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Joint spectrogram segmentation and ridge-extraction method for separating multimodal guided waves in long bones

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Science China(Physics,Mechanics & Astronomy) 2013年第7期56卷 1317-1323页

作者： ZHANG ZhengGang XU KaiLiang ta dean WANG WeiQi Department of Electronic Engineering Fudan University

Ultrasonic guided waves (GWs) can be used to evaluate long bones effectively because of the ability to provide the information of the whole bone. In this study, a joint spectrogram segmentation and ridge-extraction (JSSRE) method was proposed to separate multiple modes in long bones. First, the Gabor time-frequency transform was applied to obtain the spectrogram of multimodal signals. Then, a multi-class image segmentation algorithm was used to find the corresponding region of each mode in the spectrogram, including an improved watershed transform and a region growing procedure. Finally, the ridges were extracted and the time domain signals representing individual modes were reconstructed from these ridges in each region. The validations of this method were discussed by simulated multimodal signals with different signal-to-noise ratios (SNR). The correlation coefficients between the original signals without noise and the reconstructed signals were calculated to analyze the results quantitatively. The results showed that the extracted ridges were in good agreement with generated theoretical dispersion curves, and the reconstructed signals were highly related to the original signals, even under the SNR=3 dB situation.

关键词： multimodal guided waves long bone spectrogram segmentation

Three-dimensional ultrasound subwavelength arbitrary focusing with broadband sparse metalens

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Science China(Physics,Mechanics & Astronomy) 2022年第2期65卷 50-56页

作者： Xue Jiang JiaJie He ChuanXin Zhang HuaLiang Zhao WeiQi Wang dean ta Cheng-Wei Qiu Center for Biomedical Engineering School of Information Science and TechnologyFudan UniversityShanghai 200433China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore

Ultrasound focusing in three-dimensional(3 D)space is of crucial and enduring significance in a variety of biomedical and industrial *** ultrasound focusing based on active phase array or passive geometry of bulky size is unable to realize the 3 D arbitrary focusing with subwavelength *** metamaterial of complex deep-subwavelength microstructure has facilitated the advanced airborne-sound-focusing but is inevitably not applicable for underwater ultrasound,restricted by the law between the multi-modes coupling/thermal viscosity and the feature size of the ***,we aim to circumvent the restriction by increasing the feature size of the metamaterial while keeping the compact overall geometry,and realize the robust subwavelength ultrasound focusing with the sparse metalens of the wavelength-scale *** theoretically propose and demonstrate numerically and experimentally the broadband arbitrary ultrasound focusing in 3 D *** axial and off-axis ultrasound focusing with the subwavelength resolution(FWHMtalens within one-octave *** advantages of 3 D freewheeling focusing,subwavelength resolution,spatial sparsity,geometric simplicity,and broadband,the sparse metalens would offer more initiatives to advanced researches in ultrasound focusing and empower applications such as precise biomedical imaging and therapy,nondestructive evaluation,integrated and multiplexed ultrasound devices.

关键词： broadband ultrasound focusing sparse metalens subwavelength resolution three-dimensional focusing

An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates

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Engineering 2015年第3期1卷 336-343页

作者： Chengcheng Liu Rong Zhang Ying Li Feng Xu dean ta Weiqi Wang Department of Electronic Engineering Fudan University Department of Neonatology Children’s Hospital of Fudan University Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai

Ultrasonic backscatter technique has shown promise as a noninvasive cancellous bone assessment tool. A novel ultrasonic backscatter bone diagnostic （UBBD） instrument and an in vivo application for neonatal bone evaluation are introduced in this study. The UBBD provides several advantages, including noninvasiveness, non- ionizing radiation, portability, and simplicity. In this study, the backscatter signal could be measured within 5 s using the UBBD. Ultrasonic backscatter measurements were performed on 467 neonates （268 males and 199 females） at the left calcaneus. The backscatter signal was measured at a central frequency of 3.5 MHz. The delay （-/-1） and duration （7-2） of the backscatter signal of interest （SOl） were varied, and the apparent integrated backscatter （AIB）, frequency slope of apparent backscatter （FSAB）, zero frequency intercept of apparent backscatter （FIAB）, and spectral centroid shift （SCS） were calculated. The results showed that the SOl selection had a direct influence on cancellous bone evaluation. The AIB and FIAB were positively correlated with the gestational age （｜R｜ up to 0.45, P 〈 0.001） when -/-1 was short （〈 8 μS）, while negative correlations （｜R｜ up to 0.56, P 〈 0.001） were commonly observed for T1 〉 10 IJS. Moderate positive correlations （IRI up to 0.45, P 〈 0.001） were observed for FSAB and SCS with gestational age when 71 was long （〉 10 μs）. The 7-2 mainly introduced fluctuations in the observed correlation coefficients. The moderate correlations observed with UBBD demonstrate the feasibility of using the backscatter signal to evaluate neonatal bone status. This study also proposes an explicit standard for in vivo SOl selection and neonatal cancellous bone assessment.

关键词： ultrasonic backscatter cancellous bone evaluation signal of interest (SOI) backscatter instrument neonatal bone status

Virtual Fluorescence Translation for Biological Tissue by Conditional Generative Adversarial Network

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Phenomics 2023年第4期3卷 408-420页

作者： Xin Liu Boyi Li Chengcheng Liu dean ta Academy for Engineering and Technology Fudan UniversityShanghai 200433China State Key Laboratory of Medical Neurobiology Fudan UniversityShanghai 200433China Center for Biomedical Engineering Fudan UniversityShanghai 200433China

Fluorescence labeling and imaging provide an opportunity to observe the structure of biological tissues,playing a crucial role in the field of ***,when labeling and imaging biological tissues,there are still some challenges,e.g.,time-consuming tissue preparation steps,expensive reagents,and signal bias due to *** overcome these limitations,we present a deep-learning-based method for fluorescence translation of tissue sections,which is achieved by conditional generative adversarial network(cGAN).Experimental results from mouse kidney tissues demonstrate that the proposed method can predict the other types of fluorescence images from one raw fluorescence image,and implement the virtual multi-label fluorescent staining by merging the generated different fluorescence images as ***,this proposed method can also effectively reduce the time-consuming and laborious preparation in imaging processes,and further saves the cost and time.

关键词： Virtual fluorescence labeling Image translation Tissues section Generative adversarial network

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

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

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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 tatistical 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

Application of a supervised machine learning algorithm in bone evaluation using ultrasonic backscatter signal

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Chinese Journal of Acoustics 2020年第3期39卷 399-410页

作者： DIWU Qiangqiang LIU Chengcheng LI Ying LI Boyi XU Feng ta dean Department of Electronic Engineering Fudan UniversityShanghai 200433 Academy for Engineering and Technology Fudan UniversityShanghai 200433

Improving the diagnosis accuracy is essential for the clinical application of osteoporosis evaluation using ultrasonic backscatter *** vitro ultrasonic backscatter signals were measured on bone specimens and backscatter parameters were *** the measured backscatter parameters,the involved cancellous bone specimens were evaluated and classified using support vector machine and adaptive boosting *** showed that the accuracy of classification was 80.00%-82.86% and the specificity of osteoporosis diagnosis was significant(specificity>92.3%).The supervised machine learning method using ultrasonic backscatter in bone evaluation is effective in the diagnosis of *** performance of the proposed machine-learning method is superior to the traditional bone evaluation using quantitative backscatter *** study may contribute to the application of ultrasonic backscatter in the diagnosis of osteoporosis in vivo.

关键词： diagnosis specificity osteoporosis

Experimental realization of fractal fretwork metasurface for sound anomalous modulation

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Chinese Physics B 2024年第5期33卷 473-478页

作者：何佳杰于书萌江雪他得安 Department of Biomedical Engineering School of Information Science and TechnologyFudan UniversityShanghai 200433China Academy for Engineering and Technology Fudan UniversityShanghai 200433China

Natural creatures and ancient cultures are full of potential sources to provide inspiration for applied *** by the fractal geometry in nature and the fretwork frame in ancient culture,here we design the acoustic metasurface to realize sound anomalous modulation,which manifests itself as an incident-dependent propagation behavior:sound wave propagating in the forward direction is allowed to transmit with high efficiency while in the backward direction is obviously *** quantitatively investigate the dependences of asymmetric transmission on the propagation direction,incident angle and operating frequency by calculating sound transmittance and energy *** compact fractal fretwork metasurface for acoustic anomalous modulation would promote the development of integrated acoustic devices and expand versatile applications in acoustic communication and information encryption.

关键词： acoustic metasurface fractal geometry sound anomalous modulation

Deep learning method for cell count from transmitted-light microscope

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Journal of Innovative Optical Health Sciences 2023年第5期16卷 115-127页

作者： Mengyang Lu Wei Shi Zhengfen Jiang Boyi Li dean ta Xin Liu Fudan University Academy for Engineering and Technology ShanghaiP.R.China Tianjin Center for Medical Device Evaluation and Inspection Tianjin P.R.China Shanghai University School of Communication&Information Engineering Shanghai P.R.China Fudan University Center for Biomedical Engineering Shanghai P.R.China Fudan University State Key Laboratory of Medical Neurobiology Institutes of Brain Science ShanghaiP.R.China

Automatic cell counting provides an effective tool for medical research and ***,cell counting can be completed by transmitted-light microscope,however,it requires expert knowledge and the counting accuracy which is unsatisfied for overlapped ***,the image-translation-based detection method has been proposed and the potential has been shown to accomplish cell counting from transmitted-light microscope,automatically and *** this work,a new deep-learning(DL)-based two-stage detection method(cGAN-YOLO)is designed to further enhance the performance of cell counting,which is achieved by combining a DL-based fluorescent image translation model and a DL-based cell detection *** various results show that cGAN-YOLO can effectively detect and count some different types of cells from the acquired transmitted-light microscope *** with the previously reported YOLO-based one-stage detection method,high recognition accuracy(RA)is achieved by the cGAN-YOLO method,with an improvement of 29.80%.Furthermore,we can also observe that cGAN-YOLO obtains an improvement of 12.11%in RA compared with the previously reported image-translation-based detection *** a word,cGAN-YOLO makes it possible to implement cell counting directly from the experimental acquired transmitted-light microscopy images with high flexibility and performance,which extends the applicability in clinical research.

关键词： Automatic cell counting transmitted-light microscope deep-learning fluorescent image translation.