Accuracy of 18F-FDOPA Positron Emission Tomography and 18F-FETPositron Emission Tomography for Differentiating Radiation Necrosis from Brain Tumor Recurrence

BACKGROUND: Distinguishing radiation necrosis from brain tumor recurrence remains challenging. We performed a meta-analysis to assess the diagnostic accuracy of 2 different amino acid tracers used in positron emission tomography/ computed tomography scans: F-18-FDOPA (6-[F-18]-fluoro-L-3,4-dihydroxyphenylalanine) and F-18-FET (O-(2-F-18-fluoroethyl)-L-tyrosine). METHODS: We searched for studies in 3 databases: PubMed, Embase, and Chinese Biomedical databases. The data were extracted from eligible studies and then processed with heterogeneity test, threshold effect test, and calculations of sensitivity, specificity, and area under the summary receiver operating characteristic curve. Meta-regression and subgroup analyses were performed to explore the source of heterogeneity. RESULTS: A total of 48 studies (F-18-FDOPA, n = 21; F-18-FET, n = 27) were included. Quantitative synthesis determined pooled weight values in the F-18-FDOPA and F-18-FET groups: sensitivity, 0.85 versus 0.82; specificity, 0.77 versus 0.80; diagnostic odds ratio, 21.7 versus 23.03; area under the curve (AUC) values, 0.8771 versus 0.8976 (P = 0.46). Moreover, the type of tumor was identified as the possible source of the significant heterogeneity (I-2 = 52%; P = 0.003) found in the F-18-FDOPA group. In meta-regression and subgroup analyses, F-18-FDOPA showed better diagnostic accuracy in patients with glioma compared with patients with brain metastases (AUC values, 0.9691 vs. 0.837; P < 0.01). F-18-FDOPA also showed a significant advantage in the diagnosis of glioma recurrence compared with F-18-FET (AUC values, 0.9691 vs. 0.9124; P = 0.015). CONCLUSIONS: Both F-18-FDOPA and F-18-FET exhibit moderate overall accuracy in diagnosing brain tumor recurrence from radiation necrosis. However, F-18-FDOPA is more adept at diagnosing glioma recurrence compared with brain metastases, and it is more effective than F-18-FET in diagnosing glioma recurrence.