Catheter

1. A catheter comprising:

a sheath configured to be positioned in a body lumen of a living body, the sheath including a window portion permeable to inspection waves;

a detection unit which receives inspection waves reflected from tissue of the body lumen and passing through the window portion of the sheath, the window portion possessing an axial extent extending from a distal-most end of the window portion to a proximal-most end of the window portion, the detection unit being axially movably positioned inside the sheath;

a drive shaft connected to the detection unit so that axial movement of the drive shaft results in axial movement of the detection unit, the drive shaft being positioned inside the sheath;

reinforcement positionable to axially overlap an entirety of the axial extent of the window portion of the sheath and reinforce a portion of the sheath that includes the entirety of the axial extent of window portion, at least a portion of the reinforcement being axially movable relative to the sheath so that the portion of the reinforcement is movable from a position in axial overlapping relation to the window portion of the sheath to a position in non-axial overlapping relation to the window portion of the sheath;

a hub connected to the drive shaft so that axial movement of the hub results in axial movement of the drive shaft and the detection unit, the hub possessing a proximal-most end; and

the reinforcement possessing a proximal-most end located distally of the proximal-most end of the hub.

2. The catheter according to claim 1 , wherein the detection unit is a transducer unit which transmits ultrasound through the window portion of the sheath and receives reflected ultrasound through the window portion of the sheath.

3. The catheter according to claim 1 , further comprising a rotatable operation dial operatively connected to the portion of the reinforcement so that operation of the operation dial axially moves the portion of the reinforcement.

4. The catheter according to claim 3 , wherein the reinforcement includes a reinforcement tube constituting the portion of the reinforcement that is axially movable, and wherein the operation dial is mounted in a main body, the main body housing a pair of rotation members which are both in contact with an outer surface of the reinforcement tube, one of the rotation members being fixed to the operation dials so that operation of the operation dial results in rotation of the one rotation member.

5. The catheter according to claim 1 , wherein the reinforcement includes a reinforcement tube constituting the portion of the reinforcement that is axially movable, and wherein the reinforcement tube and the detection unit are axially fixed relative to one another so that the reinforcement tube is not axially movable relative to the detection unit, and a distal-most end of the reinforcement tube is positioned proximally of a distal end of the detection unit so that the distal-most end of the detection unit is distal of the distal-most end of the reinforcement tube.

6. The catheter according to claim 1 , wherein the sheath includes a sheath distal member provided with a through hole configured to receive a guide wire to guide movement of the catheter toward a target site in the body lumen.

7. A catheter comprising:

a sheath configured to be positioned in a body lumen of a living body and provided with a window portion permeable to inspection waves, the window portion of the sheath possessing an inner surface and an outer surface, the window portion possessing an axial extent extending from a distal-most end of the window portion to a proximal-most end of the window portion;

a detection unit which detects the inspection waves passing through the window portion of the sheath, the detection unit being positioned inside the sheath and being axially movable inside the sheath; and

reinforcement being configured to cover an entirety of the axial extent of the window portion, at least a portion of the reinforcement being axially movable relative to the sheath so that the portion of the reinforcement is movable from a position in covering relation to the window portion of the sheath in which the portion of the reinforcement covers the inner or the outer surface of the window portion of the sheath, to a position in non-covering relation to the window portion in which the portion of the reinforcement covers neither the inner surface nor the outer surface of the window portion of the sheath.

8. The catheter according to claim 7 , wherein the reinforcement includes a reinforcement tube constituting the portion of the reinforcement that is axially movable, and further comprising a reinforcement tube steering unit operatively connected to the reinforcement tube to axially move the reinforcement tube along an axial extent of the sheath.

9. The catheter according to claim 8 , wherein the reinforcement tube steering unit includes a main body fixed to the sheath and a rotation member rotatably mounted on the main body, the rotation member being operatively linked with the reinforcement tube so that rotation of the rotatable member results in axial movement of the reinforcement tube.

10. The catheter according to claim 7 , wherein the reinforcement includes a reinforcement tube constituting the portion of the reinforcement that is axially movable, and wherein the reinforcement tube and the detection unit are axially fixed relative to one another so that the reinforcement tube is not axially movable relative to the detection unit, and a distal-most end of the reinforcement tube is positioned proximally of a distal end of the detection unit so that the distal-most end of the detection unit is distal of the distal-most end of the reinforcement tube.

11. The catheter according to claim 7 , further comprising:

a drive shaft positioned inside the sheath and fixed to the detection unit to transmit a mechanical driving force to the detection unit by way of the drive shaft;

a hub for axially moving the drive shaft in an axial direction of the sheath; and

wherein the portion of the reinforcement is interlinked to the hub and is axially movable together with the hub and the drive shaft.

12. The catheter according to claim 7 , wherein a distal end portion of the sheath includes a housing unit configured to accommodate the detection unit.

13. The catheter according to claim 7 , wherein the sheath includes a sheath distal member provided with a through hole configured to receive a guide wire to guide movement of the catheter toward a target site in the body lumen.

14. A method comprising:

inserting a catheter in a body lumen of a living body, the catheter comprising a sheath provided with a window portion permeable to inspection waves, and a detection unit axially movably positioned inside the sheath, the window portion possessing an axial extent extending from a distal-most end of the window portion to a proximal-most end of the window portion;

moving the catheter until a distal end portion of the catheter is positioned adjacent a target lesion in the body lumen, the moving of the catheter being performed while an entirety of the axial extent of the window portion of the sheath is reinforced by reinforcement that axially overlaps the entirety of the axial extent of the window portion of the sheath;

axially moving at least a part of the reinforcement in a proximal direction relative to the sheath to uncover at least a proximal portion of the window portion of the sheath;

directing inspection waves at the body lumen; and

receiving at the detection unit reflected inspection waves which have reflected off the body lumen and passed through the window portion of the sheath.

15. The method according to claim 14 , wherein the sheath includes a sheath distal member provided with a through hole, and wherein the catheter is moved to a position adjacent the target lesion in the body lumen by moving the catheter along a guide wire passing though the through hole in the sheath distal member.

16. The method according to claim 14 , wherein the axially moving of the part of the reinforcement in the proximal direction to uncover the proximal portion of the window portion of the sheath comprises rotating an operation dial to axially move the part of the reinforcement.

17. The method according to claim 14 , wherein the axially moving of the part of the reinforcement in the proximal direction to uncover the proximal portion of the window portion of the sheath comprises rotating an operation dial connected to a rotation member which is in contact with an outer surface of the part of the reinforcement to rotate the rotation member and axially move the part of the reinforcement tube.

18. The catheter according to claim 1 , wherein the reinforcement includes a reinforcement portion covering a distal portion of the window portion and accommodating the detection unit when the detection unit is positioned at a distal-most position, the reinforcement also including an axially movable reinforcement tube constituting the portion of the reinforcement that is axially movable, the reinforcement portion and the reinforcement tube each possessing a distal end, the distal end of the reinforcement portion being located distal of the distal end of the reinforcement tube.

19. The catheter according to claim 7 , wherein the reinforcement includes a reinforcement portion covering a distal portion of the window portion and accommodating the detection unit when the detection unit is positioned at a distal-most position, the reinforcement also including an axially movable reinforcement tube constituting the portion of the reinforcement that is axially movable, the reinforcement portion and the reinforcement tube each possessing a distal end, the distal end of the reinforcement portion being located distal of the distal end of the reinforcement tube.

20. The method according to claim 14 , wherein the axially moving of the part of the reinforcement in the proximal direction relative to the sheath includes axially moving a reinforcement tube in the proximal direction relative to the sheath, the reinforcement also comprising a reinforcement portion covering a distal portion of the window portion and accommodating the detection unit when the detection unit is positioned at a distal-most position.