Vascular contact with soft tissue: a sign of mesenteric masses at computed tomography

PURPOSE: To evaluate prevalence of mesenteric vascular contact at routine computed tomography (CT) and evaluate its value for distinguishing missed mesenteric masses from adjacent bowel. MATERIALS AND METHODS: We identified 18 abdominopelvic CT scans of 9 patients in whom mesenteric masses were missed on the prospective CT reports. We recorded the long-axis diameter of the masses, time interval to eventual detection, and presence of vascular contact (fat plane obscuration) with a mesenteric vessel greater than 1 mm in diameter. We also retrospectively identified 129 consecutive abdominopelvic CT scans of nononcology patients and recorded all locations of vascular contact between a mesenteric vessel greater than 1 mm in diameter and adjacent bowel. RESULTS: In the 18 CT examinations where mesenteric masses were missed, the mean long-axis diameter was 2.9 cm, and time between the initial CT scan and first discovery was 12 months. Mesenteric vessels contacted the masses in 17 (94%) of 18 scans. In the 129 nononcology patients, vascular contact was rarely seen with bowel distal to the proximal jejunum (6 had vascular contact with distal jejunum, 5 with ileum, and 0 with colon). However, the third and fourth duodenal portions showed vascular contact with the superior mesenteric vessels in 36 (28%) and 12 patients (9.4%), respectively, and with the inferior mesenteric vessels in 58 patients (48%). CONCLUSIONS: At CT, mesenteric vessels greater than 1 mm in diameter rarely contact bowel other than the duodenum and proximal jejunum; however, they often contact mesenteric masses. At CT scan review, inspection of the mesenteric vessels may facilitate mesenteric mass identification.