基于希氏变换的超声基频算法估计骨小梁间距

摘要

Ultrasonic backscatter signal is quite sensitive to the microstructure of cancellous bone.Tra-becular bone spacing (TbSp)is an important parameter for characterizing bone microstructures.In order to acquire TbSp accurately from the ultrasonic backscatter signal of the cancellous bone,a TbSp estima-tion method is proposed using a combination of the Hilbert transform and fundamental frequency estima-tion (HFE)method.The HFE results from the cancellous bone in vitro are compared with the TbSp ob-tained fromμ-CT.The HFE results are accurate (estimation error<3%)and stable (standard variation<4%)at higher frequencies (5 MHz and 10 MHz),and more accurate when standard TbSp is large,and have a high correlation (r 2 =0.75—0.99,p <0.01 ,n=1 6)with the standard TbSp at different frequen-cies.It shows that the HFE method is accurate and stable for TbSp estimation.The HFE method is ver-tified to characterize the cancellous bone TbSp.%超声背散射信号对松质骨的微观结构极其敏感。骨小梁间距(Trabecular bone spacing,TbSp)是用于表征松质骨微结构的一个重要参数。为了能从松质骨超声背散射信号中准确获得松质骨 TbSp,本文提出了一种希尔伯特变换和基频估计法相结合的 TbSp 估计算法。将该算法应用于离体松质骨的超声背散射信号,获得相应的 TbSp 值,并与显微 CT 测得的 TbSp 进行比较。结果表明,HFE 算法在信号频率较高时(5 MHz 和10 MHz),估计结果更准确(误差<3%)且稳定(标准偏差<4%)；TbSp 较大时,估计结果更为准确；TbSp 的估计值与标准值在不同频率下均有显著的相关性(r 2=0.75~0.99, p <0.01,n=16)。HFE 算法估计 TbSp 具有准确性和稳定性,可用来表征松质骨 TbSp。