In the first part of the study, patients with radiological criteria of GBM amenable to surgical resection will be included ; pre-operative multimodal MRI scans will be done and all data acquired (including H1MRS and DTI data) will be integrated in the image-guided surgical device (ie neuronavigation system) to be used intraoperatively. During tumor resection, tissue samples will be individualized, based on their multimodal imaging characteristics and sent to the radiobiology laboratory INSERM for biological analysis.