The Yale journal of biology and medicine
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There are six major steps in the management of patients with neuroendocrine tumors (NETs) (carcinoids and pancreatic endocrine tumors). One of the steps that is increasing in its importance is the need to assess primary tumor location and tumor extent in these patients. Without such information, it is not possible to adequately manage these patients. ⋯ SRS correctly identified 93 percent of the patients with liver metastases and was not positive in any patient with a hemangioma, suggesting it was not a liver metastases. SRS had greater negative and positive predictive value than conventional studies. Based on these two studies, and SRS's greater sensitivity and fiscal considerations, it is proposed that SRS should be the initial tumor imaging study in all NETs except insulinomas, and algorithms for the use of other localization studies in both NETs and insulinomas are proposed.
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Comparative Study
Comparative analysis of diagnostic techniques for localization of gastrointestinal neuroendocrine tumors.
In vitro studies have shown that gastroenteropancreatic tumors, with the exception of insulinomas, have a high density of somatostatin receptors and can be imaged in vivo using somatostatin receptor scintigraphy (SRS) with either [123I-Tyr3]octreotide or [111In DTPA,DPhe1]octreotide. However, the sensitivity in relation to conventional imaging studies (ultrasound, CT, MRI, angiography) remains unclear. To address this question, we performed a prospective study of 80 patients with gastrinomas where SRS was compared with other conventional imaging techniques for detecting extrahepatic gastrinomas or liver metastases. ⋯ Therefore, the results of EUS in various studies containing patients with PETs are compared to those with SRS and conventional imaging studies. These data suggest that EUS is the first choice of localization methods for detecting insulinoma, which is an intrapancreatic tumor in almost all cases. In other PETs there still is not sufficient data to establish the relative roles of EUS and SRS.