An ultrasonic diagnostic imaging system produces an image of shear wave velocities by transmitting push pulses to generate shear waves. A plurality of tracking lines are transmitted and echoes received by a focusing beamformer adjacent to the location of the push pulses. The tracking lines are sampled in a time-interleaved manner. The echo data acquired along each tracking line is processed to determine the time of peak tissue displacement caused by the shear waves at points along the tracking line, and the times of peaks at adjacent tracking lines compared to compute a local shear wave velocity. The resultant map of shear wave velocity values is color-coded and displayed over an anatomical image of the region of interest.

An ultrasonic diagnostic imaging for analyzing shear wave characteristics utilizes a background motion compensation subsystem which acts as a spatial filter of pulse-to-pulse autocorrelation phases over the ROI of tracking pulse vectors to compensate for background motion. The subsystem is configured to compute the sum of all lag-1 autocorrelations of tracking line ensemble data over the tracking ROI, for each PRI. The inventive technique does not significantly reduce sensitivity to shear waves, because the shear wave is spatially smaller than the ROI.

An ultrasonic diagnostic apparatus according to an embodiment includes a setting unit, a transmitter, a signal processing unit, and an image generating unit. The setting unit sets a plurality of ROIs within a scanning region. The transmitter transmits an ultrasonic wave for displacement generation on a plurality of transmission conditions corresponding to the respective ROIs from an ultrasonic probe and transmits an ultrasonic wave for observation that observes a displacement generated by each transmission of the ultrasonic wave for displacement generation, from the ultrasonic probe a plurality of times. The signal processing unit analyzes a plurality of pieces of reflected wave data, acquires a plurality of pieces of displacement information, and calculates distribution information on the respective transmission conditions. The image generating unit generates a plurality of pieces of image data based on the pieces of distribution information and composite image data by composing the pieces of image data.

Classification preprocessing is provided for medical ultrasound shear wave imaging. In response to stress, the displacement at one or more locations in a patient is measured. The displacement over time is a curve representing a shift in location. One or more characteristics of the curve, such as signal-to-noise ratio and maximum displacement, are used to classify the location. The location is classified as fluid or fluid tissue, solid tissue, or non-determinative. Subsequent shear imaging may provide shear information for locations of solid tissue and not at other locations.

Ultrasound radiation using a single tone burst pulse is applied to a selected location in a tissue region. The induced shear wave is detected in the region and its spectral distribution is calculated and analyzed. This detection may be repeated with other excitation pulses having different widths or different shapes at the same location. The spectral analysis of the detected shear wave is performed according to a nonlinear shear model for solving nonlinearity and viscoelasticity of the tissue at a single location. The detection location can be at one point at a time for imaging two-dimensional or three-dimensional tissue nonlinearities and shear wave properties including nonlinear magnitude variations, nonlinear phase variations, nonlinear coefficients, and viscoelasticity. The induced shear wave are detected at multiple locations along the shear propagation directions for calculating different shear group velocities and different shear phase velocities using different excitation pulses, and calculating nonlinearity and viscoelasticity.

Methods, systems, and computer readable media for taking measurements of a material, including determining material anisotropy, are provided. According to one aspect, a method for determining tissue anisotropy comprises: applying, to a tissue sample, a first force having a direction and having a coronal plane normal to the direction of the force, the first force having an oval or other profile with long and short axes within the coronal plane, the long axis being oriented in a first direction within the coronal plane, and measuring a first displacement of the tissue; applying, to the tissue sample, a second force, and measuring a second displacement of the tissue; and calculating a tissue elasticity anisotropy based on the measured first and second displacements. Furthermore, by applying the first and second forces multiple times, tissue viscosity, elasticity, or other anisotropy may be calculated from the multiple displacement measurements.

An ultrasound diagnostic apparatus includes: a probe that includes a transducer array including transducers, which are activated as a first transducer group and a second transducer group, is configured to transmit ultrasound waves by at least one transducer included in the first transducer group and at least one transducer included in the second transducer group, and to detect echo signals from an object; and a controller configured to select a number of transducers to be activated in the first transducer group and in the second transducer group based on the object or a measurement result, generate echo images from the echo signals, and measure an object change movement speed, which is a speed at which a change in the object moves, from the echo images.

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.

A system and method includes transmission of an ultrasound push pulse toward material along a first axis, the ultrasound push pulse associated with a first frequency, a first F number, and a first focal depth, determination of displacement of the material along the axis in response to the push pulse, transmission of a second ultrasound pulse toward the material along the first axis, the second ultrasound pulse associated with a second frequency, a second F number, and a second focal depth substantially similar to the first frequency, the first F number, and the first focal depth, respectively, reception of echo signals from the material in response to the second ultrasound pulse, beamforming of the echo signals based on the first F number and a fixed focus at the first focal depth, determination of a magnitude of the beamformed echo signals along the axis, determination of relative elasticity of the material along the axis based on the determined displacement of the material along the axis and the magnitude of the beamformed echo signals along the axis, and generation of an image based on the determined relative elasticity of the material along the axis.

A shear wave elasticity measurement method and a shear wave elasticity imaging system are disclosed. For each pair of corresponding shear waves, an echo signal within a continuous period of time can be obtained only at a third position, so that an elasticity parameter corresponding to the target area can be obtained according to the echo signal within the continuous period of time. Not only the position required for obtaining an echo signal is few, but also the total data volume required for obtaining the echo signal is few. The calculation method is also easy, which significantly reduces the system performance requirement.