Accuracy of measurements of mandibular anatomy in cone beam computed tomography images.
OBJECTIVE
Cone beam computed tomography (CBCT) images of ideally positioned and systematically mispositioned dry skulls were measured using two-dimensional and three-dimensional software measurement techniques. Image measurements were compared with caliper measurements of the skulls.


METHODS
Cone beam computed tomography volumes of 28 skulls in ideal, shifted, and rotated positions were assessed by measuring distances between anatomic points and reference wires by using panoramic reconstructions (two-dimensional) and direct measurements from axial slices (three-dimensional). Differences between caliper measurements on skulls and software measurements in images were assessed with paired t tests and analysis of variance (ANOVA).


RESULTS
Accuracy of measurement was not significantly affected by alterations in skull position or measurement of right or left sides. For easily visualized orthodontic wires, measurement accuracy was expressed by average errors less than 1.2% for two-dimensional measurement techniques and less than 0.6% for three-dimensional measurement techniques. Anatomic measurements were significantly more variable regardless of measurement technique.


CONCLUSIONS
Both two-dimensional and three-dimensional techniques provide acceptably accurate measurement of mandibular anatomy. Cone beam computed tomography measurement was not significantly influenced by variation in skull orientation during image acquisition.
Ludlow
John B
JB
Department of Diagnostic Sciences and General Dentistry, University of North Carolina, Chapel Hill, NC 27599-7450, USA. jbl@email.unc.edu
Laster
William Stewart
WS
See
Meit
M
Bailey
L'Tanya J
LJ
Hershey
H Garland
HG
D000704:Analysis of Variance; D002508:Cephalometry / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008335:Mandibular Condyle / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D015588:Observer Variation; D012886:Skull / Q000000981:diagnostic imaging; D036542:Tomography, Spiral Computed / Q000379:methods*