MRI in insulinomas: preliminary findings.

After establishing the diagnosis of an insulinoma, most surgeons prefer preoperative localization. Selective arteriography is usually considered the gold standard for this purpose. Recently, computed tomography (CT) and preoperative US have contended the role to angiography. MRI has been used in few cases of endocrine pancreatic tumors, and its role in this particular field has to be defined. Between November 1988 and September 1990 we evaluated 7 adult patients who had had surgery in our Surgical Department. Eight tumors were resected in 6 patients who were cured; in an 18-year-old woman surgical treatment was unsuccessful. Arteriography, CT, preoperative US, MRI and intraoperative US detected 2, 6, 6, 5 and 6 tumors, respectively. Two insulinomas (0.2 and 0.7 cm) were found at histologic examination in resected specimen. The ability of intraoperative US and careful surgical exploration to resolve more than 90% of cases makes the preoperative use of arteriography and CT of questionable value. If further experience confirms these findings, US and MRI may suffice.