Korean J Orthod.  2018 Sep;48(5):292-303. 10.4041/kjod.2018.48.5.292.

Accuracy of three-dimensional cephalograms generated using a biplanar imaging system

Affiliations
  • 1Department of Orthodontics, School of Dentistry, Chonnam National University, Gwangju, Korea. ortholkm@chonnam.ac.kr
  • 2Department of Radiology, School of Dentistry, Chonnam National University, Gwangju, Korea.

Abstract


OBJECTIVE
Biplanar imaging systems allow for simultaneous acquisition of lateral and frontal cephalograms. The purpose of this study was to compare measurements recorded on three-dimensional (3D) cephalograms constructed from two-dimensional conventional radiographs and biplanar radiographs generated using a new biplanar imaging system with those recorded on cone-beam computed tomography (CBCT)-generated cephalograms in order to evaluate the accuracy of the 3D cephalograms generated using the biplanar imaging system.
METHODS
Three sets of lateral and frontal radiographs of 15 human dry skulls with prominent facial asymmetry were obtained using conventional radiography, the biplanar imaging system, and CBCT. To minimize errors in the construction of 3D cephalograms, fiducial markers were attached to anatomical landmarks prior to the acquisition of radiographs. Using the 3D Cephâ„¢ program, 3D cephalograms were constructed from the images obtained using the biplanar imaging system (3D cephbiplanar), conventional radiography (3D cephconv), and CBCT (3D cephcbct). A total of 34 measurements were obtained compared among the three image sets using paired t-tests and Bland-Altman plotting.
RESULTS
There were no statistically significant differences between the 3D cephbiplanar and 3D cephcbct measurements. In addition, with the exception of one measurement, there were no significant differences between the 3D cephcbct and 3D cephconv measurements. However, the values obtained from 3D cephconv showed larger deviations than those obtained from 3D cephbiplanar.
CONCLUSIONS
The results of this study suggest that the new biplanar imaging system enables the construction of accurate 3D cephalograms and could be a useful alternative to conventional radiography.

Keyword

Three-dimensional cephalogram; Cephalometry; Biplanar radiography; Cone-beam computed tomography

MeSH Terms

Cephalometry
Cone-Beam Computed Tomography
Facial Asymmetry
Fiducial Markers
Humans
Radiography
Skull

Figure

  • Figure 1 Dry human skull used in this study. The risk of errors during the process of three-dimensional cephalogram construction is minimized by the attachment of titanium fiducial markers to anatomical landmarks prior to the acquisition of radiographs. Description of landmarks are shown in the Table 1.

  • Figure 2 The biplanar imaging system used in this study. Two instrumentariums were positioned at a 90° angle and two arrays of X-ray beams were simultaneously projected toward the subject with the head posture remaining identical for both lateral and frontal cephalogram acquisition.

  • Figure 3 The three-dimensional (3D) Ceph™ program (Department of Orthodontics, University of Chicago, IL, USA) used in this study. A and B, Input of lateral and frontal cephalograms into the 3D Ceph™ program. C, Landmark correction using vector intercept with manual or averaging algorithm in the 3D Aligner™ program (Department of Orthodontics, University of Illinois at Chicago, Chicago, IL, USA). D, Generation of a three-dimensional cephalometric image using the “create 3D frame” function and measurement output using the “3D log” function in the program.

  • Figure 4 Bland–Altman plots for the comparison of three-dimensional (3D) cephalograms constructed from biplanar radiographs and cone-beam computed tomography (CBCT) images. The x-axis shows the average measurements obtained from biplanar cephalograms and CBCT-generated cephalograms, whereas the y-axis represents differences in measurements between the two image sets. The red line represents standard deviations and the blue line represents the upper and lower limits of agreement. A, Width measurements; B, depth measurements; C, oblique measurements; D, height measurements. Descriptions of landmarks are shown in Figure 1 and Table 1.


Reference

1. Bergersen EO. Enlargement and distortion in cephalometric radiography: compensation tables for linear measurements. Angle Orthod. 1980; 50:230–244.
2. Ahlqvist J, Eliasson S, Welander U. The cephalometric projection. Part II. Principles of image distortion in cephalography. Dentomaxillofac Radiol. 1983; 12:101–108.
3. Jung PK, Lee GC, Moon CH. Comparison of cone-beam computed tomography cephalometric measurements using a midsagittal projection and conventional two-dimensional cephalometric measurements. Korean J Orthod. 2015; 45:282–288.
Article
4. Farman AG. ALARA still applies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2005; 100:395–397.
Article
5. American Dental Association Council on Scientific Affairs. The use of cone-beam computed tomography in dentistry: an advisory statement from the American Dental Association Council on Scientific Affairs. J Am Dent Assoc. 2012; 143:899–902.
6. American Academy of Oral and Maxillofacial Radiology. Clinical recommendations regarding use of cone beam computed tomography in orthodontics. [corrected]. Position statement by the American Academy of Oral and Maxillofacial Radiology. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013; 116:238–257.
7. Abdelkarim AA. Appropriate use of ionizing radiation in orthodontic practice and research. Am J Orthod Dentofacial Orthop. 2015; 147:166–168.
Article
8. Grayson B, Cutting C, Bookstein FL, Kim H, McCarthy JG. The three-dimensional cephalogram: Theory, techniques, and clinical application. Am J Orthod Dentofacial Orthop. 1988; 94:327–337.
Article
9. Brown T, Abbott AH. Computer-assisted location of reference points in three dimensions for radiographic cephalometry. Am J Orthod Dentofacial Orthop. 1989; 95:490–498.
Article
10. Trocmé MC, Sather AH, An KN. A biplanar cephalometric stereoradiography technique. Am J Orthod Dentofacial Orthop. 1990; 98:168–175.
Article
11. Bookstein FL, Grayson B, Cutting CB, Kim HC, McCarthy JG. Landmarks in three dimensions: reconstruction from cephalograms versus direct observation. Am J Orthod Dentofacial Orthop. 1991; 100:133–140.
Article
12. Kusnoto B, Evans CA, BeGole EA, de Rijk W. Assessment of 3-dimensional computer-generated cephalometric measurements. Am J Orthod Dentofacial Orthop. 1999; 116:390–399.
Article
13. Mori Y, Miyajima T, Minami K, Sakuda M. An accurate three-dimensional cephalometric system: a solution for the correction of cephalic malpositioning. J Orthod. 2001; 28:143–149.
Article
14. Suh CH. The fundamentals of computer aided X-ray analysis of the spine. J Biomech. 1974; 7:161–169.
Article
15. Selvik G, Alberius P, Fahiman M. Roentgen stereophotogrammetry for analysis of cranial growth. Am J Orthod. 1986; 89:315–325.
Article
16. Baumrind S, Moffitt FH, Curry S. Three-dimensional x-ray stereometry from paired coplanar images: A progress report. Am J Orthod Dentofacial Orthop. 1983; 84:292–312.
Article
17. Baumrind S, Moffitt FH, Curry S. The geometry of three-dimensional measurement from paired coplanar x-ray images. Am J Orthod. 1983; 84:313–322.
Article
18. Cutting C, Bookstein FL, Grayson B, Fellingham L, McCarthy JG. Three-dimensional computer-assisted design of craniofacial surgical procedures: optimization and interaction with cephalometric and CT-based models. Plast Reconstr Surg. 1986; 77:877–887.
19. Selvik G. Roentgen stereophotogrammetric analysis. Acta Radiol. 1990; 31:113–126.
Article
20. Bae GS, Park SB, Son WS. The comparative study of three-dimensional cephalograms to actual models and conventional lateral cephalograma in linear and angular measurements. Korean J Orthod. 1997; 27:129–140.
21. Na ER. Comparison of landmark identification errors between postero-anterior and antero-posterior cephalograms generated from cone-beam CT scan data [PhD dissertation]. Gwangju, Korea: Chonnam National University of Korea;2013.
22. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986; 1:307–310.
Article
23. Bland JM, Altman DG. Measuring agreement in method comparison studies. Stat Methods Med Res. 1999; 8:135–160.
Article
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