Olfactory cleft computed tomography analysis and olfaction in chronic rhinosinusitis

BACKGROUND Volumetric analysis of the olfactory cleft by using computed tomography has been associated with olfaction in patients with chronic rhinosinusitis (CRS). However, existing studies have not comprehensively measured olfaction, and it thus remains unknown whether correlations differ across specific dimensions of odor perception. OBJECTIVE To use comprehensive measures of patient-reported and objective olfaction to evaluate the relationship between volumetric olfactory cleft opacification and olfaction. METHODS Olfaction in patients with CRS was evaluated by using "Sniffin' Sticks" tests and a modified version of the Questionnaire of Olfactory Disorders. Olfactory cleft opacification was quantified by using two- and three-dimensional, computerized volumetric analysis. Correlations between olfactory metrics and olfactory cleft opacification were then calculated. RESULTS The overall CRS cohort included 26 patients without nasal polyposis (CRSsNP) (68.4%) and 12 patients with nasal polyposis (CRSwNP) (31.6%). Across the entire cohort, total olfactory cleft opacification was 82.8%, with greater opacification in the CRSwNP subgroup compared with CRSsNP (92.3 versus 78.4%, p < 0.001). The percent total volume opacification correlated with the total Sniffin' Sticks score (r = -0.568, p < 0.001) as well as individual threshold, discrimination, and identification scores (p < 0.001 for all). Within the CRSwNP subgroup, threshold (r = -0.616, p = 0.033) and identification (r = -0.647, p = 0.023) remained highly correlated with total volume opacification. In patients with CRSsNP, the threshold correlated with total volume scores (r = -0.457, p = 0.019), with weaker and nonsignificant correlations for discrimination and identification. Correlations between total volume opacification and the Questionnaire of Olfactory Disorders were qualitatively similar to objective olfactory findings in both CRSwNP (r = -0.566, p = 0.070) and CRSsNP (r = -0.310, p = 0.141) subgroups, although neither reached significance. When examined by two-dimensional planes, the percent opacification of the anterior plane had the strongest correlations with objective olfaction. CONCLUSION Olfactory cleft opacification correlated with objective measures of olfaction in patients with CRS, which correlated with threshold values in patients with CRSsNP and all dimensions of olfaction in those with CRSwNP.