Bio-medical Ontologies Maintenance and Change Management

72 L. Stanescu, D. Dan Burdescu, and M. Brezovan
conventional X-rays and digital luminescent radiography modalities. The X-ray
films can be digitized with different tools [105].
The storage of medical images in digital format makes an easy task their
transferring from one device to another and enhances the achieving and manipulation
process, in a useful and novel way.
Medical image management plays now an important role in designing and implementing
medical information systems. It is needed to introduce new methods
for representation, manipulation and search for multimedia information. The development
of picture archiving and communications systems (PACS) created a
unified structure for management of acquisition, storing, communication and display
of image data, but they don’t provide enough flexibility in sharing and utilization
of information associated to image [105]. As a result, the solution to all
these problems is the development of database management systems that enhance
the management and complex querying of medical multimedia information. Using
these systems there is the possibility to integrate different medical informatics
systems that are geographically dispersed, lowering the costs and enhancing the
medical act. Managing and querying these large collections of medical images and
alphanumerical information is a difficult task. The most efficient way for solving
these problems is to have a multimedia database management system with the
following characteristics [48, 61]:
• Support for multimedia data types;
• Possibility to manage a large number of multimedia objects;
• Hierarchical storage management;
• Conventional database capabilities;
• Possibility to retrieve multimedia information considering attributes or characteristics
extracted from multimedia information and finding multimedia objects
that have these types of characteristics in common; this technique is called content-based
retrieval
Content-based visual retrieval can be implemented taking into consideration
primitive visual characteristics (color, texture, shape), logical characteristics
(object identity), or abstract characteristics (scene semantics). The easiest way
for implementation is to use primitive characteristics as color, texture and shape
[18, 23, 86].
1.1 A General Model for Information Retrieval
A general model for content-based retrieval is presented in figure 1.1 [60]. The
information from the database is first pre-processed to extract specific
characteristics and other semantic characteristics and then it is indexed based on
these things. For information retrieval, the user’s query is processed and the main
characteristics are extracted. These characteristics of the query are then compared
with the characteristics of each record in the database. In the end, the user will see
the information with the characteristics that are most closely to the query’s
characteristics.