CT of anatomic variants of the paranasal sinuses and nasal cavity: Poor correlation with radiologically significant rhinosinusitis but importance in surgical planning

OBJECTIVE. The purpose of this study was to determine the incidence of sinonasal anatomic variants and to assess their relation to sinonasal mucosal disease. MATERIALS AND METHODS. A retrospective evaluation of 192 sinus CT examinations of patients with a clinical history of rhinosinusitis was conducted. The CT scans were evaluated for the presence of several anatomic variants of the sinonasal cavities, and the prevalence of each variant was calculated. Prevalences of all sinonasal anatomic variants were compared between patients who had minimal to no apparent imaging evidence of rhinosinusitis and those who had radiologic evidence of clinically significant rhinosinusitis. RESULTS. The most common normal variants were nasal septal deviation, Agger nasi cells, and extension of the sphenoid sinuses into the posterior nasal septum. We found no statistically significant difference in the prevalence of any of the studied anatomic variants between patients with minimal and those with clinically significant paranasal sinus or nasal cavity disease. CONCLUSION. Analysis of every routine CT scan of the paranasal sinuses obtained for sinusitis or rhinitis for the presence of different anatomic variants is of questionable value unless surgery is planned.