The nasal valve: new insights on the static and dynamic NV with MR-imaging.

Purpose: We assessed the static nasal valve angle with MR imaging in healthy subjects and evaluated the complex mechanism of nasal valve dynamics during physiologic and forced inspiration.
Methods: In 17 healthy subjects, measurements of the static nasal valve angle were conducted on MR scans, using a TSE Axial T2-weighted sequence and a 3 mm slice thickness. The dynamic changes of nasal valve movement were detected using MR Cine-imaging techniques.
Results: The static median angle of the nasal valve was found to be 28.6° with a range of 12.7°-39.3°. The median degree of nasal valve collapse during forced inspiration was 68% (range 20-99%) of the baseline (static nasal valve angle). In the moderately forced inspiration (3 s) the median nasal valve angle declined to 76% of the baseline angle (range 42-100%). In the physiologic or unforced inspiration, the median nasal valve angle was reduced to 86.3% of the baseline angle (range 52-100%).
Conclusion: MRI, as a non-invasive tool, is a reliable method for evaluation of the static nasal valve angle and for the illustration of the complex nasal valve dynamics.