Chronic sphenoid sinusitis revisited: comparison of multidetector axial sections, multiplanar reconstructions, and virtual sinoscopy with endoscopic sinus surgery.

OBJECTIVES To assess the role of multidetector computed tomography (CT) and CT virtual sinoscopy in the evaluation of chronic sphenoid sinusitis and to compare the imaging findings with functional endoscopic sinus surgery. DESIGN Prospective study. SETTING Tertiary care teaching hospital. PATIENTS Thirty patients with chronic sphenoid sinusitis referred for preoperative CT. INTERVENTIONS Thin-section helical axial CT was performed using a multidetector CT scanner with multiplanar reformation (MPR) and volume-rendered or virtual sinoscopy images. Sixty sinuses were divided into quadrants for analysis. Extrasinus extension was labeled as the "fifth quadrant." MAIN OUTCOME MEASURES Imaging findings were compared with those of functional endoscopic sinus surgery, and accuracy of the imaging modality was determined. RESULTS Multidetector CT (axial CT and MPR) was found to be 100% sensitive, specific, and accurate in the evaluation of extent of sinusitis, status of the sinus septum, integrity of the optic nerve canal in relation to the sinus, and type of sinus pneumatization. Axial CT and MPR images showed sensitivity of 98% and specificity of 92% compared with functional endoscopic sinus surgery in evaluating the ostia. Regarding carotid canal integrity, axial CT and MPRs were 100% sensitive and 98% specific. Virtual sinoscopy showed sensitivity and specificity of 67% and 92%, respectively, for the 22 ostia that could be visualized and evaluated using this modality. CONCLUSIONS Axial multidetector CT with secondary MPRs provide the necessary preoperative information regarding extent of disease and sphenoid sinus anatomy. Virtual sinoscopy is a navigational aid, an adjunct to endoscopy, and an educational tool for surgeons-in-training.