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Biomedical subjects

A Hasman

Publications and source records attributed to A Hasman.

At least 37 records · Page 2Linked to original sources
PubMed2003

How many neurologists/epileptologists are needed to provide reliable descriptions of seizure types?

We are developing seizure descriptions as a basis for decision support. Based on an existing dataset we used the Spearman-Brown prophecy formula to estimate how many neurologist/epileptologists are needed to obtain reliable seizure descriptions (rho = 0.9). By extending the number of participants to the required level we found that the number of participants needed to obtain a reliability coefficient of 0.9 were in accordance with the number of participants determined from the Spearman-Brown prophecy formula. Systematic differences between the participants were minor and not statistically significant.

Clinical Competence↗
PubMed2002

Medical informatics: quo vadis?

In this contribution some comments are given regarding an article of Haux et al., which is published in the same issue. After discussing some general aspects of the paper, the comments focus on patient-centred care and genomics. Trends that are observed today are used to predict the situation with respect of the use of ICT in healthcare in the year 2013. It is postulated that a shared electronic patient record in which both healthcare provider and patient enter and retrieve data will be available. The role of the patient in the management of her disease will be much larger than it is now. The impact of new knowledge coming from the field of genomics will be large. It is not possible to predict the impact on functionality and the use of healthcare information systems in 2013.

Attitude of Health Personnel↗
PubMed2002

Evaluation of two cortical fraction estimation algorithms for the calculation of dynamic magnetic resonance renograms.

With the high resolution of dynamic magnetic resonance imaging (MRI) scans it is possible to measure cortical renograms directly, but due to partial volume effects this is impossible for medullary renograms. With weighted subtraction of the cortical renogram from a mixed renogram it becomes possible to extract the medullary renogram. For this subtraction the fraction of cortical tissue, present in the region of interest in which the mixed renogram is determined, has to be calculated. We have evaluated two algorithms for calculation of the cortical fraction. Both algorithms use the fact that during an interval after the start of the cortical enhancement no medullary enhancement occurs. One algorithm calculates the ratio between the slopes of both enhancement curves. The other is based on minimising the medullary signal values using a least squares error (LSE) method. Using a computer model of the renograms and measurements on real patients we analysed the accuracy of both methods and determined the best parameters for each.

Algorithms↗
PubMed2002

Medical informatics as a discipline at the beginning of the 21st century.

OBJECTIVES: To analyse the present situation of the discipline medical informatics and to propose actions for change. METHODS: Evaluation of the current situation mainly based on anecdotal evidence. RESULTS: The difference between the scientific and the engineering aspects of medical informatics get blurred. Because of the requirements of European funding medical informatics focuses more on engineering than on science. Too many manuscripts are submitted that describe engineered artefacts without a scientific purpose. Some of the subjects (like security issues) that are studied in medical informatics are not considered important by medical faculties thus impeding support. CONCLUSIONS: The methodological underpinnings of our research should be strengthened, impact studies should be more frequently performed; the quality of results reporting should be increased.

Forecasting↗
PubMed2002

An architecture for a virtual electronic health record.

The Healthcare Domain Taskforce of the Object Management Group has specified standards for secure access and retrieval of demographic and medical data. This paper discusses the strengths and weaknesses of an electronic healthcare record that implements these specifications.

Computer Systems↗
PubMed2002

Inter-participant agreement in the selection of symptoms for the description of seizures.

PURPOSE: To evaluate the inter-participant agreement in the selection of symptoms for the description of seizure types. METHODS: We evaluated the inter-participant agreement for a number of seizure types by comparing the actual agreement to the agreement that would result from random symptom selection as well as the maximal attainable agreement among participants that selected a different number of symptoms. RESULTS: For all seizure types the agreement in the symptom selection among the majority of the participants is significantly higher than expected by chance, but not reaching the maximum agreement attainable. CONCLUSION: Although the maximum agreement possible is not obtained, the symptoms selected by a majority of the participants seem to be adequate for the description of seizure types.

Humans↗
PubMed2001

Movement correction of the kidney in dynamic MRI scans using FFT phase difference movement detection.

To measure cortical and medullary MR renograms, regions of interest (ROIs) are placed on the kidney in images acquired using dynamic MRI. Since native kidneys move with breathing, and breath-holding techniques are not feasible, movement correction is necessary. In this contribution we compare three correction methods, based on image matching, phase difference movement detection (PDMD), and cross-correlation, respectively. The PDMD-based method showed the best performance and was able to determine kidney movement in our test series in 68% of the scans with no visible deviation, and in 88% of the scans if a one-pixel deviation is considered acceptable.

Algorithms↗
PubMed2001

MR renography by semiautomated image analysis: performance in renal transplant recipients.

We evaluated a method of semiautomated analysis of dynamic MR image series in renal transplants. Nine patients were studied twice, with an average time interval of 7 days. MR examination consisted of a run of 256 T1-weighted coronal scans (GE; TR/TE/flip: = 11/3.4/60 degrees; slice thickness = 6 mm; temporal resolution = 2 seconds). Gadolinium-DTPA (0.05 mmol/kg) was injected with an injector pump (5 ml/seconds). MR renographs of the cortex and medulla were obtained by segmentation of the renal transplant and placement of two regions of interest (ROIs) overlying the peripheral and central renal parenchyma. In the first 100 frames of the renographs, analysis of variance (ANOVA) demonstrated significant intraclass correlation coefficients with mean values for the cortex and medulla of 0.47 and 0.59, respectively. We conclude that the procedure is a robust technique that generates meaningful signal curves.

Contrast Media↗
PubMed2001

Using the nursing minimum data set for the Netherlands (NMDSN) to illustrate differences in patient populations and variations in nursing activities.

RATIONALE: A nursing minimum data set (NMDS) provides data that are useful to legitimate nurses' contribution to healthcare. In Belgium and the US, such NMDS are operational, other countries are developing it, among which is the Netherlands. OBJECTIVE: To evaluate whether the nursing minimum data set for the Netherlands (NMDSN) is suitable to describe the diversity of patient populations and the variability of nursing care. METHODOLOGY: Using the NMDSN data collection forms, patient data were collected from 15 different hospital wards. During one week, nurses manually completed the NMDSN list for every patient. The data analysis methodology from the Belgian MVG was used, including ridit analysis and graphs. RESULTS: The NMDSN includes items related to hospital, patient demographics, medical condition, nursing process, nursing phenomena, nursing interventions, outcomes of nursing care, and complexity of care. There were 686 individual patients in the study, while for the data analysis their 2090 patient days in the hospital were used. Frequencies of nursing phenomena, nursing activities and results of care were calculated, transformed into ridit scores, and presented graphically as 'fingerprints'. CONCLUSION: The set of NMDSN items allows illustrating the diversity of patient populations, and variation in nursing care by means of 'fingerprints'.

Activities of Daily Living↗
PubMed2001

Simulation as decision tool for capacity planning.

In this paper we demonstrate how discrete event simulation technique can be used to optimise the use of catheterization capacity. The patient flow at the catheterization room is described. A simulation model of the current situation was built in MedModel, a discrete event simulation package, and the model was validated. A short presentation of MedModel is given. To investigate alternative ways to optimise the use of the catheterization room three experiments were formulated, modelled and simulated. Two different scheduling strategies were applied to the current situation and the three experimental situations. The number of patients that can be treated and the duration of a working day were determined as measures of performance. The results of the simulation experiments are discussed. The results of these experiments give the management of the catheterization room valuable information how to optimise the use of the catheterization room.

Cardiac Catheterization↗
PubMed2001

The application of ontologies and problem-solving methods for the development of shareable guidelines.

Recently, studies have shown the benefits of using clinical guidelines in the practice of medicine. Computer-based clinical guidelines are increasingly applied in diverse areas such as policy development, utilization management, education, conduct of clinical trials, and workflow facilitation. This paper discusses some of the representations suggested in literature, discusses their weak and strong points, and demonstrates and discusses a new approach that extends earlier developed formalisms by combining primitives, ontologies and the use of problem-solving methods (PSMs). The approach is supported by a framework that facilitates the entire guideline authoring process. The paper demonstrates this framework and presents examples of guidelines, PSMs and systems that were developed by means of this approach. The overall goal of this approach is to improve the acceptance of shareable guidelines and decision support systems in daily care by facilitating the guideline acquisition and execution phases.

Decision Support Systems, Clinical↗
PubMed2001

Design and implementation of a framework to support the development of clinical guidelines.

This paper describes and discusses a framework that facilitates the development of clinical guideline application tasks. The framework, named GASTON covers all stages in the guideline development process, ranging from the definition of models that represent guidelines to the implementation of run-time systems that provide decision support, based on the guidelines that were developed during the earlier stages. The GASTON framework consists of (1) a newly developed guideline representation formalism that uses the concepts of primitives, problem-solving methods (PSMs) and ontologies to represent the guidelines of various complexity and granularity and different application domains, (2) a guideline authoring environment that enables guideline authors to define the guidelines, based on the newly developed guideline representation formalism and (3) a guideline execution environment that translates defined guidelines into a more efficient symbol level representation, which can be read in and processed by an execution time engine. The paper describes a number of design criteria that were formulated regarding the aspects of guideline representation, guideline authoring and guideline execution and explains the framework by example in terms of the four stages that were identified in the guideline development process and the tools that were developed to support each stage. It also shows examples of systems that were developed by means of the GASTON framework.

Artificial Intelligence↗
PubMed2001

Validation of a knowledge based reminder system for diagnostic test ordering in general practice.

We describe the validation of a real-time automated reminder system that assists General Practitioners (GP) in appropriate test ordering. We compared the comments of human experts with the comments of the reminder system using a retrospective random selection of 253 request forms. A panel of three expert physicians judged the requested tests independently based on their interpretations of the practice guidelines. The majority assessment of the physicians was compared with the assessment of the reminder system. In case the system's output differed from the majority assessment the written practice guidelines were consulted. On average 1.75 reminders were produced per form. In total 32 of the 442 given reminders (7%) were given incorrectly. The amount of information and the level of detail (the specificity of the terms) in which the GP describes the patients' medical status are crucial for the reminder system to react correctly.

Adult↗
PubMed2001

Development and implementation of an EPR: how to encourage the user.

This paper reports on the role users played in the design and development of an electronic patient record. Two key users participated in the project team. All future users received questionnaires and a selection of them was interviewed. Before starting the development of the EPR, the attitude of users towards electronic record keeping, their satisfaction with the paper clinical records, their knowledge of computers, and their needs and expectations of computer applications in health care were measured by means of a questionnaire. The results of the questionnaire were supplemented with in-depth interviews. Users had a neutral attitude towards electronic record keeping. They were more positive about data entry of the paper records than data retrieval. During the development phase, but prior to the implementation of the EPR, a second questionnaire measured satisfaction with the paper records. Satisfaction appeared to be related to self-rated computer experience. Inexperienced computer users tended to be more positive about the paper records. In general, respondents did not have many expectations about electronic record keeping. A second series of interviews zoomed in on the expectations users had. Except for more concise reporting no beneficial effects of electronic record keeping were expected.

Adult↗
PubMed2001

Medical informatics and problem-based learning.

Problem-based learning (PBL) is an educational method that can be considered as an alternative to the traditional, discipline-based, approach to teaching. In this paper the characteristics of both approaches are discussed and compared. Some background knowledge concerning the principles that determine the success of instructional methods is presented. Finally, it is discussed how medical informatics can be taught in a PBL environment.

Curriculum↗
PubMed2001

Evaluation of a method that supports pathology report coding.

OBJECTIVES: The paper focuses on the problem of adequately coding pathology reports using SNOMED. Both the agreement between pathologists in coding and the quality of a system that supports pathologists in coding pathology reports were evaluated. METHODS: Six sets of three pathologists each received a different set of 40 pathology reports. Five different SNOMED code lines accompanied each pathology report. Three pathologists evaluated the correctness of each of these code lines. Kappa values and values for the reliability coefficients were determined to gain insight in the variance observed when coding pathology reports. The system that is evaluated compares a newly entered report, represented as a multi-dimensional word vector, with reports in a library, represented in the same way. The reports in the library are already coded. The system presents the code lines belonging to the five library reports most similar to the newly entered one to the pathologist in this way supporting the pathologist in determining the correct codes. A high similarity between two reports is indicated by a large value of the inproduct of the vector of the newly entered report and the vector of a report in the library. RESULTS: Agreement between pathologists in coding was fair (average kappa of 0.44). The reliability coefficient varied from 0.81 to 0.89 for the six sets of pathology reports. The system gave correct suggestions in 50% of the reports. In another 30% it was helpful for the pathologists. CONCLUSIONS: On the basis of the level of the reliability coefficients it could be concluded that three pathologists are indeed sufficient for obtaining a gold standard for evaluating the system. The method used for comparing reports is not strong enough to allow fully automatic coding. It could be shown that the system induces a more uniform coding by pathologists. An evaluation of the incorrect suggestions of the system indicates that the performance of the system can still be improved.

Clinical Laboratory Information Systems↗
PubMed2001

Reliability of the assessment of appropriateness of diagnostic test request behavior.

We describe the reliability of the assessment of the appropriateness of requested diagnostic tests. We used a retrospective random selection of 253 request forms with in total 1217 requested tests. Three experts made an independent assessment of each requested test. Interrater kappa values ranged from 0.33 to 0.44. The kappa values of intrarater agreement ranged from 0.65 to 0.68. The reliability coefficient for all three reviewers was 0.66. This reliability is not sufficient to make case-by-case decisions, for example to give individual feedback on the appropriateness of requested tests. Sixteen reviewers are necessary to obtain a reference with a reliability of 0.95.

Decision Support Systems, Clinical↗