An ultrasound diagnostic apparatus includes: an ultrasound probe; a transmission and reception unit that transmits an ultrasound beam from the ultrasound probe toward a subject, receives an ultrasound beam reflected from the subject, and processes a received signal output from the ultrasound probe to generate received data; a complex data generation unit that generates first complex data including amplitude information and phase information by orthogonally detecting the received data generated by the transmission and reception unit using a first center frequency and a first cutoff frequency and generates second complex data by orthogonally detecting the same data as the received data using a second cutoff frequency and a second center frequency lower than the first center frequency; a B-mode processing unit that generates a B-mode image using amplitude information of at least one of the first complex data or the second complex data; a phase difference calculation unit that calculates a first phase difference between frames using phase information of the first complex data and calculates a second phase difference between frames using phase information of the second complex data; a phase difference correction unit that corrects the first phase difference using the second phase difference; and a displacement amount calculation unit that calculates an amount of displacement of a measurement target tissue of the subject using the corrected first phase difference.

A motion processor (118) includes a motion estimator (306) that iteratively estimates a motion between a pair of consecutive frames of pre-processed echoes, wherein the motion estimator (306) generates the estimated motion based on at least on one iteration. A method includes iteratively estimating tissue motion between a pair of consecutive frames of pre-processed echoes over at least one iteration.

During transmission, a speed of ultrasound pulses gradually reduces due to their energy loss from acoustic impedance. A thickness and a density of piezoelectric (PZT) elements and a sound speed in the PZT elements decides energy of the ultrasound pulses and their detecting depth. A speed of moving objects and an angle of the moving objects with the ultrasound pulses may change a speed of reflected ultrasound pulses and affect their time of flight (TOF) and TOF shift. A method of Coding ultrasound pulses combines advantages of a continuous wave ultrasound and a pulsed wave ultrasound. So, it can be used to obtained the TOF and the TOF shift and calculate the depth and the moving speed of the detecting objects, which also avoids a problem of an aliasing for highly moving speed of the objects.

In one embodiment, a method is provided. The method includes transmitting a first set of ultrasound waves to determine whether there is fluid flow at a target area. The first set of ultrasound waves are transmitted at a first pulse repetition frequency. The method also includes determining whether there is fluid flow in a second area based on the first set of ultrasound waves. The second area is between the target area and an ultrasound probe. The method further includes transmitting a second set of ultrasound waves to detect fluid flow at the target area in response to determining that there is fluid flow in the second area between the target area and the ultrasound probe. The second set of ultrasound waves are directed towards the target area. The second set of ultrasound waves are transmitted at a second pulse repetition frequency.

In spectral Doppler imaging, a high PRF is used independent of the velocity scale. The adjustment is then of the velocity scale. By optimizing the velocity scale independent of the high PRF in an on-going or automated basis, user activation may be avoided and/or interruption to reconfigure for an altered PRF may be avoided. The acquired data may be stored, allowing for past data to be processed again when a new velocity scale or other setting is selected. The resulting spectral Doppler image may continue to display spectra over time without a gap or without premature loss of spectra due to reconfiguring.

In spectral Doppler imaging, a high PRF is used independent of the velocity scale. The adjustment is then of the velocity scale. By optimizing the velocity scale independent of the high PRF in an on-going or automated basis, user activation may be avoided and/or interruption to reconfigure for an altered PRF may be avoided. The acquired data may be stored, allowing for past data to be processed again when a new velocity scale or other setting is selected. The resulting spectral Doppler image may continue to display spectra over time without a gap or without premature loss of spectra due to reconfiguring.

An ultrasound diagnostic apparatus repeats ultrasonic wave transmissions with different transmission angles in units of packets. The apparatus receives reception signals. The apparatus performs beamforming on the reception signals. The apparatus performs MTI filtering on initial images for each group of the same transmission angle. The apparatus performs principal component analysis on the MTI images for each of the packets having the same set of transmission angles. The apparatus performs coherent addition on the principal component images for each of the packets to generate coherent addition images.