Study On Dynamism Of The Aortic Annulus During Cardiac Cycle With MSCT

Objective:To explore the dynamism of the aortic annulus(AA)during cardiac cycle and its correlation with calcification with MSCT.Methods:A total of 69 aortic stenosis patients(AS group)and 69controls(normal control group)underwent retrospective ECG-gated CT.Dimensions of AA were assessed on both systolic and diastolic phases.For each phase,the long diameter,short diameter,area,perimeter of AA were measured,respectively.The features of annular dimention change and the relationship with calcium score were analyzed.Finally,the differences of dynamic of AA in different calcification grades were compared.Results:The mean annular dimensions were significantly larger during systole than diastole(all P<0.001),whereas ellipticity index(EI)was significantly larger during diastole than systole in both group(P<0.001).There was no significant difference in the diameters of AA between the two groups during systole(P>0.05).In AS group,the perimeter-derived diameter(D_P)of AA was significantly larger than area-derived diameter(D_A)in both systolic and diastolic phase(t=14.439、15.649,P<0.001).The relative change rate of AA area was significantly higher than perimeter(t=13.917,P<0.001)during cardiac cycle,as well as the relative change rate of D_A was significantly higher than D_P(t=4.790,P<0.001).There were weak negative correlation between the calcium score of AA and the change of long dimension,short dimension,average dimension,D_A and D_p(r=-0.278、-0.239、-0.251、-0.264、-0.302,all P<0.05)。Furthermore,the dynamic of AA had significant difference among different calcification grades(all P<0.05).Conclusions:The morphology and structure of AA significantly changed during cardiac cycle in both AS and control group,the mean annular dimensions are significantly larger during systole than diastole,there is no obvious expansion of AA in AS group compared with control group.The dynamism of AA is related to calcification,and the dynamic change of AA withseverecalcification significantly reduced.Systolic multiparameter measurement can provide accurate anatomical data for transcatheter aortic valve replacement.