Is endoscopic ultrasonography more sensitive than magnetic resonance imaging in detecting and localizing pancreatic neuroendocrine tumors?

To compare endoscopic ultrasonography (EUS) and magnetic resonance imaging (MRI) in terms of their sensitivities to localize pancreatic neuroendocrine tumors (pNET) preoperatively. Systematic analysis of the literature; sensitivity of EUS and MRI in insulinomas and pancreaticoduodenal NETs in multiple endocrine neoplasia type 1 (MEN1) in series of at least 20 subjects referring to tumors confirmed by surgery and histopathology. Other imaging methods reported were also assessed. Eighteen publications on insulinomas (782 cases) could be analyzed, no study in MEN1 fulfilled the inclusion criteria and compared EUS to MRI. Data quality was moderate: all publications referred to case series. Mean correct detection / localization rates (sensitivity) were calculated: EUS 80%, MRI 66%, computed tomography 63%, angiography 52%, somatostatin receptor scintigraphy 42%, ultrasonography 23%; arterial calcium stimulation with hepatic venous sampling regionalized correctly in 80%. EUS seems to be more sensitive than MRI in localizing pancreatic neuroendocrine tumors. If a specialized endosonographist is available, EUS is the preferable imaging procedure. Otherwise, MRI is a suitable alternative.