Multimodal Catheter System and Method for Intravascular Analysis

Abstract

Methods, apparatus, and systems for intravascular analysis combine at least three analytical modalities. In one implementation, intravascular ultrasound, optical coherence tomography, and near infrared spectroscopy are combined to enable detection of multiple, different abnormalities in the arterial morphology during a single intravascular procedure.

1 . An intravascular catheter system comprising:
 at least one optical fiber configured to transmit optical radiation between distal and proximal ends thereof, wherein said distal end of said optical fiber is in optical communication with an arterial wall;   at least one source of optical radiation optically coupled to a portion of said optical fiber and configured to generate optical radiation to be transmitted by said optical fiber to the arterial wall;   an interferometer optically coupled to a portion of said optical fiber and configured to receive optical radiation transmitted by said optical fiber from the arterial wall and to provide an interference signal for sub-surface imaging of the arterial wall;   an optical processing module optically coupled to a portion of said optical fiber and configured to receive optical radiation transmitted by said optical fiber from the arterial wall and to provide spectroscopic information about the arterial wall from detected intensity of the light collected from the arterial wall;   an ultrasound transducer configured to transmit ultrasound energy toward the arterial wall, receive ultrasound energy reflected from the arterial wall, and convert the received ultrasound energy to an electric signal; and   an ultrasonic subsystem in communication with said ultrasound transducer and configured to generate an ultrasonic image from the electric signal.   
     
     
         2 . The intravascular catheter system of  claim 1 , wherein said at least one optical fiber comprises a delivery fiber and a collection fiber and wherein said at least one source is optically coupled with a portion of said delivery fiber, said interferometer is optically coupled to a portion of said delivery fiber and configured to receive optical radiation transmitted by said delivery fiber from the arterial wall, and said optical processing module is optically coupled to a portion of said collection fiber and configured to receive optical radiation transmitted by said collection fiber from the arterial wall. 
     
     
         3 . The intravascular catheter system of  claim 2 , wherein said delivery fiber is a single mode optical fiber configured to propagate only a single spatial mode and said collection fiber comprises a multimode fiber. 
     
     
         4 . The intravascular catheter system of  claim 1 , further comprising at least one reflector configured to redirect optical radiation from said distal end of said optical fiber toward the arterial wall and to redirect at least a portion of the optical radiation from the arterial wall toward said distal end of said fiber. 
     
     
         5 . The intravascular catheter system of  claim 1 , wherein said at least one optical radiation source comprises one or both of a tunable laser and a super luminescent light emitting diode. 
     
     
         6 . The intravascular catheter system of  claim 1 , wherein said ultrasound transducer is configured to employ time multiplexing to both transmit ultrasound energy toward the arterial wall and receive ultrasound energy from the arterial wall. 
     
     
         7 . The intravascular catheter system of  claim 1 , further comprising one or more wires providing an electrical connection between said ultrasound transducer and said ultrasonic subsystem. 
     
     
         8 . The intravascular catheter system of  claim 1 , further comprising an outer sheath covering at least a portion of said optical fiber. 
     
     
         9 . The intravascular catheter system of  claim 8 , further comprising a guide wire coupled to a portion of said sheath and configured to guide movement of said sheath and said optical fiber through an intravascular lumen. 
     
     
         10 . The intravascular catheter system of  claim 1 , further comprising a position detection system comprising an internal element configured to be inserted into an intravascular lumen along with said optical fiber and an external element disposed outside the intravascular lumen, wherein said internal element and said external element are configured for communication therebetween for locating a position of said internal element relative to said external element. 
     
     
         11 . The intravascular catheter system of  claim 1 , wherein said at least one optical fiber and said ultrasound transducer comprise a catheter core, and wherein said system further comprises a torque cable coupled to said catheter core and configured to transmit a rotational force to a distal portion of said catheter core. 
     
     
         12 . The intravascular catheter system of  claim 11 , further comprising a pullback and rotation unit coupled to said torque cable and configured to withdraw and rotate said optical fiber and said ultrasound transducer within an intravascular lumen. 
     
     
         13 . The intravascular catheter system of  claim 12 , wherein said pullback and rotation unit is further configured to couple optical signals from the rotating optical fiber to the non-rotating optical processing module. 
     
     
         14 . The intravascular catheter system of  claim 1 , wherein said ultrasound transducer is distally spaced from said distal end of said optical fiber.