UC Irvine

Optical coherence tomography (OCT) is an emerging medical imaging technique that provides tissue cross-sectional images with micrometer resolution in real-time using a nondestructive method. OCT holds great potential in endoscopic applications, such as airway monitoring, since the in-situ monitoring of disease sites using a minimally imaging catheter can facilitate the treatments. One limitation of current endoscopic OCT is the inability to accurately assess the early changes in the tissue microarchitecture and functionality in airway disorders and injuries. In this thesis, I will demonstrate the advancement in the quantitative analysis methods and functional imaging techniques that will lead to the enhanced visualization of early tissue composition and functional changes, thus improving disease prognosis. Towards this objective, two key technological advancements have been made. First, digital quantitative analysis techniques were demonstrated based on two image segmentation algorithms: graph theory and deep learning. Second, we introduced three novel functional imaging techniques to quantify mechanical properties, sub-micron cellular movement, and birefringence in the airway; these were based on i) dynamic airway compliance measurement using a high-speed micromotor OCT probe, ii) spectrally-encoded Doppler measurement using a high-resolution microscopy system, and iii) polarized light illumination and detection using a fiber-based polarization-sensitive OCT. To demonstrate and evaluate the utility of those technological advancements in a clinical setting, we performed ex vivo tissue imaging, postmortem animal imaging, in vivo animal studies of toxic inhaled chemicals, and in vivo imaging of a human upper airway. The findings revealed that automated tissue detection and segmentation combined with functional imaging can significantly improve the understanding of early airway pathophysiology in a disease progression.

Finally, this research work also explored the new application of OCT in gynecology. Although visual inspection and self-reported symptoms are currently used to monitor the progression and treatment of menopausal patients, they lack the objectivity to accurately understand each patient’s conditions. OCT has been proven to provide quantitative tissue information and has been widely adopted in the field of dermatology. With further progress, OCT can be a new powerful tool in the field of pelvic medicine.