Hypoplasia of the sphenoid sinuses as a diagnostic tool in cystic fibrosis

Purpose: To measure and compare the size of the sphenoid sinuses in patients with cystic fibrosis (CF) to patients with inflammatory sinonasal disease, and to correlate the size with number of CF mutations in each patient. Material and Methods: Ninety-six CF patients aged 5-47 years (median 19 years) and 130 control patients aged 7-51 years (median 32 years) were examined using coronal CT of the paranasal sinuses. In each patient, the CT image with the largest coronal area of the sphenoid sinuses was scanned into a Macintosh computer with image processing and analysis software. Largest coronal area and largest circumference of the right and left sphenoid sinuses were automatically measured. Additionally, antero-posterior extension of the sphenoid sinuses was calculated from the lateral scanograms. CF patients were grouped according to number of confirmed mutations (CF-0, CF-1, or CF-2). Results: CF patients generally had small sphenoid sinuses. The largest difference for all parameters were observed between the CF-2 and the control groups (p<0.0001). No CF-2 patient had pneumatization beyond the presphenoid. The CF-0 and CF-1 groups consisted of two populations, one overlapping the CF-2 group and another overlapping the control group. Conclusion: Hypoplasia of the sphenoid sinuses is a characteristic finding in CF patients. When pneumatization of the basisphenoid is present, the existing CF diagnosis should be questioned. (orig.)