多普勒组织成像研究左室壁节段性运动速度──应用新型的左心室模型体外试验

In vitro validation of tissue Doppler imaging of left ventricular regional wall velocities using a novel balloon phantom

目的 应用自制的左室模型研究组织多普勒成像 (TDI)测定左室壁节段性运动速度的可靠性和准确性。方法 自制一个左室模型来验证TDI的准确性。该模型以双层气球制作 ,连接一脉冲流量泵 ,分设 8种泵出量 (5 0～ 85ml/每搏 )。将模型浸入水槽后 ,以摄像机与TDI同时记录球壁的运动位移和速度。采用GE系统 5超声诊断仪 ,探头频率 5MHz。结果 M型与二维图像显示气球模型形状和壁运动与左心室十分相似。由TDI测得的球壁运动距离与摄像机同步测量距离相关密切 [前壁 :r =0 .97,sx =0 .2 4mm ,平均差±s =(0 .0 4± 0 .2 4)mm ;后壁r =0 .95 ,sx =0 .2 2mm ,平均差±s =(0 .0 3± 0 .2 4)mm]。球壁特定测量点的TDI运动速度亦与摄像所得结果相关密切 [前壁 :r =0 .97,sx =0 .30mm ,平均差±s =- (0 .0 4+0 .2 8)mm ;后壁 :r =0 .97,sx =0 .30mm ,平均差±s =(0 .0 4+0 .2 8)mm]。结论 球体模型提供了一种检测TDI准确性的新方法 ,证明所用TDI系统在测量壁运动距离和速度方面是准确可靠的。

Objective To investigate the validity and accuracy of tissue Doppler imaging (TDI) using a novel balloon phantom.Methods A new TDI validation method was used with a specially developed left ventricular balloon model mounted in a water bath and constructed using two pear shaped balloons. It was connected to a pulsatile flow pump at 8 stroke volumes (50～85 ml / beat ). The displacement and velocity of the balloon walls were recorded simultaneously by video imaging and TDI on a GE Vingmed System 5 with a 5 MHz phased array probe at the highest frame rates available.Results Conventional M mode and 2D imaging verified that the balloon model was similar to left ventricle in its shape and wall motion. There was good correlation and agreement between the maximum video excursion of the anterior and posterior walls of the phantom and results of the temporal integration of digital distance data by TDI [Anterior wall:r= 0.97 ,s x = 0.24 mm, mean difference±s=( 0.04 ± 0.24 )mm;Posterior wall:r= 0.95 ,s x = 0.22 mm,mean difference±s=( 0.03 ± 0.24 )mm].Analysis of the velocity profile by TDI method showed the velocity at each measured point correlated well with the velocity obtained from the video images [Anterior wall:r= 0.97 ,s x = 0.30 mm, mean difference±s=-( 0.04 ± 0.28 )mm;Posterior wall:r= 0.97 ,s x = 0.30 mm, mean difference±s=( 0.04 ± 0.28 )mm ].Conclusions The balloon model provides a new independent method for the validation of TDI data, it demonstrated that the present TDI system is reliable for measuring wall motion distance and velocity.