Huang Kai, Ta Dean, Wang Weiqi, Le L H
Dept. of Electron. Eng., Fudan Univ., Shanghai.
IEEE Trans Ultrason Ferroelectr Freq Control. 2008 Jul;55(7):1453-64. doi: 10.1109/TUFFC.2008.820.
Ultrasonic backscatter signals provide useful information relevant to bone tissue characterization. Trabecular bone microstructures have been considered as quasi-periodic tissues with a collection of regular and diffuse scatterers. This paper investigates the potential of a novel technique using a simplified inverse filter tracking (SIFT) algorithm to estimate mean trabecular bone spacing (MTBS) from ultrasonic backscatter signals. In contrast to other frequency-based methods, the SIFT algorithm is a time-based method and utilizes the amplitude and phase information of backscatter echoes, thus retaining the advantages of both the autocorrelation and the cepstral analysis techniques. The SIFT algorithm was applied to backscatter signals from simulations, phantoms, and bovine trabeculae in vitro. The estimated MTBS results were compared with those of the autoregressive (AR) cepstrum and quadratic transformation (QT) . The SIFT estimates are better than the AR cepstrum estimates and are comparable with the QT values. The study demonstrates that the SIFT algorithm has the potential to be a reliable and robust method for the estimation of MTBS in the presence of a small signal-to-noise ratio, a large spacing variation between regular scatterers, and a large scattering strength ratio of diffuse scatterers to regular ones.
超声背散射信号提供了与骨组织特征相关的有用信息。松质骨微观结构被视为具有规则和漫散射体集合的准周期性组织。本文研究了一种使用简化逆滤波器跟踪（SIFT）算法从超声背散射信号估计平均松质骨间距（MTBS）的新技术的潜力。与其他基于频率的方法不同，SIFT算法是一种基于时间的方法，它利用背散射回波的幅度和相位信息，从而保留了自相关和倒谱分析技术的优点。SIFT算法被应用于模拟、体模和体外牛松质骨的背散射信号。将估计的MTBS结果与自回归（AR）倒谱和二次变换（QT）的结果进行了比较。SIFT估计优于AR倒谱估计，并且与QT值相当。该研究表明，在存在小信噪比、规则散射体之间的大间距变化以及漫散射体与规则散射体的大散射强度比的情况下，SIFT算法有可能成为一种可靠且稳健的MTBS估计方法。
