Abstract: To explore the feasibility of low dose combined with low concentration contrast agent in 320-row coronary computer tomography (CT) angiography. 153 patients who underwent coronary computer tomography angiography were prospectively collected. 49 patients were included in group A, 52 patients were included in group B, and 52 patients were included in group C. The tube voltage of three groups were 80 kV, 100 kV and 100 kV, respectively. The concentration of contrast agent of three groups were 300 mgI/mL, 300 mgI/mL and 350 mgI/mL, respectively. Statistical data are shown, there were no significant differences in the CT values of the middistal left anterior descending (LAD) and the distal left circumflex (LCX) of three groups (P>0.05), and the CT values of the other segments in group A were higher than those in group B and C (P<0.05). There were no significant differences in the noise values of the middistal LAD, LCX and right coronary artery (RCA) in the three groups (P>0.05). There were no significant differences in signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and subjective scores among the three groups (P>0.05). The radiation dose of group A was significantly lower than that of group B and group C (P<0.05). In conclusion, low dose combined with low concentration contrast agent can be used in 320-row coronary CTA, which is conducive to reducing the harm of X-ray radiation and high concentration of contrast agent to patients.

Key words: coronary computer tomography angiography, 320-row computer tomography, low dose, low concentration contrast agent