Miniature quantitative optical coherence elastography using a fiber-optic probe with a fabry-perot cavity
Inventors
Assignees
New Jersey Institute of Technology
Publication Number
US-11206986-B2
Publication Date
2021-12-28
Expiration Date
2037-08-11
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Abstract
A miniature quantitative optical coherence elastography system with an integrated Fabry-Perot force sensor for in situ elasticity measurement of biological tissue is provided. The technique has great potential for biomechanics modeling and clinical diagnosis. The qOCE system contains a fiber-optic probe that exerts a compressive force to deform tissue at the tip of the probe. Using the space-division multiplexed optical coherence tomography signal detected by a spectral domain optical coherence tomography engine, probe deformation in proportion to the force applied is quantified, as well as the tissue deformation corresponding to the external stimulus. Simultaneous measurement of force and displacement allows for calculation of Young's modulus from the biological tissue. The provided system has had its effectiveness validated on tissue mimicking phantoms, as well as biological tissues, with the advantages of being minimal invasive and also not requiring the use of external agents or substantial pre-measuring preparation.
Core Innovation
The invention provides a miniature quantitative optical coherence elastography (qOCE) system that incorporates a fiber-optic probe integrated with a Fabry-Perot cavity for in situ elasticity measurement of biological tissues. This qOCE system simultaneously measures the force or stress exerted on the tissue and the resultant tissue deformation or strain. The system utilizes a spectral domain optical coherence tomography (OCT) engine for detection, enabling minimally invasive and real-time mechanical characterization of tissue.
The system uses a fiber-optic probe to exert a compressive force at the tissue site, where the force and tissue deformation are simultaneously measured using space-division multiplexed OCT signals. The Fabry-Perot cavity in the probe quantifies probe deformation proportional to force, while GRIN lenses at the distal end collect backscattered light for tissue imaging and deformation tracking. This enables calculation of Young’s modulus of the tissue, offering quantitative assessment of its mechanical properties.
The problem addressed is that existing methods of optical coherence elastography generally lack the capability for reliable and quantitative force measurement, limiting the ability to compare results across sessions or in longitudinal studies. Conventional OCE measures tissue displacement but typically does not quantify the actual mechanical load applied, resulting in only qualitative characterization. The provided qOCE system overcomes this by simultaneous and quantitative measurement of both force and displacement—enabling direct, repeatable calculation of tissue elasticity in a minimally invasive manner, without need for external agents or dyes.
Claims Coverage
There are two independent claims in the patent, each disclosing a primary inventive feature.
Method for simultaneous quantification of force and deformation in biological tissue using a miniature quantitative optical coherence elastography (qOCE) system
This method utilizes a qOCE system defined miniature by insertion into a 1.8 mm inner diameter tube, comprising: - A fiber-optic probe with an integrated Fabry-Perot (FP) cavity and a pair of GRIN lenses at the distal end. - Inducing compression to deform biological tissue with the probe tip, and generating a common path OCT signal from FP cavity reflections. - Using the common path OCT signal, detected by a spectral domain OCT engine (with spectrometer, SLD, reference arm), to quantify probe deformation proportional to force. - Collecting backscattered light from the compressed tissue via the GRIN lenses for tissue illumination and imaging; the signal interferes with a reference light to yield a Michelson OCT signal for deformation tracking. - Adjusting optical path length of the reference arm to spatially demultiplex the common path and Michelson OCT signals for simultaneous detection with a spectrometer. - Deriving force sensing from the FP cavity and tissue imaging from sample-reference interference. - Measuring force and displacement simultaneously to extract Young's modulus of the biological tissue.
Miniature quantitative optical coherence elastography (qOCE) system with force and displacement measurement capabilities
This system comprises: - A qOCE system configured miniature for a 1.8 mm inner diameter tube, including a fiber-optic probe with an integrated Fabry-Perot cavity and a pair of GRIN lenses. - A probe tip for applying force to induce compression in tissue, with the FP cavity generating a common path OCT signal for probe deformation sensing. - A spectral domain OCT engine (including spectrometer, SLD, and reference arm) for detecting the common path OCT signal and quantifying probe deformation proportional to applied force. - Use of GRIN lenses for collecting backscattered light from the tissue, which is combined with reference light in a Michelson interferometer to generate a Michelson OCT signal for tissue imaging and deformation tracking. - Adjustment of the reference arm optical path length to avoid overlap of signals and allowing simultaneous, spatially demultiplexed detection of both OCT signals. - Force sensing derived from the FP cavity and tissue imaging from the reference/sample interaction, with simultaneous measurement of force and displacement to extract Young’s modulus of the tissue.
The independent claims cover both a method and a system that enable simultaneous and quantitative measurement of force and deformation in biological tissue through a miniature qOCE setup, making possible reliable extraction of tissue elasticity parameters in situ.
Stated Advantages
The system is minimally invasive and does not require external agents or dyes for tissue measurement.
Simultaneous quantification of force and tissue deformation allows calculation of Young's modulus for reliable, quantitative elasticity measurements.
The miniature probe provides access to deep tissue locations for in situ mechanical characterization without the need for tissue biopsy.
High spatial resolution and sensitivity are achieved for elastography compared to ultrasound or MRI-based methods.
The device enables real-time measurements and imaging using OCT signal processing on a graphical processing unit.
No substantial pre-measuring preparation is required for use in clinical and research settings.
Documented Applications
Cancer diagnosis by evaluating mechanical properties of tissue in a minimally invasive manner.
Biomechanics modeling for medical and research purposes by measuring tissue elasticity.
Brain injury study through in situ characterization of mechanical properties of brain tissue.
Tissue engineering applications requiring quantitative assessment of tissue stiffness.
Clinical diagnosis involving quantification of tissue elasticity in vivo without tissue excision.
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