[Two cases of hippocampal infarction with persistent memory impairment in which diffusion-weighted magnetic resonance imaging was useful].

We present two patients (case 1: a 78-year-old right-handed woman, case 2: a 66-year-old right-handed woman) with suspected transient global amnesia. Both patients showed sudden onset amnesia that appeared to resolve within 24 hours, and they showed no abnormal findings on electroencephalography or single photon emission tomography. However, the results of the Wechsler Memory Scale-Revised (WMS-R) on the ninth (case2) or tenth day (case1) after the onset indicated memory impairment. And diffusion-weighted magnetic resonance imaging (DWI) revealed a unilateral high-intensity area in the hippocampus, leading to the diagnosis of hippocampal infarction in both patients. Case 1 had a left hippocampal lesion and exhibited impairment of predominantly verbal memory, while case 2 had a right hippocampal lesion and demonstrated impairment of predominantly visual memory. When evaluating a patient with suspected transient global amnesia, imaging of the hippocampus and tests on memory function after an appropriate interval from the onset are often helpful in establishing a correct diagnosis.