Optical Blood Flow Sensing Without Contact or Contrast Agents
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Solution Overview
Problem
Existing methods for measuring blood flow, such as ultrasound and light-based techniques, require direct contact with the subject or use of contrast agents, which can cause side effects and limit the number of measurements.
Innovation Solution
A blood flow measurement device using a light output device and a light receiving sensor, controlled by a processor, measures blood flow without contact by irradiating light at multiple positions and determining intensity differences to calculate flow direction and velocity based on reflected light without contrast agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe is brought into contact with the subject surface for ultrasound measurement, then accurate blood flow information can be measured, but the measurement requires direct contact and specific angle positioning
Solution Approach 1:
The patent replaces the mechanical contact-based ultrasound probe with a non-contact optical measurement system using a light source and light receiving sensor. The light-based system measures blood flow by detecting changes in reflected light intensity caused by moving red blood cells, eliminating the need for skin contact and specific positioning angles while maintaining measurement accuracy
2Measurement precision
If contrast agent is administered for light-based blood flow measurement, then visual determination of blood flow is possible, but side effects occur and the number of measurements is limited
Solution Approach 1:
The patent extracts and eliminates the contrast agent from the measurement system by using intrinsic optical properties of blood (absorption and scattering of light by red blood cells) to detect blood flow. The light receiving sensor detects intensity changes caused by moving red blood cells without requiring any external contrast agents, thereby removing the source of side effects while preserving blood flow visualization capability
Solution Approach 2:
The measurement system utilizes the natural optical characteristics of blood itself (absorption and scattering properties of red blood cells) to perform blood flow measurement. The blood serves its own measurement function without requiring external contrast agents, enabling repeated measurements without side effects
3Loss of information
If fluorescence image method is used for blood flow measurement, then qualitative blood flow information can be obtained, but the method is time-consuming and requires visual checking at specified times
Solution Approach 1:
The patent implements continuous real-time feedback measurement by continuously monitoring reflected light intensity changes at the measurement position. The processor calculates blood flow velocity and direction based on ongoing intensity variations caused by moving red blood cells, providing immediate quantitative feedback without requiring time-consuming visual inspection at specific time points
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
Enables non-invasive, multiple measurements of blood flow with reduced side effects by using light-based methods to determine flow direction and velocity accurately, overcoming limitations of direct contact and contrast agent use.
Implementation Method 1
a light receiving sensor configured to receive the light outputted from the light output device and reflected by a subject
Data Source
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AI summary
A blood flow measurement device according to various embodiments may be configured to irradiate light to a first position of a subject and a second position of the subject located in a first direction with respect to the first position, acquire intensities of the reflected light at the first position and the second position, determine a first value which is a difference between the intensities of the reflected light at the first position and the second position, irradiate light to a third position of the subject located in a second direction with respect to the second position, acquire an intensity of the reflected light at the third position, determine a second value which is a difference between the intensities of the reflected light at the second position and the third position, and determine a blood flow direction based on the first value and the second value.