal changes on DWI in 7 of 10 patients with TGA. They suggested that cellular edema or spreading depression could be responsible, not just ischemia.