NIMG-34. QUANTITATIVE MR PARAMETERS FOR THE PREDICTION OF EGFR AMPLIFICATION AND THE TERT PROMOTER MUTATION STATUS OF IDH-WILDTYPE LOWER-GRADE GLIOMAS

Abstract

Abstract OBJECTIVES To assess the predictive role of quantitative MRI parameters from DTI, dynamic susceptibility contrast (DSC), and dynamic contrast-enhanced (DCE) imaging in determining the epidermal growth factor receptor (EGFR) amplification and telomerase reverse transcriptase promoter (TERTp) mutation status of isocitrate dehydrogenase-wildtype (IDHwt) lower-grade gliomas (LGGs). METHODS A total of 49 patients with IDHwt LGGs with either known EGFR amplification (39 EGFR non-amplified, 10 EGFR-amplified) or TERTp mutation (19 TERTp wildtype, 21 TERTp mutant) statuses underwent preoperative MRI. The mean apparent diffusion coefficient (ADC), fractional anisotropy (FA), normalized cerebral blood volume (nCBV), normalized cerebral blood flow (nCBF), volume transfer constant (Ktrans), rate transfer coefficient (Kep), extravascular extracellular volume fraction (Ve), and plasma volume fraction (Vp) values were assessed. Univariate and multivariate logistic regression models were constructed to predict EGFR amplification and TERTp status. RESULTS EGFR-amplified tumors showed lower mean ADC values than EGFR non-amplified tumors (p = 0.019). Mean ADC was an independent predictor of EGFR amplification, with an AUC of 0.75. TERTp mutant tumors showed higher mean nCBV (p = 0.020), higher mean nCBF (p = 0.017), and higher mean Vp (p = 0.002) than TERTp wildtype tumors. With multivariate logistic regression, mean Vp was the only independent predictor of TERTp mutation status, with an AUC of 0.85. CONCLUSION Lower ADC values may be a useful marker for the prediction of EGFR amplification, whereas higher Vp values may be a useful marker for the prediction of the TERTp mutation status of IDHwt LGGs.