Techniques, systems, and devices are disclosed for synthetic aperture ultrasound imaging using spread-spectrum, wide instantaneous band, coherent, coded waveforms. In one aspect, a method includes synthesizing a composite waveform formed of a plurality of individual orthogonal coded waveforms that are mutually orthogonal to each other, correspond to different frequency bands and including a unique frequency with a corresponding phase; transmitting an acoustic wave based on the composite waveform toward a target from one or more transmitting positions; and receiving at one or more receiving positions acoustic energy returned from at least part of the target corresponding to the transmitted acoustic waveforms, in which the transmitting and receiving positions each include one or both of spatial positions of an array of transducer elements relative to the target and beam phase center positions of the array, and the transmitted acoustic waveforms and the returned acoustic waveforms produce an enlarged effective aperture.

An ultrasound system includes a transducer array having three or more rows of transducer elements extending in the azimuth dimension and located adjacent to each other in the elevation dimension. The rows have different mechanical foci in the elevation dimension, with an inner row elevationally focused in the near field and outer rows elevationally focused in the far field. When the user is imaging a subject in the near field, the system beamformer transmits with the inner row with a near field elevation focus. When imaging in the far field a plurality of rows elevationally focused in the far field are used for transmission. When the user is imaging in the mid-range, the beamformer uses both the inner row and the plurality of outer rows to provide an extended mid-range elevation focus.

A digital transmit beamformer for an ultrasound system has a waveform sample memory which stores sequences of samples of different pulse transmit waveforms of differing pulse widths. The memory is shared by a plurality of transmit channels, each of which can access its own selected sample sequence, independent of the selections by other channels. Waveform sample readout by the channels occurs substantially simultaneously during a transmit event, producing a transmit beam from a transmit aperture with different pulse waveforms applied to different elements of the transmit aperture. Higher energy waveforms with wider pulse widths are applied to central elements of the aperture and lower energy waveforms with narrower pulse widths are applied to lateral elements of the aperture to produce an apodized transmit beam.

An ultrasonic image is obtained from a bias-switchable row-column array transducer. A row channel data set is obtained by applying a bias voltage pattern to groups of row electrodes, the bias voltage pattern being chosen such that row electrodes within each group have the same bias voltage; transmitting a waveform along each of the plurality of row electrodes; and recording received column signals from each of the plurality of column electrodes. A column channel data set is obtained by applying a bias voltage pattern to groups of column electrodes, the bias voltage pattern being chosen such that column electrodes within each group have the same bias voltage; transmitting a waveform along each of the plurality of column electrodes; and recording received row signals from each of the plurality of row electrodes.

A system for coherence imaging may receive ultrasound signals each having a respective delay associated with a respective ultrasonic transducer element in an ultrasonic transducer array. The system may obtain an approximation of the auto-correlation of ultrasound signals without any auto-correlation calculation, and determine the output image based on the approximation. In approximating the auto-correlation, the system may group the ultrasound signals into multiple portions, each corresponding to a respective sub-aperture of a plurality of sub-apertures of the ultrasonic transducer array. The system may determine a coherent sum of signals for each sub-aperture, perform a square operation or magnitude square operation over the coherent sum to obtain resulting data, normalize the resulting data, and sum the resulting data for all of the sub-apertures to generate the output image. A sub-aperture in the plurality of sub-apertures may overlap with another sub-aperture.

Techniques, systems, and devices are disclosed for ultrasound diagnostics using spread spectrum, coherent, frequency- and/or phase-coded waveforms. In one aspect, a method includes synthesizing individual orthogonal coded waveforms to form a composite waveform for transmission toward a biological material of interest, in which the synthesized individual orthogonal coded waveforms correspond to distinct frequency bands and include one or both of frequency-coded or phase-coded waveforms; transmitting a composite acoustic waveform toward the biological material of interest, where the transmitting includes transducing the individual orthogonal coded waveforms into corresponding acoustic waveforms to form the composite acoustic waveform; receiving acoustic waveforms returned from at least part of the biological material of interest corresponding to at least some of the transmitted acoustic waveforms that form the composite acoustic waveform; and processing the received returned acoustic waveforms to produce an image of at least part of the biological material of interest.

A transducer array includes at least one annular shear wave generation transducer that defines an interior area, the at least one annular shear wave generation transducer being configured to generate a shear wave excitation to a region of interest such that the shear wave excitation excites at least a part of a corresponding cylindrical portion of the region of interest and shear waves propagating from the cylindrical portion of the region of interest constructively interfere in an interior region of the cylindrical portion of the region of interest; and at least one tracking transducer positioned in the interior area of the at least one annular shear wave generation transducer, the at least one tracking transducer being configured to detect a shear wave in the interior region of the region of interest.

An acoustic dual-frequency phased array system with common beam angles is disclosed. In one aspect, the system includes a planar array of transducer elements and a multiplexing circuit for selecting between a first state and a second state during either transmit operation, receive operation or both transmit and receive operation. The multiplexer is configured to connect transducer elements to a plurality of connections different between the first state and second state. The system is configured to transmit and receive beams at a first frequency when the multiplexer is in the first state and transmit and receive beams at a second frequency when the multiplexer is in the second state. The angle of the beams from vertical in the first and second state are substantially similar.

A switch circuit connected to a transducer, a reception circuit connected to the switch circuit, a first switch element connected to a reception terminal provided between the switch circuit and the reception circuit, a first resistance element connected to a control terminal of the switch circuit, a second resistance element provided inside the reception circuit, and a second switch element provided inside the reception circuit are provided.

An acoustic imaging probe having an adjustable effective elevation length. The acoustic 5imaging probe has a transducer element, comprising a plurality of acoustic transducers, that is divided into a plurality of sets of adjacent transducers. A processing module controls how many sets contribute to an acoustic pulse emitted by the acoustic transducer element during an imaging process, to thereby adjust an effective elevation length of the acoustic imaging probe.