The N-Acetylaspartate to Choline Ratio Differentiates Intracranial Gliomas from Tumefactive Demyelinating Lesions in a Retrospective Cohort Study.

Intracranial gliomas and tumefactive demyelinating lesions (TDLs) often exhibit overlapping features on conventional structural magnetic resonance imaging (MRI), making their differential diagnosis challenging. This retrospective cohort study evaluated the diagnostic performance of quantitative multi-voxel proton magnetic resonance spectroscopy (1H-MRS) for differentiating these lesions. A total of 63 patients with indeterminate intracranial masses, including gliomas, TDLs, and primary central nervous system lymphomas, underwent 1H-MRS. Absolute and relative metabolite ratios were measured within lesional solid cores and contralateral normal-appearing brain tissue. Regions of interest were independently delineated by two blinded neuroradiologists. Although both gliomas and TDLs demonstrated significantly increased choline-to-creatine (Cho/Cr) ratios relative to normal tissue, the Cho/Cr ratio showed limited diagnostic specificity. In contrast, the N-acetylaspartate-to-choline (NAA/Cho) ratio differed significantly between the two groups. The median NAA/Cho ratio was 1.22 (interquartile range [IQR], 0.75-1.60) in TDLs and 0.32 (IQR, 0.20-0.69) in high-grade gliomas. Receiver operating characteristic analysis demonstrated that an NAA/Cho threshold of ≤0.649 yielded a sensitivity of 72.7% (95% confidence interval [CI], 55.8%-84.9%), a specificity of 93.3% (95% CI, 70.2%-98.8%), and an area under the curve (AUC) of 0.848 (95% CI, 0.74-0.96). Inter-reader reproducibility was high, with intraclass correlation coefficients (ICCs) greater than 0.99. These findings suggest that quantitative 1H-MRS, particularly the NAA/Cho ratio, may provide a useful noninvasive metabolic biomarker to support the differentiation of intracranial gliomas from TDLs, although further validation in larger, multicenter cohorts is warranted.