Cone-beam computed tomography: a new method for imaging of the temporal bone.
BACKGROUND
Clinical cone-beam computed tomography (CBCT), used in diagnostics of dental and maxillofacial radiology for almost 10 years, allows three-dimensional (3D) imaging of a focused area, with reasonable radiation dose.


OBJECTIVE
To clarify the applicability of CBCT in imaging of the temporal bone.


METHODS
We imaged cadaver temporal bones, one non-operated and five postmortem operated, with CBCT to evaluate the accuracy of this method in showing clinically important landmarks and the positions of middle-ear implants. In addition, to clarify the imaging protocols for the best possible result, we conducted a contrast-to-noise ratio (CNR) analysis by imaging a specially built phantom insert with different protocols.


RESULTS
For all the temporal bones, image quality was good and of diagnostic value, and the surgical landmarks as well as positions and details of the implants could be accurately observed. Based on measurements conducted with the phantom, the best possible clarity of the images with the machine used (3D Accuitomo; Morita Co., Kyoto, Japan) was achieved with a tube voltage of 80 kVp and a current of 4 mA.


CONCLUSIONS
Cone-beam CT is a promising new method for otologic imaging, based on its accuracy and relatively low radiation exposure per investigation.
Department of Otorhinolaryngology, Helsinki University Central Hospital, Helsinki, Finland. peltla@gmail.com
L I
LI
Peltonen
A A
AA
Aarnisalo
Y
Y
Käser
M K
MK
Kortesniemi
S
S
Robinson
A
A
Suomalainen
J
J
Jero
D002102:Cadaver; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D013701:Temporal Bone / Q000000981:diagnostic imaging*