The upper airway plays a critical role in everyday life due its importance in various physiological functions. Disorders of the upper airway are numerous due to the many different complex tissue structures and special sensory organs that surround the upper airway. The spatial scale needed to study these disorders range from measuring macroscopic anatomical deformities to studying subcellular processes. Collectively, they all have impact on the respiratory function of the airway. Diagnostic imaging plays a crucial role in identification of disease, targeting therapy, and monitoring the response to both surgical and pharmacologic interventions, and both structural and functional imaging can lead to successful planning of individualized treatment therapies.

Optical coherence tomography (OCT) is a noninvasive, high resolution imaging modality that has immense potential as a mesoscopic imaging modality in biological tissue to discern both structure and function. OCT imaging as applied to the upper airway can image tissue structure across the entire micro- and macroscopic scale of anatomic features, and hence has the potential to be a powerful diagnostic tool. My thesis explores the use of a high-speed long-range endoscopic OCT imaging platform to visualize a wide range of upper airway disorders. First, we developed a high speed long-range OCT system to perform in vivo imaging across the entire human upper airway. Endoscopic rotational OCT imaging probes were fabricated and inserted into the airway lumen to generate rapid and anatomically correct volumetric models of the airway. These 3D models were then used in computational fluid dynamics simulations to better identify locations of collapse in obstructive sleep apnea (OSA). Next we utilized our OCT system in the study of subglottic stenosis (SGS). In adults, intraoperative imaging was performed to quantify the improvement in airway cross-sectional area following balloon dilation surgeries. In the neonatal population, imaging was performed in intubated patients to visualize morphological changes in airway tissue structure to positively correlate duration of intubation with SGS progression. Finally, we utilized functional OCT in the form of Doppler OCT to measure the relationship between the beating dynamics of microscopic sub-resolution cilia vs. temperature and drug agents in ex vivo rabbit airway samples.