Single-shot dynamic line-field optical coherence elastography
Dynamic optical coherence elastography (OCE) has been established as a powerful technique capable of mapping tissue biomechanical properties. However, there are still some hurdles before OCE becomes clinically established like ultrasound elastography and magnetic resonance elastography, such as speed. Ultra-fast OCE techniques have been developed utilizing rapid scanning and ultra-fast swept sources, but these techniques are limited in their spatial and temporal resolutions. Here, we present an ultra-fast single-shot line-field OCE (LFOCE) technique based on an ultra-fast spectral domain OCT system. The system was based on a Michelson-type interferometer and a supercontinuum broadband light source. A line-beam focus was generated by a cylindrical mirror. The light was expanded and then split by a beamsplitter into the reference and sample arm paths. The collected interference was then dispersed by a transmission grating and focused onto a high-speed 2D camera. The camera operated at a framerate of 25 kHz with 460 lateral pixels, resulting in an A-scan rate of 11.5 MHz. Validation was performed in gelatin phantoms of various concentrations (8%, 10%, and 12% w/w). A focused air-pulse induced elastic waves in the phantoms, which were captured by the LFOCE system. OCE measurements underestimated the elasticity of the phantoms by ~18.5%. OCE measurements were then performed in in situ rabbit corneas in the whole eye-globe configuration, which were cannulated for artificial intraocular pressure (IOP) control. The elastic wave speeds in the cornea at 10, 15, and 20 mmHg IOP were 3.03±0.05, 4.66±0.03, and 8.85±0.08 m/s, respectively. OCE measurements in an in vivo anesthetized rabbit was able to successfully capture the propagation of the elastic wave, demonstrating the ability of the LFOCE system to perform live measurements.
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University of Houston
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