Diluted Contrast Material For Noninvasive 64-row Multi-detector Computed Tomography COronary Angiography And Assessment Of Left Ventricular Function

Objectives This study was designed to determine the optimal contrast protocols for 64-row multi-detector computed tomography coronary angiography. To assess the value of left ventricular function compared with Echocardiography.Methods Sixty patients scheduled to undergo retrospectively electrocardiographically gated 64-row multi-detector computed tomographic coronary angiography. These patients were prospectively randomized into the following three groups to accept different contrast injection portocol:group A:biphasic protocol with a flush; group B,C:biphasic protocols with a diluted contrast material which was made of 30%: 70%and50 %: 50% contrast/saline ratio respectively. Attenuation was measured in right coronary artery,left coronary artery, anterior descending branch and convolution branch, and rate the uniformity of the right heart, the visualization of the coronary artery,the wall of left ventricle independently. The best protocol group in which diluted contrast material and group A were studied with echocardiography. Twenty series of images were reconstructed at every 5% throughout the cardiaccycle. From the reconstructed cardic planes CT images(left ventricle short axle, left ventricular long-axis and four-chamber view), quantitative information on ventricular volume changes throughout the cardiaccycle can be derived. The appropriate reconstruction windows for the systolic and diastolic phases are visually identified as the images showing the minimum and maximum ventricular diameter. Diastolic and systolic left ventricular volumes were measured using circulation software of 64-row multi-detector CT. Diastolic and systolic left ventricular volumes can be calculated using standard software for distance and area measurements. Echocardiography was performed using PHILIPS iE33 by two chief ultrasound experts using M-Mode Color Doppler. Statistical Analysis:paired t test,Pearson's correlation coefficient and Linear regression analysis were performed to determine the correlationnd limits of agreement for the LV end-diastolic nd end-systolic volumes, stroke volume,and ejection fraction between CT and echocardiograpResult1.Right coronary artery,left coronary artery and convolution branch were no significant difference(P>0.05).2.Anterior descending branch is significant differencebetween groups(P<0.05).3.The uniformity of the right heart and the visualization of the coronary artery were no significant difference(P >0.05).4.The wall of left ventricle independently is significant difference between groups(P<0.05). Group A and B;Group A and C;Group B and C are significant difference between groups(P<0.05).5.On the left ventricular function,z=3.225>1.96 P<0.05, The correlation coefficient is significant differencebetween groups.Group B's correlation is more than Group A.Conclusion1.For 64-row multi-detector computed tomography coronary angiography and assessment of left ventricular function, The best protocol is group B in which diluted contrast material was made of 30%: 70%.2. Diluted contrast material for 64-row multi-detector computed tomography coronary angiography is noninvasive assessment of the coronary tree, whereas the analysis of left ventricular parameters provides additional information of cardiac function without further radiation exposure.Compare with echocardiography, left ventricular function indexes tests by 64-row multi-detector computed tomography and diluted contrast material were accurate, the correlation of the results was quite well.