定量组织速度及应变率成像评价犬不同程度心肌缺血的实验研究

Different degree of myocardial ischemia in dogs assessed by quantitative tissue velocity imaging and strain rate imaging

目的评价定量组织速度(QTVI)及应变率成像(SRI)对冠脉狭窄的诊断价值。方法11只开胸犬结扎左冠状动脉前降支(LAD)建立心肌缺血模型。分别于基础状态、缺血状态(LAD狭窄50%,75%,100%)。采集连续3个心动周期的组织速度图,用QTVI及SRI软件分析左室各节段纵轴方向上收缩期QTVI及SRI曲线的变化。结果非LAD节段:缺血状态下各项指标较基础状态无显著改变。LAD节段:与基础状态比较,LAD狭窄50%时收缩期峰值速度(Vs)略有减少,但无统计学意义(P>0.05),而心尖段收缩期峰值应变率(SRpeak)显著减少或矛盾运动(P<0.05)。LAD狭窄75%时Vs及SRpeak明显减少,差异有显著意义。LAD狭窄100%时,SRpeak几乎接近基线水平。结论QTVI及SRI可以作为定量评价心肌缺血导致的心肌局部功能异常的方法。

Objective To investigate the value of stenosis of coronary artery using quantitative tissue velocity imaging （QTVI） and strain rate imaging （SRI）. Methods Left anterior descending coronary artery （LAD） were ligated 11 experimental dogs, three complete cardiac cycles were stored in cineloop format of tissue velocity imaging at before, 50%, 75 %, 100% stenosis of LAD, off-line regional strain rate and systolic velocity along long axis using digital workstation were obtained and analyzed the features of curves. Results non-LAD segment： no significant differences were found between before and after LAD ligation. LAD segment： the peak systolic velocities （Vs） was slightly decreased, but have no significant difference in 50% stenosis of LAD （P〉0. 05）, the peak strain rate （SRpeak） in apical segment was significantly decreased （P^0. 05）. Vs and SRpeak was decreased obviously in 75% stenosis of LAD comparing with baseline state. SRpeak was almost like baseline during 100% stenosis of LAD. Conclusion QTVI and SRI may be a promising new tool for the quantification of ischemia-induced regional myocardial dysfunction.