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and the derived IE graph which is to lead to generating the analysed graph. A one-
pass generation-type parser carries out the syntactic analysis, at every step exam-
ining the characteristic description of the given vertex. If the vertex of the
analysed and the derived graphs is terminal, then their characteristic descriptions
are examined. However, if the vertex of the derived graph is non-terminal, then a
production is searched for, after the application of which the characteristic de-
scriptions are consistent. The numbers of productions used during the parsing
form the basis for classifying the recognised structure. This methodology makes
use of theoretical aspects of conducting the syntactic analysis for ETPL(k) gram-
mars, described in [3][16][18]. Due to the fact that in visualisations of coronary
vascularisation, we can distinguish three different types of topologies, characteris-
tic for these vessels, therefore, for each of the three types of topology, we can pro-
pose appropriate type of ETPL(k) graph grammar. Each grammar generates IE
graphs language, modelling particular types of coronary vascularisation. This rep-
resentation was then subjected to a detailed analysis, to find the places of morpho-
logical changes indicating occurrence of pathology. This operation consists of
several stages, and uses, among others context-free sequential grammars [11][20].
Next steps in the analysis on the example of coronary artery are shown in fig. 11.
Arteries with vertices ST
1
- RCA
2
and L_LAD
3
- LAD
6
represented by the
edges 15
of the IE graph have been subjected to the operation of the
straightening transformation [11], which allows to obtain the width diagrams of
the analyzed arteries, while preserving all their properties, including potential
changes in morphology. In addition, such representation allows to determine the
nature of the narrowing (concentric or eccentric). Concentric stenoses appear on a
cross-section as a uniform stricture of the whole artery and present symptoms
characteristic for a stable disturbance of heart rhythm, whereas eccentric stenoses
occur only on one vascular wall, and characterize an unstable angina pectoris [2].
Analysis of morphological changes was conducting based on the obtained width
diagrams and using context-free attributed grammars [11][20]. As a result of car-
ried out operations profiles of the analyzed coronary arteries with marked areas of
existing pathologies, together with the determination of the numerical values of
their advancement level were obtained (fig. 11.). Methodology presented above
was implemented sequentially to the individual sections of coronary vascularisa-
tion represented by the particular edges of the introduced graph representation.
ι
and 17
μ
5.5 Selected Results
In order to determine the operating efficiency of the proposed methods, a set of
test data, namely visualisations obtained during diagnostic examinations using 64-
slice spiral computed tomography was used. This set consisted of 20 complete
reconstructions of coronary vascularisation (table 2.) obtained during diagnostic
examinations of various patients, mainly suffering from coronary heart disease at
different progression stages. The test data also consisted of visualisations previ-
ously used to construct the grammar and the syntactic analyser. However, to avoid
analysing identical images, from the same sequences frames were selected that
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