CT Evaluation Of Myocardial Intensity At The First Pass Of Iodine Contrast Agent In Patients With Stenosis Of Coronary Artery

Objective:To measure the myocardial CT density of the corresponding blood supply zone in three normal or mild stenosis patients under coronary computed tomography angiography(CCTA),and to evaluate the degree of myocardial enhancement during the first passage of iodine contrast;For patients with single coronary artery stenosis above severe,measure the CT density of the corresponding blood supply area for severe coronary artery stenosis,sub occlusion and occlusion,preliminary evaluation of the iodine contrast agent for the first time through the degree of myocardial enhancement between the three differences.Methods:A retrospective analysis of 524 patients undergoing coronary artery computed tomography(CCTA)and catheter coronary angiography from January 2012 to August 2016 for suspected coronary heart disease in our hospital.Male 365 cases,female 159 cases,aged 28 to 92(65.82 ± 8.96)years old.The interval between the two examinations was 1 to 25(6.32 ± 4.11)days.Among the 524 patients,catheterized coronary angiography showed 76 patients(normal group)with normal or mild stenosis(<50%);catheter coronary angiography showed a single coronary artery over severe stenosis(?75%)(the remaining two coronary arteries were normal or mild stenosis),including 148 patients with severe coronary artery stenosis,146 patients with coronary artery occlusion,and 148 patients with coronary artery occlusion.Using the second generation dual source CT for CCTA inspection,rack rotation time:0.28 s/r;detector collimation:2×64 ×0.6 mm,Z axis fly focus technology acquisition:2×128×0.6 mm;tube voltage:120kV?140kV,tube current:330mAs?400mAs;reconstruction time resolution:75ms;layer thickness:0.75mm,layer spacing:0.7mm;display field:250?270mm;matrix:512 × 512;image reconstruction algorithm:Backlog(FBP),the reconstructed convolution kernel of the image reconstruction:B26f;Retrograde ECG-giral spiral mode or prospective ECG triggering according to the patient's own condition Prospective-ECG triggered sequential scan mode.(18 mg)was placed in the middle of the elbow,and 50 to 60 ml of the counter-iodohydrin(300 mg/ml)was injected through the trocar at a flow rate of 5 to 6 ml/s,followed by the same The concentration of 0.9%saline was 30?50 ml,and the region of interest(ROI)was set up on the level of tracheal bifurcation in the ascending aorta by using iodine contrast agent tracer.The triggering threshold was>100HU,after reaching the threshold delay 6S automatically start the heart scan.The best cross-sectional CT images of the best reconstructed phase were selected and used for image post-processing to evaluate the extent of coronary artery stenosis and measure left ventricular density.The CCTA images were analyzed by using the multiple planar reformation(MPR)technique to obtain the horizontal short axis of the vertical left major axis based on the left ventricular long axis.According to the American Heart Association(AHA),the left ventricular myocardium was divided into 17 segments of the myocardium and the"bovine eye diagram" was drawn.The mean value of the myocardial segment was measured three times.The CT densities and correction values of the left ventricular segments of the patients with normal or mild stenosis and single coronary artery severe above the stenosis were measured and calculated respectively.Statistical analysis was performed to analyze the normal or mild the degree of CT density and the correction value of the left ventricular myocardium when the iodine contrast agent was first passed in the patients with normal or mild stenosis and coronary artery severe above the stenosis.To initial analyze the characteristics of the left ventricle myocardial CT density.while iodine contrast agent was first passed in patients with normal or mild stenosis and over severe stenosisResults:?The mean CT density and the corrected values of the left ventricle myocardial of the three normal coronary arteries were:the apex(96.24 ± 0.57)HU and(0.304 ? 0.003)HU,the mid(96.81±0.41)HU and(0.313±0.002),the basal(97.19±0.27)HU and(0.327±0.002).There had significant between the apex segment and the middle and basal segments(P<0.05).There was no significant difference between the middle segment and the basal segment(P>0.05).The mean CT density and the corrected values of the three coronary arteries were:the left coronary artery(96.71 ±3.67)HU and(0.322±0.012),the left circumflex artery(96.58±3.84)HU and(0.322±0.009),the right coronary artery(96.63±4.01)HU and(0.322±0.010),and the mean CT density and corrected value of the three coronary arteries had no statistically significant(P>0.05).? Comparison of CT density and correction value of three coronary arteries with single coronary artery with severe above the stenosis:The mean CT density of left ventricular myocardium and the correction valuehere had statistically significant(P<0.05)between lesion branch and non-lesion branch in the same group.Comparison of CT density and correction value of left ventricular myocardium in patients with single coronary artery and severe stenosis:The CT density of left ventricular myocardium and the corrected values had significant(P<0.05)between the severe stenosis group and the occlusion group and the occlusion group(P<0.05),but there was no significant difference between the occlusion group and the occlusion group(P>0.05).Conclusion:1)The CT density of the left ventricular myocardium measured on the CT image of CCTA and representing the degree of myocardial enhancement can indirectly indicate the myocardial perfusion of iodine contrast agent for the first time.2)There was no significant difference in CT density between the three normal or mild stenosis coronary.In patients with narrow coronary artery stenosis,the degree of stenosis is heavier,the lower the CT density of the corresponding blood supply area,suggesting that iodine contrast agent for the first time through the myocardial perfusion less.