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Biomedical subjects

H A Heathfield

Publications and source records attributed to H A Heathfield.

4 recordsLinked to original sources

Decision support system for the differential diagnosis of breast disease.

The histopathological diagnosis of breast disease is representative of many problems of differential diagnosis encountered in the medical domain. It requires highly trained and experienced experts and is characterized by a large number of features whose presence or absence involves much uncertainty. Computer-based decision support systems intended to function in a consultative capacity during differential diagnosis have had limited success for two fundamental reasons. Firstly, they take an autonomous role and assume that the user has no contribution to make to the problem-solving process. Secondly, the established techniques for representing and reasoning with medical knowledge are of limited suitability in this domain. Such systems are unable to reach a correct diagnosis quickly and often subject the user to a cumbersome dialogue. These are not tolerated by pathologists working under severe time constraints. We first look at the problem-solving methods employed by pathologists in this domain and examine the functionality of traditional expert system methodologies. We then present a cooperative design which allows the pathologists to express his or her ideas within a decision support system whilst gaining assistance in required areas. A novel inference technique based upon the set partitioning technique in hypergraphs is also described. This mathematical method has the ability to cope with the incomplete or inadequate knowledge which is a characteristic of breast disease, whilst directing data gathering in a meaningful manner. In particular this approach can significantly reduce the amount of irrelevant data which the pathologist must enter before a conclusion is reached. Thus it can potentially improve the efficiency and user acceptability of medical expert systems.

Algorithms

Computer assisted diagnosis of fine needle aspirate of the breast.

The development of the National Breast Screening Programme has created a demand for the widespread availability of fine needle aspiration cytology services. To meet this demand there must be a rapid increase in the number of pathologists and laboratories able to offer this service. In turn there is a need for improved training methods. The technique of fine needle aspiration cytology is not inherently complicated. The number of possible conclusions is essentially limited to four: unsatisfactory, benign, suspicious and malignant. A computer based expert system, designed to assist pathologists in the diagnosis of fine needle aspirates of the breast, has been developed. The system prompts pathologists to categorize a number of variables in the aspirate including nuclear and cytoplasmic features, and the degree of cellular cohesion, and uses these data to reason about possible conclusions. The final diagnosis is displayed with a detailed explanation listing the factors supporting it. Initial trials with this system have been encouraging and it is envisaged that this system will be of value both in training and as an aid to routine diagnosis.

Biopsy, Needle

Computer-assisted breast cancer grading.

Morphological tumour differentiation has been shown in numerous studies to give a good prognosis in breast cancer, but as histological grading is based upon a subjective assessment of microscopical appearances, difficulties in consistency and reproducibility are inevitable. A review of the many conventional methods served to highlight a common limitation in their approach; lack of structure. We introduce a new approach which seeks to overcome the problem, by formalizing the methods and identifying aspects which are well suited to computer aided analysis, these being incorporated into a microcomputer system facilitating the collection and appraisal of morphometric data. Within the Information Technology Institute (ITRI) at Brighton Polytechnic a research team is carrying out multidisciplinary work into the elucidation of biological systems. This programme, entitled 'Intelligent Medical Systems', used methods of mathematical signal processing and artificial intelligence, applied to a number of areas, one of which is described in this paper. The aim has been to utilize the inherent skill exercised by the histopathologist in interpreting microscopical images, whilst making quantitization more accurate and reproducible. the system has been developed within a highly structured framework and will have applications in teaching and routine histological analysis. The value of artificial intelligence techniques in the wider issues of this area is discussed.

Artificial Intelligence

A menu-driven knowledge base browsing tool.

Conventional computer-assisted medical decision-making systems have had limited impact on routine clinical practice. This has stimulated an alternative approach to the utilization of medical knowledge bases. Centering on the storage and retrieval of medical information, it aims to provide clinicians with computerized medical reference systems. In this paper we describe the development of a prototype menu-driven browsing tool, which allows clinicians to browse through the contents of a knowledge base in a number of ways. Operations include interrogation via disease classes, names or attributes; hierarchical display of all or part of a disease profile; printing of a disease profile; construction of differential diagnosis lists and comparison of two diseases. We discuss how the use of a menu-driven interface can help to overcome some of the problems encountered with previous designs of medical reference systems.

Artificial Intelligence