Purpose

To evaluate endoscopic long-range optical coherence tomography system combined with a pressure sensor to concurrently measure internal nasal valve cross-sectional area and intraluminal pressure.

Methods

A pressure sensor was constructed using an Arduino platform and calibrated using a limiter-controlled vacuum system and industrial absolute pressure gauge. Long-range optical coherence tomography imaging and pressure transduction were performed concurrently in the naris of eight healthy adult subjects during normal respiration and forced inspiration. The internal nasal valve was manually segmented using Mimics software and cross-sectional area was measured. Internal nasal valve cross-sectional area measurements were correlated with pressure recordings.

Results

Mean cross-sectional area during forced inspiration was 6.49 mm². The mean change in pressure between normal respiration and forceful inspiration was 12.27 mmHg. The direct correlation between pressure and cross-sectional area as measured by our proposed system was reproducible among subjects.

Conclusions

Our results demonstrate a direct correlation between internal nasal valve cross-sectional area and nasal airflow during inspiration cycles. Endoscopic long-range optical coherence tomography coupled with a pressure sensor serves as a useful tool to quantify the dynamic behavior of the internal nasal valve.

The human vocal fold (VF) oscillates in multiple vectors and consists of distinct layers with varying viscoelastic properties that contribute to the mucosal wave. Office-based and operative laryngeal endoscopy are limited to diagnostic evaluation of the VF epithelial surface only and are restricted to axial-plane characterization of the horizontal mucosal wave. As such, understanding of the biomechanics of human VF motion remains limited. Optical coherence tomography (OCT) is a micrometer-resolution, high-speed endoscopic imaging modality which acquires cross-sectional images of tissue. Our study aimed to leverage OCT technology and develop quantitative methods for analyzing the anatomy and kinematics of in vivo VF motion in the coronal plane. A custom handheld laryngeal stage was used to capture OCT images with 800 A-lines at 250 Hz. Automated image postprocessing and analytical methods were developed. Novel kinematic analysis of in vivo, long-range OCT imaging of the vibrating VF in awake human subjects is reported. Cross-sectional, coronal-plane panoramic videos of the larynx during phonation are presented with three-dimensional videokymographic and space-time velocity analysis of VF motion. Long-range OCT with automated computational methods allows for cross-sectional dynamic laryngeal imaging and has the potential to broaden our understanding of human VF biomechanics and sound production.