Teardrop superior mesenteric vein: CT sign for unresectable carcinoma of the pancreas

OBJECTIVE. Our objective was to investigate whether a tethered, teardrop-shaped superior mesenteric vein (SMV) is a reliable CT indicator of unresectable adenocarcinoma of the head of the pancreas. MATERIALS AND METHODS. CT scans of 92 patients with high suspicion for pancreatic head adenocarcinoma were retrospectively reviewed by two radiologists who were unfamiliar with the patients' outcomes. The reviewers were asked to assess whether the teardrop SMV sign was present or not; agreement was reached by consensus. Teardrop SMV was considered absent in patients with an obstructed vessel. RESULTS. Of 92 patients, 30 had a normal pancreas without a teardrop SMV. A mass in the head of the pancreas was seen in all 62 patients with cancer. Of these 62 patients, 30 (seven with teardrop SMV) were deemed to have inoperable disease by standard CT or clinical criteria. The remaining 32 patients underwent surgery; only 15 of these 32 had successful pancreatoduodenectomies. No patient with resectable tumor had an unequivocal teardrop SMV sign. In 17 patients (13 with teardrop SMV), resection of the tumor could not be accomplished because of vascular encasement (n = 12) or metastasis (n = 5). Added to conventional signs, teardrop SMV significantly increased CT's sensitivity (from 60% to 91%) and accuracy (from 79% to 95%) without significantly changing its specificity (from 100% to 98%) for resectability of pancreatic head cancer. CONCLUSION. The teardrop SMV is a reliable sign for predicting unresectability of adenocarcinoma of the head of the pancreas and can significantly contribute to preoperative planning.