Coronary angiography imaging system

• US 4,995,398 A
• Filed: 04/30/1990
• Issued: 02/26/1991
• Est. Priority Date: 04/30/1990
• Status: Expired due to Fees

• Current Assignee: Russell F. Wilson
• Original Assignee: Turnidge, Patrick A.
• Inventors: Turnidge, Patrick A.
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/516,763
• Time in Patent Office: 302 Days
• Field of Search: 128/668, 128/664, 128/736, 128/666, 128/691, 128/633
• US Class Current: 600/508
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence

Abstract

Thermography visually shows small temperature differences in either color or black and white. In heart by-pass operations, thermography is used to determine whether each by-pass is successful (i.e. the patency of the by-pass) and resulting flow directions and profusion during the course of the operation. The methods used include the use of scanning thermal camera, image processing, temperature differentials, and displaying images in real time.

Claims

1. A method of thermal coronary angiography for assessing graft patency, coronary anatomy and perfusion fields in coronary by-pass surgery, which comprises:

(a) positioning a thermal camera between 70°

to 90°

perpendicular to the exposed surface of the heart;

(b) positioning the thermal camera a distance between 0.8 meters to 1.2 meters from the exposed surface of the heart;

(c) setting the thermal camera to the expected temperatures such that expected temperatures are near one of the two ends of the scale;

(d) injecting cold crystalloid cardioplegia into a proximal vein graft; and

(e) recording and displaying images on a monitor in real time.

2. The method of claim 1 wherein the expected temperature is 20°

C.

4. The method of claim 1 wherein the amount of cold crystalloid cardioplegia is 20-30 ml.

5. The method of claim 1 wherein the temperature difference between the exposed surface of the heart and the cold crystalloid cardioplegia is greater than 4°

C.

6. The method of claim 1 where temperature differences can be displayed to a depth of 4 mm.

7. The method of claim 1 additionally comprising:

(f) enhancing said image by a thermal image computer.

8. The method of claim 7 wherein said enhancement is accomplished by image scaling.

9. The method of claim 7 where said enhancement is accomplished by inventing.

10. The method of claim 7 where said enhancement is accomplished by magnifying.

11. The method of claim 7 where said enhancement is accomplished by low pass filtering.

12. The method of claim 7 where said enhancement is accomplished by high pass filtering.

13. The method of claim 7 where said enhancement is accomplished by image subtraction.

14. The method of claim 1 additionally comprising:

(g) stopping an image on the monitor.

15. The method of claim 1 additionally comprising:

(h) storing said images.

16. The method of claim 15 where storing said images was on floppy diskettes.

3. The method of claim wherein the temperature of cold crystalloid cardioplegia is 8°

C. to 14°

C.

17. A method of thermal coronary angiography for assessing graft patency, coronary anatomy and perfusion fields in coronary by-pass surgery, which comprises:

(a) positioning a thermal camera between 70°

to 90°

perpendicular to the exposed surface of the heart;

(b) positioning the thermal camera a distance between 0.8 meters to 1.2 meters from the exposed surface of the heart;

(c) setting the thermal camera to the expected temperatures such that said expected temperatures are near one of the two ends of the scale;

(d) releasing a bulldog clamp on the internal mammary artery;

(e) reperfusing with warmer blood into the internal mammary artery; and

(f) recording and displaying images on a monitor in real time.

18. The method of claim 17 wherein the temperature difference between the exposed surface of the heart and the warmer blood is greater than 4°

C.

19. The method of claim 17 wherein the temperature of warm blood is 25°

C. to 30°

C.

20. The method of claim 17 wherein the expected temperature is 20°

C.

21. The method of claim 17 additionally comprising:

(g) enhancing said image by a thermal image computer.

22. The method of claim 21 wherein said enhancement is accomplished by image scaling.

23. The method of claim 21 where said enhancement is accomplished by inverting.

24. The method of claim 21 where said enhancement is accomplished by magnifying.

25. The method of claim 21 where said enhancement is accomplished by low pass filtering.

26. The method of claim 21 where said enhancement is accomplished by high pass filtering.

27. The method of claim 21 where said enhancement is accomplished by image subtraction.

28. The method of claim 17 additionally comprising:

(h) stopping an image on the monitor.

29. The method of claim 17 additionally comprising:

(i) storing said images.

30. The method of claim 29 where said storing said images is on floppy diskettes.

31. The method of claim 17 where temperature differences can be displayed to a depth of 4 mm.