Diagnostic performance of 11C-methionine PET in newly diagnosed and untreated glioma based on the revised WHO 2016 classification.

Abstract

BACKGROUND\nThe relationship between uptake of amino acid tracer with PET and glioma subtypes/gene status is still unclear.\n\n\nOBJECTIVE\nTo assess the relationship between uptake of 11C-methionine using PET and pathology, IDH mutation, 1p/19q codeletion, and TERT promoter status in gliomas.\n\n\nMETHODS\nThe participants were 68 patients with newly diagnosed and untreated glioma who underwent surgical excision and preoperative 11C-methionine PET examination at Osaka City University Hospital between July 2011 and March 2018. Clinical and imaging studies were reviewed retrospectively based on the medical records at our institution.\n\n\nRESULTS\nThe mean L/N ratio of diffuse astrocytomas were significantly lower than those of anaplastic astrocytomas (p=.00155), glioblastoma (p<.001) and oligodendrogliomas (p=.0157). The mean L/N ratio of IDH mutant gliomas was significantly lower than that of IDH wild-type gliomas (median 1.75 vs 2.61; p = .00162). A mean L/N ratio of 2.05 provided the best sensitivity and specificity for distinguishing between IDH mutant and IDH wild-type gliomas, 69.2% and 76.2%, respectively. The mean L/N ratio of TERT promoter mutant gliomas was significantly higher than that of TERT promoter wild-type gliomas (p=.0147). Multiple regression analysis revealed that pathological diagnosis was the only influential factor on L/N ratio.\n\n\nCONCLUSIONS\nDistinguishing glioma subtypes based on the revised 2016 WHO classification of the central nervous system tumors on the basis of 11C-methionine PET alone appears to be difficult. However, 11C-methionine PET might be useful for predicting the IDH mutation status in newly diagnosed and untreated gliomas noninvasively prior to tumor resection.