Radiologic imaging is an essential part of the presurgical evaluation of patients with sinusitis and of the monitoring of difficult-to-treat,recurrent, and postsurgical disease. In patients with noninflammatory sinus pathology and those who "baffle" clinical diagnosis, ima-ging is extremely helpful in differentiating the various pathological entities and determining the extent of disease. Computerized tomography (CT), when deemed clinically necessary, is the current modality of choice to evaluate sinusitis. CT's ability to display bone,mucosa, and air makes it a perfect tool for imaging of the paranasal sinuses. The fine bony architecture of the nasal cavity and the para-nasal sinus drainage pathways are depicted accurately with CT examination.