A particular sequence of ultrasound transmissions and corresponding echo receptions enables the production of Amplitude Modulated (AM) and Amplitude Modulated Phase Inverted (AMPI) signals that are temporally balanced. Temporal balancing significantly reduces tissue artifacts caused by movement of tissue during acquisition of the ultrasound echoes. Additionally, in combining the selected echo signals to produce the AM5 and AMPI signals, and optionally a Phase Inverted (PI) signal, each of the echo signals is equally weighted to facilitate an amplitude balance that avoids different echoes affecting the produced AM, AMPI, and PI signals differently.

Super-resolution ultrasound imaging of microvessels in a subject is described. Ultrasound data are acquired from a region-of-interest in a subject who has been administered a microbubble contrast agent. The ultrasound data are acquired while the microbubbles are moving through, or otherwise present in, the region-of-interest. Microbubble signals are isolated from the ultrasound data and are separated into subsets of data based on properties of the microbubbles, such as spatial-temporal hemodynamics. By localizing, tracking, and accumulating the microbubbles in each subset of data, super-resolution images of the microvessels can be generated for each subset, such that each of these images represents a sparse subset of microbubble signals. These images are combined to generate a super-resolution microvessel image.

A method for producing an image of at least one vessel with ultrasound includes administering a contrast agent particle into the at least one vessel, and delivering an ultrasound pulse having a first frequency range to the at least one vessel. The method further includes detecting ultrasound energy scattered from the contrast agent particle at a second frequency range that is different from the first frequency range, converting the scattered ultrasound energy into an electronic radio frequency signal, and using an algorithm to determine a spatial location of the contrast agent particle based on extraction of a specific feature of the radio frequency signal. The method further includes generating an image by displaying a marker of the spatial location of the contrast agent particle with a resolution that is finer than a pulse length of the ultrasound pulse and repeating the detecting, converting, using, and generating for a plurality of contrast agent particles until sufficient markers have been accumulated to reconstruct a pattern of the at least one vessel; wherein the pattern is an image of the at least one vessel.

An apparatus includes a processor and a display. The processor includes a combiner configured to combine contrast data acquired with a same sub-aperture, for each of a plurality of sub-apertures, to create a contrast frame for each of the sub-apertures. The processor includes a microbubble detector configured to determine positions of microbubbles in the contrast frames. The processor includes a motion estimator configured to estimate a motion field based on frames of B-mode data for each of the plurality of sub-apertures. The processor includes a motion corrector configured to motion correct the positions of the microbubbles in the contrast frames based on the motion field and time delays between emissions for the sets of contrast data and the emission for B-mode data, for each of the plurality of sub-apertures, to produce motion corrected contrast frames. The display is configured to display the motion corrected contrast frames as super resolution images.

Systems and methods for high spatial and temporal resolution ultrasound imaging of microvessels in a subject are described. Ultrasound data are acquired from a region-of-interest in a subject who has been administered a microbubble contrast agent. The ultrasound data are acquired while the microbubbles are moving through, or otherwise present in, the region-of-interest. The region-of-interest may include, for instance, microvessels or other microvasculature in the subject. By imaging microbubbles, a cross-correlation map between each microbubble image and a point spread function of the system can be generated. Accumulation of power-based cross-correlation maps may then be used to generate a high-resolution high-contrast image of the microvasculature.

Various approaches to generating and maintaining an ultrasound focus at a target region include configuring a controller to cause transmission of treatment ultrasound pulses from a transducer having multiple transducer elements; cause the transducer to transmit focusing ultrasound pulses to the target region and generate an acoustic reflector therein; measure reflections of the focusing ultrasound pulses from the acoustic reflector; based at least in part on the measured reflections, adjust a parameter value associated with one or more transducer elements so as to maintain and/or improve the ultrasound focus at the target region.

The present disclosure describes ultrasound systems configured to perform microbubble-based contrast imaging with enhanced sensitivity. The systems can enhance echo signals derived from microbubbles while suppressing echo signals derived from tissue by detecting phase shifts exhibited by microbubbles in resonance. To detect the phase shifts, and thereby distinguish between microbubble-based signals and tissue-based signals, the systems can transmit a series of ultrasound pulses into a target region in accordance with a predefined sequence. The sequence can include an initiation pulse configured to stimulate microbubbles into nonlinear oscillation, a detection pulse configured to detect the nonlinear oscillation, and a summation pulse formed by transmitting an initiation pulse and detection pulse with a small time delay therebetween. A signal processor included in the system can determine phase shifts exhibited by the signals generated in response to the series of pulses and mask non-microbubble-based signals based on the magnitude of the detected phase shifts.

A method for determining a physical characteristic on a punctual location inside a medium, comprising the steps of: sending an emitted sequence comprising emitted pulses having different amplitudes, receiving a received sequence comprising received pulses corresponding to echoes of said emitted pulses, calculating a phase difference between the received pulses relative to the emitted pulses, and determining the physical characteristic on the bases of said phase difference.

A signal processing device according to an embodiment includes adjustment circuitry and processing circuitry. The adjustment circuitry adjusts a received signal based on an echo of an ultrasonic wave transmitted to a subject with gain corresponding to a location at which the echo has been generated. The processing circuitry corrects the received signal that has been adjusted by the adjustment circuitry and calculates an index value relating to attenuation by using the corrected received signal.

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.