Safety mechanism and methods to prevent rotating imaging device from exiting a catheter

A catheter system comprising:

• a catheter comprising a catheter body having a proximal end, a distal end, a lumen which terminates in an exit port at the distal end, and an ultrasonically recognizable pattern disposed proximally to or at the exit port;
• an elongate imaging device having a proximal end, a distal end, and an imaging element near the distal end, the imaging device being receivable in the lumen;
• and
• a controller having a motor which is adapted to rotate the imaging device, wherein the controller is adapted to stop rotation of the imaging device upon receipt of a signal from the imaging device indicating that the presence of the recognizable pattern has been detected.

A method for visualizing a body lumen, the method comprising:

• introducing a catheter into a body lumen, the catheter comprising a catheter body having a proximal end, a distal end, a lumen which terminates in an exit port at the distal end, and an ultrasonically recognizable pattern disposed proximally to or at the exit port;
• introducing an elongate imaging device into the lumen, the imaging device having an imaging element near a distal end;
• rotating the imaging device and actuating the imaging element to produce an image of the body lumen;
• and
• stopping rotation of the imaging device when an image of the recognizable pattern is detected to prevent advancement of the rotating imaging device through the exit port and into the body lumen.

A method for preventing the advancement of a rotating imaging device beyond an exit port of a catheter, the method comprising:

• rotating an imaging device having an imaging element within a lumen of a catheter, the imaging device having an ultrasonically recognizable pattern near or at a distal end;
• moving the imaging device within the lumen;
• and
• stopping rotation of the imaging device when a signal from the imaging device indicates that the imaging device has reached the ultrasonically recognizable pattern.