To investigate olfactory bulb volume and olfactory sulcus depth in patients with Behçet's disease, using magnetic resonance imaging.

Cranial magnetic resonance imaging scans of 27 adults with Behçet's disease (10 males and 17 females) and 27 healthy controls were examined. Olfactory bulb volume and olfactory sulcus depth were measured on coronal, T2-weighted, spectral pre-saturation with inversion recovery sequences.

Bilateral olfactory bulb volume and right-sided olfactory sulcus depth were significantly lower in the Behçet's disease group than in the control group (p < 0.05). Left-sided olfactory sulcus depth increased with Behçet's disease duration. In both groups, olfactory bulb volume was significantly higher in the left than the right side. There were no gender differences for olfactory bulb volume and olfactory sulcus depth. Positive correlations were determined between right- and left-sided olfactory bulb volume values and between right- and left-sided olfactory sulcus depth values.

Behçet's disease may decrease olfactory functions, related to lower olfactory bulb volume and olfactory sulcus depth. The affected vascular system and possibly damaged neural system, nasal mucosal lesions, and prolonged nasal mucociliary clearance time may cause olfactory dysfunction. Patient follow up is recommended, with magnetic resonance imaging examinations of the olfactory system if necessary.