Abstract: Provided herein are systems, devices, and methods for ultrasound imaging particular to matrix arrays of ultrasound transducer assemblies which each comprise a matrix array of transducer elements and an ASIC coupled to the matrix array of transducer elements. The matrix array of ultrasound transducer assemblies can be assembled into a variety of form factors. Virtual elements located in gaps between transducer assemblies may be defined. Synthesized receive signals may be generated for these virtual elements.

Abstract: The present disclosure provides an ultrasound imaging system comprising an array of transducer elements, a plurality of receive circuits configured to provide one or more output signals, a plurality of delay circuits configured to output one or more delayed signals, and at least one multi-channel beamformer configured to (i) receive representations of a plurality of microbeamformed signals and (ii) output at least one representation of a beamformed signal. The plurality of microbeamformed signals may represent a combination of delayed signals from the plurality of delay circuits. The plurality of delay circuits may be characterized by a plurality of time delay values. The plurality of time delay values may be controllable or adjustable such that one or more points-of-focus characterizing the microbeamformed signals can move along a line of sight.

Abstract: Methods and systems for ultrasound imaging and beamforming with a matrix array of transducer elements are provided. Receive signals of each transducer array element are amplified. The amplified receive signal of each transducer array element is digitized. A delay and weight are applied on the amplified and digitized receive signals. The amplified, digitized, delayed, and weighted receive signals are summed across all transducer elements of the matrix array to form a dynamically focused receive beam. An application specific integrated circuit (ASIC) that is integrated with the matrix array of transducer elements performs such steps.

Abstract: Disclosed herein are computer-implemented medical ultrasound imaging methods, and systems for performing the methods, that comprise forming a first frame of an ultrasound image sequence with high image quality; forming at least one frame of the ultrasound image sequence with reduced image quality; forming a second frame of the ultrasound image sequence with high image quality; and improving the quality of the at least one frame of the ultrasound image sequence with reduced image quality using the first and/or the second frames of the ultrasound image sequence with high quality. In some cases, the improvement of the quality of the at least one frame of the ultrasound image sequence with reduced image quality is achieved by application of machine learning.

Abstract: Artifacts in ultrasound displacement images are reduced by combining multiple component displacement images. For each component displacement image first a pre-displacement ultrasound image is generated from a particular imaging angle. Then a displacement force is applied on the object at a desired displacement angle via an ultrasound or other mechanical force. Then a post-displacement ultrasound image is generated from the same imaging angle. A component displacement image is generated by correlating the pre-displacement and post-displacement ultrasound images. The above steps are repeated for at least one other (imaging angle, displacement angle) pair, and the resulting component displacement images are combined to reduce displacement image artifacts.

Abstract: Adaptive grating lobe suppression is provided. Received ultrasound data is measured, compared or otherwise processed to determine the presence of grating lobe energy. A further process is then altered as a function of the level of grating lobe energy. In one embodiment, the adaptive grating lobe suppression is implemented in the receive beamformer. Data representing a virtual element is formed as a normalized sum of data from adjacent sparse elements. The data from the adjacent elements is correlated to determine the presence of grating lobe energy as a function of the amount of shift associated with the peak correlation. A phase shift is applied to the data representing the virtual element where sufficient grating lobe energy is determined. In another embodiment, an amount of grating lobe energy is measured by comparing data from prior to a filter with filtered data. The filter is selected to isolate main lobe energy from grating lobe energy.

Abstract: Adaptive line synthesis is provided. Line synthesis of collinear receive beams responsive to spatially distinct transmit beams is a function of many parameters, such as spatial or temporal frequency response of one or more of the receive beams, synthesis function, number of receive beams synthesized, or acquisition sequence. One or more of these parameters is set or adapts as a function of processor estimated or user provided information. By adapting the line synthesis, the performance and image quality is optimized as appropriate for the received data or desired imaging, such as detail resolution, contrast resolution, temporal resolution, shift-invariance and penetration.

Abstract: Phase unwrapping is applied to velocity data to remove aliasing artifacts. Phase unwrapping is applied on multidimensional regions of velocity data. The unwrapped velocity image is displayed. The displayed image may have high sensitivity to slow motion but may also avoid aliasing of fast motion despite being undersampled.

Abstract: Diagnostic ultrasound flow imaging is performed with coded excitation pulses. Due to the use of frequency coded excitation pulses, flow information may suffer from spatial misregistration and estimate errors. Spatial position shift in flow data is offset for alignment with B-mode or other imaging. The flow estimates are compensated for the imaging center frequency variation with depth. The wide bandwidth information available due to coded excitation may allow anti-aliasing by estimating velocities from two frequency bands.

Abstract: The depth buffer of a GPU is used to derive a surface normal or other surface parameter, avoiding or limiting computation of spatial gradients in 3D data sets and extra loading of data into the GPU. The surface parameter is used: to add shading with lighting to volume renderings of ultrasound data in real time, to angle correct velocity estimates, to adapt filtering or to correct for insonifying-angle dependent gain and compression. For border detection and segmentation, intersections with a volume oriented as a function of target structure, such as cylinders oriented relative to a vessel, are used for rendering. The intersections identify data for loading into the frame buffer for rendering.

Abstract: Aberration estimation uses cross correlation of receive-focused transmit element data. A set of sequentially fired broad transmit beams insonify an object from different steering angles. Each transmit beam emanates from an actual or a virtual transmit element. For every firing, a receive beamformer forms a transmit element image of the insonified region by focusing the received signals. An estimator estimates aberration by cross correlating or comparing the transmit element images. Where a virtual transmit element is used, the virtual transmit element images are back propagated to an actual transmit element position before aberration estimation. The estimations are used to form corrected transmit element images which are then summed pre-detection to form a high-resolution synthetic transmit aperture. Alternatively, the estimations are used to improve conventional focused-transmit imaging.

Abstract: Transmit multibeams insonify an object with multiple noncollinear transmit beams fired substantially simultaneously. The noncollinear beams are along different scan lines of same scan geometry, or they belong to scan lines of different scan geometries. One or more receive beams are formed in parallel in response to each of the noncollinear beams. The scan geometry and/or center frequency is varied between the noncollinear transmit beams of a transmit event. By scanning the transmit multibeam, and varying the scan geometry and/or frequency between the noncollinear transmit beams of a transmit event, multiple component images are generated for compounding. The component images are scan-converted (if scan geometries are different), weighted and combined after envelope detection.

Abstract: A set of N×M signals are acquired from an object, where N is the number of array elements and M corresponds to variations in data acquisition and/or processing parameters. The parameters include transmit aperture functions, transmit waveforms, receive aperture functions, and receive filtering functions in space and/or time. A coherence factor is computed as a ratio of the energy of the coherent sum to the energy of the at-least-partially incoherent sum of channel or image signals acquired with at least one different parameter. Partial beamformed data may be used for channel coherence calculation. For image domain coherence, a component image is formed for each different transmit beam or receive aperture function, and a coherence factor image is computed using the set of component images. The coherence factor image is displayed or used to modify or blend other images formed of the same region.

Abstract: Multiple apexes or intersections of scan lines are used to control the desired scan region for three dimensional scanning. Where a two dimensional transducer array is not square or circular or if the element spacing in azimuth and elevation is unequal, multiple apexes allow for optimization of the scanned volume to the transducer characteristics. The different apexes may be spaced from each other and relative to the transducer at various locations. Distributed patterns of apexes may be provided, such as spacing a plurality of apexes along a line in elevation and another set of apexes along a line in azimuth.

Abstract: An effective method to attain high volume rates in real-time three-dimensional ultrasound imaging is to reduce the lateral scan extent in azimuth and/or elevation. Reducing the scan extent, however, may make it difficult to determine the anatomical orientation during scan, or post-scan review. Anatomical landmark information is provided, with only a small impact on the volume rate by scanning along a two-dimensional plane with a greater lateral extent than a three-dimensional volume scan or by scanning over a three-dimensional volume with a lower resolution than a higher resolution sub-volume scan. The lower resolution three-dimensional image or the two-dimensional image scan provides anatomical landmark information. The higher resolution or smaller three-dimensional volume scan provides information for diagnosis of a specific region with three-dimensional imaging.

Abstract: Ultrasound imaging adapts as a function of a coherence factor. Various beamforming, image forming or image processing parameters are varied as a function of a coherence factor to improve detail resolution, contrast resolution, dynamic range or SNR. For example, a beamforming parameter such as the transmit or receive aperture size, apodization type or delay is selected to provide maximum coherence. Alternatively or additionally, an image forming parameter, such as the number of beams for coherent synthesis or incoherent compounding, is set as a function of the coherence factor. Alternatively or additionally an image processing parameter such as the dynamic range, linear or nonlinear video filter and/or linear or nonlinear map may also adapt as a function of the coherence factor.

Abstract: Transducer systems for mode dependent tuning and associated methods are provided. One or more tuning circuits are provided within a transducer probe. The tuning circuit is switchably connected to the transducer. By connecting or disconnecting the tuning circuit, the tuning for the transducer element is varied. Selective tuning of a medical ultrasound transducer allows different tuning for different modes of operation. For example, the frequency response of the transducer is varied between different modes of imaging, such as B-mode and flow-mode imaging. Higher frequency signals are used for higher resolution B-mode imaging, but a stronger response at lower frequency is desired for better penetration during flow-mode imaging and Doppler modes. Mode is used in a general sense, such as associated with an imaging mode as well as a type of operation (e.g. transmit mode versus receive mode operation).

Abstract: Transmit based axial whitening is provided. Ultrasonic waveforms to be transmitted are designed to provide for wideband imaging characteristics prior to detection. Rather than transmitting a waveform having a spectral magnitude as white or flat as possible, waveforms with adjusted spectral content, such as spectrally bi-modal waveforms are generated in order to compensate for subsequent effects. Prior to detection, a more wideband or whiter signal response is provided in response to the transmitted waveform. Any of various alterations of the transmit waveform, such as asymmetric, spectrally bi-modal or other characteristics in anticipation of a system transfer function or physical phenomena through which the signal passes electronically or acoustically to result in a wideband or white spectral magnitude and generally linear spectral phase is used. The transmit waveform is altered to improve the imaging characteristics of the downstream processing.

Abstract: A medical imaging system automatically acquires two-dimensional images representing a user-defined region of interest despite motion. The plane of acquisition is updated or altered adaptively as a function of detected motion. The user-designated region of interest is then continually scanned due to the alteration in scan plane position. A multi-dimensional array is used to stabilize imaging of a region of interest in a three-dimensional volume. The user defines a region of interest for two-dimensional imaging. Motion is then detected. The position of a scan plane used to generate a subsequent two-dimensional image is then oriented as a function of the detected motion within the three-dimensional volume. By repeating the motion determination and adaptive alteration of the scan plane position, real time imaging of a same region of interest is provided while minimizing the region of interest fading into or out of the sequence of images.

Abstract: To improve real time 3D imaging performance, acquisition, beamforming, coherent image forming and/or image processing parameters are varied as a function of the viewing direction selected by the user. For example, the scan planes are oriented relative to the viewing direction. As a result rapid 3D rendering is provided without complex additional data interpolation or other 3D rendering processes. In another example, data along the lateral axis that is perpendicular to the viewing direction (i.e., display lateral axis) is acquired with parameters adapted to maximize field of view, detail and contrast resolution, while data along the lateral axis that is parallel to the viewing direction is acquired with compromised field of view, detail or contrast resolution. As a result, a high volume rate 3D imaging is achieved with 2D-equivalent detail resolution, contrast resolution and field of view along the display lateral axis.