A comparison between computerized tomography, magnetic resonance imaging, and laser scanning for capturing 3-dimensional data from an object of standard form.
OBJECTIVE
The study's aim was to compare dimensional measurements on computer images generated from data captured digitally by 3 different methods of the surfaces of a plastic cube of known form to those obtained directly from the cube itself.


METHODS
Three-dimensional images were reconstructed of a plastic cube obtained by computerized tomography (CT), magnetic resonance imaging (MRI), and laser scanning. Digital calipers were used to record dimensional measurements between the opposing faces of the plastic cube. Similar dimensional measurements were recorded between the cube faces on each of the reconstructed images. The data were analyzed using a 2-way ANOVA to determine whether there were differences between dimensional measurements on the computer images generated from the digitization of the cube surfaces by the different techniques, and the direct measurement of the cube itself.


RESULTS
A significant effect of how the measurements were taken (ie, direct, CT, MRI, and laser scanning) on the overall variation of dimensional measurement (P < .0005) was observed. Post hoc tests (Bonferroni) revealed that these differences were due principally to differences between the laser-scanned images compared to other sources (ie, direct, CT, and MRI). The magnitude of these differences was very small, up to a maximum mean difference of 0.71 mm (Cl +/- 0.037 mm).


CONCLUSIONS
All 3 methods of imaging would be of value in further studies, not only for the fabrication of complex shapes such as prosthetic ears, but also for other facial prostheses.
Coward
Trevor J
TJ
Department of Fixed and Removable Prosthodontics, Guy's, King's and St. Thomas' Dental Institute, Denmark Hill Campus, Caldecut Road, London, SE5 9RW, England. Trevor.coward@kcl.ac.uk
Scott
Brendan J J
BJ
Watson
Roger M
RM
Richards
Robin
R
D000703:Analog-Digital Conversion; D000704:Analysis of Variance; D004431:Ear, External / Q000033:anatomy & histology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007834:Lasers; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed