Development of a hand-held OCT laryngoscope for reconstruction of 4-D vocal fold dynamics

Cross-sectional 4-D imaging of vocal fold morphology and function is desirable for accurate diagnosis of many vocal fold pathologies, which occur throughout the epithelial layer and alter the mucosal wave. Clinical videoendoscopy provides qualitative diagnostic information but remains limited to surface visualization of layered vocal fold structure and two-dimensional mucosal vibration. While OCT has been investigated to address the shortcomings of standard 2-D endoscopy, challenges remain in reconstruction of the 4-D mucosal wave over the entire vocal fold structure. To address these challenges, we have developed a fast-scanning OCT laryngoscope to enable asynchronous Nyquist sampling of the human voice fundamental frequency range (and its harmonics, up to 1 kHz). We present a new algorithm for reconstruction of the 4-D vocal fold dynamics during phonation using OCT volume data of the entire anterior-posterior vocal fold structure. Reconstruction of the vibration of a vocal fold phantom confirmed feasibility of the algorithm and preliminary reconstruction of the in vivo vocal fold glottal cycle is presented. This work represents the first cross-sectional Nyquist sampling of the in vivo human mucosal wave using an OCT system with hardware capable of encompassing the human fundamental frequency range (i.e., 90-260 Hz). The developed OCT laryngoscope and algorithm will enable volumetric representations of vocal fold dynamics in the clinic and development of quantitative metrics for diagnostic and interventional guidance.