Limited Coronal CT: An Alternative Screening Examination for Sinonasal Inflammatory Disease

Coronal CT is the definitive procedure for radiologic evaluation of sinonasal inflammatory disease, yet many clinicians rely on the less expensive plain film sinus series. We designed a limited four slice coronal CT and prospectively compared it with conventional coronal CT and plain film sinus series in 25 patients to determine whether a limited CT examination is a suitable alternative to these other radiologic procedures in screening for sinonasal inflammatory disease. The presence, amount, and location of mucous membrane disease, opacification, air fluid levels, retention cysts, erosions, and anomalies were recorded for each technique. The limited CT agreed with the complete CT in 82% of the 200 sinus compartments reviewed. Localized disease, usually mucosal thickening of 3 mm or less and missed on the limited CT, but detected on the complete CT, accounted for 22 of 36 errors of interpretation. Underestimation of mucosal disease, usually 2 mm or less, accounted for eight errors and misinterpretation of partial volume effect for three errors. Using complete CT as the established standard, plain film missed 37 instances of disease detected on the limited CT; 73% involved an error of mucosal thickening 4 mm or greater. A limited coronal CT of the paranasal sinuses offers a potentially lower cost alternative to complete CT in screening for sinonasal inflammatory disease. It is more accurate than plain film series. Localized disease and osteomeatal disease is underestimated with the current protocol, and so a limited CT should not be used for evaluating potential cancer patients or for surgical planning.