Serial MR spectroscopy in relapsing reversible posterior leukoencephalopathy syndrome.

Background: Reversible posterior leukoencephalopathy syndrome (RPLS) in atypical locations is difficult to diagnose. Magnetic resonance spectroscopy (MRS) can help, but results to date are discrepant. We aimed to describe MRS findings in each phase of RPLS and evaluate their diagnostic potential.

Methods: We performed MRS, diffusion-weighted imaging and conventional MR during 2 episodes in a patient with hypertensive encephalopathy.

Results: There were multifocal edematous lesions in both frontal lobes, the left temporo-occipital region and both cerebellar hemispheres in the first episode, and in both cerebellar hemispheres and the left pons in the second. Apparent diffusion coefficient values were high. Choline was normal in the acute phase and elevated in the subacute period. N-acetylaspartate was low throughout, even after clinical recovery and disappearance of the lesion on conventional MR. No lactate peak was detected.

Conclusions: MRS helps differentiate RPLS from several encephalopathies and a N-acetylaspartate decrease does not predict a poor outcome.