The present disclosure related generally to ultrasound imaging, such as intravascular ultrasound imaging. For example, some embodiments of the present disclosure provide an ultrasound imaging system with improved acoustic impedance matching between an ultrasonic transducer and a vessel of interest. For example, in some implementations, an ultrasound imaging device includes a flexible elongate member and an ultrasound scanner assembly disposed at a distal portion of the flexible elongate member. The ultrasound scanner assembly includes a plurality of ultrasound transducers arranged circumferentially, and an impedance matching structure is coupled to the plurality of ultrasound transducers. In some such embodiments, the impedance matching structure is disposed radially outward from the plurality of ultrasound transducers, and in some embodiments, the impedance matching structure is disposed radially inward from the plurality of ultrasound transducers.
