Dynamic Light Scattering for In Vivo Hemorheology
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Solution Overview
Problem
Current optical methods for in vivo measurement of hemorheological parameters suffer from limited sensitivity and are prone to motion artifacts, particularly when blood flow is high or low, and cannot distinguish between blood-originated and tissue-related signals effectively.
Innovation Solution
The use of dynamic light scattering (DLS) technique to measure blood-related parameters like viscosity, blood flow, and pressure by analyzing the temporal speckle pattern of scattered light, which differentiates between blood and tissue signals and reduces noise through high-frequency component processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical methods are used to measure hemorheological parameters, then the measurement can be performed non-invasively, but the sensitivity is limited and motion artifacts are prevalent
Solution Approach 1:
The patent replaces conventional optical detection methods with dynamic light scattering (DLS) technology. DLS measures the temporal fluctuations of scattered light intensity caused by Brownian motion of red blood cells, converting optical measurements into precise hemorheological parameter data. This substitution enables accurate measurement of blood viscosity, flow velocity, and other parameters while being insensitive to motion artifacts that plague conventional optical methods.
Solution Approach 2:
The patent changes the measurement parameter from conventional optical absorption/reflection to temporal autocorrelation of scattered light intensity. By analyzing the autocorrelation function of DLS signals at different lag times, the system can extract hemorheological parameters with high precision. The characteristic decay time of the autocorrelation function directly relates to blood viscosity and flow velocity, providing a new parameter space for accurate measurement.
2Loss of information
If time-dependent optical signals are used to track physiological processes, then valuable information about blood dynamics can be obtained, but the measured signal is a convolution of blood and tissue properties making accurate blood parameter determination difficult
Solution Approach 1:
The patent extracts the blood-specific signal component from the mixed optical signal by using DLS autocorrelation analysis. The temporal fluctuations in scattered light intensity are primarily caused by Brownian motion of red blood cells, and the autocorrelation function isolates this blood-related information from tissue background. This extraction enables accurate determination of blood viscosity and flow parameters independent of tissue optical properties.
Solution Approach 2:
The patent introduces the autocorrelation function as an intermediary between the raw optical signal and the blood parameters. By computing the autocorrelation of scattered light intensity over time, the system creates an intermediate representation that highlights blood dynamics characteristics while suppressing tissue-related variations. This intermediary processing step enables accurate blood parameter extraction from complex optical signals.
3Ease of operation
If conventional optical methods are used for blood pressure measurement, then non-invasive measurement is possible, but the accuracy is impaired due to sensitivity to motion artifacts
Solution Approach 1:
The patent replaces conventional optical detection with dynamic light scattering autocorrelation analysis for blood pressure measurement. The system measures temporal fluctuations in scattered light intensity and computes autocorrelation functions to extract hemorheological parameters that correlate with blood pressure. This method maintains non-invasive operation while achieving high accuracy by being insensitive to motion artifacts that affect conventional optical methods.
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
This approach enables accurate measurement of hemorheological parameters and chemical parameters like oxygen saturation and glucose, while minimizing motion artifacts, providing robust and noise-resistant data for blood pressure and flow measurements.
Implementation Method 1
The patent utilizes the effect of dynamic light scattering (DLS) for the in vivo measurement of a subject
Implementation Method 2
These fluctuations are due to the fact that the particles are undergoing Brownian or regular flow motion
Implementation Method 3
a light source unit (e.g. laser) for generating at least partially coherent light
Data Source
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AI summary
A system, method and medical tool are presented for use in non-invasive in vivo determination of at least one desired parameter or condition of a subject having a scattering medium in a target region. The measurement system comprises an illuminating system, a detection system, and a control system. The illumination system comprises at least one light source configured for generating partially or entirely coherent light to be applied to the target region to cause a light response signal from the illuminated region. The detection system comprises at least one light detection unit configured for detecting time-dependent fluctuations of the intensity of the light response and generating data indicative of a dynamic light scattering (DLS) measurement. The control system is configured and operable to receive and analyze the data indicative of the DLS measurement to determine the at least one desired parameter or condition, and generate output data indicative thereof.