Prediction of methylguanine methyltransferase promoter methylation in glioblastoma using dynamic contrast-enhanced magnetic resonance and diffusion tensor imaging

Abstract

Object The methylation status of the methylguanine methyltransferase (MGMT) promoter has been associated with treatment response in glioblastoma. The authors aimed to assess whether MGMT methylation status can be predicted by dynamic contrast-enhanced (DCE) MRI and diffusion tensor imaging (DTI). Methods This retrospective study included 43 patients with pathologically diagnosed glioblastoma who had undergone preoperative DCE-MRI and DTI and whose MGMT methylation status was available. The imaging features were qualitatively assessed using conventional MR images. Regions of interest analyses for DCE-MRI permeability parameters (transfer constant [Ktrans], rate transfer coefficient [Kep], and volume fraction of extravascular extracellular space [Ve]) and DTI parameters (apparent diffusion coefficient [ADC] and fractional anisotropy [FA]) were performed on the enhancing solid portion of the glioblastoma. Chi-square or Mann-Whitney tests were used to evaluate relationships between MGMT methylation and imaging parameters. The authors performed receiver operating characteristic curve analysis to find the optimal cutoff value for the presence of MGMT methylation. Results MGMT methylation was not significantly associated with any imaging features on conventional MR images. Ktrans values were significantly higher in the MGMT methylated group (median 0.091 vs 0.053 min−1, p = 0.018). However, Kep, Ve, ADC, and FA were not significantly different between the 2 groups. The optimal cutoff value for the presence of MGMT methylation was Ktrans > 0.086 min−1 with an area under the curve of 0.756, a sensitivity of 56.3%, and a specificity of 85.2%. Conclusions Ktrans may serve as a potential imaging biomarker to predict MGMT methylation status preoperatively in glioblastoma; however, further investigation with a larger cohort is necessary.

Association of overall survival in patients with newly diagnosed glioblastoma with contrast-enhanced perfusion MRI: Comparison of intraindividually matched T1- and T2*-based bolus techniques

“…A potential limitation of the present study is the sample size, which may limit the power of the statistical analysis, such that some interactions between DSC and DCE parameters may not have been detected. Another limitation is that due to the retrospective design of this study assessment of the DNA repair enzyme O 6 ‐methylguanine‐DNA methyltransferase (MGMT) promoter status was not available for most of the patients, so that we could not determine to what extent this prognostic parameter correlated to the MR perfusions parameters in this cohort . A further limitation is the retrospective design in itself, and our findings encourage the intraindividual comparison of DSC and DCE in larger prospective studies.…”

Radiomics signature: A potential biomarker for the prediction of MGMT promoter methylation in glioblastoma

“…Some studies also illustrated relationships between imaging features and genomic tumor composition . Several prior studies have described distinctive radiological features of GBM with MGMT promoter methylation using conventional MRI, diffusion weighted imaging (DWI), and dynamic contrast‐enhanced MRI (DCE‐MRI), but there are also some discrepancies …”

Conventional and advanced magnetic resonance imaging in patients with high-grade glioma

“…86 A study of 43 GBM patients using DCE-MRIfound that MGMT methylated tumors had increased permeability (higher K trans ) compared to unmethylated tumors. 87 The same group also reported that the initial area under the time-to-signal intensity curve from DCE imaging stratifies survival in promoter unmethylated MGMT GBM, but not in methylated tumors. 89 Arecent study combined both structural and physiologic MR imaging to derive an accurate marker for MGMT promoter methylation status in 92 patients with GBM.…”

“…85 Conversely, higher average ADC values are associated with MGMT promoter methylation. 86, 87 One study found higher rCBV in unmethylated versus methylated tumors, 88 although another study found no significant association. 86 A study of 43 GBM patients using DCE-MRIfound that MGMT methylated tumors had increased permeability (higher K trans ) compared to unmethylated tumors.…”