RESUMO
The ability of short injection duration of contrast material to reduce the total injection volume in 64-detector row CT coronary angiography was investigated. 45 patients were divided into three groups: (i) those receiving 0.8 ml kg(-1) of contrast material (350 mgI ml(-1)) injected with a fixed duration of 14 s (Group A; n = 16); (ii) those receiving 0.8 ml kg(-1) of contrast material injected with a fixed duration of 10 s (Group B; n = 15); and (iii) those receiving 0.7 ml kg(-1) of contrast material injected with a fixed duration of 10 s (Group C; n = 14). All patients then received 20 ml of saline. Contrast densities of the ascending aorta and proximal and distal coronary arteries were assessed where vessel diameters were >2.0 mm. The mean enhancement value in the ascending aorta for Group B was significantly higher than that for Groups A and C (p<0.05), whereas there was no significant difference between Groups A and C. All enhancement values in the coronary arteries were higher than 250 Hounsfield units. The mean enhancement value for each coronary artery in Group B was significantly higher than that for Group A (p<0.05), whereas there was no significant difference between Groups A and C. In conclusion, a short injection duration allows a reduction in the total volume of contrast material from 0.8 ml kg(-1) to 0.7 ml kg(-1) while a steady contrast enhancement is maintained in the ascending aorta and coronary arteries.
