Frequency and volumetry of infraorbital ethmoid cells (Haller cells) on cone-beam computed tomograms (CBCT) of the mid-face.

Objective: The aim of this study was to determine the frequency and morphology of Haller cells using a new radiological technique that allows examination of the facial skull. Material and methods: In a single center retrospective cohort study the cone-beam computed tomography (CBCT) volume data of the maxillary sinus of 199 patients were analysed (398 paranasal sinuses). If Haller cells were found, their capacity was determined. If orthopantomograms (OPG) were taken in a narrow time frame around the CBCT investigation, the rate of correspondence of the radiological findings was determined. The correlation between frequency of Haller cells and age and gender was calculated. Results: Out of 199 patients 47 showed at least one Haller cell (23.62%). The total number of Haller cells was 64. Correspondence was rare in the same case between the results from different examination procedures with respect to the target object. Conclusions: Bony variants of paranasal sinuses can be analysed using CBCT as an alternative to computed tomography (CT), whereas OPG images do not reliably detect Haller cells.