Noninvasive Angiography Of Coronary Artery With 16-slice Spiral Computed Tomography: Clinical Study

Background:With the development of living standard, coronary artery disease (CAD) has been the most frequent cause of morbidity and mortality. Conventional coronary angiography(CCA) is still the gold standard for the assessment of coronary artery disease.However, the technique is limited by its invasive characteristics and related complications. Since the majority of all diagnostic invasive coronary angiographics are not followed by therapeutic interventions, there is a growing interest in non-invasive technologies to visualize coronary artery tree and to diagnose CAD. Recently,with the development of CT technology and exploration of software,scan speed has been greatly increased. With the help of retrospectively ECG-gated technology,multi-slice spiral computed tomography(MSCT) coronary artery angiography has become a reality.As for the movement of the heart and the small and thin coronary artery, the time resolulion capacity and the spatial resolulion capacity of MSCT still have certain limitation. To get high quality images,a lot of studies about the influence of heart rate , breath ,cardiac arrhythmia,the reconstruction R-R phase have been completed.But there are few study about the infuence of vasodilator and contrast concentration on image quality. In this study , we try to investigate the influence of vasodilator isosorbide dinitrate and contrast medium concentration on image quality and evaluate the clinical value of 16-MSCT coronary angiography (16SCTCA) in coronary artery disease.Part one:Effects of sublingual isosorbide dinitrate on coronary lumen diameter and segments visualized on 16-MSCT coronary angiographyObjective To study the influence of sublingual isosorbide dinitrate on the coronary artery lumen diameter and segments visualized on 16-MSCT angiography.Methods Fifty patients were prospectively included in this study:25 were examined without isosorbide dinitrate(group A),and 25 were examined after the administration of sublingual isosorbide dinitrate(group B).CT angiography was performed using a 16-MSCT scanner.Two blinded obserbers quantitively assessed lumen diameter and counted the number of segments visualized and clinical side effects.Results The lumen diameters were significantly larger in group B than in group A.The number of segment 8,9,10,12,13,14 visualized in group B was significantly higher than in group A.No statistically significant difference in segment 1,2,3,4,5,6,7,11 between the two groups was shown and the number of side effects in the two groups was not significantly different.Conclusion Sublingual isosorbide dinitrate significantly dilates the coronary arteries and improve the image quality of MSCT coronary angiography without increasing the number of side effects.Part two:The influence of different concentration iodine contrast medium on image quality on 16-MSCT coronary angiographyObjective To investigate the effect of contrast medium concentration on 16-MSCT coronary angiography through comparing the image quality and segments visualized using Iobitridol (300 mg I/ml),Iohexol (350 mg I/ml) and Iopromide (370 mg I/ml). Methods Seventy-five patients were randomly divided into three groups, 16-MSCT coronary angiography were performed using different concentration iodine contrast medium Iobitridol (300 mg I/ml), Iohexol (350 mg I/ml) and Iopromide (370 mg I/ml) respectively.The contrast-enhanced value at the level of Aorta,PA,LV,RV,RCA,LM,LAD and LCX were measured and the number of segments visualized were counted.Results The contrast-enhanced value at the level of Aorta ,LV,RCA,LM,LAD and LCX were significantly higher in group B,C than in group A,there was statistical significance,but there was not statistically difference at RV.The number of segment 8,9,12,13,14 visualized in group B ,C was significantly higher than in group A.No statistically significant difference in segment 1,2,3,4,5,6,7,10,11 among the three groups was shown and the number of side effects in the three groups was not significantly different.Conclusion There are more segments visualized on 16-MSCT coronary angiography and better image quality using Iohexol and Iopromide,so Iohexol and Iopromide are more suitable for 16-MSCT coronary angiography.Part three:The degree of coronary artery stenosis:assessment of 16-MSCT coronary angiography and DSA and Kappa analysis of consistency of the two technologies in different coronary plaqueObjective To evaluate consistency of the 16-slice spiral computed tomography coronary angiography (16SCTCA) and the conventional coronary angiography(CCA) in estimating the degree of coronary stenoses caused by different coronary plaque. Methods The 16-slice spiral computed tomography coronary angiography and conventional coronary angiography of 38 patients with suspected coronary artery disease were analyzed. All coronary segments were divided into three groups according to the coronary plaque by MSCT(soft plaque,complicated plaque and calcified plaque) ,the stenosis degree of vessels were identified by the 16SCTCA and CCA respectively by four grades( no stenosis ,diameter reduction≤50%, 51%～75% and 76%～100%).The consistency of 16SCTCA and CCA in evaluating stenosis degree were scored by Kappa Analysis by three groups respectively(soft,complicated and calcified plaque). Results: Of the 38 cases, there were 439 normal,28 soft plaque,26 complicated plaque and 39 calcified plaque coronary segments respectively. The consistency coefficient Kappa Value in soft,complicated and calcified plaque group was 0.640,0.503 and 0.178 respectively.Conclusion: Compared with CCA, there were good quantitative and qualitative diagnostic ability of coronary stenosis in soft and complicated plaque group by 16SCTCA,but in calcified plaque group, the consistency of estimating the degree of stenosis between 16SCTCA and CCA is weak.