Device, system and method for flow imaging in the body using a swept transducer

An intravascular ultrasound (IVUS) imaging system, the system comprising:

• an ultrasound emitter and receiver movably disposed within an IVUS imaging device comprising an elongate member sized and shaped to be positioned in a lumen of a blood vessel of a patient;
• an actuator coupled to the emitter, the actuator moving the emitter through a path comprising at least a portion of an arc within the blood vessel of the patient, wherein the actuator is configured to oscillate the emitter about a pivot pin such that the emitter sweeps forward and returns along the at least a portion of an arc within a plane perpendicular to an axis of the pivot pin;
• and
• a control system in communication with the actuator such that the control system controls movement of the emitter through the path at a desired angular velocity profile, wherein the desired angular velocity profile comprises an angular velocity of the emitter that is non-linear over time so that the emitter moves at a first velocity during the forward sweep of the arc and at a second velocity that is different than the first velocity during the return sweep of the arc, wherein the first velocity is associated with F-mode ultrasonic imaging and the second velocity is associated with B-mode ultrasonic imaging, wherein the control system includes:
• an acquisition controller controlling the emission of pulses from the emitter including a plurality of F-mode pulses emitted during the forward sweep at the first velocity and a plurality of B-mode pulses emitted during the return sweep at the second velocity, and receiving, from the receiver, echo velocity acoustic samples from the F-mode pulses and echo amplitude acoustic samples from the B-mode pulses associated with the pulses emitted along the forward and return sweeps of the emitter, respectively;
• an intensity module processing the echo amplitude acoustic samples to generate echo amplitude data, wherein the intensity module compares the echo amplitude acoustic samples to a variable echo amplitude acoustic threshold, wherein the variable echo amplitude acoustic threshold is adjusted based upon the angular velocity of the emitter;
• a flow module processing the echo velocity acoustic samples to generate echo velocity data;
• and
• an image compositor generating a hybrid IVUS image representing both of the echo amplitude data e-and the echo velocity data in the same image, wherein the IVUS image represents the echo amplitude data in grayscale and the echo velocity data in color;
• wherein the acquisition controller further controls the ultrasound emitter and receiver to obtain the echo velocity data associated with ultrasound reflections of the first pulses from a first depth within the blood vessel including the lumen and to obtain the echo amplitude data associated with ultrasound reflections of the second pulses from a second depth within the blood vessel including a lumen boundary, the first and second depths located along a ray of the first and second pulses respectively from the emitter positioned within the lumen of the blood vessel, wherein the second depth is greater than the first depth.