DELAYED INTRAVENOUS CONTRAST-MEDIUM WASHOUT FROM THE SMALL-BOWEL IN PATIENTS WITH PANCREATIC-CARCINOMA AND SPLANCHNIC VENOUS INVASION

Purpose: Our goal was to determine whether splanchnic venous invasion by pancreatic carcinoma causes any detectable delay in contrast medium clearance from the small bowel, reflected in alterations in small bow el (SBe), portal vein (PVe), or hepatic (He) enhancement on contrast-e nhanced spiral CT. Method: The values of SBe, PVe, and He were determi ned from axial images obtained during performance of an abdominal spir al CT in 20 patients with pancreatic adenocarcinoma. SBe/PVe and SBe/H e, felt to reflect intravenous contrast agent washout from the small b owel wall, were also calculated. Nine patients had splanchnic venous i nvasion (Group 1), and 11 were free of splanchnic venous involvement ( Group 2) as determined by surgery or angiography. Similar measurements and ratios were performed in 10 patients with normal spiral CT scans to serve as controls (Group 3). Results: A significant increase in SBe (p < 0.05), SBe/PVe (p < 0.01), and SBe/He (p < 0.05) and decrease in PVe (p < 0.01) were found in patients with invasion when compared wit h those without invasion and controls, while these parameters were sim ilar in the last two groups. Individual SBe/PVe ratios in Group 1 were consistently elevated when compared with even the highest individual values in Groups 2 and 3. Conclusion: A detectable increase in SBe and decrease in PVe exist when comparing patients with and without splanc hnic venous invasion by pancreatic adenocarcinoma. This is possibly th e result of splanchnic congestion causing a delay in contrast medium w ashout from the small bowel wall. The SBe/PVe ratio, felt to be an ind icator of contrast agent washout, may be used as an aid during spiral CT for pancreatic adenocarcinoma to determine the status of the splanc hnic vasculature in equivocal cases.