[Imaging methods in diagnosis of neuroendocrine tumors of the gastrointestinal tract].

Abstract

Neuroendocrine tumors of the gastroenteropancreatic system represent a group of tumors with various diagnostic problems. Especially detection of primary tumor lesions is often difficult. Endoscopic ultrasonography is a relatively new imaging procedure localizing insulinomas preoperatively in about 90% of cases. Thus, previously used invasive preoperative imaging methods are usually unnecessary. The combination of endoscopic ultrasonography and somatostatin receptor scintigraphy allows visualization of gastrinomas in 90% of cases. Somatostatin receptor scintigraphy can also visualize metastatic lesions of gastrinomas and carcinoids in the whole body with high accuracy. In surgical management of a gastrinoma, duodenal transillumination and intraoperative ultrasound should be performed in all cases to exclude small duodenal or periduodenal, extrapancreatic tumors. US, CT, and MRI should be mainly used to exclude local and distant metastases. Angiography is helpful in detecting anatomical variations of abdominal vessels preoperatively. Due to the excellent results of endoscopic ultrasonography and somatostatin receptor scintigraphy in localizing insulinomas and gastrinomas, transhepatic portal venous sampling appears to be obsolete.