A. Makki, A. El-Fishawy, A. Abutaleb, C. Hansen, J. Siegel, S. Kesler
Two algorithms for the detection of small changes between images in a noisy environment are described. The first is a nonlinear image processing procedure for reduction and/or suppression of background (clutter), and the enhancement of the small difference between two images. This procedure is based on the recently developed Pontryagin filter and concepts of adaptive noise cancelling and image-sequence analysis. The second procedure is linear and is based on a lattice filter structure. The performance is evaluated through computer simulations and real images.<>
{"title":"Change-detection in image sequences (medical application)","authors":"A. Makki, A. El-Fishawy, A. Abutaleb, C. Hansen, J. Siegel, S. Kesler","doi":"10.1109/NEBC.1988.19412","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19412","url":null,"abstract":"Two algorithms for the detection of small changes between images in a noisy environment are described. The first is a nonlinear image processing procedure for reduction and/or suppression of background (clutter), and the enhancement of the small difference between two images. This procedure is based on the recently developed Pontryagin filter and concepts of adaptive noise cancelling and image-sequence analysis. The second procedure is linear and is based on a lattice filter structure. The performance is evaluated through computer simulations and real images.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122954297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A computer simulation for vibration of the vocal folds is presented. Free and forced oscillations were studied by imposing an impulse and time varying surface forces. The solution was obtained by a semidiscrete numerical method. A finite-element technique was used for solution of the problem in space and a Crank-Nicholson finite-difference method was used for time integration. Each vocal fold was divided into nine parallel layers of equal thickness where a two-dimensional finite method could be applied and layers were coupled to each other by a string law. Triangular elements of different size were selected such that finger elements appeared in the tip of the fold, where the largest and most probable movement was expected. Two different materials, corresponding to the muscle and cover, were considered in the model of vocal cords. Horizontal and vertical displacements of nodal points were obtained as a function of time. In addition, the response of the system to a sinusoidally varying force was obtained and compared with experimental results of an excised larynx of similar loading for validation of model.<>
{"title":"A finite element simulation of vocal folds vibrations","authors":"F. Alipour-Haghighi, I. Titze","doi":"10.1109/NEBC.1988.19380","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19380","url":null,"abstract":"A computer simulation for vibration of the vocal folds is presented. Free and forced oscillations were studied by imposing an impulse and time varying surface forces. The solution was obtained by a semidiscrete numerical method. A finite-element technique was used for solution of the problem in space and a Crank-Nicholson finite-difference method was used for time integration. Each vocal fold was divided into nine parallel layers of equal thickness where a two-dimensional finite method could be applied and layers were coupled to each other by a string law. Triangular elements of different size were selected such that finger elements appeared in the tip of the fold, where the largest and most probable movement was expected. Two different materials, corresponding to the muscle and cover, were considered in the model of vocal cords. Horizontal and vertical displacements of nodal points were obtained as a function of time. In addition, the response of the system to a sinusoidally varying force was obtained and compared with experimental results of an excised larynx of similar loading for validation of model.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120992579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Hampshire, J. Strohbehn, M.D. McDaniel, J.L. Waugh, D. James
The Rayleigh and Rice-Nakagami probability density functions (PDFs) are generally accepted models for the RF envelope of ultrasonic backscatter from tissue. However, theoretical computations and experimental results from a tissue equivalent phantom and in vivo canine myocardium suggest that these two PDFs are overly simplistic expressions of a more complex scattering process occurring in tissue. This process is modeled more precisely by the Nakagami-M PDF which is a compact expression for the most general form of the two-dimensional random walk satisfying the central limit theorem. An analysis of ultrasonic backscatter from a Rayleigh phantom is presented with initial results from normal myocardium to substantiate this finding and address its implications for a deeper understanding of the phenomenon of ultrasonic scattering in tissue.<>
{"title":"Probability density of myocardial ultrasonic backscatter","authors":"J. Hampshire, J. Strohbehn, M.D. McDaniel, J.L. Waugh, D. James","doi":"10.1109/NEBC.1988.19413","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19413","url":null,"abstract":"The Rayleigh and Rice-Nakagami probability density functions (PDFs) are generally accepted models for the RF envelope of ultrasonic backscatter from tissue. However, theoretical computations and experimental results from a tissue equivalent phantom and in vivo canine myocardium suggest that these two PDFs are overly simplistic expressions of a more complex scattering process occurring in tissue. This process is modeled more precisely by the Nakagami-M PDF which is a compact expression for the most general form of the two-dimensional random walk satisfying the central limit theorem. An analysis of ultrasonic backscatter from a Rayleigh phantom is presented with initial results from normal myocardium to substantiate this finding and address its implications for a deeper understanding of the phenomenon of ultrasonic scattering in tissue.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124994873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Portable muscle stimulators for transcutaneous functional electrical stimulation (FES) are discussed. They provide a single channel of current-controlled output and are intended to be used in the rehabilitation of patients with spinal cord injuries. Several safety features have been incorporated to protect patients from device failure or improper calibration. Six prototypes are currently being used in an FES study. Preliminary results indicate that the stimulators are safe, reliable, and effective.<>
{"title":"A portable current controlled muscle stimulator","authors":"N. Berger, W. Ohley, O. Lemaire, J. Parziale","doi":"10.1109/NEBC.1988.19367","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19367","url":null,"abstract":"Portable muscle stimulators for transcutaneous functional electrical stimulation (FES) are discussed. They provide a single channel of current-controlled output and are intended to be used in the rehabilitation of patients with spinal cord injuries. Several safety features have been incorporated to protect patients from device failure or improper calibration. Six prototypes are currently being used in an FES study. Preliminary results indicate that the stimulators are safe, reliable, and effective.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128367143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flow patterns are investigated in simplified three-dimensional arterial models. The blood is considered as an incompressible Newtonian fluid obeying the Navier-Stokes equations of fluid flow. Therefore, these equations are used as a mathematical model to simulate the blood flow. Since these equations are difficult to solve analytically, a computational approach is utilized. To use this approach a suitable treatment of the complex arterial geometry is required. A proper numerical technique is also needed to solve the blood flow equations. A curvilinear coordinate system is used to solve the problem of geometry where an algebraic grid generation technique is used to generate the arterial geometry. The Navier-Stokes equations are written in the new coordinates and a computer program is developed utilizing the space marching method to integrate these equations for steady blood flow. The program is used to solve many problems that are of interest to hemodynamic studies. Results for flow with separated region (89% stenosis) and flow with secondary velocities (curved aneurysm) are presented and discussed. These results show the ability of the numerical methods to calculate the velocity fields and wall shear stress for three-dimensional arterial configurations.<>
{"title":"Numerical simulation of blood flow through arteries","authors":"A. Mazher, J. Ekaterinaris","doi":"10.1109/NEBC.1988.19404","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19404","url":null,"abstract":"Flow patterns are investigated in simplified three-dimensional arterial models. The blood is considered as an incompressible Newtonian fluid obeying the Navier-Stokes equations of fluid flow. Therefore, these equations are used as a mathematical model to simulate the blood flow. Since these equations are difficult to solve analytically, a computational approach is utilized. To use this approach a suitable treatment of the complex arterial geometry is required. A proper numerical technique is also needed to solve the blood flow equations. A curvilinear coordinate system is used to solve the problem of geometry where an algebraic grid generation technique is used to generate the arterial geometry. The Navier-Stokes equations are written in the new coordinates and a computer program is developed utilizing the space marching method to integrate these equations for steady blood flow. The program is used to solve many problems that are of interest to hemodynamic studies. Results for flow with separated region (89% stenosis) and flow with secondary velocities (curved aneurysm) are presented and discussed. These results show the ability of the numerical methods to calculate the velocity fields and wall shear stress for three-dimensional arterial configurations.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128777646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Ha, J. Roper, H. Mallett, J. Ferreiro, C. Lucas, G. Henry
The effects of dopamine on pulmonary and systematic vascular beds were investigated in 8 anesthetized goats (mean age 5+or-1 weeks). Pulmonary artery, aortic, left atrial, and central venous pressures and pulmonary and aortic flows were recorded simultaneously during a 10-minute baseline period and while infusion dopamine at 5, 10, 20, 40 160, and 320 mu g/kg/min. Pulmonary vascular resistance increased significantly at the 20 and 40 mu /kg/min infusion rates, while systemic vascular resistance decreased significantly at these rates. Characteristic impedances indicate generally increased trends. The pulmonary global reflection index indicates increased impedance mismatch at the high infusion rates, while the opposite is true for the systemic reflection index. Right heart work and the energy costs of transporting 1 cm/sup 3/ blood exceed systemic work and energy costs at the high rates of increase the resting tone of the pulmonary vascular bed, while the effect on systemic vascular tone remains unclear. The finding that the work and energy requirements of the heart are substantially increased at the higher infusion rates could affect the therapeutic value of dopamine use at these rates.<>
研究了多巴胺对8只麻醉山羊(平均年龄5±1周龄)肺和系统血管床的影响。同时记录10分钟基线期间肺动脉、主动脉、左心房和中心静脉压以及肺动脉和主动脉流量，同时以5、10、20、40、160和320 μ g/kg/min注射多巴胺。在20和40 mu /kg/min输注速率下，肺血管阻力显著增加，而全身血管阻力显著降低。特征阻抗一般显示增加的趋势。肺整体反射指数表明在高输注速率下阻抗失配增加，而全身反射指数则相反。右心功和输送1cm /sup /血的能量成本在增加肺血管床静息张力的高速率下超过全身功和能量成本，而对全身血管张力的影响尚不清楚。在较高的输注速率下，心脏的功和能量需求显著增加，这一发现可能会影响在这些速率下使用多巴胺的治疗价值。
{"title":"Dopamine effects on infant pulmonary and systemic vasculature","authors":"B. Ha, J. Roper, H. Mallett, J. Ferreiro, C. Lucas, G. Henry","doi":"10.1109/NEBC.1988.19388","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19388","url":null,"abstract":"The effects of dopamine on pulmonary and systematic vascular beds were investigated in 8 anesthetized goats (mean age 5+or-1 weeks). Pulmonary artery, aortic, left atrial, and central venous pressures and pulmonary and aortic flows were recorded simultaneously during a 10-minute baseline period and while infusion dopamine at 5, 10, 20, 40 160, and 320 mu g/kg/min. Pulmonary vascular resistance increased significantly at the 20 and 40 mu /kg/min infusion rates, while systemic vascular resistance decreased significantly at these rates. Characteristic impedances indicate generally increased trends. The pulmonary global reflection index indicates increased impedance mismatch at the high infusion rates, while the opposite is true for the systemic reflection index. Right heart work and the energy costs of transporting 1 cm/sup 3/ blood exceed systemic work and energy costs at the high rates of increase the resting tone of the pulmonary vascular bed, while the effect on systemic vascular tone remains unclear. The finding that the work and energy requirements of the heart are substantially increased at the higher infusion rates could affect the therapeutic value of dopamine use at these rates.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126432748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A feasibility study of a noninvasive intraocular tonometer consisting of a linear voltage differential transformer (LVDT) for measurement of intracranial pressure (ICP) is discussed. The feasibility was assessed by measuring ICP through an artificially created fontanel in pigs. An LVDT deflection corresponds directly with the response of an invasive pressure transducer inserted into the cerebrospinal fluid. The LVDT can also provide a discrete measurement of intracranial pressure. A handheld LVDT tonometer would allow for a quick noninvasive assessment of ICP, and serve as a screening process for infants at risk of abnormal ICP.<>
{"title":"Assessment of intracranial pressure","authors":"C. Jensen, J. LaCourse","doi":"10.1109/NEBC.1988.19365","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19365","url":null,"abstract":"A feasibility study of a noninvasive intraocular tonometer consisting of a linear voltage differential transformer (LVDT) for measurement of intracranial pressure (ICP) is discussed. The feasibility was assessed by measuring ICP through an artificially created fontanel in pigs. An LVDT deflection corresponds directly with the response of an invasive pressure transducer inserted into the cerebrospinal fluid. The LVDT can also provide a discrete measurement of intracranial pressure. A handheld LVDT tonometer would allow for a quick noninvasive assessment of ICP, and serve as a screening process for infants at risk of abnormal ICP.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114809906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A noninvasive flicker fusion device to measure impairment due to alcohol or other drugs is discussed. The flicker fusion uses an array of light-emitting diodes and is based on identification. It operates slightly below threshold frequencies and requires a subject to distinguish between patterns of modulated lights and constant background lights.<>
{"title":"A flicker fusion device for measuring alcohol impairment","authors":"B.W. Giroux, A. Drake","doi":"10.1109/NEBC.1988.19327","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19327","url":null,"abstract":"A noninvasive flicker fusion device to measure impairment due to alcohol or other drugs is discussed. The flicker fusion uses an array of light-emitting diodes and is based on identification. It operates slightly below threshold frequencies and requires a subject to distinguish between patterns of modulated lights and constant background lights.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130639999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is shown that over a wide flow range, phasic changes in renal volume and the maximum rate of volume change may be reasonably predicted from changes in renal conductance using a model which assumes homogeneous geometric changes. However, the relationship deteriorates at high pump rates, stroke volumes, and therefore mean flow values. It is suggested that the expansion of the arteriolar bed occurring at the higher flow rates and stroke volumes causes a decrease in arteriolar compliance, which in turn causes a greater portion of the volume pulsation to be transmitted to the venous system, where the geometric assumptions may no longer be valid. The independent effect of rate is more difficult to explain. It may be due to a frequency resonance effect in which, at rates greater than the resonant frequency, the vascular bed remains at a greater state of expansion, again reducing arteriolar compliance and transmitting a greater portion of the volume pulsation to the venous system.<>
{"title":"Renal admittance plethysmography","authors":"L. Marks, D. Anaise, M. Yland","doi":"10.1109/NEBC.1988.19362","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19362","url":null,"abstract":"It is shown that over a wide flow range, phasic changes in renal volume and the maximum rate of volume change may be reasonably predicted from changes in renal conductance using a model which assumes homogeneous geometric changes. However, the relationship deteriorates at high pump rates, stroke volumes, and therefore mean flow values. It is suggested that the expansion of the arteriolar bed occurring at the higher flow rates and stroke volumes causes a decrease in arteriolar compliance, which in turn causes a greater portion of the volume pulsation to be transmitted to the venous system, where the geometric assumptions may no longer be valid. The independent effect of rate is more difficult to explain. It may be due to a frequency resonance effect in which, at rates greater than the resonant frequency, the vascular bed remains at a greater state of expansion, again reducing arteriolar compliance and transmitting a greater portion of the volume pulsation to the venous system.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130645901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A method has been developed to determine local fiber orientations from scanning electron microscope images of connective tissues. The digitized image is convolved with gradient operators to locate edges and determine their direction. The local directions of the fibers are found and collected into a histogram representing a fiber-orientation distribution function.<>
{"title":"A method for determining fiber direction in soft tissues","authors":"H. Ault, A. Hoffman, P. Grigg","doi":"10.1109/NEBC.1988.19393","DOIUrl":"https://doi.org/10.1109/NEBC.1988.19393","url":null,"abstract":"A method has been developed to determine local fiber orientations from scanning electron microscope images of connective tissues. The digitized image is convolved with gradient operators to locate edges and determine their direction. The local directions of the fibers are found and collected into a histogram representing a fiber-orientation distribution function.<<ETX>>","PeriodicalId":165980,"journal":{"name":"Proceedings of the 1988 Fourteenth Annual Northeast Bioengineering Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125654166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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