Detectability of Catheters on Bedside Chest Radiographs: Comparison between Liquid Crystal Display and High-Resolution Cathode-Ray Tube Monitors

Abstract

To compare observer performance with a flat-panel liquid crystal display (LCD) monitor and with a high-resolution gray-scale cathode-ray tube (CRT) monitor in the detection of simulated support catheters on bedside chest radiographs. The ethics committee did not require approval or patient informed consent when this study began. Because of a change in regulations, before images were acquired the nature of the study and procedures were explained to patients or their relatives, and consent was then obtained. A total of 131 catheter fragments (12-14 per radiograph) were superimposed over 10 anteroposterior bedside chest radiographs obtained with storage phosphor technology. Images were displayed on an LCD monitor (1536 x 2048 matrix) and a CRT monitor (2048 x 2560 matrix). Five radiologists independently located the catheter fragments and rated their confidence in detection with bright and subdued ambient light. A two-way analysis of variance and the Friedman test were used for statistical analysis. There was no significant difference for either display type with respect to correctly detected catheter fragments (mean sensitivity, 56.6% and 56.0% for the CRT and the LCD monitors, respectively, with bright light and 61.2% for both monitors with subdued light). With both display types, detection rate with bright light decreased significantly (P < .05). False-positive rates and confidence ratings were not significantly affected by monitor type or ambient light. In a study with simulation of clinical conditions, performance of the LCD monitor and high-resolution CRT monitor for detection of support catheters on bedside chest radiographs was equivalent. With both displays, detection performance was equally reduced with bright ambient light.