Patent ID: 11918761
Assignee: INFRAREDX, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 11:
12. A method of imaging a vessel using an intravascular imaging catheter system, comprising:
a pullback and rotation unit for axially translating and rotating a torque cable in an elongate outer sheath of a catheter, wherein the pullback and rotation unit comprises:
a housing with a longitudinal axis;
a rotor disposed in the housing and mounted to rotate and linearly translate relative to the longitudinal axis of the housing, the rotor further being configured to be coupled with a proximal end of the torque cable;
a plurality of sensors configured on the rotor and radially spaced from an axis of rotation of the rotor and configured to provide an output indicative of an axial force exerted by the torque cable on the rotor;
wherein the output is an average of an output from each of the plurality of sensors over a period of time for at least one full rotation of an imaging tip located at a distal end of the torque cable;
a controller configured to, when the output exceeds a predetermined threshold, cause the rotor to automatically perform a remedial action to relieve at least a portion of the axial force, wherein the controller is configured to cause the rotor, when performing the remedial action, to retract proximally a predetermined distance; and
wherein the predetermined threshold is set below a level at which damage to the outer sheath will occur due to a distal end of the torque cable being unable to traverse a portion of the outer sheath; and

an imaging catheter including an elongate outer sheath having a proximal end coupled with the housing, the torque cable being disposed in the outer sheath and having a proximal end coupled with the rotor, and an imaging tip located at a distal end of the torque cable and including at least one imaging component selected from the group consisting of an optical element and an ultrasonic transducer;
the method comprising: coupling the proximal end of the elongate outer sheath with the housing of the pullback and rotation unit;
coupling the proximal end of the torque cable with the rotor disposed within the housing of the pullback and rotation unit;
inserting the catheter into the vessel;
linearly translating the imaging tip distally relative to the outer sheath by linearly translating the rotor distally in the housing of the pullback and rotation unit;
receiving an output from at least one sensor indicative of an axial force applied to the rotor by the torque cable; and
based on the output from the at least one sensor exceeding a predetermined threshold, causing the rotor to automatically perform a remedial action to relieve at least a portion of the axial force wherein causing the rotor, when performing the remedial action, to retract proximally a predetermined distance;
wherein the predetermined threshold is set below a level at which damage to the outer sheath will occur due to the distal end of the torque cable being unable to traverse a portion of the outer sheath.