Exploring the association of glioma tumor residuals from incongruent [¹⁸F]FET PET/MR imaging with tumor proliferation using a multiparametric MRI radiomics nomogram.

Abstract

The study aimed to using multiparametric MRI radiomics to predict glioma tumor residuals (TR_{FET over MR}) derived from incongruent [¹⁸F]fluoroethyl-L-tyrosine ([¹⁸F]FET) PET/MR imaging. One hundred ten patients with gliomas who underwent [¹⁸F]FET PET/MR scanning were retrospectively analyzed. The TR_{FET over MR} was identified by the discrepancy-PET that the extent of resection (EOR) based on MRI subtracted the biological tumor volume on PET images. The MRI parameters and radiomics features were extracted based on EOR and selected by the least absolute shrinkage and selection operator to construct radiomics score (Rad-score). The correlation network analysis of all features was analyzed by Spearman's correlation tests. The methods for evaluating the clinical usefulness consisted of the receiver operating characteristic curve, the calibration curve, and decision curve analysis. The Rad-score of the patients with the TR_{FET over MR} was significantly higher than those with the non TR_{FET over MR} (p < 0.001). The Rad-score was significantly correlated with the discrepancy-PET (r = 0.72, p < 0.001), Ki-67 level (r = 0.76, p < 0.001), and epidermal growth factor receptor (EGFR) of gliomas (r = 0.75, p < 0.001), respectively. Moreover, there was a difference of the correlation network analysis between the TR_{PET over MR} group and non TR_{FET over MR} group. The nomogram combing Rad-score and clinical features had the greatest performance in predicting TR_{FET over MR} (AUC = 0.90/0.87, training/testing). There was a significant difference in prognosis (median OS, 17 m vs. 43 m) between patients with TR_{FET over MR} and non TR_{FET over MR} based on nomogram prediction (p < 0.001). The nomogram based on MRI radiomics would predict gliomas tumor residuals caused by the absence of ¹⁸F-PET PET examination and adjust EOR to improve prognosis.