^{11 11} C-Methionine ^{C-Acetate PET/CT} PET/CT ^for in ^Reactive Glioma ^Astrogliosis Classification ^Outperforms and Survival Prediction

Purpose: ¹¹C-acetate (ACE) PET/CT visualizes reactive astrogliosis in tumor microenvironment. This study compared ¹¹C-ACE and ¹¹C-methionine (MET) PET/CT for glioma classification and predicting patient survival. Patients and Methods: In this prospective study, a total of 142 patients with cerebral gliomas underwent preoperative MRI, ¹¹C-MET PET/CT, and ¹¹C-ACE PET/CT. Tumor-to-contralateral cortex (TNR_MET) and tumor-to-choroid plexus ratios (TNR_ACE) were calculated for ¹¹C-MET and ¹¹C-ACE. The Kruskal-Wallis test and Bonferroni post hoc analysis were used to compare the differences in ¹¹C-TNR_MET and ¹¹C-TNR_ACE. The Cox proportional hazards regression analysis and classification and regression tree models were used to assess progression-free survival (PFS) and overall survival (OS). Results: The median ¹¹C-TNR_MET and ¹¹C-TNR_ACE for oligodendrogliomas (ODs), IDH1-mutant astrocytomas, IDH1-wildtype astrocytomas, and glioblastomas were 2.75, 1.40, 2.30, and 3.70, respectively, and 1.40, 1.20, 1.77, and 2.87, respectively. The median ¹¹C-TNR_MET was significantly different among the groups, except between ODs and IDH1-wildtype astrocytomas, whereas the median ¹¹C-TNR_ACE was significantly different among all groups. The classification and regression tree model identified 4 risk groups (IDH1-mutant with ¹¹C-TNR_ACE ≤ 1.4, IDH1-mutant with ¹¹C-TNR_ACE > 1.4, IDH1-wildtype with ¹¹C-TNR_ACE ≤ 1.8, and IDH1-wildtype with ¹¹C-TNR_ACE > 1.8), with median PFS of 52.7, 44.5, 25.9, and 8.9 months, respectively. Using a ¹¹C-TNR_ACE cutoff of 1.4 for IDH1-mutant gliomas and a ¹¹C-TNR_ACE cutoff of 2.0 for IDH1-wildtype gliomas, all gliomas were divided into 4 groups with median OS of 52.7, 46.8, 27.6, and 12.0 months, respectively. Significant differences in PFS and OS were observed among the 4 groups after correcting for multiple comparisons. Conclusions: ¹¹C-ACE PET/CT is better for glioma classification and survival prediction than ¹¹C-MET PET/CT, highlighting its potential role in cerebral glioma patients.