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D P Pretschner

Publications and source records attributed to D P Pretschner.

At least 19 recordsLinked to original sources
PubMed2006

Pre-operative dynamic interactive exploration of complex articular fractures using a novel 3D navigation tool.

OBJECTIVES: Trauma surgeons possess specific anticipative pathoanatomical and procedural domain knowledge that can be used for information extraction from original CT image data. This knowledge so far remains unused in clinical workflow and surgeons do not take an active part in the process of image generation and processing. The objectives of our work are to propose and employ a strategy to directly involve surgeons in a dynamic image exploration process and to exemplarily assess the clinical use of this approach for pre-operative diagnosis of complex articular fractures. METHODS: We used an interactive 3D navigation tool with a novel human-computer interface for the exploration of articular fractures of two selected anatomical structures. The system offers dynamic interaction with a virtual 3D reconstruction model and the possibility to create on-the-fly oblique multiplanar reformations by tracking hand movements. Three expert surgeons performed exemplary explorations and rated the use of the method for preoperative diagnosis in informal interviews. RESULTS: The approach and the system were well received by the three surgeons. The dynamic interaction was rated to be helpful in understanding fracture morphology. Two examples--a radius and a calcaneal fracture--are presented. CONCLUSIONS: Surgeons with their specific domain knowledge should be involved in the process of image processing. The benefit of using oblique multiplanar reformations for pre-operative planning in articular fractures appears to be substantial and they should therefore be included in radiological and surgical textbooks. Further evaluation is necessary to assess the use of interactive exploration systems in routine diagnosis.

Feasibility Studies↗
PubMed2005

Analysis and Specification of Telemedical Systems Using Modelling and Simulation: the MOSAIK-M Approach.

BACKGROUND AND MOTIVATION: INCA (Intelligent Control Assistant for Diabetes) is a project funded by the EU with the objective to improve diabetes therapy by creating a personal control loop interacting with telemedical remote control. Development of telemedical systems generally is a complex task especially in international projects where engineering and user groups with different social and cultural background have to be included into the system development process. OBJECTIVES: To explore if and how sophisticated information system modelling and simulation techniques can improve the development of telemedical systems. METHODS: For system analysis and design the MOSAIK-M approach was chosen. MOSAIK-M means "Modelling, simulation, and animation of information and communication systems in medicine". It includes a generic process scheme, a meta model and a tool environment. The generic process scheme guides modelling projects to produce models of high quality in terms of correctness, completeness and validity. The meta model defines the modelling language.In INCA MOSAIK-M is used for analysis of the problem domain, specification of the telemedical system and cost/benefit-analysis. RESULTS: The MOSAIK-M approach was used to create two models: an "As Is"-model of the problem domain and a "To Be"-model of the INCA system. The "As Is"-model of conventional insulin pump based diabetes care comprises submodels of diabetes management, ambulatory and clinical care. The "To Be"-model describes a patient's diabetes management using a smart phone that controls an insulin pump based on continuously measured interstitial glucose. It also describes telemedical care of a patient by diabetologists and a call centre. Both models can be simulated enhanced by visualisation capabilities to explore specific cases or scenarios. This feature proved valuable for the evaluation of both models through domain experts. The "To Be" model is used to guide the implementation of the system. Both models are being augmented by cost structures to support cost/benefit-analysis. CONCLUSIONS: Even a complex telemedical system like the INCA system can be successfully specified using sophisticated modelling and simulation based approaches like MOSAIK-M. The resulting specification is a result of its own and ensures a lasting effect of the definitions and specifications produced during the project. International cooperation and evaluation of the system design prior to its implementation profit from simulation and visualisation capabilities of MOSAIK-M.

Computer Simulation↗
PubMed2004

VISION2003: virtual learning units for medical training and education.

The project VISION2003 consists of several partners with different professions ranging from medicine to medical informatics, from computer science to didactics. Its aim is the development, testing, introduction and a long-time maintenance of an open, web-based, intelligent and adaptive teaching and learning system for medical education. The system is expected to enhance the acceptance and efficiency of conventional ways of learning by supplementing and supporting them and creating new methods for imparting knowledge ["VISION2003, Lehr-und Lernsysteme in der Medizin: Intelligente und Multimediale, Internetbasierte adaptive und intelligente Autorensysteme für kooperatives Training in der Medizin", (last valid on 17 January 2003) and Ein offenes sprachkonzept für verteilte wissensverarbeitung in der medizin, Tagungsabstract XVI International Congress of the European Federation for Medical Informatics MIE, September 2000]. This is done exemplarily in the specific fields of oncology, accident-surgery and cardiology in consideration of actual standards and didactical measures. The range of possible applications is wide, from electronically accessible scripts through example cases to complex simulations. The main focus of the project is the creation of an open and flexible internet platform for delivering multimedia-based learning units and the development of adaptive and intelligent authoring systems.

Computer-Assisted Instruction↗
PubMed1999

Telemedical support of prehospital emergency care in mass casualty incidents.

In the German emergency medical service system (EMSS) medical treatment can be improved in most of mass casualty incidents (MCI). Currently, the incident commander who is responsible for classification of the victims (depending on their urgency and condition, the so called triage) and ordered transportation uses paper-based documentation. Triage tags are used to identify and classify patients and gather treatment information. This can cause problems in medical treatment and in transportation of injured victims. Object-oriented modelling, simulation, and visualisation of processes can show deficits in treatment and data processing and thereby help to optimise medical workflow and logistics. If documentation by paramedics and emergency physicians is done electronically, all patient records could be send to a telemedical centre for central data administration. A telemedical supported triage tag helps identifying victims and managing detailed identification protocols. The paper-based documentation in emergency would become obsolete, if hospitals can query all protocols, diagnoses, and findings from the telemedical centre. Safety and security aspects can be guaranteed. The complete medical treatment workflow can be supported by telemedicine. Therefore, in case of MCI, telemedicine can optimise medical treatment and exonerate the paramedics from unnecessary documentation.

Allied Health Personnel↗
PubMed1997

[Rationalizing the organization and structure of a trauma surgery clinic based on rationing of personal and financial resources--analysis, simulation and conversion using modern data processing techniques].

With a system of modeling, simulation, animation of information, communication in medicine (mosaic-m) the structures of organisation and information in a level 1 trauma center were analysed and animated as a virtual environment on screen in a first step. One result: in existing paper orientated documentation 50% of documentation was redundant. In a second step the requirements of the future information system were described systematically, user- and organisation-oriented. All components (hard- and software) were simulated an screen that the user could work virtually in the future working place. With mosaic-m the user is fully integrated in analysing and developing a new information system in the clinic.

Computer Simulation↗
PubMed1996

Computer-based diagnosis support for the interpretation of Hess charts.

Computer-based storage of patient data is the basis for their comprehensive use in science and patient care. Developing a data base for storage and interpretation of strabologic data must be prepared by an analysis of data items, terminologies, and diagnostic methods. We analyzed patient data collections and constructed a minimal strabologic data structure focused on methods for the examination of eye-muscle function. Geometric methods for the analysis of Hess charts help to prepare diagnostic parameters for assignment of Hess-result figures (classified according to their shapes) to certain diagnoses of muscle paresis. In this way the system can help in preparing and verifying diagnoses and structuring data according to various scientific or patient-management needs. Moreover, the system can support diagnostic training as it can present Hess charts, related diagnoses, and geometric parameters in a concise manner and hence enable learners to understand the diagnostic procedure.

Diagnosis, Computer-Assisted↗
PubMed1995

The compositional approach for representing medical concept systems.

The representation of patient-specific information in the computer-based medical record requires an expressive formalism, which supports computational services particularly with respect to subsumption. These demands are not sufficiently met by conventional medical terminology and classification systems. This paper investigates the weaknesses of conventional systems, which are primarily coding systems and contain a certain amount of implicit knowledge. The alternatives are logic-based formalisms, particularly languages of the KL-ONE-family and conceptual graphs, which are based on the formal representation of meanings. Principles of these approaches are reported and compared to the concept representation language developed in the GALEN project. Finally, an overview on the BERNWARD model is given, which aims at the formal description, classification, and composition of medical concepts. In BERNWARD subsumption and part-whole relation are treated in a symmetrical manner. There are explicit and formal criteria for supporting the inference of generic and partitive relations.

Disease↗
PubMed1995

Specification of a computer-based information system for ophthalmology using modeling and simulation techniques.

A model of an information system for ophthalmologic practices has been constructed using an object-oriented development environment. This model allows us to dynamically visualize the proceedings in a medical environment by graphical means. The model includes an object-oriented basis data model for ophthalmologic applications and tools for the medical staff e.g., a patient record browser. Special (sub)systems can be integrated into the basis model. Some aspects of the development process will be discussed.

Computer Graphics↗
PubMed1992

Recommendations of the German Association for Medical Informatics, Biometry and Epidemiology for education and training in medical informatics.

In the fields of health care and medicine there is an immense demand for a systematic application of methods of information processing and for the use of computers. Obviously, to that end well-trained scientists and qualified personnel must be available. With the present recommendations on education and training in medical informatics the German Association for Medical Informatics, Biometry and Epidemiology (GMDS) proposes structure and contents of medical informatics curricula and courses. The recommendations describe a 2-dimensional educational framework with different education levels in one dimension and various types of educational needs and orientation in the other one. The recommendations comprise at the university level education as well specialized curricula covering the total spectrum of medical informatics as well as informatics curricula with medical informatics as integrated applied subject or subsidiary subject, respectively. Besides these informatics-oriented approaches medical-oriented programs of education in medical informatics are recommended, e.g., post-graduate education in medical informatics for physicians based on foundations in medical informatics as part of their initial training in medicine. At the level of polytechnical schools curricula of medical documentation and informatics and at the level of professional schools training in medical documentation are recommended. This report is a translation of its German original. Although considered by the GMDS as recommendations for the Federal Republic of Germany, the text may also contribute to the development of an international, especially European framework of training in medical informatics.

Germany↗
PubMed1992

Possibilities of software phantoms for quality control of KBS in nuclear medicine.

The assessment of the results of a "knowledge-based system" (KBS) for quality control is a basic requirement for clinical application: Large numbers of test studies are necessary in order to cover as widely as possible the spectrum of cases to be analyzed by the KBS. The use of original patient data as test data is one possibility, but real data are provided unevenly. This is due to the set of characteristics which are relevant to the analysis. Data are available in a limited quantity only. This implies a remaining set of unvalidated cases which are not represented in the data pool. The software phantom is an approach towards systematically guided validation. It permits the generation of test data adjusted to the demands of the validation.

Artificial Intelligence↗
PubMed1991

An interactive report generator for bone scan studies.

An interactive report generator for bone scintigraphy will be demonstrated. It comprises a controlled reporting vocabulary, an adaptive user interface, and a text generator. The controlled vocabulary represents the relevant concepts for bone scan reports: anatomical sites, scintigraphical phenomena, and diagnoses, and various attributes for these concept domains. Within the vocabulary selectional constraints are defined that restricts to meaningful combination of concepts. The interface provides intelligent views on the vocabulary, and presents only those terms that are relevant in a certain context. Through the interface the user may choose appropriate terms and combine them to complex findings. A German text generator for a restricted finding language transforms the entered data into morpho-syntactic surface structures and produces acceptable reports.

Bone and Bones↗
PubMed1988

The engymetric determination of acute functional impairment in kidney graft function caused by cyclosporine A.

Engymetry offers a new means of continuously measuring nuclear radiation fields without any need of restricting the patient's mobility. In this study, kidney function was measured simultaneously and continuously for 6.6 h with engymetry, after application of a 12 h therapy dose of Cyclosporine A (CsA) of 4.0 +/- 1.8 mg per kg bodyweight (bw). 15 kidney transplanted patients participated in this study. 370 MBq 99Tcm-DTPA and 10 MBq 131I-OIH were injected during routine transplant scintigraphy. Renal function was monitored from the external disappearance curves of the tracers recorded by portable double radionuclide detectors. Renal impairment could be seen in the rising phase of CsA or coincided with the CsA maximum in 13 of the 15 patients. Under the impairment the half-life of 99Tcm-DTPA increased from 4.1 +/- 1.2 to 15.9 +/- 12.3 h (p less than 0.005) for 61 +/- 45 min and the half-life of 131I-OIH increased from 3.2 +/- 0.7 to 12.7 +/- 8.4 h (p less than 0.001) for 71 +/- 37 min. With noninvasive engymetry it is possible to detect renal functional impairment during long observation periods. Acute restriction in glomerular filtration and renal blood flow was discovered in human kidney graft recipients after the application of a low therapeutic CsA dose.

Acute Kidney Injury↗
PubMed1986

The current situation, aspects, and projects concerning nuclear medicine software in Europe.

Since the 1984 Congress of the Society of Nuclear Medicine-Europe in Helsinki, the "Task Group for European Nuclear Medicine Software Cooperation", which became the "Joint ENMS/SNME Nuclear Medicine Software Task Group" in London in 1985, has focused attention on establishing a new COST project (European Cooperation in the Field of Scientific and Technical Research) (COST 1981) in the field of nuclear medicine Software. On 20 March 1986, the mandate was finally approved officially by the COST Committee of Senior Officials in Brussels (see Editorial in this issue). The problems, content, and objectives of specific items and ideas regarding NM software that have been publicized at the European level are dealt with here. The reader actively interested in NM software is encouraged to participate in the COST framework and forum, in order to avoid duplication of effort and to utilize resources more efficiently by coordinating activities in nuclear medicine in Europe.

Artificial Intelligence↗
PubMed1985

Difference quantitation of planar and tomographic heart scintigrams with identification of segments using reconstructive three-dimensional reference modelling.

A patient-specific three-dimensional rotational ellipsoidal shell was reconstructed from planar myocardial scintigrams. This model was homogeneously filled with radioactivity ('ideal') and then projected onto the same planes as the actual scintigrams, including the absorption of heart and background. After normalization and inhomogeneous background correction, the actual and 'ideal' images were compared in order to quantify the myocardial, ischemic and infarcted volumes (difference quantitation). 201Tl defects appeared as hot spots. The a priori three-dimensional model was cut into 14 segments by six planes. Tomographic sectional views in any desired plane made possible the identification of the 14 spatial myocardial segments on slice images for difference quantitation. The orientation of the long axis of the left heart responsible for different inseparable overprojections of segments was accounted for. The mathematics of segmentation and reconstructive three-dimensional modelling is described. Computed examples are given. A total of 624 201Tl scintigrams from 78 patients were analysed according to this method. The results obtained for the myocardial, ischemic and infarcted volumes, the orientation of the left heart's axis in the thorax and the identification of spatial myocardial segments on projected and tomographic images, as well as the global myocardial and background kinetics of 201Tl are discussed. The procedure of reference modelling and difference quantitation might also be useful in other imaging modalities, such as emission-computed tomography, single-photon emission computed tomography, computed tomography or nuclear magnetic resonance.

Heart↗
PubMed1985

[Operative indications and surgical procedure in iodine-induced hyperthyroidism].

Clinical course, indications for surgical treatment, and results of treatment in 8 female patients with iodine induced thyrotoxicosis (IIT) are reported. The diagnosis of IIT could be established in all patients by a) clinical hyperthyroidism, b) increased T3 and T4 serum concentrations, and c) previous iodine contamination. Sources of iodine were radiographic contrast agents for urography (n = 4), oral cholecystography (n = 3), intravenous cholangiography (n = 1), phlebography (n = 1), and cranial computer tomography (n = 1). The onset of hyperthyroidism occurred 1-8 weeks after iodine exposure. Indications for surgical treatment of IIT were: 1. autonomous nodular goiter (n = 6), and 2. iodine exacerbation of preexisting thyrotoxicosis in patients with Graves' disease (n = 2). Corresponding to the different pathogenesis of autonomous and immunogenetic goiter the following surgical treatment is recommended: Enucleation of solitary autonomous adenomas or unilateral lobectomy in case of large adenomas, subtotal bilateral lobectomy in toxic multinodular goiter or, preferentially, unilateral lobectomy combined with subtotal resection of the contralateral thyroid lobe; "Near-total" thyroidectomy in Graves' immunopathy.

Adult↗
PubMed1983

Pharmacokinetic parameters for thallium (I)-ions in man.

The pharmacokinetics of Tl+ were studied in 9 patients who underwent myocardial scintigraphy with 201Tl+. The time course of the 201Tl+ concentration fitted to an open two-compartment model. The following values were calculated: k12 = 0.164 +/- 0.025 min-1, k21 = 0.011 +/- 0.004 min-1, k10 = 0.005 +/- 0.004 min-1, t1/2(lambda 1) = 3.92 +/- 0.54 min, t 1/2(lambda 2) = 3108 +/- 896 min, CL = 0.08 +/- 0.03 l/min, V1 = 0.26 +/- 0.13 l/kg, Vz = 4.36 +/- 0.65 l/kg, Vss = 4.23 +/- 0.67 l/kg. Using previously published dialysance values the influence of hemodialysis on Tl+ elimination was calculated. Hemodialysis in Tl+ intoxications should be moderately effective.

Half-Life↗