Office-based dynamic imaging of vocal cords in awake patients with swept-source optical coherence tomography

Abstract

Optical coherence tomography (OCT) is an evolving noninvasive imaging modality that has been used to image the human larynx during surgical endoscopy. The design of a long gradient index (GRIN) lens-based probe capable of capturing images of the human larynx by use of swept-source OCT during a typical office-based laryngoscopy examination is presented. In vivo OCT imaging of the human larynx is demonstrated with a rate of 40 frames per second. Dynamic vibration of the vocal folds is recorded to provide not only high-resolution cross-sectional tissue structures but also vibration parameters, such as the vibration frequency and magnitude of the vocal cords, which provides important information for clinical diagnosis and treatment, as well as fundamental research of the voice itself. Office-based OCT is a promising imaging modality to study the larynx for physicians in otolaryngology.

Figure 1

Head models: (a) An ex vivo tissue head model made with wooden base plates and springs for simulating dynamic movement; the head is made of Styrofoam, clay, and duct tape, which surrounds the whole surface. This can be used for imaging any sample tissue. (b) A commercially available laryngoscopic manikin, for laryngeal examination practice.

Figure 2

(a) Schematic diagram of a GRIN lens rod–based dynamic focusing swept-source OCT system. (b) Design of the probe. DM—dichroic mirror; Ls are lenses.

Figure 3

(a) Image of the vocal cords while patient is breathing and green aiming beam. (b) Image of the vocal cords while the patient is phonating and green aiming beam.

Figure 4

(a) OCT probe attached to the laryngoscope for office-based laryngoscopic examination. (b) Dual-channel endoscope and OCT signals shown in a monitor.

Figure 5

Vibrating vocal cord with different frequencies: (a) ∼120 Hz and (b) ∼200 Hz. Es are epitheliums, and BMs are basement membranes. The scale bar represents 500 μm.