An acoustically-active catheter (AAC) for use with an ultrasound imaging system and a method for tracking the AAC with respect to anatomic target chosen within a body using the interference ultrasonography. A tip of the AAC is equipped with a crystal transmitting an acoustic wave with parameters similar to those of an acoustic wave generated by a transducer of the imaging system so as to produce acoustic interference the strength of which depends on a position of the AAC tip with respect to at least one Doppler scan plane, formed by the imaging transducer, and a distance from a pulsed-wave Doppler sample that is overlapped with the anatomic target. The ultrasound imaging system detects the interference signal and produces a visual and/or audible interference output that indicates the strength of the acoustic interference. Based on the intensity of the interference output, the user can navigate the AAC tip towards the anatomic target. An anatomic target can be chosen within a cardiovascular system.