Systems and methods for ultrasound imaging with a dynamic microbeamformer - Patents.com

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 delay signals, and at least one multi-channel beamformer configured to (i) receive a representation of a plurality of microbeamformed signals and (ii) output at least one representation of the beamformed signal. The plurality of microbeamformed signals may represent a combination of the delay 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 focal points characterizing the microbeamformed signals may be moved along a line of sight.

Description

[Background technology]

[0001]

[0001] Non-invasive imaging systems may be used to image internal tissues, bones, bloodstream, or organs of the human or animal body, or other objects of interest, such as toys or shipping packages. Such systems and / or probes may require the transmission of signals into the body and the reception of signals emitted or reflected from the object or body part being imaged. In some cases, transducers or transceivers may be used to perform imaging, including imaging based on photoacoustic and / or ultrasound effects. Summary of the Invention [Problem to be solved by the invention]

[0002] FIELD OF THE DISCLOSURE

[0002] This disclosure provides systems, devices, and methods for ultrasound imaging, including three-dimensional (3D) imaging based on ultrasound or other sound waves. [Means for solving the problem]

[0003]

[0003] The present disclosure provides an ultrasound imaging system having a multi-stage receive beamformer. A first stage of the multi-stage receive beamformer is a dynamic focusing microbeamformer. The microbeamformer may comprise an array of transducer elements coupled to inputs of a plurality of receive circuits. In some embodiments, the plurality of receive circuit outputs may be coupled to inputs of a plurality of delay circuits, each delay circuit characterized by a time delay value, each providing a delay signal as an output. Optionally, the time delay values ​​characterizing the microbeamforming delay circuits may be controlled such that a focal spot characterizing the microbeamformed signal moves along the line of sight at a propagation speed. In some embodiments, the plurality of delay signals may be weighted and connected to inputs of a plurality of summing amplifiers. In some embodiments, each summing amplifier may provide as an output a microbeamformed signal representing a combination of the delay signals. In some embodiments, a plurality of representations of the plurality of microbeamformed signals may be coupled to inputs of a second stage multi-channel beamformer, which provides as an output a beamformed signal.

[0004]

[0004] In some preferred embodiments, the microbeamforming ultrasound imaging system disclosed herein can be configured to control the time delay values ​​used to form the microbeamformed signal such that the focal spot characterizing the microbeamformed signal moves substantially along the line of sight at an expected propagation speed. This control of the time delay values ​​can help optimize image quality. In some embodiments, the time delay values ​​used in the multi-channel beamformer can be controlled such that the focal spot of the fully beamformed output signal moves substantially along the line of sight. This control of the time delay values ​​in the microbeamformer can provide significant benefits over conventional systems, where the time delay values ​​used are selected or set prior to transmission of the ultrasound pulse (e.g., to represent the expected difference in arrival times between elements in a group for echoes received from a single focal spot at a given steering angle and distance) and remain fixed while the received signal is being observed. Unlike conventional microbeamformers that can only focus at one point in time (corresponding to a single focal spot), the system disclosed herein can allow the focal spot to move along the line of sight.

[0005]

[0005] In one aspect, 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.

[0006] In some embodiments, the plurality of receive circuits comprises at least one input coupled to at least one transducer element of the array of transducer elements. In some embodiments, the plurality of delay circuits comprises one or more inputs coupled to at least one receive circuit of the plurality of receive circuits. In some embodiments, the plurality of delay circuits are characterized by a plurality of time delay values. In some embodiments, the plurality of time delay values ​​are controllable or adjustable such that one or more focal points characterizing the microbeamformed signal move along the line of sight. In some embodiments, the plurality of microbeamformed signals represent a combination of delay signals from the plurality of delay circuits.

[0007]

[0007] In some embodiments, at least one of the plurality of receive circuits comprises a time gain compensation circuit. In some embodiments, at least one of the plurality of delay circuits comprises an analog sample and hold delay circuit. In some embodiments, at least one of the plurality of delay circuits comprises an analog delay circuit. In some embodiments, the multi-channel beamformer comprises an analog multi-channel beamformer. In some embodiments, at least one of the plurality of delay circuits comprises an analog delay circuit. In some embodiments, the multi-channel beamformer comprises a digital multi-channel beamformer. In some embodiments, at least one of the plurality of delay circuits comprises a digital delay circuit. In some embodiments, the multi-channel beamformer comprises a digital multi-channel beamformer.

[0008] In some embodiments, the array of transducer elements comprises a one-dimensional array. In some embodiments, the array of transducer elements comprises a two-dimensional array. In some embodiments, the transducer elements comprise one or more PMUT elements. In some embodiments, the transducer elements comprise one or more CMUT elements.

[0009] In some embodiments, the focal point characterizing the microbeamformed signal moves substantially along a line of sight at a speed that is about half the propagation speed of the ultrasound signal in the material being imaged, hi some embodiments, the line of sight corresponds to at least a portion of the imaging path or imaging region of interest.

[0010]

[0010] In another aspect, the present disclosure provides an ultrasound imaging system comprising an array of transducer elements, a plurality of receiving circuits configured to provide one or more output signals, a plurality of delay circuits configured to output one or more delay signals, a plurality of delay calculation circuits configured to control or adjust one or more time delay values ​​characterizing the plurality of delay circuits, 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 the beamformed signal.

[0011] In some embodiments, each of the plurality of receive circuits comprises at least one input coupled to at least one transducer element of the array of transducer elements. In some embodiments, the plurality of delay circuits comprises one or more inputs coupled to at least one receive circuit of the plurality of receive circuits. In some embodiments, the plurality of microbeamformed signals represent a combination of delayed signals from the plurality of delay circuits.

[0012] In some embodiments, the plurality of delay calculation circuits are configured to control or adjust one or more time delay values ​​such that one or more focal points characterizing the microbeamformed signal move along the line of sight at a propagation speed. In some embodiments, at least one delay calculation circuit of the plurality of delay calculation circuits is configured to calculate the at least one time delay value by adding at least one constant term and at least one exponential decay term. In some embodiments, at least one delay calculation circuit of the plurality of delay calculation circuits is configured to calculate the one or more time delay values ​​using a linear interpolation algorithm. In some embodiments, at least one delay calculation circuit of the plurality of delay calculation circuits is configured to calculate the one or more time delay values ​​using a Coordinate Rotation Digital Computation (CORDIC) algorithm.

[0013]

[0013] In some embodiments, at least one receive circuit of the plurality of receive circuits comprises a time gain compensation circuit. In some embodiments, at least one delay circuit of the plurality of delay circuits comprises an analog sample and hold delay circuit. In some embodiments, at least one delay circuit of the plurality of delay circuits comprises an analog delay circuit. In some embodiments, the multi-channel beamformer comprises an analog multi-channel beamformer. In some embodiments, at least one delay circuit of the plurality of delay circuits comprises an analog delay circuit. In some embodiments, the multi-channel beamformer comprises a digital multi-channel beamformer. In some embodiments, at least one delay circuit of the plurality of delay circuits comprises a digital delay circuit. In some embodiments, the multi-channel beamformer comprises a digital multi-channel beamformer.

[0014] In some embodiments, the array of transducer elements comprises a one-dimensional array. In some embodiments, the array of transducer elements comprises a two-dimensional array. In some embodiments, the array of transducer elements comprises a two-dimensional array on a curved surface. In some embodiments, the transducer elements comprise one or more PMUT elements. In some embodiments, the transducer elements comprise one or more CMUT elements. In some embodiments, the transducer elements, the receive circuitry, the delay circuitry, and the delay computation circuitry are configured or physically arranged to have at least one common pitch in at least one dimension.

[0015] In some embodiments, the system may further comprise one or more converters, hi some embodiments, the one or more converters comprise an analog-to-digital converter.

[0016]

[0016] In another aspect, the present disclosure provides a method including: (a) receiving one or more signals for ultrasound imaging of a target region; (b) generating one or more delayed signals based on (i) the one or more signals for ultrasound imaging and (ii) one or more time delay values; (c) aggregating the one or more delayed signals to form a plurality of microbeamformed signals; and (d) combining the plurality of microbeamformed signals using a multi-channel beamformer to create the beamformed signal. In some embodiments, the one or more time delay values ​​are adjustable to move one or more focal points characterizing the microbeamformed signals along a line of sight that spans at least a portion of the target region.

[0017] In some embodiments, one or more delayed signals are summed by one or more summing amplifiers to form multiple microbeamformed signals.

[0018] In some embodiments, the method may further include, after (c), providing the plurality of microbeamformed signals to one or more converters. In some embodiments, the one or more converters comprise analog-to-digital converters. In some embodiments, the one or more converters are configured to provide digital representations of the microbeamformed signals. In some embodiments, the multi-channel beamformer is configured to aggregate the digital representations of the microbeamformed signals to provide a digital representation of the beamformed signal.

[0018]

[0019] In some embodiments, the multi-channel beamformer is configured to delay and combine multiple microbeamformed signals to create a beamformed signal. In some embodiments, the one or more time delay values ​​are adjusted using multiple delay calculation circuits. In some embodiments, the delayed signal is generated using one or more delay circuits. In some embodiments, the one or more delay circuits comprise analog delay circuits. In some embodiments, the one or more delay circuits comprise digital delay circuits.

[0019]

[0020] In some embodiments, one or more signals for ultrasound imaging are received from (i) an array of transducer elements, or (ii) one or more receive circuits operably coupled to the array of transducer elements. In some embodiments, the array of transducer elements comprises one or more PMUT elements. In some embodiments, the array of transducer elements comprises one or more CMUT elements. In some embodiments, the array of transducer elements comprises a one-dimensional array. In some embodiments, the array of transducer elements comprises a two-dimensional array.

[0020]

[0021] In some embodiments, the focal point characterizing the microbeamformed signal moves along a line of sight at a speed that is about half the propagation speed of the ultrasound signal in the material being imaged, hi some embodiments, the line of sight corresponds to at least a portion of the imaging path or imaging region of interest.

[0021]

[0022] Another aspect of the present disclosure provides a non-transitory computer-readable medium containing machine-executable code that, when executed by one or more computer processors, implements any of the methods described above or elsewhere herein.

[0022]

[0023] Another aspect of the present disclosure provides a system comprising one or more computer processors and a computer memory coupled thereto, the computer memory including machine executable code that, when executed by the one or more computer processors, implements any of the methods described above or elsewhere herein.

[0023]

[0024] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, in which exemplary embodiments of the present disclosure are shown and described. As will be understood, the present disclosure is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the present disclosure. Thus, the drawings and description should be regarded as illustrative in nature, and not restrictive. Incorporation by Reference

[0025] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

[0024]

[0026] A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description and accompanying drawings that set forth illustrative embodiments. [Brief description of the drawings]

[0025] [Figure 1]

[0027] FIG. 1 is a block diagram of a microbeamforming ultrasound imaging system, according to some embodiments. [Diagram 2]

[0028] 1 is a schematic diagram of the expected time of flight between one or more targets and one or more ultrasonic transducer elements. [Diagram 3]

[0029] FIG. 1 illustrates an example implementation of an analog sample and hold delay circuit. [Figure 4]

[0030] FIG. 2 illustrates an implementation of a delay calculation circuit, according to some embodiments. [Diagram 5]

[0031] 1 is an exemplary schematic diagram of an ultrasound imaging system, in accordance with some embodiments. [Figure 6]

[0032] 1 is an exemplary block diagram of an ultrasound imaging system, in accordance with some embodiments. [Figure 7]

[0033] 2 is another exemplary schematic diagram of an ultrasound imaging system, in accordance with some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026]

[0034] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and substitutions will occur to those skilled in the art without departing from the invention. It will be understood that various alternatives to the embodiments of the invention described herein may be employed.

[0027]

[0035] Specific Definitions

[0036] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter belongs.

[0028]

[0037] As used herein, in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Any reference to "or" herein is intended to also include "and / or" unless specifically stated otherwise.

[0029]

[0038] As used herein, the term "about" refers to an amount closer to the recited amount by about 10%, 5%, or 1%, including increments therebetween.

[0039] Whenever the terms "at least," "greater than," or "greater than or equal to" precede a first number in a series of two or more numbers, the terms "at least," "greater than," or "greater than or equal to" apply to every number in the series. For example, 1, 2, or 3 or more is equivalent to 1 or more, 2 or more, or 3 or more.

[0030]

[0040] Whenever the terms "no more than," "less than," or "less than or equal to" precede a first number in a series of two or more numbers, the terms "no more than," "less than," or "less than or equal to" apply to every number in the series. For example, 3, 2, or 1 or less is equivalent to 3 or less, 2 or less, or 1 or less.

[0031]

[0041] The terms "real time" or "real-time," as used interchangeably herein, generally refer to events (e.g., operations, processes, methods, techniques, computations, calculations, analyses, visualizations, optimizations, etc.) that are performed using recently obtained (e.g., collected or received) data. In some cases, real-time events can be performed nearly instantaneously or within a sufficiently short period of time, such as within a period of at least 0.0001 milliseconds (ms), 0.0005 ms, 0.001 ms, 0.005 ms, 0.01 ms, 0.05 ms, 0.1 ms, 0.5 ms, 1 ms, 5 ms, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 1 second, or more. In some cases, real-time events may occur nearly instantly or within a sufficiently short period of time, such as within a period of at most 1 second, 0.5 seconds, 0.1 seconds, 0.05 seconds, 0.01 seconds, 5 ms, 1 ms, 0.5 ms, 0.1 ms, 0.05 ms, 0.01 ms, 0.005 ms, 0.001 ms, 0.0005 ms, 0.0001 ms, or less.

[0032]

[0042] Ultrasound Imaging

[0043] The present disclosure provides systems and methods for ultrasound imaging, which can involve transmitting ultrasound pulses and receiving reflected signals at an array of transducer elements.

[0033]

[0044] In one aspect, the present disclosure provides an ultrasound imaging system, more particularly an electronically guided and focused ultrasound imaging system, hi another aspect, the present disclosure provides an ultrasound imaging system with improved control of guidance and focusing.

[0034]

[0045] In some embodiments, an ultrasound imaging system can include an array of transducer elements. In some cases, the system can transmit ultrasound pulses from the transducer array and receive the resulting reflected ultrasound energy by observing the output of the transducer elements over time. The elapsed time from transmission to reception can represent the distance from the transducer element to a desired focal point. In some embodiments, an ultrasound imaging system can include a receiver that can combine the output of the transducer elements into one or more beamformed or microbeamformed signals.

[0035]

[0046] In one aspect, the present disclosure provides a system for ultrasound imaging. The system may include an array of transducer elements. In some cases, the system may include a plurality of receiver circuits configured to provide one or more output signals. In some embodiments, the plurality of receiver circuits may include at least one input coupled to at least one transducer element of the array of transducer elements.

[0036]

[0047] Optionally, the system may include a plurality of delay circuits configured to output one or more delayed signals. Optionally, the plurality of delay circuits may include one or more inputs coupled to at least one of the plurality of receiving circuits. Optionally, the plurality of delay circuits may be characterized by a plurality of time delay values.

[0037]

[0048] Optionally, the system may comprise at least one multi-channel beamformer configured to (i) receive a representation of a plurality of microbeamformed signals and (ii) output at least one representation of the beamformed signal. Optionally, the plurality of microbeamformed signals may represent a combination of delayed signals from a plurality of delay circuits. In some embodiments, the plurality of time delay values ​​may be controllable or adjustable such that one or more focal points characterizing the microbeamformed signal may be moved along the line of sight.

[0038]

[0049] Transducer Array

[0050] In some embodiments, the system can include a transducer array. The transducer array can include a number of elements for transmitting and / or receiving waves, signals, or pulses. The waves, signals, or pulses can include ultrasound waves, signals, or pulses.

[0039]

[0051] In some embodiments, the ultrasound imaging system can include an array of transducer elements. The transducer elements can be piezoelectric transducers (PZT), piezoelectric micromechanical ultrasound transducers (PMUT), or capacitive micromechanical ultrasound transducers (CMUT). In some cases, the transducer elements can comprise one or more PMUT elements and / or one or more CMUT elements.

[0040]

[0052] The array of transducer elements may constitute a one-dimensional (1D) array or a two-dimensional (2D) array, in some embodiments, the 2D array may constitute a 2D array on a curved surface.

[0041]

[0053] In some embodiments, the array of transducer elements may be physically arranged in rows and / or columns in a repeating arrangement, such as a rectangular or hexagonal grid, Optionally, the array of transducer elements may include at least one common pitch that describes the physical spacing between elements in at least one dimension.

[0042]

[0054] Receiving circuit

[0055] In some embodiments, the system may include one or more receiver circuits. The multiple receiver circuits may include at least one input coupled to at least one transducer element of the array of transducer elements. The multiple receiver circuits may be configured to generate or create one or more output signals. The one or more output signals may correspond to one or more signals, waves, or pulses transmitted or received by the transducer array or any one or more elements thereof.

[0043]

[0056] In some embodiments, the ultrasound imaging system can include a receiver circuit having at least one input coupled to the transducer elements and providing at least one output. In some cases, the receiver circuit can provide one or more analog signals or one or more digital signals as an output.

[0044]

[0057] In some cases, the receiving circuit may comprise a switch, an amplifier, a sample-and-hold circuit, an attenuator, a time-gain compensation (TGC) circuit, an ADC, and / or digital logic. The amplifier may comprise, for example, a low-noise amplifier (LNA), a variable-gain amplifier (VGA), a fixed-gain amplifier, a summing amplifier, a single-ended amplifier, or a differential amplifier. In some cases, at least one of the receiving circuits may comprise a time-gain compensation circuit. The time-gain compensation (TGC) circuit may be configured to receive a signal as an input and may provide an output that substantially represents the input multiplied by a TGC gain. In some embodiments, the TGC gain may be controlled to change over time. In some cases, the TGC gain may be greater than or equal to 1 (amplification) or less than or equal to 1 (attenuation). In some cases, the TGC circuit may comprise a variable-gain amplifier (VGA), a fixed-gain amplifier, an attenuator, a resistor, or a capacitor. In some embodiments, the ultrasound imaging system may comprise a TGC circuit having a TGC gain that may be controlled to compensate for expected changes in the amplitude of the received ultrasound signal over time.

[0045]

[0058] Delay Circuit

[0059] In some embodiments, the system may include a plurality of delay circuits. The plurality of delay circuits may include one or more inputs coupled to at least one receiver circuit of the plurality of receiver circuits. The plurality of delay circuits may be configured to output one or more delayed signals. The delayed signals may correspond to one or more output signals received from the plurality of receiver circuits. The delayed signals may include at least one signal to which a time delay has been applied. The at least one signal may include one or more output signals received from the plurality of receiver circuits. In some cases, the plurality of delay circuits may be characterized by a plurality of time delay values. The time delay values ​​may be dynamically adjustable.

[0046]

[0060] Optionally, at least one of the plurality of delay circuits comprises an analog sample and hold delay circuit. Optionally, at least one of the plurality of delay circuits can comprise an analog delay circuit (e.g., when a multi-channel beamformer comprising an analog multi-channel beamformer is used). Optionally, at least one of the plurality of delay circuits can comprise an analog delay circuit (e.g., when a multi-channel beamformer comprising a digital multi-channel beamformer is used). Optionally, at least one of the plurality of delay circuits can comprise a digital delay circuit (e.g., when a multi-channel beamformer comprising a digital multi-channel beamformer is used).

[0047]

[0061] In some embodiments, the system may include one or more delay circuits. The one or more delay circuits may have at least one input and may provide a time delay value (T DELAY Optionally, one or more delay circuits may provide at least one delayed signal as an output, such that at time (t), the delayed signal substantially represents an earlier time input (tT DELAY ).

[0048]

[0062] In some embodiments, the delay circuit may be an analog delay circuit that receives an analog signal as an input and provides an analog signal as an output. The analog delay circuit may be implemented using a sample and hold circuit, such as the circuit shown in Figure 3. In some cases, the sample and hold delay circuit may store a value representing the input signal on one or more capacitors and use these capacitors to provide a delayed signal as an output.

[0049]

[0063] In some embodiments, the analog signals provided as outputs from the analog delay circuits may be combined by connecting capacitors together, which may have the effect of adding or averaging the values ​​stored on the capacitors. In some cases, the analog signals provided as outputs from the delay circuits may be combined by coupling them to the inputs of a summing amplifier circuit. The summing amplifier circuit may comprise a resistor or capacitor coupled to the amplifier input or output.

[0050]

[0064] In some embodiments, the delay circuit may comprise a digital delay circuit that receives a digital signal as an input and provides a digital signal as an output. The digital delay circuit may comprise a first-in, first-out buffer (FIFO) having an input address specified by a write pointer value and an output address specified by a read pointer value. Both the read and write pointer values ​​may be controlled to increment at a predetermined rate. In some cases, the delay value of the digital delay circuit may be adjusted by controlling the difference between the read and write pointer values.

[0051]

[0065] In some embodiments, the digital delay circuit may comprise a multi-bit parallel shift register and a multiplexer. An input of the shift register may be coupled to a digital input signal of the digital delay circuit. Optionally, a data input of the multiplexer may be coupled to the contents of the shift register. An output of the multiplexer may provide a delayed digital signal at the output of the digital delay circuit. In some embodiments, the delay value of the digital delay circuit may be controlled by selecting the input of the multiplexer.

[0052]

[0066] In some cases, the digital delay circuits may comprise flip-flops, latches, or random access memory (RAM) circuits. In some cases, the digital signals provided as outputs from the digital delay circuits may be combined by adding together representations of the digital signals, thereby producing the effect of adding or averaging the values ​​represented by the digital signals.

[0053]

[0067] Time Delay Value

[0068] In some preferred embodiments, the microbeamforming ultrasound imaging system disclosed herein can be configured to control the time delay values ​​used to form the microbeamformed signals such that the focal spot characterizing the microbeamformed signals moves substantially along the line of sight at the expected propagation speed. This control of the time delay values ​​can help optimize image quality. In some embodiments, the time delay values ​​used in the multi-channel beamformer can be controlled such that the focal spot of the fully beamformed output signal moves substantially along the line of sight. This control of the time delay values ​​can provide a significant advantage over conventional systems, where the time delay values ​​used are selected or set prior to transmission of the ultrasound pulse (e.g., to represent the expected difference in arrival times between elements in a group for echoes received from a single focal spot at a given steering angle and distance) and are maintained fixed while the received signals are observed. Unlike many conventional systems that can only focus at one point in time (corresponding to a single focal spot), the systems disclosed herein allow the focal spot to move along the line of sight.

[0054]

[0069] In some cases, it may be desirable to delay signals received at transducer elements in a transducer array and combine the delayed signals together to create one or more steered and focused beamformed signals. The time delay values ​​may be selected to compensate for differences in expected arrival times to various elements in the transducer array. In some cases, the delayed signals may be weighted equally or differently when combined. In some cases, the delayed signals may be combined by adding them together (delay-sum) or averaging them to create one or more beamformed signals.

[0055]

[0070] Focus / Line of Sight

[0071] As discussed above, in some embodiments, the multiple time delay values ​​may be controllable or adjustable such that one or more focal points characterizing the microbeamformed signal move along the line of sight. In some embodiments, the focal points characterizing the microbeamformed signal may move along the line of sight at a speed that is approximately one-half the propagation speed of the ultrasound signal in the material being imaged.

[0056]

[0072] In some embodiments, the line of sight can correspond to at least a portion of an imaging path or imaging region of interest. The imaging path can correspond to a scan pattern or scan direction. In some cases, the scan pattern can be defined or associated with a specific imaging location or region or field of view. In some cases, the scan direction can correspond to an imaging vector (i.e., a vector or a series of vectors that define a path along which imaging can be performed). In some cases, the line of sight can be associated with an imaging line. In some cases, the imaging line can correspond to a column or row or other linear or non-linear series of pixels in an image. In some cases, the imaging line (also referred to herein as a scan line) can correspond to at least a portion of the imaging vector along which imaging is performed.

[0057]

[0073] In some embodiments, the line of sight can correspond to a scan line of an image. As used herein, a scan line can correspond to or represent a portion of a frame representing an image. To form a frame, a transducer can focus and / or transmit waves (e.g., acoustic or pressure waves) from different piezoelectric elements to a particular focal point. Reflected signals collected by these piezoelectric elements can be received, delayed, weighted, and summed to form a scan line. The focus of interest can be changed to a different portion of the frame, and this process can be repeated until an entire frame containing multiple scan lines is generated.

[0058]

[0074] In some embodiments, the line of sight can correspond to an imaging path of an ultrasound imaging system. The imaging path can cover a target location or area of ​​interest or a field of view. The imaging path can include one or more imaging vectors (i.e., a vector or a series of vectors that define a path along which imaging can be performed). The imaging path can include one or more linear portions and / or one or more curved portions.

[0059]

[0075] In some embodiments, the line of sight can be selected to occur at the center of the transducer array. In other embodiments, the line of sight can be selected to occur inside or outside the transducer array, behind the transducer array, or at another point in front of the transducer array. In some cases, the line of sight can be bent straight ahead (e.g., in a direction orthogonal to the transducer array). In other cases, the line of sight can be bent away from the orthogonal direction in one or more dimensions.

[0060]

[0076] Propagation Velocity

[0077] 2, at a given time, the value of the beamformed signal may represent an ultrasound signal reflected from a target at a focal point, such as focal point 39 or 42. This focal point 39 or 42 may change over time and may move substantially along line of sight 43 at a propagation speed. This propagation speed may be approximately one-half the propagation speed of the ultrasound signal in the material being imaged. For example, in human tissue, the focal point may move along line of sight at approximately 770 meters per second.

[0061]

[0078] In some cases, the ultrasonic signal reflected from a target located at the desired focal point may arrive at each transducer element at different times, as shown in Figure 2. This difference in arrival time may be determined by the propagation speed of the ultrasonic signal, the location of the element within the transducer array, and / or the angle and distance to the desired focal point.

[0062]

[0079] Delay Calculator

[0080] In some embodiments, the ultrasound imaging system may include one or more delay calculators. The delay calculator may be implemented in hardware (e.g., as a delay calculation circuit) or in software. In some embodiments, the delay calculation circuit may include an adder or a multiplier. In some embodiments, the delay calculation circuit may use a coordinate rotation digital calculation (CORDIC) algorithm. As used herein, the CORDIC algorithm may comprise an algorithm that calculates trigonometric functions, hyperbolic functions, square roots, multiplication, division, and exponents and logarithms with any base, typically converging to one digit (or bit) per iteration. The CORDIC algorithm may be used in cases where hardware multipliers are not available (e.g., in simple microcontrollers and FPGAs) because the only operations required are addition, subtraction, bit shifting, and lookup tables.

[0063]

[0081] Optionally, the delay calculator can be used to calculate one or more expected times of flight from the focal point to a location. Optionally, the delay calculator can be used to calculate one or more expected differences in the times of flight from the focal point to multiple locations. Optionally, the delay calculator can be used to control one or more time delay values ​​that characterize one or more delay circuits, as described elsewhere herein. Optionally, the delay calculator can be used to control the time delay values ​​such that the focal point of the beamformed signal and / or microbeamformed signal moves substantially along the line of sight at the propagation speed.

[0064]

[0082] In some embodiments, the delay calculation circuitry can calculate the time of flight between two points based on the distance between the points in two dimensions (X, Y) or three dimensions (X, Y, Z). The time of flight is calculated based on the number X 2 +Y 2 +Z 2 can be proportional to the square root of

[0065]

[0083] In some embodiments, the delay calculation circuitry can use interpolation to approximate the time of flight or the difference in the time of flight. In some cases, the delay calculator can use interpolation across time, physical space, beam origin, or beam angle. The delay calculator can use linear or non-linear interpolation. In some cases, the delay calculation circuitry can calculate a sum of a constant term and an exponential decay term to perform a non-linear interpolation across time.

[0066]

[0084] In some cases, at least some of the receiving circuits, delay circuits, or delay calculation circuits described herein can be located physically separate from the transducer array or can be arranged in a different configuration than the transducer array. In some cases, at least some of these circuits can be located adjacent to or proximate to the transducer array and can be physically arranged to have at least one pitch in common with the transducer array, which can help reduce size, cost, and power requirements.

[0067]

[0085] Converter

[0086] In some embodiments, the ultrasound imaging system may include one or more analog-to-digital converter (ADC) circuits that may be configured to receive at least one analog signal as an input and provide at least one digital representation of the input as an output. Optionally, the one or more ADC circuits may be implemented as a successive approximation ADC, a pipeline ADC, a sigma-delta ADC, a flash ADC, a Nyquist ADC, or an oversampling ADC. Optionally, the ultrasound imaging system may include an ADC that receives an analog microbeamformed signal as an input and provides a digital representation of the microbeamformed signal as an output.

[0068]

[0087] Beamforming

[0088] The ultrasound imaging systems disclosed herein can be configured to combine information from multiple signals (e.g., raw signals and / or beamformed signals) to form images that represent ultrasound signals reflected from a range of locations. The images can be 1D, 2D, or 3D pictures or videos, or can take the form of charts or graphs. The images can be monochrome (black and white) or color images. The images can represent human tissue or other materials. The images can include information regarding density, size, velocity, or flow rate. The images can represent magnitude, phase, harmonic content, or other characteristics of the received ultrasound signals.

[0069]

[0089] The ultrasound imaging systems described herein may perform or implement a beamforming delay-and-sum operation in multiple steps (e.g., by using a microbeamforming ultrasound system) to reduce (1) the size / footprint of the imaging system, (2) the cost of the imaging system, and / or (3) the power requirements of the imaging system. A block diagram of a microbeamforming ultrasound imaging system in accordance with the present disclosure is shown in FIG.

[0070]

[0090] In some cases, the system may first delay and combine multiple signals from one or more groups of elements (e.g., localized elements) into a smaller number of microbeamformed signals. The microbeamformed signals may be provided as inputs to a multi-channel beamformer, which may delay and combine the microbeamformed signals to form one or more fully beamformed signals, for example using further delay-and-sum operations. Such a multi-channel beamformer may be configured to delay each microbeamformed signal to compensate for differences in expected arrival times for each group of elements represented by each microbeamformed signal. The delays may create beamformed signals that may be steered and / or focused to a given focal point at a given time.

[0071]

[0091] In some embodiments, the ultrasound imaging system may include a multi-channel beamformer capable of receiving as an input a representation of a plurality of microbeamformed signals and capable of providing as an output at least one representation of a beamformed signal. The plurality of microbeamformed signals may represent a combination of signals from a plurality of delay circuits.

[0072]

[0092] In some cases, the multi-channel beamformer may comprise an analog multi-channel beamformer that receives an analog signal as an input and provides at least one analog signal as an output. In some cases, the multi-channel beamformer may comprise a digital multi-channel beamformer that receives a digital signal as an input and provides at least one digital signal as an output. The digital multi-channel beamformer may comprise memory elements and digital circuits implemented in an integrated circuit or programmable logic device such as a field programmable gate array (FPGA). The digital multi-channel beamformer may comprise a microprocessor or microcontroller. The digital multi-channel beamformer may be implemented in hardware or software.

[0073]

[0093] Additional Embodiments

[0094] In another aspect, the present disclosure provides an ultrasound imaging system. The ultrasound imaging system may include an array of transducer elements. In some cases, the array of transducer elements may constitute a one-dimensional array. In some cases, the array of transducer elements may constitute a two-dimensional array, such as a two-dimensional array on a curved surface. In some cases, the transducer elements may constitute one or more PMUT elements. In some cases, the transducer elements may constitute one or more CMUT elements.

[0074]

[0095] In some embodiments, the imaging system may include a plurality of receiver circuits configured to provide one or more output signals. Optionally, each of the plurality of receiver circuits may include at least one input coupled to at least one transducer element of the array of transducer elements. Optionally, at least one receiver circuit of the plurality of receiver circuits may comprise a time gain compensation circuit.

[0075]

[0096] In some embodiments, the system may include a plurality of delay circuits configured to output one or more delayed signals. Optionally, the plurality of delay circuits may include one or more inputs coupled to at least one of the plurality of receiving circuits.

[0076]

[0097] In some cases, at least one delay circuit of the plurality of delay circuits may comprise an analog sample and hold delay circuit. In some cases, at least one delay circuit of the plurality of delay circuits may comprise an analog delay circuit, for example, in some cases a multi-channel beamformer that comprises an analog multi-channel beamformer is used, or in other cases a multi-channel beamformer that comprises a digital multi-channel beamformer is used. In some cases, at least one delay circuit of the plurality of delay circuits may comprise a digital delay circuit (for example, when a multi-channel beamformer that comprises a digital multi-channel beamformer is used).

[0077]

[0098] In some embodiments, the system may comprise a plurality of delay calculation circuits configured to control or adjust one or more time delay values ​​characterizing the plurality of delay circuits. Optionally, the plurality of delay calculation circuits may be configured to control or adjust one or more time delay values ​​such that one or more focal points characterizing the microbeamformed signal move along the line of sight at a propagation speed. Optionally, at least one delay calculation circuit of the plurality of delay calculation circuits may be configured to calculate the at least one time delay value by adding at least one constant term and at least one exponential decay term. Optionally, at least one delay calculation circuit of the plurality of delay calculation circuits may be configured to calculate the one or more time delay values ​​using a linear interpolation algorithm. Optionally, at least one delay calculation circuit of the plurality of delay calculation circuits may be configured to calculate the one or more time delay values ​​using a Coordinate Rotation Digital Computation (CORDIC) algorithm.

[0078]

[0099] In some embodiments, the system may comprise at least one multi-channel beamformer configured to (i) receive a representation of a plurality of microbeamformed signals, and (ii) output at least one representation of the beamformed signal. In some cases, the plurality of microbeamformed signals may represent a combination of delayed signals from a plurality of delay circuits.

[0079]

[0100] Optionally, the imaging system may further comprise one or more converters, which may comprise, for example, an analog-to-digital converter.

[0080]

[0101] In any of the embodiments described herein, the transducer elements, the receiving circuitry, the delay circuitry, and the delay calculation circuitry may be configured or physically arranged to have at least one common pitch in at least one dimension.

[0081]

[0102] Imaging method

[0103] In another aspect, the present disclosure provides a method of imaging, which may include (a) receiving one or more signals for ultrasound imaging of a target region.

[0082]

[0104] In some embodiments, the method can include (b) generating one or more delayed signals based on (i) one or more signals for ultrasound imaging and (ii) one or more time delay values. Optionally, the one or more time delay values ​​can be adjustable to move one or more focal points characterizing the microbeamformed signals along a line of sight that spans at least a portion of the target region.

[0083]

[0105] In some embodiments, the method may include (c) aggregating one or more delayed signals to form a plurality of microbeamformed signals. In some embodiments, the method may include (d) combining the plurality of microbeamformed signals using a multi-channel beamformer to create a beamformed signal.

[0084]

[0106] In some embodiments, one or more delayed signals may be summed by one or more summing amplifiers to form multiple microbeamformed signals.

[0107] In some embodiments, the method may further include, after (c), providing the plurality of microbeamformed signals to one or more converters. In some embodiments, the one or more converters may comprise analog-to-digital converters. In some embodiments, the one or more converters may be configured to provide digital representations of the microbeamformed signals.

[0085]

[0108] In some embodiments, the multi-channel beamformer can be configured to aggregate digital representations of the microbeamformed signals to provide a digital representation of the beamformed signal, hi some embodiments, the multi-channel beamformer can be configured to delay and combine multiple microbeamformed signals to create the beamformed signal.

[0086]

[0109] In some embodiments, the one or more time delay values ​​can be adjusted using a plurality of delay calculation circuits, in some embodiments, the plurality of delay circuits comprises analog delay circuits and / or digital delay circuits.

[0087]

[0110] In some embodiments, one or more signals for ultrasound imaging can be received from (i) an array of transducer elements, or (ii) one or more receiver circuits operably coupled to the array of transducer elements. In some embodiments, the array of transducer elements can comprise one or more PMUT elements and / or one or more CMUT elements. In some embodiments, the array of transducer elements can comprise a one-dimensional array, or a two-dimensional array, such as a two-dimensional array on a curved surface.

[0088]

[0111] In some embodiments, the focal point characterizing the microbeamformed signal may move along a line of sight at a speed that is about half the propagation speed of the ultrasound signal in the material being imaged, hi some embodiments, the line of sight may correspond to at least a portion of the imaging path or imaging region of interest.

[0089]

[0112] example

[0113] In one aspect, the present disclosure provides a microbeamforming ultrasound imaging system. The microbeamforming ultrasound imaging system may comprise an array of transducer elements coupled to inputs of a plurality of receive circuits. In some embodiments, the plurality of receive circuit outputs may be coupled to inputs of a plurality of delay circuits, each delay circuit characterized by a time delay value, each providing a delay signal as an output. Optionally, the time delay values ​​characterizing the microbeamforming delay circuits may be controlled such that a focal spot characterizing the microbeamformed signal moves along the line of sight at a propagation speed. In some embodiments, the plurality of delay signals may be connected to inputs of a plurality of summing amplifiers. In some embodiments, each summing amplifier may provide as an output a microbeamformed signal representing a combination of the delay signals. In some embodiments, a plurality of representations of the plurality of microbeamformed signals may be coupled to inputs of a multi-channel beamformer, which provides a beamformed signal as an output.

[0090]

[0114] In some embodiments, the transducer elements can be coupled to an array of receive circuits. The receive circuit outputs can be passed through an array of delay circuits characterized by time delay values. The delay circuit outputs can be combined to form a plurality of microbeamformed signals characterized by focal points determined by the time delay values. The microbeamformed signals can be coupled to a multi-channel beamformer so that they can be further delayed and combined to form a beamformed signal. The time delay values ​​can be controlled in real time to move the focal point along a desired line of sight after each ultrasound pulse is transmitted at the expected propagation speed of the received ultrasound echo.

[0091]

[0115] 1 illustrates an example of a microbeamforming ultrasound imaging system. The microbeamforming ultrasound imaging system may include an array of transducer elements 10 connected to a number of receive circuits 12. The multiple receive circuits 12 may receive one or more outputs 11 from the array of transducer elements 10. The one or more outputs 11 may correspond to one or more signals received by the array of transducer elements 10.

[0092]

[0116] In some embodiments, the receiver circuit output 13 may be connected to the input of a number of delay circuits 14, each characterized by a time delay value and each providing a delayed signal 15 at its output. The time delay values ​​characterizing the delay circuits 14 may be substantially controlled by a number of delay calculation circuits as shown in FIG.

[0093]

[0117] In some embodiments, the delayed signals 15 may be connected to the inputs of multiple summing amplifiers 16. The summing amplifiers may be configured to combine multiple groups of delayed signals to form multiple microbeamformed signals 18.

[0094]

[0118] In some embodiments, the microbeamformed signals 18 may be connected to inputs of multiple analog-to-digital converters (ADCs) 19, each ADC 19 providing at least one of multiple digital representations 20 of the microbeamformed signal 18. Optionally, the digital representations 20 of the microbeamformed signals may be coupled to inputs of a multi-channel beamforming circuit 21, which may delay and combine the digital representations 20 to provide a digital representation of the beamformed signal 22.

[0095]

[0119] As shown in FIG. 2, the time delay values ​​characterizing the microbeamforming delay circuit 14 can be controlled such that the focal points 39, 42 characterizing the microbeamformed signal 18 move substantially along the line of sight 43 at the propagation speed.

[0096]

[0120] In a preferred embodiment, the transducer elements 10, receive circuitry 12, delay circuitry 14, and delay computation circuitry may be physically arranged to have at least one common pitch in at least one dimension.

[0097]

[0121] 4 shows a preferred embodiment of a delay calculation circuit for controlling a time delay value characterizing an analog delay circuit. Optionally, the delay calculation circuit may use non-linear interpolation. Optionally, the delay calculation circuit may calculate an exponential decay term 73 by repeatedly multiplying a stored value of the exponential decay term 73 by a fractional value 72. Optionally, the delay calculation circuit may calculate a sum 78 of the exponential decay term 73 and a constant term 77. The sum 78 determines a time delay value (T DELAY ) can be controlled. In one non-limiting embodiment, the analog delay circuit 86 can comprise an analog sample and hold delay circuit of the type shown in FIG.

[0098]

[0122] In some embodiments, a counter 82 can provide a value 81 that can control the connection of capacitors 53 and 54 to output amplifier 57. Optionally, a summer 79 can provide a value 80 that can control the connection of capacitors 53 and 54 of the delay circuit shown in FIG. 3 to the delay circuit's input amplifier 50. Optionally, the delay circuit's output amplifier 57 can provide an output at time (t) that represents the value of the input to input amplifier 50 at a previous time (tT DELAY ). As described elsewhere herein, the time delay value (T DELAY ) can be controlled, adjusted, or otherwise modified by a delay calculation circuit.

[0099]

[0123] Ultrasound Imaging Systems - Types of Signals Used

[0124] In any of the embodiments described herein, the ultrasound imaging system may use various representations of the ultrasound signal, the input signal, the output signal, the delayed signal, the microbeamformed signal, and / or the fully beamformed signal.

[0100]

[0125] In some cases, the ultrasound imaging system may use analog signals represented by one or more of a voltage, current, impedance, pressure, or charge state. The analog signals may include, for example, single-ended signals (such as a single voltage or current) or differential signals (such as the difference between a pair of voltages or currents).

[0101]

[0126] In some cases, ultrasound imaging systems may use digital signals, which may be represented by multi-bit parallel binary signals or bit-serial binary signals.

[0102]

[0127] In some cases, the ultrasound imaging system may use one or more analog signals and / or one or more digital signals, and in some cases, the ultrasound imaging system may include one or more converters for converting between analog and digital signals or between digital and analog signals.

[0103]

[0128] Ultrasound Imager / Imaging Probe

[0129] The systems and methods described herein can be used with any type of imaging device, including optical and acoustic imaging devices. In some cases, the optical imaging device can include a camera, a CMOS sensor, a CCD sensor, or any other type of sensor configured for imaging based on optical signals. In some cases, the acoustic imaging device can include an ultrasound imaging device. In some non-limiting embodiments, the imaging device can be configured as a handheld ultrasound imaging probe.

[0104]

[0130] Ultrasound imaging (sonography) uses high frequency sound waves to see inside the body. Because ultrasound images are captured in real time, they can show the movement of internal organs as well as blood flow through blood vessels. Sound waves can also be used to create and display images of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs.

[0105]

[0131] To perform imaging, imaging devices transmit signals into the body and receive signals reflected from the body part being imaged. Types of imaging devices include transducers, which can also be called transceivers or imagers, and can be based on photoacoustic or ultrasonic effects. Such transducers can be used in imaging as well as other applications. For example, transducers can be used in medical imaging to observe the anatomical structures of tissues or other organs in the body. Transducers can also be used in industrial applications such as material testing, or in therapeutic applications such as localized tissue heating in HIFU-based procedures. Doppler measurement techniques are used when imaging a target and measuring the movement of the target, such as blood flow speed and direction. Doppler techniques are also applicable in industrial applications to measure flow rates, such as the flow of fluids or gases in a pipe. Doppler measurements can be made based on the difference in frequency between the transmitted and reflected waves due to relative motion between the source and the object. The frequency shift is proportional to the speed of movement between the transducer and the object. Ultrasound imaging utilizes this effect to determine the speed and direction of blood flow.

[0106]

[0132] In some embodiments, the transducer elements described herein (e.g., pMUT elements, cMUT elements, etc.) may be interchangeably referred to as transceiver elements. In some cases, the transducer elements described herein may comprise piezoelectric or piezo elements. In some embodiments, the transducer elements described herein may include one or more of a substrate, a membrane depending from the substrate, a bottom electrode disposed on the membrane, a piezoelectric layer disposed on the bottom electrode, and one or more top electrodes disposed on the piezoelectric layer.

[0107]

[0133] In ultrasound imaging, a transducer can be used to transmit an ultrasonic beam towards the target to be imaged. The reflected waveform is received by the transducer and converted into an electrical signal, and further signal processing produces an image. Arrays of micromechanical ultrasonic transducers (MUTs) can be used to measure the speed and direction of flow.

[0108]

[0134] The ultrasound device disclosed herein can be configured for B-mode imaging. B-mode imaging for anatomical structures is a two-dimensional ultrasound image display composed of dots representing ultrasound echoes. The brightness of each dot can be determined by the amplitude of the returned echo signal, which allows visualization and quantification of anatomical structures, as well as visualization of diagnostic and therapeutic procedures. Typically, B-mode images closely resemble the actual anatomical structures in a cutaway view in the same plane. In B-mode imaging, the transducer is first placed in a transmission mode and then in a reception mode to receive echoes from the target. The echoes are signal processed into an image of the anatomical structures. The transducer elements are programmable to be in either a transmission mode or a reception mode, but not simultaneously.

[0109]

[0135] The ultrasound device disclosed herein can be configured for color Doppler imaging. The use of color flow Doppler, color Doppler imaging, or simply color Doppler allows visualization of blood flow direction and velocity in arteries or veins within a user-defined area. Regions of interest are defined and the Doppler shift of the returning ultrasound is color-coded based on average velocity and direction. These images may overlap (be imaged simultaneously) with anatomical structure images in B-mode scanning to provide a more intuitive sense of flow relative to the anatomical structure being viewed. Doppler imaging can also be PW Doppler, where the extent and velocity of flow is determined, but the maximum flow rate depends on the pulse repetition frequency used, otherwise the image will alias and faster speeds will appear slower. Doppler shift can be measured from the collection of waves received to measure flow velocity using the PW mode of Doppler imaging. CW Doppler is a continuous imaging technique, where aliasing is avoided by continuously transmitting from one transducer element while receiving echoes from another transducer element. Programmable instruments can implement both pulsed and continuous techniques, as discussed below. PW and color Doppler can use a selected number of elements in the array. First, the elements are placed in a transmit mode, and after the echoes are returned, the elements are placed in a receive mode and the received signal is processed for Doppler signal imaging. For CW Doppler, at least two different elements are utilized, each element in a transmit mode while the other element is continuously in a receive mode.

[0110]

[0136] The ultrasound imaging device disclosed herein can be configured for two-dimensional (2D) imaging and / or three-dimensional (3D) imaging. In some embodiments, the ultrasound imaging device can utilize one or more arrays of MEMS (microelectromechanical system) ultrasound transducers, such as pMUTs (piezoelectric micromechanical ultrasound transducers) and / or cMUTs (capacitive micromechanical ultrasound transducers). The micromechanical ultrasound transducers (MUTs) can be arranged in a lateral array. In some cases, the MUTs can be arranged in a regular or symmetrical configuration. In other cases, the MUTs can be arranged in a staggered or asymmetrical configuration. In some cases, the transducer elements can be arranged in a rectangular lattice. In other cases, the elements can be arranged in, for example, a circular configuration, a rhombus (equilateral parallelogram), a hexagon, an annulus, or any lattice. These arrays can be located on curved surfaces as well as planar arrays.

[0111]

[0137] 5 illustrates an example system 511 that may be used for imaging (e.g., ultrasound imaging) of a target region 513. The system 511 may include an imaging device (e.g., any of the imaging devices shown or described herein). The imaging device may be configured to transmit and receive one or more signals 512. The one or more signals 512 may include signals transmitted to and / or reflected from the target region 513.

[0112]

[0138] 6 shows a block diagram of an imaging device 100 having a transmit channel 106 and a receive channel 108 controlled by a control circuit 109, and a computing device 110 configured to implement various imaging calculations. The imaging device 100 may optionally include a power source 111 for powering various components of the imaging device 100. In some cases, the computing device 110 and / or the power source 111 may be located external to the imaging device 100.

[0113]

[0139] In some embodiments, the imaging device 100 can be used to generate images of internal tissues, bones, blood flow, or organs of a human or animal body. In some cases, the imaging device 100 transmits signals into the body and receives signals reflected from the body part being imaged. Such an imaging device 100 can include, for example, a piezoelectric transducer 102, which may also be referred to herein as a transceiver or imager, and can be based on photoacoustic or ultrasonic action. The imaging device 100 can be used to image other objects as well. For example, the imaging device 100 can be used for medical imaging, fluid or gas flow measurement in pipes, lithotripsy, and localized tissue heating for therapeutic and high intensity focused ultrasound (HIFU) procedures.

[0114]

[0140] In addition to use with human patients, imaging device 100 can be used to image the internal organs of animals as well. Furthermore, in addition to imaging internal organs, imaging device 100 can also be used to determine the direction and velocity of blood flow in arteries and veins, as well as tissue stiffness, by Doppler mode imaging.

[0115]

[0141] Different types of imaging can be performed using imaging device 100. For example, imaging device 100 can be used to perform one-dimensional imaging, also known as A-scan, 2D imaging, also known as B-scan (B-mode), three-dimensional (3D) imaging, also known as C-scan, and Doppler imaging. Imaging device 100 can be switched to different imaging modes and can be electronically configured under program control.

[0116]

[0142] To facilitate imaging, the imaging device 100 includes an array of piezoelectric transducers 102, each of which includes an array of piezoelectric elements 104. The piezoelectric elements 104 may also include two of more subelements, each of which may be configurable with transmit and / or receive operations. The piezoelectric elements 104 may operate to 1) generate waves (e.g., sound waves or pressure waves) that can pass through the body or other mass, and 2) receive waves reflected from an object or other mass within the body to be imaged.

[0117]

[0143] In some examples, the imaging device 100 can be configured to simultaneously transmit and receive ultrasonic waveforms. For example, certain piezoelectric elements 104 can transmit pressure waves toward a target object being imaged, while other piezoelectric elements 104 receive pressure waves reflected from the target object and generate electrical charges in response to the received waves. These charges can be interpreted and / or processed to generate an image of the target object or a portion thereof.

[0118]

[0144] In some examples, each piezoelectric element 104 can emit or receive signals at a particular frequency, known as a center frequency, as well as at second and / or additional frequencies. Such multi-frequency piezoelectric elements 104 can be referred to as multi-mode piezoelectric elements 104 and can extend the bandwidth of the imaging device 100.

[0119]

[0145] The piezoelectric material forming the piezoelectric element 104 can contract and expand when different voltage values ​​are applied at a particular frequency. In response, when different values ​​of voltage are alternately applied, the piezoelectric element 104 can convert electrical energy (i.e., voltage) into mechanical motion resulting in acoustic energy, which is emitted as waves at a desired frequency. These waves are reflected from the target being imaged and received by the same piezoelectric element 104 and converted into electrical signals, which are then used to form an image of the target.

[0120]

[0146] To generate the pressure waves, the imaging device 100 may utilize multiple transmit channels 106 and multiple receive channels 108. The transmit channels 106 include multiple components that drive the transducer 102 (i.e., an array of piezoelectric elements 104) with voltage pulses at a responsive frequency, causing an ultrasonic waveform to be emitted from the piezoelectric elements 104 toward the object to be imaged. The ultrasonic waveform travels toward the object to be imaged, a portion of the waveform is reflected back to the transducer 102, and the receive channels 108 collect the reflected waveform and convert it to electrical energy that can be processed, for example, by a computing device 110 to create an image that can be displayed and interpreted by a human or a computer.

[0121]

[0147] In some examples, the number of transmit channels 106 and receive channels 108 in the imaging device 100 remains constant, but the number of piezoelectric elements 104 coupled to those channels can vary. This coupling can be controlled by control circuitry 109. In some examples, portions of the control circuitry 109 can be distributed among the transmit channels 106 and receive channels 108. For example, the piezoelectric elements 104 of the transducer 102 can be formed in a 2D array having N columns and M rows.

[0122]

[0148] In one example, the 2D array of piezoelectric elements 104 can have multiple columns and rows, for example, 128 columns and 32 rows. The imaging device 100 can have up to 128 transmit channels 106 and up to 128 receive channels 108. Each transmit channel 106 and receive channel 108 can be coupled to multiple or a single piezoelectric element or subelement 104. Depending on the imaging mode, each column of piezoelectric elements 104 can be coupled to a single transmit channel 106 and a single receive channel 108. The transmit channel 106 and receive channel 108 can receive a composite signal, which combines the signals received at each piezoelectric element 104 in the respective row or column. In another example (i.e., during different imaging modes), each individual piezoelectric element 104 can be coupled to its own transmit channel 106 and its own receive channel 108.

[0123]

[0149] 7 illustrates another exemplary embodiment of an ultrasound imaging system 700 disclosed herein. The imaging system 700 may include a handheld device 710 having a display unit 712 and a data recording unit, and is enabled for connection by a communication interface to a network 1200 and an external database 1220, such as an electronic health record. Such connection to an external data source may facilitate medical billing, data exchange, medical history, or other medical related information communication. The system 700 may include an ultrasound imager (also referred to herein as a "probe") 726 including an ultrasound imager assembly (interchangeably referred to herein as a "tile assembly") 708, where the ultrasound tile has one or more arrays of pMUTs 702 fabricated on a substrate. The array of pMUTs 702 may be configured to emit and receive ultrasound waveforms.

[0124]

[0150] The pMUT array 702 may be operatively coupled to (i) an application specific integrated circuit (ASIC) 1060 located in close proximity to the pMUT array 702, and / or (ii) a separate control unit 1100 located remotely from the pMUT array 702. The array may be coupled to an impedance reducing and / or impedance matching material 704, which may be located adjacent to the pMUT array. In some embodiments, the imager 726 includes a rechargeable power source 1270 and / or a connection interface 1280 to an external power source, e.g., a USB interface. In some embodiments, the imager 726 includes an input interface 1290 for an ECG signal to synchronize scanning to an ECG pulse. In some embodiments, the imager 726 has an inertial sensor 1300 to assist with user guidance.

[0125]

[0151] In some embodiments, many pMUT arrays can be batch manufactured at low cost. Furthermore, the integrated circuit can also be designed to have dimensions such that the connections required to communicate with the pMUTs are aligned with each other and can be connected to a matching integrated circuit located vertically below or proximal to the array, typically a distance of about 25 μm to 100 μm, for example. Larger arrays of pMUT elements can also be realized by using multiple pMUT arrays with multiple matching ASICs, assembling them adjacent to each other and covering them with an appropriate amount of impedance matching material. Alternatively, a single array can have a large number of pMUT elements arranged in a rectangular array or other shape, with the number of pMUT elements ranging from less than 1000 to 10,000. The pMUT array and multiple pMUT elements can be connected to a matching ASIC.

[0126]

[0152] Arrow 1140 indicates an ultrasound transmit beam from the imager assembly 708 targeted at the body part 1160 to image a target 1180. The transmit beam is reflected by the target being imaged and enters the imager assembly 708, as indicated by arrow 1140. In addition to the ASIC 1060, the imaging system 700 may include other electronic control, communication, and computation circuitry 1100. It will be appreciated that the ultrasound imager 708 may be a single freestanding unit or may include physically separate but electrically or wirelessly connected elements, such as the electronic control unit 1100.

[0127]

[0153] Optionally, the ASIC 1060 may comprise one or more low noise amplifiers (LNAs). The pMUT may be connected to the LNA via a switch in receive mode. The LNA converts the charge in the pMUT, generated by the reflected ultrasound beam exerting pressure on the pMUT, into a low-noise, amplified voltage signal. The signal-to-noise ratio of the received signal may be one of the main factors determining the quality of the reconstructed image. It is therefore desirable to reduce the inherent noise of the LNA itself. This noise reduction may be achieved by increasing the transconductance of the input stage of the LNA. This increase in transconductance may be achieved, for example, by using a higher current in the input stage. A higher current may increase power dissipation and heat. However, if a low-voltage pMUT is used in close proximity to the ASIC, the power saved by the low-voltage pMUT may be utilized to reduce the noise in the LNA for a given acceptable total temperature rise compared to a transducer operating at a higher voltage.

[0128]

[0154] In some alternative embodiments, the imager may include a transceiver array for transmitting and receiving pressure waves, and features or components for directing the propagation direction of the pressure waves and / or focusing the pressure waves. The imager may also include a control unit, such as an ASIC for controlling the transceiver array, coupled to the transducer array. The combination of the transceiver array and the ASIC connected to the transceiver array may constitute a tile. Additional components may include one or more field programmable gate arrays (FPGAs) for controlling the components of the imager, circuits such as an analog front end (AFE) for processing / conditioning the signals, and acoustic absorbing materials for absorbing waves generated by the transducer array and propagating toward the circuits. Additional components may optionally include a communication unit for communicating data with an external device via one or more ports, a memory for storing data, a battery for providing a more portable power source to the components of the imager, and / or a display for displaying a user interface and ultrasound derived images.

[0129]

[0155] In some cases, during operation of the imager, a user can contact the pMUT surface covered by the interface material with a body part area, and ultrasound is transmitted toward a target to be imaged at the body part area. The imager receives an ultrasound beam reflected from the imaging target and processes or transmits the reflected beam to an external processor for image processing and / or reconstruction, and then to a handheld device for displaying the image.

[0130]

[0156] For example, when using an imager to image a human or animal body part, the transmitted ultrasound waveform can be directed towards the target. Contact with the body can typically be achieved by applying a gel to the body and placing the imager in the gel, then holding the imager in close proximity to the body, allowing an excellent interface for the emitted ultrasound to enter the body and for the ultrasound waveform reflected from the target to re-enter the imager, where the reflected signal is used to create an image of the body part, and the results, including graphs, plots and statistics, are displayed on a screen and shown in various formats with or without an image of the body part.

[0131]

[0157] In some embodiments, the imager / probe may be configured such that certain parts are physically separate but connected via a cable or wireless communication connection. In one example, the pMUT assembly and ASIC as well as any control and communication related electronics may reside in a unit often referred to as the probe. The part of the device or probe that contacts the body part may comprise the pMUT assembly.

[0132]

[0158] Signal Processing Parameters

[0159] In some cases, a computing device (e.g., a processor or computer) can identify or determine optimal parameters for processing one or more ultrasound signals. The optimal parameters can include, for example, a time delay applied to one or more of the ultrasound signals.

[0133]

[0160] In some cases, these parameters can be automatically detected based on one or more images taken using the imaging device. For example, image analysis algorithms can be used to analyze images taken by the imaging device to determine optimal parameters. In other cases, these parameters can be automatically detected based on one or more sensor readings or measurements (e.g., from an accelerometer or motion sensor operably coupled to any of the imaging devices or scanning systems described herein). Alternatively, a user of the imaging device can manually input the desired parameters (e.g., time delay values).

[0134]

[0161] Scanning parameters

[0162] In some embodiments, scanning parameters that control the operation of the imaging systems and devices described herein may be adjusted based on the time delay value used. In some cases, the scanning parameters may be controlled or adjusted differently for different imaging operations, different users, and / or different imaging devices.

[0135]

[0163] In some embodiments, the scanning parameters can include, for example, a transmit pulse, a pulse width, a pulse power, a pulse repetition interval, a pulse sequence, a pulse timing, a pulse period, a transmit frequency, a pulse start time, a pulse end time, a pulse duration, or a pulse type (e.g., a unipolar pulse, a multi-state bipolar pulse), or any other characteristic associated with a pulse transmittable by an imaging device. The pulse can include an audio or ultrasound signal or wave. In some embodiments, the scanning conditions or parameters can include a pulse frequency, a pulse wavelength, a phase delay, or a phase difference between two or more pulses.

[0136]

[0164] In some embodiments, the scanning parameters can include a transmission focusing depth or a penetration depth. In some embodiments, the scanning parameters can include a number of beams, a type of beam (pulsed vs. continuous wave), a beam size, a beam shape (e.g., a beam origin, a beam directivity, a beam elevation / azimuth, or any other characteristic or feature of a beam that can be generated and transmitted by an imaging device). The beams can include sound or ultrasound signals or waves.

[0137]

[0165] In some embodiments, the scanning parameters can include a scanning mode. The scanning mode can include, for example, 2D imaging or 3D imaging. In some embodiments, the scanning parameters can include a scanning speed, a scanning direction, or a scanning pattern.

[0138]

[0166] In some embodiments, the scanning parameters can include an aperture (e.g., aperture size or aperture shape), hi some embodiments, the scanning parameters can include the type of filter used, transmission delay, gain, weighting or apodization of signals transmitted or received by individual transducer elements, decimation, line spacing, or number of collinear transmissions per unit time or unit area.

[0139]

[0167] Although the above description provides specific embodiments and examples, the subject matter extends beyond the specifically disclosed embodiments to other alternative embodiments and / or applications, as well as modifications and equivalents thereof. Thus, the scope of the claims appended hereto is not limited by the specific embodiments described. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable order and are not necessarily limited to any particular disclosed order. Although various operations may be described as multiple separate operations to aid in understanding a particular embodiment, the order of description should not be construed to imply that these operations are order-dependent. In addition, the structures, systems, and / or devices described herein may be implemented as integrated or separate components.

[0140]

[0168] For purposes of comparing various embodiments, certain aspects and advantages of those embodiments have been described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be implemented to achieve or optimize one advantage or group of advantages taught herein, but not necessarily achieve other aspects or advantages that may also be taught or suggested herein.

[0141]

[0169] In this specification, A and / or B include one or more of A or B, and combinations thereof such as A and B. In this specification, terms such as "first", "second", "third", etc. may be used to describe various elements, components, regions, and / or sections, but it is understood that these elements, components, regions, and / or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, or section from another element, component, region, or section. Thus, without departing from the teachings of the present disclosure, a first element, component, region, or section discussed below can also be referred to as a second element, component, region, or section.

[0142]

[0170] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. In this specification, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", or "includes" and / or "including", as used herein, specify the presence of the stated features, regions, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof.

[0143]

[0171] As used herein and in the claims, unless otherwise stated, the terms "about" and "approximately" or "substantially" refer to a variation of no more than ±0.1%, ±1%, ±2%, ±3%, ±4%, ±5%, ±6%, ±7%, ±8%, ±9%, ±10%, ±11%, ±12%, ±14%, ±15%, or ±20% of the numerical value, depending on the embodiment. As a non-limiting example, about 100 meters refers to a range of 95 meters to 105 meters (i.e., ±5% of 100 meters), 90 meters to 110 meters (i.e., ±10% of 100 meters), or 85 meters to 115 meters (i.e., ±15% of 100 meters), depending on the embodiment.

[0144]

[0172] Although preferred embodiments have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and substitutions will occur to those skilled in the art without departing from the scope of the present disclosure. In fact, it should be understood that various alternatives to the embodiments described herein can be used. Many different combinations of the embodiments described herein are possible, and such combinations are considered to be part of the present disclosure. In addition, all features discussed in connection with any one embodiment herein can be easily adapted for use with other embodiments herein. The following claims define the scope of the present disclosure, and it is intended to cover methods and structures within the scope of these claims and their equivalents.

Claims

1. an array of transducer elements; a plurality of receiver circuits configured to provide one or more output signals, the plurality of receiver circuits comprising at least one input coupled to at least one transducer element of the array of transducer elements; a plurality of delay circuits configured to output one or more delayed signals, the delay circuits having one or more inputs coupled to at least one of the plurality of receiving circuits, the plurality of delay circuits characterized by a plurality of time delay values; 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 representing a combination of delayed signals from the plurality of delay circuits; the plurality of time delay values ​​are controllable or adjustable such that one or more focal points characterizing the microbeamformed signal move along a line of sight; Ultrasound imaging system.

2. The ultrasound imaging system of claim 1 , wherein at least one of the plurality of receive circuits comprises a time gain compensation circuit.

3. The ultrasound imaging system of claim 1 , wherein at least one of the plurality of delay circuits comprises an analog sample and hold delay circuit.

4. 4. The ultrasound imaging system of claim 1, wherein at least one of the plurality of delay circuits constitutes an analog delay circuit, and the multi-channel beamformer constitutes an analog multi-channel beamformer.

5. 5. The ultrasound imaging system of claim 1, wherein at least one of the plurality of delay circuits constitutes an analog delay circuit, and the multi-channel beamformer constitutes a digital multi-channel beamformer.

6. 6. The ultrasound imaging system of claim 1, wherein at least one of the plurality of delay circuits constitutes a digital delay circuit, and the multi-channel beamformer constitutes a digital multi-channel beamformer.

7. The ultrasound imaging system of any one of claims 1 to 6, wherein the array of transducer elements forms a one-dimensional array.

8. The ultrasound imaging system of any one of claims 1 to 7, wherein the array of transducer elements forms a two-dimensional array.

9. The ultrasound imaging system of any one of claims 1 to 8, wherein the transducer elements constitute one or more PMUT elements.

10. The ultrasound imaging system of any one of claims 1 to 9, wherein the transducer elements comprise one or more CMUT elements.

11. 11. The ultrasound imaging system of claim 1, wherein the focal point characterizing the microbeamformed signal moves substantially along the line of sight at a speed that is approximately half the propagation speed of the ultrasound signal in the material being imaged.

12. The ultrasound imaging system of any one of claims 1 to 11, wherein the line of sight corresponds to at least a portion of an imaging path or an imaging region of interest.

13. an array of transducer elements; a plurality of receive circuits configured to provide one or more output signals, each of the plurality of receive circuits comprising at least one input coupled to at least one transducer element of the array of transducer elements; a plurality of delay circuits configured to output one or more delayed signals, the delay circuits having one or more inputs coupled to at least one receiver circuit of the plurality of receiver circuits; a plurality of delay calculation circuits configured to control or adjust one or more time delay values ​​characterizing said plurality of delay circuits; 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 representing a combination of delayed signals from the plurality of delay circuits; An ultrasound imaging system comprising:

14. 14. The ultrasound imaging system of claim 13, wherein the plurality of delay calculation circuits are configured to control or adjust the one or more time delay values ​​such that one or more focal points characterizing the microbeamformed signal move along a line of sight at a propagation velocity.

15. 15. The ultrasound imaging system of claim 13 or 14, wherein at least one delay calculation circuit of the plurality of delay calculation circuits is configured to calculate at least one time delay value by adding at least one constant term and at least one exponential decay term.

16. 16. The ultrasound imaging system of claim 13, wherein at least one delay calculation circuit of the plurality of delay calculation circuits is configured to calculate the one or more time delay values ​​using a linear interpolation algorithm.

17. 17. The ultrasound imaging system of claim 13, wherein at least one delay calculation circuit of the plurality of delay calculation circuits is configured to calculate the one or more time delay values ​​using a Coordinate Rotation Digital Computation (CORDIC) algorithm.

18. The ultrasound imaging system according to any one of claims 13 to 17, wherein at least one of the plurality of receiving circuits constitutes a time gain compensation circuit.

19. The ultrasound imaging system according to any one of claims 13 to 18, wherein at least one delay circuit of the plurality of delay circuits constitutes an analog sample and hold delay circuit.

20. 20. The ultrasound imaging system of claim 13, wherein at least one of the plurality of delay circuits constitutes an analog delay circuit, and the multi-channel beamformer constitutes an analog multi-channel beamformer.

21. 21. The ultrasound imaging system of claim 13, wherein at least one of the plurality of delay circuits constitutes an analog delay circuit, and the multi-channel beamformer constitutes a digital multi-channel beamformer.

22. 22. The ultrasound imaging system of claim 13, wherein at least one delay circuit among the plurality of delay circuits constitutes a digital delay circuit, and the multi-channel beamformer constitutes a digital multi-channel beamformer.

23. The ultrasound imaging system of any one of claims 13 to 22, wherein the array of transducer elements forms a one-dimensional array.

24. The ultrasound imaging system of any one of claims 13 to 23, wherein the array of transducer elements forms a two-dimensional array.

25. The ultrasound imaging system of any one of claims 13 to 24, wherein the array of transducer elements forms a two-dimensional array on a curved surface.

26. The ultrasound imaging system of any one of claims 13 to 25, wherein the transducer elements constitute one or more PMUT elements.

27. The ultrasound imaging system of any one of claims 13 to 26, wherein the transducer elements comprise one or more CMUT elements.

28. 28. The ultrasound imaging system of claim 13, wherein the transducer elements, the receiving circuitry, the delay circuitry, and the delay calculation circuitry are configured or physically arranged to have at least one common pitch in at least one dimension.

29. The ultrasound imaging system of any one of claims 13 to 28, further comprising one or more transducers.

30. 30. The ultrasound imaging system of claim 29, wherein the one or more converters comprise an analog-to-digital converter.

31. (a) receiving one or more signals for ultrasound imaging of a target area; (b) generating one or more delayed signals based on (i) the one or more signals for ultrasound imaging and (ii) one or more time delay values, the one or more time delay values ​​being adjustable to move one or more focal points characterizing the microbeamformed signals along a line of sight spanning at least a portion of the target region; (c) aggregating the one or more delayed signals to form a plurality of microbeamformed signals; (d) combining the plurality of microbeamformed signals using a multi-channel beamformer to produce a beamformed signal; The method includes:

32. 32. The method of claim 31 , in (c), summing the one or more delayed signals with one or more summing amplifiers to form the multiple microbeamformed signals.

33. 33. The method of claim 31 or 32, further comprising, after (c), providing the plurality of microbeamformed signals to one or more transducers.

34. 34. The method of claim 33, wherein the one or more converters comprise an analog-to-digital converter.

35. 35. The method of claim 33 or 34, wherein the one or more transducers are configured to provide a digital representation of the microbeamformed signal.

36. 36. The method of claim 35, wherein the multi-channel beamformer is configured to aggregate the digital representations of the microbeamformed signals to provide a digital representation of the beamformed signal.

37. A method according to any one of claims 31 to 36, wherein the multi-channel beamformer is configured to delay and combine the multiple microbeamformed signals to create the beamformed signal.

38. The method of any one of claims 31 to 37, wherein the one or more time delay values ​​are adjusted using a plurality of delay calculation circuits.

39. A method according to any one of claims 31 to 38, wherein the delayed signal is generated using one or more delay circuits.

40. 40. The method of claim 39, wherein the one or more delay circuits comprise analog delay circuits.

41. 40. The method of claim 39, wherein the one or more delay circuits comprise digital delay circuits.

42. 42. The method of any one of claims 31 to 41, wherein the one or more signals for ultrasound imaging are received from (i) an array of transducer elements, or (ii) one or more receive circuits operatively coupled to the array of transducer elements.

43. 43. The method of claim 42, wherein the array of transducer elements comprises one or more PMUT elements.

44. 43. The method of claim 42, wherein the array of transducer elements comprises one or more CMUT elements.

45. 43. The method of claim 42, wherein the array of transducer elements forms a one-dimensional array.

46. 43. The method of claim 42, wherein the array of transducer elements forms a two-dimensional array.

47. 47. A method according to any one of claims 31 to 46, wherein the focal point characterising the microbeamformed signal moves along the line of sight at a speed approximately half the propagation speed of the ultrasound signal in the material being imaged.

48. The method of any one of claims 31 to 47, wherein the line of sight corresponds to at least a portion of an imaging path or imaging region of interest.

Images