The diagnostic algorithm for sinus diseases continues to evolve along with the advances in imaging modalities. Plain radiographs were once the mainstay of diagnosis of sinus disease and now have been replaced by high-resolution CT for the evaluation of sinus inflammatory diseases. Plain radiographs do not allow adequate evaluation of the ostiomeatal complex or of the sphenoid and ethmoid sinuses because of overlapping anatomic structures. At our institution, plain films are used only in patients in the intensive care units who cannot be transported to the radiology department. CT is the modality of choice for imaging inflammatory disease of the sinuses and the ostiomeatal complex. The detailed anatomy of the ostiomeatal complex as displayed by CT provides a road map for the surgeons prior to endoscopic sinus surgery. Complications of sinus inflammatory disease, in particular intracranial complications, however, are better assessed by MR imaging.

For sinonasal tumors, both CT and MR imaging provide information that is complementary. MR imaging is superior to CT for mapping the extent of tumor because of its obvious advantages, which include multiplanar capability, superior soft tissue contrast, and potential to differentiate neoplasms from adjacent inflammation. CT provides bony detail and anatomic landmarks at the skull base.