Methods and systems for broadband intravascular ultrasound imaging

A method for a broadband intravascular ultrasound imaging system comprising a processing subsystem operatively coupled to a broadband ultrasound transducer, the method comprising:

• convolving one or more base ultrasound pulses corresponding to a particular frequency with a desired code to generate an extended excitation wave for driving the broadband transducer at a plurality of different frequencies;
• transmitting the extended excitation wave to a broadband ultrasound transducer to be transmitted towards the target, the broadband ultrasound transducer comprising a micromachined piezoelectric composite body having a front side and a back side opposite to the front side, wherein the micromachined piezoelectric composite body is configured to convert electrical signals into ultrasound waves to be transmitted from the front side toward the target, and wherein the micromachined piezoelectric composite body is configured to convert the received echo signals into electrical signals, the micromachined piezoelectric composite body including a plurality of piezoelectric posts separated from each other by a plurality of filler members;
• and a dematching layer connected to the back side of the micromachined piezoelectric composite body and having higher acoustic impedance than an acoustic impedance of the micromachined piezoelectric composite body, the dematching layer not including the plurality of piezoelectric posts and the plurality of filler members;
• receiving echo signals reflected back from the target in response to the extended excitation wave;
• de-convolving the received echo signals to recover an original resolution of the broadband ultrasound transducer at the plurality of different frequencies;
• and
• generating a plurality of ultrasound images of the target corresponding to each of the plurality of different frequencies based on the de-convolved echo signals.

A non-transitory computer readable medium that stores instructions executable by a broadband intravascular ultrasonic imaging system comprising a broadband ultrasound transducer coupled to one or more processors to perform a method for ultrasound imaging, the non-transitory computer readable medium configured to:

• convolve one or more base ultrasound pulses corresponding to a particular frequency with a desired code to generate an extended excitation wave for driving the broadband transducer at a plurality of different frequencies;
• transmit the extended excitation wave to a broadband ultrasound transducer to be transmitted towards the target, the broadband ultrasonic transducer comprising a micromachined piezoelectric composite body having a front side and a back side opposite to the front side, wherein the micromachined piezoelectric composite body is configured to convert electrical signals into ultrasound waves to be transmitted from the front side toward the target, and wherein the micromachined piezoelectric composite body is configured to convert the received echo signals into electrical signals, the micromachined piezoelectric composite body including a plurality of piezoelectric posts separated from each other by a plurality of filler members;
• and a dematching layer connected to the back side of the micromachined piezoelectric composite body and having higher acoustic impedance than an acoustic impedance of the micromachined piezoelectric composite body, the dematching layer not including the plurality of piezoelectric posts and the plurality of filler members;
• receive echo signals reflected back from the target in response to the extended excitation wave;
• de-convolve the received echo signals to recover an original resolution of the broadband ultrasound transducer at the plurality of different frequencies;
• and
• generate a plurality of ultrasound images of the target corresponding to each of the plurality of different frequencies based on the de-convolved echo signals.