Feasibility study on liver CT contrast-enhanced scan with low dose of radiation and contrast agent

Abstract

To explore the feasibility for liver contrast-enhanced CT scan with low dose of radiation and contrast agent in clinical. A total of 180 cases were randomly divided into group I (low concentration of contrast agent, 270 mgI/mL of iodixanol) and group II (high concentration of contrast agent, 320 mgI/mL of iodixanol). Three scan conditions (A: 120 kV, 300 mA; B: 100 kV, 400 mA; and C: 100 kV, 300 mA) were randomly distributed in 3 phases (arterial phase, venous phase and delay phase) for liver scans in each group. The effective radiation dose (ED), image CT values and quality of images (image of noise (NI), the image signal to noise ratio (SNR), contrast to noise ratio (CNR), and overall image quality (OIQ) scores were recorded and analyzed. ED values for the group C in the total samples were decreased by 38%, 40% and 41%, respectively compared to the group A in contrast-enhanced scan for 3 phases. The image quality was significantly different (P<0.05); ED values in the group B were decreased by 18%, 20% and 20%, respectively compared to group A in contrast-enhanced scan for 3 phases, and there were no significant differences (P>0.05) in image quality. There were significant differences between the group I and the group II in CT values at the same scanning parameters and scanning phases (P<0.05), but the image quality was not obviously different; there was no significant difference between the group A-II and the group B-I as well as the group C-I in image CT values, and there was also no significant difference between the group A-II and the group B-I in image quality (P>0.05); however the differences in image quality were statistically significant between the group A-II and the group C-I (P<0.05). Reduction of the tube voltage (to improve the tube current) combined with the low-dose contrast agent can not only reduce the radiation dose and contrast agent dose but also meet the needs of double-low liver contrast-enhanced CT scan.