Characterizing virtual slide exploration through the use of 'search maps'

Currently very little is known about the process by which pathologists arrive at a diagnosis on a case. This process is an integration of the pathologist's slide exploration strategy, perceptual information gathering and cognitive decision making. We have developed a methodology to statically represent the pathologists' dynamic visual search of digital slides by creating a representation of visual sampling called 'search maps'. In these maps slide exploration is divided into three parts, according to the magnification range used. In other words, areas explored at low magnification (<=4x), medium magnification (>4x-10x) and high magnification (>10x-20x) are represented separately. Moreover, representation using the 'search maps' allows for quantitative analysis and pairwise comparison of slide exploration strategy. In this paper we have compared the search maps of experienced pathologists and those of Pathology residents. Our goal was to understand how search differs between the experts and the trainees.