Patent Description:
Ultrasound imaging systems are widely used for medical imaging. An ultrasound imaging system typically includes a transducer probe separate from a main processing system. The transducer probe has an array of ultrasound transducer elements. The ultrasound transducer elements send acoustic waves through a patient's body and generate signals as the acoustic waves are reflected back by the tissues and/or organs within the patient's body. In traditional ultrasound applications, the timing and/or strength of the echo signals may correspond to the size, shape, and mass of the tissues, organs, or other features of the patient and images depicting the measured tissues, organs, or other features may be displayed to a user of the ultrasound system. Some ultrasound applications additionally employ continuous wave (CW) Doppler imaging methods to measure velocities within the patient's body, such as movement of liquid (e.g., blood flow). Typically, raw analog ultrasound echo signals corresponding to each transducer element are passed through a cable from the transducer probe to the main processing system for processing. For B-mode applications, the processing system processes the analog ultrasound signal by first digitizing them with analog to digital convertors and then further processing them using digital techniques and generates ultrasound images depicting tissues and/or organs within the patient. In CW Doppler applications, the processing system processes the analog ultrasound signal using analog mixers and filters to combine element data prior to digitization. Further processing of the digitized signal generates a graphical representation of velocities within the patient over time.

To transmit raw analog ultrasound echo signals from the probe to the main processing system, the connecting cable usually has many conductors, and in some instances, may require a conductor or set of conductors for each receiving ultrasound transducer element, making it thick, complex, cumbersome, and unwieldy. The size or diameter of the cable may also be large as the cable is required to carry received echo signals from each ultrasound transducer element to the main processing system. As a result, the cost of the cable can be the costliest component in an ultrasound imaging system. The cable may also have a high failure rate.

One approach to overcoming the limitations of analog processing is to include low-power analog-to-digital converters (ADCs) in the transducer probe, perform full or partial beamforming digitally at the transducer probe, and transfer the digital signals via a reduced number of conductors to the main processing system. This method, if used in traditional ultrasound imaging systems, may significantly reduce the cost, diameter, and overall maneuverability of the cable connecting the ultrasound imaging probe and the main processing system. However, due to the high dynamic range of CW Doppler ultrasound signals, such an approach is unsuitable for CW Doppler imaging. In particular, the low-power ADCs used to convert raw analog signals to digital signals within an ultrasound imaging probe do not have sufficient dynamic range to properly receive and convert analog signals associated with CW Doppler imaging. As a result, in ultrasound imaging systems with both a B-mode ultrasound imaging path and a CW Doppler path, ultrasound imaging signals for B-mode imaging may be converted to digital signals within the probe, but the signals for CW Doppler signals cannot be. Digital signals for B-mode imaging can be transmitted to the main processing system via a reduced number of conductors, but a separate set of conductors, including one or more conductors corresponding to each receiving transducer element, must be retained for carrying analog signals for CW Doppler imaging in the cable, resulting in the same undesired bulk and cost of transmitting analog signals.

<CIT> discloses an ultrasound diagnostic apparatus having a continuous wave (CW) Doppler mode. A line switching section is provided between an array transducer and a unit which has a CW transmission section and a CW reception section.

<CIT> discloses a Doppler apparatus and a method for acquiring Doppler mode data. The Doppler apparatus according to one embodiment acquires data at a pulse repetition frequency interval which can be set to a maximum.

<CIT> discloses systems and methods for detecting moving tissue of an object In one such method, a first and second ultrasound pulse are transmitted at a first sample volume of an object.

The present disclosure relates to systems, devices, and methods for continuous wave (CW) Doppler ultrasound imaging. An ultrasound system includes a host, a probe, and a connecting cable between the host and the probe. The ultrasound imaging probe includes an array of ultrasound transducers that transmit ultrasound signals toward an anatomy and receive waves reflected from the anatomy. The received ultrasound waves may be used for CW Doppler imaging of velocities within the patient's anatomy. An example of such a velocity is the velocity of blood flow, e.g., between chambers of the heart (e.g., between an atrium and a ventricle). Analog CW Doppler signals may be converted to digital signals within the ultrasound imaging probe. These digital CW Doppler signals may be combined within the probe before being transmitted to the ultrasound host via the connecting cable. Because digital data may be more easily combined, the number of conductors needed to transmit CW Doppler data may be significantly reduced by converting analog signals to digital signals within the probe. In turn, the cost of the cable may also be significantly decreased. The cable and probe may also become more easily managed and maneuvered by a sonographer. Accordingly, aspects of the present disclosure advantageously address shortcomings of existing ultrasound imaging systems.

The disclosure further relates to additional circuitry in the probe to convert analog CW Doppler signals to digital signals. Due to the limited dynamic range of analog-to-digital converters (ADCs), ADCs may be overdriven by the large dynamic range of analog CW Doppler signals. This results in poor data quality. Large signal slew rates result in large signal differences sample to sample. Subtle tissue and transducer positional motion can shift the sample in which the large signal transition occurs resulting in bright white spike artifacts in the Doppler display. Soft limiters and low pass filters may be positioned before ADCs in the signal processing path within the probe to reduce the dynamic range and slew rate of the analog CW Doppler signals. According to the invention, a switch engages unused ADCs associated with transmit transducers into parallel communication with ADCs associated with receive transducers. This parallel configuration doubles the ADCs used to convert analog CW Doppler signals and increases the combined dynamic range of the ADCs in the probe by at least <NUM> dB. This increase helps to prevent the ADCs from being overdriven and preserves good signal and data quality. Reducing the dynamic range of analog CW Doppler signals, increasing the dynamic range of the ADCs in the probe, and/or converting analog CW Doppler signals to digital at the probe advantageously eliminate the need of an analog signal path for CW Doppler imaging between the probe and the host in the ultrasound imaging system.

Specifically, the invention provides an ultrasound system according to claim <NUM>.

Preferred embodiments of the ultrasound system are specified in the dependent claims.

Further, the invention provides a method according to claim <NUM>.

<FIG> is a schematic diagram of an ultrasound imaging system <NUM>, according to aspects of the present disclosure. The system <NUM> is used for scanning a region, area, or volume of a patient's body. The system <NUM> includes an ultrasound imaging probe <NUM> in communication with a host <NUM> over a communication interface or link <NUM>. At a high level, the probe <NUM> emits ultrasound waves towards an anatomical object <NUM> (e.g., a patient's body) and receives ultrasound echoes that are reflected from the object <NUM>. The probe <NUM> transmits electrical signals representative of the received echoes over the link <NUM> to the host <NUM> for processing and image display. The probe <NUM> may be in any suitable form for imaging various body parts of a patient while positioned inside or outside of the patient's body. For example, the probe <NUM> may be in the form of a handheld ultrasound scanner or a patch-based ultrasound device. In some embodiments, the probe <NUM> can be an intra-body probe, such as a transesophageal echocardiography (TEE) probe, a catheter, or an endo-cavity probe. The probe <NUM> may include a transducer array <NUM>, various circuitry <NUM>, and a communication interface <NUM>.

The transducer array <NUM> emits ultrasound signals towards the object <NUM> and receives echo signals reflected from the object <NUM> back to the transducer array <NUM>. The transducer array <NUM> may include acoustic elements arranged in a one-dimensional (1D) array, <NUM>. X dimensional array, or a two-dimensional (2D) array. The acoustic elements may be referred to as transducer elements. Each transducer element can emit ultrasound waves towards the object <NUM> and can receive echoes as the ultrasound waves are reflected back from the object <NUM>. For example, the transducer array <NUM> can include M transducer elements producing M analog ultrasound echo signals <NUM>. In some embodiments, M can be about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or other suitable values both larger and smaller.

Circuitry <NUM> positioned within the probe <NUM> may be any of any suitable type and may serve several functions. For example, circuity <NUM> may include resistors, capacitors, transistors, inductors, relays, clocks, timers, or any other suitable electrical component that may be integrated in an integrated circuit. In addition, circuitry <NUM> may be configured to support analog signals and/or digital signals transmitted to or from the transducer array <NUM> and/or the probe <NUM>. In some embodiments, circuitry <NUM> may include analog frontends (AFEs), analog-to-digital converters (ADCs), multiplexers (MUXs), and encoders, among various other components. In some embodiments, the circuitry <NUM> can include hardware components, software components, and/or a combination of hardware components and software components.

The communication interface <NUM> is coupled to the circuitry <NUM> via L signal lines. In some embodiments, circuitry <NUM> may reduce the number of required lines from M signal lines to L signal lines. This may be accomplished by any suitable method using any suitable component. For example, MUXs, beamformers, or other components may be used to reduce the M signal lines from the transducer array <NUM> to L signal lines <NUM>. In the embodiment of <FIG>, L is less than M. The communication interface <NUM> may be configured to transmit the L signals <NUM> to the host <NUM> via the communication link <NUM>. The communication link <NUM> may include L data lanes for transferring the digital signals <NUM> to the host <NUM>, as described in greater detail herein. The communication interface <NUM> may include hardware components, software components, or a combination of hardware components and software components. The circuit <NUM> and/or the communication interface <NUM> are configured to generate signals <NUM>, carrying the information from the L signals <NUM>, for transmission over the communication link <NUM>. The signals <NUM> can be digital signals, analog signals, or a combination of digital signals and analog signals.

The host <NUM> may be any suitable computing and display device, such as a workstation, a personal computer (PC), a laptop, a tablet, a mobile phone, or a patient monitor. In some embodiments, the host <NUM> may be located on a moveable cart. At the host <NUM>, the communication interface <NUM> may receive the digital signals <NUM> from the communication link <NUM>. The communication interface <NUM> may include hardware components, software components, or a combination of hardware components and software components. The communication interface may be substantially similar to the communication interface <NUM> in the probe <NUM>.

Circuitry <NUM> positioned within the host <NUM> may be of any suitable type and may serve any suitable function. For example, circuity <NUM> may include resistors, capacitors, transistors, inductors, relays, clocks, timers, processing components, memory components, or any other suitable electrical component that may be integrated in an integrated circuit. In addition, circuitry <NUM> may be configured to support analog signals and/or digital signals transmitted to or from the probe <NUM>. Circuitry <NUM> may be configured to process signals <NUM> received from the probe <NUM>. For example, circuitry <NUM> may expand L signal lines received from the probe <NUM> to the original M signal lines corresponding to the specific transducer elements or groups/patches of transducer elements within the transducer array <NUM>. Circuitry <NUM> can be configured to generate image signals <NUM> for display to a user and/or perform image processing and image analysis for various diagnostic modalities or ultrasound types (B-mode, CW Doppler, etc.).

Circuit <NUM> and/or circuitry <NUM> may additionally include a central processing unit (CPU), a digital signal processor (DSP), a graphical processing unit (GPU), an application-specific integrated circuit (ASIC), a controller, a field-programmable gate array (FPGA), another hardware device, a firmware device, or any combination thereof. Circuit <NUM> and/or circuitry <NUM> may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a GPU and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The display unit <NUM> is coupled to circuitry <NUM>. The display unit <NUM> may include a monitor, a touch-screen, or any suitable display. The display unit <NUM> is configured to display images and/or diagnostic results processed by circuitry <NUM>. The host <NUM> may further include a keyboard, a mouse, a touchscreen or any suitable user-input components configured to receive user inputs for controlling the system <NUM>.

While <FIG> is described in the context of transmitting digital ultrasound echo signals from the probe <NUM> to the host <NUM> for display, the host <NUM> can generate signals for transmitting to the probe <NUM>. For example, power signals, signals for controlling the probe <NUM> (e.g.exciting the transducer elements at the transducer array <NUM> to emit energy) can be transmitted by the host <NUM> to the probe <NUM> over the communication link <NUM>.

<FIG> is a schematic diagram illustrating example circuitry of an ultrasound imaging system, according to aspects of the present disclosure. <FIG> provides a more detailed view of the system <NUM> including transmission paths from the probe <NUM> to the host <NUM> and from the host <NUM> to the probe <NUM>.

As shown in <FIG>, the probe <NUM> further includes an optional analog beamformer <NUM> and L transmit receive switches (T/R switches) <NUM>, preamplifiers <NUM>, analog-to-digital converters (ADCs) <NUM>, and transmit pulsers <NUM>. The probe <NUM> also includes a clock <NUM> and combiner <NUM>. <FIG> also illustrates the host <NUM>. The host <NUM> may include an integrated circuit <NUM>. The integrated circuit <NUM> may include in-phase/quadrature mixers <NUM>, <NUM>, and low pass filters (LPFs) <NUM>. The host <NUM> may additionally include a controller <NUM>, a power supply <NUM>, a plurality of wall filters <NUM> (with LPFs <NUM> and operational amplifiers (op-amps) <NUM>), and windowing functions <NUM>. The host <NUM> may also include, among other components configured to perform various functions, or operations, a component configured to perform a fast Fourier transform (FFT) <NUM>, a component to perform various conditioning functions <NUM>, and a display <NUM>. The host <NUM> may additionally include hardware components, software components, or a combination of hardware components and software components. As shown in <FIG>, the probe <NUM> and the host <NUM> may be connected with multiple conductors of a connecting cable <NUM> establishing signal communication. These conductors may include multiple signal lines including conductors, twisted pairs, and/or any other suitable means of transferring data. For example, the connecting cable <NUM> can include a power conductor <NUM> for transmitting power from the host <NUM> to the probe <NUM>. The cable <NUM> also includes a control signal line <NUM> for transmitting control and clock signals from the host <NUM> to the probe. The cable <NUM> can also include K signal lines <NUM> for transmitting signals from the probe <NUM> to the host <NUM>.

The signal path from the probe <NUM> to the host <NUM> may begin at the transducer array <NUM> shown in <FIG>. The transducer array <NUM> may include M transducer elements. As previously stated, in some embodiments, M can be any suitable number and the transducer elements may be of any suitable type and in any suitable arrangement. The transducer array <NUM> generates analog electrical signals representative of ultrasound echoes received at one or more transducer elements for any suitable imaging type (e.g., B-mode imaging, CW Doppler imaging, etc.). For CW Doppler imaging, one or more elements of the transducer array <NUM> are continuously emitting ultrasound energy simultaneously as one or more other elements of the transducer array <NUM> are continuously receiving ultrasound echoes (based on the emitted ultrasound energy). For example, half of the acoustic elements in the transducer array <NUM> can be transmitting while half of the acoustic elements in the transducer array <NUM> can be receiving. The transducer array <NUM> generates analog electrical CW Doppler data based on the ultrasound echoes received by the transducer elements in receive mode. In some embodiments, equal portions of the transducer array <NUM> operate in transmit mode and in receive mode for CW Doppler imaging.

The transducer array <NUM> may be in communication with an analog beamformer <NUM> via M signal lines. In some embodiments, the transducer array <NUM> may include many transducer elements. An analog beamformer <NUM> may be used to reduce the quantity of signal lines from the transducer array <NUM>. For example, in some embodiments, the analog beamformer <NUM> may delay and sum the signals received from the transducer array <NUM> to create a smaller subset. The analog beamformer <NUM> may be a receive beamformer and/or a transmit beamformer. In embodiments in which the analog beamformer is a transmit beamformer, the analog beamformer <NUM> may include or be in communication with high voltage pulse generation circuitry. In other embodiments, for example, in embodiments where the transducer array <NUM> is a one-dimensional array of transducer elements or the number of transducer elements is otherwise reduced, the analog beamformer <NUM> may not be necessary or included within the probe <NUM>. In some embodiments where the transducer array <NUM> is a one-dimensional array or the number of transducer elements is otherwise reduced, the analog beamformer <NUM> may still be included within the probe <NUM>.

The analog beamformer <NUM> may be in communication with multiple T/R switches <NUM> via a reduced number of signal lines (e.g. L signal lines). The probe <NUM> can include one T/R switch <NUM> for every transducer element of the array <NUM> or for every group/patch of transducer elements. T/R switches <NUM> may be configured to switch positions between different transmit and receive signal paths. For example, in a position for the transmit path, a T/R switch <NUM> may transmit a high voltage activation signal from the pulser <NUM> to one or more elements of the transducer array <NUM> to activate one or more transducer elements <NUM> to emit ultrasound energy. In receive mode, a T/R switch <NUM> may transmit receive signals corresponding to reflected waves received by the one or more transducer elements of the transducer array <NUM> to the preamplifier <NUM>. The T/R switches <NUM> may be in communication with the host <NUM> via the data line <NUM> and may receive instructions regarding switching between the transmit and receive signal paths through the data line <NUM>. The T/R switches <NUM> may also be in communication with the host <NUM> through any other suitable conductor or method.

The probe <NUM> may additionally include transmit pulsers <NUM>. The transmit pulsers <NUM> may receive a command signal generated by the host <NUM>. In response to the command signal, the transmit pulsers <NUM> generate electrical excitation pulses timed to cause the transducer array <NUM> to produce an acoustic transmit wave-front with any desired or specified focal characteristics.

The probe <NUM> may include L preamplifiers <NUM>. The preamplifiers <NUM> may amplify signals from the transducer array <NUM> received via the T/R switches <NUM> to improve the quality of received signals by, for example, reducing a noise floor. In some embodiments, the number of transmit pulsers <NUM> may be equal to the number of preamplifiers <NUM> and the number of T/R switches <NUM>. For example, each T/R switch <NUM> may be configured to receive data from one pulser <NUM> and transmit data from the transducer array <NUM> to one preamplifier <NUM>.

The receive signal path can be the same for CW Doppler imaging data and other imaging data (e.g., B-mode imaging data) from the transducer array to the preamplifiers <NUM>. At the preamplifiers <NUM>, the receive signal path diverges within the probe <NUM> to include different, parallel paths for CW Doppler imaging data and other imaging data. In the signal path for other imaging data, such as B-mode imaging data, each preamplifier <NUM> may be in communication with an ADC <NUM>. The ADCs <NUM> may be configured to convert analog ultrasound echo signals into digital ultrasound echo signals. For example, the ADCs <NUM> may receive analog ultrasound echo signals generated by the transducer array <NUM>, transmitted to the preamplifiers <NUM> via T/R switches <NUM>, and amplified by the preamplifiers <NUM> and convert them into digital ultrasound echo signals. Digital ultrasound echo signals may include digital samples representing the waveforms of corresponding analog ultrasound echo signals. The ADCs <NUM> may employ a successive approximation ADC architecture to provide high-performance and lower-power consumption, and thus may keep total power dissipation of the probe <NUM> to be within a thermal budget of the probe <NUM>. However, any suitable ADC architecture may be used for the ADCs <NUM>.

The clock <NUM> may function as a master clock in the probe <NUM>. The clock <NUM> may provide a clock signal to the ADCs <NUM> as well as other components within the probe <NUM>.

Each ADC <NUM> may be in communication with the combiner <NUM>. The combiner <NUM> is representative of circuitry that can reduce the total signal lines received from the ADCs <NUM> and reduce the number of required signal lines for transmitting data to the host <NUM>. The combiner <NUM> may reduce the number of signal lines by any suitable method. In some embodiments, the combiner <NUM> may include a summing node. The combiner <NUM>, as well as any other suitable component or circuitry within the system <NUM> may include features similar to those described in <CIT>, published as <CIT> and/or <CIT>, and corresponding to <CIT>. In some embodiments, the combiner <NUM> may multiplex data received from the ADCs <NUM> into high-speed serial links and then send the data to the host <NUM> to be processed. In some embodiments, the combiner <NUM> may be a digital beamformer that performs a second stage of beamforming (delaying and summing of signals) after the first stage of beamforming is completed by the analog beamformer <NUM>.

<FIG> additionally depicts the connecting cable <NUM> positioned between the probe <NUM> and the host <NUM>. The cable <NUM> may include multiple signal lines including conductors, twisted pairs, or any other suitable means of transferring data. For example, the cable <NUM> may include the data line <NUM>, power line <NUM>, and K signal lines <NUM>. The data line <NUM> may be in communication with a controller <NUM> within the host <NUM>. The controller <NUM> transmits control signals via the data line <NUM> for controlling the clock <NUM>, the ADCs <NUM>, the T/R switches <NUM>, the pulsers <NUM>, the analog beamformer <NUM>, the transducer array <NUM>, the combiner <NUM> or any other component within the probe <NUM>. In some embodiments, the data line <NUM> may be a twisted pair of conductors. In other embodiments, the data line <NUM> may be a single conductor or any other suitable signal communication conduit. In various embodiments, the command signals transmitted via the data line <NUM> may be analog or digital signals. When digital command signals are transmitted, the data may be transmitted via the data line <NUM> at any suitable bit rate, such as between <NUM> Mbit/s and 8Gbit/s, including values such as <NUM>. 4Gbit/s and/or other suitable values both larger and smaller.

The power line <NUM> may be in communication with a power supply <NUM> within the host <NUM> or at any other suitable location. The power line <NUM> may provide electrical power to various components within the probe <NUM>. In some embodiments, the power supply <NUM> can provide direct current (DC) power to the probe <NUM> via the power line <NUM>. In some embodiments, the power supply <NUM> may additionally provide power to components within the host <NUM>.

K signal lines <NUM> may correspond to a reduced number of signal lines output from the combiner <NUM>. The signal lines <NUM> carry digital ultrasound data for CW Doppler and B-mode imaging. In some embodiments, the signal lines <NUM> may include only a single signal line. In other embodiments, the signal lines <NUM> may include two or more signal lines. The cable <NUM>, and any corresponding conductors enclosed within the cable <NUM> for the data line <NUM>, the signal lines <NUM>, and/or the power line <NUM>, may be of any suitable length. For example, the cable <NUM> and all associated conductors may be <NUM> meter, <NUM> meters, <NUM> meters in length or more or any suitable length therebetween. The cable <NUM> can be referred to as a flexible elongate member. In some embodiments, the cable can be replaced with an optical or a wireless interface.

The host <NUM> may include an integrated circuit <NUM>. The integrated circuit <NUM> may comprise any suitable circuitry. In some embodiments, the integrated circuit <NUM> may be implemented in the form of an FPGA, application specific integrated circuit (ASIC), or any other suitable type of circuit. In other embodiments, the integrated circuit <NUM> may be a configurable processor, NPU, accelerator card, SoC, or any other component. The integrated circuit <NUM> may comprise in-phase/quadrature (I/Q) mixers <NUM>, <NUM> and low pass filters (LPFs) <NUM>. The I/Q mixers <NUM>, <NUM> and LPFs <NUM> may be digital components in that they are implemented as part of the integrated circuit <NUM> and operate on digital signals.

The signal lines <NUM> may transmit digital signal data from the combiner <NUM> to the integrated circuit <NUM>. At the integrated circuit <NUM>, signals may be transmitted to two paths corresponding to the I component of the signal associated with mixer <NUM> and the Q component of the signal associated with mixer <NUM>. The I mixer <NUM> and the Q mixer <NUM> may create two signals with a phase offset. For example, the I mixer <NUM> may define a sequence corresponding to a digital square wave (e.g., a sequence of +<NUM> and -<NUM>, or +<NUM> and <NUM>) and multiply the sequence with received signals. The Q mixer <NUM> may define a similar sequence but delayed with respect to the I sequence by one quarter period (<NUM> degrees) and multiply the sequence with received signals. The I and Q mixers <NUM> and <NUM> may multiply respective sequences in such a way to create a phase offset between the two signal paths. For example, in some embodiments, the phase offset may be <NUM>. The digital square wave sequences may be a square wave of any suitable frequency. For example, in the range of, but not limited to <NUM> to <NUM> The frequency of the generated digital square wave may correspond to the sample rate of the signals received by the I and Q mixers <NUM> and <NUM>. The signals transmitted from the probe <NUM> to the host <NUM> via K signal lines <NUM> may be of any suitable sample rate. For example, in some embodiments, the signals transmitted and mixed via the I mixer <NUM> and the Q mixer <NUM> may be in the range of, but not limited to <NUM> to <NUM>. In some embodiments, the sample rate is at least four times the Doppler frequency. The sample rate of sequences generated by the I mixer <NUM> and Q mixer <NUM> may consequently be some frequency less than the sample rate of the received signals.

After a signal is received at the host <NUM> and mixed by the I and Q mixers <NUM> and <NUM>, the signals may then be filtered via the LPFs <NUM>. The LPFs <NUM> may filter any high frequency content in the received signal such that the signal corresponds primarily to audio range content. In some embodiments, the LPFs <NUM> may be boxcar filters. For example, the LPFs <NUM> may sum or average a set number of samples within the received signal into sets. The LPFs <NUM> may group and sum sets of <NUM> samples. In other embodiments, LPFs <NUM> may sum sets in the range of but not limited to <NUM> to <NUM>. In embodiments in which the LPFs <NUM> include boxcar filters, the resulting sample rate may be reduced by the number of samples included in a particular set. In some embodiments, therefore, the sample rate of data signals after passing through the LPFs <NUM> may correspond to audio frequency ranges and can be processed using standard processing components. In other embodiments, the LPFs <NUM> may be any suitable low pass filter, such as FIR or IR digital filters, or any other suitable low pass filter.

The host <NUM> may additionally include one or more wall filters <NUM>. The wall filters <NUM> may be digital filters, operating on digital signal data. For example, the wall filters <NUM> may be circuitry within the host <NUM>. The wall filters <NUM> may further include LPFs <NUM>. The wall filters <NUM> may be configured to filter out low or high frequency Doppler signals corresponding to arterial walls or any other static tissue within a patient. The wall filter <NUM> may additionally filter high amplitude low frequency content from movement within a patient from, for example, heart beats, general patient or probe movement, or other sources. In some embodiments, the wall filter <NUM> may be an aggressive filter. In some embodiments, the wall filter <NUM> may be a <NUM>-point, <NUM> term Blackman-Harris filter or any other suitable filter. The wall filters <NUM> may also comprise high pass filters.

After signals are processed through the wall filters <NUM>, a windowing function <NUM> may be applied. The windowing function <NUM> may be applied by a digital multiplier or any other suitable electronic component. The windowing function <NUM> may apply various weights to the signal prior to additional processing. A fast Fourier transform (FFT) <NUM> may be applied to the signal data to create a Doppler spectrum associated with velocity of movement (e.g., blood flow) within a patient. Following the FFT <NUM>, the data may be conditioned at conditioning <NUM>. A graphical representation of the CW Doppler data may then output for display to a user via the display <NUM>. It is fully contemplated that any suitable form of data processing may be applied to the signal data at this or any stage in the circuitry of the present invention. For example, the host <NUM> may apply additional data processing techniques to enhance the quality of the signal data, identify or emphasize various characteristics or aspects of the signal data, etc. One or more of the signal processing components within the host <NUM> and/or probe <NUM> may be implemented as hardware, software, or a combination of hardware and software.

The signal pathway in <FIG> within the probe <NUM> may be shared for B-mode data and CW Doppler data. <FIG> illustrates the CW Doppler signal pathway within the host <NUM>. Some components of the CW Doppler signal pathway may be shared with the B-mode signal pathway (e.g., conditioning <NUM>, display <NUM>), whereas other components may be dedicated for CW Doppler processing (e.g., integrated circuit <NUM>, wall filters <NUM>, FFT <NUM>). The host <NUM> can include signal processing circuitry for generating and displaying B-mode images based on the ultrasound data obtained by the probe <NUM>.

<FIG> is a schematic diagram illustrating example circuitry of an ultrasound imaging system, according to aspects of the present disclosure. <FIG> specifically illustrates an embodiment in which the combiner <NUM> is positioned within the host <NUM> (instead of the probe <NUM>). In some embodiments, a serializer block <NUM> may be included within the probe <NUM> to stream the ADC data over high speed serial links to the host <NUM>. In such an embodiment, the combiner <NUM> may be a digital beamformer, which performs a second stage of beamforming after the first stage of beamforming is completed by the analog beamformer <NUM>. This embodiment may be advantageously implemented in order to simplify the signal processing circuitry within the probe <NUM>. In this manner, the probe <NUM> may be better able to satisfy weight and/or thermal constraints (e.g., maximum weight and/or temperature for the probe <NUM>), as well as to increase efficiency and reduce costs associated with manufacturing the probe <NUM>. The serializer block <NUM> may additionally include a current mode logic (CML) block. The serializer block <NUM> may convert signals received from the ADCs <NUM> or any other component within the probe <NUM> into a bit stream for transmission to the host <NUM>. It is also noted that the system <NUM> as shown in <FIG> and/or the probe <NUM> shown in <FIG> may additionally include a serializer block substantially similar to the serializer block <NUM> shown in <FIG>.

The serializer/CML <NUM> may rearrange lines in communication with the combiner <NUM> and/or the ADC's <NUM> into a high rate serial data stream. In some embodiments, the serializer/CML <NUM> may run at a higher data rate than other circuitry within the probe <NUM>. For example, the serial data stream may run at <NUM> whereas other circuitry within the ultrasound signal path may run at <NUM>. The serializer/CML <NUM> may operate in a similar manner to the serializer disclosed in PCT Patent Application <CIT>, titled "ULTRASOUND PROBE WITH MULTILINE DIGITAL MICROBEAMFORMER," and published as <CIT>. Accordingly, in one of the signals paths of the probe <NUM>, digital ultrasound data (e.g., B-mode data) can be transmitted from the probe <NUM> to the host <NUM> via the conductors <NUM>. The conductors <NUM> may be a twisted pairs of conductors. It is understood that embodiments of the probe can include the combiner <NUM>, the serializer <NUM>, and/or both the combiner <NUM> and the serializer <NUM>.

<FIG> is a graphical representation of a Doppler spectrum measured with an ultrasound imaging system, according to aspects of the present disclosure. The display <NUM> (<FIG>) may display to a user a Doppler spectrum similar to the Doppler spectrum <NUM>. The Doppler spectrum <NUM> may depict velocities of fluids and/or other objects within a patient. An axis in the direction <NUM> along the Doppler spectrum <NUM> may indicate a time dimension. The time dimension as illustrated in <FIG> by the direction <NUM> may be of any suitable unit. For example, the direction <NUM> may be measured in seconds, milliseconds, or any other suitable unit. A direction <NUM> along the Doppler spectrum <NUM> may indicate a velocity. In some embodiments, this velocity may correspond to the velocity of blood within the heart or a blood vessel of a patient. In some embodiments, the Doppler spectrum velocity may correspond to blood flow through a mitral valve within a heart. Velocity as shown along direction <NUM> may be measured in m/s, cm/s, mm/s, or any other suitable unit. The values <NUM> depicted in the Doppler spectrum <NUM> may indicate the velocity of a fluid at a determined location within a patient at a given time. For example, the values <NUM> may correspond to the velocity of blood in or around a mitral valve within a heart as it beats. Peaks <NUM> may correspond to moments of high velocity of blood flow. The doppler spectrum <NUM> may additionally depict one or more sampling errors <NUM>. Sampling errors <NUM> may be caused by full scale signal transitions seen at the output of the preamplifier <NUM> resulting from movement by or within a patient or from thermal noise. Sampling errors <NUM> may be caused by large slew rate acoustic signals associated with transmit energy coupling into the receive aperture overdriving the preamplifiers <NUM>. Such movement causing full scale signal transitions may include a heartbeat, general patient movement, probe movement, or any other sudden movements during a patient's ultrasound examination. These movements may cause a sudden change in outputs from the I mixer <NUM> and/or the Q mixer <NUM> (<FIG>) resulting in a shift between samples and a large change in output signal. The sampling errors <NUM> may result from jitter on the timing of the edges of the square wave at the I and Q mixers <NUM> and <NUM>. For example, sampling in the ADCs <NUM> will capture the signal level before the edge or after the edge depending on the instantaneous jitter. This uncertainty results in full scale sampling errors <NUM> which, after downstream processing, results in artefacts, or large white spikes, in the Doppler spectrum <NUM>. As described below, aspects of the present disclosure are directed to minimizing and/or eliminating sampling errors <NUM> within the Doppler spectrum <NUM>.

The Doppler spectrum <NUM> may be presented or depicted to a user in any suitable format. For example, the display <NUM> may additionally display to a user multiple metrics associated with the patient's anatomy. In some embodiments, the display <NUM> may include scales along any suitable direction of the Doppler spectrum <NUM>. The display <NUM> may further include calculated metrics such as averages, trends, predictions, or any other suitable metric. In some embodiments, the Doppler spectrum <NUM> may also be referred to as a trace or spectrum trace.

<FIG> is a schematic diagram illustrating example circuitry of an ultrasound imaging probe, according to aspects of the present disclosure. The probe <NUM> illustrated in <FIG> may be substantially similar to the probe <NUM>. The transducer array <NUM> may also include two sets of transducer/acoustic elements, a set of receiving transducers 112a and a set of transmitting transducers 112b. In some embodiments, the transducer elements may be referred to as acoustic elements. The probe <NUM> may include two circuitry blocks or signal paths, circuitry 520a in communication with the receiving transducer set 112a and circuitry 520b in communication with the transmitting transducer set 112b. The circuitry 520a may include a limiter <NUM>, a low pass filter <NUM>, and an ADC 220a. The circuitry 520b may include an ADC 220b. The circuitry 520a may be in communication with the circuitry 520b via a connecting conductor 522and switches <NUM>. An ultrasound imaging system <NUM> capable of performing CW Doppler imaging may include multiple transducer elements within the transducer array <NUM> and may include multiple circuitry blocks 520a and 520b. In some embodiments, each ADC 220a and 220b may correspond to one circuitry block 520a and 520b respectively.

In CW Doppler mode, the set 112b of transducer elements (e.g., half of the transducer elements) may be used to transmit acoustic waves, illustrated by an arrow <NUM> in <FIG>the set 112a may be used to receive reflected waves, illustrated by an arrow <NUM>.

In some embodiments, the ultrasound imaging system <NUM> may be capable of performing various ultrasound imaging functions in addition to CW Doppler imaging. For example, the ultrasound imaging system <NUM> may perform B-mode, C-mode, M-mode, power Doppler, color Doppler, shear wave, pulse inversion, and/or other imaging types. When performing other ultrasound imaging functions other than CW Doppler, the host can control one or more of the transducer elements within the transducer array <NUM> to selectively transmit acoustic waves illustrated by the arrow <NUM> and receive reflection waves illustrated by the arrow <NUM>.

Each transducer element may be in communication with an ADC. For example, each transducer element of the receiving set 112a may be in communication with an ADC 220a. In some embodiments, multiple transducer elements may be in communication with a single ADC 220a (e.g., when an analog beamformer is provided in the probe <NUM> between the ADCs <NUM> and the transducer array <NUM>). In such embodiments, any suitable number of transducer elements may be in communication with one ADC 220a. For example, <NUM>, <NUM>, <NUM>, <NUM>, or more transducer elements or any suitable values both larger and smaller may be in communication with an ADC 220a. Similarly, each transducer element within the transmitting set 112b may also be in communication with an ADC 220b or multiple transducer elements, including any number previously mentioned, may be in communication with a single ADC 220b. ADCs 220a may be substantially similar to ADCs 220b and both ADCs 220a and 220b may be substantially similar to ADCs <NUM> described herein.

The circuitry 520a may include the limiter <NUM>. The limiter <NUM> may be a filter configured to limit the dynamic range of signals received by transducer elements within the receiving set 112a while maintaining good signal behavior. In some embodiments, the limiter <NUM> may allow signals below a specified input power or level to pass unaffected while attenuating peaks of stronger signals that exceed the threshold. In some embodiments, the limiter <NUM> may be a clipper, a soft clipper, a hard limiter, or any other type of suitable limiter. The limiter <NUM> may include analog limiter circuitry. In some embodiments, the analog limiter circuitry of the limiter <NUM> may include soft limiter circuitry.

The circuitry 520a may additionally include a low pass filter <NUM> positioned in communication with the limiter <NUM>. The low pass filter <NUM> may allow signals of a frequency lower than a selected cutoff frequency and attenuate signals with frequencies higher than the cutoff frequency. The low pass filter <NUM> may additionally be referred to as high-cut filters in some applications. The low pass filters <NUM> may be of any suitable type. For example, the low pass filters <NUM> may be Butterworth filters, Chebyshev filters, Elliptic filters, Bessel filters, Gaussian filters, RC filters, RL filters, RLC filters, or higher order passive filters. In addition, the low pass filters <NUM> may include any suitable active filters and may be integrated within an integrated circuit. In some embodiments, one limiter <NUM> may be in communication with one low pass filter <NUM> as shown in <FIG>. In other embodiments, any suitable number of limiters <NUM> may be in communication with one low pass filter <NUM> or vice versa. The combination of the limiter <NUM> and the low pass filter <NUM> may provide the ADCs <NUM> with slow edges that result in smaller errors in the presence of jitter or motion, as previously described.

Both the limiters <NUM> and the low pass filters <NUM> together and/or separately may serve to reduce the dynamic range of signals received by transducer elements within the receiving set of transducer elements 112a. The limiters <NUM> and the low pass filters <NUM> may also serve to reduce effects of any full scale signal transitions similar to the sampling errors <NUM> (<FIG>) resulting from movement within a patient. This advantageously results in a more accurate and legible Doppler spectrum. In some embodiments, the parameters and/or specifications of the limiters <NUM> and/or the low pass filters <NUM> may reduce power consumption and thermal dissipation within the probe <NUM>. In addition, the parameters and/or specifications of the limiters <NUM> and/or the low pass filters <NUM> may be selected and/or arranged to preserve the overall signal integrity of the signal received from transducer elements within the receiving set 112a of transducer elements while adequately reducing the dynamic range of the signal so as not to overdrive the ADCs 220a.

In some embodiments, the limiters <NUM> and/or the low pass filters <NUM> may be replaced with any suitable non-linear circuit. For example, non-linear circuits with a compression type transfer function may be used without or in combination with either the limiters <NUM> or the low pass filters <NUM>. In addition, the circuitry may include analog gain compression circuitry. In some embodiments, this circuitry may be implemented via hardware. In other embodiments, this circuitry may be a software implementation.

To increase overall dynamic range of the analog to digital conversion process within the probe <NUM>, the probe <NUM> may additionally include conductors <NUM> and switches <NUM>. The conductors <NUM> may be any suitable material, shape, or size. The conductors <NUM> may extend from the signal path <NUM> of circuitry 520a to a switch <NUM> in communication with a signal path <NUM> of circuitry 520b. In some embodiments, each signal path <NUM> and/or circuitry 520a may correspond to one receiving transducer element and each signal path <NUM> and/or circuitry 520b may correspond to one transmitting transducer element. In such embodiments, the number of signal paths <NUM> may equal the number of signal paths <NUM> such that a single conductor <NUM> may be in communication with one signal path <NUM> and one signal path <NUM>. The conductor <NUM> may be positioned within the probe <NUM> such that one end of the conductor <NUM> is placed in communication with the signal path <NUM> between an ADC 220a and a low pass filter <NUM>. In addition, the positions of the limiter <NUM> and/or the low pass filter <NUM> need not be in the order shown in <FIG> but may be in any suitable order. The other end of the conductor <NUM> may be in communication with the signal path <NUM> and may be positioned at any suitable location along signal path <NUM>. In other embodiments, the signal path <NUM> may additionally include limiters <NUM> and/or low pass filters <NUM> similar to signal path <NUM>. Although only one signal path <NUM> and one signal path <NUM> are shown depicted in <FIG>, it is understood that any suitable number of signal paths <NUM> and/or <NUM> may be included within the probe <NUM> such that there may be L/<NUM> plurality of the conductors <NUM> within the probe <NUM>.

As shown in <FIG>, one end of the conductor <NUM> may be in communication with a switch <NUM>. In some embodiments, while an ultrasound imaging system <NUM> performs imaging other than CW Doppler, the switch <NUM> may be set to a position to engage the signal path <NUM> such that the ADC 220b may be in communication with the preamplifier <NUM> and the set 112b of transducer elements and is not in communication with the signal path <NUM> or the conductor <NUM>. When the ultrasound imaging system <NUM> is to image an area of interest within a patient using CW Doppler imaging, the switch <NUM> is actuated to establish communication with the conductor <NUM> and the signal path <NUM> as shown in <FIG>. In other words, the switch <NUM> establishes communication between circuitry 520a and circuitry 520b when the system <NUM> performs CW Doppler imaging. While performing CW Doppler imaging, the ultrasound imaging system <NUM> uses the transmitting set 112b of transducer elements to transmit acoustic waves as illustrated by the arrow <NUM>. In such a configuration, without the presence of the switches <NUM> or the conductors <NUM>, the ADCs 220b are unused. The switches <NUM> effectively combine the signal paths <NUM> with the signal paths <NUM> after the preamplifiers <NUM> to put the ADCs 220a and 220b in parallel such that a signal received by the receiving set 112a is converted from analog to digital using both the ADCs 220a and the ADCs 220b. This combining of signal paths increases the dynamic range of the ADCs by at least <NUM> dB. Additional switches and conductors similar to the switches <NUM> and conductors <NUM> may be present within the probe <NUM> and/or the host <NUM> so as to recombine signal paths.

In some embodiments, the circuitry <NUM> acts on the analog signals from the receiving portion of the array 112a to limit slew rate. Functionally, the circuity to limit the slew rate can be an op-amp that clips against the power rails (e.g., power signal line <NUM>) followed by an active low pass filter. This circuitry (and/or other circuitry of the block <NUM>) can be integrated within the probe <NUM> as an integrated circuit.

<FIG> is a graphical representation of a Doppler spectrum measured with an ultrasound imaging system, according to aspects of the present disclosure. The display <NUM> (<FIG>) may display to a user a Doppler spectrum similar to the Doppler spectrum <NUM>. Specifically, the Doppler spectrum <NUM> may be a depiction of data measured and processed using an ultrasound imaging system <NUM> with a probe similar to the probe <NUM> (<FIG>) including the limiters <NUM>, low pass filters <NUM>, switches <NUM>, and conductors <NUM>. As a result, while the Doppler spectrum <NUM> is similar to the Doppler spectrum <NUM> (<FIG>), the Doppler spectrum <NUM> also has differences. Specifically, the Doppler spectrum <NUM> may depict velocities of fluids and other objects but may include less sampling errors <NUM> due to increased dynamic range. Like the graphical representation of <FIG>, an axis in direction <NUM> along the Doppler spectrum <NUM> may indicate a time dimension. A direction <NUM> along Doppler spectrum <NUM> may indicate a velocity, which may correspond to the velocity of blood within the heart or a blood vessel of a patient. In some embodiments, the Doppler spectrum velocity may correspond to blood flow through a mitral valve within a heart. The values <NUM> depicted within the Doppler spectrum <NUM> may indicate the velocity of a fluid at a given location within a patient at a given time. The Doppler spectrum <NUM> may differ from the Doppler spectrum <NUM>, however, in that the Doppler spectrum <NUM> may include no or fewer sampling errors <NUM> of <FIG>. Sampling errors <NUM> may be significantly reduced or not present within the Doppler spectrum <NUM> in part due to effect that the limiters <NUM> and low pass filters <NUM> have on decreasing the dynamic range of received signals. Additionally, the Doppler spectrum <NUM> may not include, or include less, sampling errors <NUM> as a result of the switches <NUM> and conductors <NUM> increasing the overall dynamic range of the ADCs within the probe <NUM>.

Similar to the Doppler spectrum <NUM>, the Doppler spectrum <NUM> may be presented or depicted to a user in any suitable format. For example, the display <NUM> may additionally display multiple metrics associated with the Doppler spectrum <NUM> or corresponding to the anatomy of the patient.

The Doppler spectrum <NUM> of <FIG> additionally includes a number of regions <NUM>. The regions <NUM> may correspond to high velocities recorded and displayed to a user. These high velocities may correspond to leakage of various valves within a heart of a patient, or in any other suitable location within a vasculature of a patient. For example, a mitral valve within a patient's heart may not close completely and may leak, resulting in very high velocity jets of blood through a mitral valve when the valve is supposed to be closed while the heart pumps. The present invention is thus useful in diagnosing this or similar conditions within the heart or vasculature of a patient.

<FIG> is a schematic diagram of a processor circuit, according to aspects of the present disclosure. The processor circuit <NUM> may be implemented in the host <NUM>, probe <NUM> of <FIG>, or in any other suitable location. One or processor circuits <NUM> can be configured to perform the operations described herein. The processor circuit <NUM> can include additional circuitry or electronic components, such as those described herein. In an example, the processor circuit <NUM> may be in communication with the transducer array <NUM> in the probe <NUM>, circuitry <NUM>, the communication interface <NUM>, the communication interface <NUM>, circuitry <NUM>, and/or the display <NUM>, as well as any other suitable component or circuit within the ultrasound system <NUM> (<FIG>). As shown, the processor circuit <NUM> may include a processor <NUM>, a memory <NUM>, and a communication module <NUM>. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor <NUM> may include a CPU, a GPU, a DSP, an application-specific integrated circuit (ASIC), a controller, an FPGA, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

The memory <NUM> may include a cache memory (e.g., a cache memory of the processor <NUM>), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an embodiment, the memory <NUM> includes a non-transitory computer-readable medium. The instructions <NUM> may include instructions that, when executed by the processor <NUM>, cause the processor <NUM> to perform the operations described herein with reference to the probe <NUM> and/or the host <NUM> (<FIG>). Instructions <NUM> may also be referred to as code. The terms "instructions" and "code" should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms "instructions" and "code" may refer to one or more programs, routines, sub-routines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or many computer-readable statements.

The communication module <NUM> can include any electronic circuitry and/or logic circuitry to facilitate direct or indirect communication of data between the processor circuit <NUM>, the probe <NUM>, and/or the display. In that regard, the communication module <NUM> can be an input/output (I/O) device. In some instances, the communication module <NUM> facilitates direct or indirect communication between various elements of the processor circuit <NUM> and/or the probe <NUM> (<FIG>) and/or the host <NUM> (<FIG>).

<FIG> is a flow diagram of a ultrasound imaging method <NUM>, according to aspects of the present disclosure. One or more steps of the method <NUM> can be performed by a processor circuit of the ultrasound imaging system <NUM>, including, e.g., the processor <NUM> (<FIG>). As illustrated, method <NUM> includes a number of enumerated steps, but embodiments of method <NUM> may include additional steps before, after, or in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted, performed in a different order, or performed concurrently. The steps of method <NUM> can be carried out by any suitable component within ultrasound imaging system <NUM> and all steps need not be carried out by the same component.

At step <NUM>, the method <NUM> includes generating analog ultrasound signals. Command signals may be generated at the host <NUM> and transmitted to the probe <NUM> via the signal line <NUM>. The pulsers <NUM> may consequently generate a signal to excite the transmitting set 112b of transducer elements to generate ultrasound waves (<FIG>). The transducers of the receiving set 112a may then receive echo signals reflected from features in the patient's anatomy and generate analog electrical signals representative of the ultrasound echoes. The generated analog ultrasound signals may then be transmitted to the circuitry 520a (<FIG>).

At step <NUM>, the method <NUM> includes limiting the slew rate of the analog signals so as to not over drive the analog to digital convertor, eliminating artifacts associated with motion and jitter. In some embodiments, the slew rate of the analog signals may be limited within the probe to match or not exceed the slew rate that can be handled by ADC <NUM> (<FIG>) or any other component within the probe <NUM> or the system <NUM> such that artifacts in the graphical representations of blood flow velocities over cardiac cycles are advantageously avoided.

At step <NUM>, the method <NUM> includes converting analog ultrasound signals to digital ultrasound signals. As shown previously, reflected ultrasound energy may be optionally reduced via the analog beamformer <NUM>. Analog signals corresponding to reflected waves may then be transmitted to the ADCs <NUM>, 220a, or 220b to be converted from analog ultrasound signals to digital ultrasound signals. Digital signals may then be further beamformed, multiplexed, or otherwise combined via the combiner <NUM> of <FIG>, or any other suitable component before being transmitted to the host <NUM> via the cable <NUM>. In some embodiments, digital ultrasound signals may be beamformed and/or otherwise combined via the combiner <NUM> located within the host <NUM> as shown in <FIG>.

At step <NUM>, the method <NUM> includes generating digital CW Doppler signals based on the digital ultrasound signals. CW Doppler signals may be generated via any suitable method based on the received digital ultrasound waves. For example, digital I/Q mixers can receive the digital ultrasound signals and generate the digital CW Doppler signals within the host <NUM>.

At step <NUM>, the method <NUM> includes processing the digital CW Doppler signals. Processing of the digital CW Doppler signals may include any suitable data processing component or procedure, including filtering via low pass filters, high pass filters or any suitable type of filter. Data processing may additional include windowing, summations, averaging, smoothing, transformations from one domain to another, such as fast Fourier transforms, and any other suitable conditioning to improve the overall data quality, clarity, or presentation. In addition, digital signal processing may be done via a processor, in software form, or with hardware, such as with physical circuitry within the host <NUM> or via any other suitable method or form.

At step <NUM>, the method <NUM> includes generating graphical representations of blood flow velocities over cardiac cycles. The graphical representations may include any suitable means of data presentation. For example, graphical representations may include lists of data including time, velocities, dimensions, or data relating to the location of an imaged object within a patient's anatomy. Graphical representations may additionally include a Doppler spectrum similar to those depicted in <FIG> and/or <FIG>. The graphical representations may also include any suitable plots, pictures, or depictions which may convey to a user information regarding the health or physical state of a patient. The graphical representations may also include any of the previously mentioned metrics relating to a patient's anatomy or a CW Doppler graph.

At step <NUM>, the method <NUM> includes outputting the graphical representations of blood flow velocities over cardiac cycles to a display. Any of the previously mentioned graphical representations may be output to a display <NUM>. Such graphical representations may be displayed in real time, as a sonographer conducts an ultrasound examination, or may be displayed at a later time. The graphical representations generated by the ultrasound imaging system <NUM> may be stored in the memory <NUM> in connection with the processor circuit <NUM> or may be stored on a cloud-based server or similar device. Any suitable metric associated with a patient's health or physical state either based on data collected with the ultrasound imaging system <NUM> or otherwise obtained with other equipment or procedures or from various different examinations at different times may also be displayed to a user accompanying any graphical representations.

<FIG> is a schematic diagram illustrating an example ultrasound transducer array <NUM>, according to aspects of the present disclosure. The ultrasound transducer array <NUM> includes multiple ultrasound transducers <NUM> arranged into sub-arrays <NUM>.

The transducer array <NUM> shown in <FIG> may be a <NUM>. X-dimensional or two-dimensional matrix of ultrasound elements <NUM>. The transducer array <NUM> may be substantially similar to the transducer array <NUM> of <FIG> and/or <FIG>. In other embodiments, the transducer array <NUM> may also be a <NUM>-dimensional linear array, or any other suitable type of array. As previously mentioned in regards to the transducer array <NUM>, the transducer array <NUM> may include any suitable number of transducer elements <NUM>. The transducer elements <NUM> may be arranged within transducer array <NUM> in multiple sub-arrays <NUM>. The sub-arrays <NUM> may additionally be referred to as groups or patches, among other suitable terms. Each sub-array <NUM> may include four transducer elements <NUM>, or any other suitable number of transducer elements <NUM>. For example, the sub-array <NUM> may comprise <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more transducer elements <NUM> as well as any suitable number therebetween. In addition, in some embodiments, each sub-array <NUM> need not include the same number of transducer elements <NUM>, but each could vary according to any suitable arrangement or pattern. It is noted that the spacing between sub-arrays <NUM> shown in <FIG> does not necessarily indicate physical spacing or separation within the array. For example, each of the transducer elements in the array can have the same space with each adjacent element (whether or not that element is part of the same sub-array). Rather, the spacing shown in <FIG> can be illustrative of the sub-array groupings.

<FIG> is a schematic diagram illustrating example circuitry of an analog beamformer <NUM>, according to aspects of the present disclosure. The analog beamformer <NUM> may be substantially similar to the analog beamformer <NUM> of <FIG>. <FIG> provides a more detailed view of the analog beamformer <NUM>, which may be implemented within the ultrasound probe. The analog beamformer <NUM> includes multiple transmit pulsers <NUM>, preamplifiers <NUM>, delay circuits <NUM>, a summation component <NUM>, and conductors <NUM> providing power, clock, and/or control signals to any of these components. <FIG> additionally depicts one sub-array <NUM> including multiple ultrasound transducer elements <NUM>. The sub-array <NUM> shown in <FIG> may be one of the sub-arrays <NUM> shown in <FIG> or may be a different sub-array.

The transmit pulsers <NUM> may be substantially similar to the pulsers <NUM> of <FIG>. Specifically, the transmit pulsers <NUM> may receive command signals from the host and in response to these command signals, transmit high-voltage pulses to activate the ultrasound elements <NUM> to emit ultrasound energy that propagates into a patient's anatomy. Each ultrasound element <NUM> may therefore correspond to and/or be in communication with a transmit pulser <NUM>.

Multiple preamplifiers <NUM> are additionally depicted in <FIG>. The preamplifiers <NUM> may be substantially similar to the preamplifiers <NUM> of <FIG>. The preamplifiers <NUM> may amplify signals received from the ultrasound elements <NUM> to improve the quality of received signals by, for example, reducing a noise floor.

Multiple delay circuits <NUM> may be in communication with the preamplifiers <NUM> within the analog beamformer <NUM>. The delay circuits <NUM> may be of any suitable type. For example, the delay circuits <NUM> may include analog delay circuitry for the analog beamformer <NUM>. The delay circuits <NUM> may apply a delay profile to signals received from the ultrasound transducers <NUM> so as to perform beamforming in relation to all elements within a sub-array <NUM> or partial beamforming. Such delay profiles may be provided to the delay circuits <NUM> via any suitable method. For example, in some embodiments, a conductor corresponding to control or clock data within the conductors <NUM> may be in communication with the delay circuits <NUM> and may dictate delay profiles for the delay circuits <NUM>.

<FIG> additionally depicts a summation component <NUM>. The summation component <NUM> may be an analog adder circuit, summing mixer, or any suitable electronic component for summing signals. The summation component <NUM> is in communication with the respective outputs of the delay circuits <NUM>. In such a configuration, the signals output from each delay circuit <NUM> may be summed in an analog fashion. In other embodiments, the summation component <NUM> may comprise any suitable circuitry or configuration to otherwise combine signals from the outputs of the delay circuits <NUM>. The output of the summation component <NUM> may then be in communication with one or more T/R switches <NUM> from <FIG> and the signals combined by the analog beamformer <NUM> may be further processed and/or combined within the probe <NUM> and/or the host <NUM> as has been described or in any other suitable way.

Claim 1:
An ultrasound system, comprising:
a transducer array configured to generate continuous analog ultrasound signals, wherein the transducer array comprises at least a first acoustic element and a second acoustic element;
a first analog-to-digital converter, ADC, (220a) in communication and associated with the first acoustic element of the transducer array (112a), wherein the first ADC is configured to convert analog ultrasound signals received from the first acoustic element to first digital ultrasound signals;
a second ADC (220b) associated with the second acoustic element of the transducer array (112b), wherein the second ADC is configured to convert analog ultrasound signals received from the second acoustic element to second digital ultrasound signals;
a switch (<NUM>) configured to establish communication selectively between the second ADC and the first acoustic element or the second acoustic element, wherein the switch establishes communication between the second ADC and the first acoustic element when the second acoustic element is a transmit element and the first acoustic element is a receive element such that the analog ultrasound signals received from the first acoustic element are converted to third digital ultrasound signals using both the first ADC and the second ADC; and
a processor circuit (<NUM>) in communication with the ADCs, wherein the processor circuit comprises digital in-phase/quadrature, I/Q, mixers configured to generate digital continuous wave, CW, Doppler signals based on the third digital ultrasound signals, and wherein the processor circuit is configured to:
process the digital CW Doppler signals;
generate a graphical representation of a distribution of blood flow velocities; and
output the graphical representation to a display in communication with the processor circuit.