The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi' an Jiaotong University, Xi' an, PR China.
Ultrasonics. 2011 Dec;51(8):857-69. doi: 10.1016/j.ultras.2011.03.011. Epub 2011 Apr 7.
To monitor HIFU-induced lesion with elastography in quasi-real time, a fast correlation based elastographic algorithm using tissue stiffness-dependent displacement estimation (SdDE) is developed in this paper. The high time efficiency of the proposed method contributes to the reduction on both the number of the displacement points and the computational time of most of the points by utilizing local uniformity of the tissue under HIFU treatment. To obtain admirable comprehensive performance, the key algorithm parameter, a threshold to densify the displacement points, is optimized with simulation over a wedge-inclusion tissue model by compromising the axial resolution (AR) and the computational cost. With the optimum parameter, results from both simulations and phantom experiments show that the SdDE is faster in about one order of magnitude than the traditional correlation based algorithm. At the same time, other performance parameters, such as the signal-to-noise ratio (SNRe), the contrast-to-noise ratio (CNRe) and the axial resolution (AR), are superior to or comparable with that obtained from the traditional algorithm. In vitro experiments on bovine livers validate the improvement on the time efficiency under the circumstances of real tissue and real radio frequency (RF) signal. This preliminary work implies potential of the SdDE in dynamic or close real time guidance and monitoring of HIFU treatment.
为了在准实时条件下利用超声弹性成像监测高强度聚焦超声（HIFU）治疗所导致的组织损伤，本文提出了一种基于相关的快速弹性成像算法，该算法利用组织硬度相关的位移估计（SdDE）。由于 HIFU 治疗下组织的局部均匀性，该方法通过减少位移点的数量和大多数点的计算时间，实现了较高的时间效率。为了获得令人满意的综合性能，通过在楔形组织模型上进行仿真，利用一种权衡轴向分辨率（AR）和计算成本的方法，对关键算法参数——用于对位移点进行加密的阈值进行了优化。利用优化后的参数，仿真和离体实验结果均表明，SdDE 的速度比传统的相关算法快约一个数量级。同时，SdDE 的其他性能参数（如信噪比（SNRe）、对比噪声比（CNRe）和轴向分辨率（AR））优于或与传统算法相当。牛肝的离体实验验证了在真实组织和真实射频（RF）信号条件下，时间效率的提高。这项初步工作表明 SdDE 具有在 HIFU 治疗中进行动态或接近实时引导和监测的潜力。
