18F-FDOPA PET and MRI characteristics correlate with degree of malignancy and predict survival in treatment-naïve gliomas: a cross-sectional study

INTRODUCTION: To report the potential value of pre-operative (18)F-FDOPA PET and anatomic MRI in diagnosis and prognosis of glioma patients. METHODS: Forty-five patients with a pathological diagnosis of glioma with pre-operative (18)F-FDOPA PET and anatomic MRI were retrospectively examined. The volume of contrast enhancement and T2 hyperintensity on MRI images along with the ratio of maximum (18)F-FDOPA SUV in tumor to normal tissue (T/N SUV(max)) were measured and used to predict tumor grade, molecular status, and overall survival (OS). RESULTS: A significant correlation was observed between WHO grade and: the volume of contrast enhancement (r=0.67), volume of T2 hyperintensity (r=0.42), and (18)F-FDOPA uptake (r=0.60)(P < 0.01 for each correlation). The volume of contrast enhancement and (18)F-FDOPA T/N SUV(max) were significantly higher in glioblastoma (WHO IV) compared with lower grade gliomas (WHO I–III), as well as for high-grade gliomas (WHO III–IV) compared with low-grade gliomas (WHO I–II). Receiver-operator characteristic (ROC) analyses confirmed the volume of contrast enhancement and (18)F-FDOPA T/N SUV(max) could each differentiate patient groups. No significant differences in (18)F-FDOPA uptake were observed by IDH or MGMT status. Multivariable Cox regression suggested age (HR = 1.16, P = 0.0001) and continuous measures of (18)F-FDOPA PET T/N SUV(max) (HR = 4.43, P = 0.016) were significant prognostic factors for OS in WHO I–IV gliomas. CONCLUSIONS: Current findings suggest a potential role for the use of pre-operative (18)F-FDOPA PET in suspected glioma. Increased (18)F-FDOPA uptake may not only predict higher glioma grade, but also worse OS.