In vivo imaging of the internal nasal valve during different conditions using optical coherence tomography.

OBJECTIVE Previously, we proposed long-range optical coherence tomography (LR-OCT) to be an effective method for the quantitative evaluation of the nasal valve geometry. Here, the objective was to quantify the reduction in the internal nasal valve angle and cross-sectional area that results in subjective nasal airway obstruction and to evaluate the dynamic behavior of the valve during respiration using LR-OCT. METHODS For 16 healthy individuals, LR-OCT was performed in each naris during: 1) normal respiration, 2) peak forced inspiration, 3) lateral nasal wall depression (to the onset of obstructive symptoms), and 4) after application of a topical decongestant. The angle and the cross-sectional area of the valve were measured. RESULTS A reduction of the valve angle from 18.3° to 14.1° (11° in Caucasians and 17° in Asians) and a decrease of the cross-sectional area from 0.65 cm2 to 0.55 cm2 led to subjective nasal obstruction. Forceful breathing did not significantly change the internal nasal valve area in healthy individuals. Application of nasal decongestant resulted in increased values. CONCLUSION LR-OCT proved to be a fast and readily performed method for the evaluation of the dynamic behavior of the nasal valve. The values of the angle and the cross-sectional area of the valve were reproducible, and changes in size could be accurately delineated. LEVEL OF EVIDENCE 2b. Laryngoscope, 128:E105-E110, 2018.