Methods, systems and computer program products for determining physiologic status parameters using signals derived from multispectral blood flow and perfusion imaging
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.
1. A method for calculating a MetaKG signal, the method comprising:
illuminating a region of interest in a sample with at least one multi-wavelength light source, wherein the multi-wavelength light source is a near-infrared (NIR) light source and/or a visible light source;
acquiring multi-spectral images of the region of interest using a multi-wavelength camera;
processing the acquired multi-spectral images to obtain metadata associated with the acquired multi-spectral, images; and
calculating the MetaKG signal from the metadata associated with the acquired multi-spectral images,
wherein calculating the MetaKG signal comprises:
calculating the MetaKG signal using average intensity of speckle contrast images derived from the acquired multi-spectral images to provide an average intensity MetaKG signal;
calculating a frequency MetaKG signal using frequency analysis;
calculating a time-frequency MetaKG signal using time-frequency analysis; and/or
calculating a multi-spectral MetaKG signal using multi-spectral signal processing to remove motion artifacts and improve signal quality;
wherein calculating the time-frequency MetaKG comprises:
separating the MetaKG signal into a cardiac related signal and a respiratory related signal to provide a cardiac MetaKG and a respiratory MetaKG;
determining a specific frequency range for two-dimensional frequency time signals using a power spectral density analysis of the MetaKG signal; and
reconstructing each MetaKG by averaging the determined specific frequency range of the two-dimensional frequency-time signals; and
wherein at least one of illuminating, acquiring, processing and calculating is performed by at least one processor.
2. The method of claim 1 , further comprising one of:
deriving the average intensity MetaKG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG signal from raw multi-spectral images; or
deriving the average intensity MetaKG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG signal from multi-spectral perfusion images.
3. The method of claim 1 , further comprising acquiring blood flow and perfusion data using one or more of the calculated average intensity MetaKG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG signal.
4. The method of claim 3 , wherein the average intensity of the speckle contrast images is average contrast intensity versus time from the speckle contrast images in the region of interest.
5. The method of claim 4 , further comprising calculating at least one of heart rate and pulsatility information from the average contrast intensity versus time in the region of interest by analyzing a frequency component of the average contrast intensity versus time.
6. The method of claim 5 , further comprising:
differentiating between abnormal and normal tissue based on the frequency component of the average contrast intensity versus time; and
indicating a degree of abnormality related to an underlying physiological response.
7. The method of claim 5 , further comprising extracting heart rate variability (HRV) information from the heart rate calculated from the average contrast intensity versus time in the region of interest.
8. The method of claim 1 , further comprising:
changing configuration of the region of interest; and
generating a two dimensional heart rate map of the region of interest in a field of view.
9. The method of claim 8 , wherein changing the configuration of the region of interest comprises changing at least one of a size or a location of the region of interest.
10. The method of claim 1 , wherein the sample comprises one of tissue or an organ.
11. The method of claim 3 , further comprising determining at least one physiologic status parameter including Heart Rate (HR); heart rate variability (HRV); R-to-R interval (RRI); RRI Standard Deviation (RRISD); systolic Blood Pressure threshold (SBt); diastolic blood pressure threshold (DBt); rate×pressure product (RPP); instantaneous perfusion in systole and diastole; frequency analysis and time-frequency analysis of a perfusion curve; and contractility index including slope of the perfusion curve based on the calculated average intensity MetaKG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG signal.
12. The method of claim 1 , further comprising determining at least one physiologic status parameter including at least one of tissue oxygen content, hemoglobin content, and temperature based on the calculated average intensity Met KG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG.
13. A computer system for calculating a MetaKG signal, the system comprising:
a processor; and
a memory coupled to the processor and comprising computer readable program code that when executed by the processor causes the processor to:
direct at least one multi-wavelength light source to illuminate a region of, interest in a sample, wherein the at least one multi-wavelength light source is a near-infrared (NIR) light source and/or a visible light source;
process acquired multi-spectral images of the region of interest to obtain metadata associated with the acquired multi-spectral images, the multi-spectral images being acquired with a multi-wavelength camera; and
calculate the MetaKG signal from the metadata associated with the multi-spectral images, wherein the computer readable program code that causes the processor to calculate the MetaKG signal further comprises computer readable program code that when executed by the processor causes the processor to:
calculate the MetaKG signal using average intensity of speckle contrast images derived from the acquired multi-spectral images to provide an average intensity MetaKG signal;
calculate a frequency MetaKG signal using frequency analysis;
calculate a time-frequency MetaKG signal using time-frequency analysis; and/or
calculate a multi-spectral MetaKG signal using multi-spectral signal processing to remove motion artifacts and improve signal quality, wherein the computer system further comprises computer readable program code to calculate the time-frequency MetaKG by causing the processor to:
separate the MetaKG signal into a cardiac related signal and a respiratory related signal to provide a cardiac MetaKG and a respiratory MetaKG;
determine a specific frequency range for two-dimensional frequency time signals using a power spectral density analysis of the MetaKG signal; and
reconstruct each MetaKG by averaging the determined specific frequency range of the two-dimensional frequency-time signals.
14. The system of claim 13 , wherein the processor further performs operations comprising acquiring blood flow and perfusion data using the calculated average intensity MetaKG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG signal.
15. The system of claim 14 , wherein the average intensity of the speckle contrast images is average contrast intensity versus time in the region of interest.
16. The system of claim 15 , wherein the processor further performs operations comprising calculating at least one of heart rate and pulsatility information from the average intensity versus time in the region of interest by analyzing a frequency component of the average intensity versus time.
17. The system of claim 16 , wherein the processor further performs operations comprising:
differentiating between abnormal and normal tissue based on the frequency component of the average intensity versus time; and
indicating a degree of abnormality related to an underlying physiological response.
18. The system of claim 16 , wherein the processor is further configured to extract heart rate variability (HRV) information from the heart rate calculated from the average intensity versus time in the region of interest.
19. The system of claim 13 , wherein the processor further performs operations comprising:
changing configuration of the region of interest; and
generating a two dimensional heart rate map of the region of interest in a field of view.
20. The system of claim 19 , wherein the processor further performs operations comprising directing the multi-wavelength camera to change at least one of a size or avocation of the region of interest.
21. A computer program product for calculating a MetaKG signal, the computer program product comprising:
a non-transitory computer readable storage medium having computer readable program code embodied in the medium, the computer readable program code comprising:
computer readable program code to direct at least one multi-wavelength light source to illuminate a region of interest in a sample, wherein the multi-wavelength light source is a near-infrared (NIR) light source and/or a visible light source;
computer readable program code to process multi-spectral images of the region of interest obtained using a multi-wavelength camera to obtain metadata associated with the multi-spectral images; and
computer readable program code to calculate the MetaKG signal from the metadata associated with the multi-spectral images, wherein the computer readable program code to calculate the MetaKG signal comprises:
computer readable program code to calculate the MetaKG signal using average intensity of speckle contrast images derived from the acquired multi-spectral images to provide an average intensity MetaKG signal;
computer readable program code to calculate a frequency MetaKG signal using frequency analysis;
computer readable program code to calculate a time-frequency MetaKG signal using time-frequency analysis; and/or
computer readable program code to calculate a multi-spectral MetaKG signal using multi-spectral signal processing to remove motion artifacts and improve signal quality,
wherein the computer readable program code to calculate the time-frequency MetaKG comprises:
computer readable program code to separate the MetaKG signal into a cardiac, related signal and a respiratory related signal to provide a cardiac MetaKG and a respiratory MetaKG;
computer readable program code to determine a specific frequency range for two-dimensional frequency time signals using a power spectral density analysis of the MetaKG signal; and
computer readable program code to reconstruct each MetaKG by averaging the determined specific frequency range of the two-dimensional frequency-time signals.
22. The computer program product of claim 21 , further comprising computer readable program code to acquire blood flow and perfusion data using the calculated average intensity MetaKG signal, the frequency MetaKG signal, the time-frequency MetaKG signal and/or the multi-spectral MetaKG signal.
23. The computer program product of claim 22 , wherein the computer readable program code to calculate the average intensity MetaKG signal calculates the average intensity as average intensity versus time in the region of interest.
24. The computer program product of claim 23 , further comprising computer readable program code to calculate at least one of heart rate and pulsatility information from the average intensity versus time in the region of interest by analyzing a frequency component of the average intensity versus time.
25. The computer program product of claim 24 , further comprising:
computer readable program code to differentiate between abnormal and normal tissue based on the frequency component of the average intensity versus time; and
computer readable program code to indicate a degree of abnormality related to an underlying physiological response.
26. The computer program product of claim 24 , further comprising computer readable program code to extract heart rate variability (HRV) information from the heart rate calculated from the average intensity versus time in the region of interest.
27. The computer program product of claim 21 , further comprising:
computer readable program code to direct the multi-wavelength camera to change configuration of the region of interest; and
computer readable program code to generate a two dimensional heart rate map of a region of interest in a field of view.
28. The computer program product of claim 27 , wherein the computer readable program code to change the configuration of the region, of interest comprises computer readable program code to direct the camera to change at least one of a size or a location of the region of interest.
29. The method of claim 1 , wherein a frequency specific MetaKG(MetaKG F1-F2 (t)) is calculated as:
MetaKG
F
1
-
F
2
(
t
)
=
∑
f
=
F
1
F
2
a
×
TF
(
f
,
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+
b
F
2
-
F
1
wherein TF(f,t) is a frequency-time transform of the average intensity versus time signal; F1 and F2 are lower and upper limits of a specific frequency range, respectively; and a and b are parameters for normalization.
30. A method for calculating a MetaKG signal, the method comprising:
illuminating a region of interest in, a sample with at least one multi-wavelength light source, wherein the multi-wavelength light source is a near-infrared (NIR) light source and/or a visible light source;
acquiring multi-spectral images of the region of interest using a multi-wavelength camera;
processing the acquired multi-spectral images to obtain metadata associated with the acquired multi-spectral images; and
calculating the MetaKG signal from the metadata associated with the acquired multi-spectral images,
wherein calculating the MetaKG signal comprises:
calculating the MetaKG signal using average intensity of speckle contrast images derived from the acquired multi-spectral images to provide an average intensity MetaKG signal;
calculating a frequency MetaKG signal using frequency analysis;
calculating a time-frequency MetaKG signal using time-frequency analysis; and/or calculating a multi-spectral MetaKG signal using multi-spectral signal processing to remove motion artifacts and improve signal quality,
wherein calculating a multi-spectral MetaKG signal comprises:
calculating a residual MetaKG(Meta KGλ1λ2 (t)) as:
MetaKG
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1
,
λ
2
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t
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=
∑
y
=
1
M
∑
x
=
1
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b
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or
MetaKG
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Img
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wherein Img λ1 (x,y,t) is raw or speckle contrast images of a first wavelength; Img λ2 (x,y,t) is raw or speckle contrast images of a second wavelength; a, b and c are parameters for normalization; and M and N are a number of pixels along x and y axes, respectively.
31. The method of claim 30 , wherein the multi-spectral MetaKG is used to determine physiologic, status parameters (PSPs) by determining specific quantitative aspects of the multi-spectral MetaKG that represent one or more PSPs.
32. The method of claim 31 , wherein the PSPs comprise Heart Rate (HR); heart rate variability (HR V); R-to-R interval (RRI); RRI Standard Deviation (RRISD); systolic Blood Pressure threshold (SBt); diastolic blood pressure threshold (DBt); rate×pressure product (RPP); instantaneous perfusion in systole and diastole; frequency analysis and time-frequency analysis of a perfusion curve; and/or contractility index including slope of the perfusion curve based on the calculated MetaKG signal.
33. The method of claim 32 , wherein the multispectral MetaKG generates a specific value that represents a relative perfusion quantification for a pixel at a single point in time, wherein differences at the single point in time between MetaKG values can differentiate thresholds for PSPs, the method further comprising observing a change in the MetaKG for the pixel to provide a different representation of physiology status.