General Medical Information

Nasal Special Diagnostic Techniques

Shawn D. Newlands

Imaging of the nasal cavity and paranasal sinuses rarely is indicated in the evaluation of uncomplicated rhinitis. However, these studies are indicated to diagnose or evaluate recurrent acute or chronic rhinosinusitis, to examine a patient who has abnormal findings at nasal endoscopy, and to evaluate atypical facial pain. For these purposes, CT is the method of choice. Limited axial CT scans are more informative than are plain sinus radiographs, and the costs of CT is almost the same as that of radiography. Thin-section coronal CT details the anatomic features and is necessary for planning and executing endoscopic sinus surgery for rhinosinusitis.

Rhinomanometry and acoustic rhinometry can be used to document the severity of nasal obstruction. Rhinomanometry is used to measure the resistance to airflow through the nose. This test is useful when an objective measure of the nasal resistance is desired. Such circumstances include documentation of occupational rhinitis with an increase in nasal resistance at work or in testing the efficacy of an intervention for obstruction, such as surgery or medical treatment. In acoustic rhinometry reflection of sound energy is used to map the volume and dimensions of the nasal cavity. At present acoustic rhinometry is of little clinical use.

Serum IgE and serum eosinophil levels often are measured as a screening test for allergy. Neither of these tests has exceptional sensitivity or specificity for allergic rhinitis, so the clinical utility is controversial. Nasal cytologic examination also can be useful in some clinical settings. High nasal eosinophil counts occur among patients with allergic rhinitis and those with nonallergic rhinitis with eosinophilia. High neutrophil counts occur among patients with infectious rhinitis, although some healthy persons have high neutrophil counts. Abnormalities in ciliary motility can be detected by means of examining scrapings of the inferior turbinate.