[Significance of false-positive findings of somatostatin receptor scintigraphy in diagnosis of neuroendocrine tumors of the gastroenteropancreatic system]

Localization of gastroenteropancreatic neuroendocrine tumors with conventional imaging techniques can be difficult. With the advent of the somatostatin-receptor scintigraphy the diagnosis of these could be improved. In this study 76 patients with immunohistologically proven neuroendocrine tumors were analysed by comparing somatostatin-receptor scintigraphy with conventional imaging techniques. Somatostatin-receptor-positive lesions were observed in 61 of all patients. Conventional imaging techniques (transabdominal ultrasonography, computerized tomographic scanning of the abdomen, magnetic resonance imaging of the abdomen) revealed neuroendocrine tumors in 42 patients (69%). A follow up of 19 patients with initially false positive somatostatin-receptor scintigrams showed that at least 6 patients had escaped the initial diagnosis by conventional techniques. All in all, our data support previous findings and demonstrate that somatostatin-receptor scintigraphy is a safe and sensitive procedure for in vivo imaging of gastroenteropancreatic neuroendocrine tumors. In addition, in certain cases, somatostatin-receptor scintigraphy is able to detect tumors that had escaped conventional imaging techniques.