Discriminating MGMT promoter methylation status in patients with glioblastoma employing amide proton transfer-weighted MRI metrics

OBJECTIVES: To explore the feasibility of using amide proton transfer-weighted (APTw) MRI metrics as surrogate biomarkers to identify the O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status in glioblastoma (GBM). METHODS: Eighteen newly diagnosed GBM patients, who were previously scanned at 3T and had a confirmed MGMT methylation status, were retrospectively analyzed. For each case, a histogram analysis in the tumor mass was performed to evaluate several quantitative APTw MRI metrics. The Mann-Whitney test was used to evaluate the difference in APTw parameters between MGMT methylated and unmethylated GBMs, and the receiver-operator-characteristic analysis was further used to assess the diagnostic performance. RESULTS: Ten GBMs were found to harbor a methylated MGMT promoter, and eight GBMs were unmethylated. The Mean, Variance, 50(th) percentile, 90(th) percentile, and Width(10–90) APTw values were significantly higher in the MGMT unmethylated GBMs than in the MGMT methylated GBMs, with the areas under the receiver-operator-characteristic curves of 0.825, 0.837, 0.850, 0856, and 0.763, respectively, for the discrimination of MGMT promoter methylation status. CONCLUSIONS: APTw signal metrics have the potential to serve as valuable imaging biomarkers for identifying MGMT methylation status in the GBM population.