CATHETER-BASED OFF-AXIS OPTICAL COHERENCE TOMOGRAPHY IMAGING SYSTEM

• US 20110021926A1
• Filed: 07/01/2010
• Published: 01/27/2011
• Est. Priority Date: 07/01/2009
• Status: Active Grant

• Current Assignee: Avinger Inc.
• Original Assignee: Avinger Inc.
• Inventors: Chan, Kin F., Spinelli, Nicholas J., White, Christopher B., Rosenthal, Michael H., McNall, Charles W., Ngo, Benjamin, Black, John F., Lumabas, Evangeline, Jackson, Dennis W., Zung, Michael, SPENCER, Maegan K., Simpson, John B.
• Granted Patent: US 9,125,562 B2
• Time in Patent Office: Days
• US Class Current: 600/478
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/0066 Optical coherence imaging
• CPC Class Codes: A61B 5/0073 by tomography, i.e. reconstruction of 3D images from 2D projections A61B5/0066 takes precedence
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

Catheter-based Optical Coherence Tomography (OCT) systems utilizing an optical fiber that is positioned off-axis of the central longitudinal axis of the catheter have many advantage over catheter-based OCT systems, particularly those having centrally-positioned optical fibers or fibers that rotate independently of the elongate body of the catheter. An OCT system having an off-axis optical fiber for visualizing the inside of a body lumen may be rotated with the body of the elongate catheter, relative to a handle portion. The handle may include a fiber management pathway for the optical fiber that permits the off-axis optical fiber to rotate with the catheter body relative to the handle. The system may also include optical processing elements adapted to prepare and process the OCT image collected by the off-axis catheter systems described herein.

Claims

1. An Optical Coherence Tomography (OCT) catheter device for visualizing a body lumen by rotation of the catheter and an off-axis optical fiber within the catheter, the device comprising:

a catheter body having an elongate proximal to distal length;

an optical fiber extending the length of the catheter body along a path that is off-axis of the elongate length of the catheter body;

a proximal handle rotationally coupled to the catheter body; and

a fiber management pathway within the handle configured to allow the off-axis optical fiber to rotate with the catheter body, relative to the handle.

2. The device of claim 1, wherein the catheter body comprises a central lumen.

3. The device of claim 1, wherein the catheter body comprises an optical fiber channel for the optical fiber, the channel located off-axis of the elongate length of the catheter body.

4. The device of claim 1, further comprising a rotation knob coupled to the catheter body and configured to be rotated to rotate the catheter body.

5. The device of claim 1, wherein the handle comprises a limiter configured to limit rotation of the catheter body.

6. The device of claim 5, wherein the limiter is configured to prevent rotation of the catheter body more than between about two to about six full rotations.

7. The device of claim 5, wherein the limiter is configured to prevent rotation of the catheter body more than four full rotations.

8. The device of claim 5, wherein the limiter is configured to prevent rotation of the catheter body more than five full rotations.

9. The device of claim 1, wherein the rotation knob is configured to rotate the catheter body by a ratio of greater than one times the rotation of the rotation knob.

10. The device of claim 1, wherein the rotation knob is configured to rotate the catheter body by a ratio of between about 1.5 and about five times the rotation of the rotation knob.

11. The device of claim 1, wherein the rotation knob is configured to rotate the catheter body by a ratio of about four times the rotation of the rotation knob.

12. The device of claim 1, further comprising a side-facing port optically coupled to the distal end region of the optical fiber.

13. The device of claim 1, wherein the optical fiber is fixedly attached to the distal end region of the catheter.

14. The device of claim 1, wherein the optical fiber is only fixedly attached in the catheter body to a single position in the distal end region of the catheter, and is otherwise free to move longitudinally relative to the elongate length of the catheter body.

15. The device of claim 1, further comprising a rotational encoder configured to encode the rotational position of the catheter body.

16. The device of claim 1, wherein the fiber management pathway comprises a helically arranged channel having a plurality of turns.

17. The device of claim 1, wherein the fiber management pathway comprises a helically arranged channel having a plurality of turns, wherein the channel comprises walls having an upper radial height and a lower radial height.

18. The device of claim 17, wherein the fiber management is configured so that the fiber does not contact the upper radial height or the lower radial height of the helically-arranged channel.

19. The device of claim 1, wherein the fiber management pathway is configured so that the fiber does not traverse a bend radius of less than the light leakage minimum bend radius for the optical fiber.

20. The device of claim 1, wherein the fiber management pathway is configured so that the fiber does not traverse a bend radius of less than about 5 mm.

21. An Optical Coherence Tomography (OCT) catheter device for visualizing a body lumen by rotation of the catheter and an off-axis optical fiber within the catheter, the device comprising:

a catheter body having an elongate proximal to distal length;

an optical fiber fixed to a distal end region of the catheter body and extending the length of the catheter body along a path that is off-axis of the elongate length of the catheter body;

a proximal handle rotationally coupled to the catheter body; and

a fiber management pathway comprising a helical channel within the handle having a plurality of turns and an upper radial height and a lower radial height; and

a limiter preventing the optical fiber from exceeding the upper radial height or the lower radial height of the helical channel as the catheter body is rotated relative to the handle.

22. A method of managing an optical fiber for off-axis rotation of an Optical Coherence Tomography (OCT) system, the method comprising:

taking an OCT image using an optical fiber that is fixed to a distal end region of a catheter body and that extends along the length of the catheter body through an off-axis pathway within the catheter body and into a fiber management channel; and

rotating the catheter body relative to the proximal handle so that the catheter body and optical fiber are simultaneously rotated.

23. The method of claim 22, further comprising limiting the rotation of the catheter body so that the optical fiber does not traverse a bend radius of less than the light leakage bend radius for the optical fiber.

24. The method of claim 22, wherein the fiber management pathway is configured so that the optical fiber does not traverse a bend radius of less than about 5 mm.

25. The method of claim 22, further comprising encoding the rotation of the catheter relative to the handle.

26. The method of claim 22, further comprising permitting the fiber to extend longitudinally within a channel extending off-axis along the length of the catheter.

27. The method of claim 22, further comprising limiting the rotation of the catheter body relative to the handle to between about 2 and about 6 full rotations.

28. The method of claim 22, further comprising limiting the rotation of the catheter body relative to the handle to less than about 5 full rotations.

29. The method of claim 22, wherein the step of rotating comprises rotating a rotation knob coupled to the handle to rotate the catheter body relative to the handle.

30. The method of claim 29, wherein the rotation knob is configured to rotate the catheter body by a ratio of greater than one times the rotation of the rotation knob.

31. The method of claim 29, wherein the rotation knob is configured to rotate the catheter body by a ratio of between about 1.5 and about five times the rotation of the rotation knob.

32. A method of managing an optical fiber for off-axis rotation of an Optical Coherence Tomography (OCT) system, the method comprising:

taking an OCT image using an optical fiber that is fixed to a distal end region of a catheter body and that extends along the length of the catheter body through an off-axis pathway within the catheter body and into a fiber management channel within a proximal handle to which the catheter body is rotationally coupled, the channel having a plurality of helical turns and an upper radial height and a lower radial height; and

rotating the catheter body relative to the proximal handle so that the optical fiber within helical turns of the fiber management channel is between the upper radial height and the lower radial height.

33. The method of claim 32, further comprising limiting the rotation of the catheter so that the optical fiber does not coil within the helical turns of the fiber management channel to a height that is greater than the upper radial height or less than the lower radial height.

34. A method of imaging a body lumen by Optical Coherence Tomography (OCT) using an elongate OCT catheter having an OCT sensor fixedly attached to a distal portion of the catheter, the method comprising:

rotating the catheter from a proximal region of the catheter to rotate the OCT sensor at the distal portion while acquiring OCT images using the OCT sensor; and

determining a rotational lag (θ

) for the OCT sensor at the distal portion; and

providing one or more OCT images corrected for the rotational lag.

35. The method of claim 34, wherein the catheter comprises an optical fiber extending off-axis along the length of the catheter.

36. The method of claim 34, wherein the step of rotating the catheter from a proximal region of the catheter comprises rotating the catheter at least 360 degrees in a first rotational direction.

37. The method of claim 34, wherein the step of rotating the catheter from a proximal region of the catheter comprises acquiring a first image while rotating the catheter at least 360 degrees in a first rotational direction and acquiring a second image while rotating the catheter at least 360 degrees in a second rotational direction.

38. The method of claim 34, wherein the step of determining the rotational lag (θ

) comprises comparing an OCT image acquired while rotating in a first rotational direction to an OCT image acquired while rotating in a second rotational direction.

39. The method of claim 34, further comprising storing the rotational lag (θ

) determined for correction of additional OCT images.

40. The method of claim 34, wherein the step of rotating the catheter from the proximal region of the catheter comprises rotating the catheter from the proximal region until motion of the distal region is observed and recording the extent of rotation of the distal region of the catheter.

41. The method of claim 34, wherein the step of rotating the catheter from the proximal region of the catheter comprises rotating the catheter in a first rotational direction and a second rotational direction from the proximal region until motion of the distal region is observed in the first direction and the second rotational direction and recording the extent of rotation of the distal region of the catheter in the first rotational direction and the second rotational directions.

42. The method of claim 41, wherein the step of determining the rotational lag (θ

) comprises determining the difference of the extents of rotation of the distal regions of the catheter in the first rotational direction and the second rotational directions.

43. A method of imaging a body lumen by Optical Coherence Tomography (OCT) using an elongate OCT catheter having a central axis and an OCT sensor fixedly attached off-axis at a distal portion of the catheter, the method comprising:

rotating the OCT sensor at the distal portion while acquiring OCT images using the OCT sensor; and

displaying the OCT images as a toroidal mapping.

44. The method of claim 43, wherein the step of displaying the OCT images comprises determining the toroidal mapping based on the radial position of the OCT sensor relative to the catheter central axis of the catheter.

45. The method of claim 43, further comprising correcting radial distortion in the image by scaling the OCT images.

46. The method of claim 43, further comprising correcting radial distortion in the image by multiplying the radial positions of the OCT images by a correction factor.

47. The method of claim 43, further comprising correcting radial distortion in the image by adding a correction offset to the radial positions of the OCT.

48. The method of claim 43, further comprising correcting radial distortion in the image by applying a mapping table of correction offsets to the radial positions of the OCT.

49. A method of imaging a body lumen by Optical Coherence Tomography (OCT) using an elongate OCT catheter having a central axis and an OCT sensor fixedly attached off-axis at a distal portion of the catheter, the method comprising:

acquiring a first plurality of OCT scan lines using the OCT sensor;

point-wise averaging of data in the first plurality of scan lines;

transforming the averaged first plurality of scan lines by Inverse Fourier Transform; and

displaying the OCT images as a toroidal mapping.

50. The method of claim 49, further comprising repeating the steps of acquiring, point-wise averaging and transforming for multiple pluralities of OCT scan lines.

51. The method of claim 50, further comprising point-wise averaging of the multiple pluralities of OCT scan lines to post-FFT average the OCT image.