LAUSR

OBJECTIVE To evaluate the accuracy of three-dimensional (3D) Cone Beam Computed Tomography (CBCT) and Computed Tomography (CT) reconstructions of human temporal bones compared with in situ measurements. MATERIAL AND METHODS Experimental anatomical study of 10 human temporal bones. Wilcoxon's test was used to compare 8 distances on each temporal bone measured in situ and then on 3D CT and CBCT reconstructions. Six landmarks were used: external auditory canal (EAC), tip of the mastoid process, tip of the occiput, zygoma, a point situated 1cm above the tip of the mastoid process (T0) (open technique: lower limit of the mastoidectomy), head of stapes. RESULTS No significant difference was observed between the 3 measuring techniques for any of the distances studied (P>0.05). DISCUSSION This study demonstrates the equivalence of CBCT and CT for temporal bone measurements. CONCLUSION CBCT is a new imaging modality providing 3D reconstructions of the temporal bone that are as reliable as those obtained by CT. As a result of better spatial resolution compared to CT, CBCT is associated with a significantly lower radiation dose. This technique constitutes a morphological progress, as CBCT is comparable to CT, allowing investigation of pathological ears with a lower radiation dose.