Ultrasonic Doppler imager having an adaptive tissue rejection filter with enhanced tissue motion sensitivity

An ultrasonic Doppler diagnostic flow imaging and measuring system, comprising:

• ultrasonic wave transmitting and receiving means for developing for each beamline of a scan into a body a plurality of three or more acoustic lines of signal samples in response to the receipt of reflections from ultrasonic pulses transmitted into the body during the scan;
• a corner turning memory operative during a write mode for receiving and storing said acoustic lines of signal samples as a plurality of sequential digital samples for each acoustic line, and subsequently supplying said samples during a read-out mode;
• flow processor responsive to said acoustic lines of signal samples as provided by said corner turning memory during said read-out mode for detecting a Doppler shift in said samples and developing velocity estimate signals therefrom;
• a tissue processor, responsive to velocity estimate signals for developing therefrom a control signal representative of the movement of tissue;
• and
• a tissue rejection filter arrangement having a signal input responsive to said acoustic line samples, and a control input responsive to said control signal representative of tissue movement, for causing said filter arrangement to suppress tissue movement signals from said acoustic line samples applied to said signal input of the tissue rejection filter arrangement, wherein during development of velocity estimate signals for use by said tissue processor, read-out of said corner turning memory is controlled so as to periodically skip one or more of said acoustic lines of samples as said lines are provided from a first one of said lines to a last one of said lines, to said flow processor.

A method for processing scanning beamlines of received ultrasound signals in an ultrasound flow imaging system so as to develop flow signals in which contributions to said flow signals of ultrasonic reflections from non-flow movement are suppressed, said method comprising the steps of:

• transmitting and receiving ultrasonic waves for developing a plurality of beamlines which scan an area, each beamline including a plurality of three or more acoustic lines of signal samples in response to the receipt of reflections from ultrasonic waves transmitted into the area during the scan;
• storing in a memory said acoustic lines of signal samples as a plurality of sequential digital samples for each acoustic line, and subsequently supplying from said memory said samples during a read-out mode;
• flow processing said acoustic lines of signal samples as provided by said corner turning memory during said read-out mode for detecting a Doppler shift in said samples and developing velocity estimate signals therefrom;
• tissue processing said velocity estimate signals for developing therefrom a control signal representative of the movement of tissue;
• tissue rejection filtering said acoustic line samples in response to said control signal, for causing said filter arrangement to suppress tissue movement signals from said acoustic line samples applied to said signal input of the tissue rejection filter arrangement;
• and controlling said memory during supply of acoustic line signal samples used for flow processing, so as to periodically skip one or more of said acoustic lines of samples as said lines are provided from a first one of said lines to a last one of said lines, for flow processing.