Samuel H. Maslak

Contrast agent imaging with destruction pulses in diagnostic medical ultrasound

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.

Medical ultrasonic imaging system with three-state ultrasonic pulse and improved pulse generator

A three-state, pulse width modulated, bipolar waveform is constructed by summing a first component with an inverted, time-shifted version of the first component. By properly selecting the time interval for the time shift of the second component, frequency filtering benefits can be obtained. The three-state waveform is generated by a switched voltage source that provides a low, constant source impedance for all three voltage states.