Preoperative Proton MR Spectroscopic Imaging of Brain Tumors: Correlation with Histopathologic Analysis of Resection Specimens

A, Axial image from a contrast-enhanced SPGR 3D volume dataset (34/3/1) of a patient with an oligoastrocytoma. The locations for which spectra are reconstructed are shown by the grid.

B, Spectral array (16 × 8 × 8 [phase encodes], 1000/144/1) corresponding to the grid shown in the image of A. Note the high NAA levels and moderate choline and creatine levels in the spectra corresponding to the normal MR regions (right side of spectral array). Note the very high choline and low NAA in portions of the contrast enhancement and surrounding tissue (dashed lines) and the lower metabolites in adjacent tissue (double lines).

Contrast-enhanced SPGR (34/3/1) MR and MRS (16 × 8 × 8, 1000/144/1) data from a patient with oligoastrocytoma.

A, MR location and the spectrum for a biopsy that yielded 75% oligoastrocytoma. Note the elevated choline (1.8 times normal) and absent NAA levels.

B, MR location and the spectrum for a biopsy that correlated with the pathologic finding of necrosis, astrogliosis, and white matter. Note the minimal choline, creatine and NAA resonances in this spectrum. Although the image intensity is similar to the region in A, significant spectral differences were observed with elevated choline/normal choline levels correlated with the presence of tumor.

Multiple MR spectra (16 × 8 × 8, 1000/144/1) and corresponding images (contrast-enhanced SPGR [34/3/1]) centered on biopsy locations for a patient with a newly diagnosed GBM. Higher normalized choline levels were observed in the location of the biopsy with 90% tumor compared with others of lower percentages. (WM = white matter)