Chronic total occlusion crossing devices with imaging

1. An imaging device comprising:

an outer sheath including an optically clear annular section at a distal end thereof;

a hollow flexible shaft configured to be inserted within the outer sheath and rotated relative thereto, the hollow flexible shaft having an imaging window therein;

an optical fiber extending within the hollow flexible shaft substantially along the central axis, a distal tip of the optical fiber attached to the hollow flexible shaft and aligned with the imaging window so as to transfer an optical coherence tomography signal through the imaging window.

2. The imaging device of claim 1 , wherein the optical fiber extends substantially along the central axis for the entire length of the fiber.

3. The imaging device of claim 1 , wherein the device is less than 0.1 inches in diameter.

4. The imaging device of claim 3 , wherein the device is less than 0.08 inches in diameter.

5. The imaging device of claim 4 , wherein the device is less than 0.05 inches in diameter.

6. The imaging device of claim 1 , wherein the hollow flexible shaft is made of tungsten.

7. The imaging device of claim 1 , wherein the hollow flexible shaft is made of multiple layers of wound filars.

8. The imaging device of claim 7 , wherein the filars are counterwound.

9. The imaging device of claim 1 , wherein the hollow flexible shaft further includes a mirror therein configured to reflect light from the optical fiber into adjacent tissue.

10. The imaging device of claim 1 , wherein the optically clear annular section comprises tecothane or fluorinated ethylene propylene.

11. The imaging device of claim 1 , wherein the optically clear annular section has a refractive index of between 1.35 and 1.45.

12. The imaging device of claim 1 , wherein the imaging device further comprises a cutter thereon.

13. A method of imaging a body lumen, the method comprising:

inserting an outer sheath into the body lumen, the outer sheath having an optically clear annular section at a distal end thereof;

inserting an imaging device into a lumen of the other sheath, the imaging device including a hollow flexible shaft having a central longitudinal axis with an imaging window therein and an optical fiber extending within the hollow flexible shaft, wherein a distal tip of the optical fiber is attached to the hollow flexible shaft and aligned with the imaging window, the optical fiber extending substantially along the central longitudinal axis;

rotating the hollow flexible shaft within the lumen of the outer sheath; and

collecting images of the body lumen through the imaging window and the optically clear annular section with the optical fiber as the hollow flexible shaft rotates.

14. The method of claim 13 , wherein collecting images of the body lumen comprises collecting images of the body lumen at rates of greater than 10 frames per minute.

15. The method of claim 13 , wherein the body lumen is a coronary artery.

16. The method of claim 13 , wherein the body lumen is a peripheral artery.

17. The method of claim 13 , wherein the imaging device includes a cutter thereon, the method further comprising cutting tissue of the body lumen with the cutter to pass through an occlusion in the body lumen.

18. The method of claim 17 , further comprising removing the imaging device from the lumen of the outer sheath and advancing a guidewire through the lumen of the outer sheath after passing the cutter through the occlusion.

19. The method of claim 13 , wherein the step of collecting images is performed without extending the hollow flexible shaft distally past the outer sheath.