Proton magnetic resonance spectroscopy differentiates tumefactive demyelinating lesions from gliomas

It is often difficult to accurately differentiate tumefactive demyelinating lesions (TDLs) from gliomas using MRI.

To investigate the utility of proton magnetic resonance spectroscopy (MRS) in differentiating TDLs from gliomas.

Cohort 1 included 6 patients with TDLs and 5 with gliomas (3 high-grade), as assessed using a 1.5T MR unit. Cohort 2 included 6 patients with TDLs and 17 patients with gliomas (8 high-grade), as assessed using a 3.0T MR unit. Single-voxel proton MRS was performed to compare the following metabolite area ratios: choline (Cho)/creatine (Cr), N-acetylaspartate (NAA)/Cr, and Cho/NAA in both cohorts. Correlations between the target-to-normal-tissue ratio (TNR) obtained using methionine-positron emission tomography (MET-PET) and each MRS metabolite ratio were examined in a subset of cohort 2 (4 patients with TDLs and 11 with gliomas).

Mean Cho/NAA ratio was significantly higher in gliomas than in TDLs or MS in cohort 1 (p < 0.05). Mean Cho/NAA ratio was significantly higher in high-grade gliomas than in TDLs in both cohorts (p_s < 0.05). In the receiver operating characteristic analysis, high-grade glioma rather than TDL was indicated when the Cho/NAA ratio was >1.72 (the area under the curve was 0.958, and the maximum sensitivity and specificity were 100% and 87%, respectively). A significant positive correlation was observed between Cho/NAA ratio and the MET-PET TNR (r²= 0.35, p < 0.05).

MRS effectively differentiates TDLs from high-grade gliomas. Therefore, the clinical use of MRS is likely to enhance patient outcomes.