Phase-Sensitive OCT Tissue Stiffness via Intrinsic Pulsations
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Solution Overview
Problem
Current methods for assessing tissue biomechanical properties, such as ultrasound elastography and magnetic resonance elastography, rely on external excitation, which limits evaluation due to factors like excitation bandwidth and patient comfort, and are not suitable for rapid, high-resolution, non-invasive measurements of ocular tissues like the cornea.
Innovation Solution
The use of optical coherence elastography (OCE) that employs phase-sensitive optical coherence tomography to measure intrinsic displacements caused by pulsatile motion from the cardiovascular system, allowing for non-invasive and highly sensitive assessment of tissue mechanical properties without external excitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external excitation is used in ultrasound elastography and magnetic resonance elastography to assess tissue biomechanical properties, then tissue deformation can be detected to determine elasticity, but the evaluation is limited by excitation bandwidth, tissue response, and patient comfort
Solution Approach 1:
The system utilizes the tissue's own physiological pulsations (intrinsic excitations from cardiovascular system) as the excitation source, eliminating the need for external excitation devices. The tissue naturally responds to its own physiological movements, allowing elastography measurements without external mechanical excitation, thereby improving patient comfort and evaluation flexibility while maintaining measurement precision
Solution Approach 2:
The patent replaces external mechanical excitation systems (ultrasound transducers, magnetic resonance gradient coils) with detection of intrinsic physiological mechanical movements. The optical coherence tomography system detects tissue displacement caused by natural pulsations, substituting the mechanical excitation approach with an optical detection approach that measures the consequences of intrinsic mechanical activity
2Measurement precision
If external excitation is applied to measure tissue mechanical properties, then deformation data can be obtained, but patient comfort is reduced and acquisition time increases
Solution Approach 1:
The system captures tissue responses to ongoing physiological pulsations in real-time, using the tissue's natural rhythmic movements as the excitation source. This eliminates the need for repeated external excitation cycles, allowing stiffness measurement during normal physiological function without extending acquisition time or reducing patient comfort
Solution Approach 2:
The system leverages the periodic nature of physiological pulsations (heartbeat-driven) as the excitation source. By synchronizing measurements with these natural periodic movements, the system obtains sufficient deformation data for stiffness calculation without requiring additional excitation cycles, thereby maintaining measurement precision while reducing total acquisition time
3Measurement precision
If conventional elastography methods are used, then tissue elasticity can be assessed, but spatial imaging resolution and acquisition speed are insufficient for ocular tissues
Solution Approach 1:
The patent replaces ultrasound or magnetic resonance-based elastography with optical coherence elastography using phase-sensitive optical coherence tomography. This substitution provides superior spatial resolution for ocular tissues while maintaining elasticity measurement capability, as optical methods inherently offer higher resolution for superficial tissues like the cornea compared to acoustic or magnetic methods
Solution Approach 2:
The system uses intrinsic pulsations as the excitation source, allowing rapid sequential imaging during natural tissue movement. This eliminates the need for slow, repeated external excitation cycles required by conventional methods, achieving both high spatial resolution and fast acquisition speed suitable for delicate ocular tissues
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
OCE provides superior spatial imaging resolution and faster acquisition speed, enabling the detection of early stages of ocular diseases like keratoconus and evaluation of therapeutic procedures with improved sensitivity and patient comfort.
Implementation Method 1
The pulsatile motion within the body, e.g., from the heartbeat, creates small displacements, which are detected by a system.
Implementation Method 2
using phase sensitive and sufficiently high speed interferometry
Data Source
AI summary
A system and method for measuring biomechanical properties of tissues without external excitation are capable of measuring and quantifying these parameters of tissues in situ and in vivo. The system and method preferably utilize a phase-sensitive optical coherence tomography (OCT) system for measuring the displacement caused by the intrinsic heartbeat. The method allows noninvasive and nondestructive quantification of tissue mechanical properties. Preferably, the method is used to detect tissue stiffness and to evaluate its stiffness due to intrinsic pulsatile motion from the heartbeat. This noninvasive method can evaluate the biomechanical properties of the tissues in vivo for detecting the onset and progression of degenerative or other diseases and evaluating the efficacy of therapies.