Differentiation Methylated From Unmethylated MGMT Gliomas Based On Post-Contrast T1-Weighted Imaging Radiomics

Objective:To explore the value of radiomics parameters of post-contrast T1-weight imaging in the the differential diagnosis of methylated and unmethylated MGMT(O6-methylguanine-DNA methyltransferase)glioma.Methods and Materials:Thirty five patients with glioma confirmed by pathology were retrospectivly analyzed in the First Affiliated Hospital of Anhui Medical University from 2016 to 2018 and was divided into the MGMT methylation group(17 cases)and the MGMT unmethylation group(18 cases)based on genetic test results.All the patients received magnetic resonance imaging and contrast-enhanced scanning before surgery,and AK software was used to calculate the following five characteristics: the histogram parameters,formfactor parameters,texture parameters,the grey level co-occurrence matrix(GLCM)and the grey level run-length matrix(RLM).The step sizes selected for GLCM and RLM were 1,4,and 7.The region of interest(ROI)of each layer of glioma was outlined manually on post-contrast T1 WI.The one-sample K-S test was used to exam whether the calculated parameters were distributed in normal or not.Those data in normal distribution were compared using the independent-sample T test.Otherwise,the M-U test was used.Then the ROC test was used to evaluate the efficacy of each parameter in the diagnosis of methylated and unmethylated MGMT gliomas.Results:MGMT methylated glioma lesions were located more in the right hemisphere than MGMT non-methylated gliomas(P=0.041).And the WHO grading for non-methylated MGMT gliomas was higher than methylated MGMT gliomas(P=0.038).A total of 27 imaging morphological parameters were significantly different between the two groups of gliomas.Variance of histogram characteristic parameters in the MGMT methylated glioma group was significantly lower than that in the MGMT non-methylated glioma(F = 24.957,P = 0.018).Four Cluster Shade and 12 Cluster Prominence parameters of Texture Parameters in the MGMT methylated glioma group were significantly lower than that in the MGMT non-methylated glioma(F=1.291~10.099,P=0.013~0.048).Five correlation parameters of GLCM characteristic parameters in the MGMT methylated glioma group were significantly higher than that in the MGMT non-methylated glioma(F=3.627~5.243,P=0.037~0.045),and one Inertia characteristic parameter in the MGMT methylated glioma group was significantly smaller than that in the MGMT non-methylated glioma(F=5.580,P=0.025).One high Grey Level Run Emphasis parameter(F=3.197,P=0.037)and 1 Short Run High Grey Level Emphasis parameter(F=6.019,P=0.023)of the RLM characteristic parameters were significantly smaller in the MGMT methylated glioma group than that in the MGMT non-methylated glioma.ROC analysis showed that the area under the curve(AUC)of all Direction_offset 4,angle 0_offset 4,all Direction_offset 7_SD in the Cluster Sha de of texture parameters was 0.699,0.706 and 0.696,respectively,and the sensitivity was 88.2%,88.2%,82.4%,the specificity was 55.6%,50.0% and 61.1%,respectively.In the Cluster Prominence of texture parameters,the AUC of all Direction_offset 1,angle 0_offset 1,angle 45_offset 1,angle 90_offset 1,angle 135_offset 1,all Direction_offset 4_SD,angle 45_offset 4 and angle 0_offset 7 in identifying MGMT methylated glioma patients was ranged from 0.670 to 0.725,the sensitivity was ranged from 64.7% to 100%,and specificity range was from 38.9% to 66.7%.The correlation parameters of GLCM,such as AllDirection_offset 1,Angle 0_offset 1 and Angle 135_offset 1,the AUC was 0.706,0.699 and 0.706,respectively,the sensitivity was 100%,100%,88.2%,respectively,and the specificity was 33.3%,33.3% and 50.0%,respectively.For the Inertia,the AUC of AllDirection_offset4_SD was 0.699,the sensitivity was 88.2%,and the specificity was 44.4% in the distinction of MGMT methylated glioma patients.Conclusion:The quantitative parameters based on post-contrast T1-weight imaging radiomics are valuable in the differential diagnosis of methylated and unmethylated MGMT gliomas,which is a non-invasive,method to provides reliable information for patients with methylated MGMT gliomas to receive temozolomide treatment.