Optimizing viewing procedures of breast tomosynthesis image volumes using eye tracking combined with a free response human observer study

Abstract

The purpose of this study was to evaluate four different viewing procedures as part of improving viewing conditions of breast tomosynthesis (BT) image volumes. The procedures consisted of free scroll volume browsing, and a combination of initial cine loops at three different frame rates (9, 14 and 25 fps) terminated upon request followed by free scroll volume browsing. Fifty-five normal BT image volumes in MLO view were collected. In these, simulated lesions (20 masses and 20 clusters of microcalcifications) were randomly inserted, creating four unique image sets for each procedure. Four readers interpreted the cases in a random order. Their task was to locate a lesion, mark and assign a five level confidence scale. The diagnostic accuracy was analyzed using Jackknife Free Receiver Operating Characteristics (JAFROC). Time efficiency and visual search behavior were also investigated using eye tracking. The results indicate that there was no statistically significant difference in JAFROC FOM between the different viewing procedures, however the medium cine loop speed seemed to be the preferred viewing procedure in terms of total analyze time and dwell time.

Review of prospects and challenges of eye tracking in volumetric imaging

“…For the majority of them, the relatively short fixation durations that are reported suggest that fixations were calculated per individual slice. 49,[56][57][58] Interestingly, six of the studies omitted the calculation of fixations and saccades altogether [45][46][47]60,61 and used raw data instead. While there is no definite right or wrong in the detection of events in eye tracking data, there are problems associated with calculating fixations per slice and the use of raw data: as aforementioned, the use of raw data does not account for saccadic suppression and for this reason, samples are included in the analysis that do not represent the intake of visual information.…”

“…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.…”

“…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. 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.…”

“…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.…”

Digital mammography and tomosynthesis for breast cancer diagnosis

“…No general conclusion on which algorithm is the better one has yet been reached. From the reconstructed 3D volume, individual thin slices can be studied, either as a movie (in a cine-loop) or stepped through manually one-by-one [44]. Each slice image contains much less of the superimposed normal tissue than the conventional twodimensional (2D) image.…”