Multi-spectral laser imaging (MSLI) methods and systems for blood flow and perfusion imaging and quantification

• US 10,058,256 B2
• Filed: 02/26/2016
• Issued: 08/28/2018
• Est. Priority Date: 03/20/2015
• Status: Active Grant

• Current Assignee: East Carolina University (University of North Carolina System)
• Original Assignee: East Carolina University (University of North Carolina System)
• Inventors: Chen, Cheng, Ferguson, Jr., T. Bruce, Peng, Zhiyong, Jacobs, Kenneth Michael
• Primary Examiner(s): Voorhees, Catherine
• Assistant Examiner(s): Patel, Natasha
• Application Number:
  US15/054,830
• Publication Number:
  US 20160270672A1
• Time in Patent Office: 914 Days
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/0035 adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography
• CPC Class Codes: A61B 5/0077 Devices for viewing the surface of the body, e.g. camera, magnifying lens
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence
• CPC Class Codes: G16H 30/40 for processing medical images, e.g. editing

Abstract

Some embodiments of the present inventive concept provide a system that uses two wavelengths of differential transmittance through a sample to apply laser speckle or laser Doppler imaging. A first of the two wavelengths is within the visible range that has zero or very shallow penetration. This wavelength captures the anatomical structure of tissue/organ surface and serves as a position marker of the sample but not the subsurface movement of blood flow and perfusion. A second wavelength is in the near Infra-Red (NIR) range, which has much deeper penetration. This wavelength reveals the underlying blood flow physiology and correlates both to the motion of the sample and also the movement of blood flow and perfusion. Thus, true motion of blood flow and perfusion can be derived from the NIR imaging measurement without being affected by the motion artifact of the target.

Claims

1. A multispectral imaging system, the system comprising:

a first light source, the first light source being one of coherent, non-coherent and partially coherent, the first light source having a first wavelength configured to produce a non-coherent illumination to image a sample;

a second coherent light source, different from the first light source, having a second wavelength, different from the first wavelength, configured to image the sample simultaneously with the first light source;

a camera configured to simultaneously receive information related to the first and second light sources from the sample, wherein light at the first wavelength is configured to image a surface of the sample into the camera and light at the second wavelength is configured to penetrate the sample and provide information related to the penetrated sample to the camera; and

a processor configured to combine the received information related to the first and second light sources and generate a synthesized image of the sample comprising surface anatomical structure and sub-surface physiology of blood flow and perfusion of the sample in terms of a blood flow rate distribution.

2. The system of claim 1, wherein the first and second wavelengths have different wavelengths in a range from 350 nm to 1100 nm.

3. The system of claim 2, wherein the first wavelength is in one of an ultraviolet (UV) and a visible spectrum and the second wavelength is in one of a visible and near infrared spectrum.

4. The system of claim 1, wherein the sample is an in vivo sample and comprises at least one of tissue and an organ.

5. The system of claim 1, wherein the processor is further configured to reconstruct a color image depicting a surface anatomical view of the sample using at least one monochromatic camera in real time and direct a display in communication with the processor to display the color image simultaneously with a sub-surface blood flow and perfusion distribution map in real time.

6. The system of claim 1, wherein the processor is further configured to use coherent light of wavelength in one of a visible and a near infrared (NIR) spectrum to replace a red color spectrum to provide deeper sub-surface tissue information in the synthesized image.

7. The system of claim 1, wherein an output of the system provides a general sub-surface blood flow speed distribution map and surface anatomical structure simultaneously in real time.

8. The system of claim 1, wherein the processor is further configured to calculate sub-surface blood flow rate or rates from a measured distribution of velocity in a field of view of the sample for the sub-surface blood flow rate distribution.

9. The system of claim 1, wherein the processor is further configured to separate motion of the sample determined from surface anatomical structure from motion of sub-surface blood flow and perfusion in the synthesized image.

10. The system of claim 1, wherein the processor is further configured to remove motion artifacts of the imaged sample caused by sample movement in order to improve accuracy of quantification of sub-surface blood flow and perfusion,

wherein the blood flood flow and perfusion of the sample relative to a host tissue/organ including blood vessels is calculated using the following equation:

v₁₂(r)=v₁₃(r)+v₃₂(r)=v₁₃(r)−

v₂₃(r),

wherein v₁₂(r) is the blood flood flow and perfusion of the sample relative to the host tissue/organ;

v₁₃(r) is a velocity distribution of the sample relative to the camera;

v₃₂(r) is a velocity distribution of the camera relative to the host tissue/organ; and

v₂₃(r) is a velocity distribution of the host tissue/organ relative to the camera.

11. The system of claim 1, wherein the processor is further configured to remove motion artifact of the imaged sample caused by movement of an imaging platform holding the camera and/or the camera in order to improve accuracy of quantification of blood flow and perfusion.

12. The system of claim 1, wherein the first light source comprises a non-coherent light source or a laser with coherent length of laser illumination significantly reduced, and wherein the processor is further configured to improve quantification accuracy in coherent illumination based on blood flow and perfusion technologies by removing motion artifacts of the imaged sample.

13. The system of claim 12, wherein the multi-spectral imaging system is configured as a laser-based blood flow and perfusion measuring system comprising one or more of laser speckle imaging (LSI), laser Doppler imaging (LDI), Florescence imaging, reflectance imaging and/or LSI plus Fluorescence imaging.

14. The system of claim 12, wherein the processor is further configured to improve quantification accuracy in laser-based blood flow and perfusion measuring technologies by removing static background noise caused by a difference of optical characteristics of an inhomogeneous scattering media.

15. The system of claim 1, wherein the processor is further configured to direct a display in communication with the processor to display the synthesized image with the surface anatomical structure and the physiology of sub-surface blood flow and perfusion of the sample simultaneously in real time.

16. The system of claim 1, wherein the camera is further configured to receive information related to more than two wavelengths, and wherein each of the more than two wavelengths provides data related to the surface anatomical structure and sub-surface blood flow physiology at corresponding different depths in the sample.

17. The system of claim 1, wherein the first wavelength is configured to image the surface and extend from between 300 nm to 600 nm into the sample and the second wavelength is configured to penetrate the sample from between 500 nm to 1500 nm.

18. The system of claim 1, wherein the system is configured to image a macro field of view (FOV).

19. The system of claim 1, wherein the camera comprises a camera including one of split sensors or multiple sensors, and wherein the one of the split sensors and multiple sensors are configured to simultaneously receive multiple wavelength images as the received information related to the first and second light sources.

20. The system of claim 1, wherein a velocity of the sample is calculated using the following equation:

21. A method for multispectral imaging in a multispectral imaging system, the method comprising:

simultaneously imaging a sample using a first light source having a first wavelength configured to produce a non-coherent illumination and a second coherent light source, different from the first light source, having a second wavelength, different from the first wavelength;

receiving information related to the first and second light sources simultaneously from the sample at a camera, wherein light at the first wavelength is configured to reflect off a surface of the sample into the camera and light at the second wavelength is configured to penetrate the sample and provide information related to the penetrated sample to the camera; and

combining the received information related to the first and second light sources to generate a synthesized image of the sample comprising surface anatomical structure and sub-surface physiology of blood flow and perfusion of the sample in terms of a blood flow rate distribution,

wherein at least one of the imaging, receiving and combining are performed by at least one processor.

22. The method of claim 21, wherein the first wavelength is in one of an ultraviolet (UV) and a visible spectrum and the second wavelength is in one of a visible and a near infrared spectrum.

23. A computer program product for multispectral imaging in a multispectral imaging system, 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 a first light source to transmit light onto a sample, the first light source having a first wavelength configured to produce a non-coherent illumination and direct a second light source to transmit light into the sample, the second light source being different from the first light source and having a second wavelength configured to produce coherent illumination, different from the first wavelength,

wherein light at the first wavelength is configured to reflect off a surface of the sample into a camera and provide information regarding the sample to the camera and light at the second wavelength is configured to penetrate the sample and provide information related to the penetrated sample to the camera simultaneously with the information from the first wavelength; and

computer readable program code to combine the information related to the first and second light sources received simultaneously by the camera to generate a synthesized image of the sample comprising surface anatomical structure and physiology of sub-surface blood flow and perfusion of the sample in terms of blood flow rate distribution.