Abstract: An ultrasonic blood flow measuring and imaging system comprises a transmit-receive transducer for transmitting ultrasonic waves toward and into the human body and for receiving reflected echo signals which are then processed for use in a Doppler blood flow imaging and display system. Multiple ultrasonic pulse beams are transmitted into the body at each of a number of angles in an area under diagnosis. For each angle, a plurality of reflected echo signals are received during successive predetermined time intervals. Each received echo signal has a stationary component reflected from essentially stationary tissue and a Doppler component reflected from areas where movement is sensed, such as blood flow. The reflected echo signals are processed in an MTI filter subtracting a stationary component from the received echo signals to thereby extract a Doppler signal representative of a Doppler component of the received echo signals.

Abstract: An ultrasonic blood flow measuring and imaging system comprises a transmit-receive transducer for transmitting ultrasonic pulses toward and into the human body and for receiving reflected echo signals which are then processed for use in a Doppler blood flow imaging and display system. Multiple ultrasonic pulses are transmitted into the body at each of a number for angles in an area under diagnosis. For each angle, a plurality of reflected echo signals are received during successive predetermined time intervals. Each received echo signal has a tissue motion Doppler component representative of reflection from moving tissue and a blood flow Doppler component representative of relfection from both moving tissue and flowing blood. The reflected echo signals are processed in a system which includes tissue velocity determining elements for estimating the velocity of the tissue motion, and tissue velocity canceller elements for removing a tissue velocity component from the received echo signals.

Abstract: A system for improving the flow estimation sensitivity of an ultrasonic Doppler flow imaging system includes an ultrasonic wave tranmitter and receiver for sequentially transmitting ultrasonic waves toward and into a living body and for receiving the reflected Doppler-shifted echo signals. A series of echo signals received from each of a number of points within the body are processed in a velocity estimator, using maximum entropy techniques, to produce an output signal representative of an estimated velocity of the flow at each of said points within the body. The processing means detects the series of echo signals for each point and calculates an average power spectrum based on the amplitude-versus-frequency distribution of the series of received echo signals. The power spectrum is calculated by fitting a first order polynomial to the series of echo signals, although higher order polynomials can be used.