The accuracy of computed tomography in the diagnosis of chronic rhinosinusitis

Objective: To determine the sensitivity, specificity, and diagnostic accuracy of paranasal sinus computed tomography (CT) in the diagnosis of chronic rhinosinusitis (CRS). Study Design: Prospective dual cohort study. Methods: One hundred seventy-one consecutive patients undergoing endoscopic sinus surgery for CRS were evaluated with CT and staged according to the Lund system. Histopathological findings from sinus specimens were reviewed and graded. A second contemporaneous control group of 130 patients undergoing CT of the sinus regions for other reasons but without a diagnosis of CRS was also staged. Sensitivity, specificity, and the receiver-operator characteristic were determined for the sinus CT in the diagnosis of CRS. Positive and negative predictive values were also computed. Results: In the disease-positive group of patients with CRS, the mean Lund score was 9.8 (95% confidence interval, 9.0-10.6). The mean inflammatory grade on histopathological study was 2.3 (range, 0-4). For the control group (without disease), the mean Lund score was 4.3 (95% confidence interval, 3.5-5.0). The AUC for the receiver-operator characteristic was 0.802 (P <.001). Selecting a Lund score cut-off value of greater than 2 as abnormal, the sinus CT exhibited sensitivity and specificity of 94% and 41%, respectively. Increasing the cut-off value to 4 changed the sensitivity and specificity to 85% and 59%, respectively. Conclusions: The paranasal sinus CT scan exhibits good sensitivity and above-average specificity for the diagnosis of CRS. When added to the history and physical findings, CT may add to the diagnostic accuracy of CRS.