The role of acoustic rhinometry in studying the nasal cycle.

The nasal cycle has been demonstrated in man using several techniques, including magnetic resonance imaging, anterior rhinoscopy, rhinomanometry, all of which have limitations due to expense, discomfort, limited scope or poor reproducibility. Acoustic rhinometry is a new technique which analyses nasal geometry throughout the nasal cavity, not just at the flow-limiting segment. Six adult volunteers were examined at 15-to 30-min intervals using acoustic rhinometry. The classical alternating cycle was seen in three subjects, a non-classical cycle was seen in two, and no cycle seen in one subject. Changes occurred throughout the nasal cavity and corresponded with fluctuations in subjective scores of obstruction and, in one case, with nasal resistance measurements. Acoustic rhinometry is a rapid, reproducible and non-invasive technique. This pilot study demonstrates that it has potential for studying in detail the physiology of the nasal cycle.