Clinical implication of the olfactory cleft in patients with chronic rhinosinusitis and olfactory loss.

OBJECTIVE To evaluate the relationship between findings via osteomeatal unit computed tomography (OMU CT) of the olfactory cleft and olfactory function in patients with chronic rhinosinusitis (CRS). DESIGN Retrospective review of medical records. SETTING Referral center. PARTICIPANTS Two hundred ten patients with CRS who underwent OMU CT and olfactory function tests were included in this study. MAIN OUTCOME MEASURES All the paranasal sinuses were graded via the Lund-Mackay scoring system. The olfactory cleft was graded on a scale of 0 to 4 according to its opacification. Olfactory function was evaluated by the butanol threshold test (BTT) and the 16-odor identification test (OIT). RESULTS The radiologic grade of the olfactory cleft was more significantly correlated with olfactory function than the grades of the paranasal sinuses. In patients without allergy, the BTT and OIT scores were inversely correlated with the CT score of the olfactory cleft. However, in patients with allergy, only the BTT score had a negative correlation with the CT score of the olfactory cleft, whereas the OIT score did not. The OIT score showed a significant negative correlation with the opacification of the olfactory cleft in the mild and moderate CRS group only, whereas the BTT score showed a significant negative correlation in all stages of CRS. CONCLUSIONS The opacification of the olfactory cleft had a negative correlation with the olfactory function scores in patients with CRS. The olfactory cleft findings on OMU CT may give some clues to the olfactory function in patients with CRS.