Value of 123I-MIBG Scintigraphy in Paraganglioma

The aim of the study was to evaluate the current role of (123)I-MIBG scintigraphy in the detection and follow-up of patients with paragangliomas.

117 patients were referred for diagnostic (123)I-MIBG scintigraphy based on a strong clinical suspicion, positive familial history and genetic testing, or for follow-up of paragangliomas.(123)I-MIBG images were analyzed and correlated with (111)In-octreotide scintigraphy, CT or MRI results. Accuracy of the imaging method was calculated per patient and per tumor per site.

A total of 117 patients were referred for (123)I-MIBG diagnostic imaging; 80 patients were diagnosed with paraganglioma; 66 patients had a single neuroendocrine tumor and 14 patients multiple tumors. The total number of all lesions in these patients was 172. (123)I-MIBG scintigraphy demonstrated 65 lesions in 56 patients (overall sensitivity: 56.3%, specificity: 84%). Lesion-per-site analysis revealed that sensitivity and specificity significantly varied per tumor site (lowest sensitivity for the head and neck: 17.5% and lowest specificity for the abdomen: 87.5%). Hormones were elevated in 85 patients: 55 (123)I-MIBG tumors were positive and 35 tumors were negative. In 16 patients (13.7%) with a genetic burden and a single neuroendocrine tumor, (123)I-MIBG whole-body imaging was successful at detecting a second tumor. In 2 patients (1.7%) with paragangliomas, (123)I-MIBG unexpectedly detected metastases, so the restaging was properly done.

(123)I-MIBG scintigraphy remains important in pheochromocytoma and functioning neuroendocrine tumors. The value of (123)I-MIBG scintigraphy is high in familial syndromes with multiple neuroendocrine tumors at different sites, multifocal tumors, and relapsing and metastatic disease.