双源螺旋CT对非缺血性二尖瓣反流机制的研究

目的运用双源螺旋CT（DSCT）探寻非缺血性二尖瓣反流的反流机制。方法超声诊断为二尖瓣反流并行CT俭查的46例患者．其中男性28例，女性18例；年龄37～81岁，平均年龄63．57岁。二尖瓣反流组依据多普勒超声检查分为轻度反流组（20例）、中度反流组（14例）、重度反流组（12例）。分别在cT图像上测量收缩中期幕状面积、幕状高度、二尖瓣瓣环前后径、联合间距离等二尖瓣装置形态参数。另随机选择无二尖瓣反流的体检者43例作为止常埘照组．．结果小同程度二尖瓣反流组在幕状面积、幕状高度、瓣环前后径、收缩中期和舒张末期瓣环面积较正常对照组差异有统计学意义（P〈O．05）。而瓣环联合间径差异无统计学意义（P〉0．05）。不同程度二尖瓣反流组在舒张期左心室短轴长度、球形度．收缩期左心室长径、舒张末期容积（EDV）、收缩末期容积（ESV）差异有统计学意义（P〈0．05），、乳头肌间距变化度、左心事长径位移度组间差异均无统计学意义（P〉0．05）。结论DSCT功能检查对二尖瓣反流机制研究有重要价值，、非缺血性二尖瓣反流乃因心室-瓣膜环受过重前负荷而扩张．导致前外侧乳头肌腱索对前叶体部的过度牵拉．致使精确闭合的双侧瓣叶产毕前叶的云云h不对称导计对合而稠的减少，产生反流。

Mechanism of non-ischemic mitral regurgitation assessed by dual-source spiral CT

Objective To investigate the mechanism of non-ischemic mitral valve regurgitation with dual-source spiral CT （DSCT）. Methods A total of 46 patients with mitral regurgitation （MR） diagnosed by two-dimensional echocardiograpby underwent DSCT coronary angiography and confirmed non-ischemic were enrolled, included 28 males and 18 females, aged 37 81 years old with a mean age of 63.57. MR were divided into mile group（n= 20）, moderate group（n = 14）, ant severe group（n = 12） as determined by echocardiography. The 43 controls were randomly selected from the cases without MR or other cardiac diseases. Mitral apparatus morphological parameters included mid-systolic tenting area, tenting height, anteroposterior （A -P） diameter and intercommisural（C-C） diameter of mitral annulus and left ventricle（LV） parameters were evaluated by DSCT, Results Tenting area, tenting height, A-P diameter of annulus and mid-systolic/end-diastolic annulus area showed significantly differences between MR groups and control group（P 〈 0.05） while C-C diameter of annulus had no statistical significance （P 〉 0.05）. LV end- diastolic short-axis length, sphericity index, end-diastolic volume（EDV） and end-systolic volume（ESV） were significantly different（P 〈 0.05） in different MR groups. The distance between heads of papillary muscles （PM） and LV long-axis length had no statistical significance between MR groups. Conclusion It is demonstrated that DSCT examination of mechanisms have an important value in MR, the non-ischemic mitral regurgitation is caused by enlargement of the LV chamber and mitral annulus due to increased preload than the asymmetrical subvalvular PM motion with LV. Anterior leaflet tethering produced by displacing anteriorlaterial PM attached to enlarged LV, and led to preserved or excessive mitral valve motion.