Usefulness of saline chaser to reduce the dose of contrast material for abdominal ct in normal dogs

Abstract

Saline chaser has been reported to allow a significant reduction of contrast material dose and artifacts during computed tomography (CT) examination in human medicine. However, relatively few reports have been reported in dogs. This study assess the extent of dose reduction in intravascularly injected contrast material with the use of a saline chaser in abdominal CT without decreasing the vascular and hepatic parenchymal enhancement in clinically normal dogs. Five beagle dogs underwent abdominal CT scans. Three injection protocols were applied: iohexol injection (600 mg I/kg) without saline chaser (protocol 1), 30% lower dose (420 mg I/kg) of the same iohexol injection followed by 10 ml saline solution (protocol 2), and 40% lower dose (360 mg I/kg) of the contrast material followed by 10 ml saline solution (protocol 3). A dynamic CT scan at the level of the porta hepatis was conducted for 40 seconds. Each dog underwent the 3 protocols twice (total 6 scans). Attenuation values were obtained from the aorta, portal vein, and liver parenchyma. The maximum enhancement values (MEV) in protocol 2 were significantly higher than those in protocols 1 and 3 in the aorta

no significant difference was seen in the portal vein in all protocols. The MEVs recorded from the liver parenchyma in protocols 1 and 2 were significantly higher than those obtained in protocol 3. In this study, the application of saline chaser with a reduced dose of contrast material did not affect vessel enhancement. In conclusion, the use of a saline chaser for abdominal CT is recommended because it allows 30% reduction in the dose of contrast material without a significant decrease in the vascular and hepatic parenchymal enhancement.