Methods, systems and computer program products for determining physiologic status parameters using signals derived from multispectral blood flow and perfusion imaging
Inventors
Chen, Cheng • Ferguson, JR., Thomas Bruce • Kim, Sunghan • Peng, Zhiyong • Jacobs, Kenneth Michael
Assignees
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Publication Number
US-10792492-B2
Publication Date
2020-10-06
Expiration Date
Abstract
Methods for calculating a MetaKG signal are provided. The method including illuminating a region of interest in a sample with a near-infrared (NIR) light source and/or a visible light source; acquiring images of the region of interest; processing the acquired images to obtain metadata associated with the acquired images; and calculating the MetaKG signal from the metadata associated with the acquired images. Related systems and computer program products are also provided.
Core Innovation
The invention calculates a MetaKG signal from metadata associated with multispectral images of a region of interest illuminated with near-infrared and visible light. The signal processing includes average speckle-contrast intensity over time, frequency, time-frequency, and multispectral MetaKG signals. Time-frequency analysis separates cardiac-related and respiratory-related signals, identifies a specific frequency range using power spectral density analysis, and reconstructs the MetaKG signals from that range.
Multispectral signal processing removes motion artifacts and respiratory contamination to improve signal quality by using signals at near-infrared and visible wavelengths to isolate and cancel common motion artifacts. The disclosure also provides residual multispectral MetaKG calculations derived from images at two wavelengths with normalization parameters. The resulting signals enable physiological measurements, including heart-rate mapping, tissue differentiation, perfusion analysis, and cardiovascular measurements.
Claims Coverage
The four independent claims are claims 1, 13, 21, and 30, encompassing four inventive features directed to MetaKG calculation methods, a processor-based system, and a computer program product.
Multispectral MetaKG calculation method
Independent claim 1 covers a method for calculating MetaKG signals from metadata associated with multispectral images, comprising average-intensity, frequency, time-frequency, and multispectral signal processing. The time-frequency processing separates cardiac-related and respiratory-related signals and reconstructs each MetaKG signal using a frequency range determined through power spectral density analysis.
Processor-based MetaKG calculation system
Independent claim 13 covers a computer system comprising a processor and memory with program code to obtain metadata associated with multispectral images and calculate MetaKG signals. The processing supports average-intensity, frequency, time-frequency, and multispectral calculations, including cardiac-related and respiratory-related signal separation and reconstruction based on a determined frequency range.
Computer program product for MetaKG calculation
Independent claim 21 covers a computer program product containing computer-readable program code for calculating MetaKG signals from multispectral image metadata. The code executes processing that provides average-intensity, frequency, time-frequency, and multispectral signals, separating cardiac-related and respiratory-related signals and reconstructing each MetaKG from a determined frequency range.
Residual multispectral MetaKG calculation
Independent claim 30 covers calculating a residual multispectral MetaKG signal from images at two wavelengths using normalization parameters. The claim also provides multispectral signal processing that includes average-intensity, frequency, and time-frequency MetaKG calculations to remove motion artifacts and improve signal quality.
The independent claims cover MetaKG calculation across a method, a computer system, and a computer program product, as well as a method specifying residual multispectral MetaKG calculation. Across all elements of the claim, the central features focus on multispectral image metadata processing, time-frequency separation of cardiac and respiratory signals, and signal reconstruction.
Stated Advantages
Multispectral signal processing removes motion artifacts and improves signal quality.
Documented Applications
Determining physiological status parameters, including heart rate, heart-rate variability, R-to-R interval measures, blood-pressure thresholds, rate-pressure product, perfusion measures, and a contractility index.
Determining tissue oxygen content, hemoglobin content, or temperature from calculated MetaKG signals.
Differentiating abnormal tissue from normal tissue and indicating a degree of abnormality associated with an underlying physiological response using frequency components of average intensity over time.
Generating a two-dimensional heart-rate map within a field of view and changing the region-of-interest configuration.
Acquiring blood-flow and perfusion data, including instantaneous perfusion, relative perfusion values at a pixel and a single point in time, perfusion-curve measures, and relating MetaKG values to physiological status parameter thresholds.
Separating cardiac-related and respiratory-related signals to provide cardiac MetaKG and respiratory MetaKG signals.
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