Heterogeneous and volumetric parameters based on static ¹⁸F-FET PET imaging can benefit non-invasive prediction of tumor malignancy and IDH mutation status in adult untreated glioma patients

Objectives: To explore the predictive efficacy of static, heterogeneous and volumetric parameters of static O-(2-[18F]fluoroethyl)-l-tyrosine (¹⁸F-FET) PET imaging in glioma malignancy and isocitrate dehydrogenase (IDH) mutation.

Methods: Fifty eight adult glioma patients (Grade II-IV) with preoperative ¹⁸F-FET PET-CT imaging were enrolled. Seven PET imaging parameters including maximum tumor to background ratio (TBRmax), peak tumor to background ratio (TBRpeak), mean tumor to background ratio (TBRmean), coefficient of variation (COV), heterogeneity index (HI), metabolic tumor volume (MTV) and total lesion standardized uptake (TLU) were chosen for analysis. Pathological and immunohistochemical results were used as reference. ROC analysis and the AUC were used to evaluate the predictive efficacy of these parameters in glioma malignancy and IDH mutation.

Results: All these parameters could significantly predict glioma malignancy between low grade glioma and high grade glioma. TLU (AUC=0.841, P<0.0001), TBRpeak (AUC=0.832, P<0.0001) and HI (AUC=0.826, P<0.0001) had top three predictive performance; while the combination of TBRpeak, HI and TBRmax had the best performance (AUC=0.882, P<0.0001). TLU, HI, MTV and TBRmax could significantly predict IDH mutation. TLU (AUC=0.698, P=0.0074), HI (AUC=0.698, P=0.0159) and MTV (AUC=0.660, P=0.0342) had top three predictive performance; while the combination of TLU, MTV, TBRmax and TBRmean had the best performance (AUC=0.797, P<0.001).

Conclusions: These easily-obtained and highly-repetitive parameters could significantly benefit the non-invasive prediction of glioma malignancy and IDH mutation, which are crucial in treatment planning and prognostic evaluation.