bluuebunny/crossref_metadata_2025_split huggingface dataset:
Classification Methods for Computerized Interpretation of the Electrocardiogram
Authors: Kors J. A. , van Bemmel J. H. 
Published: March 2018

AbstractTwo methods for diagnostic classification of the electrocardiogram are described: a heuristic one and a statistical one. In the heuristic approach, the cardiologist provides the knowledge to construct a classifier, usually a decision tree. In the statistical approach, probability densities of diagnostic features are estimated from a learning set of ECGs and multivariate techniques are used to attain diagnostic classification. The relative merits of both approaches with respect to criteria selection, comprehensibility, flexibility, combined diseases, and performance are described. Optimization of heuristic classifiers is discussed. It is concluded that heuristic classifiers are more comprehensible than statistical ones; encounter less difficulties in dealing with combined categories; are flexible in the sense that new categories may readily be added or that existing ones may be refined stepwise. Statistical classifiers, on the other hand, are more easily adapted to another operating environment and require less involvement of cardiologists. Further research is needed to establish differences in performance between both methods. In relation to performance testing the issue is raised whether the ECG should be classified using as much prior information as possible, or whether it should be classified on itself, explicitly discarding information other than age and sex, while only afterwards other information will be used to reach a final diagnosis. Consequences of taking one of both positions are discussed.
Common Standards for Quantitative Electrocardiography: Goals and Main Results
Authors: Arnaud P. , van Bemmel J. H. , Degani R. , Macfarlane P. W. , Zywietz Chr. , Willems J. L. ,   for the CSE Working Party
Published: March 2018

AbstractComputer processing of electrocardiograms (ECGs) has over the last 15 years increased rapidly. Still, there are at present no standards for computer ECG interpretation. Different techniques are used not only for measurement and interpretation, but also for transmission and storage of data. In order to fill these gaps, a large international project, sponsored by the European Commission, was launched in 1980 to develop “Common Standards for Quantitative Electrocardiography (CSE)”. The main objective of the first CSE study was to reduce the wide variation in wave measurements currently obtained by ECG computer programs. The second study was started in 1985 and aimed at the assessment and improvement of diagnostic classification of ECG interpretation programs. To this end reference libraries of well documented ECGs have been developed and comprehensive reviewing schemes devised for the visual and computer analysis of ECGs. This task was performed by a board of cardiologists in a Delphi review process, and by 9 VCG and 10 standard 12-lead programs developed by university research groups and by industry. A third action was started in June 1989 to harmonize acquisition, encoding, interchange and storing of digital ECG data. The action thus performed have become internationally recognized milestones for the standardization of quantitative electrocardiography.
Evaluation of ECG Interpretation Results Obtained by Computer and Cardiologists
Authors: Abreu-Lima C. , Arnaud P. , Brohet C. R. , Denis B. , Gehring J. , Graham I. , van Herpen G. , Machado H. , Michaelis J. , Moulopoulos S. D. , Willems J. L. 
Published: March 2018

AbstractIn an international project investigators from 25 institutes are trying to establish a common reference library and evaluation methods for testing the diagnostic performance of various ECG computer programs and of cardiologists, based on ECG-independent clinical information. A first set of 500 validated ECGs was collected and analyzed by fifteen different computer programs and nine cardiologists, seven of who analysed the ECG and five the VCG. A coding scheme was used to map individual diagnostic statements onto a common set. Combined program and referee results were obtained by weighted averaging. Preliminary results indicate that the classification accuracy of several programs can still be improved. However, it was also apparent that the results of the best 12-lead ECG computer programs proved to be almost as accurate as the best of seven cardiologists in classifying seven main disease categories, i.e., normal, left, right and biventricular hypertrophy, anterior, inferior and combined myocardial infarction. Evaluation of rhythm statements and conduction disturbances was not included in the study. The data collection is still being pursued in order to reach over 1,000 cases. In this way a common diagnostic database is being established for comparative testing of diagnostic computer programs. This should lead to consumer protection and improve the accuracy and reliability of computerized electrocardiography.
Evaluation of ECG Interpretation Systems: Signal Analysis
Authors: Zywietz Chr. , van Bemmel J. H. , Degani R. 
Published: March 2018

AbstractPerformance analysis of biosignal processing systems which provide diagnostic statements requires particular care. Besides general accuracy requirements, psychological and legal implications for patient and physician have to be considered on both the development and the user sites. Cybernetics and control engineering have provided the basic methodology for performance analysis of systems: in technical systems often mathematically defined functions and signals can be fed into the system to be tested and its response and output provide the necessary performance characteristics after adequate mathematical analysis. For systems which process biosignals, as for example ECG analysis systems, instead of analytically given signals learning and test sets of data derived from patients have to be applied. The performance analysis is done on a statistical basis. In this paper construction and composition of learning and test data sets as well as methods for performance evaluation of the signal pocessing part of ECG programs are described. Specific reference is made to the European project Common Standards for Quantitative Electrocardiography (CSE) where ten ECG- and nine VCG-programs have been tested. The results of these tests provide reference data and standards for further program development as well as for independent system performance evaluation.
Methodology of ECG Interpretation in the AVA Program
Authors: Pipberger H. A. , Pipberger H. V. , McManus C. D. 
Published: March 2018

AbstractThe AVA program combines a thirty-year history with an approach that remains innovative; namely: multivariate statistical analysis on orthogonal ECG leads. Its diagnostic reference base includes only diagnoses independently verified by non-ECG criteria. The diagnostic module assesses probabilities of nine alternative disease categories, based on QRS-T parameters; or four other categories in case of conduction defects. Probabilities of left or right atrial overload are also computed. The program also recognizes wall injury, T-wave abnormalities, electrolyte disturbances, myocardial ischemia, and makes differential diagnoses between strain and digitalis effects. An arrhythmia classification module can generate any of 40 rhythm statements. Signal recognition is based on the spatial velocity function. The program has been translated to a microcomputer version.
Methodology of ECG Interpretation in the Dalhousie Program; NOVACODE ECG Classification Procedures for Clinical Trials and Population Health Surveys
Authors: Rautaharju P. M. , MacInnis P. J. , Warren J. W. , Wolf H. K. , Rykers P. M. , Calhoun H. P. 
Published: March 2018

AbstractThe Dalhousie ECG Program was designed specifically for the needs of epidemiologic studies, health surveys, and clinical trials. The program logic is dynamic in that it can accommodate any combination of ECG leads, record length and sampling rate. The NOVACODE module of the program classifies ECGs according to the Minnesota Code, supplemented with new sets of logic criteria for conduction defects, acute myocardial infarction, and serial ECG changes. Improved statistical models are incorporated for enhanced detection of myocardial infarction using the Cardiac Infarction Injury Score, and for quantification of left ventricular mass estimation. It is anticipated that these program improvements will enhance its utility particularly in monitoring progression and regression of cardiac involvement in hypertensive and ischemic heart disease, and in the assessment of the effectiveness of intervention on cardiovascular disease risk factors.
Methodology of ECG Interpretation in the Hannover Program
Authors: Borovsky D. , Gotsch G. , Joseph G. , Zywietz Chr. 
Published: March 2018

AbstractThe Hannover ECG program HES has been designed for measurement and interpretation of resting and (moderate) exercise electrocardiograms. In the signal analysis part the program follows an averaging strategy. For diagnostic classification a hybrid model with decision trees and scoring algorithms, and with multivariate probabilistic tests for derivation of category A statements is applied. The multivariate classification technique allows to adjust sensitivity and specificity for specific application areas without changing the diagnostic criteria.
Methodology of ECG Interpretation in the Lyon Program
Authors: Morlet D. , Fayn J. , Forlini M.C. , Arnaud P. , Rubel P. 
Published: March 2018

AbstractTo provide an in-depth interpretation of the spatial QRS-T contour, we established a set of vectorcardiographic parameters computed octant by octant. For each statement the criteria constitute a model which is closely related to pathophysiological patterns. The diagnostic strategy is of the heuristic type. For each diagnosis a table lists several criteria providing both specific and differential diagnostic information. Inter-table competition is handled by specific logic. The program classifies diagnoses according to the number of non-satisfied criteria. Three versions are available including 124,51 and 7 diagnoses, respectively. The first, intended for interpretation of complex situations, has given satisfactory results in such situations. Rhythm analysis is performed from 8-second recordings.All functions - acquisition, quality control, choice of a dominant complex, wave recognition, parameter extraction, interpretation, editing, storage -are integrated into a mobile cart. A complementary program performs serial analysis of successive tracings. It highlights with great precision morphological changes in the spatial loops and interval variations.
Methodology of the Modular ECG Analysis System MEANS
Authors: van Herpen G. , van Bemmel J. H. , Kors J. A. 
Published: March 2018

AbstractThe methodology, used in the Modular ECG Analysis System (MEANS) is described. MEANS consists of modules for signal analysis and diagnostic classification. The basic structure of the modular interpretation system remained intact over a period of 20 years, while all modules underwent many changes as a function of experience and insight, and the continuously changing information technology. The article describes the advantages of a modular approach to decision-support systems, the most important ones being easier maintenance of the software package and separate optimization and testing of each module. The overall evaluation of MEANS was done in the CSE study. Evaluation results for modules and for the entire system are presented.
Reference Standards for Software Evaluation
Authors: Wellek S. , Willems J. L. , Michaelis J. 
Published: March 2018

AbstractThe field of automated ECG analysis was one of the earliest topics in Medical Informatics and may be regarded as a model both for computer-assisted medical diagnosis and for evaluating medical diagnostic programs. The CSE project has set reference standards of two kinds: In a broad sense, a standard how to perform a comprehensive evaluation study, in a narrow sense, standards as specific references for evaluating computer ECG programs. The evaluation methodology used within the CSE project is described as a basis for presentation of results which are published elsewhere in this issue.
Value of Scatter-Graphs for the Assessment of ECG Computer Measurement Results
Authors: Rubel P. , Willems J. L. , Morlet D. 
Published: March 2018

AbstractA new method is presented, different from usual methods, for the discussion of the results of computer ECG measurement programs, based on a new graphical evaluation method. The proposed “scatter-graphs” both highlight the main program results and facilitate the comparison between various wave-recognition algorithms. They allow the distinction between the reliability of an algorithm, which is its capacity to provide a maximum of measurements with a minimum amount of errors, and its precision, i.e., the standard deviation of the differences between its point estimates and the reference.The method proves to be a powerful tool for the discussion of individual, as well as the median program results in CSE Measurement Study. It allows to highlight limitations induced in performance assessment by the variability of the reference itself, and to state that the median program is at least as close to the “Gold Standard” as the median of the referees.
Toward Normative Expert Systems: Part II Probability-Based Representations for Efficient Knowledge Acquisition and Inference
Authors: Heckerman E. D. , Nathwani N. B. 
Published: March 2018

Abstract:We address practical issues concerning the construction and use of decision-theoretic or normative expert systems for diagnosis. In particular, we examine Pathfinder, a normative expert system that assists surgical pathologists with the diagnosis of lymph-node diseases, and discuss the representation of dependencies among pieces of evidence within this system. We describe the belief network, a graphical representation of probabilistic dependencies. We see how Pathfinder uses a belief network to construct differential diagnosis efficiently, even when there are dependencies among pieces of evidence. In addition, we introduce an extension of the belief-network representation called a similarity network, a tool for constructing large and complex belief networks. The representation allows a user to construct independent belief networks for subsets of a given domain. A valid belief network for the entire domain can then be constructed from the individual belief networks. We also introduce the partition, a graphical representation that facilitates the assessment of probabilities associated with a belief network. We show that the similarity-network and partition representations made practical the construction of Pathfinder.
Use of Two Online Services as Drug Information Sources for Health Professionals
Authors: Shumwayb J. M. , Jacknowitzc A. I. , Abatea M. A. 
Published: March 2018

Abstract:The utility of the online computer services BRS Colleague and Dialog Medical Connection, when used primarily as drug information sources by physicians, nurses, and pharmacists and attitudes toward their use, are described. Study sites included office-based medical practices, a university clinic family medicine group, and a university clinical pharmacy department. Participants had access to either of the computer services during two 9½-month periods. All searches were automatically recorded and analyzed. A total of 1,112 search sessions were conducted (78% by pharmacists, 16% by nurses, 6% by physicians) by 38 of 65 participants. Information which completely answered questions was found for slightly less than one-third of searches. Errors occurred in about 81% of searches which retrieved incomplete information. Lack of time was a major factor which limited use of the services, and infrequent users felt that the services did not fit in well with their daily work routine.
Graphical Access to Medical Expert Systems: V. Integration with Continuous-Speech Recognition
Authors: Wulfman C. E. , Rua M. , Lane C. D. , Shortliffe E. H. , Fagan L. M. 
Published: March 2018

Abstract:This paper describes three prototypes of computer-based clinical record-keeping tools that use a combination of window-based graphics and continuous speech in their user interfaces. Although many of today’s commercial speech-recognition products achieve high rates of accuracy for large grammars (vocabularies of words or collections of sentences and phrases), they can only “listen for” (and therefore recognize) a limited number of words or phrases at a time. When a speech application requires a grammar whose size exceeds a speech-recognition product’s limits, the application designer must partition the large grammar into several smaller ones and develop control mechanisms that permit users to select the grammar that contains the words or phrases they wish to utter. Furthermore, the user interfaces they design must provide feedback mechanisms that show users the scope of the selected grammars. The three prototypes described were designed to explore the use of window-based graphics as control and feedback mechanisms for continuous-speech recognition in medical applications. Our experiments indicate that window-based graphics can be effectively used to provide control and feedback for certain classes of speech applications, but they suggest that the techniques we describe will not suffice for applications whose grammars are very complex.
MultiLink – An Intermediary System for Multi-Database Access
Authors: Wu G. , Åhlfeldt H. , Wigertz O. 
Published: March 2018

Abstract:The design and implementation is described of MultiLink, a desktop system for direct enduser access to remote bibliographic information. The system is an application of a client-server technique based on a campuswide network, with the objective to assist end-users to accomplish the information — retrieval process by capturing knowledge and expertise for searches in query formulations. MultiLink, via intelligent interfaces, allows users to access several dozens of bibliographic databases. The application integrates regional, national and international resources, and brings library services to the user’s desktop level.
Evaluating Consensus Among Physicians in Medical Knowledge Base Construction
Authors: Giuse D. A. , MMer R. A. , Bankowitz R. A. , Janosky J. E. , Davidoff F. , Hillner B. E. , Hripcsak G. , Lincoln M. J. , Middleton B. , Peden J. G. , Giuse N. B. 
Published: March 2018

Abstract:This study evaluates inter-author variability in knowledge base construction. Seven board-certified internists independently profiled “acute perinephric abscess”, using as reference material a set of 109 peer-reviewed articles. Each participant created a list of findings associated with the disease, estimated the predictive value and sensitivity of each finding, and assessed the pertinence of each article for making each judgment. Agreement in finding selection was significantly different from chance: seven, six, and five participants selected the same finding 78.6, 9.8, and 1.6 times more often than predicted by chance. Findings with the highest sensitivity were most likely to be included by all participants. The selection of supporting evidence from the medical literature was significantly related to each physician’s agreement with the majority. The study shows that, with appropriate guidance, physicians can reproducibly extract information from the medical literature, and thus established a foundation for multi-author knowledge base construction.
A Modular Knowledge Base for the Follow-Up of Clinical Protocols
Authors: Otero R. P. , Marín R. , Mira J. , Barreiro A. 
Published: March 2018

AbstractFrom the knowledge engineering point of view, the observation of patients subjected to clinical protocols of therapy constitutes a domain characterized by the existence of strongly structured knowledge. We have approached the problem from the perspective of a homogeneous and modular knowledge representation theory, based on the concept of Generalized Magnitude. This concept arises from identifying and collecting all possible facts of a domain established a priori, and being inspired by the concept of physical magnitudes. The Generalized Magnitudes scheme includes temporal extensions necessary to solve a medical problem for which exists a therapy and a follow-up plan with temporal specifications, and also facilitates the creation of advisory expert systems.
Influence of “Outliers” on the Association between Laboratory Data and Histopathological Findings in Liver Biopsy
Authors: Krusinska E. , Mathiesen U. L. , Franzén L. , Bodemar G. , Wigertz O. 
Published: March 2018

AbstractDiscriminant analysis techniques were used to predict the histopathological findings in liver biopsy specimens in asymptomatic patients with slightly to moderately raised routine liver tests. Moderate to severe fibrosis and/or inflammation were treated as indication for biopsy. Two methods were used to classify patients. One was the dichotomous discrimination between “biopsy necessary” or “biopsy not necessary” groups of patients. The other involved combining two discriminant functions trained separately for recognition of fibrosis or inflammation, and then combined to predict the biopsy necessity. Detection of outliers by standard techniques, directly available in the SPSS-X package, was performed before starting discrimination procedures. Both “sharp” assignment rules and continuous scoring rules were applied to the classification problem. The correct classification rate reached over 85% for the algorithms tested. In the majority of cases the classification was found to be “non-doubtful”. Elimination of outliers (especially by standardized residuals) improved the global correct classification rate, but only slightly improved assignment to the “biopsy necessary” group. Routine and complementary laboratory findings were found to be the most discriminating; answers to questionnaire and ultrasound examination were less important. Selection of the most diagnostic features based on “clean” data without outliers enabled us to find interesting medical associations, which were previously masked by extremely asymptomatic values outlying from the main body of the “biopsy necessary” group.