摘要
为建立与计算机图像分析技术相结合的人体二尖瓣狭窄下游湍流剪应力 (Turbulent shear stree,TSS)多普勒超声定量检测方法。本研究采用多普勒超声技术对正常人和不同程度二尖瓣狭窄病人组的二尖瓣下游血流速度频谱等指标进行多位点记录 ,通过计算机图像分析技术 ,测算出相关位点 TSS大小。结果表明不同程度二尖瓣狭窄组的二尖瓣下游核心位点 TSS与相对扰动强度 (Relative turbulent intensity,Irel)始终低于边界各位点 ;边界位点 TSS、Irel和流场均匀性等指标在正常对照和不同程度狭窄组之间均存在显著性差异 (P<0 .0 5 ) ,并均与有效瓣口面积 (Effective orifice area,EOA)明显相关。结论为二尖瓣有效开口面积越小 ,狭窄越重 ,射流边界 TSS和 Irel越大 ,射流核心区 TSS明显低于边界。研究结果显示 :应用与计算机图像分析相结合的多普勒超声技术所测人体二尖瓣狭窄下游 TSS与流场均匀性等常规多普勒超声指标具有良好的相关性 ,能共同反映不同狭窄程度病人瓣区血流动力学变化 ,因此表明本方法能比较准确地刻画人体二尖瓣狭窄下游 TSS的大小 ,并且 ,还具有安全无创、抗干扰能力强的特点 ,可用于瓣膜病病人瓣区流场中 TSS的定量分析。
In order to establish a method for measuring quantitatively turbulent shear stress(TSS) downstream of mitral stenosis in vivo based on Doppler echocardiography and computer aided image analysis, we used doppler echocardiography to record the spectrum of flow velocity downstream of mitral valve at several locations in normal persons and in patients with mitral stenosis. With the computer aided analysis of spectrum images, the magnitude of TSS was measured at the locations. The results demonstrate that no matter how severe the mitral stenosis is, the TSS and relative turbulent intensity(I rel ) at the central locations of jet are lower than those at the marginal ones. A significnt difference in the quantitative items of TSS, I rel and flow field uniformity between normal persons and patients with varying degree of mitral stenosis was noticed( P<0.05) . There was a significant correlation between these items and effective orifice area (EOA), and we found that the smaller EOA is, the more severe the extent of stenosis is and the greater the magnitude of both TSS and I rel are, and that the highest magnitude of TSS is focused on the marginal area of jet. These results indicate that there is an obvious correlation between TSS(measured by Doppler echocardiography combined with computer aided image analysis) and flow field uniformity. They can coincidently reveal the hemodynamic changes resulting from mitral stenosis of varied severeness, implying that our method could exactly depict the magnitude of TSS downstream of mitral stenosis in vivo and is non invasive and good for anti disturbance. The method can be used to analyze quantitatitvely TSS in the flow field of heart valve in patients with valvular diseases.
出处
《生物医学工程学杂志》
EI
CAS
CSCD
2002年第1期71-75,88,共6页
Journal of Biomedical Engineering
基金
国家自然科学基金资助项目 ( 39770 2 0 5 )
国家教委博士点基金资助项目 ( C995 4)
关键词
二尖瓣狭窄
湍流剪应力
多普勒超声
方法学
Mitral stenosis Turbulent shear stress Doppler echocardiography Methodology
