[Imaging techniques in the diagnosis of neuroendocrine tumors]

Diagnostic work-up of neuroendocrine tumors (NET) includes clinical assessment, biochemical testing and imaging procedures. Endoscopic investigations are indicated for identification of NET in the gastrointestinal tract and the bronchopulmonary tree. Transabdominal ultrasound has a relatively low sensitivity in small lesions, but intraoperative ultrasound improves intraoperative detection of lesions. Endoscopic ultrasonography has a high sensitivity to detect tumors in pancreatic head and duodenal wall. Radiological procedures, including computed tomography (CT) and magnetic resonance imaging (MRI), are well established techniques for the investigation of primary tumors, metastatic lesions, associated malignancies and follow-up after surgical or medical treatments. Somatostatin receptor scintigraphy (SRS) is based on the presence of somatostatin receptors in a great proportion of NET. PET is a functional imaging technique that reflects tumor metabolism. A multimodality approach, including CT, MRI, SRS, ultrasound and endoscopy, is nowadays recommended for detecting these tumors.