The use of helical CT and CT angiography to predict vascular involvement from pancreatic cancer: Correlation with findings at surgery

OBJECTIVE. The purpose of this study was to test the accuracy of helical CT with and without CT angiography to predict vascular involvement from pancreatic cancer and correlate the resultant images with findings at surgery. SUBJECTS AND METHODS. Helical CT and CT angiography was done in 84 patients who had adenocarcinoma of the pancreas to refine an integrated helical CT angiography protocol. Of these patients, 38 underwent radical pancreatoduodenectomy. Vessel integrity of the superior mesenteric artery, superior mesenteric vein, and portal vein was assessed prospectively on both axial CT scans and CT angiograms and correlated with findings at surgery and in particular with the ability of the surgeon to dissect the tumor from these vessels along the vascular planes. RESULTS. CT angiograms were obtained in 82 (98%) of 84 studies. Of the 38 patients pancreatoduodenectomy, resection was aborted in 11 (29%) because of vascular encasement. Compared with axial CT images, CT angiography was more accurate at revealing unresectable cases. In all but one of 11 patients with vessel encasement (narrowing of the lumen) revealed on CT angiography, the lesion was unresectable. Vessel encasement was shown in only two of these 11 patients on axial CT images (of these two patients, one underwent tumor resection.) The negative predictive value of a resectable tumor was 96% for CT angiography and axial helical CT compared with 70% for axial helical CT images alone (p =.021). CONCLUSION. Helical CT with CT angiography of the pancreas provides useful information about local vascular involvement from pancreatic carcinoma. Compared with conventional axial helical CT, the addition of CT angiography improves radiologists' ability to predict the resectability of pancreatic tumors.