Pub Date : 1996-10-31DOI: 10.1109/IEMBS.1996.646284
A. Feldman, Y. Chernyak, R. Cohen
The authors derive the curvature relation (the dependence of the wave speed on wavefront curvature) for a discrete model of an excitable medium allowing inhomogeneities in the limiting case of a medium with no recovery process. The model incorporates an element weighting distribution w that is varied locally to match the required values of the local plane wave speed, critical curvature, and effective diffusion constant. The authors successfully linked their discrete model to myocardium using valves obtained from the Luo-Rudy model.
{"title":"Speed-curvature relation for a discrete model of myocardium","authors":"A. Feldman, Y. Chernyak, R. Cohen","doi":"10.1109/IEMBS.1996.646284","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.646284","url":null,"abstract":"The authors derive the curvature relation (the dependence of the wave speed on wavefront curvature) for a discrete model of an excitable medium allowing inhomogeneities in the limiting case of a medium with no recovery process. The model incorporates an element weighting distribution w that is varied locally to match the required values of the local plane wave speed, critical curvature, and effective diffusion constant. The authors successfully linked their discrete model to myocardium using valves obtained from the Luo-Rudy model.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"9 1","pages":"1846-1847 vol.5"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72859633","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.651924
A. Klemt, A. Infantosi
For a microcomputer-based tutorial system, algorithms based on Surfaces have been implemented, using classification procedures for spatial position and normals of faces of anatomical structures, in order to establish a priori knowledge of visibility, distance and colouring. With the proposed approach reductions in computing time are always obtained, but the degree depends on the viewing angle. For a lateral-anterior view of the skull (31,873 faces), reductions of 33% were obtained in the number of read operations and 59% for visibility test.
{"title":"Surface classification method for a microcomputer-based tutorial system of anatomy","authors":"A. Klemt, A. Infantosi","doi":"10.1109/IEMBS.1996.651924","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.651924","url":null,"abstract":"For a microcomputer-based tutorial system, algorithms based on Surfaces have been implemented, using classification procedures for spatial position and normals of faces of anatomical structures, in order to establish a priori knowledge of visibility, distance and colouring. With the proposed approach reductions in computing time are always obtained, but the degree depends on the viewing angle. For a lateral-anterior view of the skull (31,873 faces), reductions of 33% were obtained in the number of read operations and 59% for visibility test.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"14 2 1","pages":"678-679 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76707735","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.656893
H. Journée, D. J. Hamoen, M. Staal, R. Sclabassi, R. Haaxma, A. Elands, J.J.J. Hummel
The objective of this work was to design and use a tremor recording and analysis system for stereotactic thalamotomy and thalamus stimulation (DBS). A notebook PC based system was developed. The tremor was measured by accelero-transducers or EMG. The method was used to confirm the definitive localization of the coagulation or stimulation target. Intra-operatively recorded effects of stimulation on the tremor were reproducible. Thermocoagulation and electrode implantation were done only after a significant reduction of the tremor was recorded on thalamic stimulation between 75 and 125 Hz. This method has been used on 9 patients: 2 underwent DBS implantation. It is concluded that intra-operative monitoring of the tremor during ventrolateral thalamotomy or stimulation is useful for identifying the final target for coagulation or electrode implantation.
{"title":"Tremor recording and analysis as a tool for target localisation in thalamotomy and DBS for tremor","authors":"H. Journée, D. J. Hamoen, M. Staal, R. Sclabassi, R. Haaxma, A. Elands, J.J.J. Hummel","doi":"10.1109/IEMBS.1996.656893","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.656893","url":null,"abstract":"The objective of this work was to design and use a tremor recording and analysis system for stereotactic thalamotomy and thalamus stimulation (DBS). A notebook PC based system was developed. The tremor was measured by accelero-transducers or EMG. The method was used to confirm the definitive localization of the coagulation or stimulation target. Intra-operatively recorded effects of stimulation on the tremor were reproducible. Thermocoagulation and electrode implantation were done only after a significant reduction of the tremor was recorded on thalamic stimulation between 75 and 125 Hz. This method has been used on 9 patients: 2 underwent DBS implantation. It is concluded that intra-operative monitoring of the tremor during ventrolateral thalamotomy or stimulation is useful for identifying the final target for coagulation or electrode implantation.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"35 1","pages":"154-156 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76782073","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.647562
M. Sugimachi, T. Kawada, Y. Ikeda, T. Yamazaki, K. Sunagawa
To characterize dynamic interaction between sympathetic and vagal heart rate control, the authors estimated linear transfer function from stimulation frequency to heart rate in the presence of various patterns of the stimulation of the other nerve. The gain of the transfer function increased by 80.7/spl plusmn/50.5% when 10 Hz tonic vagal stimulation accompanied white noise sympathetic stimulation. The gain was augmented by 24.1/spl plusmn/18.0% when 10 Hz tonic sympathetic stimulation accompanied white noise vagal stimulation. During simultaneous white noise stimulation, the gain was larger than that predicted by individual stimulation. The authors conclude that heart rate regulation is augmented bidirectionally and serves to enhance heart rate regulation under physiological conditions.
{"title":"Bidirectional augmentation of dynamic heart rate regulation by the autonomic nervous system","authors":"M. Sugimachi, T. Kawada, Y. Ikeda, T. Yamazaki, K. Sunagawa","doi":"10.1109/IEMBS.1996.647562","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.647562","url":null,"abstract":"To characterize dynamic interaction between sympathetic and vagal heart rate control, the authors estimated linear transfer function from stimulation frequency to heart rate in the presence of various patterns of the stimulation of the other nerve. The gain of the transfer function increased by 80.7/spl plusmn/50.5% when 10 Hz tonic vagal stimulation accompanied white noise sympathetic stimulation. The gain was augmented by 24.1/spl plusmn/18.0% when 10 Hz tonic sympathetic stimulation accompanied white noise vagal stimulation. During simultaneous white noise stimulation, the gain was larger than that predicted by individual stimulation. The authors conclude that heart rate regulation is augmented bidirectionally and serves to enhance heart rate regulation under physiological conditions.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"29 1","pages":"1584-1585 vol.4"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81745446","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.652747
D. Cavouras, P. Prassopoulos, Gregory Karangellis, M. Raissaki, L. Kostaridou, G. Panayiotakis
Differential diagnosis of hypodense liver lesions on CT is a common radiological problem. The aim of this study was to apply image analysis methods on non-enhanced CT images for discriminating small hemangiomas, the most common non-cystic benign lesion, from metastases, which represent the vast majority of malignant hepatic lesions. Twenty textural features were calculated from the CT density matrix of 20 hemangiomas and 36 liver metastases and were used to train a multilayer perceptron neural network classifier and four statistical classifiers. The neural network exhibited the highest classification accuracy (83.9%) employing 3 textural features (kurtosis, angular second moment, and inverse difference moment), 2 hidden layers and 4 hidden layer nodes. The diagnostic accuracy of CT in characterizing small hypodense liver lesions may be improved by the application of image analysis methods employing a multilayer neural network classifier.
{"title":"Application of a neural network and four statistical classifiers in characterizing small focal liver lesions on CT","authors":"D. Cavouras, P. Prassopoulos, Gregory Karangellis, M. Raissaki, L. Kostaridou, G. Panayiotakis","doi":"10.1109/IEMBS.1996.652747","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652747","url":null,"abstract":"Differential diagnosis of hypodense liver lesions on CT is a common radiological problem. The aim of this study was to apply image analysis methods on non-enhanced CT images for discriminating small hemangiomas, the most common non-cystic benign lesion, from metastases, which represent the vast majority of malignant hepatic lesions. Twenty textural features were calculated from the CT density matrix of 20 hemangiomas and 36 liver metastases and were used to train a multilayer perceptron neural network classifier and four statistical classifiers. The neural network exhibited the highest classification accuracy (83.9%) employing 3 textural features (kurtosis, angular second moment, and inverse difference moment), 2 hidden layers and 4 hidden layer nodes. The diagnostic accuracy of CT in characterizing small hypodense liver lesions may be improved by the application of image analysis methods employing a multilayer neural network classifier.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"17 1","pages":"1145-1146 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78683453","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.652798
J. Rogers, R. Ideker, W.M. Smith
Reentrant spiral waves propagating on curved surfaces lying in 3D space were modeled using a finite element solution of a modified FitzHugh-Nagumo system. Under some conditions, surface topology could induce drift of nominally stationary spirals, even in the absence of heterogeneity or anisotropy. These dynamics may be important in the maintenance of reentrant arrhythmias.
{"title":"Stability of spiral wave reentry on curved surfaces","authors":"J. Rogers, R. Ideker, W.M. Smith","doi":"10.1109/IEMBS.1996.652798","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652798","url":null,"abstract":"Reentrant spiral waves propagating on curved surfaces lying in 3D space were modeled using a finite element solution of a modified FitzHugh-Nagumo system. Under some conditions, surface topology could induce drift of nominally stationary spirals, even in the absence of heterogeneity or anisotropy. These dynamics may be important in the maintenance of reentrant arrhythmias.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"254 1","pages":"1254-1255 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78846892","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.651972
T. J. Noble, A. Morice, P. Milnes, N. Harris, A. Leathard, S. Smith, B. Brown
Our aim was to ascertain whether the Sheffield Mk.3a electrical impedance tomographic spectroscopy (EITS) system was able to reliably detect the presence of lung water. The patients studied were admitted with a diagnosis of left ventricular failure (LVF), a condition in which the quantity of lung water is significantly increased. This group was compared with a number of normal subjects. We were able to show that the conductance of the lung in patients with LVF was significantly higher than the normal group. This method may therefore have a role in the monitoring and diagnosis of left ventricular failure.
{"title":"Electrical impedance tomographic spectroscopy in the detection of increased lung water in heart failure","authors":"T. J. Noble, A. Morice, P. Milnes, N. Harris, A. Leathard, S. Smith, B. Brown","doi":"10.1109/IEMBS.1996.651972","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.651972","url":null,"abstract":"Our aim was to ascertain whether the Sheffield Mk.3a electrical impedance tomographic spectroscopy (EITS) system was able to reliably detect the presence of lung water. The patients studied were admitted with a diagnosis of left ventricular failure (LVF), a condition in which the quantity of lung water is significantly increased. This group was compared with a number of normal subjects. We were able to show that the conductance of the lung in patients with LVF was significantly higher than the normal group. This method may therefore have a role in the monitoring and diagnosis of left ventricular failure.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"88 1","pages":"778-779 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76332735","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.652724
D.W. Kim, S.C. Kim, S. J. Yoon, J.D. Lee, B. Kim
The hepatic extraction fraction (HEF), DISIDA-K, and ICG R/sub max/ were obtained to evaluate hepatic function for two normal and four abnormal rabbits with rapidly damaged livers. The correlation coefficients among these three methods were found. The correlation coefficient between the HEF and ICG R/sub max/ which is a standard technique in evaluating hepatic function was found to be 0.93. Therefore the HEF is assumed to be a valuable diagnostic method since it is not only accurate and simple, but possible to estimate remaining hepatic function after surgical removal of cancerous hepatic tissues.
{"title":"Quantitative evaluation of rabbit's hepatic function by HEF, DISADA-K, and ICG R/sub max/ methods","authors":"D.W. Kim, S.C. Kim, S. J. Yoon, J.D. Lee, B. Kim","doi":"10.1109/IEMBS.1996.652724","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.652724","url":null,"abstract":"The hepatic extraction fraction (HEF), DISIDA-K, and ICG R/sub max/ were obtained to evaluate hepatic function for two normal and four abnormal rabbits with rapidly damaged livers. The correlation coefficients among these three methods were found. The correlation coefficient between the HEF and ICG R/sub max/ which is a standard technique in evaluating hepatic function was found to be 0.93. Therefore the HEF is assumed to be a valuable diagnostic method since it is not only accurate and simple, but possible to estimate remaining hepatic function after surgical removal of cancerous hepatic tissues.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"73 1","pages":"1094-1095 vol.3"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76429391","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.646542
Ian T. Mcdougall, B. King, A. Hodgson
In cases of shoulder laxity or instability, physicians assess patients' humeral mobility by estimating the ranges of abduction and rotation over which the patient is pain-free. The present approach is quite subjective and shows poor intra- and inter-physician reliability. This paper describes a device we developed to accurately measure humeral orientation. The device does this by utilizing minimum constraint design to impose a consistent and repeatable axis of rotation on the shoulder joint which ensures that data from different patients assessed by different physicians can be reliably compared.
{"title":"A device for characterizing humeral orientation","authors":"Ian T. Mcdougall, B. King, A. Hodgson","doi":"10.1109/IEMBS.1996.646542","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.646542","url":null,"abstract":"In cases of shoulder laxity or instability, physicians assess patients' humeral mobility by estimating the ranges of abduction and rotation over which the patient is pain-free. The present approach is quite subjective and shows poor intra- and inter-physician reliability. This paper describes a device we developed to accurately measure humeral orientation. The device does this by utilizing minimum constraint design to impose a consistent and repeatable axis of rotation on the shoulder joint which ensures that data from different patients assessed by different physicians can be reliably compared.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"70 1","pages":"2297-2298 vol.5"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76212709","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 : 1996-10-31DOI: 10.1109/IEMBS.1996.647628
Kongjian An, Bai Jing, Zhou Xiaoqiang
A computer cardiovascular model has been developed to study the relationship between the cardiac function and the blood volume mathematically. Simulation results demonstrate that the quantity of the least blood volume, which is needed to maintain proper arterial blood pressures, depends heavily upon the degree of deterioration in heart failure. These results are in agreement with the clinical data and results reported in the literature. Simulation also suggests that a tradeoff might exist between cardiac energy consumption and cardiac material requirement during chronic heart failure compensation.
{"title":"The effects of hypervolemia on cardiac function. A computer simulation","authors":"Kongjian An, Bai Jing, Zhou Xiaoqiang","doi":"10.1109/IEMBS.1996.647628","DOIUrl":"https://doi.org/10.1109/IEMBS.1996.647628","url":null,"abstract":"A computer cardiovascular model has been developed to study the relationship between the cardiac function and the blood volume mathematically. Simulation results demonstrate that the quantity of the least blood volume, which is needed to maintain proper arterial blood pressures, depends heavily upon the degree of deterioration in heart failure. These results are in agreement with the clinical data and results reported in the literature. Simulation also suggests that a tradeoff might exist between cardiac energy consumption and cardiac material requirement during chronic heart failure compensation.","PeriodicalId":20427,"journal":{"name":"Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society","volume":"25 1","pages":"1717-1718 vol.4"},"PeriodicalIF":0.0,"publicationDate":"1996-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87504099","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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