Elen An, Choi Hon Fai, Loeckx Dirk, Gao Hang, Claus Piet, Suetens Paul, Maes Frederik, D'hooge Jan
Department of Electrical Engineering, Medical Image Computing, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
IEEE Trans Med Imaging. 2008 Nov;27(11):1580-91. doi: 10.1109/TMI.2008.2004420.
Current ultrasound methods for measuring myocardial strain are often limited to measurements in one or two dimensions. Cardiac motion and deformation however are truly 3-D. With the introduction of matrix transducer technology, 3-D ultrasound imaging of the heart has become feasible but suffers from low temporal and spatial resolution, making 3-D strain estimation challenging. In this paper, it is shown that automatic intensity-based spatio-temporal elastic registration of currently available 3-D volumetric ultrasound data sets can be used to measure the full 3-D strain tensor. The method was validated using simulated 3-D ultrasound data sets of the left ventricle (LV). Three types of data sets were simulated: a normal and symmetric LV with different heart rates, a more realistic asymmetric normal LV and an infarcted LV. The absolute error in the estimated displacement was between 0.47 +/-0.23 and 1.00 +/-0.59 mm, depending on heart rate and amount of background noise. The absolute error on the estimated strain was 9%-21% for the radial strain and 1%-4% for the longitudinal and circumferential strains. No large differences were found between the different types of data sets. The shape of the strain curves was estimated properly and the position of the infarcts could be identified correctly. Preliminary results on clinical data taken in vivo from three healthy volunteers and one patient with an apical aneurism confirmed these findings in a qualitative manner as the strain curves obtained with the proposed method have an amplitude and shape similar to what could be expected.
当前用于测量心肌应变的超声方法通常仅限于一维或二维测量。然而，心脏运动和变形实际上是三维的。随着矩阵换能器技术的引入，心脏的三维超声成像已变得可行，但存在时间和空间分辨率低的问题，这使得三维应变估计具有挑战性。本文表明，基于强度的自动时空弹性配准可用于处理当前可用的三维容积超声数据集，以测量完整的三维应变张量。该方法使用左心室（LV）的模拟三维超声数据集进行了验证。模拟了三种类型的数据集：具有不同心率的正常对称左心室、更逼真的不对称正常左心室和梗死左心室。估计位移的绝对误差在0.47±0.23至1.00±0.59毫米之间，具体取决于心率和背景噪声量。估计应变的绝对误差，径向应变为9%-21%，纵向和周向应变为1%-4%。不同类型的数据集之间未发现大的差异。应变曲线的形状估计正确，梗死部位能够被正确识别。对三名健康志愿者和一名患有心尖动脉瘤患者的体内临床数据的初步结果，以定性方式证实了这些发现，因为用所提出的方法获得的应变曲线的幅度和形状与预期相似。
