T. Karson, S. Chandra, A. Morehead, S. Nissen, J.D. Thomas
The degree of information loss by compression of echocardiographic images utilizing the Joint Photographic Experts Group (JPEG) baseline system was evaluated using objective fidelity criteria. Standard echocardiograms were acquired digitally in real-time and stored on optical disk. 180 still frame images were processed in software using 5 preset quantization tables yielding average compression ratios of 7:1, 10:1, 17:1, 30:1 and 36:1. Objective parameters evaluated include the root mean square error (RMSE), signal-to-noise ratio (SNR), difference image mean and maximal pixel value shift. The mean pixel values and standard deviations of all images over all levels of compression were very similar. Even for ratios as high as 35:1, no significant bias was introduced in the pixel intensity values. Average RMSE ranged from 1.27 to 7.89 while average SNR ranged from 38.81 to 22.93. The data shows that JPEG compression at high ratios does not significantly alter objective image content and is a potential solution for reducing digital storage requirements.<>
{"title":"Digital compression of echocardiographic images: is it viable?","authors":"T. Karson, S. Chandra, A. Morehead, S. Nissen, J.D. Thomas","doi":"10.1109/CIC.1993.378356","DOIUrl":"https://doi.org/10.1109/CIC.1993.378356","url":null,"abstract":"The degree of information loss by compression of echocardiographic images utilizing the Joint Photographic Experts Group (JPEG) baseline system was evaluated using objective fidelity criteria. Standard echocardiograms were acquired digitally in real-time and stored on optical disk. 180 still frame images were processed in software using 5 preset quantization tables yielding average compression ratios of 7:1, 10:1, 17:1, 30:1 and 36:1. Objective parameters evaluated include the root mean square error (RMSE), signal-to-noise ratio (SNR), difference image mean and maximal pixel value shift. The mean pixel values and standard deviations of all images over all levels of compression were very similar. Even for ratios as high as 35:1, no significant bias was introduced in the pixel intensity values. Average RMSE ranged from 1.27 to 7.89 while average SNR ranged from 38.81 to 22.93. The data shows that JPEG compression at high ratios does not significantly alter objective image content and is a potential solution for reducing digital storage requirements.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"8 1","pages":"831-834"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82226928","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}
K. Akazawa, T. Uchiyama, S. Tanaka, A. Sasamori, E. Harasawa
Proposes a new adaptive method of data compression for digital ambulatory electrocardiograms (ECGs), considering the diagnostic significance of each segment of the ECG. The R-wave is detected, followed by multi-template matching of the detected beat and judgment of the noise level; the templates are successively created during processing. The residual signal (the difference between the original ECG and the best-fit template) is approximated with the FAN data compression method SAPA2 (Scan-Along Polygonal Approximation) and then encoded. The error threshold of FAN is decreased during the P-wave segments and increased during the noise segments; the maximum error of the reconstructed signal at each time is known. This method is applied to ECGs of the AHA (American Heart Association) database and its usefulness is indicated; e.g. the bit rate is approximately 400 bps at 8% PRD (percent RMS difference) and 200 bps at 15% PRD.<>
{"title":"Adaptive data compression of ambulatory ECG using multi templates","authors":"K. Akazawa, T. Uchiyama, S. Tanaka, A. Sasamori, E. Harasawa","doi":"10.1109/CIC.1993.378395","DOIUrl":"https://doi.org/10.1109/CIC.1993.378395","url":null,"abstract":"Proposes a new adaptive method of data compression for digital ambulatory electrocardiograms (ECGs), considering the diagnostic significance of each segment of the ECG. The R-wave is detected, followed by multi-template matching of the detected beat and judgment of the noise level; the templates are successively created during processing. The residual signal (the difference between the original ECG and the best-fit template) is approximated with the FAN data compression method SAPA2 (Scan-Along Polygonal Approximation) and then encoded. The error threshold of FAN is decreased during the P-wave segments and increased during the noise segments; the maximum error of the reconstructed signal at each time is known. This method is applied to ECGs of the AHA (American Heart Association) database and its usefulness is indicated; e.g. the bit rate is approximately 400 bps at 8% PRD (percent RMS difference) and 200 bps at 15% PRD.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"7 1","pages":"495-498"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85973940","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}
Spectral analysis of heart rate variability (HRV) has been tauted as a noninvasive means of assessing cardiac autonomic tone. Little agreement exists on optimal measures (i.e., peak vs. area absolute value vs. ratio, RR intervals vs. differences in successive RR intervals). The authors compared analyses of the first and last 128 beats of a 5 minute EKG acquisition in 81 healthy adults (age 21-65). It is concluded that: 1) most spectral indices of HRV are independent of resting heart rate; 2) the percent change between first and last segments showed no significant differences between any of the indices measured; 3) large short term changes in measures of HRV may limit their use for assessing changes in autonomic tone in individual subjects in response to physiologic stimuli such as tilt or standing.<>
{"title":"Short term reproducibility of indices of heart rate variability","authors":"M. Meaddens, T. Boyko, T. Vybiral, R. Bryg","doi":"10.1109/CIC.1993.378399","DOIUrl":"https://doi.org/10.1109/CIC.1993.378399","url":null,"abstract":"Spectral analysis of heart rate variability (HRV) has been tauted as a noninvasive means of assessing cardiac autonomic tone. Little agreement exists on optimal measures (i.e., peak vs. area absolute value vs. ratio, RR intervals vs. differences in successive RR intervals). The authors compared analyses of the first and last 128 beats of a 5 minute EKG acquisition in 81 healthy adults (age 21-65). It is concluded that: 1) most spectral indices of HRV are independent of resting heart rate; 2) the percent change between first and last segments showed no significant differences between any of the indices measured; 3) large short term changes in measures of HRV may limit their use for assessing changes in autonomic tone in individual subjects in response to physiologic stimuli such as tilt or standing.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"76 1","pages":"479-482"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86101869","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}
M. Varanini, A. Taddei, R. Balocchi, M. Macerata, F. Conforti, M. Emdin, C. Carpeggiani, C. Marchesi
The authors propose a method for artifact detection based on linear modelling of biological time series. An artifact, coming from a different "source", generally does not fit in the model and can be detected. Biological time series are not stationary, so that adaptive filtering is used for model estimation. Real time constraints warrant the use of predictive models only past input values are used to predict the current sample values. A set of thresholds or the prediction errors is used to detect artifacts. The authors model each time series by means of an adaptive prediction filter and, when a priori knowledge or the relation between two measurements, is available, they model this specific cross-channel relation with an adaptive filter. They applied this method to sequences of cardiovascular measurements from ICU and from Holter monitoring. The results obtained are fully satisfactory.<>
{"title":"Adaptive modelling of biological time series for artifact detection","authors":"M. Varanini, A. Taddei, R. Balocchi, M. Macerata, F. Conforti, M. Emdin, C. Carpeggiani, C. Marchesi","doi":"10.1109/CIC.1993.378307","DOIUrl":"https://doi.org/10.1109/CIC.1993.378307","url":null,"abstract":"The authors propose a method for artifact detection based on linear modelling of biological time series. An artifact, coming from a different \"source\", generally does not fit in the model and can be detected. Biological time series are not stationary, so that adaptive filtering is used for model estimation. Real time constraints warrant the use of predictive models only past input values are used to predict the current sample values. A set of thresholds or the prediction errors is used to detect artifacts. The authors model each time series by means of an adaptive prediction filter and, when a priori knowledge or the relation between two measurements, is available, they model this specific cross-channel relation with an adaptive filter. They applied this method to sequences of cardiovascular measurements from ICU and from Holter monitoring. The results obtained are fully satisfactory.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"74 1","pages":"695-698"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86317199","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}
T. Linderer, W. Wunderlich, F. Fischer, R. Schroder
The authors studied the effect various catheter sizes and floating image zoom on catheter calibrated vessel diameters. The pixel sizes of vessel phantoms (0.3-4.5 mm o) were obtained by optimum weighted edge detection. The 2.0 mm and the 3.0 mm phantom served as scaling device for catheter calibration. Image zoom varied from 1 to 6 fold. The authors found, that reference object calibration causes a rotation of measured native pixel diameter curves, whereby the amount of rotation depends on the size of the scaling catheter and affects especially diameters in the normal range of coronaries. It is concluded that using different catheter sizes and varying image zoom should be discouraged in long-term studies of coronary artery disease, since they feign non-existent lesion changes.<>
研究了不同导管尺寸和浮动图像变焦对导管标定血管直径的影响。通过最优加权边缘检测，获得了血管影的像素大小(0.3 ~ 4.5 mm o)。2.0 mm和3.0 mm幻影作为导管校准的刻度装置。图像变焦从1到6倍不等。作者发现，参考对象校准引起测量的原生像素直径曲线的旋转，其中旋转的量取决于缩放导管的大小，特别是影响冠状动脉正常范围内的直径。因此，在冠状动脉疾病的长期研究中，不建议使用不同尺寸的导管和不同的图像变焦，因为它们会伪造不存在的病变改变
{"title":"Quantitative coronary arteriography: the impact of image zoom and reference object size on diameter measurements","authors":"T. Linderer, W. Wunderlich, F. Fischer, R. Schroder","doi":"10.1109/CIC.1993.378336","DOIUrl":"https://doi.org/10.1109/CIC.1993.378336","url":null,"abstract":"The authors studied the effect various catheter sizes and floating image zoom on catheter calibrated vessel diameters. The pixel sizes of vessel phantoms (0.3-4.5 mm o) were obtained by optimum weighted edge detection. The 2.0 mm and the 3.0 mm phantom served as scaling device for catheter calibration. Image zoom varied from 1 to 6 fold. The authors found, that reference object calibration causes a rotation of measured native pixel diameter curves, whereby the amount of rotation depends on the size of the scaling catheter and affects especially diameters in the normal range of coronaries. It is concluded that using different catheter sizes and varying image zoom should be discouraged in long-term studies of coronary artery disease, since they feign non-existent lesion changes.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"121 1","pages":"579-582"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85968015","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}
Wigner Ville distribution has many of the desirable features for the spectral analysis of cardiovascular series during the transients of the autonomic tests, but the presence of the artefacts makes power measurements from the spectra often unreliable. This work proposes new approaches for rejecting artefacts, besides the well known spectral averaging. In particular, an appropriate preprocessing and a segment-regression based smoothing are considered and compared with the classical approach, taking into account both the different characteristics of the considered autonomic tests.<>
{"title":"Artefact rejection from Wigner Ville spectra of cardiovascular series in autonomic tests","authors":"S. Pola, M. Emdin, A. Macerata, C. Marchesi","doi":"10.1109/CIC.1993.378361","DOIUrl":"https://doi.org/10.1109/CIC.1993.378361","url":null,"abstract":"Wigner Ville distribution has many of the desirable features for the spectral analysis of cardiovascular series during the transients of the autonomic tests, but the presence of the artefacts makes power measurements from the spectra often unreliable. This work proposes new approaches for rejecting artefacts, besides the well known spectral averaging. In particular, an appropriate preprocessing and a segment-regression based smoothing are considered and compared with the classical approach, taking into account both the different characteristics of the considered autonomic tests.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"5 1","pages":"811-814"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78626907","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}
The author investigates the differences in the correlation dimension (D/sub 2/) measured from electrocardiograms (ECG) of normal and sick subjects obtained from the MIT-BIH Arrhythmia Database. It is observed that there is a greater variability in the dynamics of the system underlying the ECGs recorded from pathological subjects than from normals. A particular attention to make results repeatable is paid.<>
{"title":"Differences on the correlation dimension of MIT-BIH ECG database recordings","authors":"A. Casaleggio","doi":"10.1109/CIC.1993.378383","DOIUrl":"https://doi.org/10.1109/CIC.1993.378383","url":null,"abstract":"The author investigates the differences in the correlation dimension (D/sub 2/) measured from electrocardiograms (ECG) of normal and sick subjects obtained from the MIT-BIH Arrhythmia Database. It is observed that there is a greater variability in the dynamics of the system underlying the ECGs recorded from pathological subjects than from normals. A particular attention to make results repeatable is paid.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"115 1","pages":"539-542"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77912283","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}
S. Caswell, K.S. Kluge, C. Chiang, J. Jenkins, L. DiCarlo
New techniques of arrhythmia detection using morphology of the waveform have shown promise in correctly detecting fatal arrhythmias. Morphologic analysis of two channels, atrial and ventricular, has the potential of improving the ability of the algorithm to distinguish arrhythmias. This study uses correlation waveform analysis of intracardiac electrograms from the right ventricular apex and the high right atrium to define a two dimensional feature space with linear decision boundaries created from a training set by a least squares minimum distance classifier. The total set represented 16 patients. This method correctly discriminated 48/48 cycles of sinus rhythm, 47/48 of ventricular tachycardia (VT), 39/48 of atrial tachycardia and 40/48 of VT with retrograde, and supraventricular tachycardia with aberrant conduction. Performing this technique on two intracardiac electrograms appears to reliably differentiate various arrhythmias and warrants further study.<>
{"title":"Pattern recognition of cardiac arrhythmias using two intracardiac channels","authors":"S. Caswell, K.S. Kluge, C. Chiang, J. Jenkins, L. DiCarlo","doi":"10.1109/CIC.1993.378474","DOIUrl":"https://doi.org/10.1109/CIC.1993.378474","url":null,"abstract":"New techniques of arrhythmia detection using morphology of the waveform have shown promise in correctly detecting fatal arrhythmias. Morphologic analysis of two channels, atrial and ventricular, has the potential of improving the ability of the algorithm to distinguish arrhythmias. This study uses correlation waveform analysis of intracardiac electrograms from the right ventricular apex and the high right atrium to define a two dimensional feature space with linear decision boundaries created from a training set by a least squares minimum distance classifier. The total set represented 16 patients. This method correctly discriminated 48/48 cycles of sinus rhythm, 47/48 of ventricular tachycardia (VT), 39/48 of atrial tachycardia and 40/48 of VT with retrograde, and supraventricular tachycardia with aberrant conduction. Performing this technique on two intracardiac electrograms appears to reliably differentiate various arrhythmias and warrants further study.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"27 1","pages":"181-184"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75272416","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}
S. Khoor, F. Szaboki, J. Nieberl, M. Khoor, E. Kékes
The authors' automated image processing method creates the velocity maps of the small regions of echocardiographic 2D images. The separation and matching of this objects are based on their velocity profiles. The object-oriented programming method allows the handling such a complex problem. The automated analysis showed a good performance comparing with the traditional wall motion detection: the specificity of computer scoring was 84.4%, the sensitivity 81.2%.<>
{"title":"A new method of echocardiographic edge detection using velocity maps","authors":"S. Khoor, F. Szaboki, J. Nieberl, M. Khoor, E. Kékes","doi":"10.1109/CIC.1993.378325","DOIUrl":"https://doi.org/10.1109/CIC.1993.378325","url":null,"abstract":"The authors' automated image processing method creates the velocity maps of the small regions of echocardiographic 2D images. The separation and matching of this objects are based on their velocity profiles. The object-oriented programming method allows the handling such a complex problem. The automated analysis showed a good performance comparing with the traditional wall motion detection: the specificity of computer scoring was 84.4%, the sensitivity 81.2%.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"59 1","pages":"623-626"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75994920","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}
The surface detection of delayed fragmented waveforms-ventricular late potentials-continuous with the end of the QRS complex during sinus rhythm in post-myocardial infarction subjects has been considered as a noninvasive risk indicator for the possible development of sustained ventricular tachycardia. In this paper, bispectral analysis (using nonparametric techniques) of synthesized ECG data containing late potentials characterised by Simson's (1981) method are used to identify late signal components terminal in the QRS. The bispectrum estimation technique is shown to offer an advantage over the conventional power spectra in that it represents the true phase characteristics produced by the nonlinear electrical excitation of the heart. Additionally, forming the bispectrum of the data set automatically suppressed any Gaussian signal components (the original measurement noise was modelled as being Gaussian in nature), and consequently resulted in automatic noise reduction.<>
{"title":"Bispectral analysis for the detection of ventricular late potentials","authors":"C. Speirs, J. Soraghan, R. Stewart, M. Polson","doi":"10.1109/CIC.1993.378412","DOIUrl":"https://doi.org/10.1109/CIC.1993.378412","url":null,"abstract":"The surface detection of delayed fragmented waveforms-ventricular late potentials-continuous with the end of the QRS complex during sinus rhythm in post-myocardial infarction subjects has been considered as a noninvasive risk indicator for the possible development of sustained ventricular tachycardia. In this paper, bispectral analysis (using nonparametric techniques) of synthesized ECG data containing late potentials characterised by Simson's (1981) method are used to identify late signal components terminal in the QRS. The bispectrum estimation technique is shown to offer an advantage over the conventional power spectra in that it represents the true phase characteristics produced by the nonlinear electrical excitation of the heart. Additionally, forming the bispectrum of the data set automatically suppressed any Gaussian signal components (the original measurement noise was modelled as being Gaussian in nature), and consequently resulted in automatic noise reduction.<<ETX>>","PeriodicalId":20445,"journal":{"name":"Proceedings of Computers in Cardiology Conference","volume":"17 1","pages":"427-430"},"PeriodicalIF":0.0,"publicationDate":"1993-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75341507","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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