Gaze tracking is a common method to assess perceptual processes when reading medical images. However, little
attention has yet been paid to multi-slice images. The present study examines the gaze data of four experienced radiologists reading 15 cranial Computer Tomography scans (CCT), five of which contain lesions. The participants navigated freely through the slices, while their eye position was tracked. Participants' visual search performance was
examined in terms of: time per case, scrolling pattern including the number of runs through each case and number of oscillations within each case, fixation duration, time to first fixate a lesion and the initial dwell time on a lesion. The
results of the study indicate that performance and reading strategy differ between radiologists. The greatest behavioral
differences occurred between the two readers, who performed best. One of them, participant 4, showed extremely short periods of inspection, few oscillations between the slices, short initial dwells on lesions and short time to first fixation,
whereas participant 2 performed equally as well, but took longer to read individual cases, went through the slices with many more oscillations, showed longer time to first fixation and initial dwell times on lesions. The behavior displayed by participant 4 is consistent with expert behavior reading 2-dimensional images. In contrast, participant 2's behavior resembles that of a novice, namely because of the systematic search pattern employed. The results hint that expertise may be characterized by various and diverse strategies.