Association of diffusion weighted imaging abnormalities and recurrence in transient global amnesia.

Since the first description of transient global amnesia (TGA) in 1964, its etiology has remained obscure. Reversible diffusion weighted imaging (DWI) hyperintensities in the hippocampus have been found on MRI of some patients with TGA during acute events. The implication of this is not well understood. We identified 47 patients with TGA between November 2004 and November 2009, and enrolled 27 patients with brain MRI within 72 hours of symptom onset for analysis and recorded subsequent relapse or stroke occurrence during follow-up. Nine of the 27 patients had reversible hippocampal punctuate hyperintensities, with complete resolution noted on a second MRI on average 4 months after the initial TGA. Patients with a first relapse (their second TGA attack) had a significantly higher association of DWI hippocampal abnormalities (p=0.03) compared to patients with their first TGA event. None of the 27 patients had a stroke or further relapse during the mean follow-up period of 32.6 months. Thus, patients with recurrent TGA have a significantly higher association of reversible DWI abnormality.