Metabolic delineation of IDH1 wild-type Glioblastoma surgical anatomy: how to plan the tumor extent of resection

Purpose: Magnetic resonance imaging (MRI) is the current standard for preoperative planning of glioblastoma (GBM) surgery. However, recent data on the use of 11 C-methionine positron emission tomography ( 11 [C]-MET PET) suggest its role in providing additional information beyond MRI. The purpose of this study is to establish if there is a correlation between anatomical and metabolic data. Methods: : We retrieved all GBM cases treated at our institution from 2014 to January 2021. Preoperative MRI (Enhancing Nodule -EN-, FLAIR and Total Tumor Volume -TTV-) and PET volumes were evaluated to analyze potential correlations between anatomical and metabolic data. These findings were then correlated with pathological results obtained from the different radiological tumor regions. Results: : 150 patients underwent surgery for GBM and 49 of these were also studied preoperatively with 11 [C]-MET PET; PET volume was evaluated in 47 patients. In 33 patients (70.21%) preoperative 11 [C]-MET PET volume > preoperative EN volume and in 11 (23.4%) preoperative 11 [C]-MET PET volume > preoperative TTV. We found a significant correlation between preoperative TTVs and PET volumes (p = 0.016) as well as between preoperative EN volumes and PET volumes (p = <0.001). Histologically, samples from ENs exhibited the conventional GBM morphology while samples from the FLAIR regions showed white matter tissue, with focal to diffuse tumor cells infiltration and areas of reactive astrogliosis. Conclusion: In our series PET volumes correlated with EN and TTV on preoperative MRI, indicating that PET should be considered in the presurgical planning to achieve a supratotal resection.