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Ultrasonic backscatter characterization of cancellous bone using a general Nakagami statistical model

Chinese Physics B 2019年第2期28卷 313-320页

作者： Chengcheng Liu Rui Dong Boyi Li Ying Li Feng Xu Dean Ta Weiqi Wang Institute of Acoustics School of Physics Science and EngineeringTongji University Department of Electronic Engineering Fudan University State Key Laboratory of ASIC and System Fudan University

The goal of this study is to analyze the statistics of the backscatter signal from bovine cancellous bone using a Nakagami model and to evaluate the feasibility of Nakagami-model parameters for cancellous bone characterization. Ultrasonic backscatter measurements were performed on 24 bovine cancellous bone specimens in vitro and the backscatter signals were compensated for the frequency-dependent attenuation prior to the envelope detection. The statistics of the backscatter envelope were modeled using the Nakagami distribution. Our results reveal that the backscatter envelope mainly followed pre-Rayleigh distributions, and the deviations of the backscatter envelope from Rayleigh distribution decreased with increasing bone density. The Nakagami shape parameter(i.e., m) was significantly correlated with bone densities(R = 0.78–0.81, p < 0.001) and trabecular microstructures(|R| = 0.46–0.78, p < 0.05). The scale parameter(i.e.,?) and signal-to-noise ratio(SNR) also yielded significant correlations with bone density and structural features. Multiple linear regressions showed that bone volume fraction(BV/TV) was the main predictor of the Nakagami parameters,and microstructure produced significantly independent contribution to the prediction of Nakagami distribution parameters,explaining an additional 10.2% of the variance at most. The in vitro study showed that statistical parameters derived with Nakagami model might be useful for cancellous bone characterization, and statistical analysis has potential for ultrasonic backscatter bone evaluation.

关键词： ultrasonic backscatter cancellous bone statistical analysis Nakagami model

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The spectrum entropy estimation method for ultrasonic backscattering signal in cancellous bones

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Chinese Journal of Acoustics 2017年第3期36卷 337-346页

作者： XU Feng XU Yiwen LIU Chengcheng TA De'an GUO Jianzhong Department of Electronic Engineering Fudan UniversityShanghai 200433 Institute of Acoustics Tongji UniversityShanghai 200092 Shanghai Key Laboratory of Medical Image Processing and Computer Assisted Surgery Fudan UniversityShanghai 200433 School of Physics Shaanxi Normal UniversityXi'an 710119

In the application of cancellous bone ultrasound diagnosis based on backscattering method, it is of great importance to estimate fast and accurately whether the valid backscattering signal exists in the received signal. We propose a fast estimation method based on spectrum entropy method. With 984 records of adult calcaneus clinical data, we estimate the validity of the backscatter signal using this method. The results of the proposed method and the results of experience-base judgement were compared and analyzed. And two key parameters, the signal range length and the segment number of the spectrum entropy, were analyzed. The results show when the signal range length is 13 I^s and the segment number is 15 20, this method can get the best result （accuracy〉95%, sensitivity〉99%, specificity〉87%）, while taking little calculation time （1.5 ms）. Therefore, this spectrum entropy method can satisfy the accuracy and real-time requirements in the ultrasonic estimation for cancellous bone.

关键词： bone The spectrum entropy estimation method for ultrasonic backscattering signal in cancellous bones

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长骨中振动声激发超声导波的方法

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物理学报 2017年第15期66卷 169-176页

作者：刘珍黎宋亮华白亮许凯亮他得安复旦大学电子工程系上海200433 复旦大学科技处上海200433 法国郎之万实验室巴黎75012

为了实现一定频段内任意低频下在长骨中激励导波信号,本文提出一种采用聚焦高频(5 MHz)超声换能器在长骨皮质骨中激发低频(150 kHz)超声导波的振动声方法.首先介绍了板状超声导波理论和双声束共聚焦法与单声束调幅法激发振动声的基本原... 详细信息

为了实现一定频段内任意低频下在长骨中激励导波信号,本文提出一种采用聚焦高频(5 MHz)超声换能器在长骨皮质骨中激发低频(150 kHz)超声导波的振动声方法.首先介绍了板状超声导波理论和双声束共聚焦法与单声束调幅法激发振动声的基本原理;进而采用三维有限元仿真方法分析振动声激发低频超声导波的基本现象,然后结合牛胫骨板离体实验,验证振动声激发低频超声导波的可行性.结果均表明,双声束共焦与单声束振动超声均可在骨板中激发低频超声导波.相关研究方法有助于提高空间域长骨中超声导波测量精度,以及在一定频段内实现任意频率激励等,对发展低频超声导波在体测量长骨皮质骨的新技术具有一定的指导意义.

关键词：长骨皮质骨超声导波有限元仿真振动声激发

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Estimating mean trabecular bone spacing based on the combination of Hilbert transform and fundamental frequency estimation

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Science Foundation in China 2017年第3期25卷 57-71页

作者：李颖徐峰刘成成许凯亮他得安王威琪 Department of Electronic Engineering Fudan UniversityShanghai 200433China Institute of Acoustics Tongji UniversityShanghai 200092China Sorbonne Université UPMC Univ Paris 06INSERM UMR-S 1146CNRS UMR 7371Laboratoired'ImagerieBiomédicaleF-75006ParisFrance State Key Laboratory of ASIC and System Fudan UniversityShanghai 200433China Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention(MICCAI)of Shanghai Shanghai 200032China

Ultrasonic backscatter signals from cancellous bone are sensitive to the microstructure of trabecular bone,and thus enable the feasibility to extract microstructural information of trabecular *** mean trabecular bone spacing(MTBS)is an important parameter for characterizing bone *** paper proposes an MTBS estimation method based on the combination of Hilbert transform and fundamental frequency estimation(CHF). The CHF was verified with ultrasonic backscatter signals from simulations and in vitro measurements at a central frequency of *** CHF method was compared with the simplified inverse filter tracking(SIFT)method,Simons' Quadratic Transformation(QT)method,Singular Spectrum Analysis(SSA)method,and Spectral Autocorrelation(SAC)***-Carlo simulations were performed by varying the MTBS,signal-to-noise ratio(SNR),standard deviation of regular spacing(SDRS),amplitude ratio of diffuse scattering to regular scattering(Ad)and frequency dependent attenuation(nBUA).The simulation results showed that the CHF method had a better performance in MTBS estimation under almost all the examination conditions except for *** estimation percentage correct(EPC)was greater than 90% when the MTBS was in the range of 0.4to *** the in vitro measurements,the estimated EPC by the CHF method was91.25±7.81%(mean±standard deviation).A significant correlation was observed for the CHF-estimated MTBS and micro-computed tomography(μ-CT)-measured values(R^2=0.75,p<0.01).These results demonstrate that the CHF method is anti-interference for MTBS estimation and can be used to estimate trabecular bone spacing.

关键词： Ultrasonic backscatter Mean trabecular bone spacing estimation Hilbert transform and fundamental frequency estimation Cancellous bone microstructure

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超声背散射骨质评价中的频散衰减测量与补偿

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物理学报 2019年第18期68卷 144-151页

作者：东蕊刘成成蔡勋兵邵留磊李博艺他得安同济大学物理科学与工程学院声学研究所上海200092 复旦大学电子工程系上海200433

超声背散射法已逐渐应用于骨质的评价与诊断.相比于人体软组织,致密多孔的骨组织中超声衰减大,导致接收到的超声信号微弱,频散失真严重.骨组织的超声频散衰减通常由超声透射法测量.然而,透射法测量的超声衰减为传播路径上组织介质衰减... 详细信息

超声背散射法已逐渐应用于骨质的评价与诊断.相比于人体软组织,致密多孔的骨组织中超声衰减大,导致接收到的超声信号微弱,频散失真严重.骨组织的超声频散衰减通常由超声透射法测量.然而,透射法测量的超声衰减为传播路径上组织介质衰减的平均值,无法区分软组织、皮质骨及松质骨的衰减效应,无法测量感兴趣区域内松质骨组织的超声衰减.本文旨在研究松质骨超声频散衰减的背散射测量方法,分析补偿超声背散射信号频散失真的可行性.离体测量16块松质骨样本的超声背散射与透射信号(中心频率1 MHz).采用四种背散射方法(谱移法、谱差法、谱对数差法和混合法)测量松质骨超声频散衰减系数,与超声透射法测量的频散衰减标准值进行对比.结果表明,骨样本超声频散衰减范围为2.3—6.2 dB/mm/MHz,透射法测量的超声频散衰减(均值±方差)为(4.14±1.14) dB/mm/MHz;谱移法、谱差法、谱对数差法和混合法测量的频散衰减(均值±方差)分别为(3.88±1.15) dB/mm/MHz,(4.00±0.98) dB/mm/MHz,(3.77±0.84)dB/mm/MHz,(4.05±0.85) dB/mm/MHz.背散射法测量的频散衰减系数与标准值有较高的相关性(R=0.78—0.92, p <0.01),其中,谱差法(R=0.91, p <0.01)和混合法(R=0.92, p <0.01)测量结果更准确(相对误差小于20%).以上结果说明背散射法测量松质骨超声频散衰减具有可行性,基于傅里叶变换-逆变换原理可以补偿背散射信号频散衰减失真,显著提高信号强度,有利于后续超声背散射骨质评价及成像研究.

关键词：超声背散射骨质评价频散衰减衰减补偿

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Diagnosis of osteoporosis based on multi-scale wavelet parameters of ultrasonic guided waves

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Chinese Journal of Acoustics 2017年第4期36卷 429-438页

作者： SONG Xiaojun TA De'an MOILANEN Petro Department of Electronic Science and Technology Shanghai University of Electric Power Department of Electronic Engineering Fudan University Shanghai key Laboratory of Medical Image Processing and Computer Assisted Surgery Fudan University Department of Physics Jyvaskyla University

Evaluating bone regularly is important to prevent and control the disease of osteoporosis. Impact of osteoporosis on ultrasonic guided waves propagating in human long bones is studied in this paper. Multi-scale wavelet transform is proposed to process the received guided waves, and by analyzing energy changes in detail components of high order wavelet at different propagating distance to assess if osteoporosis happened. The guided waves signals are collected from the tibias of 13 volunteers. Based on the analysis of multi-scale wavelet transform, the high order detail components d6 and d5 changed dramatically with the propagation of ultrasonic guided waves along long bones, which means these 7 volunteers are diagnosed with osteoporosis. Compared with X-ray diagnosis, the effectiveness of this method can reach 92.3% in 13 volunteers. This suggests the multi-scale wavelet transform method is potential in ultrasonic assessment of bone quality.

关键词： osteoporosis wavelet guided ultrasonic bones dramatically regularly propagating transducer cortical

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有限元法仿真LIPUS照射骨细胞的局部声场分布

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声学技术 2017年第6期36卷 549-555页

作者：蒋文杰孙舒心徐峥他得安复旦大学电子工程系上海200433 同济大学声学研究所上海200092

低强度脉冲超声(Low-Intensity Pulsed Ultrasound,LIPUS)作为一种可用于治疗骨病的潜在物理疗法,可以有效避免药物的不良反应,且具有无创伤、无电离辐射等优点,因而有着广阔的应用前景。应用有限元法(Finite Element Method,FEM)仿真研... 详细信息

低强度脉冲超声(Low-Intensity Pulsed Ultrasound,LIPUS)作为一种可用于治疗骨病的潜在物理疗法,可以有效避免药物的不良反应,且具有无创伤、无电离辐射等优点,因而有着广阔的应用前景。应用有限元法(Finite Element Method,FEM)仿真研究LIPUS照射骨细胞时的局部声场分布,从微观角度探究骨细胞与声场间的相互作用以及各超声参数和照射位置对于声场分布的影响。首先建立了骨细胞模型,然后在不同位置施加超声激励并改变超声的激励声压与频率,计算不同情况下的声场分布,最后对仿真结果进行综合分析与比较。结果表明,骨细胞会在一定程度上影响声场的分布,且超声的各个参数及照射位置均对声场有一定的影响。仿真结果从声压与能量的角度阐述了LIPUS治疗骨病的潜在物理机制,另一方面也为离体细胞实验中LIPUS的参数筛选和照射方式提供理论参考。

关键词：低强度脉冲超声有限元法骨细胞声场分布仿真

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高分辨率超声Lamb波频散曲线测量与板厚估计

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数据采集与处理 2017年第2期32卷 286-292页

作者：许凯亮张正罡刘丹他得安胡波巴黎第六大学法国国家科学研究院国家卫生与医学研究院生物医学成像实验室(LIB) 法国巴黎75006 复旦大学电子工程系上海200433 上海市医学图像处理与计算机辅助手术重点实验室上海200032

超声Lamb波在工业无损检测与评价中具有广阔的应用前景。但受制于超声导波多模式频散与混叠的影响,如何实现高分辨率超声导波的模式分离与频散曲线提取,进而定量分析材料的健康状况一直是研究的热点与难点。本文旨在将现代信号处理中广... 详细信息

超声Lamb波在工业无损检测与评价中具有广阔的应用前景。但受制于超声导波多模式频散与混叠的影响,如何实现高分辨率超声导波的模式分离与频散曲线提取,进而定量分析材料的健康状况一直是研究的热点与难点。本文旨在将现代信号处理中广泛采用的谱估计技术应用于超声Lamb波阵列信号分析,并通过提取频散曲线定量测量板厚度。以经典参数谱估计法中的Yule-Walker法与Burg法为例,实验测量和分析了3mm,4mm和5mm厚铝板中的宽带多模式Lamb波信号,准确地提取了铝板中的宽带Lamb波频散曲线,并比较了两种经典谱估计方法与二维傅氏变换法的性能,最终实现了铝板厚度估计。

关键词：超声Lamb波经典谱估计法频散曲线厚度估计无损检测

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松质骨超声背散射信号的谱信息熵判断方法

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声学学报 2016年第3期41卷 281-286页

作者：徐峰许怿文刘成成他得安复旦大学电子工程系上海200433 复旦大学上海市医学图像处理与计算机辅助手术重点实验室上海200032

在松质骨超声背散射评价的实际应用中,如何快速准确地判断接收到的信号中是否包含有效背散射信号是一个重要问题。提出一种基于谱信息熵的背散射信号判断方法。对在体采集的984例成人跟骨处临床数据,采用该方法判断背散射信号的有效性,... 详细信息

在松质骨超声背散射评价的实际应用中,如何快速准确地判断接收到的信号中是否包含有效背散射信号是一个重要问题。提出一种基于谱信息熵的背散射信号判断方法。对在体采集的984例成人跟骨处临床数据,采用该方法判断背散射信号的有效性,将判断结果与经验判断结果进行对照分析,并分析该方法中的信号区间长度和谱信息熵分段数对判断结果的影响。结果表明,当信号区间长度为13μs,谱信息熵分段数为15~20时,该方法可以获得最佳的判断结果（准确度〉95%,灵敏度〉99%,特异度〉87%）,并且计算时间极短（1.5 ms）。因此采用谱信息熵方法判断背散射信号的有效性,可以满足超声骨质评价中对准确性和实时性的要求。

关键词：散射信号判断结果骨超声分段数松质区间长度背散射系数对照分析超声探头骨质吸收

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High-resolution bone microstructure imaging based on ultrasonic frequency-domain full-waveform inversion

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Chinese Physics B 2021年第1期30卷 295-310页

作者： Yifang Li Qinzhen Shi Ying Li Xiaojun Song Chengcheng Liu Dean Ta Weiqi Wang Department of Electronic Engineering Fudan UniversityShanghaiChina Human Phenome Institute Fudan UniversityShanghaiChina Academy for Engineering and Technology Fudan UniversityShanghaiChina

The main challenge in bone ultrasound imaging is the large acoustic impedance contrast and sound velocity differences between the bone and surrounding soft tissue. It is difficult for conventional pulse-echo modalities to give accurate ultrasound images for irregular bone boundaries and microstructures using uniform sound velocity assumption rather than getting a prior knowledge of sound speed. To overcome these limitations, this paper proposed a frequency-domain fullwaveform inversion(FDFWI) algorithm for bone quantitative imaging utilizing ultrasonic computed tomography(USCT).The forward model was calculated in the frequency domain by solving the full-wave equation. The inverse problem was solved iteratively from low to high discrete frequency components via minimizing a cost function between the modeled and measured data. A quasi-Newton method called the limited-memory Broyden–Fletcher–Goldfarb–Shanno algorithm(L-BFGS) was utilized in the optimization process. Then, bone images were obtained based on the estimation of the velocity and density. The performance of the proposed method was verified by numerical examples, from tubular bone phantom to single distal fibula model, and finally with a distal tibia-fibula pair model. Compared with the high-resolution peripheral quantitative computed tomography(HR-p QCT), the proposed FDFWI can also clearly and accurately presented the wavelength scaled pores and trabeculae in bone images. The results proved that the FDFWI is capable of reconstructing high-resolution ultrasound bone images with sub-millimeter resolution. The parametric bone images may have the potential for the diagnosis of bone disease.

关键词： quantitative imaging full-waveform inversion bone microstructure ultrasonic computed tomography high resolution

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