carbon-11-methionine and Central-Nervous-System-Neoplasms

To perform a meta-analysis evaluating the diagnostic accuracy of . A systematic database search was performed by a librarian in relevant databases with the latest search on 07 November 2016. Hits were assessed for inclusion independently by two authors. Individual patient data on relative MET uptake was extracted on patients examined pre-operatively with MET PET and subsequent neuropathological diagnosis of astrocytoma or oligodendroglioma. Individual patient data were analysed for diagnostic accuracy using a bivariate diagnostic random-effects meta-analysis model with restricted maximum likelihood estimation method. Bivariate meta-regression and subgroup analyses assessed study heterogeneity and validity. This study is registered with PROSPERO, number CRD42016050747.. Out of 1828 hits, 13 studies comprising of 241 individuals were included in the quantitative and qualitative analysis. MET PET had an area under the bivariate summary receiver operating characteristics curve of 0.78 to discriminate between LGG and HGG and a summary sensitivity of 0.80 with 95% confidence interval (CI) (0.66-0.88) and a summary false positive rate of 0.28, 95% CI (0.19-0.38). Heterogeneity was described by; bias in patient inclusion, study quality, and ratio method. Optimal cutoff for relative MET uptake was 2.21.. MET PET had a moderately high diagnostic accuracy for the discrimination between primary LGG and HGG. Advances in knowledge: MET PET can be used as a clinical tool for the non-invasive discrimination between LGG and HGG with a moderately high accuracy at cut-off 2.21.

Topics: Central Nervous System Neoplasms; Glioma; Humans; Likelihood Functions; Methionine; Neoplasm Grading; Positron-Emission Tomography; Radiopharmaceuticals; ROC Curve; Sensitivity and Specificity

Primary central nervous system lymphoma (PCNSL) responds relatively quickly to chemotherapy or radiotherapy. However, determination of a complete response after treatment is often difficult because of extremely light residual contrast enhancement on magnetic resonance images due to the effects of microhemorrhages and scar tissue formation. These small enhancing lesions define an unconfirmed complete response. The aim of this study was to investigate the usefulness of carbon-11-labeled methionine (11C-Met) positron-emission tomography (PET) for determining the treatment response of PCNSL.. Data for 36 patients who were treated for PCNSL between 2011 and 2015 and underwent magnetic resonance imaging and 11C-Met PET were reviewed. Magnetic resonance imaging findings were classified as complete response, unconfirmed complete response, and tumor mass (a composite of partial response, stable disease and progressive disease). PET images were evaluated, standardized uptake values were quantified, and the tumor-to-normal tissue count ratio (TNR) was calculated. Receiver operating characteristic curves were generated to determine the optimal cutoff TNRs.. The optimal TNRs for differentiating complete response and unconfirmed complete response from tumor mass were 1.83 (area under the curve, 0.951) and 1.80 (area under the curve, 0.932), respectively. The corresponding sensitivity and specificity values for the diagnosis of tumor mass were 82.4 and 100%, respectively, in the complete response group and 85.3 and 85%, respectively, in the unconfirmed complete response group.. A TNR of ≥1.80 can aid in the detection of active PCNSL using 11C-Met PET. Thus, 11C-Met-PET may be a useful tool for accurate evaluation of the treatment efficacy in PCNSL.

Topics: Adult; Aged; Central Nervous System Neoplasms; Female; Humans; Magnetic Resonance Imaging; Male; Methionine; Middle Aged; Positron-Emission Tomography; ROC Curve; Treatment Outcome

The diagnosis of primary central nervous system lymphoma (PCNSL) in immunocompetent patients with atypical magnetic resonance (MR) findings such as disseminated lesions or no (non-enhancing) lesion is sometimes difficult because of mimicking other tumorous and non-tumorous diseases. Positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) and (11)C-methionine (MET) can measure the glucose and amino acid metabolism in the lesions and may provide useful information for diagnosing PCNSL in patients with such subtle MR findings.. We performed PET studies with FDG and MET in 17 histologically proven PCNSL and compared the uptake of FDG and MET qualitatively and quantitatively in the tumors between 12 typical and 5 atypical MR findings.. All typical PCNSL showed strong uptake of FDG and MET; however, visual analysis of FDG and MET uptake in atypical PCNSL was not very useful for finding lesions in the brain. Semiquantitative FDG and MET uptake values (SUVmax) and quantitative FDG influx rate constant (K ( i )) in the tumors are significantly lower in atypical PCNSL compared with those in typical PCNSL. These values obtained in the lesions with atypical MR findings were also not useful for differentiating PCNSL from other tumorous and non-tumorous diseases. The k (3) values evaluated by FDG kinetic analysis in atypical PCNSL were similar to those obtained in typical PCNSL.. Visual analysis of FDG and MET uptake in atypical PCNSL was not useful for finding the lesions in the brain. Semiquantitative and quantitative values obtained in the lesions with atypical MR findings were also not useful for differentiating PCNSL from other tumorous and non-tumorous diseases. The k (3) values evaluated by FDG kinetic analysis in atypical PCNSL may provide valuable information in the diagnosis of PCNSL.

Topics: Adult; Aged; Central Nervous System Neoplasms; Female; Fluorodeoxyglucose F18; Humans; Lymphoma; Magnetic Resonance Imaging; Male; Methionine; Middle Aged; Positron-Emission Tomography; Retrospective Studies