Method for evaluating blush in myocardial tissue

• US 9,936,887 B2
• Filed: 03/31/2017
• Issued: 04/10/2018
• Est. Priority Date: 01/25/2008
• Status: Active Grant

• Current Assignee: Stryker Corporation
• Original Assignee: Novadaq Technologies ULC (Stryker Corporation)
• Inventors: Dvorsky, Peter, Goyette, David Mark Henri, Ferguson, Jr., T. Bruce, Chen, Cheng
• Primary Examiner(s): ROZANSKI, MICHAEL T
• Application Number:
  US15/476,290
• Publication Number:
  US 20180020933A1
• Time in Patent Office: 375 Days
• CPC Class Codes: A61B 2576/02 specially adapted for a particular organ or body part
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0275 using tracers, e.g. dye dilution
• CPC Class Codes: A61B 5/489 Blood vessels
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 6/503 for diagnosis of the heart
• CPC Class Codes: A61B 6/504 for diagnosis of blood vessels, e.g. by angiography
• CPC Class Codes: A61B 6/507 for determination of haemodynamic parameters, e.g. perfusion CT
• CPC Class Codes: A61M 5/007 for contrast media
• CPC Class Codes: G06T 2207/10064 Fluorescence image
• CPC Class Codes: G06T 2207/30104 Vascular flow; Blood flow; Perfusion
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/12 Edge-based segmentation
• CPC Class Codes: G06T 7/248 involving reference images or patches
• CPC Class Codes: G06T 7/90 Determination of colour characteristics

Abstract

Vessel perfusion and myocardial blush are determined by analyzing fluorescence signals obtained in a static region-of-interest (ROI) in a collection of fluorescence images of myocardial tissue. The blush value is determined from the total intensity of the intensity values of image elements located within the smallest contiguous range of image intensity values containing a predefined fraction of a total measured image intensity of all image elements within the ROI. Vessel (arterial) peak intensity is determined from image elements located within the ROI that have the smallest contiguous range of highest measured image intensity values and contain a predefined fraction of a total measured image intensity of all image elements within the ROI. Cardiac function can be established by comparing the time differential between the time of peak intensity in a blood vessel and that in a region of neighboring myocardial tissue both pre and post procedure.

Claims

1. A method for determining perfusion in tissue using fluorescence imaging, comprising:

defining a static region of interest (ROI) in an image of the tissue;

measuring fluorescence intensity values of image elements (pixels) located within the ROI; and

determining a blush value from an average of the intensity values of image elements located within a smallest contiguous range of image intensity values containing a first predefined fraction of a total measured image intensity of all image elements within the ROI.

2. The method of claim 1, wherein the smallest range of contiguous image intensity values is determined from a histogram of a frequency of occurrence of the measured image intensity values.

3. The method of claim 1, wherein the first predefined fraction is between 70% and 30%, preferably between 60% and 40%, and most preferably at about 50%.

4. The method of claim 1, wherein blush values are determined over a predefined period of time.

5. The method of claim 4, wherein the blush values are determined continuously over the predefined period of time.

6. The method of claim 4, further comprising determining a blush rate from a slope of the blush values.

7. The method of claim 4, further comprising determining a washout rate from a slope of the blush values.

8. The method of claim 1, further comprising

defining a second static ROI in the image of the tissue, with the second ROI including an arterial blood vessel, and

determining a measure of peak intensity of the arterial blood vessel from a total intensity of intensity values of image elements located within a smallest contiguous range of high image intensity values containing a second predefined fraction of a total measured image intensity of brightest image elements within the second ROI.

9. The method of claim 8, wherein the second predefined fraction is approximately 20%.

10. The method of claim 8, further comprising determining an outcome of a procedure by comparing an elapsed time between a maximum blush value and maximum measure of perfusion before the procedure and an elapsed time between a maximum blush value and maximum measure of perfusion after the procedure.