18 F-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 SUVmax ) 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 SUVmax 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 SUVmax 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 SUVmax (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.