Performance Of 18F-FDG Research Articles

Diagnostic Performance of 18F-FDG PET/CT for Lymph Node Staging in Patients with Operable Non-small-cell Lung Cancer and Inflammatory Lung Disease

As (18)F-fluorodeoxyglucose (FDG) is taken up by inflammatory lymph nodes, it could be falsely interpreted as metastasis. Therefore, we evaluated the diagnostic ability of positron emission tomography/computed tomography (PET/CT) for lymph node staging of lung cancer when inflammatory lung disease coexisted. Patients with operable non-small-cell lung cancer and FDG-avid lymph nodes were retrospectively classified into two groups; those with inflammatory lung disease (ILD) and those without it (NILD). Receiver operating characteristic (ROC) curve analysis was performed for maximum standardized uptake value (SUVmax), pattern of FDG uptake, maximum Hounsfield unit, and size, and then the areas under the ROC curves (AUCs) were compared between subgroups. There were 124 patients (ILD/NILD = 38/86) and 396 FDG-avid lymph nodes (ILD/NILD = 140/256). The average number of FDG-avid lymph nodes was greater in ILD (3.7 vs. 2.9, p = 0.039), whereas the proportion of metastasis was higher in NILD (25.4% vs. 11.4%, p = 0.002). With all N1-N3 lymph nodes and the NILD group, the AUC values of all four parameters were significantly greater than 0.5 (p < 0.05), and SUVmax was the most valuable parameter for lymph node metastasis. However, in the ILD group, only the AUC value of SUVmax was significantly greater than 0.5. These results were reproduced when analyses were performed with N1-N2 lymph nodes. In conclusion, SUVmax was the most valuable PET/CT parameter for assessment of lymph node metastasis in patients with operable non-small-cell lung cancer. In addition, it was the only valuable parameter when inflammatory lung disease coexisted.

Optimization of semi-quantification in metabolic PET studies with 18F-fluorodeoxyglucose and 11C-methionine in the determination of malignancy of gliomas

The treatment of the glioma patient depends on the nature of the lesion and on the aggressiveness of the tumor. The management of gliomas continues to be a challenging task, because morphological neuroimaging techniques do not always differentiate them from nontumoral lesions or high grade tumors from low grade lesions. Positron Emission Tomography (PET) offers the possibility of the in vivo quantitative characterization of brain tumors. Despite decades of useful application of PET in the clinical monitoring of gliomas, no consensus has been reached on the most effective image analysis approach for providing the best diagnostic performance under heavy-duty clinical diagnostic circumstances. The main objective of the present study was to find and validate optimal semi-quantitative search strategies for metabolic PET studies on gliomas, with special regard to the optimization of those metabolic tracer uptake ratios most sensitive in predicting histologic grade and prognosis. 11C-Methionine ( 11C-Met, n = 50) and/or 18F-Fluorodeoxyglucose ( 18F-FDG, n = 33) PET measurements were performed in 59 patients with primary and recurrent brain gliomas (22 high grade and 37 low grade tumors) in order to correlate the biological behavior and 11C-Met/ 18F-FDG uptake of tumors. Data were analyzed by region-of-interests (ROI) methods using standard uptake value calculation. Different ROI defining strategies were then compared with each other for two of the most commonly used metabolic radiotracers, 18F-FDG and 11C-Met, in order to determine their usefulness in grading gliomas. The results were compared to histological data in all patients. Both ANOVA and receiver operating characteristic (ROC) analysis indicated that the performance of 18F-FDG was superior to that of 11C-Met for most of the ratios. 18F-FDG is therefore suggested as the tracer of choice for noninvasive semi-quantitative indicator of histologic grade of gliomas. 11C-Methionine has been suggested as a complimentary tracer, useful in delineating the extent of the tumor. The best diagnostic performance was obtained by calculating the ratio of the peak 18F-FDG uptake of the tumor to that of white matter ( p < 0.001; ANOVA). This metabolic tracer uptake ratio is therefore suggested as an easily obtained semi-quantitative PET indicator of malignancy and histological grade in gliomas.