Asymmetry is provided for the pushing pulse in acoustic radiation force impulse (ARFI) imaging. MI is based on the negative pressure. By increasing the positive pressure more than the negative pressure, the magnitude of displacement may be increased without exceeding the MI limit. Similarly, negative voltages depole while positive do not, so using an ARFI or pushing pulse with asymmetric positive-to-negative peak pressures or voltages allows for generation of greater magnitude of displacement without harm to the transducer.

Changes in tissue stiffness have long been associated with disease. Systems and methods for determining the stiffness of tissues using ultrasonography may include a device for inducing a propagating shear wave in tissue and tracking the speed of propagation, which is directly related to tissue stiffness and density. The speed of a propagating shear wave may be detected by imaging a tissue at a high frame rate and detecting the propagating wave as a perturbance in successive image frames relative to a baseline image of the tissue in an undisturbed state. In some embodiments, sufficiently high frame rates may be achieved by using a ping-based ultrasound imaging technique in which unfocused omni-directional pings are transmitted (in an imaging plane or in a hemisphere) into a region of interest. Receiving echoes of the omnidirectional pings with multiple receive apertures allows for substantially improved lateral resolution.

Provided is a method of controlling a ultrasound diagnostic apparatus, in which a plurality of tracking pulses are transmitted at preset intervals to observe a shear wave induced in a region of interest (ROI) of an object, multi-reception scan lines corresponding to each of the tracking pulses are set, and signal processing is selectively performed on the multi-reception scan lines.

A method for imaging an object by ultrasound elastography through continuous vibration of the ultrasound transducer is taught. An actuator directly in contact with the ultrasound transducer continuously vibrates the transducer in an axial direction, inducing shear waves in the tissue and allowing for real-time shear wave imaging. Axial motion of the transducer contaminates the shear wave images of the tissue, and must be suppressed. Therefore, several methods for correcting for shear wave artifact caused by the motion of the transducer are additionally taught.

A method for performing shear wave elastography imaging of an observation field in a medium, the method including shear wave imaging steps to acquire sets of shear wave propagation parameters, the method further including a reliability indicator determining step during which a reliability indicator of the shear wave elastography imaging of the observation field is determined.

A method for obtaining an elastic feature of an object includes inducing a first shear wave in the object by transmitting a first push ultrasound signal which is generated by a probe of an ultrasound apparatus and a first grating lobe signal which relates to the first push ultrasound signal toward the object, transmitting a tracking ultrasound signal to an area of the object where the first shear wave has propagated, receiving, from the object, a reflection signal which relates to the tracking ultrasound signal, measuring a first shear wave parameter which indicates a shear wave characteristic of the first shear wave based on the reflection signal, and obtaining an elastic feature of the object by using the first shear wave parameter.

Various approaches for calibrating the geometry of an ultrasound transducer having multiple transducer elements include providing an acoustic reflector spanning an area traversing by multiple beam paths of ultrasound waves transmitted from all (or at least some) transducer elements to a focal zone; causing the transducer elements to transmit the ultrasound waves to the focal zone; measuring reflections of the ultrasound waves off the acoustic reflector; and based at least in part on the measured reflections, determining optimal geometric parameters associated with the transducer elements.

Fat fraction is estimated from shear wave propagation. Acoustic radiation force is used to generate a shear wave in tissue of interest. The attenuation, center frequency, bandwidth or other non-velocity characteristic of the shear wave is calculated and used to estimate the fat fraction.

Various approaches for calibrating the geometry of an ultrasound transducer having multiple transducer elements include providing an acoustic reflector spanning an area traversing by multiple beam paths of ultrasound waves transmitted from all (or at least some) transducer elements to a focal zone; causing the transducer elements to transmit the ultrasound waves to the focal zone; measuring reflections of the ultrasound waves off the acoustic reflector; and based at least in part on the measured reflections, determining optimal geometric parameters associated with the transducer elements.

The present invention proposes an ultrasound imaging system and method for measuring a property of a region of interest in a subject by using shear wave, wherein an ultrasound probe is configured to sequentially transmit, to each of a plurality of focal spots (320, 322, 324) in the region of interest, a push pulse (310, 312, 314) for generating a shear wave (330, 332, 334), each of the plurality of focal spots having a mutually different depth value (z1, z2, z3), and to receive ultrasound echo signals adjacent (350, 352, 354) to each of the plurality of focal spots; a shear wave detector is configured to derive, for each of the plurality of focal spots, a first parameter indicating a property of the generated shear wave, based on the received ultrasound echo signals; and a property estimator is configured to estimate a second parameter indicating the property of the region of interest as a function of the derived first parameters.