Small polyps at endoluminal CT colonography are often seen but ignored by radiologists

Plumb, Andrew A., Fanshawe, Thomas R., Phillips, Peter, Mallett, Susan, Taylor, Stuart A., Helbren, Emma, Boone, Darren and Halligan, Steve (2015) Small polyps at endoluminal CT colonography are often seen but ignored by radiologists. American Journal of Roentgenology, 205 (4). W424-W431. Full text not available from this repository.

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Official URL: https://doi.org/10.2214/AJR.14.14093

Abstract

Objective: The objective of our study was to describe the characteristics of polyps viewed but then dismissed incorrectly by radiologists at endoluminal CT colonography (CTC), eye movements during these errors, and features provoking false-positive diagnoses.

Materials and methods: Forty-two radiologists viewed 30 endoluminal CTC videos, each depicting a polyp, while their eye movements were tracked. Half of the videos had computer-assisted detection (CAD), and half did not. Classification errors were defined when proven polyps were seen but dismissed. Eye movements during these errors and during correct polyp identifications were compared with multilevel modeling. Polyps were divided subsequently into “difficult to classify” and “easy to classify” using a classification error threshold of more than 15%. Polyp diameter, height, and subjective conspicuity and the proportion of time viewed were compared between groups.

Results: Eye tracking revealed that 97% of false-negative polyp diagnoses were nonetheless preceded by the reader observing the polyp. The difficult polyps were significantly smaller than the easy polyps (mean diameter, 5.4 vs 8.2 mm, respectively p = 0.014) and were subjectively less conspicuous (median score, 4 vs 2; p = 0.0032). Readers spent proportionally less time viewing difficult polyps than viewing easy polyps (29.0% of the time they were on-screen vs 42.6%, respectively; p = 0.01) regardless of the presence of CAD.

Conclusion: Even small and subjectively inconspicuous polyps attract reader gaze, but they are nonetheless ignored. These errors are made rapidly even with CAD. Efforts to improve reader performance at CTC should focus on decision making rather than detection alone.

Item Type: Article
Journal / Publication Title: American Journal of Roentgenology
Publisher: American Roentgen Ray Society
ISSN: 1546-3141
Departments: Health and Medical Sciences
Depositing User: Anna Lupton
Date Deposited: 07 Jun 2019 15:43
Last Modified: 25 Jul 2019 15:02
URI: http://insight.cumbria.ac.uk/id/eprint/4826

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