Auteur(s) : Bani Jacob
Composante : MEDECINE
Date de création : 30-06-2021

Description : Médecine nucléaire, Introduction : Gliomas are rare and hetrogenics tumors. Histo-pathologic diagnostic differenciates gliomas from their cellular origin, tumoral grading and biomolecular characteristics due to a different natural history. Radiological diagnosis is mainly represented by brain MRIwith gadolinium injection, allowing to presume the degree of malignancy of gliomas.The interest of PET-CT at 18F-FDOPA and PET-CT at 18F-FDG at the initial assessment and recurrence of gliomas, particularly for diagnosis and prognosis, has been widely studied. Few studies have compared carbohydrate metabolism and amino acid metabolism of gliomas. Objectives : The main purpose of this work is to compare the carbohydrate metabolism and amino acid metabolism of gliomas at baseline and recurrence. Method : One hundred and ninety-four patients performed a PET-CT scan at 18F-FDG and 18F-FDOPA as part of the initial assessment of suspected glial tumours or suspected recurrence. Normalized tumor SUV ratios to the contralateral healthy side and to the homolateral cerebellum in 18F-FDG or to the contralateral healthy side and striatum in 18F-FDOPA and retention index were calculated on the images taken 30 min and 4 hours after injection of 18F-FDG. One hundred and eight patients were eventually included retrospectively in this work, 76 patients at baseline (44 high-grade gliomas and 32 low-grade gliomas) and 32 (17 high-grade gliomas and 15 low-grade gliomas) at recurrence. Results : Significant differences were observed between amino acid metabolism and carbohydrate metabolism of high-grade and low-grade gliomas at an initial assessment. At recurrence, only amino acid metabolism and retention index values make it possible to distinguish between high-grade and low-grade gliomas. ROC curves defining SUV ratio and retention index thresholds have made it possible to find the best thresholds to differentiate gliomas according to their survival. Carbohydrate metabolism on images taken 4 hours after injection of 18F-FDG and the retention index are good indicators of survival, using an nSUV FDG4h threshold of 0.6 and an IR threshold of 0.01. High-grade gliomas and hypometabolic glioblastomas compared to the contralateral side in 18F-FDG have a carbohydrate metabolism decoupled from that of amino acids. Conclusion: This work was able to establish that, as part of the initial assessment of gliomas : 1. there is a correlation between tumor metabolism (glucose and certain amino acids) and the degree of glioma malignancy ; 2. the nSUV FDG4h values, as well as the FDG retention index, are good indicators of patient survival (PFS and OS) ; 3. regarding glioblastomas, there is a subgroup of patients in whom glucose metabolism and the metabolism of certain amino acids are decoupled
Mots-clés libres : Gliomes, Métabolisme énergétique, Tomodensitométrie, Pronostic (médecine), Corrélation de données -- Dissertation universitaire, 616.075
Couverture : FR