Study Of Coronary Artery Plaque By MSCT In Asymptomatic Patients With Type 2 Diabetes

Objective:using 16-slice spiral computed tomography(16-SCT) and calibration phantom images to assess the coronary atherosclerosis state and coronary plaque types in asymptomatic patients with type 2 diabetes mellitus(DM),and analyze the plaque that containing calcium parameters and the constituent ratio of each segment segmented by CT value,study development and progress of the plaques,it would be benefit most for further studies. Materials and Methods:Acceptance of CT coronary angiography in 285 successive participants,after excluding 130 subjects because of artifacts and absence of phantom, we identified 155 subjects.The subjects were divided into two groups,51 with DM (30 men,21 women;mean age,56.61±10.38 years)and 104 non-DM(60 men,44 women;mean age,58.64±11.00).Overall study we used smartscore sequence by prospectively ECG-triggered 16-SCT and the calibration phantom for measuring bone density(GE)and coronary computed tomography angiography.we determined the amount of plaques,the calcium concentration(CC),mean CT value,Agatston score(AS),volume score(VS),calcified volume(CV),and mineral mass(MM) of each individual calcified plaque in each subject.Additionally,we segmented each plaque that containing calcium by CT value and obtained the constituent ratio of each segment,the segment standard was 130～199HU,200～299HU,300～399HU and≥400HU.We performed Spearman rank correlation test to analyze the relevance between two variables and performed rank test to analyze differential significance.A value of P≤0.05 was considered to indicate statistical significance for all tests.Results:1) The difference of plaque constituent ratio between asymptomatic type2 DM group and control group is significant(P<0.05).And the incidence of the former's noncalcific plaque and calcific plaque is higher than control group(P=0.040,0.027),however,the incidence of mixed plaque is lower compared to(P=0.000) control group.2) There is no statistically differences in the two groups of subjects about the individual parameters of calcified plaque and CT segmentation constitution(P>0.05), and these four sets of measurements which was divided in accordance with blood sugar level also showed no statistically significant difference(P>0.05).3) High positive correlations could be found between CC,CV,MM,AS and VS in all subjects,The correlation coefficients were 0.729～0.982,and all of the P values are 0.000.4)The values of CC,CV,MM,AS and VS were increased with the increasing of FPG.5) In DM group,the constituent rate of calcified plaque between male and female show no statistically significant(p=0.95);the constituent rate of individual calcified plaque in the >55 age group is higher than <55 age group(p=0.030).6) The distribution frequency of individual calcified plaques in coronary artery branches is in descending turn of LAD(left anterior descending coronary artery), RCA(right coronary artery),LCx(left circumflex coronary artery),LM(Left coronary artery main stem),Diagonal and PDA(posterior descending coronary artery) in DM group.7) In DM group,both the individual parameters of calcified plaque and CT segmentation constitution showed no statistically significant difference in the age and gender(p> 0.05).8) In DM group,The proportion of 130～199HU and≥400HU was higher than 200～299HUand300～399HU(p<0.05),but there is no significantly different between in 130～199HU and≥400HU,200～299HUand 300～399HU(p>0.05).Conclusion:This study is the first to report the plaque that containing calcium parameters and the constituent ratio of each segment segmented by CT value,the results reflected the progression of coronary artery plaque to some extent,it would benefit most from further evaluation for further study.