An evaluation of the errors in cephalometric measurements on scanned cephalometric images and conventional tracings

Abstract

The aim of this investigation was to compare the classic method of tracing by hand with a computerized method, where the lateral cephalograms were scanned at 300 dpi and digitized onscreen. The inter- and intra-observer errors were investigated for tracing and digitizing errors. Thirty lateral cephalograms were scanned into digital format at 300 dpi, displayed on a high-resolution monitor, and processed twice by two operators using Dolphin Imaging Software 9.0. The same radiographs were then traced and measured manually by the same two operators. Intraclass correlation coefficients (ICC) were used for detecting intra- and inter-rater agreement for each cephalometric variable. The results showed that each operator was consistent in the repeated measurements; all ICC were greater than or equal to 0.90 and none of the 95 per cent confidence limits on these ICC had a lower boundary less than 0.84. Inter-rater agreement also showed correlation coefficients greater than 0.75. The angles, maxillary height, maxillary depth, y-axis, FMA, and nasolabial, and the distance N perpendicular point A had a wider reliability interval and lower correlation than the other parameters tested. The findings demonstrated that the use of computer software for cephalometric analysis carried out on scanned images does not increase the measurement error when compared with hand tracing.

Reproducibility of measurements in tablet-assisted, PC-aided, and manual cephalometric analysis

“…9,20 To evaluate reproducibility for each cephalometric parameter, the agreement between the value derived from NemoCeph, that given by SmileCeph, and that measured manually was assessed with the ICC. 4,5,9,20 Agreement was rated as low for an ICC #lower than 0.75. Conversely, an ICC .…”

“…In computerized cephalometric analysis, once the requested landmarks have been entered, the software automatically calculates distances and angles, thus eliminating errors that may occur in hand tracing when drawing lines with a ruler and measuring angles with a protractor. 5,7,8 Furthermore, collecting computer-assisted cephalometrics is less time-consuming than manual tracing, 3,9 and it allows the user to obtain several analyses at a time. 6 In addition, digital archiving overcomes the problem of film deterioration.…”

“…6 In addition, digital archiving overcomes the problem of film deterioration. 6,9 Earlier studies have assessed the reproducibility of measurements in manual versus computer-aided cephalometric analysis. [3][4][5][6][8][9][10][11][12][13][14][15][16][17][18][19][20] However, as new programs for computerized cephalometry are continuously launched, their accuracy needs to be validated against that of previously marketed softwares and against traditional hand tracing.…”

“…Conversely, with all the other marketed softwares points are digitized by means of a mouse-driven cursor. As landmark identification has been reported to be the main source of error in cephalometric analysis, 9,21 it seemed worth verifying whether digitizing the points directly on the tablet touch screen is a reliable method. With this objective, the reproducibility of cephalometric measurements provided by the tablet, by marketed software for personal computers (PCs), and by hand-tracing was assessed.…”

Quantitative Evaluation of Patient Movement during Simulated Acquisition of Cephalometric Radiographs

“…There were studies on the cephalometric analysis comparing between the conventional and digital radiographs using CR images, 12 scanned images of conventional films, 13,14 and a slit-beam type machine with a skull, 15 a cadaver, 16 or a phantom. 9 Although there were a few studies using the slit-beam type of cephalometric equipment, 17,18 they did not consider the possibility of the image distortion due to the patients' movements.…”