Thickening at the root of the superior mesenteric artery on sonography: evidence of vascular involvement in patients with cancer of the pancreas.

Abstract

Thickening of the root of the superior mesenteric artery (SMA) was studied by using preoperative sonography in 23 patients with pancreatic cancer and in 10 healthy control subjects. Of the 23 with cancer, 11 had neoplastic involvement of the SMA and 12 did not. Prominent thickening of the area around the SMA with (six patients) or without (five patients) decreased echogenicity compared with the adjacent retropancreatic connective tissue was observed in patients with involvement of the SMA, a finding called the "cuff sign." Mean thickness of the periarterial area in the cancer patients with and without involvement of the SMA and in control subjects were 8.5 mm, 4.0 mm, and 2.9 mm, respectively. With an upper limit of normal of 7.0 mm for the thickness of the SMA, the sensitivity, specificity, and overall accuracy of this sign in the evaluation of involvement of the SMA were 91%, 100%, and 96%, respectively. Decreased echogenicity of the periarterial area was not observed in patients without involvement of the SMA or in control subjects. Our results show that sonographic evidence of periarterial thickening of the root of the SMA (cuff sign), especially with decreased echogenicity, is a reliable finding of tumor infiltration of the SMA in patients with pancreatic carcinoma.