The role of dual source CT in the evaluation of aortic mechanical valves / 中华放射学杂志

ABSTRACT

Objective To study the value of dual-source CT(DSCT)in assessing aortic mechanical valve with 3D cardiovascular imaging technique.Methods Thirty-four patients with mechanical aortic valve transplantation were enrolled.Nineteen cases transplanted with On-x valve and 15 cases with St jude valre.CT scan was performed in all 34 patients and MRI scan in 30 patients.The CT imaging quality of On-x valve with St jude valve was compared by two independent samples Wilcoxon rank test.Two independent sampies test was used to compare tlle valve angle in the two kinds of valve and also in the same group.The relative functional index of left ventricle in CT and MR analysis by paired-samples t Test. Results The image quality was dirided into three grades.Six hundred and eighty phases in all 34 patients.which included 391 phases with grade 1,171 phases with grade 2 and 118 phases with grade 3.There were no significant different between two kinds of mechanical valve in image quality(image quality of grade 1Z=-1.084,P=0.286;grade 2Z=-0.088,P=0.945;grad 3Z=-1.045,P=0.319).The mean bileaflet angle of 34 cases was 82.0°±4.4°in completely opening and 34.5°±5.7°in completely closing.The mean radian gradient over openess and closure was 47.5°±7.5°.The radian gradient of St iude group(55.0°±1.8°)was obviously larger than On-x group(41.5°±4.1°)(t=-11.732,P=0.000).But,there were no significant difference between dual-source CT and 1.5 T MR when evaluate the left ventrical fuction,including EF[MR.EF(57.2-1-2.8)%,CT-EF(57.9±2.8)%,f-0.496,P=0.623],EDV[MR-EDV (121.6±9.1)ml,CT-EDV(132.9±11.2)ml,t=-1.198,P0.240],ESV[MR-ESV(55.1±6.9)ml,CT-ESV(59.5±7.6)ml,t=-1.094,P=0.283],myocardium mass at ED[MR-Myo.mass (155.5 ±12.6)g,CT-Myo.mass(147.9±11.6)g,t=1.823,P=0.079]and CO[MR-CO(5.7±0.4)ml/min,CT-CO(5.9±0.5)ml/min,t=-3.211,P=0.775].Conclusions Dual source CT with 3D cardiovascular imaging technique is valuable and effective for evaluating aortic mechanical valve.The shape of the whole valve and movement of bileaflet reappears well.With the postprocessing software,it allows evaluating aortic mechanical valve function,reliable measurements of opening and closing leaflet angles and left ventrieal function.