Quantitative optical coherence elastography based on fiber-optic probe for in situ measurement of tissue mechanical properties

Abstract

Abstract:We developed a miniature quantitative optical coherence elastography (qOCE) instrument with an integrated Fabry-Perot force sensor, for in situ elasticity measurement of biological tissue. The technique has great potential for biomechanics modeling and clinical diagnosis. We designed the fiber-optic qOCE probe that was used to exert a compressive force to deform tissue at the tip of the probe. Using the space-division multiplexed optical coherence tomography (OCT) signal detected by a spectral domain OCT engine, we were able to quantify the probe deformation that was proportional to the force applied, and to quantify the tissue deformation corresponding to the external stimulus. Simultaneous measurement of force and displacement allowed us to extract Young's modulus of biological tissue. We experimentally calibrated our qOCE instrument, and validated its effectiveness on tissue mimicking phantoms and biological tissues.

Nonlinear characterization of elasticity using quantitative optical coherence elastography

“…In our previous work, we demonstrated a miniature quantitative OCE (qOCE) instrument which simultaneously measured the force exerted to tissue and the resultant tissue deformation [19]. We also demonstrated that our qOCE technique was able to provide depth resolved stiffness assessment in a muti-layer structure [20].…”

“…1(a)) utilizes a spectral domain OCT (SD OCT) engine operated at 1300nm. A detailed description of the system can be found in our previous publication [19,21]. Briefly, the system has a 91 kHz Ascan rate and a ~7.5μm axial resolution.…”

“…A miniature fiber optic qOCE probe integrated with a Fabry-Perot (FP) interferometer is used to indent the tissue sample and collect optical signal for elasticity assessment [19]. The probe has a lead-in single mode fiber connected to its proximal end and a pair of GRIN lenses (1.8mm diameter) attached to its distal end.…”

“…The fundamental data acquisition frequency for stress and strain signal was 10 kHz, determined by an external trigger source. As described in our recent publication, we have calibrated our qOCE instrument and demonstrated force and displacement measurement with high linearity and accuracy [19]. We have developed high-speed software based on GPU to quantify stress and strain for our quantitative study of linear and nonlinear elasticity of tissue, as shown in Fig.…”

Multimodal probe for optical coherence tomography epidetection and micron-scale indentation

“…Recent OCE works obtained micro-scale resolution [21][22][23][24] elastograms, improving the OCT signal processing to extract more accurate strain measurements and reducing the contact area to apply a more localized mechanical stimulus; e®ort in miniaturization resulted in the needle-based OCE for in vivo and in situ characterization. [25][26][27] Over the last few years, our group has pioneered a new indentation technique that has been tailored for applications in life science research. [28][29][30] The technique relies on a ferrule-top probe, which is obtained by assembling a millimeter-size cantilever, equipped with a % 100 m diameter sphere on its free hanging end on a small glass block.…”