Diagnosis supporting rules of the Hepar system.

The "Hepar" system comprises a clinical database and the shell of procedures that aim at data analysis and the support of diagnosis. The database consists of hepatological patient cases. Each case is described by about 200 medical findings and histopathologically verified diagnosis. The diagnosis supporting rules of "Hepar" are based on visualizing data transformations and on the similarity based techniques. The applied linear visualizing transformations of data sets on the plane aim at separating of the groups of patients associated with different diseases. The resulting diagnostic maps by the visual inspection allow to find such cases in the database that are similar to the previously diagnosed patients. This paper examines combining of data transformations with the nearest neighbors techniques in the support of diagnosis. We report the results on the experimental comparisons of different decision rules including the feature selection procedure.

Support of diagnosis of liver disorders based on a causal Bayesian network model.

We describe our work on HEPAR II, a probabilistic causal model for diagnosis of liver disorders. The model, a Bayesian network capturing the causal interactions among various risk factors, diseases, symptoms, and test results, is based on expert knowledge combined with clinical data captured in medical records. The main applications of HEPAR II are assistance is diagnosis and training of beginning diagnosticians. We outline the principles of the applied approach, present a brief description of the model, and report its diagnostic performance.

The four year's experience with HEPAR-computer assisted diagnostic program.

The computer system HEPAR has been outlined and prepared by the research team of medical and informatics specialists at the Medical Center of Postgraduate Education and Warsaw research institutes (Inst. Biocyb. and Biotech. PAS, Inst. of Food and Aliment), and for the last four years has been applied practically at the Clinic of Gastroenterology and Methabolic Diseases of Bródnowski Hospital in Warsaw.

["Hepar"--the clinical computer system and its diagnostic and didactic use]. / "Hepar"--kliniczny system komputerowy, zastosowanie diagnostyczno-dydaktyczne.

The possibilities of application of the "Hepar" computer system in medical didactics are discussed. The usefulness of hepatological diagnosis assistance with information++ systems is described and the multistage schema of diagnostic management is presented. In the conclusions the advantages of this system in medicine teaching is stressed and its usefulness in clinical practice is outlined.

Selection of medical tests based on linear nonseparability of data sets: a study on evaluation of liver diseases tests.

A new method of solving the problem of medical tests selection is proposed. This method is based on the notion of linear nonseparability of data. A measure of linear nonseparability is computed by minimization of the perceptron criterion function. A multistage strategy of search of the minimum sufficient tests subset is described. This strategy is reliable in the sense that it allows us to find the least (globally) sufficient number of tests. The considerations are illustrated on a liver diseases data example.