Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.652837
S. Kovacs, A. Hall
Traditional analysis of the cyclic left ventricular (LV) pressure contour utilizes only a small amount of its total information content. For optimal quantitation of LV function maximal information extraction from the contour is desirable. To achieve this, we utilized phase plane analysis to characterize /spl tau/, the time constant of isovolumic relaxation. Exponential pressure decay in time appears as a linear relation in the phase plane (dP/dt vs. P). The cyclic LV pressure generates a limit cycle in the phase plane, whose isovolumic relaxation portion was analyzed to elucidate the pressure decay process. In 4 of 19 subjects isovolumic pressure decline could not be accurately fit using the standard exponential decay assumption. Hence, phase plane analysis provides new information about isovolumic relaxation.
传统的循环左室(LV)压力轮廓分析仅利用了其总信息量的一小部分。为了优化LV函数的定量，需要从轮廓中提取最大的信息。为了实现这一点，我们利用相平面分析来表征等体积弛豫的时间常数/spl tau/。压力随时间的指数衰减在相平面上呈线性关系(dP/dt vs. P)，循环低压压力在相平面上产生一个极限环，分析了其等体积弛豫部分来解释压力衰减过程。在19名受试者中，有4人的等体积压力下降不能用标准指数衰减假设准确拟合。因此，相平面分析提供了有关等体积弛豫的新信息。
{"title":"Phase plane analysis of isovolumic relaxation","authors":"S. Kovacs, A. Hall","doi":"10.1109/IEMBS.1996.652837","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652837","url":null,"abstract":"Traditional analysis of the cyclic left ventricular (LV) pressure contour utilizes only a small amount of its total information content. For optimal quantitation of LV function maximal information extraction from the contour is desirable. To achieve this, we utilized phase plane analysis to characterize /spl tau/, the time constant of isovolumic relaxation. Exponential pressure decay in time appears as a linear relation in the phase plane (dP/dt vs. P). The cyclic LV pressure generates a limit cycle in the phase plane, whose isovolumic relaxation portion was analyzed to elucidate the pressure decay process. In 4 of 19 subjects isovolumic pressure decline could not be accurately fit using the standard exponential decay assumption. Hence, phase plane analysis provides new information about isovolumic relaxation.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75009647","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.652731
T. Matozaki, A. Tanishita, T. Ikeguchi
Image enhancement of the blurred area masked by high contrast image on X-ray chest radiography, is very important for physician's diagnosis. We study the possibility of image enhancement of the masked area in spite of the size and the position of the masked area, using wavelet analysis, automatically. The image signals are decomposed to wavelet representation which lies between the spatial and the Fourier domain. The wavelet coefficient can be modified locally referring to the density of blurred image on both domains. As it is possible to keep information referring to the coordinate on the image, using features of localization of the base functions, we could transform inversively the decomposed data through modification of the coefficient. As a result, we could recognize more clearly properties of region of mediastium and lung, respectively.
{"title":"Image enhancement of chest radiography using wavelet analysis","authors":"T. Matozaki, A. Tanishita, T. Ikeguchi","doi":"10.1109/IEMBS.1996.652731","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652731","url":null,"abstract":"Image enhancement of the blurred area masked by high contrast image on X-ray chest radiography, is very important for physician's diagnosis. We study the possibility of image enhancement of the masked area in spite of the size and the position of the masked area, using wavelet analysis, automatically. The image signals are decomposed to wavelet representation which lies between the spatial and the Fourier domain. The wavelet coefficient can be modified locally referring to the density of blurred image on both domains. As it is possible to keep information referring to the coordinate on the image, using features of localization of the base functions, we could transform inversively the decomposed data through modification of the coefficient. As a result, we could recognize more clearly properties of region of mediastium and lung, respectively.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77038353","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.651917
N. Bruining, C. Birgelen, Francesco Prati, M. Mallus, W. Li, W. D. Hoed, M. Patijn, P. D. Feyter, P. Serruys, J. Roelandt
Most systems used for three-dimensional (3-D) of two-dimensional intracoronary ultrasound (ICUS) images are based on an image acquisition with a pull-back device which withdraws the catheter with a constant speed, nor taking account of cardiac motion and coronary dynamics/pulsation. Cyclic changes of the vessel dimensions and the movement of the catheter inside the vessel result in artifacts and inaccuracies of quantitative measurements. This phenomenon limits accuracy and resolution when an attempt of 3-D reconstruction is performed, since images obtained in different phases of the cardiac cycle are compiled. To overcome these limitations the authors developed a custom-designed pull-back device driven by a stepping motor, which is controlled by a steering logic ensuring an ECG-gated image acquisition.
{"title":"Dynamic three-dimensional reconstruction of ICUS images based on an ECG-gated pull-back device","authors":"N. Bruining, C. Birgelen, Francesco Prati, M. Mallus, W. Li, W. D. Hoed, M. Patijn, P. D. Feyter, P. Serruys, J. Roelandt","doi":"10.1109/IEMBS.1996.651917","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.651917","url":null,"abstract":"Most systems used for three-dimensional (3-D) of two-dimensional intracoronary ultrasound (ICUS) images are based on an image acquisition with a pull-back device which withdraws the catheter with a constant speed, nor taking account of cardiac motion and coronary dynamics/pulsation. Cyclic changes of the vessel dimensions and the movement of the catheter inside the vessel result in artifacts and inaccuracies of quantitative measurements. This phenomenon limits accuracy and resolution when an attempt of 3-D reconstruction is performed, since images obtained in different phases of the cardiac cycle are compiled. To overcome these limitations the authors developed a custom-designed pull-back device driven by a stepping motor, which is controlled by a steering logic ensuring an ECG-gated image acquisition.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89224627","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.647499
H. Oka
This study aims at the measurement and estimation of muscle fatigue. Viscoelasticity is calculated from the biomechanical impedance spectrum and EMG is measured. When isometric and isotonic muscle fatigue are created in the forearm, elasticity, viscosity and IEMG increase, and MNF decreases. Each variable change rate, however, is different in order to estimate muscle fatigue synthetically, PCA is calculated by using viscoelasticity and EMG. As a result, it is suggested that the 1st component expresses a change in muscle stiffness and the 2nd component expresses objective fatigue. The slope of the approximation line seems to correspond to the degree of muscle fatigue.
{"title":"Estimation of muscle fatigue by using EMG and muscle stiffness","authors":"H. Oka","doi":"10.1109/IEMBS.1996.647499","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.647499","url":null,"abstract":"This study aims at the measurement and estimation of muscle fatigue. Viscoelasticity is calculated from the biomechanical impedance spectrum and EMG is measured. When isometric and isotonic muscle fatigue are created in the forearm, elasticity, viscosity and IEMG increase, and MNF decreases. Each variable change rate, however, is different in order to estimate muscle fatigue synthetically, PCA is calculated by using viscoelasticity and EMG. As a result, it is suggested that the 1st component expresses a change in muscle stiffness and the 2nd component expresses objective fatigue. The slope of the approximation line seems to correspond to the degree of muscle fatigue.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78958047","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.651926
Xi-Zhang Lin, Yung-Nien Sun, M. Horng, Xiao-Zhen Guo
Liver biopsy is the gold standard for evaluation of liver diseases. The severity of fibrosis is considered the stage of chronic liver disease. However, it is evaluated by subjective description or semiquantitation. The authors developed an automatic image analysis system, which including a microscope, computer-driven slide-driver, and a software system for image acquisition, processing and data analysis. The automatic image analysis system deals mainly with color image segmentation. The severity of liver fibrosis is reported as the percentage of the entire fibrous area to the whole liver tissue area. Thirty-one liver needle biopsy specimens are used for this study. The results from computer morphometry were compared with that from colorimetric method and Knodell's score. Pearson correlation and Spearman rank test revealed that the Kondell's score and colorimetric method are significantly correlated with the result of computer morphometry. The authors found that the system is a reliable tool for evaluating the severity of liver fibrosis.
{"title":"Computer morphometry for liver fibrosis using an automatic image analysis system","authors":"Xi-Zhang Lin, Yung-Nien Sun, M. Horng, Xiao-Zhen Guo","doi":"10.1109/IEMBS.1996.651926","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.651926","url":null,"abstract":"Liver biopsy is the gold standard for evaluation of liver diseases. The severity of fibrosis is considered the stage of chronic liver disease. However, it is evaluated by subjective description or semiquantitation. The authors developed an automatic image analysis system, which including a microscope, computer-driven slide-driver, and a software system for image acquisition, processing and data analysis. The automatic image analysis system deals mainly with color image segmentation. The severity of liver fibrosis is reported as the percentage of the entire fibrous area to the whole liver tissue area. Thirty-one liver needle biopsy specimens are used for this study. The results from computer morphometry were compared with that from colorimetric method and Knodell's score. Pearson correlation and Spearman rank test revealed that the Kondell's score and colorimetric method are significantly correlated with the result of computer morphometry. The authors found that the system is a reliable tool for evaluating the severity of liver fibrosis.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80039529","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.652713
Jie Feng, Wei-Chung Lin, Chin-Tu Chen
A new segmentation approach is proposed to integrate both the directional fractal dimension and the histogram analyses. To detect weaker features, adaptive local enhancement is performed. This results in a more accurate segmentation capable of detecting fine and subtle details in a noisy image.
{"title":"Integrating fractal and intensity in image segmentation","authors":"Jie Feng, Wei-Chung Lin, Chin-Tu Chen","doi":"10.1109/IEMBS.1996.652713","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652713","url":null,"abstract":"A new segmentation approach is proposed to integrate both the directional fractal dimension and the histogram analyses. To detect weaker features, adaptive local enhancement is performed. This results in a more accurate segmentation capable of detecting fine and subtle details in a noisy image.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81280186","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.652653
A. Liavas, G. Moustakides, G. Henning, E. Psarakis, P. Husar
In this paper the authors develop a new method, based on the periodogram of a time-series, for the detection of steady-state VEPs. The method tests the data for the presence of hidden periodic components, which correspond to steady-state VEPs.
{"title":"On the detection of steady-state visually evoked potentials","authors":"A. Liavas, G. Moustakides, G. Henning, E. Psarakis, P. Husar","doi":"10.1109/IEMBS.1996.652653","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652653","url":null,"abstract":"In this paper the authors develop a new method, based on the periodogram of a time-series, for the detection of steady-state VEPs. The method tests the data for the presence of hidden periodic components, which correspond to steady-state VEPs.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78711993","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.652822
A. de Jongh, F. Claydon
The objective of this study is to determine if transvenous defibrillation simulations can be simplified by reducing the size of the volume conductor model. The study is implemented with a physiologically realistic 3-D finite element model of the human thorax. The model computes potential distributions within the heart from a knowledge of defibrillation shock strength, defibrillation electrode location, and the relative conductivities of the interior thorax. Results are compared between a model of the entire torso and a model consisting only of the heart surrounded by a spherical shell. Comparison of the potential distributions within the heart between the two models yielded a root mean square error of 13.696 and a correlation coefficient of 0.995. For the finite element solution, storage requirements were decreased by a factor of 4 and computational time was reduced by a factor of 15. These results indicate that for transvenous defibrillation simulations the size of the model can be greatly reduced by excluding the interior structures of the torso external to the heart. In addition, the results suggests that interior structures such as the lungs may not affect the potential distributions within the heart during transvenous defibrillation.
{"title":"Reducing mesh size for finite element modeling of transvenous defibrillation","authors":"A. de Jongh, F. Claydon","doi":"10.1109/IEMBS.1996.652822","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652822","url":null,"abstract":"The objective of this study is to determine if transvenous defibrillation simulations can be simplified by reducing the size of the volume conductor model. The study is implemented with a physiologically realistic 3-D finite element model of the human thorax. The model computes potential distributions within the heart from a knowledge of defibrillation shock strength, defibrillation electrode location, and the relative conductivities of the interior thorax. Results are compared between a model of the entire torso and a model consisting only of the heart surrounded by a spherical shell. Comparison of the potential distributions within the heart between the two models yielded a root mean square error of 13.696 and a correlation coefficient of 0.995. For the finite element solution, storage requirements were decreased by a factor of 4 and computational time was reduced by a factor of 15. These results indicate that for transvenous defibrillation simulations the size of the model can be greatly reduced by excluding the interior structures of the torso external to the heart. In addition, the results suggests that interior structures such as the lungs may not affect the potential distributions within the heart during transvenous defibrillation.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77362076","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.656861
M. Kikuchi, S. Kayashima, N. Ito, T. Arai
New transcutaneous monitoring methods for biochemical substances such as blood glucose and lactate have been developed by using a suction effusion fluid (SEF) collecting technique with an ion-sensitive field-effect transistor for blood glucose, and with a micro-planar amperometric biosensor for lactate respectively. Firstly, blood glucose change during the 75-g oral glucose tolerance test (OGTT) was monitored by suction effusion fluid (SEF) sampling in 5 patients with type II diabetes. Secondly, the authors have also developed a micro planar biosensor for determining lactate concentration in very small sample. The biosensor utilizes a lactate oxidase immobilized membrane on a micro planar platinum electrode to yield a lactate sensor. Both glucose and lactate concentrations measured with SEF showed good correlation with those obtained directly from whole blood.
{"title":"Transcutaneous biochemical substance monitoring based on biosensors-blood glucose and lactate","authors":"M. Kikuchi, S. Kayashima, N. Ito, T. Arai","doi":"10.1109/IEMBS.1996.656861","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.656861","url":null,"abstract":"New transcutaneous monitoring methods for biochemical substances such as blood glucose and lactate have been developed by using a suction effusion fluid (SEF) collecting technique with an ion-sensitive field-effect transistor for blood glucose, and with a micro-planar amperometric biosensor for lactate respectively. Firstly, blood glucose change during the 75-g oral glucose tolerance test (OGTT) was monitored by suction effusion fluid (SEF) sampling in 5 patients with type II diabetes. Secondly, the authors have also developed a micro planar biosensor for determining lactate concentration in very small sample. The biosensor utilizes a lactate oxidase immobilized membrane on a micro planar platinum electrode to yield a lactate sensor. Both glucose and lactate concentrations measured with SEF showed good correlation with those obtained directly from whole blood.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72623694","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}
Pub Date : 1996-12-01DOI: 10.1109/IEMBS.1996.657034
R. Kirsch, A. M. Acosta, E. Perreault, W. Memberg, M. Keith, P. Crago
Tetraplegia resulting from cervical spinal cord injury typically leaves the muscles paralyzed, with the resulting loss extension function. Elbow extension is for many daily activities, important in the rehabilitation of the spinal cord injured individual. This paper compares the widely used surgical transfer of the posterior deltoid muscle, which restores voluntary control over elbow extension, to a technique based on functional neuromuscular stimulation (FNS) of the triceps muscles. Both methods were found to restore a modest level of elbow extension. The posterior deltoid transfer produced variable results and the resulting elbow extension moments were strongly dependent on shoulder position.
{"title":"Approaches for restoring elbow extension in tetraplegia: muscle tendon transfer and functional neuromuscular stimulation","authors":"R. Kirsch, A. M. Acosta, E. Perreault, W. Memberg, M. Keith, P. Crago","doi":"10.1109/IEMBS.1996.657034","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.657034","url":null,"abstract":"Tetraplegia resulting from cervical spinal cord injury typically leaves the muscles paralyzed, with the resulting loss extension function. Elbow extension is for many daily activities, important in the rehabilitation of the spinal cord injured individual. This paper compares the widely used surgical transfer of the posterior deltoid muscle, which restores voluntary control over elbow extension, to a technique based on functional neuromuscular stimulation (FNS) of the triceps muscles. Both methods were found to restore a modest level of elbow extension. The posterior deltoid transfer produced variable results and the resulting elbow extension moments were strongly dependent on shoulder position.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73642540","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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