Effect Of 640-slice CT Multiple-phase Reconstruction On Improving Coronary Image Quality

ObjectiveBy comparing the quality of coronary image before and after multiple-phase reconstruction,to investigate the influence of heart rate and beat on coronary image quality,and the improvement of coronary quality by different heart rate segments.MethodsNinety-two patients with CTCA imaging were selected from the outpatient department of our hospital.The auto-best phase reconstruction image could not meet the diagnostic requirements,but the multiple-phase reconstruction could meet the diagnostic.According to the number of beats automatically generated by the machine,they were divided into two groups,Beat1 group and Beat2group;According to the fluctuation range of heart rate(HR),they were divided into three groups: HR≤70,HR 71-80,and HR≥81.The diagnostic consistency between the two physicians was analyzed by Kappa.The K-S method was used to test the normality of the basic data.Comparison of before and after reconstruction image excellent and good rates between groups of beat using R*C list chi-square test.The difference of quality score before and after image reconstruction was calculated by using symbol rank test in heart rate group.The linear trend chi-square test was used to calculate the change trend of diagnostic rate before reconstruction.After reconstruction,the diagnostic quantity was compared by chi-square test with multiple sample rates.ResultsThe mean heart rate of all groups was skewed and the difference was statistically significant,all P<0.05.The Kappa values before and after reconstruction were 0.830 and 0.853 respectively,> 0.75.The evaluation consistency was excellent.The excellent and good rate before and after image reconstruction in beat group was statistically significant,P<0.05,showed that the image quality improved after reconstruction.Before and after all coronary segment reconstruction in HR71-80 group,P<0.05,It shows that the image quality is improved after reconstruction;HR ≤ 70,HR ≥ 81 groups before and after reconstruction of the image difference was statistically significant,All P<0.05,It shows that the image quality is improved after reconstruction;There was no significant difference in OM2 images between HR≤70 and HR≥81groups,P>0.05,The change of image quality is not obvious.There was no significant difference in diagnostic rate between the three groups before reconstruction,P>0.05,That is,the diagnostic rate of the three groups of images did not change obviously with the change of heart rate.There was a statistically significant difference in diagnostic rates between the three groups,P<0.05,That is,there is a difference between the diagnostic rates in the three groups.There was no statistical difference between HR ≤ 70 and HR71-80 group,P>0.017,There is no difference in diagnostic rate between the two groups;The other two were statistically different,P<0.017,That is,the diagnostic rate of the two pairs of images is different.ConclusionsThe heart rate in CTCA examination should be less than 80 beats/min.The effect of coronary image is good.The effect of multiple-phase reconstruction to improve the quality of coronary image is remarkable,and the reconstructed image can provide more valuable help for clinic.