In vivo cross-sectional imaging of the phonating larynx using long-range Doppler optical coherence tomography

Carolyn A. Coughlan, Li-dek Chou, Joseph C. Jing, Jason J. Chen, Swathi Rangarajan, Theodore H. Chang, Giriraj K. Sharma, Kyoungrai Cho, Donghoon Lee, Julie A. Goddard, Zhongping Chen, Brian J. F. Wong
2016 Scientific Reports  
Diagnosis and treatment of vocal fold lesions has been a long-evolving science for the otolaryngologist. Contemporary practice requires biopsy of a glottal lesion in the operating room under general anesthesia for diagnosis. Current in-office technology is limited to visualizing the surface of the vocal folds with fiber-optic or rigid endoscopy and using stroboscopic or high-speed video to infer information about submucosal processes. Previous efforts using optical coherence tomography (OCT)
more » ... e been limited by small working distances and imaging ranges. Here we report the first full field, high-speed, and long-range OCT images of awake patients' vocal folds as well as cross-sectional video and Doppler analysis of their vocal fold motions during phonation. These vertical-cavity surface-emitting laser source (VCSEL) OCT images offer depth resolved, high-resolution, high-speed, and panoramic images of both the true and false vocal folds. This technology has the potential to revolutionize in-office imaging of the larynx. The vocal fold is a complex viscoelastic structure with multiple distinct tissue layers, which differ in both their optical and mechanical properties. In vivo imaging has largely been relegated to evaluation of surface morphology using classic mirror examination or conventional fiber-optic and rigid endoscopy. Functional imaging of vocal fold mechanics can be accomplished using stroboscopic methods or high-speed digital imaging, and both facilitate analysis of the vocal fold mucosal wave propagation during phonation. Regardless, all clinically used technology to date images only the surface, and hence can only provide clues with respect to the underlying sub-epithelial tissue structure. Determining the cross-sectional microanatomy in vivo, particularly during phonation, will lead to a better understanding of vocal fold mechanics and provides a means to more reliably diagnose vocal fold pathology without biopsy. The vocal fold is a functional layered structure with spatially varying mechanical properties that vibrate with airflow, leading to phonation, a process that produces multiple harmonics and generates normal speech. There is a wide spectrum of disease that can involve the sub-epithelial region of the vocal folds. This includes benign (cysts, polyps), premalignant (dysplasia), and malignant lesions. A biopsy under general anesthesia is required to histologically differentiate these lesions. Unfortunately, biopsy of the vocal folds can risk creating permanent damage to the vocal fold and voice quality 1 . In vivo high-resolution imaging of the vocal fold would be of tremendous value for both clinicians and scientists. Optical coherence tomography (OCT) is an imaging modality that acquires high-resolution cross-sectional images of living tissues, and has become the standard for retinal imaging in ophthalmology. It also has emerging applications in cardiology where it has been used to image plaque in the coronary vasculature. In the head, neck, and upper airway, OCT as an investigational technology has focused on imaging early cancers and dysplastic
doi:10.1038/srep22792 pmid:26960250 pmcid:PMC4785353 fatcat:lymeokgusvfuvjpqiod42rfbhe