LAUSR

BACKGROUND IDH mutation status is an important prognostic marker for glial tumors, which is detected immunohistochemically after surgery. Since this method is invasive, easy and noninvasive magnetic resonance imaging (MRI) methods have recently been used in predicting the IDH mutation status. However, there is currently no standard MRI technique to predict IDH mutation. We analyzed the value of conventional MRI to predict IDH mutation and its effect on survival among grade II-III astrocytoma and oligodendroglioma patients. MATERIAL AND METHODS We included WHO grade II-III astrocytoma and oligodendroglioma patients who underwent surgery at Bahcesehir University Goztepe Medical Park Hospital. All patients were analyzed according to their immunohistochemical IDH mutation status. Preoperative conventional MRI studies with respect to their location, diffusion restriction, contrast enhancement, calcification and hemorrhage on susceptibility-weighted image (SWI) or T2*- weighted imaging (T2*WI), and T2 -FLAIR mismatch properties were retrospectively assessed by a neuroradiologist. The relation between MRI characteristics and IDH mutation was analyzed using a chi-square test. The sensitivity and specificity of radiological IDH mutation were determined by ROC analysis. The impact of IDH mutation on survival was also analyzed by Kaplan-Meier tests. RESULTS IDH mutation was found to be positive in 82.5% of tumors histopathologically and 54.4% radiologically. The sensitivity and specificity were 63.8% and 90%, respectively (Area under the curve/AUC = 0.369, p = 0.08). IDH wild gliomas were predominantly diffusion-restricted tumors. IDH mutant tumors were less likely to have contrast enhancement and had lower grades compared to the IDH wild tumors. The median survival time could not be reached and the overall survival was not related to any tumor characteristics or IDH mutation. CONCLUSIONS Conventional MRI predicts IDH-mutation status in Grade II-III astrocytoma and oligodendroglioma. Contrast-enhancement and restricted diffusion were strongly associated with grade III astrocytoma and oligodendroglioma, IDH-wild type. Location, T2-FLAIR mismatch, and SWI did not contribute to making a decision on the IDH mutation status. There was no significant difference between the survival times of patients and their IDH status.