Automated cephalometry: System performance reliability using landmark-dependent criteria

Abstract

Objective: The purpose of the present study was to evaluate reliability of system that performsautomatic recognition of anatomic landmarks and adjacent structures on lateral cephalogramsusing landmark-dependent criteria unique to each landmark. Materials and Methods: To evaluate the reliability of the system, the system was used to examine65 lateral cephalograms. The area of each system-identified anatomic structure surrounding thelandmark and the position of each system-identified landmark were compared with norms using confidence ellipses with -.01, which were derived from the scattergrams of 100 estimatesobtained according to the method reported by Baumrind and Frantz. When the system-identifiedarea overlapped with the norm area, anatomic structure recognition was considered successful.In addition, when the system-identified point was located within the norm area, landmark identificationwas considered successful. Based on these judgment criteria, success rates were calculated for all landmarks.Results: The system successfully identified all specified anatomic structures in all the imagesand determined the positions of the landmarks with a mean success rate of 88% (range, 77%-100%).Conclusion: With the incorporation of the rational assessment criteria provided by confidenceellipses, the proposed system was confirmed to be reliable. (Angle Orthod. 2009;79:1037-1046. © 2009 by The EH Angle Education and Research Foundation, Inc.