| 1. |
- Ellenius, Johan, et al.
(author)
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Methods for selection of adequate neural network structures with application to early assessment of chest pain patients by biochemical monitoring
- 2000
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In: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 57:2-3, s. 181-202
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Journal article (peer-reviewed)abstract
- A methodology for selecting, training and estimating the performance of adequate artificial neural network (ANN) structures and incorporating them with algorithms that are optimized for clinical decision making is presented. The methodology was applied to the problem of early ruling-in/ruling-out of patients with suspected acute myocardial infarction using frequent biochemical monitoring. The selection of adequate ANN structures from a set of candidates was based on criteria for model compatibility, parameter identifiability and diagnostic performance. The candidate ANN structures evaluated were the single-layer perceptron (SLP), the fuzzified SLP, the multiple SLP, the gated multiple SLP, the multi-layer perceptron (MLP) and the discrete-time recursive neural network. The identifiability of the ANNs was assessed in terms of the conditioning of the Hessian of the objective function, and variability of parameter estimates and decision boundaries in the trials of leave-one-out cross-validation. The commonly used MLP was shown to be non-identifiable for the present problem and available amount of data, despite artificially reducing the model complexity with use of regularization methods. The investigation is concluded by recommending a number of guidelines in order to obtain an adequate ANN model.
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| 2. |
- Ellenius, Johan, et al.
(author)
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Transferability of neural network-based decision support algorithms for early assessment of chest-pain patients
- 2000
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In: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 60:1, s. 1-20
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Journal article (peer-reviewed)abstract
- The present investigation concerns methodological and epidemiological aspects of the transferability of artificial neural network-based algorithms, as key-components for classification in decision support systems (DSS). The prevalence of pathological conditions to be detected must be known in order to tune an artificial neural networks (ANN)-decision algorithm so that the predictive values of the outcome fulfil medical requirements. Another aspect of transferability, when clinical laboratory results are used, concerns differences in analytical performance of measuring instruments. The relative bias between two instruments is not known exactly, but must be estimated and corrected for. A general method, based on original measured data sets and statistical modeling, was developed for simulating the impact of various correction procedures when using different analytical instruments. The simulation methodology was applied to a real clinical problem of ruling-in/ruling-out of patients with suspected acute myocardial infarction (AMI) by biochemical monitoring. The recommended correction procedure was based on method comparison with use of five duplicate measurements on a common set of patient samples covering the relevant measuring interval. Transferability of laboratory data over time was also studied. The design of quality assurance procedures should be based on analytical quality requirement specifications related to medical needs. Limits of critically sized systematic errors were assessed by calculating the decrease in diagnostic performance of the ANN-algorithm as a result of temporary analytical disturbances. The consequences for the design of QA procedures was illustrated. It is concluded that the actual ANN-decision algorithm for early assessment of chest-pain patients should be possible to transfer to new sites under realistic conditions.
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| 3. |
- Franzén, Kristofer, et al.
(author)
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Protein names and how to find them
- 2002. - 1
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In: International Journal of Medical Informatics. - : Elsevier. - 1386-5056 .- 1872-8243. ; 67, s. 49-61
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Journal article (peer-reviewed)abstract
- A prerequisite for all higher level information extraction tasks is the identification of unknown names in text. Today, when large corpora can consist of billions of words, it is of utmost importance to develop accurate techniques for the automatic detection, extraction and categorization of named entities in these corpora. Although named entity recognition might be regarded a solved problem in some domains, it still poses a significant challenge in others. In this work we focus on one of the more difficult tasks, the identification of protein names in text. This task presents several interesting difficulties because of the named entities' variant structural characteristics, their sometimes unclear status as names, the lack of common standards and fixed nomenclatures, and the specifics of the texts in the molecular biology domain in which they appear. We describe how we approached these and other difficulties in the implementation of Yapex, a system for the automatic identification of protein names in text. We also evaluate Yapex under four different notions of correctness and compare its performance to that of another publicly available system for protein name recognition.
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| 4. |
- Lind, Leili, et al.
(author)
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Requirements and prototyping of a home health care application based on emerging JAVA technology.
- 2002
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In: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 68:1-3, s. 129-139
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Journal article (peer-reviewed)abstract
- IT support for home health care is an expanding area within health care IT development. Home health care differs from other in- or outpatient care delivery forms in a number of ways, and thus, the introduction of home health care applications must be based on a rigorous analysis of necessary requirements to secure safe and reliable health care. This article reports early experiences from the development of a home health care application based on emerging technologies. A prototype application for the follow-up of diabetes patients is presented and discussed in relation to a list of general requirements on home health care applications.
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| 5. |
- Nilsson, Gunnar, et al.
(author)
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Computerisation, coding, data retrieval and related attitudes among Swedish general practitioners - A survey of necessary conditions for a database of diseases and health problems
- 2002
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In: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 65:2, s. 135-143
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Journal article (peer-reviewed)abstract
- Objective: To investigate necessary conditions for the establishment of a database of diseases and health problems for research and health care planning, based on electronic patient records in everyday clinical use among general practitioners (GPs). Design: Postal questionnaire study. Setting: Primary health care in Sweden. Subjects: Three hundred randomly selected GPs. Main outcome measures: Degree of computerisation of patient records. User frequency and characteristics of diagnosis classification systems and coding tools. Frequency of coding activities and retrieval of codes, and related attitudes. Opinions on a primary health care version of ICD-10. Results: A total of 184 GPs (61% of the 300 GPs) were included in the study. About 92% used an electronic record system, some type of diagnostic classification was used by 93%, and ICD based classifications by 88%. The classification in use was computerised for 74%. Mainly simple tools were used to retrieve diagnostic codes. About 76% of GPs reported classifying at least one symptom or disease per encounter. The codes were retrieved 'once a month' or more by 19%. Classification of diseases was considered important for follow-up by 83%, and for the care of the patient by 75% of the GPs. The primary health care version of ICD-10 with a total of 972 codes was considered too limited in size by 31%. Conclusion: Electronic patient records in everyday clinical use in Swedish general practice provide several fundamentals for a database of diagnostic data. However, there are several barriers to the establishment of such a database that is both valid and reliable. ⌐ 2002 Elsevier Science Ireland Ltd. All rights reserved.
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| 6. |
- Qatarneh, Sharif M., et al.
(author)
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Evaluation of a segmentation procedure to delineate organs for use in construction of a radiation therapy planning atlas
- 2003
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In: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 69, s. 39-55
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Journal article (peer-reviewed)abstract
- Objectives: This paper evaluates a semi-automatic segmentation procedure to enhance utilizing atlas based treatment plans. For this application, it is crucial to provide a collection of 'reference' organs, restorable from the atlas so that they closely match those of the current patient. To enable assembling representative organs, we developed a semiautomatic procedure using an active contour method. Method: The 3D organ volume was identified by defining contours on individual slices. The initial organ contours were matched to patient volume data sets and then superimposed on them. These starting contours were then adjusted and refined to rapidly find the organ outline of the given patient. Performance was evaluated by contouring organs of different size, shape complexity, and proximity to surrounding structures. We used representative organs defined on CT volumes obtained from 12 patients and compared the resulting outlines to those drawn by a radiologist. Results: A strong correlation was found between the area measures of the delineated liver (r = 0.992), lung (r = 0.996) and spinal cord (r = 0.81), obtained by both segmentation techniques. A paired Student's t-test showed no statistical difference between the two techniques regarding the liver and spinal cord (p > 0.05). Conclusion: This method could be used to form 'standard' organs, which would form part of a whole body atlas (WBA) database for radiation treatment plans as well as to match atlas organs to new patient data.
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| 7. |
- Ölvingson, Christina, et al.
(author)
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Using the critical incident technique to define a minimal data set for requirements elicitation in public health
- 2002
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In: International Journal of Medical Informatics. - 1386-5056 .- 1872-8243. ; 68:1-3, s. 165-174
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Journal article (peer-reviewed)abstract
- The introduction of computer-based information systems (ISs) in public health provides enhanced possibilities for service improvements and hence also for improvement of the population's health. Not least, new communication systems can help in the socialization and integration process needed between the different professions and geographical regions. Therefore, development of ISs that truly support public health practices require that technical, cognitive, and social issues be taken into consideration. A notable problem is to capture ‘voices’ of all potential users, i.e., the viewpoints of different public health practitioners. Failing to capture these voices will result in inefficient or even useless systems. The aim of this study is to develop a minimal data set for capturing users' voices on problems experienced by public health professionals in their daily work and opinions about how these problems can be solved. The issues of concern thus captured can be used both as the basis for formulating the requirements of ISs for public health professionals and to create an understanding of the use context. Further, the data can help in directing the design to the features most important for the users.
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| 8. |
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| 9. |
- Andersson, Anna, et al.
(author)
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A Model for Interpreting Work and Information Management in Process-Oriented Healthcare Organisations
- 2003
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In: International Journal of Medical Informatics. - : Elsevier BV. - 1386-5056. ; 72:1-3, s. 47-56
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Journal article (peer-reviewed)abstract
- Background: To increase productivity, management in healthcare organisations have introduced different types of process-oriented organisational configurations. Few studies have addressed clinical practice and information management in these settings. Methods: A case study was performed at a paediatric clinic. Data was collected from archives, through interviews, by participatory observation, and by performing a focus group session. The collected data was analysed using a qualitative and interpretative research strategy. Results: A model was developed of care practitioners’ daily work in process-oriented organisations. The model shows that clinical work was deeply integrated; the care activities were dependent on supply activities and tightly connected to management routines. Conclusion: The resulting model can be used to support development of health information system (HIS) embedded in process-oriented healthcare work.
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| 10. |
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