Noninvasive imaging of insulinomas and gastrinomas with endoscopic ultrasonography and somatostatin receptor scintigraphy

Background. Classic morphological techniques are of limited value for imagi ng endocrine duodenopancreatic tumors, and invasive procedures such as intr aarterial stimulation are often used. Two noninvasive procedures, endoscopi c ultrasonography (EUS) and somatostatin receptor scintigraphy (SRS), were recently described with promising results. Methods. In this study we correlated the results of preoperative EUS (n = 3 4) and SRS (n = 30) with operative findings in patients with histologically proven insulinoma (n = 20) or gastrinoma (n = 21). Results. The sensitivity and positive predictive value (PPV) of EUS were re spectively 77% and 94% for pancreatic tumors (insulinomas and gastrinomas) 40% and 100 % for duodenal gastrinomas, and 58% and 78% for metastatic lymp h nodes. The sensitivity and PPV of SRS for insulinoma were 60% and 100 %, respectively. In patients with gastrinoma, the sensitivity and PPV of SRS w ere respectively 25 % and 100 % for pancreatic gastrinomas, 72 % and 100 % for duodenal gastrinomas or periduodenal metastatic lymph nodes, and 67% an d 80 % for liver metastasis. In patients with multiple endocrine neoplasia, neither one of the two techniques detected all tumors. Overall sensitivity of combined EUS and SRS was 89 % for insulinoma (n = 9) and 93 % for gastr inoma (n = 14). Conclusions. EUS and SRS for gastrinomas and insulinomas should be consider ed as the initial preoperative imaging-procedures and may render invasive p rocedures unnecessary for most patients.