Diffusion weighted MRI in the early phase after electroconvulsive therapy.

Although cognitive side effects may occur after electroconvulsive therapy (ECT), no structural brain abnormalities have been detected after ECT with conventional magnetic resonance imaging (MRI). Transient disturbances of memory function are common findings after ECT indicating functional compromise. Diffusion weighted imaging (DWI) has been shown to be sensitive to focal tissue changes associated with compromise of energy metabolism in cerebral ischemia and after prolonged ictal activity. We used conventional MRI and DWI in an exploratory study examining ten patients after treatment with ECT, eight of whom experienced short-lasting memory disturbances. MRI and DWI showed no definite signal abnormalities on qualitative and quantitative analysis. In three patients, equivocal marginal DWI hyperintensity was noted in the hippocampal formation. These findings are in line with previous negative studies using conventional MRI. Higher resolution DWI and serial imaging may be necessary to visualize possible minimal signal changes after ECT.