Reproducibility of maxillofacial anatomic landmarks on 3-dimensional computed tomographic images determined with the 95% confidence ellipse method.
OBJECTIVE
To assess the plotting reproducibility of landmarks on 3-dimensional computed tomography (3D-CT) images through use of the 95% confidence ellipse in order to propose sufficiently stable coordinate systems for 3D-CT measurements.


METHODS
Six dentists plotted 19 landmarks twice on 3D-CT images. Scatterplots and the 95% ellipses were produced 3-dimensionally, and the areas of the ellipses were calculated for evaluating the reproducibility of landmarks.


RESULTS
The plotting reproducibility of each landmark showed characteristic features. Among five landmarks (the sella [S], nasion [N], basion [Ba], orbitale [Or], and true porion [Po]) that are frequently used as reference points on cephalograms, Ba showed the smallest areas for all three coordinate axes, indicating high reproducibility. The coronoid process (CP) and the tooth-related landmarks showed relatively high reproducibility.


CONCLUSIONS
Sufficiently stable coordinate axes could be proposed for different treatments and studies.
Muramatsu
Atsushi
A
Department of Orthodontics, Aichi-Gakuin University School of Dentistry, Nagoya, Japan.
Nawa
Hiroyuki
H
Kimura
Momoko
M
Yoshida
Kazuhito
K
Maeda
Masahito
M
Katsumata
Akitoshi
A
Ariji
Eiichiro
E
Goto
Shigemi
S
D002508:Cephalometry / Q000379:methods* / Q000706:statistics & numerical data; D004424:Ear Canal / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005147:Facial Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008963:Molar / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009295:Nasal Bone / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009915:Orbit / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012658:Sella Turcica / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D012886:Skull / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D019291:Skull Base / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*