Novel connecting tube for saline chaser in contrast-enhanced CT: The effect of spiral flow of saline on contrast enhancement

Objective: To evaluate the effect of a newly developed connecting tube, which generates a spiral flow of saline, on aortic and hepatic contrast enhancement during hepatic-arterial phase (HAP) and portal venous phase (PVP) computed tomography (CT). Methods: Eighty patients were randomly assigned to one of two protocols: with a new or a conventional tube. The contrast material (600 mgI/kg) was delivered over 30 s; this was followed by the administration of 25 ml saline solution delivered at the same injection rate as the contrast material. Unenhanced and contrast-enhanced CT images of the upper abdomen were obtained. We calculated the changes in the CT number (â̂†HU) for the aorta during HAP and PVP, and for the liver during PVP. We compared â̂†HU between protocols. Results: The mean â̂†HU for the abdominal aorta during HAP was significantly higher with the new tube protocol than with the conventional tube protocol (322 ± 53 vs. 290 ± 53, P < 0.01). There were no significant differences in the mean â̂†HU for the abdominal aorta and liver during PVP between the two protocols (P > 0.05). Conclusion: The new connecting tube increased the effect of a saline chaser and significantly improved aortic enhancement during HAP.