Sensor interface device providing digital processing of intravascular flow and pressure data

Abstract

Embodiments of the present disclosure are configured to assess the severity of a blockage in a vessel and, in particular, a stenosis in a blood vessel. In some particular embodiments, the devices, systems, and methods of the present disclosure are configured to assess the severity of a stenosis in the coronary arteries by monitoring fluid flow. In some embodiments, the devices, systems, and methods of the present disclosure receive analog sensor data that includes fluid flow data and digitizes the analog sensor data according to a quadrature sampling rate. A weighted accumulator performs a baseband conversion on the digitized sensor data and may perform other signal processing steps. The processed data is then provided for use in any one of a number of diagnostic assessments.

What is claimed is: 
     
         1 . A medical diagnostic system comprising:
 a patient interface module operable to process analog flow sensor data received from an intravascular device, wherein the patient interface module includes:
 an analog-to-digital converter operable to sample the analog flow sensor data according to a quadrature sampling rate to produce digital flow sensor data; 
 a signal processing resource operable to perform a baseband conversion on the digital flow sensor data to produce baseband flow sensor data; and 
 an interface subunit operable to output the baseband flow sensor data. 
   
     
     
         2 . The medical diagnostic system of  claim 1 , wherein the analog flow sensor data includes a measurement of fluid flow velocity within a vessel. 
     
     
         3 . The medical diagnostic system of  claim 1 , wherein the quadrature sampling rate is defined by the equation:
   quadrature sampling rate=4/(2 N +1)×a nominal center frequency
   where N is an integer greater than or equal to zero.   
     
     
         4 . The medical diagnostic system of  claim 3 , wherein a carrier frequency is chosen to be equal to the nominal center frequency of an ultrasound transducer used to obtain the analog flow sensor data. 
     
     
         5 . The medical diagnostic system of  claim 3 , wherein N is selected such that the quadrature sampling rate is at least a Nyquist rate of the analog flow sensor data. 
     
     
         6 . The medical diagnostic system of  claim 1 , wherein the signal processing resource includes a weighted accumulator operable to perform the baseband conversion on the digital flow sensor data. 
     
     
         7 . The medical diagnostic system of  claim 6 , wherein the weighted accumulator is further operable to perform:
 in-phase signal mixing on the digital flow sensor data to produce an in-phase component;   quadrature signal mixing on the digital flow sensor data to produce a quadrature component; and   interpolation and low-pass filtering on the in-phase component and the quadrature component.   
     
     
         8 . The medical diagnostic system of  claim 6 , wherein the weighted accumulator includes an in-phase weighted accumulator and a quadrature accumulator. 
     
     
         9 . The medical diagnostic system of  claim 1  further comprising the intravascular device including a fluid flow sensor disposed at a distal end of the intravascular device, wherein the fluid flow sensor is operable to provide the analog flow sensor data to the patient interface module. 
     
     
         10 . The medical diagnostic system of  claim 1  further comprising a processing system operable to obtain a measurement of fluid flow volume based on the baseband flow sensor data and to display the measurement of fluid flow volume on a user display. 
     
     
         11 . The medical diagnostic system of  claim 1  further comprising:
 a signal separator operable to separate the analog flow sensor data from other received analog sensor data. 
 
     
     
         12 . A diagnostic method comprising:
 receiving analog sensor data including a measurement of fluid flow;   digitizing the analog sensor data to obtain digital sensor data using a quadrature sampling rate corresponding to a center frequency of an ultrasound transducer used in obtaining the analog sensor data;   performing a baseband conversion of the digital sensor data using a computing system to obtain digital baseband sensor data; and   outputting a representation of a measurement of fluid flow based on the digital baseband sensor data to a display for use in a diagnostic assessment.   
     
     
         13 . The method of  claim 12 , wherein the quadrature sampling rate is defined by the equation:
   quadrature sampling rate=4/(2 N +1)×the center frequency
   where N is an integer greater than or equal to zero.   
     
     
         14 . The method of  claim 12 , wherein the quadrature sampling rate is equal to four times the center frequency of the ultrasound transducer. 
     
     
         15 . The method of  claim 12 , wherein the performing of the baseband conversion includes supplying first and second sets of coefficients to at least one weighted accumulator, wherein the first and second sets of coefficients are selected to:
 mix the digital sensor data with a signal cos (2πf c t), where f c  is substantially equal to the center frequency in order to obtain an in-phase component;   mix the digital sensor data with a signal sin (2πf c t), where f c  is substantially equal to the center frequency in order to obtain a quadrature component; and   low-pass filter the in-phase component and the quadrature component.   
     
     
         16 . The method of  claim 15 , wherein the first and second sets of coefficients are further selected to perform at least one of: a sample-and-hold process and clutter filtering.