Laboratoire d'Imagerie Paramétrique, UPMC Univ Paris 06, CNRS UMR 7623, ESPCI ParisTech, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
Laboratoire d'Imagerie Paramétrique, UPMC Univ Paris 06, CNRS UMR 7623, 15 rue de l'Ecole de Médecine, 75006 Paris, France.
Ultrasonics. 2014 Jul;54(5):1197-202. doi: 10.1016/j.ultras.2013.06.004. Epub 2013 Jun 25.
The development of novel quantitative ultrasound (QUS) techniques to measure the hip is critically dependent on the possibility to simulate the ultrasound propagation. One specificity of hip QUS is that ultrasounds propagate through a large thickness of soft tissue, which can be modeled by a homogeneous fluid in a first approach. Finite difference time domain (FDTD) algorithms have been widely used to simulate QUS measurements but they are not adapted to simulate ultrasonic propagation over long distances in homogeneous media. In this paper, an hybrid numerical method is presented to simulate hip QUS measurements. A two-dimensional FDTD simulation in the vicinity of the bone is coupled to the semi-analytic calculation of the Rayleigh integral to compute the wave propagation between the probe and the bone. The method is used to simulate a setup dedicated to the measurement of circumferential guided waves in the cortical compartment of the femoral neck. The proposed approach is validated by comparison with a full FDTD simulation and with an experiment on a bone phantom. For a realistic QUS configuration, the computation time is estimated to be sixty times less with the hybrid method than with a full FDTD approach.
开发新型定量超声（QUS）技术来测量髋关节，关键取决于模拟超声传播的可能性。髋关节 QUS 的一个特点是超声通过一大厚度的软组织传播，在最初的方法中，可以通过均匀的流体来建模。有限差分时域（FDTD）算法已被广泛用于模拟 QUS 测量，但它们不适合模拟在均匀介质中长距离的超声波传播。本文提出了一种混合数值方法来模拟髋关节 QUS 测量。在骨骼附近进行二维 FDTD 模拟，并与瑞利积分的半解析计算相结合，以计算探头和骨骼之间的波传播。该方法用于模拟专门用于测量股骨颈皮质腔中环向导波的设置。通过与全 FDTD 模拟和骨体模实验进行比较，验证了所提出的方法。对于现实的 QUS 配置，与全 FDTD 方法相比，混合方法的计算时间估计减少了六十倍。
