AIM： To study the relation between acoustic parameters and histological structure of biological tissue and to provide the basis for high-resolution image of biological tissues and quantitative ultrasonic diagnosis of...AIM： To study the relation between acoustic parameters and histological structure of biological tissue and to provide the basis for high-resolution image of biological tissues and quantitative ultrasonic diagnosis of liver disease. METHODS： Ultrasonic imaging and tissue characterization of four normal porcine liver and five cirrhotic liver tissue samples were performed using a high frequency imaging system. RESULTS： The acoustic parameters of cirrhotic liver tissue were larger than those of normal liver tissue. The sound velocity was 1577 m/s in normal liver tissue and 1631 m/s in cirrhotic liver tissue. At 35 MHz, the attenuation coefficient was 3.0 dB/mm in normal liver tissue and 4.1 dB/mm in cirrhotic liver tissue. The backscatter coefficient was 0.00431 dB/Srmm in cirrhotic liver tissue and 0.00303 dB/Srmm in normal liver tissue. The backscatter coefficient increased with the frequency. The high frequency images coincided with their histological features. CONCLUSION： The acoustic parameters, especially the sound backscatter coefficient, are sensitive to the changes of liver tissues and can be used to differentiate between the normal and pathological liver tissues. High frequency image system is a useful device for highresolution image and tissue characterization.展开更多
Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGS). PVA and chitosan were also blended with colla...Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGS). PVA and chitosan were also blended with collagen. The physical and chemical properties of the matrices were characterized by SEM, DSC, and ESCA. L929 cells were implanted on the matrices to show the cytotoxic and the biological characters of the materials. The results indicate that EDC is an effective and non-cytotoxic cross-link reagent, which can replace the common dialdehyde reagent. The attachment of CS can improve the stability of collagen and accelerate cell growth. The addition of PVA can prepare porous matrices with smaller bore size. There are reactions between the chitosan and collagen, and the composite has good biological character. The presence of chitosan can also increase the amount of incorporated CS.展开更多
The importance of ligaments in providing joint stability and the incidence of injuries, dictates a need to increase their structural and mechanical properties understanding. Additionally, one of the challenges in the ...The importance of ligaments in providing joint stability and the incidence of injuries, dictates a need to increase their structural and mechanical properties understanding. Additionally, one of the challenges in the orthopedic industry is to design TKA （total knee arthroplasty） aiming to be soft-tissues friendly. This requires a priori knowledge of physiological knee function, in which the passive stability is achieved and guaranteed by the complex envelope of soft tissues around the joint. Therefore, the knowledge of the mechanical behavior of knee ligaments is fundamental. For this reason, our study aims to define and apply in a pilot study, an ad-hoc methodology to mechanically characterize ligaments of native human knees. The cruciate and collateral ligaments from a fresh frozen cadaver leg were accurately harvested. Each ligament was independently tested during a tensile test at different strain rates, simulating different deformation speeds during gait. Moreover, additional tensile tests until failure were also performed. Axial force and deformation were continuously recorded during each test. Results show that each ligament exhibited own typical non-linear, speed-related behavior. High repeatability in the results is observed among the different repeated tests confirming the robustness of the used methodology. This information will be helpful for clinicians, engineers and researchers to improve the biomechanical knowledge about knee, to develop better implants and to be able to improve the currently available numerical models of the human knee.展开更多
Elasticity is an important physical property of human tissues. There is a tremendous difference in elasticity between normal and pathological tissues. Noninvasive evaluation of the elasticity of human tissues would be...Elasticity is an important physical property of human tissues. There is a tremendous difference in elasticity between normal and pathological tissues. Noninvasive evaluation of the elasticity of human tissues would be valuable for clinical practice. Magnetic resonance elastography(MRE)is a recently developed noninvasive imaging technique that can directly visualize and quantitatively measure tissue elasticity. This article reviewed the MRE technique and its current status.展开更多
With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real...With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real-time processing,and non-invasive imaging.In this review,one group of OCE techniques,namely dynamic OCE,are introduced and discussed including external dynamic OCE mapping and imaging of ex vivo breast tumor,external dynamic OCE measurement of in vivo human skin,and internal dynamic OCE including acoustomotive OCE and magnetomotive OCE.These techniques overcame some of the major drawbacks of traditional static OCE,and broadened the OCE application fields.Driven by scientific needs to engineer new quantitative methods that utilize the high micron-scale resolution achievable with optics,results of biomechanical properties were obtained from biological tissues.The results suggest potential diagnostic and therapeutic clinical applications.Results from these studies also help our understanding of the relationship between biomechanical variations and functional tissue changes in biological systems.展开更多
The quality of ultrasound scanning images is usually damaged by speckle noise.This paper proposes a method based on local statistics extracted from a histogram to reduce ultrasound speckle through a region growing alg...The quality of ultrasound scanning images is usually damaged by speckle noise.This paper proposes a method based on local statistics extracted from a histogram to reduce ultrasound speckle through a region growing algorithm.Unlike single statistical moment-based speckle reduction algorithms,this method adaptively smooths the speckle regions while preserving the margin and tissue structure to achieve high detectability.The criterion of a speckle region is defined by the similarity value obtained by matching the histogram of the current processing window and the reference window derived from the speckle region in advance.Then,according to the similarity value and tissue characteristics,the entire image is divided into several levels of speckle-content regions,and adaptive smoothing is performed based on these classification characteristics and the corresponding window size determined by the proposed region growing technique.Tests conducted from phantoms and in vivo images have shown very promising results after a quantitative and qualitative comparison with existing work.展开更多
We have proposed an interferometric setup for biomedical analysis in transillumination modality.Wavelength dependence of optical properties must be considered for selecting source and sample.An expansion of the sampl...We have proposed an interferometric setup for biomedical analysis in transillumination modality.Wavelength dependence of optical properties must be considered for selecting source and sample.An expansion of the sample optical properties,around the central wavelength of emission,serves to account for spectral effects.Expected spectral values depend on the central moments of the source,and specific constants associated to the optical properties of the sample.By matching wavelength characteristics of source and sample,a first-order approximation is applicable.In such case,the expected values are exactly the optical properties evaluated at the central wavelength.Furthermore,in the first-order approximation,the transillumination interferometer yields the integrated attenuation of the sample at the central wavelength of emission.We verify the latter assertion by performing a wavelength-dependent Monte Carlo analysis to calculate the response of the transillumination interferometer.Recovered attenuation coefficients,for imaging and characterization scenarios,are in agreement with the value computed at the central wavelength of the source.展开更多
A high-speed digital acquisition and wide-band measurement system was used to acquiring and recording the ultrasonic pulse waveforms backscattered from normal and several pathological pig's fresh liver tissues (in...A high-speed digital acquisition and wide-band measurement system was used to acquiring and recording the ultrasonic pulse waveforms backscattered from normal and several pathological pig's fresh liver tissues (including ballooning degeneration, fatty degeneration, cirrhosis) in vitro. Some frequency-domain analyses were performed in which integrated backscattering coefficient (IBSC), frequency dependence of backscattering coefficient (FDBSC),and mean spacing (MS) among adjacent scatterers of the tissues were determined.In the experiments the frequency domain was from 3MHz to 7 MHz. The obtained results show that the differences among normal and various pathological tissues cause distinct changes of the measured parameters. The results show that the ultrasonic spectum technique, which can be used in tissue characterization for pathological liver in clinical, has an exciting prospect.展开更多
The proliferation of vascular smooth muscle cells (VSMC) plays a role in the maintenance of hypertension and atherosclerosis. Diadenosine polyphosphates have been identified as modulators of the cardiovascular system....The proliferation of vascular smooth muscle cells (VSMC) plays a role in the maintenance of hypertension and atherosclerosis. Diadenosine polyphosphates have been identified as modulators of the cardiovascular system. We detected the existence of diadenosine polyphosphates in the heart and studied their growth stimulating effect on VSMC. Porcine cardiac tissue was deproteinated with perchloric acid and concentrated with a preparative reversed phase C18 column. Then the extract was separated with a size exclusion column, an anion exchange column, and an affinity column. It was then chromatographed with an anion exchange HPLC and a reversed phase HPLC and a purified substance was obtained. Med. Klinik I, Nephrol. Labor, Univ. Klinik Marien hospital, University of Bochum, Herne, Germany (Luo JK, Wang H, Schlüter H, JankowskifJ, Potthoff W, Tepel M and Zidek W) Using the BrdU method, this substance was shown to have a growth stimulating effect that is dose-dependent on VSMC. Matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) analysis showed that the molecular mass of the substance was 757.0, the same as diadenosine triphosphate (AP 3A). UV spectrum indicated the maximum absorption at 259 nm, similar to that of adenosine. Postsource decay (PSD) MALDI MS showed that the substance contained adenine, adenosine, AMP, ADP, and ATP, respectively. Enzymatic cleavage revealed that phosphates in this molecule connected adenosine in 5' position. It was determined from the above data that the substance was Ap 3A. In this study the existence of Ap 3A was demonstrated in the heart. It has a growth stimulating effect on VSMC.展开更多
A Mueller matrix covers all the polarization information of the measured sample,however the combination of its 16 elements is sometimes not intuitive enough to describe and identify the key characteristics of polariza...A Mueller matrix covers all the polarization information of the measured sample,however the combination of its 16 elements is sometimes not intuitive enough to describe and identify the key characteristics of polarization changes.Within the Poincarésphere system,this study achieves a spatial representation of the Mueller matrix:the Global-Polarization Stokes Ellipsoid(GPSE).With the help of Monte Carlo simulations combined with anisotropic tissue models,three basic characteristic parameters of GPSE are proposed and explained,where the V parameter represents polarization maintenance ability,and the E and D†parameters represent the degree of anisotropy.Furthermore,based on GPSE system,a dynamic analysis of skeletal muscle dehydration process demonstrates the monitoring efect of GPSE from an application perspective,while confrming its robustness and accuracy.展开更多
基金Supported by the National Natural Science Foundation of China, No. 10204014
文摘AIM： To study the relation between acoustic parameters and histological structure of biological tissue and to provide the basis for high-resolution image of biological tissues and quantitative ultrasonic diagnosis of liver disease. METHODS： Ultrasonic imaging and tissue characterization of four normal porcine liver and five cirrhotic liver tissue samples were performed using a high frequency imaging system. RESULTS： The acoustic parameters of cirrhotic liver tissue were larger than those of normal liver tissue. The sound velocity was 1577 m/s in normal liver tissue and 1631 m/s in cirrhotic liver tissue. At 35 MHz, the attenuation coefficient was 3.0 dB/mm in normal liver tissue and 4.1 dB/mm in cirrhotic liver tissue. The backscatter coefficient was 0.00431 dB/Srmm in cirrhotic liver tissue and 0.00303 dB/Srmm in normal liver tissue. The backscatter coefficient increased with the frequency. The high frequency images coincided with their histological features. CONCLUSION： The acoustic parameters, especially the sound backscatter coefficient, are sensitive to the changes of liver tissues and can be used to differentiate between the normal and pathological liver tissues. High frequency image system is a useful device for highresolution image and tissue characterization.
基金This work is supported by the National Natural Science Foundation of China for Prominent Younth(No.59625306)National Emphasis Basis Subject(973.Programn)G1999054309-4.
文摘Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGS). PVA and chitosan were also blended with collagen. The physical and chemical properties of the matrices were characterized by SEM, DSC, and ESCA. L929 cells were implanted on the matrices to show the cytotoxic and the biological characters of the materials. The results indicate that EDC is an effective and non-cytotoxic cross-link reagent, which can replace the common dialdehyde reagent. The attachment of CS can improve the stability of collagen and accelerate cell growth. The addition of PVA can prepare porous matrices with smaller bore size. There are reactions between the chitosan and collagen, and the composite has good biological character. The presence of chitosan can also increase the amount of incorporated CS.
文摘The importance of ligaments in providing joint stability and the incidence of injuries, dictates a need to increase their structural and mechanical properties understanding. Additionally, one of the challenges in the orthopedic industry is to design TKA （total knee arthroplasty） aiming to be soft-tissues friendly. This requires a priori knowledge of physiological knee function, in which the passive stability is achieved and guaranteed by the complex envelope of soft tissues around the joint. Therefore, the knowledge of the mechanical behavior of knee ligaments is fundamental. For this reason, our study aims to define and apply in a pilot study, an ad-hoc methodology to mechanically characterize ligaments of native human knees. The cruciate and collateral ligaments from a fresh frozen cadaver leg were accurately harvested. Each ligament was independently tested during a tensile test at different strain rates, simulating different deformation speeds during gait. Moreover, additional tensile tests until failure were also performed. Axial force and deformation were continuously recorded during each test. Results show that each ligament exhibited own typical non-linear, speed-related behavior. High repeatability in the results is observed among the different repeated tests confirming the robustness of the used methodology. This information will be helpful for clinicians, engineers and researchers to improve the biomechanical knowledge about knee, to develop better implants and to be able to improve the currently available numerical models of the human knee.
文摘Elasticity is an important physical property of human tissues. There is a tremendous difference in elasticity between normal and pathological tissues. Noninvasive evaluation of the elasticity of human tissues would be valuable for clinical practice. Magnetic resonance elastography(MRE)is a recently developed noninvasive imaging technique that can directly visualize and quantitatively measure tissue elasticity. This article reviewed the MRE technique and its current status.
基金supported in part by grants from the National Institutes of Health(NIBIB,R21 EB005321,R01 EB005221,R01 EB009073NCI RC1 CA147096,S.A.B.).
文摘With the development of optical coherence tomography,the application optical coherence elastography(OCE)has gained more and more attention in biomechanics for its unique features including micron-scale resolution,real-time processing,and non-invasive imaging.In this review,one group of OCE techniques,namely dynamic OCE,are introduced and discussed including external dynamic OCE mapping and imaging of ex vivo breast tumor,external dynamic OCE measurement of in vivo human skin,and internal dynamic OCE including acoustomotive OCE and magnetomotive OCE.These techniques overcame some of the major drawbacks of traditional static OCE,and broadened the OCE application fields.Driven by scientific needs to engineer new quantitative methods that utilize the high micron-scale resolution achievable with optics,results of biomechanical properties were obtained from biological tissues.The results suggest potential diagnostic and therapeutic clinical applications.Results from these studies also help our understanding of the relationship between biomechanical variations and functional tissue changes in biological systems.
基金This study is supported by the Chunhui Project(No.Z2015108)the Ministry of Education China,the Sichuan Science and Technology Program(No.2019YFG0196)+2 种基金the high-level personnel launch scientific research projects of Guizhou Institute of Technology(No.XJGC 20150105)the Science&Technology Department of Guizhou Province and Guizhou Institute of Technology Collaborative Fund LH(No.[2015]7104)the invitation for bid Project of Education Department of Guizhou Province KY(No.[2015]360).
文摘The quality of ultrasound scanning images is usually damaged by speckle noise.This paper proposes a method based on local statistics extracted from a histogram to reduce ultrasound speckle through a region growing algorithm.Unlike single statistical moment-based speckle reduction algorithms,this method adaptively smooths the speckle regions while preserving the margin and tissue structure to achieve high detectability.The criterion of a speckle region is defined by the similarity value obtained by matching the histogram of the current processing window and the reference window derived from the speckle region in advance.Then,according to the similarity value and tissue characteristics,the entire image is divided into several levels of speckle-content regions,and adaptive smoothing is performed based on these classification characteristics and the corresponding window size determined by the proposed region growing technique.Tests conducted from phantoms and in vivo images have shown very promising results after a quantitative and qualitative comparison with existing work.
基金Paulino Vacas-Jacques gratefully acknowledges the National Science and Technology Council of Mexico(CONACyT)for the financial support assigned to participate at Saratov State University,grant 172068.The same author thanks the“Centro de Investigaciones en Optica”for partial funding of travel expensesThis research was performed in the framework of the project“Applications of infrared interferometry for biomedical tomography”(CONACyT 2007-I0003-60450).
文摘We have proposed an interferometric setup for biomedical analysis in transillumination modality.Wavelength dependence of optical properties must be considered for selecting source and sample.An expansion of the sample optical properties,around the central wavelength of emission,serves to account for spectral effects.Expected spectral values depend on the central moments of the source,and specific constants associated to the optical properties of the sample.By matching wavelength characteristics of source and sample,a first-order approximation is applicable.In such case,the expected values are exactly the optical properties evaluated at the central wavelength.Furthermore,in the first-order approximation,the transillumination interferometer yields the integrated attenuation of the sample at the central wavelength of emission.We verify the latter assertion by performing a wavelength-dependent Monte Carlo analysis to calculate the response of the transillumination interferometer.Recovered attenuation coefficients,for imaging and characterization scenarios,are in agreement with the value computed at the central wavelength of the source.
文摘A high-speed digital acquisition and wide-band measurement system was used to acquiring and recording the ultrasonic pulse waveforms backscattered from normal and several pathological pig's fresh liver tissues (including ballooning degeneration, fatty degeneration, cirrhosis) in vitro. Some frequency-domain analyses were performed in which integrated backscattering coefficient (IBSC), frequency dependence of backscattering coefficient (FDBSC),and mean spacing (MS) among adjacent scatterers of the tissues were determined.In the experiments the frequency domain was from 3MHz to 7 MHz. The obtained results show that the differences among normal and various pathological tissues cause distinct changes of the measured parameters. The results show that the ultrasonic spectum technique, which can be used in tissue characterization for pathological liver in clinical, has an exciting prospect.
文摘The proliferation of vascular smooth muscle cells (VSMC) plays a role in the maintenance of hypertension and atherosclerosis. Diadenosine polyphosphates have been identified as modulators of the cardiovascular system. We detected the existence of diadenosine polyphosphates in the heart and studied their growth stimulating effect on VSMC. Porcine cardiac tissue was deproteinated with perchloric acid and concentrated with a preparative reversed phase C18 column. Then the extract was separated with a size exclusion column, an anion exchange column, and an affinity column. It was then chromatographed with an anion exchange HPLC and a reversed phase HPLC and a purified substance was obtained. Med. Klinik I, Nephrol. Labor, Univ. Klinik Marien hospital, University of Bochum, Herne, Germany (Luo JK, Wang H, Schlüter H, JankowskifJ, Potthoff W, Tepel M and Zidek W) Using the BrdU method, this substance was shown to have a growth stimulating effect that is dose-dependent on VSMC. Matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) analysis showed that the molecular mass of the substance was 757.0, the same as diadenosine triphosphate (AP 3A). UV spectrum indicated the maximum absorption at 259 nm, similar to that of adenosine. Postsource decay (PSD) MALDI MS showed that the substance contained adenine, adenosine, AMP, ADP, and ATP, respectively. Enzymatic cleavage revealed that phosphates in this molecule connected adenosine in 5' position. It was determined from the above data that the substance was Ap 3A. In this study the existence of Ap 3A was demonstrated in the heart. It has a growth stimulating effect on VSMC.
基金the Science and Technology Research Program of Shenzhen(Nos.JCYJ20200109142820687 and JCYJ20210324120012035)the Cross-research Innovation Fund of the International Graduate School at Shenzhen,Tsinghua University(No.JC2021002)the Russian Science Foundation(No.23-14-00287).
文摘A Mueller matrix covers all the polarization information of the measured sample,however the combination of its 16 elements is sometimes not intuitive enough to describe and identify the key characteristics of polarization changes.Within the Poincarésphere system,this study achieves a spatial representation of the Mueller matrix:the Global-Polarization Stokes Ellipsoid(GPSE).With the help of Monte Carlo simulations combined with anisotropic tissue models,three basic characteristic parameters of GPSE are proposed and explained,where the V parameter represents polarization maintenance ability,and the E and D†parameters represent the degree of anisotropy.Furthermore,based on GPSE system,a dynamic analysis of skeletal muscle dehydration process demonstrates the monitoring efect of GPSE from an application perspective,while confrming its robustness and accuracy.
