Device and Method for Intravascular Imaging and Sensing

Abstract

An intravascular sensor device can be used to guide treatment of a diseased blood vessel in the body of a patient. In some examples, the intravascular sensor device includes a pressure sensor and an ultrasound transducer. The intravascular sensor device is used to measure a pressure within the diseased blood vessel and acquire an ultrasound image of the diseased blood vessel. The pressure may be measured during hyperemic blood flow that is caused by a pharmacologic vasodilator drug. The measured pressure can be used to calculate a fractional flow reserve value. The ultrasound image can be used to determine a physical dimension of the blood vessel, such as cross-sectional area. The fractional flow reserve value and physical dimensions of the blood vessel can be used to optimize patient treatment.

What is claimed is: 
     
         1 . A sensing catheter deployed in a percutaneous coronary intervention configuration in a blood vessel, comprising:
 a distal-end first portion having a first cross-sectional area, comprising:
 an ultrasound transducer array; 
 a pressure sensor; 
 a guide wire lumen; and 
 a guide wire within the guide wire lumen, 
   
       the first portion being deployed within a first length of the blood vessel; and
 a second portion of a second reduced cross-sectional area, the second portion being deployed within a second length of blood vessel, the reduced cross-sectional area reducing an influence of the catheter on a pressure reading of the pressure sensor and enabling a more indicative pressure reading of the pressure sensor than if the diameter of the second section were not reduced. 
 
     
     
         2 . A sensing catheter for insertion into a blood vessel, comprising:
 a distal-end first portion having a first cross-sectional area, comprising:
 an ultrasound transducer array; 
 a pressure sensor; and 
 a lumen for receiving a guide wire; and 
   a second portion of a second reduced cross-sectional area;   wherein the reduced diameter of the second portion reduces an influence of the catheter on a pressure reading of the pressure sensor and enables a more indicative pressure reading of the pressure sensor than if the diameter of the second portion were not reduced.   
     
     
         3 . The sensing catheter of  claim 2 , wherein the guide wire lumen is discontinued along a length of the second portion. 
     
     
         4 . The sensing catheter of  claim 2 , wherein the pressure sensor is a piezoresistive pressure sensor. 
     
     
         5 . The sensing catheter of  claim 2 , where the pressure sensor is an optical pressure sensor. 
     
     
         6 . The sensing catheter of  claim 2 , wherein the ultrasound transducer array is configured to operate at least one frequency between 20 MHz and 80 MHz. 
     
     
         7 . The sensing catheter of  claim 2 , wherein the ultrasound transducer array comprises at least one capacitive micromachined ultrasound transducer. 
     
     
         8 . The sensing catheter of  claim 2 , wherein the ultrasound transducer array comprises at least one piezoelectric micromachined ultrasound transducer. 
     
     
         9 . The sensing catheter of  claim 2 , wherein the pressure sensor and the ultrasound transducer array are fabricated on the same substrate. 
     
     
         10 . The sensing catheter of  claim 9 , wherein the substrate comprises complementary metal-oxide-semiconductor circuitry. 
     
     
         11 . The sensing catheter of  claim 2  wherein the second portion comprises a first section that is substantially tubular and has an outer diameter of 0.03 inches or smaller. 
     
     
         12 . The sensing catheter of  claim 11 , wherein the second portion includes a first end and a second end wherein the flexibility of the first section varies between the first end and the second end. 
     
     
         13 . The sensing catheter of  claim 11 , wherein the second portion comprises a second section that is substantially tubular and has an outer diameter between 0.016 inches and 0.064 inches, inclusive. 
     
     
         14 . The sensing catheter of  claim 2 , comprising a communication assembly configured to receive signals from the pressure sensor, send signals to the ultrasound transducer assembly, and receive signals from the ultrasound transducer assembly. 
     
     
         15 . The sensing catheter of  claim 14 , wherein the communication assembly includes a flexible circuit assembly. 
     
     
         16 . The sensing catheter of  claim 14 , wherein the communication assembly includes at least one cable. 
     
     
         17 . The sensing catheter of  claim 14 , wherein the communication assembly includes an optical fiber. 
     
     
         18 . An intravascular device comprising an elongated body including a first portion having a first cross-sectional area and a lumen configured to receive a guide wire; a second portion bonded to the first portion having a second cross-sectional area less than the first cross-sectional area; a first sensor adapted to measure pressure; a second sensor configured to transmit and receive ultrasound pressure; and a communication assembly adapted to receive signals from the first sensor, send signals to the second sensor, and receive signals from the second sensor.