Multiphase contrast-enhanced CT of the liver with a multislice CT scanner

Our objective was to assess the effects of the injection rate of contrast material and of a 5% dextrose flush on enhancement in multiphase hepatic CT using a multislice CT scanner. Most patients had chronic hepatitis and/or liver cirrhosis. One hundred eighty examinations, in which two sequential acquisitions were performed during a single breath-hold followed by third- and fourth-pass acquisitions, were randomized into four protocols: contrast injection at 0.1 ml/kg body weight s(-1) over 21 s without and with a 30-ml flush in groups 1 and 2, respectively, and contrast injection at 0.07 ml/kg body weight s(-1) over 30 s without and with a flush in groups 3 and 4, respectively. Contrast enhancement in each acquisition was measured in the aorta, portal vein, and liver. The visualization of hepatic arterial branches was scored by visual assessment. The highest aortic enhancement was observed in the first-pass acquisition in all groups. At the higher injection rate (groups 1 and 2), aortic enhancement in the first-pass acquisition was significantly more intense, whereas portal venous and hepatic enhancement was significantly less intense. The use of a flush considerably improved aortic enhancement at the beginning of the second-pass acquisition. In the visual assessment of hepatic arterial branches, the protocols with the higher injection rate received significantly higher grades. Multislice CT permits the entire liver to be imaged during an almost exclusively arterial phase by shortening the injection duration for a given volume of contrast material.