Ultrasonic imaging device

Abstract

An ultrasonic imaging apparatus for providing volumetric ultrasonic images of an image volume, the ultrasonic imaging apparatus comprising: a matrix addressable transducer array configured to convert an excitation electrical pulse into an ultrasonic pressure field and convert a received ultrasonic echo pressure field into an echo signal; a beamformer module configured to beamform the echo signal using dynamic receive focusing to generate respective image values at a first set of image points within the image volume; and a reconstruction module configured to determine a set of trajectories, each trajectory intersecting one of the image points of the first set of image points, map a second set of image points of the image volume to the first set of image points, and calculate respective image values at the mapped image points of the second set of image points from the image values of the image points of the first set of image points.

Description

Technical Field

[0001] The following generally relates to ultrasound, and more particularly to an ultrasound imaging device, a corresponding method, a data processing system, and a computer program.

Background Art

[0002] By using a 2D probe combined with synthetic aperture imaging, high frame rate 3D imaging with a wide volumetric coverage can be achieved. However, in most 2D probe designs, the number of channels increases on the order of the square of the number of elements in the side length of the aperture. This makes it very difficult, if not impossible, to achieve a low F-number at large imaging depths from a manufacturing and processing perspective. Furthermore, even when the number of elements in the side length of the aperture is small, the number of channels far exceeds that of a typical 2D imaging device.

[0003] A row-column addressing array (RCA) provides a solution to the large number of channels by addressing the elements of a 2D array by rows and columns, such that the total number of channels decreases linearly rather than on the order of the square of the number of elements in the side length of the aperture.

[0004] US10,705,210 discloses an ultrasound imaging device for three-dimensional imaging by a row-column addressing transducer array using synthetic aperture sequential beamforming. This prior art method applies a fixed focus to simplify the propagation path of the sound waves.

[0005] Row-column imaging using dynamic receive focusing is another approach to row-column imaging. Dynamic receive focusing models the propagation of sound waves more accurately, and most current ultrasound scanners use this approach for imaging.

[0006] Regarding matrix imaging using dynamic receive focusing, it is described in M. F. Rasmussen, T. L. Christiansen, E. V. Thomsen, and J. A. Jensen, “3-D imaging using row-column-addressed arrays with integrated apodization - Part I: Apodization design and line element beamforming,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., vol. 62, no. 5, pp. 947-958, 2015.

[0007] L.Th. Jorgensen et al., ”Tensor Velocity Imaging With Motion Correction”, IEEE Transactions on ultrasonics, ferroelectrics, and frequency control, Vol. 66, No. 5, May 2021 introduces a motion correction procedure that improves the accuracy of synthetic aperture tensor velocity estimation for matrix arrays.

[0008] Matrix imaging using dynamic receive focusing is known to provide high image quality, but this approach places high demands on the processing unit. This is particularly a serious problem when volumetric images are acquired because volumetric images usually contain a large number of image points. In particular, high processing power severely limits the pulse repetition frequency at which real-time imaging can be performed. However, high pulse repetition rates are required in many clinical applications, such as real-time flow applications.

[0009] Therefore, it is still desirable to provide an imaging device that facilitates high pulse repetition frequencies, such as real-time volumetric beamforming, while providing high image quality.

[0010] Considering at least the above, there is a need for an improved approach to matrix ultrasound imaging that remains unresolved. SUMMARY OF THE INVENTION

[0011] The various aspects disclosed herein are aimed at addressing the above and / or other matters, or at least providing an approach that can serve as an alternative to existing approaches.

[0012] According to one aspect, an ultrasonic imaging device for providing volumetric ultrasonic images of an image volume is disclosed. The term volumetric ultrasonic image is intended to refer to a 3D ultrasonic image, which may be represented as a 3D raster of image points, for example, each image point having an associated image value.

[0013] Embodiments of the ultrasonic imaging device a) a matrix addressable transducer array, and b) a beamforming module, and c) a reconstruction module are provided.

[0014] The matrix addressable transducer array is configured to convert an excitation electrical pulse into an ultrasonic pressure field and to convert the received ultrasonic echo pressure field into an echo signal. The beamformer module is configured to beamform the echo signals using dynamic receive focusing to generate respective image values at a first set of image points within the image volume.

[0015] The reconstruction module A set of trajectories, each trajectory intersecting one of the image points of the first set of image points, and each of the determined trajectories being defined by a position such that, depending on the virtual emitter position, in particular the time of flight from the virtual emitter position to the closest position on one of the receiving apertures of the first and second transducer arrays is constant along the trajectory, determining a set of trajectories, Mapping the image points of the second set of the image volume to the image points of the first set, Calculating, from the image values of the image points of the first set of image points, the respective image values at the mapped image points of the second set of image points, thereby obtaining a volumetric ultrasound image of the image volume is configured as follows.

[0016] The ultrasound imaging apparatus may be configured to control a matrix-addressing transducer array to perform a plurality of ultrasound emissions corresponding to ultrasound radiated from respective virtual emitter positions, a beamformer module and a reconstruction module being configured to calculate a plurality of low-resolution volumetric images, each low-resolution volumetric image corresponding to a respective virtual emitter position, and the imaging apparatus further comprising an image combiner module configured to combine the plurality of low-resolution volumetric images corresponding to different virtual emitter positions into a combined high-resolution volumetric image having a higher spatial resolution than the low-resolution volumetric images.

[0017] Embodiments of the ultrasound imaging apparatus disclosed herein can provide a volumetric image that is indistinguishable from prior art matrix imaging methods with dynamic receive focusing, but with considerably fewer operations.

[0018] In prior art matrix imaging using dynamic receive focusing, the number of processing operations is proportional to the product of the number of elements in the array and the number of image points. In embodiments of the approach used in the various aspects disclosed herein, the number of operations is proportional only to the number of image points. The inventors have realized that this reduction can be achieved because there are positions within the volume where the measured time of flight of the sound is constant up to the position closest to the aperture. As a result, the image values along these positions are also approximately constant. This means that the imaging device only needs to calculate the image value at any one of those positions in order to obtain the image values at all the remaining positions. The various embodiments disclosed herein utilize this recognition in 3D imaging, thereby achieving a significant reduction in the number of processing operations and facilitating real-time image acquisition at higher pulse frequencies. Real-time image acquisition at higher pulse frequencies facilitates various applications such as clinical applications. Examples of such applications include, but are not limited to, velocity imaging such as anatomical imaging, super-resolution imaging, contrast imaging, tensor velocity imaging, etc.

[0019] The matrix-addressable transducer array includes a plurality of transducer elements. The transducer elements can be configured to convert an excitation electrical pulse into an ultrasonic pressure field and to convert the received ultrasonic pressure field (echo) into an electrical (e.g., radio frequency (RF)) echo signal. The echo, and thus the echo signal, is generated in response to the transmitted pressure field interacting with a substance such as tissue. Thus, an ultrasonic imaging device can include a transmit circuit configured to generate excitation electrical pulses to cause the matrix-addressable transducer array, in particular, to perform a sequence of emissions of ultrasonic pressure fields corresponding to respective virtual emitter positions.

[0020] The matrix transducer array may include a first set of transducer elements that define a first transducer array, particularly a first 1D transducer array, along a first axis. Each transducer of the first transducer array may extend along a first longitudinal axis that may be orthogonal to the first axis. Thus, the transducers of the first transducer array may be formed as rows or columns of a 2D array of transducer elements, and a single channel may be used to address the transducer elements of each row or column. Accordingly, each column or row may be addressable as a single elongated transducer of a 1D array of transducers. The matrix transducer array may include a second set of transducer elements that define a second transducer array, particularly a second 1D transducer array, along a second axis. Each transducer of the second transducer array may extend along a second longitudinal axis that may be orthogonal to the second axis. Thus, the transducers of the second transducer array may be formed as columns or rows of a 2D array of transducer elements, and a single channel may be used to address the transducer elements of each column or row. The first axis may be orthogonal to the second axis. In particular, the matrix addressing array may define two elongated 1D transducer arrays, one consisting of row elements of a 2D array of transducer elements and the other consisting of column elements.

[0021] In some embodiments, the imaging device is configured to transmit ultrasonic waves by the first transducer array and receive the ultrasonic waves backscattered, i.e., the echoes, by the second transducer array.

[0022] The reconstruction module determines trajectories within the image volume. This determination can involve determining trajectories where the image values are constant or at least approximately constant. Thus, the reconstruction module can determine a trajectory as a set of positions within the image volume, such that the flight time from the virtual emitter position to the closest position on one of the receiving apertures of the first and second transducer arrays via any one of the set of positions along the trajectory is constant along the trajectory, i.e., the same for all positions of the set of positions. Thus, the set of trajectories are trajectories of constant flight time with respect to the virtual emitter position. The determination of the trajectories depends on the virtual emitter position. Thus, a determination is made for a set of virtual emitter positions, and as a result, a set of trajectories is obtained, with each trajectory of the set corresponding to a different virtual emitter position. The resulting representation of the trajectories, and / or the representation of the corresponding mapping of the image coordinates of the second set of image points to the image points of the first set along each of the determined trajectories, is stored in memory and can be reused for the creation of subsequent volumetric ultrasound images that utilize the same virtual emitter position. For this reason, in some embodiments, the reconstruction module is configured to map each image coordinate of the image volume to the image points of the first set and store a representation of the mapped image coordinates. Thus, the reconstruction module can be configured to calculate a plurality of volumetric images using the stored representation of the mapped image coordinates.

[0023] The volumetric ultrasound images obtained by RCA based on echo signals corresponding to a single virtual emitter position provide limited spatial resolution, particularly along the elongation direction of the receiving transducer element. To increase the spatial resolution, the imaging device may be configured to control a matrix addressed transducer array to create a transmission sequence that includes a plurality of ultrasound transmissions corresponding to the ultrasound emitted from respective virtual emitter positions. The virtual emitter positions may be distributed along the elongation direction of the individual receiving transducer elements and / or may be distributed at different distances from the array. Accordingly, the beamformer module and the reconstruction module may be configured to calculate a plurality of low-resolution volumetric images (LRV), each low-resolution volumetric image corresponding to a respective virtual emitter position. The imaging device may further comprise an image combiner module configured to combine a plurality of low-resolution volumetric images corresponding to different virtual emitter positions into a combined high-resolution volumetric image (HRV) having a spatial resolution higher than the corresponding resolution of the low-resolution volumetric images, along at least one spatial direction. The combination may include calculating the image value of the high-resolution volumetric image as the sum or weighted sum of the image values at the same image point of the respective low-resolution volumetric images.

[0024] Accordingly, various embodiments of the methods disclosed herein perform dynamic receive focusing along all three spatial axes. In particular, dynamic receive focusing along the elongation direction of the receiving transducer element, i.e., the second elongation axis, can be achieved by combining the low-resolution volumetric images obtained for different virtual emitter positions.

[0025] Therefore, the beamformer module may be configured to beamform echo signals provided by the transducer array in response to ultrasonic echoes received by the matrix addressed transducer array in response to emissions, to generate a corresponding plurality of two-dimensional images, each two-dimensional image corresponding to one of the virtual emitter positions. Next, the reconstruction module may be configured to calculate at least a first low-resolution volumetric image among the plurality of low-resolution volumetric images, the first low-resolution image corresponding to the first virtual emitter position. For this reason, the reconstruction module may be configured to perform interpolation. The configuration module determines at least a first set of trajectories associated with the first virtual emitter position, uses the first set of trajectories to map the image coordinates of the image volume to the image positions of the first two-dimensional image, interpolates the image values at the mapped image coordinates from the image values of the first two-dimensional image plane, wherein the interpolated image values at the mapped image coordinates represent the first low-resolution volumetric image, and may calculate at least the first low-resolution volumetric image thereby.

[0026] The beamformer module may be configured to perform delay-and-sum beamforming and calculate image values at a first set of image points. Beamforming of echo signals using dynamic receive focusing generally involves applying respective delays to the responses of individual receive transducer elements transmitted from the image points and coherently adding these delayed responses. The delay is determined from the propagation time of the radiated wave from the transmission origin, i.e., the virtual source position, to the image point, and the round-trip time-of-flight (TOF) back to one of the transducer elements of the receive transducer array. Thus, beamforming may include calculating the time-of-flight for each virtual emitter position and each image point of the first set of image points. In particular, thus, for each image point, a new set of delay values is calculated.Thus, beamforming of the echo signals using dynamic receive focusing involves calculating the time-of-flight along the shortest path from the virtual emitter position to the image point and further from the image point to the receive transducer elements of the matrix-addressable transducer array or the receive aperture, as described, for example, in M. F. Rasmussen, T. L. Christiansen, E. V. Thomsen, and J. A. Jensen, “3-D imaging using row-column-addressed arrays with integrated apodization - Part I: Apodization design and line element beamforming,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., vol. 62, no. 5, pp. 947-958, 2015 or Stuart et al., “Real-time volumetric synthetic aperture software beamforming of row-column probe data,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., April 8, 2021, and the time-of-flight associated with the virtual emitter position and the image point can be calculated from the path length of the shortest path extending along the elongated receive transducer elements from the virtual emitter position to the image point and from the image point to the receive transducer elements of the second transducer array, particularly to the position closest to the image point.

[0027] The first set of image points can define a two-dimensional image plane, preferably an image plane, within the image volume, i.e., all the image points of the first set of image points can be present on the two-dimensional image surface. Thus, the image values of the image points among the first set of image points can represent a two-dimensional image. The two-dimensional image can be considered as a 2D projection of the image volume onto the two-dimensional image surface, and the projection is defined by a trajectory. The two-dimensional image surface can be selected such that all the image points within the image volume can be mapped, particularly projected, onto the two-dimensional image surface by a set of trajectories. The second set of image points includes image points that are displaced from the two-dimensional image surface. It will be understood that the second set of image positions further includes the image points of the first set and is thus considered to be mapped onto itself. Thus, the image values at the second set of image points represent the volumetric ultrasound image of the image volume.

[0028] The image plane may extend orthogonally to the longitudinal direction of the receiving transducer element. The image plane may extend particularly orthogonally from the plane defined by the transducer array. In one embodiment, the position of the image plane along the longitudinal direction of the receiving transducer element corresponds to, particularly is equal to, the position of the virtual emitter position along the longitudinal direction of the receiving transducer element.

[0029] The beamforming module may be configured to calculate the image values at the image points distributed over the two-dimensional image surface, particularly the entire image plane, at an appropriate, for example, predetermined sampling rate or raster density. The sampling rate may be uniform or may vary across the image plane. For example, the sampling rate along one direction may be greater than that in the other direction. In some embodiments, the ultrasound imaging device is configured to sample the beamformed image plane at least at the Nyquist frequency along at least the direction extending from the plane defined by the transducer array, thereby facilitating accurate interpolation by the reconstruction module.

[0030] The apparatus may include one or more processing units programmed or otherwise configured to implement a beamformer module and / or a reconstruction module and / or a combiner module. The one or more processing units may include a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, and the like. The beamformer module and the reconstruction module may be implemented by the same processing unit or by separate processing units.

[0031] In some embodiments, the imaging device includes a probe and a console operably coupled to the probe. The probe includes a matrix addressed transducer array, and the console may include a processing unit that implements a beamformer module and / or a reconstruction module and / or a combiner module. In some embodiments, some of the signal processing, such as some or all of the beamforming operations, may be performed by a processing unit included in the probe.

[0032] In some embodiments, the imaging device includes a transmission circuit configured to generate an excitation electrical pulse to excite transducer elements, and a reception circuit configured to receive an electrical signal, such as an RF signal, generated by the transducer elements and optionally condition and / or preprocess the received signal. The transmission and / or reception circuits may be included in the console.

[0033] In some embodiments, the processing unit is configured to implement a processing pipeline that processes the received electrical signal, particularly the received RF signal, to create a representation of one or more volumetric ultrasound images.

[0034] The same and / or another processing unit may be configured to perform additional processing of one or more volumetric ultrasound images, for example, for velocity imaging and / or another type of 3D ultrasound imaging.

[0035] It will be appreciated that creating one or more ultrasonic images from the received electrical signals, and optional further processing, can be performed by a single processing unit. Alternatively, different acts may be distributed among multiple processing units. In some embodiments, the processing unit that performs signal processing and / or image processing is included in the console. In some embodiments, at least a portion of the signal processing and / or subsequent image processing may be performed by a computing device separate from the console. In this embodiment, an RF signal stored in memory, and / or a beamformed image stored in the memory of the computing device, or a beamformed image received from the console (e.g., via a suitable wired or wireless connection), can be loaded and processed in an image processing pipeline to generate a resulting 3D image.

[0036] The imaging device may further include a display and may be configured to display a representation of the generated volumetric image. The display may be included in the console or may be included in a separate computing device.

[0037] In another aspect, a method, particularly a computer-implemented method, is receiving echo signals from a matrix-addressable transducer array, the echo signals representing an ultrasonic echo pressure field received by the matrix-addressable transducer array in response to radiating an ultrasonic pressure field, beamforming the received echo signals using dynamic receive focusing to generate respective image values at a first set of image points within an image volume, determining a set of trajectories, each trajectory intersecting one of the image points of the first set of image points, mapping a second set of image points of the image volume to the first set of image points, Calculating, from the image values of the image points among the first set of image points, the respective image values at the mapped image points of the second set of image points, thereby obtaining a volumetric ultrasound image of an image volume including.

[0038] In yet another aspect, a computer program, when executed by a computer or other data processing system, includes instructions that cause the computer or other data processing system to perform the computer-implemented acts of the methods described herein. The computer program can be implemented as a computer-readable storage medium storing the instructions or as a data signal encoding the instructions.

[0039] According to another aspect, embodiments of a data processing system configured to perform the acts of the methods described herein are disclosed herein. In particular, the data processing system can store program code adapted to cause the data processing system to perform the steps of the methods described herein when executed by the data processing system. The data processing system can be embodied as a single computer or as a distributed system including multiple computers, such as a client-server system, a cloud-based system, etc.

[0040] Those skilled in the art will recognize further aspects of the present application upon reading and understanding the accompanying description.

[0041] The various aspects disclosed herein are not limited by the figures of the accompanying drawings and are presented by way of example, where like references indicate like elements in the drawings.

Brief Description of the Drawings

[0042]

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[0043] In the following, an ultrasonic imaging device and related methods for providing volumetric ultrasonic images of an image volume, and corresponding methods for alleviating one or more of the above-described drawbacks of conventional volumetric imaging approaches will be described. Generally, an ultrasonic imaging device a) a matrix-addressable transducer array configured to convert an excitation electrical pulse into an ultrasonic pressure field and convert a received ultrasonic echo pressure field into an echo signal, b) a beamformer module configured to beamform the echo signal using dynamic receive focusing to generate respective image values for a first set of image points in an image volume, particularly image points on an image plane within the image volume, c) a reconstruction module, determining a set of trajectories, each trajectory intersecting one of the image points of the first set of image points, mapping a second set of image points of the image volume to the first set of image points, particularly image points outside the image plane, calculating respective image values at the mapped image points of the second set of image points from the image values of the image points of the first set of image points, thereby obtaining a volumetric ultrasonic image of the image volume and a reconstruction module configured as such.

[0044] FIG. 1 shows an exemplary imaging device 102 configured for volumetric ultrasonic imaging of a subject. The imaging device 102 includes a probe 104 and a console 106, which interface with each other via suitable complementary hardware (such as electromechanical connectors 108 and 110 and cables 112 as shown) and / or a wireless interface (not shown).

[0045] Probe 104 includes a row-column addressed transducer array (RCA) 114 with a plurality of transducer elements 116. The transducer array 114 can include planar, curved, or other shapes, fully filled or sparse arrays, etc. The transducer elements 116 are configured to convert an excitation electrical pulse into an ultrasonic pressure field and convert the received ultrasonic pressure field (echo) into an electrical (e.g., radio frequency (RF)) echo signal. Thus, the echo signal is generated in response to the transmitted pressure field interacting with a substance, such as human tissue, other biological or non-biological materials. The transducer elements of the RCA are arranged in a 2D array.

[0046] Console 106 includes a transmit circuit (TX) 118 configured to generate an excitation electrical pulse to excite the transducer elements 116 and a receive circuit (RX) 120 configured to receive the RF signal generated by the transducer elements 116. In one embodiment, RX 120 (or other circuitry) is also configured to perform adjustment or preprocessing of the RF signal, such as amplification, digitization, etc. In the illustrated embodiment, a TX / RX controller 122 is configured to control TX 118 and RX 120 for the transmit and receive operations of the RCA. TX 118 and RX 120 address the transducer elements of the RCA by rows and columns, respectively. For this purpose, the signals received along a row or column are summed to create one signal per row or column. Thus, RCA 114 effectively forms two orthogonal 1D arrays with elongated transducer elements, as described, for example, in relation to FIGURE 2.

[0047] In one embodiment, TX118 and RX120 are controlled to cause the RCA to perform volumetric imaging by transmitting using one of the 1D arrays and receiving backscattered signals using the other 1D array or the same 1D array. For example, a subset (i.e., one or a subgroup) of the elements of the transmit array can be excited to simultaneously generate a pressure field that emits a focused beam corresponding to radiation from a virtual emitter position, particularly a virtual line emitter. All or a subset of the elements of the receive array can be used to receive echoes. This can be repeated for multiple different subsets of the transmit array, particularly for different positions of the virtual emitter, and each transmit / receive provides data for generating a low-resolution volumetric image, and a high-resolution volumetric image can be generated by combining a plurality of low-resolution images corresponding to different virtual emitter positions, as described herein. Examples of suitable sequences are described in Jensen et al., “Synthetic aperture ultrasound imaging,” Ultrasonics, vol. 44, pp. e5-e15, 2006. Another example using plane waves is described in Tanter et al., “Ultrafast imaging in biomedical ultrasound, IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2014, 61, 1, pp. 102-119.

[0048] The console 106 further includes a processing unit 124. The processing unit 124 includes one or more processors (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, etc.) configured to execute computer-readable instructions encoded or embedded on a computer-readable storage medium such as the memory 126 to perform the computer-implemented acts described herein. Generally, the processing unit 124 is configured to process RF signals to create a set of low-resolution volumetric ultrasound images and combine the low-resolution volumetric ultrasound images to generate a high-resolution volumetric ultrasound image. In particular, the processing unit 124 is configured to implement a processing pipeline including a beamformer module, a reconstruction module, and a combiner module as described herein.

[0049] As will be described in more detail below, in one example, the processing unit 124 implements a beamformer module, a reconstruction module, and a combiner module. The beamformer module beamforms the received echo signals to generate beamformed low-resolution image planes corresponding to different virtual emitter positions. The reconstruction module calculates a low-resolution volumetric image from each beamformed low-resolution image plane. To do this, the reconstruction module determines, for each low-resolution image, at least approximately a constant trajectory of image values, the trajectory intersects the beamformed low-resolution image plane, maps the image coordinates of the image volume to the beamformed low-resolution image plane using the determined trajectory, interpolates the image values at the mapped image coordinates from the image values of the beamformed low-resolution image plane, thereby obtaining a low-resolution volumetric ultrasound image. The combiner module combines the resulting plurality of low-resolution volumetric ultrasound images corresponding to different virtual emitter positions into a combined high-resolution volumetric ultrasound image.

[0050] Console 106 may further include a scan converter 128 and a display 130. The scan converter 128 is configured to scan convert each image for display, for example, by converting the image to the coordinate system of the display 130. Then, a representation of a high-resolution volumetric ultrasound image is displayed, such as a 3D rendering, cross-section, or another type of representation. Instead of or in addition to displaying the generated representation of the high-resolution volumetric ultrasound image, the high-resolution volumetric ultrasound image may be stored and / or further processed, for example, to identify and / or classify the structure or characteristics of the object being imaged.

[0051] Console 106 further includes a user interface 132 that includes one or more input devices (e.g., buttons, touch pads, touch screens, etc.) and one or more output devices (e.g., display screens, speakers, etc.). Console 106 further includes a controller 134 configured to control one or more of the transmission circuit 118, the reception circuit 120, the TX / RX controller 122, the processing pipeline 124, the scan converter 128, the display 130, and / or the user interface 132.

[0052] It will be appreciated that other embodiments of the imaging device may include alternative or additional components, and / or the components may be arranged in different ways, and / or some components may be omitted. For example, the distribution of components between the probe and the console may be different, or the device may include an additional remote data processing system.

[0053] FIG. 2 schematically shows a matrix address - specified transducer array according to the embodiments disclosed in this specification. In particular, FIG. 2 schematically shows an exemplary 6×6 RCA array 202 (N = 6). Each column 204 includes a conductive trace 206 that electrically communicates with each element 208 of the column 204, and the electrode 210 electrically communicates with the conductive trace 206. Each row 212 includes a conductive trace 214 that electrically communicates with the elements 208 of the row 212, and the electrode 216 electrically communicates with the conductive trace 214. The RCA effectively converts a 36 - element 6×6 2D array 202 into a 6 - element 1D column array 218 and an orthogonal 6 - element 1D row array 220. As a result, the number of channels of the elements is substantially reduced from N 2 to 2N.

[0054] Suitable RCA arrays are described in US 10,302,752 and US 10,806,432.

[0055] Furthermore, the conversion elements 208 may include integrated apodization, which may be the same or different for individual elements. An example is described in WO 2015 / 092458. Further, the 2D array 202 may have a flat 1D array, one curved 1D array, two curved 1D arrays, a single curved lens in front of or behind one of the 1D arrays, a double - curved lens in front of or behind the 1D array, a combination of at least one curved 1D array and at least one curved lens, etc. An example is described in WO 2017 / 212313.

[0056] In FIG. 2, each row and each column may have its own front-end circuit. For example, electrode 210 is in electrical communication with its own front-end circuit (not shown), and electrode 216 is in electrical communication with its own front-end circuit (not shown). In a variant, as described in US 10,806,432, a row-column pair can share a front-end circuit. In a shared front-end circuit, both electrodes 210 and 216 are in electrical communication with the same switch (not shown), and the switch switches between electrodes 210 and 216 for transmission and reception. The switch may be part of the shared front-end circuit and / or may be separate from it. This configuration further reduces the number of channels from 2N to N.

[0057] FIGS. 3A and 3B schematically show a coordinate system defined for a matrix-addressable transducer array according to embodiments disclosed herein. As will be appreciated, the rows of the RCA may be used to isonify the volume being imaged, and the columns may be used to receive backscattered signals, or vice versa, i.e., the columns of the RCA may be used to isonify the volume being imaged and the rows may be used to receive backscattered signals. Thus, for simplicity of explanation, it is convenient to introduce a coordinate system with respect to the receiving aperture. Of course, it will be understood that other coordinate systems may be used instead. For the purposes of this specification, the coordinate system is defined such that x’ indicates the axis along which the elements of the receiving array are arranged and y´ indicates the direction of elongation of the individual receiving elements.

[0058] When a (x,y) coordinate system is defined as shown in FIG. 2, that is, when the rows of the array extend along the x-axis and the columns extend along the y-axis, as shown in FIGS. 3A to 3B, it should be noted that when the row aperture receives, (x';y') = (y;x), and when the column aperture receives, (x';y') = (x;y). In particular, FIG. 3A shows the (x',y') coordinate system when the row aperture receives, and FIG. 3B shows the (x',y') coordinate system when the column aperture receives. In either case, the z-direction is the direction extending orthogonally from the plane of the array, that is, the direction orthogonal to the (x',y') plane, and the origin of the coordinate system is defined at the center of the array.

[0059] FIG. 4 schematically shows a non-limiting example of a processing pipeline generally designated 400, implemented by a processing unit 124 of an imaging device disclosed herein, for example the imaging device of FIG. 1. The illustrated processing pipeline 400 receives an RF signal from a receiving circuit 120 as an input and outputs one or more volumetric ultrasonic images.

[0060] The illustrated processing pipeline 400 includes a beamformer module 410. The beamformer module 410 is configured to beamform RF signals onto an image plane and output a series of 2D images, each associated with a respective virtual emitter position. Non-limiting examples of suitable beamforming are described in M. F. Rasmussen, T. L. Christiansen, E. V. Thomsen, and J. A. Jensen, “3-D imaging using row-column-addressed arrays with integrated apodization - Part I: Apodization design and line element beamforming,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., vol. 62, no. 5, pp. 947-958, 2015. Another non-limiting example is described in Stuart et al., “Real-time volumetric synthetic aperture software beamforming of row-column probe data,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., April 8, 2021. Other beamforming approaches are contemplated herein.

[0061] Therefore, the transducer array is controlled to perform ultrasonic emissions corresponding to emissions from a virtual emitter located at the virtual emitter position. For each emission, some or all of the elements of the emission array are controlled to emit an ultrasonic signal with an appropriate phase shift to create an ultrasonic wavefront that appears to originate from the virtual emitter position. The RCA is controlled to perform a series of emissions corresponding to different positions of the virtual emitter, particularly different positions along the y' direction and / or the z direction. For each emission, the elements of the receiving array receive the backscattered signals from the volume that has been isonized, and for each emission, the beamformer module creates a corresponding 2D image associated with the emission, i.e., for each virtual emitter position. For this reason, the beamformer defines an image plane, which may be the same plane or a different plane for each emission. The image plane can be defined parallel to the (x',z) plane at an appropriate position along the y' axis, such as the y' position of the corresponding virtual emitter. For each image point on the image plane, the beamforming module performs beamforming calculations to calculate the image value at the image point. The image points can be distributed as an appropriate raster across the image plane. The spatial density or sampling rate of the image points may be the same or different along the x' direction and the z direction. The beamforming process involves the calculation of the time of flight for each virtual emitter position and for each image point. Using dynamic receive focusing, the beamforming process takes into account the time of flight for moving from the virtual emitter position to the image point and back to the receiving element, particularly directly back along the shortest path, as shown in FIGS. 5A-5C.

[0062] FIGS. 5A-5C are diagrams schematically showing examples of the time of flight paths used in RCA delay-and-sum beamforming according to the embodiments disclosed herein. In particular, FIGS. 5A-5C show the positions of the receiving transducer elements 521 of the receiving array 520, the image points 530, and the virtual emitter 510 as viewed from different directions. FIG. 5A shows a 3D view, FIG. 5B shows a side view along the y' direction, and FIG. 5C shows a top view along the z direction.

[0063] Since the elements of the radiation array extend along the x' direction, as shown in FIGS. 5A to 5AC, the virtual source 510 is a line extending along the x' direction.

[0064] (In the (x', y', z) coordinate system, let the position of the virtual emitter 510 be (x', y v , z v ), and let the position of the image point 530 be

Number

[0065] The total paths from the reference point on the array to the virtual emitter, from the virtual emitter to the image point, and from the image point to the receiving element can be obtained as follows.

Number

Number

[0066] Therefore, the time of flight (ToF) used for RCA delay sum (DAS) beamforming by the beamformer module is

Number

[0067] The diagram of the ToF path in FIG. 5B also shows that the focusing in the zx' plane is similar to that of 2D plane-wave imaging. See, for example, G. Montaldo, M. Tanter, J. Bercoff, N. Benech, and M. Fink, “Coherent plane-wave compounding for very high frame rate ultrasonography and transient elastography,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., vol. 56, pp. 489-506, March 2009. Thus, in the various embodiments described herein, it will be understood that dynamic receive focusing is achieved in the x and z' dimensions. In fact, although there is only one receive element along this direction, dynamic receive focusing is also achieved along the y' axis. To achieve dynamic receive focusing along the y' axis, the various embodiments disclosed herein combine images obtained from different virtual sources located at different positions in the zy' plane. The RCA can change the virtual emitter position in the y'z plane by using apertures with different orientations for transmission and reception, and as shown in FIG. 6, since the virtual emitter position can be changed in this direction, the RCA can resolve objects in height.

[0068] FIG. 6 shows how elements along the y'-axis are effectively synthesized according to various embodiments disclosed herein. FIG. 6 includes two columns of figures. The top figure shows the ToF paths 540 for different positions of the virtual emitter 510 for a fixed image point 530 and a fixed receiving element 521. The bottom figure shows that the radiation at different virtual emitter positions corresponds to the radiation from a fixed virtual emitter position 510, but instead the receiving element 521 is moving along the y'-axis. This shows that moving the radiation source along the y'-axis is substantially the same as receiving the radiation source from different elements along the y'-axis. By combining different radiations, a larger receiving aperture is synthesized, thus providing focusing along the y'-axis. Therefore, this method is sometimes referred to as "synthetic aperture" (SA) imaging.

[0069] Focusing along the y'-axis is further visualized in FIGS. 8A-8C, showing how volumetric image data acquired at different virtual emitter positions are combined to form a high-resolution volumetric ultrasound image. FIGS. 8A-8C show simulated volumetric image data of a point target located at the center of the image volume, in this example (0;0;20) mm. FIGS. 8A-8C show how the point target is resolved from an RCA emission sequence consisting of 22 unique virtual emitter positions. All of the RF data used to construct the beamformed images shown in FIGS. 8A-8C were acquired using 3 MHz 64+64 RCA in a Field II simulation environment (see, e.g., J. A. Jensen, “Field: A program for simulating ultrasound systems,” Med. Biol. Eng. Comp., vol. 10th Nordic-Baltic Conference on Biomedical Imaging, Vol. 4, Supplement 1, Part 1, pp. 351-353, 1996 and J. A. Jensen and N. B. Svendsen, “Calculation of pressure fields from arbitrarily shaped, apodized, and excited ultrasound transducers,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., vol. 39, no. 2, pp. 262-267, 1992).

[0070] Figures 8A and 8B show beam-formed volumetric image data from two emissions with respective virtual emitter positions. The individual volumetric images from the individual emitter positions, all of which cannot individually visualize a point target placed at the center of a volumetric that is resolved in three dimensions, are also called low-resolution volumetric images (LRVs). They resolve the point target as a line rather than a point. Only by combining different LRVs can the point target be accurately represented in all three dimensions, as shown in FIG. 8C, which shows a volumetric image obtained by combining 22 LRVs obtained at respective virtual emitter positions. In FIG. 8C, the imaged point scatterers are resolved at the intersections of the LRV lines. Thus, the combined image, which can spatially resolve the point target in all three dimensions, is also called a high-resolution volumetric image (HRV).

[0071] The inventors realized that each LRV can be created efficiently because the beamforming operation for creating each LRV need not be performed for each image point within the volume being imaged. It is sufficient to perform the beamforming operation only on a representative set of image points, particularly in one image plane. The remaining image values, particularly those outside the image plane, can then be calculated from the image values in the representative set of image points, particularly those within the image plane.

[0072] For example, FIGS. 8A - 8C show that the LRV can only determine the y' position of the point target, and the visualized amplitude is constant along the trajectory in the y'z plane. The trajectory depends on the virtual emitter position, i.e., the trajectories are different for the LRVs shown in FIGS. 8A and 8B. The trajectories from both LRVs intersect at the point target, and since the LRVs coherently combine at this position, the point target can be resolved. The LRV can be viewed as the "backprojection" of the projection of the point target onto the x'z plane, and the volume is resolved by projecting from different angles. However, instead of individually acquiring each image point within the LRV, various embodiments described herein determine the backprojection trajectory and use it to acquire the remaining image points within the volume from the image points of a single x'z plane.

[0073] Accordingly, referring again to FIG. 4, the processing pipeline 400 includes a reconstruction module 420. For each 2D image generated by the beamformer module 410, the reconstruction module determines a set of backprojection trajectories.

[0074] The backprojection trajectory for a given 2D image, i.e., for a given virtual emitter position, is the distance

Number

Number

[0075] This trajectory results in a position within the image volume where the ToF to the closest position of the aperture is constant. This trajectory also corresponds to a position where the entire ToF profile is constant with respect to the active part of the aperture when dynamic receive apodization is used, and is still a good approximation otherwise. z p≧ 0 and (y p ,z p ) ≠ (y v ,z v ) Assuming that, the trajectory can be represented as (x'; y'; z) = (x p ; y'; f(y')), where

Number

Number

[0076] The image values along the trajectory are approximately constant, and as a result, only one point on the path needs to be beamformed. Therefore, according to the above equation, any point within the volume can be mapped to this plane, and the reconstruction module can calculate the image values of the entire 3D LRV image based on the image values of a single beamformed (x'; y p ; z) plane for a given virtual emitter position. The mapping (x', y', z) → (x', y p , f(y p )) Assuming that (y', z) ≠ (y v , z v ), the mapping can be obtained by the following function.

Number

[0077] Since this function does not depend on x', only the mapping of unique (y'; z) coordinates needs to be calculated. Therefore, N x’ N y’ N zAssuming that the volume is beamformed in a 3D grid of size x’ N z it is only necessary to calculate the mapped positions N x’ N y’ N z times. In contrast, in the prior art approach, it is necessary to calculate ToF N

[0078] times. In some embodiments, the position of the image plane along the y'-axis is selected differently for different virtual source positions, and preferably, y p =y v is selected such that the intersection of the trajectories is outside the domain of the trajectories defined by the above inequality, thus avoiding a situation where the intersection of the trajectories is outside the domain of the trajectories defined by the above inequality. However, in some embodiments, for a given point (x', y', z), it can be claimed as follows to determine whether it is on the trajectory defined for y' = y p as well.

Equation

[0079] Another option is to claim that for z < z v we have f(y p ) < z v or for z > z v we have f(y p ) > z v . It should be noted that in some embodiments, since there are several options for avoiding the above conditions, it may not be necessary to claim the above conditions at all. For example, in one embodiment, the process may derive two image planes, one for each solution of the conditional equation (1). Using these two solutions for the image plane, the process may then reconstruct two 3D LRVs. The process may then connect the two LRVs at z = z v . In practice, since z v is far from the imaging region in normal synthetic aperture imaging, it is also possible to not consider the region of f(y').

[0080] In the case of plane wave imaging, the mapping function can be further simplified. The simplified equation can be obtained by first finding the derivative of f(y’). [Number]

[0081] y v and z v are substituted with r sin(Φ) and -r cos(Φ) respectively, and when r→∞, the following is obtained. [Number]

[0082] Here, Φ represents the transmission angle, and the equation indicates that the slope of the trajectory is half of the slope along the transmission wavefront. Therefore, the simplified equation of the trajectory is obtained by the following equation. [Number]

[0083] Furthermore, referring to FIG. 4, the apparatus can then combine volumetric ultrasonic image information from multiple emissions, i.e., for different virtual emitter positions, to obtain a spatially resolved volumetric ultrasonic image, which has high spatial resolution in all three spatial directions and is thus also called a high-resolution volumetric image. For this reason, the processing pipeline further includes a combiner module 430 that receives a series of LRVs calculated by a reconstruction module 420 based on a series of beamformed 2D images generated by a beamformer module 410. The combiner module 430 then weights and sums the image values of the LRVs at each image point optionally, and then combines the LRVs to form a single HRV by performing appropriate normalization optionally.

[0084] In one variation, at least a portion of the processing pipeline 400 is implemented by a computing device separate from the console. In this embodiment, the RF signals stored in memory and / or the beamformed image planes stored in memory can be loaded and processed in the processing pipeline 400 to generate volumetric images as described herein. Such a device can include a scan converter and a display for constructing and visually displaying a representation of the volumetric ultrasound image. Alternatively, or additionally, the volumetric image can be transmitted to the system 102, another ultrasound system, and / or another computer device to construct and visually display a representation of the volumetric ultrasound image or otherwise process the volumetric ultrasound image.

[0085] FIG. 7 shows an exemplary method according to an embodiment of the present specification.

[0086] The following order of acts is for illustrative purposes only and is not limiting. Thus, one or more acts can be performed in a different order, including simultaneously but not limited to this. Further, one or more acts may be omitted and / or one or more other acts may be added.

[0087] In S1, as described herein and / or in other ways, ultrasound is emitted corresponding to the virtual emitter positions.

[0088] In S2, as described herein and / or in other ways, ultrasound signals corresponding to the virtual emitter positions are acquired.

[0089] It will be understood that acts S1 and S2 are optional. For example, in another example, previously acquired and stored images are retrieved from memory.

[0090] In S3, as described herein and / or in other ways, the ultrasound signals are beamformed to generate a 2D image.

[0091] In S4, the remaining 3D image coordinates are mapped onto the plane of the 2D image, and their image values are interpolated to generate a low-resolution volumetric image (LRV) corresponding to the virtual emitter position.

[0092] The actions from S1 to S4 are repeated for different virtual emitter positions. The number of repetitions depends on parameters such as the desired resolution, the desired update frequency, and the size of the RCA.

[0093] Once all the LRVs are generated, the process proceeds to S5, where the LRVs are combined into a single high-resolution volumetric image (HRV) as described herein or by other means.

[0094] In S6, the generated HRV is displayed and / or stored and / or otherwise processed as described herein or by other means. Optionally, image information such as detected objects, dimensions, orientations, volume flows, etc., and / or derived quantities can be estimated and visualized.

[0095] When additional images are generated, the process returns to S1; otherwise, the process may end.

[0096] The above can be implemented by computer-readable instructions encoded or embedded on a memory 126 (i.e., a computer-readable storage medium excluding transient media), which, when executed by a computer processor, cause the processor to perform the actions described herein. Additionally or alternatively, at least one of the computer-readable instructions is carried by a signal, a carrier wave, or other transient media (not a computer-readable storage medium).

[0097] In summary, various embodiments of the proposed RCA beamformer include a beamforming step and a reconstruction step. The beamforming step uses an RCA beamformer known in the art to (x';yp ; z) The image plane is beamformed, and the reconstruction step is interpolation that maps the remaining coordinates to the plane and interpolates the image values thereof. It should be noted that in some embodiments, the z-axis can be sampled at least at the Nyquist frequency to facilitate accurate interpolation in the reconstruction. Alternatively, depending on the interpolation method used, accurate reconstruction may be ensured in another way.

[0098] Since the reconstruction step is independent of the number of channels, beamforming can be performed with a computational complexity of only O(N x’ N y’ N z ), that is, it increases according to the number of image points in the 3D beamforming volume imaged by the volumetric image. On the other hand, the complexity of the prior art approach is O(N x’ N y’ N z N), that is, it increases according to the product of the number of grid points in the 3D beamforming volume and the number of channels in the transducer array. Therefore, the embodiments of the apparatus disclosed herein significantly reduce the computational complexity, especially in the case of a large-scale transducer array. Furthermore, in some embodiments, further reduction of complexity can be achieved as needed. For example, since the trajectory only needs to be calculated for each unique (y'; z) coordinate, the calculated mapping can be stored in memory, and thus it may be possible to eliminate the need to recalculate the mapped positions for each realization of the volume. Alternatively, depending on the computing hardware employed, other optimizations can also be considered, such as using a GPU for the execution of the calculation. Therefore, in some embodiments, dynamic calculation of the mapping can be used instead of storing and reusing the mapping, thereby reducing the memory requirements.

[0099] Finally, various embodiments of the process disclosed herein can recover the volume by storing only the output from the beamforming step and the position information, particularly the output from the virtual emitter position, thus enabling efficient and highly compressed image storage. Example:

[0100] The performance of one embodiment of the proposed RCA beamforming procedure disclosed in this specification was evaluated by wire and cyst phantom measurements using a cyst phantom designed for 3D imaging.

[0101] The measurements were performed by connecting a Vermon 128 + 128 RCA probe to a Verasonics Vantage256 research scanner, and the same transducer and sequence parameters were used in the simulation. The parameters used for these measurements are as follows. · Number of elements: 128 + 128 · Center frequency: 6 MHz · Number of cycles of the transmit pulse: 2 · Speed of sound: 1540 m / s · Element pitch: 0.27 mm · Radiation dose per image: 192 · Pulse repetition frequency: 500 Hz · Transmit and receive apodization: von Hann · Number of active elements: 32 · Transmit and receive F value: -1 / 1 · Sampling frequency: 31.25 MHz.

[0102] For the imaging sequence, 96 unfocused line emissions and 96 unfocused column emissions were used and emitted with a sliding aperture of 32 elements. The transmit and receive F values were set to -1 and 1, and the RF data was acquired at a sampling rate of 31.25 MHz. Finally, beamforming in the (x'; y p ; z) plane was performed at y p = y v . The complete 3D reconstruction from this plane was performed using spline interpolation.

[0103] FIG. 9A shows a 2D slice of a volumetric B-mode image executed by a prior art beamforming method, and FIG. 9B shows a 2D slice of a volumetric B-mode image executed in one embodiment of the beamforming method disclosed herein. FIG. 10A shows a 3D rendering of a volumetric B-mode image executed by a prior art beamforming method, and FIG. 10B shows a 3D rendering of a volumetric B-mode image executed in one embodiment of the beamforming method disclosed herein. As can be seen from FIGS. 9A-9B and FIGS. 10A-10B, the outputs from the two beamformers are not visually distinguishable. The correlation coefficient of the beamformed volume was calculated to be 99.80%.

[0104] The computational complexity of both beamforming methods was evaluated by plotting the average LRV beamforming time from 10 realizations for increasing values of L = N x = N y = N z = N. This means that the number of channels and the number of samples of the side length of the beamformed volume increase simultaneously during the analysis. Also, for the proposed method, N x N y N z it is assumed that the axial sampling rate of the volume is sufficient.

[0105] The prior-art RCA beamforming was performed using a CUDA C / C++ implementation of the RCA beamformer presented in M. B. Stuart, P. M. Jensen, J. T. R. Olsen, A. B. Kristensen, M. Schou, B. Dammann, H. H. B. Sorensen, and J. A. Jensen, “Real-time volumetric synthetic aperture software beamforming of row-column probe data,” IEEE Trans. Ultrason., Ferroelec., Freq. Contr., vol. 68, no. 8, pp. 2608-2618, 2021. The reconstruction step was performed using MATLAB's built-in interpolation function without GPU acceleration. The interpolation method used in the RCA beamformer was cubic interpolation, and the full 3D reconstruction was implemented using spline interpolation as described above. Finally, both the prior art and the proposed method were evaluated on a computer equipped with an NVIDIA Quadro RTX 5000 graphics card and a 2.90 GHz Intel Xeon Gold 6226R CPU.

[0106] Figure 11 shows a comparison of the computation time as a function of the number of samples in the receive aperture and the number of channels. This result assumes that the beamforming step and the reconstruction step contain approximately the same number of samples along the length of the axial side. This assumption is for the N in the final beamformed volume. zis required to be higher than the sampling rate used during the beamforming step. Graph 1101 shows the computation time of a prior art RCA beamformer, and graph 1102 shows the computation time of the method proposed herein. As L increases, the computation time of the prior art RCA beamformer rapidly diverges from the computation time of the proposed RCA beamformer. For example, when L = 64, the computation time of the conventional approach is 12.31 ms, whereas the proposed method achieves beamforming in 2.82 ms. When L = 500, the computation time of the prior art approach is 32:15 seconds, whereas the proposed method performs beamforming in 0.75 seconds. Also, in another more realistic test, the proposed beamformer was able to beamform an LRV of N x N y N z = 192×192×2000 in 0:42 seconds, whereas the prior art beamformer took 3:36 seconds to process the volume.

[0107] At least some embodiments and / or aspects disclosed herein can be summarized as follows. Embodiment 1: An ultrasonic imaging device for providing volumetric ultrasonic images of an image volume, the ultrasonic imaging device comprising a) a matrix addressed transducer array configured to convert an excitation electrical pulse into an ultrasonic pressure field and convert the received ultrasonic echo pressure field into an echo signal; b) a beamformer module configured to beamform the echo signals using dynamic receive focusing to generate respective image values at a first set of image points within the image volume; c) a reconstruction module, determining a set of trajectories, each trajectory intersecting one of the image points of the first set of image points, mapping a second set of image points of the image volume to the first set of image points, Calculate each image value at the mapped image points of the second set of image points from the image values of the image points among the first set of image points. A reconstruction module configured as An ultrasonic imaging apparatus comprising the same. Embodiment 2: The ultrasonic imaging apparatus according to Embodiment 1, comprising a probe and a console operably coupled to the probe, the probe comprising a matrix-addressable transducer array. Embodiment 3: The ultrasonic imaging apparatus according to any one of Embodiments 1 or 2, wherein the matrix-addressable transducer array comprises a first set of transducer elements and a second set of transducer elements, the first set of transducer elements defining a first transducer array arranged along a first axis, and the second set of transducer elements defining a second transducer array arranged along a second axis. Embodiment 4: The ultrasonic imaging apparatus according to Embodiment 3, configured to transmit ultrasonic waves by the first transducer array and receive the ultrasonic waves backscattered by the first or second transducer array. Embodiment 5: The ultrasonic imaging apparatus according to any one of Embodiments 1 to 4, wherein each of the determined trajectories is defined by a position where the flight time from the virtual emitter position to the closest position on one of the receiving-side openings of the first and second transducer arrays is constant along the trajectory. Embodiment 6: The ultrasonic imaging apparatus according to any one of Embodiments 1 to 5, wherein the reconstruction module is configured to map each image coordinate of the image volume to the image points of the first set and store the representation of the mapped image coordinates, and the reconstruction module is configured to calculate a plurality of volumetric images using the stored representation of the mapped image coordinates. Embodiment 7: The ultrasonic imaging apparatus according to any one of Embodiments 1 to 6, wherein the beamformer module is configured to perform delay-and-sum beamforming. Embodiment 8: Using dynamic reception focusing to beamform an echo signal includes, for each image point of a first set of image points, calculating the time of flight along the shortest path from a virtual emitter position to the image point and further from the image point to a reception transducer element of a matrix-addressable transducer array. The ultrasonic imaging device according to any one of Embodiments 1 to 7. Embodiment 9: The ultrasonic imaging device according to any one of Embodiments 1 to 8, wherein the first set of image points defines an image plane of a two-dimensional image within an image volume. Embodiment 10: The ultrasonic imaging device according to Embodiment 9, wherein the image plane extends from a plane defined by a matrix-addressable transducer array, particularly a plane orthogonal to that plane. Embodiment 11: The ultrasonic imaging device according to any one of Embodiments 9 or 10, wherein the image plane is a plane orthogonal to the longitudinal direction of the reception transducer elements of a matrix-addressable transducer array. Embodiment 12: The ultrasonic imaging device is configured to control a matrix-addressable transducer array to perform a plurality of ultrasonic emissions corresponding to ultrasonic waves emitted from respective virtual emitter positions. A beamformer module and a reconstruction module are configured to calculate a plurality of low-resolution volumetric images, each low-resolution volumetric image corresponding to a respective virtual emitter position. The imaging device further comprises an image combiner module configured to combine a plurality of low-resolution volumetric images corresponding to different virtual emitter positions into a combined high-resolution volumetric image having a higher spatial resolution than the low-resolution volumetric images. The ultrasonic imaging device according to any one of Embodiments 1 to 11. Embodiment 13: The beamformer module is configured to beamform echo signals received from a matrix-addressing transducer array in response to emissions so as to generate corresponding plural two-dimensional images, each two-dimensional image corresponding to one of virtual emitter positions, and the reconstruction module is configured to calculate at least a first low-resolution volumetric image among plural low-resolution volumetric images, the first low-resolution image being at least determining a first set of trajectories to a first virtual emitter position, using the first set of trajectories to map the image coordinates of the image volume to the image positions of the first two-dimensional image, interpolating the image values at the mapped image coordinates from the image values of the first two-dimensional image plane, the interpolated image values at the mapped image coordinates representing the first low-resolution volumetric image, The ultrasonic imaging apparatus according to Embodiment 12, corresponding to the first virtual emitter position by the above. Embodiment 14: Receiving an echo signal from a matrix-addressing transducer array, the echo signal representing an ultrasonic echo pressure field received by the matrix-addressing transducer array in response to emitting an ultrasonic pressure field, beamforming the received echo signal using dynamic receive focusing to generate respective image values at a first set of image points in the image volume, determining a set of trajectories, each trajectory intersecting one of the image points of the first set of image points, mapping a second set of image points of the image volume to the first set of image points, calculating respective image values at the mapped image points of the second set of image points from the image values of the image points of the first set of image points and a method including this. Embodiment 15: A computer program that, when executed by a data processing system, includes instructions for causing the data processing system to execute the steps of the method according to Embodiment 14. Embodiment 16: A data processing system configured to execute the steps of the method according to Embodiment 14.

[0108] This application has been described with reference to various embodiments. Upon reading this application, modifications and changes will occur to mind. The present invention is intended to be construed as including all such modifications and changes as long as they are within the scope of the appended claims and their equivalents.

Claims

1. An ultrasonic imaging apparatus for providing volumetric ultrasonic images of an image volume, wherein the ultrasonic imaging apparatus is a) A matrix addressable transducer array configured to convert an excitation electrical pulse into an ultrasonic pressure field and a received ultrasonic echo pressure field into an echo signal, wherein the matrix addressable transducer array comprises a first set of transducer elements and a second set of transducer elements, the first set of transducer elements defining a first transducer array arranged along a first axis, and the second set of transducer elements defining a second transducer array arranged along a second axis, b) A beamformer module configured to beamform the echo signal using dynamic receive focusing in order to generate image values ​​for each of the first set of image points in the image volume, c) Reconfiguration module, Determine a set of trajectories, where each trajectory intersects with one image point from the first set of image points, and each of the determined trajectories is defined according to the virtual emitter position. The image points of the second set of the image volume are mapped to the image points of the first set. From the image values ​​of the image points in the first set, the respective image values ​​of the mapped image points in the second set are calculated. A reconfiguration module, configured in such a way, Equipped with, An ultrasonic imaging apparatus comprising: an ultrasonic imaging apparatus configured to control a matrix addressable transducer array to produce multiple ultrasonic emissions corresponding to ultrasonic waves emitted from each virtual emitter position; a beamformer module and a reconstruction module configured to compute multiple low-resolution volumetric images, each low-resolution volumetric image corresponding to a respective virtual emitter position; and an image combiner module configured to combine multiple low-resolution volumetric images corresponding to different virtual emitter positions into a combined high-resolution volumetric image having a higher spatial resolution than the low-resolution volumetric images.

2. The ultrasonic imaging apparatus according to claim 1, comprising a probe and a console operably coupled to the probe, wherein the probe comprises the matrix addressing transducer array.

3. The ultrasonic imaging apparatus according to claim 1 or 2, further comprising a transmission circuit configured to generate excitation electrical pulses such that the matrix addressing transducer array emits a radiation sequence of ultrasonic pressure fields corresponding to each virtual emitter position.

4. The ultrasonic imaging apparatus according to claim 1 or 2, configured to transmit ultrasonic waves by the first transducer array and to receive backscattered ultrasonic waves by the first or second transducer array.

5. The ultrasonic imaging apparatus according to claim 1 or 2, wherein each of the determined trajectories is defined as a set of positions in the image volume, where the time of flight from the virtual emitter position to the nearest position on one of the receiving apertures of the first and second transducer arrays is constant along the trajectory.

6. The ultrasonic imaging apparatus according to claim 1 or 2, wherein the reconstruction module is configured to map each image coordinate of the image volume to the first set of image points and to store a representation of the mapped image coordinates, and the reconstruction module is configured to compute a plurality of volumetric images using the stored representation of the mapped image coordinates.

7. The ultrasonic imaging apparatus according to claim 1 or 2, wherein the beamformer module is configured to perform delayed sum beamforming.

8. The ultrasonic imaging apparatus according to claim 1 or 2, wherein beamforming the echo signal using dynamic receive focusing includes calculating the time of flight for each image point in the first set of image points along the shortest path from the virtual emitter position to the image point, and further from the image point to the receive transducer element of the matrix addressing transducer array.

9. The ultrasonic imaging apparatus according to claim 1 or 2, wherein the image points of the first set define the image plane of the two-dimensional image in the image volume.

10. The ultrasonic imaging apparatus according to claim 9, wherein the image plane is a plane that extends from a plane defined by the matrix addressing transducer array, particularly orthogonally to that plane.

11. The ultrasonic imaging apparatus according to claim 9, wherein the image plane is a plane orthogonal to the longitudinal direction of the receiving transducer elements of the matrix addressing transducer array.

12. The beamformer module is configured to beamform echo signals received from the matrix addressing transducer array in response to the radiation so as to generate a plurality of corresponding two-dimensional images, each two-dimensional image corresponding to one of the virtual emitter positions, and the reconstruction module is configured to compute at least a first low-resolution volumetric image from the plurality of low-resolution volumetric images, the first low-resolution image being at least Determining a first trajectory set to the first virtual emitter position, Using the first set of orbits, the image coordinates of the image volume are mapped to the image positions of the first two-dimensional image, The method involves interpolating image values ​​in the mapped image coordinates from image values ​​in a first two-dimensional image plane, wherein the interpolated image values ​​in the mapped image coordinates represent the first low-resolution volumetric image. The ultrasonic imaging apparatus according to claim 1 or 2, wherein the first virtual emitter position corresponds to the position of the ultrasonic imaging apparatus according to claim 1 or 2.

13. The ultrasonic imaging apparatus according to claim 1 or 2, wherein the reconstruction module is configured to determine each trajectory in the set of trajectories as a set of positions in the image volume, and the time of flight from a virtual emitter position to the nearest position on one of the receiving apertures of the first and second transducer arrays, via any one of the sets of positions along the trajectory, is constant along the trajectory.

14. A computer implementation method, Receiving an echo signal from a matrix addressable transducer array, wherein the echo signal represents the ultrasonic echo pressure field received by the matrix addressable transducer array in response to the emission of an ultrasonic pressure field. To generate image values ​​for each of the first set of image points in the aforementioned image volume, the received echo signal is beamformed using dynamic receive focusing, Determine a set of trajectories such that each trajectory intersects with one of the image points in the first set of image points, Mapping the image points of the second set of the image volume to the image points of the first set, The process involves calculating the image values ​​of the mapped image points in the second set of image points from the image values ​​of the image points in the first set of image points, Methods that include...

15. A computer program that, when executed by a data processing system, includes instructions causing the data processing system to perform the steps of the method according to claim 14.

16. A data processing system configured to perform the steps of the method according to claim 14.

17. An ultrasonic imaging apparatus for providing volumetric ultrasonic images of an image volume, wherein the ultrasonic imaging apparatus is d) A matrix addressable transducer array configured to convert an excitation electrical pulse into an ultrasonic pressure field and the received ultrasonic echo pressure field into an echo signal, e) A beamformer module configured to beamform the echo signal using dynamic receive focusing in order to generate image values ​​for each of the first set of image points in the image volume, f) A reconfiguration module, Determine a set of trajectories in which each trajectory intersects with one of the image points in the first set of image points. The image points of the second set of the image volume are mapped to the image points of the first set. From the image values ​​of the image points in the first set, the respective image values ​​of the mapped image points in the second set are calculated. A reconfiguration module, configured in such a way, An ultrasonic imaging device equipped with the following features.

18. The ultrasonic imaging apparatus according to claim 17, comprising a probe and a console operably coupled to the probe, wherein the probe comprises the matrix addressing transducer array.

19. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein the matrix addressing transducer array comprises a first set of transducer elements and a second set of transducer elements, the first set of transducer elements define a first transducer array arranged along a first axis, and the second set of transducer elements define a second transducer array arranged along a second axis.

20. The ultrasonic imaging apparatus according to claim 19, configured to transmit ultrasonic waves by the first transducer array and to receive backscattered ultrasonic waves by the first or second transducer array.

21. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein each of the determined trajectories is defined by a position along the trajectory where the time of flight from the virtual emitter position to the nearest position on one of the receiving side apertures of the first and second transducer arrays is constant.

22. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein the reconstruction module is configured to map each image coordinate of the image volume to the first set of image points and to store a representation of the mapped image coordinates, and the reconstruction module is configured to compute a plurality of volumetric images using the stored representation of the mapped image coordinates.

23. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein the beamformer module is configured to perform delayed sum beamforming.

24. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein beamforming the echo signal using dynamic receive focusing includes calculating the time of flight for each image point in the first set of image points along the shortest path from the virtual emitter position to the image point, and further from the image point to the receive transducer element of the matrix addressing transducer array.

25. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein the image points of the first set define the image plane of the two-dimensional image in the image volume.

26. The ultrasonic imaging apparatus according to claim 25, wherein the image plane is a plane that extends from a plane defined by the matrix addressing transducer array, particularly orthogonally to that plane.

27. The ultrasonic imaging apparatus according to claim 25, wherein the image plane is a plane orthogonal to the longitudinal direction of the receiving transducer elements of the matrix addressing transducer array.

28. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein the ultrasonic imaging apparatus is configured to control a matrix addressable transducer array to produce a plurality of ultrasonic emissions corresponding to ultrasonic waves emitted from each virtual emitter position, the beamformer module and the reconstruction module are configured to compute a plurality of low-resolution volumetric images, each low-resolution volumetric image corresponding to a respective virtual emitter position, and the imaging apparatus further comprises an image combiner module configured to combine a plurality of low-resolution volumetric images corresponding to different virtual emitter positions into a combined high-resolution volumetric image having a higher spatial resolution than the low-resolution volumetric images.

29. The beamformer module is configured to beamform echo signals received from the matrix addressing transducer array in response to the radiation so as to generate a plurality of corresponding two-dimensional images, each two-dimensional image corresponding to one of the virtual emitter positions, and the reconstruction module is configured to compute at least a first low-resolution volumetric image from the plurality of low-resolution volumetric images, the first low-resolution image being at least Determining a first trajectory set to the first virtual emitter position, Using the first set of orbits, the image coordinates of the image volume are mapped to the image positions of the first two-dimensional image, The method involves interpolating image values ​​in the mapped image coordinates from image values ​​in a first two-dimensional image plane, wherein the interpolated image values ​​in the mapped image coordinates represent the first low-resolution volumetric image. The ultrasonic imaging apparatus according to claim 28, wherein the first virtual emitter position corresponds to the position of the ultrasonic imaging apparatus according to claim 28.

30. The ultrasonic imaging apparatus according to any one of claims 17 to 18, wherein each of the determined trajectories is defined depending on the virtual emitter position.

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