Jeffery, N, Teather D, & Teather B,A
Abstract
The research presented in this paper relates to the development and
evaluation of visual cues for accessing and comparing medical images of
patients with a particular disease (pathology). The methodology utilises
a scatter plot constructed from Multiple Correspondence Analysis to
provide an overview of the variability in appearance of cases of a
pathology. We investigate the extent to which the MCA scatter plot / map
can serve as a model of psychological similarity and typicality. It is
postulated that psychological similarity is captured in the spatial
relations of items in the plot. The MCA scatter plot aims to provide an
intuitive way of conceptualising similarity relations in that two stimuli
are similar psychologically if they appear close together in the
similarity space. It is also posited that the psychological notion of
the typicality of cases within a disease may be visualised as the
distance of any case from the centre of this map. It should also be
possible to provide information using these scatter plots relating to the
relative positions of cases in overlapping pathologies to allow for easy
identification of problem cases (i.e. ones that lie in the region
of overlap) and to assist in the categorisation of new additions to the
archive (i.e. if a case is more similar to a prototype of one disease
than the other then it may well be categorised as being a member of the
first disease). The approach adopted for developing this plot and the
derivation of the associated measures of typicality and similarity
are described. A series of evaluations designed to test the accuracy and
validity of the information provided in the plot and to assess whether
such a plot could provide a useful vehicle for assisting computer based
training are also described.