Imaging of Nose and Sinuses

Three principal modalities are used to evaluate the nose and paranasal sinuses: plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Plain x-ray is rarely ever performed for evaluation of sinuses because of poor anatomical delineation and deficiency of soft tissue depiction. Computed tomography has the advantage of providing both good bony and soft tissue details. CT supplies excellent details about the thin bony sinonasal walls and reveals the precise individual anatomy of the nose and paranasal sinuses. It is on the basis of this internal map that endonasal surgery for rhinosinusitis is planned, and therefore inflammatory diseases belong to the domain of CT. The main advantages of MRI is that it more precisely distinguishes tumor signal from adjacent structures and also more precisely demonstrates two critical periosteal linings (periorbital and dura mater), allowing the early detection of perineural spread of disease. Also, as endonasal surgeons are confronted with new challenges, such as endoscopic craniofacial resection, radiologists must be able to provide answers about intracranial neoplastic extension, which is best answered with MR imaging. The best modality currently available to evaluate complex sinonasal pathology is a combination of MRI and CT: the former to better delineate normal from abnormal soft tissues and the latter to show osseous changes.