Imaging secondary neuroendocrine tumours of the liver: comparison of I123 metaiodobenzylguanidine (MIBG) and In111-labelled octreotide (Octreoscan).

Functional imaging of neuroendocrine tumours with Octreoscan and I123-metaiodobenzylguanidine (MIBG) is important for assessment prior to various therapies and assessing response. The two imaging methods have not been directly compared in hepatic neuroendocrine tumours. Patients (n = 18) were studied with both imaging techniques. The sensitivity of Octreoscan was 94%, and that of MIBG 39%. No previously occult primary sites were detected. Concurrent octreotide therapy did not reduce the sensitivity of Octreoscan. Widespread bone metastases were seen in two post-liver-transplant patients using Octreoscan. Octreoscan is a sensitive means of detecting hepatic neuroendocrine tumours, and the more specific technique. MIBG has poor sensitivity, reducing its clinical utility. Therapy with I131-MIBG is likely to be applicable to relatively few patients.