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FIG 2. Top, A and B, Segmented preoperative T1-weighted sagittal section for 2 patients, 15 and 5 in the Table, respectively. The red sulci and ventricle outline is the output of the tissue/CSF segmentation process. Patient A had a 41-cm3 grade III tumor, 3.0% of his brain volume, and 37% WBNAA deficit. Patient B had a 93-cm3 grade II tumor, 6.2% of his brain volume, but only half the WBNAA decline (
20%).
Bottom, A' and B', Corresponding whole-head 1H-MR spectroscopy. The hatched regions indicate the peak-areas used to obtain QNAA of Equation (1). Note the overall similarity, indicating cross-sectional reproducibility, and good lipid suppression. Also note that, because localization relies on knowledge that NAA is found only in neuronal cells, it cannot quantify the brain’s contribution to metabolites also present in other tissue types (eg, choline, creatine, and so forth).
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