Analysis of intensity variability in multislice and cone beam computed tomography.
OBJECTIVE
The aim of this study was to evaluate the variability of intensity values in cone beam computed tomography (CBCT) imaging compared with multislice computed tomography Hounsfield units (MSCT HU) in order to assess the reliability of density assessments using CBCT images.


METHODS
A quality control phantom was scanned with an MSCT scanner and five CBCT scanners. In one CBCT scanner, the phantom was scanned repeatedly in the same and in different positions. Images were analyzed using registration to a mathematical model. MSCT images were used as a reference.


RESULTS
Density profiles of MSCT showed stable HU values, whereas in CBCT imaging the intensity values were variable over the profile. Repositioning of the phantom resulted in large fluctuations in intensity values.


CONCLUSIONS
The use of intensity values in CBCT images is not reliable, because the values are influenced by device, imaging parameters and positioning.
Oral Imaging Center, Faculty of Medicine, K.U. Leuven, Belgium.
Olivia
O
Nackaerts
Frederik
F
Maes
Hua
H
Yan
Paulo
P
Couto Souza
Ruben
R
Pauwels
Reinhilde
R
Jacobs
D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards*; D021621:Imaging, Three-Dimensional / Q000379:methods; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods / Q000592:standards*