RESUMEN
0bjective To determine the optimal contrast protocols for 64.slice spiral CT coronary angiography in order to reduce the volume of contrast injection.Methods One hundred fifty pailents scheduled to undergo 64-slice spiral CT coronary angiography were prospectively randomized into the following five groups with different injection protocols:group l:uniphasic injection without a flush;group 2:biphasic injection with a flush;group 3,group 4 and group 5:triphasic injection with a diluted contrast material with 3:7.5:5.7:3 contrast/saline ratio respectively.Attenuation was measured in the right atrium,right ventricle,left atrium,left ventricle,ascending aorta,fight coronary artery and left coronary artery and analyzed with single factor variance test(ANOVA).The quality the coronary artery images was evaluated and compared using person Chi-Square.Results The total contrast material vohme were (67.0±5.3)ml,(59.9±4.9)ml,(62.9±3.2)ml,(69.2 4±5.7)ml and(70.9 4-4.6)ml in five groups respectively(F=27.43,P<0.01).Image quali～scores of coronary arteries were significant different among five groups(X2=18.81,P<0.05).There were signiflcandy differences in artifacts of the superior vena cava among five groups(X2=31.44,P<0.01).The artifacts in the superior vena cava in group 1 was the most,and in group 2 was the least.The mean enhancement values of right and left coronary arteries in group 2 were significantly greater than those in other groups(F=2.47 and 4.10,P<0.05).The visualization of both left ventricle and right ventricle cavities W88 the best in group 3.Conclusion Biphasic injection and triphasic injection are better than uniphasic injection for 64-slice spiral CT coronary angiography and triphasic injecfion is better than biphasic injection for the visualization of both left ventricle and right ventricle cavities.