Cone-beam imaging: applications in ENT.

Cone-beam imaging is an X-ray based volume acquisition method providing 3D images of the head. The reconstructed volume is "isotropic"; spatial resolution varies according to material, equaling or exceeding that of CT but with a much lower radiation intensity. The drawbacks comprise a reduced signal-to-noise ratio and poor density resolution precluding soft-tissue exploration, notably of tumoral processes. This technique is very effective for the study of inflammatory and infectious processes of the head. In dental exploration, its intrinsic qualities enable screening for sinusitis of dental origin with a precision unobtainable on CT. Cone-beam imaging will, in the near future, become the reference examination in sinus assessment. Finally, this technique, at least using the most powerful apparatuses, seems very promising in ear pathology exploration. First applications in chronic otitis, dysplasia, deformity and trauma have been encouraging. Its low sensitivity to metallic artifacts makes it the technique of choice in the follow-up of cochlear implants.