Computer-aided detection (CAD) for CT colonography: incremental benefit of observer training

¹ Department of Specialist Radiology, University College Hospital, Euston Road, London NW1 2BU
² Intestinal Imaging Centre, St. Mark's Hospital, Northwick Park, London HA1 3UJ
³ Medicsight PLC, Berkeley Square, London W1J 5AT, UK

	Abstract

The purpose of this study was to investigate the incremental effect of focused training on observer performance when using computer-assisted detection (CAD) software to interpret CT colonography (CTC). Six radiologists who were relatively inexperienced with CTC interpretation underwent 1 day of focused training before reading 20 patient datasets with the assistance of CAD software (ColonCAR 1.3, Medicsight PLC). Sensitivity, specificity and interpretation times were determined and compared with previous performance when reading the same datasets but without the benefit of focused training, using the binomial exact test and Wilcoxon's signed rank test. Per-polyp sensitivity improved after training by 18% overall (95% confidence interval (CI): 14–24%, p<0.001) and was greatest for polyps of 6–9 mm (26%, 95% CI: 18–34%, p<0.001). Absolute sensitivity was 23% (9–36%), 51% (33–71%) and 74% (44–100%) for polyps of 5 mm, 6–9 mm and 10 mm respectively. Specificity fell significantly after focused training (median of 5.5 false positives per 20 datasets (interquartile range (IQR): 4–6) post-training vs median of 2.5 (IQR: 1–5) pre-training, p = 0.03). Interpretation time also increased significantly after training (from a median of 9.3 min (IQR: 9.3–14.5 min) to a median of 17.1 min (IQR: 15.4–19.4 min), p = 0.03). In conclusion, one day of training increases observer polyp sensitivity when using CAD for CTC at the expense of increased reporting time and reduction in specificity.