FIG 2. Patient 2. T2-weighted MR images, metabolic choline (Cho), creatine (Cr), N-acetylaspartate (NAA), and lipid images, and spectra from selected regions of interest (frontal and posterior white matter, mesial occipital gray matter) are shown.

A, Images obtained at time of episode. Quantitative analysis (Table) indicated that the primary abnormality was increased levels of choline and creatine with mildly lower N-acetylaspartate.

B, Images obtained at 2-month follow-up. A globally reduced ratio of N-acetylaspartate:choline is apparent throughout the brain, which has normalized by the time of follow-up. As in (Figure 1), posterior edematous regions exhibit lower signal intensity on MR spectroscopic images compared with other regions. MR spectroscopic imaging hypointensity in the frontal lobe most noticeable in the creatine image is an artifact due to magnetic field inhomogeneity in this region.