Predictive Value Of Amide Proton Transfer Imaging For IDH And MGMT Molecular Typing Of Gliomas

Objective:To investigate the application value of amide proton transfer(APT)imaging in predicting the status of isocitrate dehydrogenase(IDH)and O6-Methylguanine-DNA methyltransferase(MGMT)in gliomas.Methods:A retrospective analysis was conducted on 33 glioma patients who received routine MRI and APT scanning 2 weeks before surgery in First Hospital of Shanxi Medical University from November 2020 to December 2022,and were divided into IDH mutant group and wild group,MGMT methylated group and non-methylated group according to pathological results.Conventional MRI images were used to analyze whether the tumor boundaries were clear or not,whether the shape was regular,the number of cerebral lobes involved,the degree of enhancement,the degree of peritumoral edema,and the internal necrosis and bleeding of the tumors.The original APT image was processed on GE Advanced Workstation 4.4 to obtain the parameter map at APT 3.5ppm.Combined with conventional MRI,ROI was mapped on the tumor parenchyma and the contralateral normal white matter area on T1 WI enhanced imaging,which was copied to the APT 3.5ppm parameter map.The APT signal intensity(APTw value)in the tumor parenchyma area and the APT signal intensity(n APTw value)in the contralateral normal white matter area were obtained.Finally,the ratio of APTw value to n APTw value,namely,the r APTw value,was obtained.Two independent sample t test and Chi-square test were used to compare the clinical data and conventional imaging features of different groups.Two independent sample T-test was used to analyze the differences in APT signal intensity between the IDH mutant group and the wild group,as well as between the MGMT methylated group and the nonmethylated group.Receiver operating characteristic(ROC)curve was drawn.The area under the curve(AUC),sensitivity and specificity were used to determine the diagnostic efficiency of APT signal intensity in predicting the status of IDH and MGMT.Calculate the Yoden index and the optimal threshold.Results:Thirty-three glioma patients were eventually included in this study.There were 4 WHO grade 2 gliomas,12 WHO grade 3 gliomas and 17 WHO grade 4 gliomas.There were 19 patients with IDH wild type glioma,14 patients with IDH mutant glioma,8 patients with MGMT methylated glioma,and 25 patients with MGMT non-methylated glioma.In terms of conventional imaging features,IDH wild-type gliomas showed more involvement of multiple lobes and significant enhancement,while IDH mutant glioma showed more involvement of a single lobe and mild to moderate enhancement,with statistical significance(P <0.05).Other imaging features did not show significant differences between the IDH mutation and wild group and all conventional imaging features did not show significant differences between the MGMT methylated and non-methylated group(P >0.05).Other imaging features showed no significant difference between IDH mutant and wild group and MGMT methylated and non-methylated group.The r APTw value of IDH wild-type group(1.309±0.082)was higher than that of mutant group [(1.214±0.089);t=-3.122,P=0.004],and the area under ROC curve(AUC)was 0.789,the optimal width was 1.255,and the sensitivity and specificity were 0.789 and 0.714 respectively.There was no significant difference in r APTw value between MGMT methylated group and non-methylated group(P=0.755).Conclusion:APT imaging helps to noninvasively predict IDH mutation status of gliomas before surgery,thus helping to evaluate prognosis and guide treatment of glioma patients.