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  • 301.
    Karlsson, Anette
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Linge, Jennifer
    Advanced MR Analytics AB.
    West, Janne
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Bell, Jimmy
    Westminster University, London, UK.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Defining Sarcopenia with MRI - Establishing Threshold Values within a Large-Scale Population Study2016Conference paper (Other academic)
    Abstract [en]

    PURPOSE

    To identify gender specific threshold values for sarcopenia detection for lean thigh muscle tissue volume quantified using MRI.

    METHOD AND MATERIALS

    Current gender-specific thresholds for sarcopenia detection are based on quantification on appendicular lean tissue normalized with height^2 using DXA (7.26 kg/m2 for men and 5.45 kg/m2 for women). In this study 3514 subjects (1548 males and 1966 females) in the imaging subcohort of UK Biobank with paired DXA and MRI scans were included. The age range was 45 to 78 years. The total lean thigh volume normalized with height2 (TTVi) was determined with a 6 minutes neck to knee 2-point Dixon MRI protocol using a 1.5T MR-scanner (Siemens, Germany) followed by analysis with AMRA® Profiler (AMRA, Sweden). The appendicular lean tissue mass normalized with height2 (ALTMi) was assessed using DXA (GE-Lunar iDXA). Subjects with ALTMi lower than the gender specific threshold were categorized as sarcopenic. Gender specific threshold values were determined for detection of sarcopenic subjects based on TTVi optimizing sensitivity and specificity. Area under receiver operator curve (AUROC) was calculated as well as the linear correlation between TTVi and ALTMi.

    RESULTS

    A threshold value of TTVi = 3.64 l/m2 provided a sensitivity and specificity of 0.88 for sarcopenia detection in males. The AUROC was 0.96. Similarly, a TTVi < 2.76 l/m2 identified sarcopenic female subjects with a sensitivity and specificity of 0.89. The corresponding AUROC was 0.96. The linear correlation between TTVi and ALTMi was 0.93 (99%CI: 0.93-0.94).

    CONCLUSION

    MRI-based quantification of total lean thigh volume normalized with height^2 could be used to categorize sarcopenia in the study group. Threshold values are suggested.

    CLINICAL RELEVANCE/APPLICATION

    The study suggests that sarcopenia can be diagnosed using a rapid MRI scan with high sensitivity and specificity.

  • 302.
    Karlsson, Anette
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Rosander, Johannes
    Advanced MR Analytics AB, Linköping, Sweden.
    Romu, Thobias
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Tallberg, Joakim
    Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Grönqvist, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Automatic and quantitative assessment of regional muscle volume by multi-atlas segmentation using whole-body water–fat MRI2015In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 41, no 6, p. 1558-1569Article in journal (Refereed)
    Abstract [en]

    Purpose

    To develop and demonstrate a rapid whole-body magnetic resonance imaging (MRI) method for automatic quantification of total and regional skeletal muscle volume.

    Materials and Methods

    The method was based on a multi-atlas segmentation of intensity corrected water–fat separated image volumes. Automatic lean muscle tissue segmentations were achieved by nonrigid registration of atlas datasets with 10 different manually segmented muscle groups. Ten subjects scanned at 1.5 T and 3.0 T were used as atlases, initial validation and optimization. Further validation used 11 subjects scanned at 3.0 T. The automated and manual segmentations were compared using intraclass correlation, true positive volume fractions, and delta volumes.

    Results

    For the 1.5 T datasets, the intraclass correlation, true positive volume fractions (mean ± standard deviation, SD), and delta volumes (mean ± SD) were 0.99, 0.91 ± 0.02, −0.10 ± 0.70L (whole body), 0.99, 0.93 ± 0.02, 0.01 ± 0.07L (left anterior thigh), and 0.98, 0.80 ± 0.07, −0.08 ± 0.15L (left abdomen). The corresponding values at 3.0 T were 0.97, 0.92 ± 0.03, −0.17 ± 1.37L (whole body), 0.99, 0.93 ± 0.03, 0.03 ± 0.08L (left anterior thigh), and 0.89, 0.90 ± 0.04, −0.03 ± 0.42L (left abdomen). The validation datasets showed similar results.

    Conclusion

    The method accurately quantified the whole-body skeletal muscle volume and the volume of separate muscle groups independent of field strength and image resolution. 

  • 303.
    Karlsson, Anette
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Rosander, Johannes
    Advanced MR Analytics AB, Linköping, Sweden.
    Romu, Thobias
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Tallberg, Joakim
    Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Grönqvist, Anders
    Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Automatic and Quantitative Assessment of Total and Regional Muscle Tissue Volume using Multi-Atlas Segmentation2014Conference paper (Other academic)
    Abstract [en]

    Accurate and precise assessment of human muscle tissue is important for further understanding of different muscle diseases and syndromes. We present a rapid whole body MR method for automatic quantification of total and regional muscle volume. The method is based on multi-atlas segmentation of intensity corrected water-fat separated images. The method was validated with a leave-one-out approach, using manually segmented atlases from 10 subjects as ground truth. The result gave a coefficient of variation on total muscle volume equal to 1.25±1.35 % (mean ± standard deviation). The method enables cost-efficient large-scale studies, investigating conditions such as sarcopenia and muscular dystrophies.

  • 304.
    Karlsson, Anette
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Rosander, Johannes
    Advanced MR Analytics AB, Linköping, Sweden.
    Tallberg, Joakim
    Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Grönqvist, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dahlqvist Leinhard, Olof
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Automatic and Quantitative Assessment of Total and Regional Muscle Tissue Volume using Multi-Atlas Segmentation2015In: International Society for Magnetic Resonance in Medicince Annual Meeting: Proceedings, 2015Conference paper (Other academic)
    Abstract [en]

    The purpose is to develop and demonstrate a rapid whole-body MRI method for automatic quantification of total and regional lean skeletal muscle volume. Quantitative water and fat separated image volumes of the whole body are manually segmented and used as atlases. The atlases are non-rigidly registered onto to a new image volume and the muscle groups are classified using a voting scheme. A leave-one-out approach with subjects scanned in a 1.5 T and a 3.0 T scanner is used for validation. The method quantifies the whole-body skeletal muscle volumes and the volumes of separate muscle groups independently of image resolution.

  • 305.
    Karlsson, Anette
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Rosander, Johannes
    Tallberg, Joakim
    Romu, Thobias
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Borga, Magnus
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Whole Body Muscle Classification using Multiple Prototype Voting2013Conference paper (Other academic)
  • 306.
    Karlsson, Daniel
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    A design and prototype for a decision-support system in the field of urinary tract infections: application of openGALEN techniques for indexing medical information2001In: Studies in Health Technology and Informatics, ISSN 0926-9630, E-ISSN 1879-8365, Vol. 84, no 1, p. 479-483Article in journal (Refereed)
    Abstract [en]

    Differences in expert and end-user contexts may be detrimental to the use of decision-support systems. A way to attend to this problem is to triangulate decision-support methods and information sources such as in the case of the expertext system model. To organize the information contained in the system, a common domain model is suggested as a instrument for annotating information. In this paper, a design and a prototype for a decision-support system in the field of urinary tract infections using techniques and methods developed in the GALEN projects is presented.

  • 307.
    Karlsson, Daniel
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, The Institute of Technology.
    Aspects of the use of medical decision-support systems: the role of context in decision support2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is a great need today for distribution of medical information. The amount of information is growing quickly, and information that could potentially influence clinical practice fails to reach health care professionals. The supply of information to health care has from the start been the main goal of medical informatics. However, with very few exceptions, the systems developed to support the formalization and distribution of medical knowledge, i.e. decision-support or expert systems, have not attained clinical use. Thus, since there is an unsatisfied need for information and the methods developed so far have been successful to only a limited extent, it is important to gain insight into both how decision-support systems are used and which of their properties may influence the usability.

    This thesis describes aspects of the use of medical decision-support systems by looking at two prototype implementations of such systems. The prototypes concerned bacterial endocarditis and urinary tract infections respectively. The first prototype system was evaluated and a theory of the use of the system was developed, thereby leading to further theorization and the development of a new system design. The goal of the system designs was to facilitate the interpretation and assessment of generated advice. This kind of support was realized by applying an expertext system model, a model that supports triangulation of decision-support methods and information sources. To organize the information in an expertext environment, a common terminological domain model was used in the second system design. In the theorization, a special focus was on contextual aspects of system use. Differences between knowledge provider and end-user contexts concerning the use of decision-support systems were analyzed. The importance of support for multi-perspective interpretation of system output such as is present in our system designs was confirmed.

    List of papers
    1. Extended telemedical consultation using Arden Syntax based decision support, hypertext and WWW technique
    Open this publication in new window or tab >>Extended telemedical consultation using Arden Syntax based decision support, hypertext and WWW technique
    Show others...
    1997 (English)In: Methods of Information in Medicine, ISSN 0026-1270, Vol. 36, no 2, p. 108-114Article in journal (Refereed) Published
    Abstract [en]

    There is an obvious need for geographic distribution of expert knowledge among several health care units without increasing the cost of on-site expertise in locations where health care is provided. This paper describes the design of a knowledge-based decision-support system for extended consultation in clinical medicine. The system is based on Arden Syntax for Medical Logic Modules and hypertext using World Wide Web technology. It provides advice and explanations regarding the given advice. The explanations are presented in a hypertext format allowing the user to browse related information and to verify the relevance of the given advice. The system is intended to be used in a closed local network. With special precautions regarding issues of safety and patient security, the system can be used over wider areas such as in rural medicine. A prototype has been developed in the field of clinical microbiology and infectious diseases regarding infective endocarditis.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13333 (URN)9242006 (PubMedID)
    Available from: 2008-06-18 Created: 2008-06-18 Last updated: 2017-12-13
    2. A study of the usage of a decision-support system for infective endocarditis
    Open this publication in new window or tab >>A study of the usage of a decision-support system for infective endocarditis
    2000 (English)In: Medical informatics and the Internet in medicine (Print), ISSN 1463-9238, E-ISSN 1464-5238, Vol. 25, no 1, p. 1-18Article in journal (Refereed) Published
    Abstract [en]

    The objective of this study was to examine a design for a World Wide Web-based decision-support system in use by clinically active physicians. A prototype implementation of the design concerned management of infective endocarditis patient cases. The design was based on an integration of hypertext and rule-based knowledge. In the study sessions, physicians in the field of internal medicine worked on managing authentic patient cases in a laboratory setting. Data was collected from interviews with the physicians using video recordings and stimulated recall technique. The qualitative data was analysed according to the constant comparative method in order to develop a model of the physicians' usage of the system. The resulting model describes perceived contributions and criteria for usefulness of the system. The ways the physicians used the system showed that it was able to provide patient-specific support for confirming clinical decisions, for higher-level patient management, and for preparing for and initiating expert consultations. Users also stated that new medical knowledge could be gained as a side effect of using the system.

    Keywords
    Decision-support System, Endocarditis, Qualitative Methodology, Evaluation
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-13334 (URN)10.1080/146392300298229 (DOI)
    Available from: 2008-06-18 Created: 2008-06-18 Last updated: 2017-12-13
    3. A study of the concept of urinary tract infections in different domains of medicine using the MEDLINE® database
    Open this publication in new window or tab >>A study of the concept of urinary tract infections in different domains of medicine using the MEDLINE® database
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    In the construction of decision-support systems, differences between expert and end-user domains may pose a problem. As a way of studying differences between medical domains regarding management of urinary tract infections, we investigated the MEDLINE® for differences in indexing patterns. Further, our intention was to assess the MEDLINE® database as a source for studying medical domains. We examined the use of main headings, subheadings and the level of main headings in six medical domains that manage urinary tract infections. Many intuitive but also some counterintuitive results were found. We conclude that it is difficult to use the MEDLINE® database for studying medical domains mainJy due to unclear semantics both in the headings and the indexing process, which results in variability in indexing. This variability probably hides significant results. We also conclude that the differences found indicate that in addition to differences between domains, there are also large variations within domains.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-88955 (URN)
    Available from: 2013-02-19 Created: 2013-02-19 Last updated: 2013-02-19
    4. Medical decision-support systems and the concept of context
    Open this publication in new window or tab >>Medical decision-support systems and the concept of context
    2004 (English)In: Medical informatics and the Internet in medicine (Print), ISSN 1463-9238, E-ISSN 1464-5238, Vol. 29, no 2, p. 109-118Article in journal (Refereed) Published
    Abstract [en]

    Medical decision-support systems are of necessity multi-contextual in nature. There are always at least two contexts involved in the use of such systems: the expert knowledge-provider context and the end-user context. To show this, we present examples of context-dependent aspects significant to the use of decision-support systems. The existence of discrepancies between the contexts threatens to disrupt the rationale for using decision-support systems: for the system to transfer knowledge from the expert to the end-user. Both theoretical and empirical studies show that such discrepancies exist and that they may be detrimental to the use of decision-support systems. Systems must thus give support in interpreting the output produced by the system in the context of the end-user. © 2004 Taylor and Francis Ltd.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-28810 (URN)10.1080/14639230410001684404 (DOI)13998 (Local ID)13998 (Archive number)13998 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13
    5. A design and prototype for a decision-support system in the field of urinary tract infections: application of openGALEN techniques for indexing medical information
    Open this publication in new window or tab >>A design and prototype for a decision-support system in the field of urinary tract infections: application of openGALEN techniques for indexing medical information
    2001 (English)In: Studies in Health Technology and Informatics, ISSN 0926-9630, E-ISSN 1879-8365, Vol. 84, no 1, p. 479-483Article in journal (Refereed) Published
    Abstract [en]

    Differences in expert and end-user contexts may be detrimental to the use of decision-support systems. A way to attend to this problem is to triangulate decision-support methods and information sources such as in the case of the expertext system model. To organize the information contained in the system, a common domain model is suggested as a instrument for annotating information. In this paper, a design and a prototype for a decision-support system in the field of urinary tract infections using techniques and methods developed in the GALEN projects is presented.

    Place, publisher, year, edition, pages
    Amsterdam: IOS Press, 2001
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-29003 (URN)10.3233/978-1-60750-928-8-479 (DOI)14236 (Local ID)14236 (Archive number)14236 (OAI)
    Conference
    MEDINFO 2001, 10th World Congress on Medical Informatics, London, United Kingdom
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2017-12-13
  • 308.
    Karlsson, Daniel
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Design and evaluation of a clinical decision and information support system1997Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is an obvious need today for distribution of medical information and expert knowledge among health-care providers. The ever-expanding volume of the biomedical knowledge base and the reduced funding in health-care organisations make the task of keeping up-to-date with developments in clinical medicine difficult. Nevertheless, this new knowledge must continually be shared among health-care providers. There is consequently a need for decision and information support in clinical practice.

    This thesis describes attempts at using information techniques to meet this information need. In the work addressed in this thesis, a decision and information-support system with the aim of providing geographically distributed expert knowledge has been designed, implemented and assessed with respect to user satisfaction. The system design is based on the integration of rule-based and hypertext knowledge representations to provide efficient access to clinically relevant information and extended explanations to given advice.

  • 309.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Aspevall, Olle
    Karolinska Inst, Stockholm .
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    A desision support system for urinary tract infections1999In: AMIA99,1999, Philadelphia: Hanley & Belfuse Inc , 1999, p. 1094-Conference paper (Refereed)
  • 310.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Aspevall, Olle
    KI, Huddinge .
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    Concepts, contexts and expert systemms1999In: Medical Informatics Europe99,1999, Amsterdam: IOS Press , 1999, p. 713-Conference paper (Refereed)
  • 311.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Aspevall, Olle
    Department of Immunology, Microbiology, pathology and Infectious Diseases, Karolinska Institutet, Stockholm, Sweden.
    Åhlfeldt, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Forsum, Urban
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    A study of the concept of urinary tract infections in different domains of medicine using the MEDLINE® databaseManuscript (preprint) (Other academic)
    Abstract [en]

    In the construction of decision-support systems, differences between expert and end-user domains may pose a problem. As a way of studying differences between medical domains regarding management of urinary tract infections, we investigated the MEDLINE® for differences in indexing patterns. Further, our intention was to assess the MEDLINE® database as a source for studying medical domains. We examined the use of main headings, subheadings and the level of main headings in six medical domains that manage urinary tract infections. Many intuitive but also some counterintuitive results were found. We conclude that it is difficult to use the MEDLINE® database for studying medical domains mainJy due to unclear semantics both in the headings and the indexing process, which results in variability in indexing. This variability probably hides significant results. We also conclude that the differences found indicate that in addition to differences between domains, there are also large variations within domains.

  • 312.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Aspvall, Olle
    KI.
    Åhlfeldt, Hans
    Linköping University, Department of Biomedical Engineering.
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    Using the MEDLINE® database to study the concept of urinary tract infections in different domains of medicine2004In: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 109, no 2, p. 141-157Article in journal (Refereed)
    Abstract [en]

    As a way of exploring differences between medical domains regarding management of urinary tract infections, we investigated the MEDLINE® database for differences in indexing patterns. Further, our intention was to assess the MEDLINE® database as a source for studying medical domains. We examined the use of main headings, subheadings and the level of main headings in six medical domains that manage urinary tract infections. Many intuitive but also some counterintuitive results were found indicating that the MEDLINE® database is difficult to use for studying medical domains mainly due to unclear semantics both in the headings and the indexing process, which results in variability in indexing. This variability probably hides sig-nificant results. We also conclude that the differences found indicate that in addition to differences between domains, there are also large variations within domains.

  • 313.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Budrionis, AndriusNorwegian Centre for Integrated Care and Telemedicine, University Hospital of North Norway.Bygholm, AnnAalborg University/e-Learning Lab, Danmark.Fossum, MariannUniversity of Agder, Norge.Granja, ConceiçãoNorwegian Centre for Integrated Care and Telemedicine, University Hospital of North Norway.Hartvigsen, GunnarUniveristy of Tromsö, Norge.Hejlesen, OleAalborg university, Danmark.Hägglund, MariaKarolinska institutet.Johansen, Monika AliseInstitutt for klinisk medisin, Norge.Martinez, SantiagoUniversity of Agder, Norge.Moe, Carl E.University of Agder, Norge.Marco-Ruiz, LuisNorwegian Centre for Integrated Care and Telemedicine, Univeristy of North Norway.Vimarlund, VivianLinköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Science & Engineering.Yigzaw, Kassaye Y.University of Tromsö, Norge.
    Proceedings from The 14th Scandinavian Conference on Health Informatics 2016: Gothenburg, Sweden, April 6-7 20162016Conference proceedings (editor) (Refereed)
    Abstract [en]

    The Scandinavian Conference on Health Informtics 2016 is organized together with the national health informatics organisations in Denmark, Norway, and Sweden and this year also the Vitalis conference. The goal of the conference is to stimulate scientific discussion of health informatics issues in the Scandinavian countries. The target audience of the conference are people doing, or having an interest in, health informatics research in a wide sense, including any development, implementation, evaluation, or teaching of information technology and/or managment in the health sector.

    The conference takes place at Svenska Mässan in the city of Gothenburg, close to the city center and hotels. Conference Themes

    • eHealth services, business models and implementation
    • ICT-based systems in health care
    • Electronic health record, solutions, implementations, experiences
    • Telemedicine, Tele-homecare
    • Decision support, standardized care plans, expert systems
    • Terminologies and ontologies
    • Healthcare quality
    • Modeling and standardisation
    • Healthcare information infrastructure
    • Sharing of and access to health information
    • Cooperation and interaction crossing borders (e.g. organisational)
    • Care process and workflow models
    • Welfare technology, ambient assisted living and smart homes
    • Use and reuse of health information
    • Personal Health Record (PHR)
    • Health portals
    • Usability, accessibility and user interface design
    • IT security in healthcare
    • Evaluation studies
  • 314.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Carlsson, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    Wigertz, Ove
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    A design for a World Wide Web decision-support system using a controlled medical terminology1996In: AMIA1996,1996, Washington: Hanley & Belfus , 1996, p. 189-Conference paper (Refereed)
  • 315.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Ekdahl, Christer
    Linköping University, Department of Molecular and Clinical Medicine.
    Shahsavar, Nosrat
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Gill, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    Wigertz, Ove
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    A WWW-based decision-support system using medical logic modules and hypertext1996In: Medical Informatics Europe 96,1996, Amsterdam: IOS Press , 1996, p. 93-Conference paper (Refereed)
  • 316.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Ekdahl, Christer
    Linköping University, Department of Molecular and Clinical Medicine.
    Wigertz, Ove
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    A qualitative study of clinicians ways of using a decision-support system1997In: AMIA97,1997, Philadelpia: Hanley & Belfuse Inc , 1997, p. 268-Conference paper (Refereed)
  • 317.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Ekdahl, Christer
    Linköping University, Department of Molecular and Clinical Medicine.
    Wigertz, Ove
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Forsum, Urban
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Microbiology.
    Design and evaluation of a clinical decision and information support system1998In: MEDINFO 98,1998, Australia: IOS Press , 1998, p. 574-Conference paper (Refereed)
  • 318.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Ekdahl, Christer
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences.
    Wigertz, Ove
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Shahsavar, Nosrat
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Gill, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Forsum, Urban
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Extended telemedical consultation using Arden Syntax based decision support, hypertext and WWW technique1997In: Methods of Information in Medicine, ISSN 0026-1270, Vol. 36, no 2, p. 108-114Article in journal (Refereed)
    Abstract [en]

    There is an obvious need for geographic distribution of expert knowledge among several health care units without increasing the cost of on-site expertise in locations where health care is provided. This paper describes the design of a knowledge-based decision-support system for extended consultation in clinical medicine. The system is based on Arden Syntax for Medical Logic Modules and hypertext using World Wide Web technology. It provides advice and explanations regarding the given advice. The explanations are presented in a hypertext format allowing the user to browse related information and to verify the relevance of the given advice. The system is intended to be used in a closed local network. With special precautions regarding issues of safety and patient security, the system can be used over wider areas such as in rural medicine. A prototype has been developed in the field of clinical microbiology and infectious diseases regarding infective endocarditis.

  • 319.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Forsum, Urban
    Linköping University, Department of Molecular and Clinical Medicine, Clinical Microbiology. Linköping University, Faculty of Health Sciences.
    Medical decision-support systems and the concept of context2004In: Medical informatics and the Internet in medicine (Print), ISSN 1463-9238, E-ISSN 1464-5238, Vol. 29, no 2, p. 109-118Article in journal (Refereed)
    Abstract [en]

    Medical decision-support systems are of necessity multi-contextual in nature. There are always at least two contexts involved in the use of such systems: the expert knowledge-provider context and the end-user context. To show this, we present examples of context-dependent aspects significant to the use of decision-support systems. The existence of discrepancies between the contexts threatens to disrupt the rationale for using decision-support systems: for the system to transfer knowledge from the expert to the end-user. Both theoretical and empirical studies show that such discrepancies exist and that they may be detrimental to the use of decision-support systems. Systems must thus give support in interpreting the output produced by the system in the context of the end-user. © 2004 Taylor and Francis Ltd.

  • 320.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Gøeg, Kirstine Rosenbeck
    Department of Health Science and Technology, Aalborg University.
    Örman, Håkan
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Højen, Anne Randorff
    Department of Health Science and Technology, Aalborg University.
    Semantic Krippendorff’s α for measuring inter-rater agreement in SNOMED CT coding studies2014In: e-Health – For Continuity of Care / [ed] Christian Lovis, et al., Amsterdam, 2014, p. 151-155Conference paper (Refereed)
    Abstract [en]

    Semantic interoperability requires consistency in use of terminologies such as SNOMED CT. Inter-rater agreement measurement can be used to quantify this consistency among terminology users. Increasingly, studies of SNOMED CT include inter-rater agreement measures. However, published studies do not consider distance between concepts when calculating the inter-rater agreement measures. In this paper we propose a semantic inter-rater agreement measure for use with SNOMED CT encoded data. A semantic Krippendorff's α measure is implemented using a path-length based difference function. The measure is tested using three different datasets. Results show that the proposed semantic measure is sensitive to seriousness of coding differences whereas a nominal measure is not. The proposed measure reflects the intuition that distance matters when comparing uses of SNOMED CT.

  • 321.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Lind, Leili
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering. SICS East Swedish ICT, Linköping, Sweden.
    Archetype Representation of PROMs2015In: Digital Healthcare Empowering Europeans: Proceedings of MIE2015 / [ed] R. Cornet et al., Amsterdam: IOS Press, 2015, Vol. 210, p. 980-980Conference paper (Other academic)
  • 322.
    Karlsson, Daniel
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Nyström, Mikael
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    Kron, Bengt
    Region Västra Götaland.
    An integrated Expression Repository EHR system2012Conference paper (Other academic)
    Abstract [en]

    Introduction: The aim of this work is to develop and test a system for storing and querying pre- and post-coordinated SNOMED CT expressions in an Electronic Health Record (EHR) system. SNOMED CT is here used as a reference terminology and to allow abstraction of EHR data for transfer to quality databases.

    Background: Enumerating all combinations of SNOMED CT concepts is not possible due to combinatorial explosion. E.g. pain may be qualified by severity (7 severities), pain character (152), body site (25888 sites), course (31) etc. giving a total of some 800 million possible, although not always sensible, different ways to express pain.

    For SNOMED CT to be useful, terminology services need to be integrated with the other parts of the information infrastructure, e.g. EHRs. As the boundary between terminology and information model representation may vary among use cases, care should be taken in implementing such integrations.

    Results: A system is developed to support the management of post-coordinated SNOMED CT expressions. This expression repository allows subsumption testing of pre- and post-coordinated expressions using a full view, i.e. historical views are possible. A transitive closure of the Is a-relation is updated continuously with new post-coordinated expressions stored in the repository. The repository is also integrated with an openEHR-based EHR system including archetype querying possibilities. The integrated system allows querying of terminology-bound archetype instances using pre- and post-coordinated SNOMED CT expressions.

  • 323.
    Karlsson, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Åhlfeldt, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    A comment on the Help-system: A program for medical decision making from the early 1970s1999In: Yearbook of Medical Inforamtics 1999, Stuttgart: Schattauer , 1999, p. 103-105Chapter in book (Other academic)
  • 324.
    Kircher, Albert
    et al.
    Technical University Graz Austria.
    Antonsson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Babic, Ankica
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Ahn, Henrik Casimir
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Quantitative data analysis for exploring outcomes in cardiac surgery1999In: Medical Informatics Europe99,1999, Amsterdam: IOS Press , 1999, p. 457-Conference paper (Refereed)
  • 325.
    Kircher, Albert
    et al.
    Technical University, Graz .
    Babic, Ankica
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Ahn, Henrik Casimir
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Outcome analysis for improvements in quality of care and patient wellbeing following cardiac artery By-pass surgery1999In: AMIA99,1999, Philadelphia: Hanley & Belfus Inc , 1999, p. 1100-Conference paper (Refereed)
  • 326.
    Kircher, Albert
    et al.
    Technical University Graz Austria.
    Granfeldt, Hans
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Babic, Ankica
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Antonsson, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Lönn, Urban
    Hjärtcentrum, Universitetssjukhuset Linköping.
    Ahn, Henrik Casimir
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Thoracic Surgery. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Knowledge representation forms for data mining methodologies as applied in thoracic surgery2000In: AMIA,2000, Philadelphia: Hanley & Belfus Inc , 2000, p. 428-432Conference paper (Refereed)
    Abstract [en]

    Typical ways of disseminating and using results of clinical research are scientific journals and reports. Presentation forms are condensed and comprehensible mainly to the experts following the specific topics. A vast amount of information remains unutilized due to the complex form of presenting the knowledge. Subject of this research is to explore possibilities of representation and also visualization of the results obtained using data mining methodologies. The intention is to formulate more than scientific ways to communicate facts that are of interest for the clinicians, medical students and even patients. Internet technologies as already widely established media support knowledge representation forms such as hypertext documents and structured knowledge components. The "Assist Me" decision support system for surgical treatment of cardiac patients integrates several forms of data mining and representation methodologies. We are showing a feasibility study in which scientific outcomes were forwarded to a broad group of potential users.

  • 327.
    Kjellgren, Karin
    et al.
    Hälsouniversitet Linköping.
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Dahlöf, Björn
    Sahlgrenska sjukhuset Göteborg.
    Gill, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Patients' and physicians' assessment of risks associated with hypertension and benefits from treatment1998In: Journal of Cardiovascular Risk, ISSN 1350-6277, E-ISSN 1473-5652, Vol. 5, p. 161-166Article in journal (Refereed)
  • 328.
    Kjellgren, Karin
    et al.
    Hälsouniveristetet LInköping.
    Ahlner, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Pharmacology.
    Dahlöf, Björn
    Sahlgrenska sjukhuset Göteborg.
    Gill, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Perceived symptoms amongst hypertensive patients in routine clinical practice - a population-based study1998In: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 244, p. 325-332Article in journal (Refereed)
  • 329.
    Klasson, Filip
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Väyrynen, Patrik
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Development of an API for creating and editing openEHR archetypes2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Archetypes are used to standardize a way of creating, presenting and distributing health care data. In this master thesis project the open specifications of openEHR was followed. The objective of this master thesis project has been to develop a Java based API for creating and editing openEHR archetypes. The API is a programming toolbox that can be used when developing archetype editors. Another purpose has been to implement validation functionality for archetypes. An important aspect is that the functionality of the API is well documented, this is important to ease the understanding of the system for future developers. The result was a Java based API that is a platform for future archetype editors. The API-kernel has optional immutability so developed archetypes can be locked for modification by making them immutable. The API is compatible with the openEHR specifications 1.0.1, it can load and save archetypes in ADL (Archetype Definition Language) format. There is also a validation feature that verifies that the archetype follows the right structure with respect to predefined reference models. This master thesis report also presents a basic GUI proposal.

  • 330.
    Knudsen, Greger
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, Faculty of Science & Engineering. University of Bergen, Norway.
    Babic, Ankica
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering. University of Bergen, Norway.
    Identifying Dyscalculia Symptoms Related to Magnocellular Reasoning Using Smartphones2016In: UNIFYING THE APPLICATIONS AND FOUNDATIONS OF BIOMEDICAL AND HEALTH INFORMATICS, IOS PRESS , 2016, Vol. 226, p. 229-232Conference paper (Refereed)
    Abstract [en]

    This paper presents a study that has developed a mobile software application for assisting diagnosis of learning disabilities in mathematics, called dyscalculia, and measuring correlations between dyscalculia symptoms and magnocellular reasoning. Usually, software aids for dyscalculic individuals are focused on both assisting diagnosis and teaching the material. The software developed in this study however maintains a specific focus on the former, and in the process attempts to capture alleged correlations between dyscalculia symptoms and possible underlying causes of the condition. Classification of symptoms is performed by k-Nearest Neighbor algorithm classifying five parameters evaluating users skills, returning calculated performance in each category as well as correlation strength between detected symptoms and magnocellular reasoning abilities. Expert evaluations has found the application to be appropriate and productive for its intended purpose, proving that mobile software is a suitable and valuable tool for assisting dyscalculia diagnosis and identifying root causes of developing the condition.

  • 331.
    Knutsson, H.
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Andersson, M.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Morphons: Segmentation using Elastic Canvas and Paint on Priors 2004Report (Other academic)
  • 332.
    Knutsson, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Andersson, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Implications of invariance and uncertainty for local structure analysis filter sets2005In: Signal processing. Image communication, ISSN 0923-5965, E-ISSN 1879-2677, Vol. 20, no 6, p. 569-581Article in journal (Refereed)
    Abstract [en]

    The paper discusses which properties of filter sets used in local structure estimation that are the most important. Answers are provided via the introduction of a number of fundamental invariances. Mathematical formulations corresponding to the required invariances leads up to the introduction of a new class of filter sets termed loglets. Loglets are polar separable and have excellent uncertainty properties. The directional part uses a spherical harmonics basis. Using loglets it is shown how the concepts of quadrature and phase can be defined in n-dimensions. It is also shown how a reliable measure of the certainty of the estimate can be obtained by finding the deviation from the signal model manifold. Local structure analysis algorithms are quite complex and involve a lot more than the filters used. This makes comparisons difficult to interpret from a filter point of view. To reduce the number 'free' parameters and target the filter design aspects a number of simple 2D experiments have been carried out. The evaluation supports the claim that loglets are preferable to other designs. In particular it is demonstrated that the loglet approach outperforms a Gaussian derivative approach in resolution and robustness. (c) 2005 Elsevier B.V. All rights reserved.

  • 333.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Loglets: Generalized quadrature and phase for local spatio-temporal structure estimation2003In: Image Analysis: 13th Scandinavian Conference, SCIA 2003 Halmstad, Sweden, June 29 – July 2, 2003 Proceedings / [ed] Josef Bigun and Tomas Gustavsson, Springer Berlin/Heidelberg, 2003, Vol. 2749, p. 741-748Chapter in book (Refereed)
    Abstract [en]

    The question of which properties of a local structure estimator are important is discussed. Answers are provided via the introduction of a number of fundamental invariances. Mathematical formulations corresponding to the required invariances leads up to the introduction of a new class of filter sets termed loglets. Using loglets it is shown how the concepts of quadrature and phase can be defined in n-dimensions. A number of experiments support the claim that loglets are preferable to other designs. In particular it is demonstrated that the loglet approach outperforms a Gaussian derivative approach in resolution and robustness to variations in object illumination. It is also shown how a measure of the certainty of the estimate can be obtained using the consistency of the generalized phase with respect to orientation.

  • 334.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Morphones: Paint on priors and elastic canvas for segmentation and registration2005In: Image Analysis: 14th Scandinavian Conference, SCIA 2005, Joensuu, Finland, June 19-22, 2005. Proceedings, Springer Berlin/Heidelberg, 2005, p. 292-301Conference paper (Refereed)
    Abstract [en]

    This paper presents a new robust approach for registration and segmentation. Segmentation as well as registration is attained by morphing of an N-dimensional model, the Morphon, onto the Ndimensional data. The approach is general and can, in fact, be said to encompass much of the deformable model ideas that have evolved over the years. However, in contrast to commonly used models, a distinguishing feature of the Morphon approach is that it allows an intuitive interface for specifying prior information, hence the expression paint on priors. In this way it is simple to design Morphons for specific situations.

    The priors determine the behavior of the Morphon and can be seen as local data interpreters and response generators. There are three different kinds of priors: – material parameter fields (elasticity, viscosity, anisotropy etc.), – context fields (brightness, hue, scale, phase, anisotropy, certainty etc.) and – global programs (filter banks, estimation procedures, adaptive mechanisms etc.).

    The morphing is performed using a dense displacement field. The field is updated iteratively until a stop criterion is met. Both the material parameter and context fields are addressed via the present displacement field. In each iteration the neighborhood operators are applied, using both data and the displaced parameter fields, and an incremental displacement field is computed.

    An example of the performance is given using a 2D ultrasound heart image sequence where the purpose is to segment the heart wall. This is a difficult task even for trained specialists yet the Morphon generated segmentation is highly robust. Further it is demonstrated how the Morphon approach can be used to register the individual images. This is accomplished by first finding the displacement field that aligns the morphon model with the heart wall structure in each image separately and then using the displacement field differences to align the images.

  • 335.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Morphons: Segmentation using elastic canvas and paint on priors2005In: Image Processing, 2005. ICIP 2005. IEEE International Conference on  (Volume:2 ), 2005, p. 1226-1229Conference paper (Refereed)
    Abstract [en]

    This paper presents a new robust approach for segmentation. The segmentation is attained by morphing of an TV-dimensional model, the Morphon, onto the TV-dimensional data. The approach is general and can, in fact, be said to encompass much of the deformable model ideas that have evolved over the years. However, in contrast to commonly used models, a distinguishing feature of the Morphon approach is that it allows an intuitive interface for specifying prior information, hence the expression paint on priors. In this way it is simple to design Morphons for specific situations. The priors determine the behavior of the Morphon and can be seen as local data interpreters and response generators. There are three different kinds of priors: material parameter fields (elasticity, viscosity, anisotropy etc.), context fields (brightness, hue, scale, phase, anisotropy, certainly etc.) and global programs (filter banks, estimation procedures, adaptive mechanisms etc.). The morphing is performed using a dense displacement field. Both the material parameter and context fields are addressed via the present displacement field. An example of the performance of is given using 2D ultrasound images of a heart where the purpose is to segment the heart wall.

  • 336.
    Knutsson, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Andersson, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Morphons: Segmentation using elastic canvas and paint on priors2005Report (Other academic)
  • 337.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    What's so good about quadrature filters?2003In: Image Processing, 2003. ICIP 2003. Proceedings. 2003 International Conference on  (Volume:3 ), IEEE Signal Processing Society, 2003, p. 61-64Conference paper (Refereed)
    Abstract [en]

    The paper argues for the use of quadrature filters for local structure tensor and motion estimation. The question of which properties of a local motion estimator are important is discussed. Answers are provided via the introduction of a number of fundamental invariances that are required in object motion estimation. A combination of statistical and deterministic modeling leads to mathematical formulations corresponding to the required invariances. The discussion leads up to the introduction of a new class of filter sets loglets. A number of experiments support the claim that loglets are preferable to other designs. In particular it is demonstrated that the loglet approach outperforms a Gaussian derivative approach in resolution and robustness to variations in object illumination.

  • 338.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Wigström, Lars
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Respiratory Arifact Reduction in MRI using Dynamic Deformation Modelling2002Conference paper (Other academic)
    Abstract [en]

    This paper presents a novel magnetic resonance imaging (MRI) reconstruction method that will reconstruct an object correctly despite the presence of respiratory-type motions. The basis for the method is the observation that affine deformations of an object will correspond to a different but unique affine coordinate transform of the Fourier representation (k-space) of the object. The resulting sample points will be irregularly distributed prohibiting the use of standard IFFT to reconstruct the object. The object can however be reconstructed through the use of a weighted regularized pseudo inverse. Short computing times are obtained using a novel fast sequential pseudo inverse algorithm.

     

  • 339.
    Knutsson, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Andersson, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Borga, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    Wiklund, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Computer Vision.
    Automated generation of representations in vision2000In: International Conference on Pattern Recognition ICPR,2000, Barcelona, Spain: IEEE , 2000, p. 59-66 vol.3Conference paper (Refereed)
    Abstract [en]

    This paper presents a general strategy for automated generation of efficient representations in vision. The approach is highly task oriented and what constitutes the relevant information is defined by a set of examples. The examples are pairs of situations that are dependent through the chosen feature but are otherwise independent. Particularly important concepts in the work are mutual information and canonical correlation. How visual operators and representations can be generated from examples are presented for a number of features, e.g. local orientation, disparity and motion. Interesting similarities to biological vision functions are observed. The results clearly demonstrates the potential of combining advanced filtering techniques and learning strategies based on canonical correlation analysis (CCA).

  • 340.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Andersson, Mats T.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Kronander, Torbjörn
    n/a.
    Hemmendorff, Magnus
    n/a.
    Digital Adaptive Angiocardiography1998In: Proceedings of the SSAB symposium on image analysis: Uppsala, Sweden, 1998, p. 65-68Conference paper (Refereed)
  • 341.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Wigström, Lars
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Borga, Magnus
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Sigfridsson, Andreas
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Motion artifact reduction in MRI through generalized DFT2004In: Biomedical Imaging: Nano to Macro, 2004. IEEE International Symposium on, IEEE , 2004, p. 896-899 vol.1Conference paper (Refereed)
    Abstract [en]

    This paper presents a method that dramatically reduces artifacts caused by respiratory (and similar types of) patient motion in magnetic resonance imaging (MRI). The basis for the method is the observation that affine deformations of an object will correspond to a different but unique affine coordinate transform (plus phase shift) of the Fourier representation of the object. The resulting sample points will be irregularly distributed prohibiting the use of standard IFFT to reconstruct the object. The object can however be reconstructed through the use of a weighted regularized pseudo inverse. A standard pseudo inverse is, however, not possible due to excessive computational demands. For this reason a novel fast sequential pseudo inverse algorithm is also presented. Significantly improved results are obtained on both synthetic and clinical data.

  • 342.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Andersson, Mats
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Wiklund, Johan
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Advanced Filter Design1999In: Proceedings of the 11th Scandinavian Conference on Image Analysis: Greenland, SCIA , 1999, p. 185-193Conference paper (Refereed)
    Abstract [en]

    This paper presents a general approach for obtaining optimal filters as well as filter sequences. A filter is termed optimal when it minimizes a chosen distance measure with respect to an ideal filter. The method allows specification of the metric via simultaneous weighting functions in multiple domains, e.g. the spatio-temporal space and the Fourier space. Metric classes suitable for optimization of localized filters for multidimensional signal processing are suggested and discussed.

    It is shown how convolution kernels for efficient spatio-temporal filtering can be implemented in practical situations. The method is based on applying a set of jointly optimized filter kernels in sequence. The optimization of sequential filters is performed using a novel recursive optimization technique. A number of optimization examples are given that demonstrate the role of key parameters such as: number of kernel coefficients, number of filters in sequence, spatio-temporal and Fourier space metrics.

    The sequential filtering method enables filtering using only a small fraction of the number of filter coefficients required using conventional filtering. In multidimensional filtering applications the method potentially outperforms both standard convolution and FFT based approaches by two-digit numbers.

  • 343.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Andersson, Mats
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Wiklund, Johan
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Multiple Space Filter Design1999In: Proceedings of the SSAB symposium on image analysis: Gothenburg, 1999Conference paper (Refereed)
    Abstract [en]

    This paper presents a general approach for obtaining optimal filters as well as filter sequences. A filter is termed optimal when it minimizes a chosen distance measure with respect to an ideal filter. The method allows specification of the metric via simultaneous weighting functions in multiple domains, e.g. the spatio-temporal space and the Fourier space. It is shown how convolution kernels for efficient spatio-temporal filtering can be implemented in practical situations. The method is based on applying a set of jointly optimized filter kernels in sequence. The optimization of sequential filters is performed using a novel recursive optimization technique. A number of optimization examples are given that demonstrate the role of key parameters such as: number of kernel coefficients, number of filters in sequence, spatio-temporal and Fourier space metrics. In multidimensional filtering applications the method potentially outperforms both standard convolution and FFT based approaches by two-digit numbers.

  • 344.
    Knutsson, Hans E.
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Edholm, Paul
    n/a.
    Granlund, Gösta H.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Petersson, Christer U.
    n/a.
    Ectomography. A New Radiographic Reconstruction Method: I. Theory and Error Estimates1980In: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. BME--27, no 11, p. 640-645Article in journal (Refereed)
    Abstract [en]

    Radiographic technology has advanced considerably during the last years with the advent of reconstruction techniques allowing visualization of slices through the body. In spite of the advantage of computed tomography compared to conventional radiographic methods, there are still some shortcomings with the method If a different section of the body is desired, another recording has to be made, the width of the dice reconstructed is fixed, and a full 1800 view angle is required.

  • 345.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Granlund, Gösta H.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Fourier Domain Design of Line and Edge Detectors1980In: Proceedings of the 5th International Conference on Pattern Recognition: Miami, Florida, 1980Conference paper (Refereed)
  • 346.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Granlund, Gösta H.
    Linköping University, Department of Electrical Engineering, Computer Vision . Linköping University, The Institute of Technology.
    Bårman, Håkan
    n/a.
    A Note on Estimation of 4D Orientation1990In: Proceedings of the SSAB Symposium on Image Analysis: Linköping, 1990, p. 192-195Conference paper (Refereed)
  • 347.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Haglund, Leif
    n/a.
    Granlund, Gösta
    Linköping University, Department of Electrical Engineering, Computer Vision . Linköping University, The Institute of Technology.
    Adaptive Filtering of Image Sequences and Volumes1992In: Proceedings of International Conference on Automation, Robotics and Computer Vision: Singapore, 1992Conference paper (Refereed)
  • 348.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Haglund, Leif
    n/a.
    Granlund, Gösta H.
    Linköping University, Department of Electrical Engineering, Computer Vision . Linköping University, The Institute of Technology.
    A New Approach to Image Enhancement Using Tensor Fields1990In: Proceedings of the PROART Workshop on Vision: Sophia Antipolis, France, 1990, p. 111-115Conference paper (Refereed)
  • 349.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Haglund, Leif
    n/a.
    Granlund, Gösta H.
    Linköping University, Department of Electrical Engineering, Computer Vision . Linköping University, The Institute of Technology.
    Tensor Field Controlled Image Sequence Enhancement1990In: Proceedings of the SSAB Symposium on Image Analysis: Linköping, Sweden, 1990, p. 163-167Conference paper (Refereed)
  • 350.
    Knutsson, Hans
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Herberthson, Magnus
    Linköping University, Department of Mathematics, Mathematics and Applied Mathematics. Linköping University, Faculty of Science & Engineering.
    Westin, Carl-Fredrik
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Science & Engineering.
    An Iterated Complex Matrix Approach for Simulation and Analysis of Diffusion MRI Processes2015In: MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION - MICCAI 2015, PT I, SPRINGER INT PUBLISHING AG , 2015, Vol. 9349, p. 61-68Conference paper (Refereed)
    Abstract [en]

    We present a novel approach to investigate the properties of diffusion weighted magnetic resonance imaging (dMRI). The process of restricted diffusion of spin particles in the presence of a magnetic field is simulated by an iterated complex matrix multiplication approach. The approach is based on first principles and provides a flexible, transparent and fast simulation tool. The experiments carried out reveals fundamental features of the dMRI process. A particularly interesting observation is that the induced speed of the local spatial spin angle rate of change is highly shift variant. Hence, the encoding basis functions are not the complex exponentials associated with the Fourier transform as commonly assumed. Thus, reconstructing the signal using the inverse Fourier transform leads to large compartment estimation errors, which is demonstrated in a number of 1D and 2D examples. In accordance with previous investigations the compartment size is under-estimated. More interestingly, however, we show that the estimated shape is likely to be far from the true shape using state of the art clinical MRI scanners.

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