Multispectral medical imaging devices and methods thereof

Patent metadata

Field	Value
Publication number	US-9968285-B2
Application number	US-201414341103-A
Country	US
Kind code	B2
Filing date	Jul 25, 2014
Priority date	Jul 25, 2014
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

A multispectral medical imaging device includes illumination devices arranged to illuminate target tissue. The illumination devices emit light of different near-infrared wavelength bands. The device further includes an objective lens, a near-infrared image sensor positioned to capture image frames reflected from the target tissue, and a visible-light image sensor positioned to capture image frames reflected from the target tissue. A processor is configured to modulate near-infrared light output of the plurality of illumination devices to illuminate the target tissue. The processor is further configured to determine reflectance intensities from the image frames captured by the near-infrared image sensor and to generate a dynamic tissue oxygen saturation map of the target tissue using the reflectance intensities. The device further includes an output device connected to the processor for displaying the dynamic tissue oxygen saturation map.

First claim

What is claimed is:

1. A multispectral medical imaging device comprising:
a plurality of illumination devices arranged to illuminate a target tissue, the plurality of illumination devices comprising near-infrared illumination devices configured to emit light of different near-infrared wavelength bands and a visible-light illumination device configured to emit visible light to illuminate the target tissue;
an objective lens;
a near-infrared image sensor positioned to sequentially capture image frames of near-infrared light reflected from the target tissue through the objective lens;
a visible-light image sensor positioned to capture image frames of visible light reflected from the target tissue through the objective lens;
an image capture buffer coupled to the near-infrared image sensor and the visible-light image sensor, the image capture buffer configured to store the image frames sequentially captured by the near-infrared image sensor and the image frames captured by the visible-light image sensor;
a processor connected to the near-infrared image sensor, the visible-light image sensor, the plurality of illumination devices, and the image capture buffer, the processor configured to modulate near-infrared light output of the plurality of illumination devices to illuminate the target tissue by sequentially driving the near-infrared illumination devices to emit light of the different near-infrared wavelength bands, the processor further configured to:
perform rolling processing on the image frames sequentially captured by the near-infrared image sensor that are stored in the image buffer to form output frames, each output frame comprising an image frame sequentially captured by the near-infrared image sensor for each one of the different near-infrared wavelength bands emitted by the near-infrared sensor;
use the near-infrared image sensor to capture an ambient infrared image frame of the target tissue when controlling all of the illumination devices to not illuminate the target tissue;
for each respective output frame, subtract the ambient infrared image frame from each image frame of the respective output frame;
determine reflectance intensities from the image frames;
perform delta processing on the reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame to generate delta processed reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame; and,
combine the delta processed reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame to generate a dynamic tissue oxygen saturation map of the target tissue; and

an output device connected to the processor for displaying the dynamic tissue oxygen saturation map.

2. The device of claim 1 , wherein the processor is configured to perform delta processing on the reflective intensities for each one of the different near-infrared wavelength bands for each respective output frame by comparing the reflectance intensities for each one of the different near-infrared wavelength bands for each respective output frame to a reference standard for each one of the different near-infrared wavelength bands.

3. The device of claim 1 , wherein the plurality of illumination devices are arranged in a ring around the objective lens.

4. The device of claim 1 , wherein the plurality of illumination devices comprises at least four near-infrared illumination devices having near-infrared wavelength bands with nominal peak wavelengths of 740, 780, 850 and 940 nm.

5. The device of claim 1 , further comprising a dichroic beam splitter positioned between the objective lens and the near-infrared and visible-light image sensors, the dichroic beam splitter arranged to split light from the objective lens between the near-infrared and visible-light image sensors.

6. The device of claim 1 , wherein the visible light illumination device comprises a white-light illumination device arranged to illuminate the target tissue with white light.

7. The device of claim 1 , wherein the output device comprises a display for displaying the dynamic tissue oxygen saturation map on an image of the target tissue for viewing by a clinician.

8. The device of claim 1 , wherein the output device comprises a projector positioned to project the dynamic tissue oxygen saturation map onto a skin surface over the target tissue.

9. The device of claim 1 , wherein the processor is configured to periodically drive the visible-light illumination device to emit visible light to illuminate the target tissue.

10. The device of claim 9 , wherein a frame rate of the dynamic tissue oxygen saturation map is equal to a combined frequency of modulation of all of the plurality of illumination devices.

11. The device of claim 1 , wherein the processor is further configured to perform motion correction on the image frames captured by the near-infrared image sensor, the motion correction comprising selecting a reference frame from the image frames and calculating image registration coefficients for at least one subsequent image frame of the image frames.

12. The device of claim 11 , wherein calculating image registration coefficients comprises performing a space transformation on the reference frame and the at least one subsequent image frame.

13. The device of claim 11 , wherein calculating image registration coefficients comprises performing feature detection on the reference frame and the at least one subsequent image frame.

14. The device of claim 11 , wherein the processor is further configured to calculate image registration coefficients for the motion correction using sub-regions of the image frames captured by the near-infrared image sensor, the sub-regions having dimensions smaller than a size of the image frames and being located away from edges of the image frames.

15. The device of claim 11 , wherein the processor is further configured to perform motion correction on the visible-light image frames captured by the visible-light image sensor.

16. The device of claim 15 , wherein the motion correction comprises performing feature detection including detection of an ink mark on a skin surface over the target tissue.

17. The device of claim 15 , wherein the motion correction comprises performing feature detection including detection of body hair on skin over the target tissue.

18. The device of claim 17 , wherein the motion correction comprises performing feature detection including detection of vasculature of the target tissue.

19. The device of claim 1 , wherein the processor is further configured to use the visible-light image frames to determine a correction for melanin in skin over the target tissue and to apply the correction to the reflectance intensities determined from the image frames captured by the near-infrared image sensor.

20. The device of claim 19 , wherein the processor is configured to determine the correction from a predetermined relationship between visible light reflected intensity determined from the visible light frames and melanin concentration.

21. The device of claim 1 , wherein the processor is further configured to repeatedly capture ambient infrared image frames and, for each respective output frame, to subtract a most recent ambient infrared image frame from the image frames of the respective output frame.

22. The device of claim 1 , wherein the processor is further configured to trigger capture of th

Assignees

• Christie Digital Systems Usa

Inventors

• Valsan Gopal
• Zarei Mahmoodabadi Sina
• Wagner Robert Benjamin
• Priest David
• Amelard Robert

Classifications

• G16H30/40

  for processing medical images, e.g. editing · CPC title

• A61B5/14551 Primary

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• A61B5/0261

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• A61B5/742

  using visual displays (displays for heart-related electrical signals, e.g. ECG, A61B5/339) · CPC title

• A61B5/7207

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