Metastatic Pheochromocytoma/Paraganglioma: Diagnostic Performance of Functional Imaging (18F-Fluoro-L-DOPA-, 68Ga-DOTA- and 18F-Fluoro-Deoxyglucose-Based PET/CT) and of 123I-MIBG Scintigraphy in 57 Patients and 527 Controls During Long-Term Follow-Up

Background: Large-scale data on the diagnostic performance of functional imaging in metastatic pheochromocytoma/paraganglioma (PPGL) are scarce. Objective: To analyze the diagnostic accuracy of functional imaging for the assessment of metastases during long-term follow-up (FU). Design: Retrospective cohort study, 1991–2025. Setting: Referral center. Outcomes: Sensitivity and specificity of 123MIBG-, 18F-DOPA-, 68GaDOTA-based and 18FDG PET/CT. Patients: Patients with metastatic PPGL and without PPGL, ≥1 functional imaging prior to first diagnosis and/or during FU and FU ≥ 3 months. Results: 59 123MIBG-, 101 18F-DOPA-, 11 18FDG- and 74 68GaDOTA-based PET/CT were performed in 57 patients with metastatic PPGL and 37 123MIBG-, 323 18F-DOPA-, 259 18FDG- and 641 68GaDOTA-based imaging in 527 patients without PPGL. FU was 11.6 ± 11.4 and 5.1 ± 4.7 years, respectively. Sensitivity for the detection of all metastases (total cohort) by patient-based analysis was comparable between 18F-DOPA (77%), both 68GaDOTA-based tracers combined (67%) and 123MIBG (72%); lesion-based analysis was better for 18F-DOPA (94%) than for 68GaDOTA (85%) and 123MIBG (67%). Specificity (patient- and lesion-based) of 18F-DOPA vs. 68GaDOTA (96–99%) was comparable and better than 123MIBG (73%) and 18FDG (75%). Conclusions: Sensitivity of 18F-DOPA was superior to 68GaDOTA for the detection of all and bone metastases in the total cohort and in patients with PCC, that of 68GaDOTA was better for bone metastases with PGL, specificity was comparable and for both was better than for 18FDG and 123MIBG. Given the beneficial pharmaceutical properties and favorable diagnostic performance, 18F-DOPA may be a good alternative to 68GaDOTA-based tracers for the functional imaging of metastatic PPGL.