Picture archiving and communications systems: a study of reliability of orthodontic cephalometric analysis

The objectives of this study were to investigate the possibility of using a picture archiving and communications system (PACS) for basic chairside cephalometric analysis and to compare PACS with hand-tracing and on-screen digitization using a commercial program (Dolphin Imaging Plus Version 10.0). One hundred digital lateral cephalometric radiographs were selected and analysed using the Eastman analysis. Angular and linear measurements were recorded and a single operator traced each radiograph twice, using each of the following methods: PACS, hand-tracing, and Dolphin Imaging. The British Standards Institution Coefficient of Repeatability was used to investigate repeatability within each method and the Bland and Altman method to investigate systematic and random errors between methods. The PACS was more repeatable than Dolphin for measuring the angle between the upper incisors and the maxillary plane but was less repeatable than hand-tracing for measuring percentage lower anterior face height (LAFH). There were statistically significant systematic differences between PACS, hand-tracing, and Dolphin for measurement of lower incisor inclination. However, all three methods agreed, on average, and differences between methods were all within clinically acceptable limits. PACS was found to be clinically acceptable to be used chairside, without the need for hand-tracing or involvement of any orthodontic software. This offers the freedom to analyse digital cephalograms within a clinical area at the same appointment as when the digital radiograph is taken.