Scanner independent tracking of interventional instruments

Abstract

A system for tracking an instrument with ultrasound includes a probe ( 122 ) for transmitting and receiving ultrasonic energy and a transducer ( 130 ) associated with the probe and configured to move with the probe during use. A medical instrument ( 102 ) includes a sensor ( 120 ) configured to respond to the ultrasonic energy received from the probe. A control module ( 124 ) is stored in memory and configured to interpret the ultrasonic energy received from the probe and the sensor to determine a three dimensional location of the medical instrument and to inject a signal to the probe from the transducer to highlight a position of the sensor in an image.

1 . A system for tracking an instrument within a body, the system comprising:
 an acoustic transducer configured to be removably attached to an ultrasonic probe, the acoustic transducer configured to (i) sense ultrasound imaging signals emitted from the attached ultrasonic probe into the body and (ii) generate a first control signal indicating a time when an ultrasound imaging signal of the sensed ultrasound imaging signals is fired from the ultrasonic probe; and   a controller operatively connected to the ultrasonic probe with the attached acoustic transducer, the controller configured to:
 receive, from the acoustic transducer, the first control signal indicating the time when the ultrasound imaging signal is fired from the ultrasonic probe, 
 receive, from an acoustic sensor attached to the instrument, a second control signal indicating a time when the ultrasound imaging signal arrived at an acoustic sensor, and 
 determine a location of the instrument based on the received first control signal from the acoustic transducer and the received second control signal from the acoustic sensor. 
   
     
     
         2 . The system as recited in  claim 1 , wherein the acoustic transducer is further configured to inject an acoustic signal into the ultrasonic probe, wherein the injected acoustic signal simulates an echo back from the acoustic sensor. 
     
     
         3 . The system as recited in  claim 1 , wherein the injected acoustic signal is injected as a blinking signal. 
     
     
         4 . The system as recited in  claim 2 , wherein the acoustic transducer is further configured to inject the acoustic signal in frames at t 0 +nT+t d , where t 0  is a temporal maximum of the ultrasound imaging signals received by the acoustic sensor, t d  is a delay, corresponding to an ultrasound time of flight from the ultrasonic probe to the acoustic sensor, inserted to simulate an echo back from the acoustic sensor to the ultrasonic probe, and T is a frame rate and n is an integer. 
     
     
         5 . The system as recited in  claim 2 , wherein the controller is configured to control the acoustic signal to inject the acoustic signal into the ultrasonic probe. 
     
     
         6 . The system as recited in  claim 2 , further comprising a display configured to display images from the ultrasonic probe with the injected acoustic signal highlighted in the images. 
     
     
         7 . The system as recited in  claim 1 , wherein the acoustic transducer is configured to be removably attached directly to the ultrasonic probe via a coupling medium. 
     
     
         8 . The system as recited in  claim 1 , wherein the acoustic transducer is mounted, via a coupling medium, on a sheath that is configured to be removably attached to the ultrasonic probe. 
     
     
         9 . The system as recited in  claim 1 , wherein the acoustic transducer is coupled to the ultrasonic probe via a coupling medium in a form of glue that temporarily binds the acoustic transducer directly to the ultrasonic probe or to a sheath covering the ultrasonic probe. 
     
     
         10 . The system as recited in  claim 1 , wherein the acoustic transducer comprises one or more piezoelectric strips. 
     
     
         11 . The system as recited in  claim 2 , wherein the controller is further configured to (i) estimate beam positions in an image from the ultrasonic probe and (ii) overlay the location of the instrument in the image based on the beam positions. 
     
     
         12 . A method of tracking an instrument within a body, the method comprising:
 removably attaching an acoustic transducer to an ultrasound probe;   sensing, by the acoustic transducer attached to the ultrasound probe, ultrasound imaging signals emitted from the attached ultrasonic probe into the body;   generating, by the acoustic transducer attached to the ultrasound probe, a first control signal indicating a time when an ultrasound imaging signal of the sensed ultrasound imaging signals is fired from the ultrasonic probe;   receiving, by a controller from the acoustic transducer, the first control signal indicating the time when the ultrasound imaging signal is fired from the ultrasonic probe;   receiving, from an acoustic sensor attached to the instrument, a second control signal indicating a time when the ultrasound imaging signal arrived at an acoustic sensor; and   determining a location of the instrument based on the received first control signal from the acoustic transducer and the received second control signal from the acoustic sensor.   
     
     
         13 . The method as recited in  claim 11 , further comprising injecting an acoustic signal into the ultrasonic probe, wherein the injected acoustic signal simulates an echo back from the acoustic sensor. 
     
     
         14 . The method as recited in  claim 12 , wherein the injected acoustic signal is injected as a blinking signal. 
     
     
         15 . The method as recited in  claim 12 , further comprising injecting the acoustic signal in frames at t 0 +nT+t d , where t 0  is a temporal maximum of the ultrasound imaging signals received by the acoustic sensor, t d  is a delay, corresponding to an ultrasound time of flight from the ultrasonic probe to the acoustic sensor, inserted to simulate an echo back from the acoustic sensor to the ultrasonic probe, and T is a frame rate and n is an integer. 
     
     
         16 . The method as recited in  claim 11 , further comprising displaying images from the ultrasonic probe with the injected acoustic signal highlighted in the images. 
     
     
         17 . The method as recited in  claim 11 , further comprising (i) estimating beam positions in an image from the ultrasonic probe and (ii) overlaying the location of the instrument in the image based on the beam positions. 
     
     
         18 . A non-transitory computer-readable storage medium having stored a computer program comprising instructions, which, when executed by a processor, cause the processor to:
 receive, from an acoustic transducer removably attached to an ultrasonic probe, a first control signal indicating the time when an ultrasound imaging signal is fired from the ultrasonic probe, wherein the acoustic transducer generates the first control signal in response to sensing emission of the ultrasound imaging signal from the attached ultrasonic probe;   receive, from an acoustic sensor attached to an instrument within the body, a second control signal indicating a time when the ultrasound imaging signal arrived at an acoustic sensor; and   determine a location of the instrument based on the received first control signal from the acoustic transducer and the received second control signal from the acoustic sensor.   
     
     
         19 . The non-transitory computer-readable storage medium as recited in  claim 1 , wherein the instructions, when executed by the processor, further cause the processor to inject an acoustic signal into the ultrasonic probe, wherein the injected acoustic signal simulates an echo back from the acoustic sensor. 
     
     
         20 . The system as recited in  claim 2 , wherein the instructions, when executed by the processor, further cause the processor to inject the acoustic signal in frames at t 0 +nT+t d , where t 0  is a temporal maximum of the ultrasound imaging signals received by the acoustic sensor, t d  is a delay, corresponding to an ultrasound time of flight from the ultrasonic probe to the acoustic sensor, inserted to simulate an echo back from the acoustic sensor to the ultrasonic probe, and T is a frame rate and n is an integer.