Combination of Magnetic Resonance Spectroscopy and (11)C-Methionine Positron Emission Tomography for the Accurate Diagnosis of Non-Enhancing Supratentorial Glioma

OBJECTIVE: To evaluate whether the combination of magnetic resonance spectroscopy (MRS) and (11)C-methionine positron emission tomography ((11)C-MET PET) could increase accurate diagnostic sensitivity for non-enhancing supratentorial gliomas. MATERIALS AND METHODS: Between February 2012 and December 2017, 109 patients with non-enhanced supratentorial lesions on contrast-enhanced MRI were enrolled. Each patient underwent MRS and (11)C-MET PET before treatment. A lesion was considered to be a glioma when either the MRS or (11)C-MET PET results reached the diagnostic threshold. The radiological diagnosis was compared with the pathological diagnosis or medical diagnostic criteria. RESULTS: The sensitivity and specificity were 60.0% and 50.0% for MRS and 75.8% and 50.0% for (11)C-MET PET, respectively. Upon combining the two modalities, the sensitivity and specificity of the imaging-based diagnosis prior to surgery reached 89.5% and 42.9%, respectively. Statistically significant differences in the sensitivities were observed between the combined and individual approaches (MRS alone, 89.5% vs. 60.0%, p < 0.001; (11)C-MET PET alone, 89.5% vs. 75.8%, p = 0.001). However, no significant differences in specificity were observed between the combined and individual modalities. CONCLUSION: The combination of MRS and (11)C-MET PET findings significantly increases accurate diagnostic sensitivity for non-enhancing supratentorial gliomas without significantly lowering the specificity. This finding suggests the potential of the combined MRS and (11)C-MET PET approach in clinical applications.