HEMOGLOBIN MEASUREMENT FROM A SINGLE VESSEL
First Claim
1. A method for measuring total hemoglobin concentration in a blood vessel, comprising:
- illuminating a bodily tissue containing the blood vessel;
generating images of the blood vessel and its surrounding tissue at a first wavelength in the region of an isosbestic wavelength of oxyhemoglobin and deoxy-hemoglobin;
determining at that first wavelength, the comparative imaged intensities of the blood vessel and of the surrounding tissue;
estimating the optical path length of the illumination through the vessel; and
using the estimated optical path length and the comparative imaged intensities of the blood vessel and of the surrounding tissue to determine the total hemoglobin concentration in the blood flowing in the blood vessel.
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Accused Products
Abstract
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.
5 Citations
17 Claims
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1. A method for measuring total hemoglobin concentration in a blood vessel, comprising:
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illuminating a bodily tissue containing the blood vessel; generating images of the blood vessel and its surrounding tissue at a first wavelength in the region of an isosbestic wavelength of oxyhemoglobin and deoxy-hemoglobin; determining at that first wavelength, the comparative imaged intensities of the blood vessel and of the surrounding tissue; estimating the optical path length of the illumination through the vessel; and using the estimated optical path length and the comparative imaged intensities of the blood vessel and of the surrounding tissue to determine the total hemoglobin concentration in the blood flowing in the blood vessel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for measuring total hemoglobin concentration in a blood vessel, comprising:
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a light source configured to illuminate the blood vessel and its surrounding tissue; a camera configured to generate images of the blood vessel and its surrounding tissue at a first wavelength in the region of an isosbestic wavelength of oxyhemoglobin and deoxy-hemoglobin; and a processor configured to; (a) determine from at least one of the images generated at the first wavelength, the comparative imaged intensities of the blood vessel and of the surrounding tissue; (b) estimate the optical path length of the illumination through the blood vessel; and (c) use the estimated optical path length and the comparative imaged intensities of the blood vessel and of the surrounding tissue to determine the total hemoglobin concentration in the blood flowing in the blood vessel. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification