Background: It is often difficult to accurately differentiate tumefactive demyelinating lesions (TDLs) from gliomas using MRI.
Objective: To investigate the utility of proton magnetic resonance spectroscopy (MRS) in differentiating TDLs from gliomas.
Methods: 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).
Results: 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 (ps < 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).
Conclusion: MRS effectively differentiates TDLs from high-grade gliomas. Therefore, the clinical use of MRS is likely to enhance patient outcomes.
Keywords: Glioma; Methionine-pet; Multiple sclerosis; Proton magnetic resonance spectroscopy; Tumefactive demyelinating lesion.
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