The invention is directed to improvements in diagnostic medical ultrasound contrast agent imaging. In a preferred embodiment, high pulse repetition frequency (HPRF) destruction pulses are fired at a rate higher than necessary for receiving returning echoes. Pulse parameters can also be changed between the plurality of contrast agent-destroying pulses. Other preferred embodiments of the invention are directed to simultaneous transmission of multiple beams of destruction pulses. Destruction frames that consist of a plurality of destruction pulses can be triggered and swept over the entire region of tissue being imaged and at a variety of focal depths from the transmitter. The destruction frames are fired at some time triggered from a timer or some fixed part of a physiological signal, such as an ECG signal. Other preferred embodiments of the invention are directed to continuous low power imaging pulses alternating with destruction pulses triggered at a fixed point of a physiological signal, and a comparison of the received signals from imaging pulses fired before and after the destruction pulses. Alternatively, destruction pulses are triggered at a fixed point on a physiological signal different from the fixed point of a physiological signal used to trigger imaging pulses. In another embodiment, triggered destruction frames are used to enable a comparison of imaging frames in order to determine physiological functions, such as perfusion of blood in cardiac tissue. Finally, in another embodiment, destruction pulses are combined with subharmonic imaging.