Effects of monitor size on accuracy and time needed to detect cephalometric radiographs landmarks

The question whether monitor size might affect routinely performed medical analysis and measurements tasks is especially topical, given the competing pressures in the market towards big displays and the increasing diffusion of small sized, mobile platforms. The aim of this study was to investigate if the accuracy of landmarks detection on lateral cephalometric radiographs and the time needed to detect them are affected by monitor size.A software tool was developed to allow six experts to locate 22 landmarks in 15 X-rays in three different monitor sizes: 19″, 17″ and a 12″ tablet. The measures were repeated two times in different sessions in order to evaluate the impact of the monitor size on the accuracy or repeatability of cephalometric landmarking. The Intraclass Correlation Coefficients (ICCs), as a measure of inter-observer reliability, showed that for each landmark there was an excellent agreement between the users. Friedman’s test was used in order to accept or reject the “null” hypothesis.We found that the reproducibility of cephalometric landmarking on screen is not affected, for most landmarks, by commercial grade high resolution LCD screen sizes ranging from 12″ to 19″; there is an average gain of about 1 min in the overall time spent performing a whole cephalometric analysis with 22 landmarks in the 19″ display, but it is not such to justify the choice of a bigger size display.

► Cephalometric landmarking overall accuracy is alike in displays from 12″ to 19″.
► Cephalometric landmarking can be performed effectively on portable Tablet PC.
► The 1 min average gain in the 19″ size is not such to justify bigger displays.