Functional Imaging of SDHx-Related Head and Neck Paragangliomas: Comparison of 18F-Fluorodihydroxyphenylalanine, 18F-Fluorodopamine, 18F-Fluoro-2-Deoxy-D-Glucose PET, 123I-Metaiodobenzylguanidine Scintigraphy, and 111In-Pentetreotide Scintigraphy

Rationale: Accurate diagnosis of head and neck paragangliomas is often complicated by biochemical silence and lack of catecholamine-associated symptoms, making accurate anatomical and functional imaging techniques essential to the diagnostic process. Methods: Ten patients (seven SDHD, three SDHB), with a total of 26 head and neck paragangliomas, were evaluated with anatomical and functional imaging. This study compares five different functional imaging techniques [F-18-fluorodihydroxyphenylalanine (F-18-FDOPA) positron emission tomography (PET), F-18-fluorodopamine (F-18-FDA) PET/computed tomography (CT), F-18-fluoro-2-deoxy-D-glucose (F-18-FDG) PET/CT, I-123-metaiodobenzylguanidine (I-123-MIBG) scintigraphy, and In-111-pentetreotide scintigraphy] in the localization of head and neck paragangliomas. Results: Prospectively F-18-FDOPA PET localized 26 of 26 lesions in the 10 patients, CT/magnetic resonance imaging localized 21 of 26 lesions, F-18-FDG PET/CT localized 20 of 26 lesions, (111)-Inpentetreotide scintigraphy localized 16 of 25 lesions, F-18-FDA PET/CT localized 12 of 26 lesions, and 123I-MIBG scintigraphy localized eight of 26 lesions. Differences in imaging efficacy related to genetic phenotype, even in the present small sample size, included the negativity of 18F-FDA PET/CT and 123I-MIBG scintigraphy in patients with SDHB mutations and the accuracy of 18F-FDG PET/CT in all patients with SDHD mutations, as compared with the accuracy of 18F-FDG PET/CT in only one patient with an SDHB mutation. Conclusion: Overall, F-18-FDOPA PET proved to be the most efficacious functional imaging modality in the localization of SDHx-related head and neck paragangliomas and may be a potential first-line functional imaging agent for the localization of these tumors. (J Clin Endocrinol Metab 96: 2779-2785, 2011)