Pub Date : 1988-11-01DOI: 10.1109/IEMBS.1988.94436
P. Ershler, R. Lux, L. Green, G. Caputo, D. Parker
ECG (electrocardiogram) inverse solutions require accurate determination of three-dimensional torso, heart, and electrode geometries. Magnetic resonance imaging (MRI) provides a noninvasive method for obtaining this information. Subjects initially undergo body surface potential mapping using a 195-channel data recording system. Limitations imposed by the intense magnetic field of the imaging system require that the metallic recording electrodes be replaced with nonmetallic oil-filled phantom electrodes. These are easily delineated in the MRI images. Transverse MRI sections of the subject are imaged at 10-mm intervals. Digital data representing the resulting images are transferred to a Macintosh II computer for definition of surface boundaries. This is a practical technique for obtaining geometrical data for ECG inverse solutions.<>
{"title":"Determination of three-dimensional torso, heart and electrode geometries from magnetic resonance images","authors":"P. Ershler, R. Lux, L. Green, G. Caputo, D. Parker","doi":"10.1109/IEMBS.1988.94436","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94436","url":null,"abstract":"ECG (electrocardiogram) inverse solutions require accurate determination of three-dimensional torso, heart, and electrode geometries. Magnetic resonance imaging (MRI) provides a noninvasive method for obtaining this information. Subjects initially undergo body surface potential mapping using a 195-channel data recording system. Limitations imposed by the intense magnetic field of the imaging system require that the metallic recording electrodes be replaced with nonmetallic oil-filled phantom electrodes. These are easily delineated in the MRI images. Transverse MRI sections of the subject are imaged at 10-mm intervals. Digital data representing the resulting images are transferred to a Macintosh II computer for definition of surface boundaries. This is a practical technique for obtaining geometrical data for ECG inverse solutions.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130244452","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94424
R. Macleod, B. Hoyt, J. Sherwood, P. MacInnis, R. Potter, B. Horáček
A low-noise multichannel recording system for simultaneously registering up to 256 ECG (electrocardiogram) signals in digital form is described. The unit's features include: patient isolation and radiolucent electrodes required for use during cardiac catherization and angioplasty procedures; continuous data collection over several minutes; gain and sampling frequency under software control; and flexible, modular design. The mapping system consists of three physically separate units: the bedside unit, the controller and communications interface, and the computer. The method chosen to ensure adequate patient isolation and still maintain sufficient sensitivity and signal/noise characteristics is to isolate the entire input stage of the recording system and power it with rechargeable batteries.<>
{"title":"A body surface mapping unit for recording during coronary angioplasty","authors":"R. Macleod, B. Hoyt, J. Sherwood, P. MacInnis, R. Potter, B. Horáček","doi":"10.1109/IEMBS.1988.94424","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94424","url":null,"abstract":"A low-noise multichannel recording system for simultaneously registering up to 256 ECG (electrocardiogram) signals in digital form is described. The unit's features include: patient isolation and radiolucent electrodes required for use during cardiac catherization and angioplasty procedures; continuous data collection over several minutes; gain and sampling frequency under software control; and flexible, modular design. The mapping system consists of three physically separate units: the bedside unit, the controller and communications interface, and the computer. The method chosen to ensure adequate patient isolation and still maintain sufficient sensitivity and signal/noise characteristics is to isolate the entire input stage of the recording system and power it with rechargeable batteries.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124175772","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.95283
L. Fogelson, L. Tung, N. Thakor
The authors investigated the electrophysiological consequences of high currents on isolated strips of cardiac muscle. The objective was to measure the graded changes in intracellular action potentials-amplitude, duration, excitability, conduction velocity-resulting from the various levels of electrical shock typically used in defibrillation, cardioversion, and ablation. Following the shock, reversible injury is observed, whose severity is graded in proportion to shock strength. Smaller shocks (below 500 ma/cm/sup 2/, 10 ms) caused depression in action potential amplitude, duration, and propagation velocity. The degree of depression and the time course for complete recovery (0-50-s duration), followed by an action potential recovery phase similar to that observed for the smaller shocks. These graded effects can in conjunction with the whole heart description, of the current densities during defibrillation, permit an estimation of the total volume of tissue subject to inexcitability, reduced propagation velocity, shortened duration, and depressed action potentials.<>
{"title":"Electrophysiologic depression in myocardium by defibrillation-level shocks","authors":"L. Fogelson, L. Tung, N. Thakor","doi":"10.1109/IEMBS.1988.95283","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.95283","url":null,"abstract":"The authors investigated the electrophysiological consequences of high currents on isolated strips of cardiac muscle. The objective was to measure the graded changes in intracellular action potentials-amplitude, duration, excitability, conduction velocity-resulting from the various levels of electrical shock typically used in defibrillation, cardioversion, and ablation. Following the shock, reversible injury is observed, whose severity is graded in proportion to shock strength. Smaller shocks (below 500 ma/cm/sup 2/, 10 ms) caused depression in action potential amplitude, duration, and propagation velocity. The degree of depression and the time course for complete recovery (0-50-s duration), followed by an action potential recovery phase similar to that observed for the smaller shocks. These graded effects can in conjunction with the whole heart description, of the current densities during defibrillation, permit an estimation of the total volume of tissue subject to inexcitability, reduced propagation velocity, shortened duration, and depressed action potentials.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125231152","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94604
J. M. Bauer, N. A. Alvarez, D. McPherson, R. A. Stein
Segmentation of coronary arterial lumen and wall boundaries in high-frequency echocardiographic (HFE) images has been hampered by operator bias and prolonged time required for manual segmentation methods. To overcome these problems, a two-part computer algorithm has been developed to aid HFE image segmentation. This algorithm is accurate when compared to manual methods and histologic data.<>
{"title":"Computer aided segmentation of high frequency echocardiographic images","authors":"J. M. Bauer, N. A. Alvarez, D. McPherson, R. A. Stein","doi":"10.1109/IEMBS.1988.94604","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94604","url":null,"abstract":"Segmentation of coronary arterial lumen and wall boundaries in high-frequency echocardiographic (HFE) images has been hampered by operator bias and prolonged time required for manual segmentation methods. To overcome these problems, a two-part computer algorithm has been developed to aid HFE image segmentation. This algorithm is accurate when compared to manual methods and histologic data.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130912677","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94630
T. Daloze, G. Fink, H. Brunengraber, M.J. Corinthios
A biological model of ketone body metabolism in the rat heart highlights pseudoketogenesis caused by reversible activation of acetoacetate. A mathematical system based on differential equations of isotopic fluxes is solved numerically. Different sets of unknown kinetic constants cannot be discriminated because of concentration patterns, but these patterns can be further analyzed. System poles are located by a fast Z-transform algorithm. The Z plane is scanned along constant damping contours, using an efficient fast Fourier transform algorithm. This simulation and Z-domain scanning approach reduce the need for subjective analysis of experimental data.<>
{"title":"Metabolic system identification using simulation and fast Fourier transformation","authors":"T. Daloze, G. Fink, H. Brunengraber, M.J. Corinthios","doi":"10.1109/IEMBS.1988.94630","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94630","url":null,"abstract":"A biological model of ketone body metabolism in the rat heart highlights pseudoketogenesis caused by reversible activation of acetoacetate. A mathematical system based on differential equations of isotopic fluxes is solved numerically. Different sets of unknown kinetic constants cannot be discriminated because of concentration patterns, but these patterns can be further analyzed. System poles are located by a fast Z-transform algorithm. The Z plane is scanned along constant damping contours, using an efficient fast Fourier transform algorithm. This simulation and Z-domain scanning approach reduce the need for subjective analysis of experimental data.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133651902","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94396
S. P. Reddy, L. Shyu, J. Nagel, N. Schneiderman
The authors used the impedance cardiogram (ICG), the phonocardiogram (PCG), and the electrocardiogram (ECG) to determine stroke volume and systolic time intervals. Comparisons between a fully automated PC/AT-based signal processing system and a computer-assisted visual detection processing system revealed comparable means, standard errors, correlations (Spearman r), and reliability (Chronbach's alpha ) coefficients on all relevant parameters. Other analyses confirmed the utility of using Q onset to mark the beginning of ventricular systole, the B point of the ICG to denote the aortic opening, and end diastole as the reference for determining the amplitude of dZ/dt/sub mzx/.<>
{"title":"Improved reliability of impedance cardiography by new signal processing techniques","authors":"S. P. Reddy, L. Shyu, J. Nagel, N. Schneiderman","doi":"10.1109/IEMBS.1988.94396","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94396","url":null,"abstract":"The authors used the impedance cardiogram (ICG), the phonocardiogram (PCG), and the electrocardiogram (ECG) to determine stroke volume and systolic time intervals. Comparisons between a fully automated PC/AT-based signal processing system and a computer-assisted visual detection processing system revealed comparable means, standard errors, correlations (Spearman r), and reliability (Chronbach's alpha ) coefficients on all relevant parameters. Other analyses confirmed the utility of using Q onset to mark the beginning of ventricular systole, the B point of the ICG to denote the aortic opening, and end diastole as the reference for determining the amplitude of dZ/dt/sub mzx/.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131966151","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.95168
J. Chelsom, Tim Ellis, Ewart R. Carson, D. Cramp
An intelligent knowledge-based system is being developed to assist clinicians with the interpretation of the results of blood-gas analysis in an intensive care unit. The system links directly to an automated blood-gas analyzer for data transfer, thus reducing the time-consuming interaction between computer and clinician. Knowledge held in frames is manipulated by a blackboard system to produce rapid diagnosis of acid-base disorders and underlying diseases. Deeper knowledge of the domain, held in a semantic network, is used to provide detailed explanation of the system's conclusions and to answer general queries about acid-base physiology.<>
{"title":"Blood gas analysis: a knowledge-based adviser for the interpretation of results","authors":"J. Chelsom, Tim Ellis, Ewart R. Carson, D. Cramp","doi":"10.1109/IEMBS.1988.95168","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.95168","url":null,"abstract":"An intelligent knowledge-based system is being developed to assist clinicians with the interpretation of the results of blood-gas analysis in an intensive care unit. The system links directly to an automated blood-gas analyzer for data transfer, thus reducing the time-consuming interaction between computer and clinician. Knowledge held in frames is manipulated by a blackboard system to produce rapid diagnosis of acid-base disorders and underlying diseases. Deeper knowledge of the domain, held in a semantic network, is used to provide detailed explanation of the system's conclusions and to answer general queries about acid-base physiology.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134015193","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94863
J. Chen, J. Vandewalle, W. Sansen, G. Vantrappen, J. Janssens
The recording of human gastric myoelectrical activity by means of cutaneous electrodes attached on the abdominal skin, called electrogastrography (EGG), provides a noninvasive method of studying the electrogastric behavior. The normal frequency of the gastric signal is about 0.05 Hz. However, sudden changes of its frequency have been observed and are generally considered to be related to the gastric motility disorder. This suggests that spectral analysis could serve as a valuable tool for practical purposes. An autoregressive moving-average spectral method is presented. It is based on the adaptive IIR filter and therefore provides both time and frequency information of the signal. The method has been applied to the running spectral analysis of the cutaneous EGG signals. The spectral analysis of the postprandial EGGs is presented.<>
{"title":"On-line spectral analysis of electrogastrographical signals","authors":"J. Chen, J. Vandewalle, W. Sansen, G. Vantrappen, J. Janssens","doi":"10.1109/IEMBS.1988.94863","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94863","url":null,"abstract":"The recording of human gastric myoelectrical activity by means of cutaneous electrodes attached on the abdominal skin, called electrogastrography (EGG), provides a noninvasive method of studying the electrogastric behavior. The normal frequency of the gastric signal is about 0.05 Hz. However, sudden changes of its frequency have been observed and are generally considered to be related to the gastric motility disorder. This suggests that spectral analysis could serve as a valuable tool for practical purposes. An autoregressive moving-average spectral method is presented. It is based on the adaptive IIR filter and therefore provides both time and frequency information of the signal. The method has been applied to the running spectral analysis of the cutaneous EGG signals. The spectral analysis of the postprandial EGGs is presented.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115511426","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94953
R. Normann, P. K. Campbell, Wai Ping Li
The authors have produced a 0.4-mm*0.4-mm*1.6-mm, three-dimensional, silicon-based microstructure which can be used for stimulation of cortical neurons. The structure consists of 100 pyramidal-shaped needles, each 1.5 mm long with a base about 0.06 mm on a side. The entire structure is passivated with silicon nitride except for the tips of the needles, which are coated with platinum. The mechanical properties of these structures and the tissue reaction to them were studied in cat cortex. Impact insertion of the arrays produces good implantation with minimal tissue insult. Preliminary histological studies suggest that cortical tissues are not adversely affected by these microstructures.<>
{"title":"Silicon based microstructures suitable for intracortical electrical stimulation (visual prosthesis application)","authors":"R. Normann, P. K. Campbell, Wai Ping Li","doi":"10.1109/IEMBS.1988.94953","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94953","url":null,"abstract":"The authors have produced a 0.4-mm*0.4-mm*1.6-mm, three-dimensional, silicon-based microstructure which can be used for stimulation of cortical neurons. The structure consists of 100 pyramidal-shaped needles, each 1.5 mm long with a base about 0.06 mm on a side. The entire structure is passivated with silicon nitride except for the tips of the needles, which are coated with platinum. The mechanical properties of these structures and the tissue reaction to them were studied in cat cortex. Impact insertion of the arrays produces good implantation with minimal tissue insult. Preliminary histological studies suggest that cortical tissues are not adversely affected by these microstructures.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123349563","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 : 1988-11-01DOI: 10.1109/IEMBS.1988.94853
A. J. van den Bogert, A. Sauren, H. Schamhardt
An application of the DADS rigid-body package for analysis of locomotion in the horse is described. An important subject of study in equine locomotion research is the magnitude and distribution of forces inside the body, as it is generally assumed that overloading of joints, ligaments, and tendons is one of the main causes of acute and chronic injuries in equestrian sports. A biomechanical model of the horse has been developed to simulate the behavior of the musculoskeletal system under varying circumstances. The simulation software described was implemented on an Apollo DN4000 workstation using the DADS software package (version 5.0). Normal walking was simulated, using kinematic data for the proximal joints and tendon strain recordings from a normal walking pony as driving input for the model. Both movements and forces resemble observations in live animals. During the development of this model, much insight into the functioning of the locomotor system was gained. In particular, the role of polyarticular muscles and ligaments in the equine limbs was better understood.<>
{"title":"Analysis of locomotion in the horse using computer aided engineering software","authors":"A. J. van den Bogert, A. Sauren, H. Schamhardt","doi":"10.1109/IEMBS.1988.94853","DOIUrl":"https://doi.org/10.1109/IEMBS.1988.94853","url":null,"abstract":"An application of the DADS rigid-body package for analysis of locomotion in the horse is described. An important subject of study in equine locomotion research is the magnitude and distribution of forces inside the body, as it is generally assumed that overloading of joints, ligaments, and tendons is one of the main causes of acute and chronic injuries in equestrian sports. A biomechanical model of the horse has been developed to simulate the behavior of the musculoskeletal system under varying circumstances. The simulation software described was implemented on an Apollo DN4000 workstation using the DADS software package (version 5.0). Normal walking was simulated, using kinematic data for the proximal joints and tendon strain recordings from a normal walking pony as driving input for the model. Both movements and forces resemble observations in live animals. During the development of this model, much insight into the functioning of the locomotor system was gained. In particular, the role of polyarticular muscles and ligaments in the equine limbs was better understood.<<ETX>>","PeriodicalId":227170,"journal":{"name":"Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1988-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128268792","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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