The assessment of stroke multidimensional CT and MR imaging using eye movement analysis: does modality preference enhance observer performance?

Abstract

Additional Information:• Copyright 2010 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. This paper can also be found ABSTRACTAlthough CT and MR imaging is now commonplace in the radiology department, few studies have examined complex interpretative tasks such as the reading of multidimensional brain CT or MRI scans from the observer performance perspective, especially with reference to Stroke. Modality performance studies have demonstrated a similar sensitivity of less than 50% for both conventional modalities, with neither modality proving superior to the other in Stroke observer performance tasks (Mohr, 1995;Lansberg, 2000;Wintermark, 2007). Visual search studies have not extensively explored stroke imaging and an in-depth, comparative eye-movement study between CT and MRI has not yet been conducted. A computer-based, eye-tracking study was designed to assess diagnostic accuracy and interpretation in stroke CT and MR imagery. Forty eight predetermined clinical cases, with five images per case, were presented to participants (novices, trainees and radiologists; n=28). The presence or absence of abnormalities was rated on a four-point Likert scale and their locations reported. Results highlight differences in visual search patterns amongst novice, trainee and expert observers; the most marked differences occurred between novice readers and experts. In terms of modality differences; novice and expert readers spent longer appraising CT images than MR, compared with trainees, who spent longer appraising MR than CT images. Image analysis trends did not appear to differ between modalities, but time spent within clinical images, accuracy and relative confidence performing the task did differ between CT and MR reader groups. To-date few studies have explored observer performance in neuroradiology and the present study examines multi-slice image appraisal by comparing matched pairs of CT and MRI Stroke cases.

Review of prospects and challenges of eye tracking in volumetric imaging

“…In two experiments, the radiologists were presented with five consecutive slices of MRI and CT cases, but they were only able to scroll in the forward direction, meaning that once they had chosen to scroll on, they were not able to return to a previous slice. 50,51 Four studies chose to present CT colonography fly-through videos rather than individual slices, 46,47,53,61 which means that all radiologists who took part in the study saw the slices being presented at the same pace and were unable to adjust the rate or scroll back to a location that was presented earlier.…”

“…48,54 Conversely, fixations that cover multiple slices were presumably not a problem in experiments where radiologists were only allowed to scroll in one direction, as the time they spent on each slice was relatively long to avoid missing something that they could not get back to. 50,51 Five of the studies where scrolling was allowed, distinguished between fixations and saccades, 49,52,56-58 but did not explicitly state how fixations were scored. For the majority of them, the relatively short fixation durations that are reported suggest that fixations were calculated per individual slice.…”

“…The studies that dealt with volumetric imaging material [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] used images suitable for a three-dimensional representation of the human body, however, the presentation of stimulus material differed between them. Eight of the studies presented all slices of a multislice case and allowed radiologists to scroll freely through these stacks; 49,52,[55][56][57][58][59][60] thus, radiologists could scroll back and forth for as long as they wanted to and also determine the pace of their movement through the stack.…”

“…By contrast, only a limited number of studies have aimed at shedding light on the relationship between visual search, perception, cognition, and performance in the context of volumetric images: five experiments have explored radiologists' reading strategies of stimulus material that was acquired by a volumetric imaging technique, [45][46][47][48][49] while five other studies looked at the influence of expertise on gaze behavior, [50][51][52][53][54] four explored the implications of different workstation configurations on gaze, [55][56][57][58][59] and one study examined the presence of inattentional blindness in the interpretation of chest CT cases. 60 Finally, one study looked at the visual search characteristics of readers when using computer-aided detection in CT colonography presented in the fly through mode.…”

Incidental Findings on Brain MRI: Insight from HUNT MRI - A General Population Study

“…The reasons are manifold, but include: 1) The HUNT MRI scan protocol: same comprehensive clinical protocol used for all participants; 2) All images were read by two senior neuroradiologists [17][18][19]; and 3) Inclusion of middle aged subjects, as prevalence of cerebrovascular disease and intracranial tumors increases with age [4,10].…”