The influence of monochrome liquid crystal displays with different resolutions on observer performance for the detection of pulmonary nodules

Purpose To assess the effect of monochrome liquid crystal displays (LCDs) with different resolutions on the detection performance of solitary pulmonary nodules. Materials and Methods By reviewing our hospital's picture archiving and communication system (PACS), 93 DR chest images were selected, including 55 without and 38 with solitary non-calcified pulmonary nodules. CT scans of the same patient served as the gold standard for the presence of a pulmonary nodule. These positive images were divided into two groups, A and B, according to the diameters of the nodules. Three high-, three mid- and three low-experienced radiologists interpreted these images with 2 mega pixel (MP), 3MP and 5MP monochrome LCDs, respectively. The readers were requested to rank each image using a five-point confidence level rating scale (1=definite absence, 2=probable absence, 3=indetermination, 4=probable presence, 5=definite presence), and the data were interpreted using receiver operating characteristic (ROC) analysis. Results When detecting the whole positive cases by the use of 2MP-, 3MP- and 5MP-LCD, the AUCs were 0.774, 0.784 and 0.816 for high-experienced radiologists, were 0.754, 0.764 and 0.768 for mid-experienced radiologists, and 0.695, 0.754 and 0.774 for low-experienced radiologists, respectively. When detecting the positive cases of Group A, the AUCs were 0.643, 0.686 and 0.739 for high-experienced radiologists, were 0.636, 0.682 and 0.717 for mid-experienced radiologists, and 0.623, 0.656 and 0.721 for low-experienced radiologists, respectively. When detecting the positive cases of Group B, the AUCs were 0.813, 0.832 and 0.846 for high-experienced radiologists, were 0.773, 0.824 and 0.838 for mid-experienced radiologists, and 0.763, 0.773 and 0.833 for low-experienced radiologists, respectively. However, there were no significant differences among different reading modalities. Conclusion For detecting pulmonary nodules, the observer performances with 2MP, 3MP and 5MP monochrome LCDs were comparable.