Midgut neuroendocrine tumors: imaging assessment for surgical resection.

Midgut neuroendocrine tumors (MNETs) are rare, and the primary tumor is usually small and difficult to visualize at imaging. Patients often present late with extensive liver and nodal metastases and may experience symptoms secondary to the release of active substances by the primary tumor, such as serotonin and its metabolites, which have local and systemic effects. Locally, this causes desmoplasia and vascular encasement and may lead to small bowel obstruction and ischemia, with significant morbidity and mortality. Systemically, the release of active substances into the circulation can cause flushing, diarrhea, and abdominal pain (carcinoid syndrome); these substances can be detected in urine and blood serum and used as markers for diagnosis and treatment follow-up. MNETs retain expression of specific peptide receptors such as somatostatin receptors, which will bind to synthetic somatostatin analogs such as octreotide. This feature is useful for functional imaging of patients with MNETs and for peptide receptor radionuclide therapy using somatostatin analogs. Resection of the primary tumor is advocated, even in patients with extensive metastases, because it may prevent development of local complications, can help control systemic symptoms, and has been shown to confer some survival advantage. Computed tomography and functional imaging are used to identify the primary tumor and assess its resectability. The main factors governing resectability are patient comorbidities (eg, carcinoid heart disease), vascular involvement, and desmoplasia.

Interventional radiology in liver transplantation.

Radiology is a key specialty within a liver transplant program. Interventional techniques not only contribute to graft and recipient survival but also allow appropriate patient selection and ensure that recipients with severe liver decompensation, hepatocellular carcinoma or portal hypertension are transplanted with the best chance of prolonged survival. Equally inappropriate selection for these techniques may adversely affect survival. Liver transplantation is a dynamic field of innovative surgical techniques with a requirement for interventional radiology to parallel these developments. This paper reviews the current practice within a major European center for adult and pediatric transplantation.