Precision of identifying cephalometric landmarks with cone beam computed tomography in vivo (original) (raw)
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Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology, 2009
To evaluate reliability in 3-dimensional (3D) landmark identification using cone-beam computerized tomography (CBCT).Twelve presurgery CBCTs were randomly selected from 159 orthognathic surgery patients. Three observers independently repeated 3 times the identification of 30 landmarks in the sagittal, coronal, and axial slices. A mixed-effects analysis of variance model estimated the intraclass correlations (ICC) and assessed systematic bias.The ICC was >0.9 for 86% of intraobserver assessments and 66% of interobserver assessments. Only 1% of intraobserver and 3% of interobserver coefficients were <0.45. The systematic difference among observers was greater in X and Z than in Y dimensions, but the maximum mean difference was quite small.Overall, the intra- and interobserver reliability was excellent. Three-dimensional landmark identification using CBCT can offer consistent and reproducible data if a protocol for operator training and calibration is followed. This is particularly important for landmarks not easily specified in all 3 planes of space.
Evaluation of cephalometric landmark identification on CBCT multiplanar and 3D reconstructions
The Angle Orthodontist, 2015
Objective: To evaluate the reliability of three-dimensional (3D) landmark identification in conebeam computed tomography (CBCT) using two different visualization techniques. Materials and Methods: Twelve CBCT images were randomly selected. Three observers independently repeated three times the identification of 30 landmarks using 3D reconstructions and 28 landmarks using multiplanar views. The values of the coordinates X, Y, and Z of each point were obtained and the intraclass correlation coefficient (ICC) was calculated. Results: The ICC of the 3D visualization was rated .0.90 in 67.76% and 45.56%, and #0.45 in 13.33% and 14.46% of the intraobserver and interobserver assessments, respectively. The ICC of the multiplanar visualization was rated .0.90 in 82.16% and 78.56% and #0.45 in only 16.7% and 8.33% of the intraobserver and interobserver assessments, respectively. An individual landmark classification was done according to ICC values. Conclusions: The frequency of highly reliable values was greater for multiplanar than 3D reconstructions. Overall, lower reliability was found for points on the condyle and higher reliability for those on the midsagittal plane. Depending on the anatomic region, the observer must choose the most reliable type of image visualization.
Dentomaxillofacial Radiology, 2009
Objectives: To compare reliability for landmark identification on patient images from three-dimensional (3D) cone beam CT (CBCT) and digital two-dimensional (2D) lateral cephalograms. Methods: Ten lateral cephalometric digital radiographs and their corresponding CBCT images were randomly selected. 27 observers digitally identified 27 landmarks in both modes. The x-and y-coordinates for each landmark, indicating the horizontal and vertical positions, were analysed for interobserver reliability by comparing each measurement to the best estimate of the true value. Intraobserver reliability was also assessed. Linear models and intraclass correlation coefficients (ICCs) were used for analyses. Results: For interobserver reliability, the following locations were farther from the best estimate for 2D than 3D: x-location in subspinale (A-point), anterior tip of the nasal spine (ANS), L1 lingual gingival border and L1 root; y-location in porion, ramus point and orbitale; x-and y-locations in basion, condylion, midramus, sigmoid notch and U6 occlusal. 3D y-locations were farther in the gonion, L1 tip, sella and U1 tip. For intraobserver reliability, 2D locations were farther in y-locations in orbitale and sigmoid notch, and both xand y-locations in basion. 3D locations were farther in the x-location in U1 labial gingival border and y-locations in L1 tip, L6 occlusal, menton and sella. For intraobserver ICCs, greater variations in 2D than 3D included: A-point, ANS, midramus, orbitale, ramus point, sigmoid notch and U1 root. Conclusions: 3D imaging, as in CBCT, allows for overall improved interobserver and intraobserver reliability in certain landmarks in vivo when compared with two-dimensional images.
Dentomaxillofacial Radiology, 2009
Objectives: To compare reliability for landmark identification on patient images from three-dimensional (3D) cone beam CT (CBCT) and digital two-dimensional (2D) lateral cephalograms. Methods: Ten lateral cephalometric digital radiographs and their corresponding CBCT images were randomly selected. 27 observers digitally identified 27 landmarks in both modes. The x-and y-coordinates for each landmark, indicating the horizontal and vertical positions, were analysed for interobserver reliability by comparing each measurement to the best estimate of the true value. Intraobserver reliability was also assessed. Linear models and intraclass correlation coefficients (ICCs) were used for analyses. Results: For interobserver reliability, the following locations were farther from the best estimate for 2D than 3D: x-location in subspinale (A-point), anterior tip of the nasal spine (ANS), L1 lingual gingival border and L1 root; y-location in porion, ramus point and orbitale; x-and y-locations in basion, condylion, midramus, sigmoid notch and U6 occlusal. 3D y-locations were farther in the gonion, L1 tip, sella and U1 tip. For intraobserver reliability, 2D locations were farther in y-locations in orbitale and sigmoid notch, and both xand y-locations in basion. 3D locations were farther in the x-location in U1 labial gingival border and y-locations in L1 tip, L6 occlusal, menton and sella. For intraobserver ICCs, greater variations in 2D than 3D included: A-point, ANS, midramus, orbitale, ramus point, sigmoid notch and U1 root. Conclusions: 3D imaging, as in CBCT, allows for overall improved interobserver and intraobserver reliability in certain landmarks in vivo when compared with two-dimensional images.
Medicina Oral Patología Oral y Cirugia Bucal, 2012
Objectives: Cone Beam Computerized Tomography (CBCT) allows the possibility of modifying some of the diagnostic tools used in orthodontics, such as cephalometry. The first step must be to study the characteristics of these devices in terms of accuracy and reliability of the most commonly used landmarks. The aims were 1-To assess intra and inter-observer reliability in the location of anatomical landmarks belonging to hard tissues of the skull in images taken with a CBCT device, 2-To determine which of those landmarks are more vs. less reliable and 3-To introduce planes of reference so as to create cephalometric analyses appropriated to the 3D reality. Study design: Fifteen patients who had a CBCT (i-CAT®) as a diagnostic register were selected. To assess the reproducibility on landmark location and the differences in the measurements of two observers at different times, 41 landmarks were defined on the three spatial axes (X,Y,Z) and located. 3.690 measurements were taken and, as each determination has 3 coordinates, 11.070 data were processed with SPSS® statistical package. To discover the reproducibility of the method on landmark location, an ANOVA was undertaken using two variation factors: time (t1, t2 and t3) and observer (Ob1 and Ob2) for each axis (X, Y and Z) and landmark. The order of the CBCT scans submitted to the observers (Ob1, Ob2) at t1, t2, and t3, were different and randomly allocated. Multiple compari
Cephalometric measurements from 3D reconstructed images compared with conventional 2D images
The Angle Orthodontist, 2011
Objective: To assess whether the values of different measurements taken on three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) are comparable with those taken on two-dimensional (2D) images from conventional lateral cephalometric radiographs (LCRs) and to examine if there are differences between the different types of CBCT software when taking those measurements. Material and Methods: Eight patients were selected who had both an LRC and a CBCT. The 3D reconstructions of each patient in the CBCT were evaluated using two different software packages, NemoCeph 3D and InVivo5. An observer took 10 angular and 3 linear measurements on each of the three types of record on two different occasions. Results: Intraobserver reliability was high except for the mandibular plane and facial cone (from the LCR), the Na-Ans distance (using NemoCeph 3D), and facial cone and the Ans-Me distance (using InVivo5). No statistically significant differences were found for the angular and linear measurements between the LCRs and the CBCTs for any measurement, and the correlation levels were high for all measurements. Conclusion: No statistically significant differences were found between the angular and linear measurements taken with the LCR and those taken with the CBCT. Neither were there any statistically significant differences between the angular or linear measurements using the two CBCT software packages. (Angle Orthod. 2011;81:856-864.)
A new method for improved standardisation in three-dimensional computed tomography cephalometry
Computer Methods in Biomechanics and Biomedical Engineering, 2010
To refer to or to cite this work, please use the citation to the published version: Van Cauter, S., Okkerse, W., Brijs, G., De Beule, M., Braem, M. and Verhegghe, B. (2010) 'A new method for improved standardisation in three-dimensional computed tomography cephalometry', Computer Methods in Biomechanics and Biomedical Engineering, 13: 1, 59-69,
American Journal of Orthodontics and Dentofacial Orthopedics, 2007
As orthodontic practice moves toward 3-dimensional cephalometric analyses, a solution is required to ensure sustained availability of well-established projected treatment outcomes based on 2-dimensional analyses. This ex-vivo study was conducted to compare the accuracy of linear measurements made on photostimulable phosphor cephalograms with 3 methods for simulating lateral cephalograms with cone-beam computed tomography (CBCT). Methods: The linear distances between anatomical landmarks on dentate dry human skulls were measured by observers using digital calipers for S-N, Ba-N, M-N, ANS-N, ANS-PNS, Pog-Go, Go-M, Po-Or, and Go-Co. The skulls were imaged with CBCT with a single 360°rotation, producing 306 basis images and achieving 0.4 mm isotrophic voxel resolution on volumetric reconstruction for making ray-sum reconstructed cephalograms. Two other cephalogram approaches were used with the CBCT system-a single transmission image generated as a scout image designed to check patient positioning before CBCT, and a single-frame lateral basis image. Conventional digital lateral cephalograms (LCs) were acquired with the photostimulable phosphor system. Images were imported into a cephalometric analysis program (Dolphin Imaging Cephalometric and Tracing Software, Chatsworth, Calif) to compute the included linear measurements. Analyses were repeated 3 times and statistically compared with measured anatomic truth with ANOVA (P Յ.05). The intraclass correlation coefficient was determined as an index of intra-and interobserver reliability. Results: The intraclass correlation coefficient for the LCs was significantly less than for the measured anatomic truth and for all CBCT-derived images. CBCT images either produced with individual frames or reconstructed from the volumetric data set were accurate for all measurements except Pog-Go and Go-M. CBCT scout images had the second highest accuracy for all measurements except Pog-Go, Go-M, and Go-Co. Conventional LCs had the least accuracy; they were accurate only for Po-Or and ANS-N. Conclusions: CBCT-derived 2-dimensional LCs proved to be more accurate than LCs for most linear measurements calculated in the sagittal plane. No advantage was found over single-frame basis images in using ray-sum generated cephalograms from the CBCT volumetric data set. (Am J Orthod Dentofacial Orthop 2007;132:550-60) c Private practice, Phoenix, Ariz. d Professor, Fig 1. Selection of CBCT basis images: 4 basis image frames from 306 that comprising primary data for iCAT CBCT full scan. A, Frame 1, first basis projection image; B, frame 75; C, frame 152; D, frame 306, last basis image.
3D cephalometric analysis obtained from computed tomography. Review of the literature
Annali di stomatologia, 2011
The aim of this systematic review is to estimate accuracy and reproducibility of craniometric measurements and reliability of landmarks identified with computed tomography (CT) techniques in 3D cephalometric analysis. Computerized and manual searches were conducted up to 2011 for studies that addressed these objectives. The selection criteria were: (1) the use of human specimen; (2) the comparison between 2D and 3D cephalometric analysis; (3) the assessment of accuracy, reproducibility of measurements and reliability of landmark identification with CT images compared with two-dimensional conventional radiographs. The Cochrane Handbook for Systematic Reviews of Interventions was used as the guideline for this article. Twenty-seven articles met the inclusion criteria. Most of them demonstrated high measurements accuracy and reproducibility, and landmarks reliability, but their cephalometric analysis methodology varied widely. These differencies among the studies in making measurements...