Gastrinomas: comparison of MR imaging with CT, angiography, and US.

Abstract

In this prospective study, magnetic resonance (MR) imaging was used to localize gastrinoma in 24 patients with Zollinger-Ellison syndrome. The results were confirmed by means of either surgery or percutaneous liver biopsy and compared with results of computed tomographic (CT) scanning, selective abdominal angiography, and abdominal ultrasound (US). For primary extrahepatic gastrinoma (intra-or extrapancreatic), MR imaging had a sensitivity of 20% and a specificity of 100%, with a positive predictive value of 100% and a negative predictive value of 11%. For metastatic gastrinoma in the liver, MR imaging had a sensitivity of 43% and a specificity of 100%, with a positive predictive value of 100% and a negative predictive value of 81%. The ability of MR imaging to depict extrahepatic gastrinomas was directly related to tumor size; no tumors smaller than 1 cm were detected, and 50% of tumors 3 cm or larger were detected. MR imaging was as effective as abdominal US but less effective than either CT scanning or selective abdominal angiography for the detection of extrahepatic gastrinoma. In seven patients with hepatic gastrinoma, three gastrinomas were detected with MR imaging and with abdominal US, while five were detected with CT scanning and with selective abdominal angiography. These results indicate that, at the present time, MR imaging is generally not useful in the initial attempt to localize gastrinomas.

Gastrinoma (Duodenal and Pancreatic)

“…SRS’s sensitivity is equal to all conventional imaging studies combined [34]. For SRS, as well as all conventional studies, tumor size is an important variable and tumors <1 cm are missed in >50% of cases [41, 42]. Therefore, because most duodenal tumors are <1 cm they are frequently missed.…”

Well-Differentiated Duodenal Tumor/Carcinoma (Excluding Gastrinomas)

“…Studies in duodenal gastrinomas demonstrate that conventional imaging studies detect ≤15% of gastrinomas <1 cm in diameter, 20–50% 1–3 cm in diameter and 95% >3 cm in diameter [48, 50, 53]. …”

Management of Gastro-intestinal Neuroendocrine Tumors with Liver Metastases: A Comprehensive Review

“…In one series, primary tumors were localized in 81-96% of cases using radiological and/or nuclear medicine imaging [13]. Ultrasonography, CT, and MRI, respectively has been found to detect only 9%, 31%, and 20% of primaries [14].…”

“…[14] Liver metastases may be detected using US, CT, and MRI with sensitivities of 46%, 42%, and 43%, respectively [14]. In the past, selective angiography was used to detect hepatic metastases and had a reported sensitivity of 86% but this is no longer used, since the combination of SRS and CT/MRI detects 96% of liver metastases [19].…”

“…These lesions may become isodense with normal hepatic parenchyma in scans obtained during the portal venous or equilibrium phase. Accordingly, if metastatic carcinoid tumor is suspected, hepatic arterial phase imaging should be obtained [14].…”