Morphologic examination of the temporal bone by cone beam computed tomography: comparison with multislice helical computed tomography.
BACKGROUND
High-resolution CT imaging is essential to diagnosis and follow-up of temporal bone pathology. Morphologically, CT is the reference examination. The requirement of long-term follow-up thus exposes patients to cumulative radiation doses. Limiting exposure to ionizing radiation is an increasing concern of public health authorities. The principal advantage of Cone Beam CT (CBCT) lies in a significant reduction in radiation dose. The main objective of the present study was to assess the morphologic concordance between CBCT and Multislice Helical Computed Tomography (MSCT) on 20 anatomic landmarks corresponding to regions of interest in clinical practice. The secondary objectives were to compare the two techniques qualitatively in stapes and footplate assessment and measurement of footplate thickness, and quantitatively in terms of dosimetry.


METHODS
An experimental anatomical study was performed on 12 temporal bones from fresh human cadavers of unknown clinical history. Each underwent CBCT and MSCT.


RESULTS
There was no significant difference in morphologic assessment of the temporal bones on the two techniques. Exploration of the stapes, incudostapedial joint, anterior stapediovestibular joint and footplate was qualitatively more precise on CBCT, and footplate thickness showed less overestimation than on MSCT. CBCT delivered 22 times less radiation than MSCT under the present experimental conditions.


CONCLUSIONS
CBCT provides reliable morphologic assessment of temporal bone, thanks to higher spatial resolution than on MSCT, with significantly reduced radiation dose.
Service d'ORL, hôpital Purpan, CHU de Toulouse, place du Dr-Baylac, 31059 Toulouse cedex 9, France.
M
M
Dahmani-Causse
M
M
Marx
O
O
Deguine
B
B
Fraysse
B
B
Lepage
B
B
Escudé
D002102:Cadaver; D054893:Cone-Beam Computed Tomography; D004429:Ear Ossicles / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D061330:Multidetector Computed Tomography; D011829:Radiation Dosage; D013701:Temporal Bone / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed