Rojo-Alvarez José Luis, Bermejo Javier, Rodríguez-González Ana Belén, Martínez-Fernández Andrés, Yotti Raquel, García-Fernández Miguel A, Carlos Antoranz José
Department of Signal Theory and Communications, Universidad Rey Juan Carlos, Madrid, Spain.
Med Image Anal. 2007 Dec;11(6):513-25. doi: 10.1016/j.media.2007.04.004. Epub 2007 Apr 25.
Quantitative processing of color-Doppler echocardiographic images has substantially improved noninvasive assessment of cardiac physiology. Many indices are computed from the velocity fields derived either from color-Doppler tissue imaging (DTI), such as acceleration, strain and strain-rate, or from blood-flow color-Doppler, such as intracardiac pressure gradients (ICPG). All of these indices are dependent on the finite resolution of the ultrasound scanner. Therefore, we developed an image-dependent method for assessing the influence of temporal, spatial, and velocity resolutions, on cardiovascular parameters derived from velocity images. In order to focus our study on the spatial, temporal, and velocity resolutions of the digital image, we did not consider the effect of other sources of noise such as the interaction between ultrasound and tissue. A simple first-order Taylor's expansion was used to establish the functional relationship between the acquired image velocity and the calculated cardiac index. Resolutions were studied on: (a) myocardial acceleration, strain, and strain-rate from DTI, and (b) ICPG from blood-flow color-Doppler. The performance of Taylor's-based error bounds (TBEB) was demonstrated on simulated models and illustrated on clinical images. Velocity and temporal resolution were highly relevant for the accuracy of DTI-derived parameters and ICPGs. TBEB allow to assess the effects of ideal digital image resolution on quantitative cardiovascular indices derived from velocity measurements obtained by cardiac imaging techniques.
彩色多普勒超声心动图图像的定量处理极大地改善了心脏生理学的无创评估。许多指标是根据从彩色多普勒组织成像（DTI）得出的速度场计算得出的，如加速度、应变和应变率，或者从血流彩色多普勒得出的，如心内压力梯度（ICPG）。所有这些指标都依赖于超声扫描仪的有限分辨率。因此，我们开发了一种依赖图像的方法，用于评估时间、空间和速度分辨率对从速度图像得出的心血管参数的影响。为了将我们的研究重点放在数字图像的空间、时间和速度分辨率上，我们没有考虑其他噪声源的影响，如超声与组织之间的相互作用。使用简单的一阶泰勒展开式来建立采集到的图像速度与计算出的心脏指数之间的函数关系。研究了以下方面的分辨率：（a）DTI得出的心肌加速度、应变和应变率，以及（b）血流彩色多普勒得出的ICPG。基于泰勒的误差界限（TBEB）的性能在模拟模型上得到了验证，并在临床图像上进行了说明。速度和时间分辨率与DTI得出的参数和ICPG的准确性高度相关。TBEB允许评估理想数字图像分辨率对通过心脏成像技术获得的速度测量得出的定量心血管指标的影响。
