Paranasal sinus imaging.

The inability of plain radiographs to yield conclusive information about the ostiomeatal complex in sinusitis is no longer a significant problem. Computed tomography (CT), magnetic resonance imaging (MRI), and improved endoscopic technology now enable almost complete exploration of the sinus anatomy and the pathophysiology of sinus disease. Nasal endoscopy provides a clear view of the anterior nasal cavity--including the middle meatus--in patients with symptoms of sinusitis. However, the maxillary ostia are still difficult to visualize directly. CT is required for noninvasive evaluation of deep ostiomeatal air passages and posterior ethmoid and sphenoid sinuses. MRI of the nasal cavity and paranasal sinuses, although of limited use for displaying nasal morphology, is even more sensitive than CT in identifying fungal concretions and neoplasms.