Systems and methods for measuring tissue oxygenation
Inventors
Darty, Mark Anthony • YUDOVSKY, Dmitry
Assignees
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Publication Number
US-10010278-B2
Publication Date
2018-07-03
Expiration Date
Abstract
The disclosure provides methods and systems for determining tissue oxygenation. An electronic device obtains a data set including a plurality of images of a tissue of interest, each resolved at a different spectral band. Spectral analysis is performed, upon image registration, at a plurality of points in a two-dimensional area of the images of the tissue. The spectral analysis including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point in the plurality of points. The predetermined set of eight to twelve spectral bands includes spectral bands that provide improved methods for measuring tissue oxygenation.
Core Innovation
The invention provides an electronic device that obtains a data set comprising a plurality of images of a tissue of interest, where each respective image is resolved at a different spectral band in a predetermined set of eight to twelve spectral bands and includes an array of pixel values. The device registers the plurality of images on a pixel-by-pixel basis to form a plurality of registered images of the tissue, then performs spectral analysis at a plurality of points in a two-dimensional area of the registered images to determine approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point.
The predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 660±3 nm. The spectral bands with central wavelengths of 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, and 620±3 nm have a full width at half maximum of less than 15 nm, and the spectral band with the central wavelength of 660±3 nm has a full width at half maximum of less than 20 nm.
The invention further encompasses a nontransitory computer-readable storage medium storing one or more programs that, when executed by an electronic device with a processor and memory, cause the device to obtain the plurality of tissue images, register the images pixel-by-pixel, and perform two-dimensional spectral analysis at a plurality of points. In the disclosed implementations, dependent claim features include correcting absorption signals for melanin contribution and signal loss from diffuse scattering losses to produce corrected absorption signals prior to determining approximate oxyhemoglobin and deoxyhemoglobin levels.
Claims Coverage
The partial content identifies two independent claims: an electronic-device claim and a computer-readable-storage-medium claim. Both independent claims cover the same core workflow—multi-band tissue imaging, pixel-by-pixel registration, and two-dimensional spectral analysis to estimate oxyhemoglobin and deoxyhemoglobin—together with specified central wavelength and bandwidth constraints for the spectral bands.
Pixel-by-pixel registration of multi-band tissue images
Obtaining a data set comprising a plurality of images of a tissue of interest resolved at a different spectral band in a predetermined set of eight to twelve spectral bands, each image comprising an array of pixel values, and registering the plurality of images on a pixel-by-pixel basis to form a plurality of registered images of the tissue.
Two-dimensional spectral analysis for approximate hemoglobin levels
Performing spectral analysis at a plurality of points in a two-dimensional area of the plurality of registered images, including determining approximate values of oxyhemoglobin levels and deoxyhemoglobin levels at each respective point.
Predetermined spectral bands with specified central wavelengths and bandwidths
The predetermined set of eight to twelve spectral bands includes spectral bands having central wavelengths of 520±3 nm, 540±3 nm, 560±3 nm, 580±3 nm, 590±3 nm, 610±3 nm, 620±3 nm, and 660±3 nm, with full width at half maximum of less than 15 nm for 520±3 nm through 620±3 nm and less than 20 nm for 660±3 nm.
Across both independent claims, the inventive coverage centers on pixel-by-pixel registration of tissue images acquired across a predetermined set of eight to twelve spectral bands, two-dimensional spectral analysis at multiple points to determine approximate oxyhemoglobin and deoxyhemoglobin levels, and specified central wavelengths and full width at half maximum constraints for the spectral bands.
Stated Advantages
Reduced computational burden using fewer wavelengths.
Documented Applications
Hyperspectral/multispectral tissue oxygenation imaging and assessment using an imaging device and spectral analysis to support clinical ulcer-healing prediction performance in a clinical simulation context tied to peripheral arterial disease (PAD) or critical limb ischemia.
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