It is impossible to imagine the up to date medicine without modern diagnostic equipment employment. Though image methods have got routine character there exists a set of problems in their application. In the first place it is due to the fact that physicians have to work (to deal) with semistructured and non-formalized information. In addition, its volume itself is constantly increasing due to appearance of new methods and technologies for patients examining.

The ultrasound examination domain is not an exception. The appearance of new devices or improving of old scanners does not simplify, but often complicates the process of physician thinking, given the fact that he is forced to analyze a larger number of data. Typically, such a situation reduces accuracy and increases the time period required for determining the diagnosis. It is obvious that the development of informatics tools in the framework of diagnostic methodology would solve the appeared problems.

A group of researchers from the Institute of Mathematics and Computer Science of A.S.M. under the guidance of c.m. Constantin Gaindric and dr.h. Svetlana Cojocaru, for a long time elaborates a decision support system (DSS) - SonaRes, aimed at the field of ultrasound examination. How does it work? As it is known, a consecutivity of loss of information accuracy is characteristic of the process of ultrasound investigation: the analogical signal emitted by probe is converted into digital one, which in its turn, serves as a source for image building. It is accepted (in a subjective way) by the operator, obtaining as a result an interpretation in written form, more or less proper to this image, depending on the experience and qualifications of the operator. One of the aims pursued by the team of specialists when designing the system SonaRes consists namely in reducing that loss of information. Proceeding from the experience of employment of other systems of this kind, their beneficial aspects have been taken and developed, supplementing them with new qualities.

SonaRes system consists of the following components: a module of knowledges acquisition and their validation; integrated base (of knowledge, images, annotations, reports of investigations); module of image processing; tools for the investigation process support, including the user interface; generator of investigation reports.

The knowledges acquisition process and their subsequent formalization is considered to be the key moment in the process of creation of any decision support system. To obtain a well structured description of the problem domain, the "rigid" schemes of knowledge representation are usually chosen. Most frequently the problem domain is represented in a form of a tree or as a semantic network.

The physician-diagnostician, at which the system SonaRes is destined, has his own investigative habits, his way of thinking, specific knowledges, which do not correspond to "rigid" schemes and can lead to mistakes in diagnosis. Moreover, he might even refuse to use this useful tool though aware of the quality of diagnosis and the reports generated by the system.

To resolve these problems the team of researchers from the Institute of Mathematics and Computer Science of A.S.M. (Iulian Secrieru - the researcher, Daniel Verlan - the engineer etc.) had proposed and realized the principles, algorithms and new techniques for handling structured knowledges. On the basis of these approaches there was set the principle of usage of an alternative representation of the knowledge base, which at the stage of expert's knowledge acquisition and formalization was retained as a decision tree. Subsequently this representation of the knowledge base has been called matrix-like, because each conclusion may be described as a vector and all possible conclusions form a matrix.

We will specify that the matrix representation of the knowledge base does not replace the tree one, but supplements it. Applying the alternative representation, there has been developed such an interface for the system SonaRes, which combines different methods of investigation (detailed "step by step", starting from the presumed pathology, etc.). However, the system allows an effective transition from one mode of investigation to another. In other words, physicians-sonologists can benefit now from the tools that meets their daily practice, adapts to their preferences and style of work - the fact which ultimately leads to rising of the examination quality.

Tatiana Rotaru,
Press service of the A.S.M.