Prediction of oligodendroglial histology and LOH 1p/19q using dynamic [~(18)F]FET-PET imaging in intracranial WHO grade II and III gliomas

摘要

Oligodendroglial components (OC) and loss of hetero-zygosity on chromosomes lp and 19q (LOH lp/19q) are associated with better outcome in patients with glioma. We aimed to assess the fitness of [~(18)F]fluoroethyltyrosine positron-emission-tomography (FET-PET) for noninvasively identifying these important prognostic/predictive factors. One hundred forty-four patients with MRI-suspected WHO grade II and III glioma underwent FET-PET scans prior to histologi-cal diagnosis. FET-PET analyses included maximal tumoral uptake (SUV_(max)/BG), biological tumor volume (BTV), mean tumoral uptake (SUV_(mean)/BG), total tumoral uptake (SUV_(total)/BG), and kinetic analysis. Suspicion of OC was based on static and dynamic FET-uptake parameters. PET results were correlated with histology and lp/19q status. OC tumors exhibited significantly higher uptake values, compared with astro-cytomas (AC) (SUV_(max)/BG 3.1 vs 2.3, BTV 15.5 mL vs 7.2 mL, SUV_(total)/BG 38.5 vs 17.4, P<.01 each; SUV_(mean)/BG 2.2 vs 2.1, P<.05). These differences were more pronounced in WHO grade II gliomas. Comparable results were found with respect to lp/19q status. Kinetic analysis misclassified 18 of 34 low-grade OC tumors as high-grade glioma but misclassified only 5 of 45 of the low-grade ACs. FET-based suspicion of OC resulted in concordance rates of both 76% for the prediction of OC and LOH lp/19q. FET-uptake was significantly higher in gliomas with OC, compared with AC, and likewise in lp/19q codeleted, compared with noncodeleted tumors. However, FET-PET analysis did not reliably predict the presence of OC/LOH lp/ 19q in the individual patient, mostly because of an overlap in PET characteristics of OC tumors and high-grade AC. Histological examination is still required for an accurate diagnosis.