OBJECTIVE:

The purpose of this study was to use high-speed optical coherence tomography (OCT) to obtain cross-sectional images of the rat cochlea.

STUDY DESIGN AND METHODS:

The cochleae of Sprague- Dawley rats were imaged within 2 to 4 hours after death. Specimens were prepared by removing the bulla to expose the mesotympanum; some images were obtained in intact temporal bones removed from the cranium. The central element of an OCT imaging device is a Michelson interferometer combined with a low-coherence light source. This study used 2 OCT systems with different light sources: 1) a semiconductor optical amplifier operating and 2) a superluminescent diode with peak emissions wavelengths of 1.3 microm and 827 nm, respectively. Images (1.87 x 2.00 mm or 1.87 x 1.00 mm, 10 x 10 microm pixel resolution) were acquired at a frame rate of 1 Hz. Cross-sectional images at 100-microm increments were obtained from a medial-to-lateral direction.

RESULTS:

The scala vestibuli, scala media, scala tympani, modiolus, spiral ligament, and several turns of the cochlea were identified.

CONCLUSION:

These images reflect the ability of OCT to provide images of the internal cochlea structure with micron scale resolution and at near-real time frame rates.