Hemoglobin Measurement from Single Vessel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pulse oximetry is limited to measuring blood oxygenation levels in arterial vessels only, failing to provide accurate information on venous vessels or tissue perfusion, and lacks a simple, non-invasive method for measuring total hemoglobin levels in blood vessels.
Innovation Solution
A system and method using wide-field illumination and narrow-field confocal detection to measure reflection spectra from individual blood vessels, allowing for high-resolution selection and focus on target vessels to determine blood oxygenation and total hemoglobin levels, employing optical fibers for illumination and detection, and processing images at specific wavelengths to estimate optical path length and hemoglobin concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pulse oximetry measures light diffused within tissue to assess arterial blood oxygenation, then arterial oxygenation levels can be measured, but the measurement combines absorption of many blood vessels and cannot separate different blood oxygenation levels of different vessel types
Solution Approach 1:
The patent segments the measurement by using temporal pulsation to separate arterial blood volume changes from constant background attenuation of other vessels, allowing independent measurement of arterial blood oxygenation levels
Solution Approach 2:
The patent exploits the dynamic temporal pulsation of arterial blood volume to distinguish arterial vessels from other vessels, using the time-varying signal to isolate arterial oxygenation information from the static background of other vessels
2Adaptability or versatility
If pulse oximetry relies on temporal pulsation of arterial blood volume to separate different blood oxygenation levels, then arterial vessel measurement is enabled, but venous vessels and other non-pulsed vessels cannot be measured
Solution Approach 1:
The patent inverts the approach by using the constant background signal (previously considered noise to be subtracted) as the measurement target for non-arterial vessels, allowing venous and capillary oxygenation to be measured by analyzing the steady-state light attenuation
3Measurement precision
If conventional methods measure total hemoglobin level by measuring absolute absorption parameter, then hemoglobin concentration can be determined, but the measurement requires complex calibration and is not simple or non-invasive
Solution Approach 1:
The patent uses spectral copying by measuring absorption at multiple wavelengths and comparing against reference spectra to determine total hemoglobin concentration, eliminating the need for absolute calibration while maintaining measurement accuracy
Solution Approach 2:
The patent changes the measurement parameter from absolute absorption to relative spectral absorption ratios at multiple wavelengths, which allows determination of total hemoglobin through spectral analysis without requiring complex calibration procedures
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 accurate measurement of blood oxygenation and total hemoglobin levels in individual blood vessels, providing insights into tissue perfusion and improving diagnostic capabilities for specific tissue conditions.
Implementation Method 1
a light source configured to illuminate a bodily tissue with a plurality of wavelengths
Implementation Method 2
measuring blood oxygenation and hemoglobin by determining reflection spectra from the blood vessel
Implementation Method 3
a detector configured to receive the reflected light and determine a spectrum corresponding to the reflected light
Implementation Method 4
measuring blood oxygenation and hemoglobin by determining reflection spectra from the blood vessel... processing images at specific wavelengths to estimate optical path length and hemoglobin concentration
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A system and method to measure blood oxygenation levels and total hemoglobin on individually selected blood vessels, to provide a representation of the subject condition and of tissue perfusion that may be used for diagnosing specific tissue conditions. Reflection spectra from individual blood vessels or a collection of vessels are measured by using wide-field imaging for selecting target vessels and a narrow-field confocal detection system to enable measuring local blood oxygenation and hemoglobin. Optical fibers may be used to illuminate the target vessel and to detect light diffusively reflected therefrom. The reflection spectra may be analyzed in a spectrometer to extract the ratio of the deoxy- to oxyhemoglobin and to determine their absolute concentration for computing total hemoglobin levels. An alternative implementation uses image processing on camera images of a blood vessel, generated at an isosbestic wavelength of the deoxy- and oxyhemoglobin, and optionally also at neighboring wavelengths.