Displaying chest X-ray by beamer or monitor: comparison of diagnostic accuracy for subtle abnormalities

The advent of beamer projection of radiological images raises the issue of whether such projection compromises diagnostic accuracy. The purpose of this study was to evaluate whether beamer projection of chest X-rays is inferior to monitor display.

We selected 53 chest X-rays with subtle abnormalities and 15 normal X-rays. The images were independently judged by a senior radiologist and a senior pulmonologist with a state-of-art computer monitor. We used their unanimous or consensus judgment as the reference test. Subsequently, four observers (one senior pulmonologist, one senior radiologist and one resident from each speciality) judged these X-rays on a standard clinical computer monitor and with beamer projection. We compared the number of correct results for each method.

Overall, the sensitivity and specificity did not differ between monitor and beamer projection. Separate analyses in senior and junior examiners suggested that senior examiners had a moderate loss of diagnostic accuracy (8% lower sensitivity, pp<0.05, and 6% lower specificity, p=ns) associated with the use of beamer projection, whereas juniors showed similar performance on both imaging modalities.

These initial data suggest that beamer projection may be associated with a small loss of diagnostic accuracy in specific subgroups of physicians. This finding illustrates the need for more extensive studies.