Imaging the internal structure of the rat cochlea using optical coherence tomography at 0.827 microm and 1.3 microm.
OBJECTIVE
The purpose of this study was to use high-speed optical coherence tomography (OCT) to obtain cross-sectional images of the rat cochlea.


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.


CONCLUSIONS
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.
Wong
Brian J f
BJ
Beckman Laser Institute and Medical Clinic, University of California, Irvine, CA 92612, USA. bjfwong@bli.uci.edu
Zhao
Yonghua
Y
Yamaguchi
Mark
M
Nassif
Nader
N
Chen
Zhongping
Z
De Boer
Johannes F
JF
D019412:Anatomy, Cross-Sectional / Q000295:instrumentation; D000818:Animals; D003051:Cochlea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley; D041623:Tomography, Optical Coherence / Q000379:methods*