Fig 2. Axial FLAIR, T2-weighted FSE, contrast-enhanced T1-weighted SE MR images and axial CBV map in a 27-year-old woman with meningoencephalitis. There is an abnormal high T2 signal intensity in the left frontal lobe with minimal enhancement on the postgadolinium image. The CBV map shows slightly elevated levels of blood volume in the lesion compared with the normal contralateral side, with a rCBV of 1.35. The original diagnosis on the basis of conventional MR imaging favored a neoplasm over an inflammatory cause. At 3 weeks of follow-up (MR spectroscopy was not performed), an overall improved appearance with a decrease in the size of the frontal subcortical and deep white matter T2 signal intensity abnormality was noted. A, B, The abnormal signal intensity of the lesion extended over 5 FSE sections (5-mm section thickness, no gap; with 2 sections showing the bulk of the lesion). One MRSI section (the bottom section shown in the figure) covered the lesion. Images of the Cho, Cr, NAA, and lactate metabolites and proton MR spectra of the lesion (voxel 2) and control region (voxel 1) are shown. The NAA/Cho ratio of 1.15 was above the cutoff point of 0.61, Cho_norm was 0.8, and rCBV was slightly below the cutoff point of 1.5. On the basis of MRSI and perfusion MR imaging, the presence of a nonneoplastic lesion was favored. Discriminant function analysis classified this lesion as nonneoplastic on the basis of MRSI data alone and MRSI and perfusion MR imaging data.