Sensing the full vibrational patterns of the tympanic membrane could serve as a direct diagnostic tool for outer and middle ear pathologies, and could assist various surgical intervention procedures that depend on detailed inspection of the tympanic membrane. Three-dimensional imaging of acoustic vibrations in an excised tympanic membrane was demonstrated using optical coherence tomography, while stroboscopic holography was used for ex vivo measurement of the motion at discrete phase delays of a surgically exposed tympanic membrane within a fresh temporal bone. Using interferometric Fourier-domain imaging of a single spectrally encoded transverse line, combined with slow single-axis scanning for capturing a two-dimensional field of view, we have previously demonstrated high-resolution imaging of both amplitude and phase of a vibrating surface. In this work, we design our interferometric spectrally encoded imaging system for incorporation into a commercially available digital otoscope. The system uses a new compact design that was integrated into the optical path of the otoscope, where the acoustic waveform was generated in a simple earbud and coupled to the ear canal through the insufflation port of the device. Using data processing with variable spectral windowing, we demonstrate vibrational imaging of a membrane inside an outer ear model with approximately 4.5-mm-diameter field of view and up to 0.6 nm axial resolution. Future in vivo experiments with human volunteers will allow the study and development of the system for clinical diagnostics applications.
|