Patent Publication Number: US-2022233166-A1

Title: Distributed portable ultrasound system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 16/240,425, filed Jan. 4, 2019, for DISTRIBUTED PORTABLE ULTRASOUND SYSTEM, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to distributed ultrasound imaging systems. Specifically, this disclosure relates to distributing processing between a portable system of a distributed ultrasound imaging system and an external ultrasound docking unit of the distributed ultrasound imaging system, e.g. for providing high-performance ultrasound image processing. 
     BACKGROUND OF THE INVENTION 
     Ultrasound systems have continued to advance in channel count, image processing and portability. The requirement for greater portability has been at odds with systems with high channel count and high-performance image processing capabilities, e.g. 3D TEE, 3D TTE, and other high computational demand processes. Specifically, the increased computational resources needed for functioning according to high-performance image processing capabilities can make portable ultrasounds incapable for portable operation. More specifically, providing high-performance image processing capabilities can increase needed computational resources and power for performing such high-performance processes in a real time manner at a high level of quality. In turn, these increased demands for computational resources and computational power can further burden the size, weight, battery life, cooling, and the like of components in a portable ultrasound system. There therefore, exist needs for portable ultrasound systems and processing methods that allow for high-performance ultrasound processing in a portable ultrasound system. 
     Further, typical ultrasound systems contain a substantial amount of proprietary hardware. The performance of this proprietary hardware is what typically differentiates the performance characteristics of these systems. Over the years, the amount of proprietary hardware contained within ultrasound systems has steadily decreased, however some current systems still include proprietary hardware. Proprietary hardware in ultrasound systems can limit the incorporation of industry advances in both hardware and processing methods, e.g. made in the ultrasound industry and other industries, into such ultrasound systems. For example, advances in parallel processing components made in the gaming industry are not easily adaptable for ultrasound systems as typical ultrasound systems utilize proprietary hardware. There therefore, exist needs for portable ultrasound systems and processing methods that are compatible with advances in hardware and processing methods, e.g. from both the ultrasound industry and other industries, in order to achieve high-performance ultrasound processing in a portable ultrasound system. 
     SUMMARY 
     In various embodiments, a distributed ultrasound system includes a portable ultrasound system and an external ultrasound docking unit. The portable ultrasound system can include one or more transmitters configured to transmit ultrasound waves into a subject region. Further, the portable ultrasound system can include one or more receivers configured to receive ultrasound waves from the subject region in response to the ultrasound waves transmitted into the subject region. Additionally, the portable ultrasound system can include a portable ultrasound processing unit configured to perform ultrasound image processing for generating one or more ultrasound images of the subject region using the ultrasound waves received by the one or more receivers. The external ultrasound docking unit is configured to receive the portable ultrasound system and offload at least a portion of the ultrasound image processing from the portable ultrasound system when the portable ultrasound system is coupled to the external ultrasound docking unit. 
     In certain embodiments, a portable ultrasound system is provided to a user. The portable ultrasound system can include one or more transmitters configured to transmit ultrasound waves into a subject region. Further, the portable ultrasound system can include one or more receivers configured to receive ultrasound waves from the subject region in response to the ultrasound waves transmitted into the subject region. Additionally, the portable ultrasound system can include a portable ultrasound processing unit configured to perform ultrasound image processing for generating one or more ultrasound images of the subject region using the ultrasound waves received by the one or more receivers. Additionally, an external ultrasound docking unit is provided. The external ultrasound docking unit can be configured to receive the portable ultrasound system and offload at least a portion of the ultrasound image processing from the portable ultrasound system when the portable ultrasound system is coupled to the external ultrasound docking unit. 
     In various embodiments, a portable ultrasound system is coupled to an external ultrasound docking unit. The portable ultrasound system can be configured to receive ultrasound waves from a subject region in response to ultrasound waves transmitted into the subject region. The portable ultrasound system can also be configured to generate one or more ultrasound images of the subject region through ultrasound image processing using the ultrasound waves received from the subject region. Further, at least a portion of the ultrasound image processing can be offloaded from the portable ultrasound system to the external ultrasound docking unit to generate the one or more ultrasound images. Specifically, the at least the portion of the ultrasound image processing can be offloaded to the external ultrasound docking unit through the coupling of the portable ultrasound system to the external ultrasound docking unit in order to generate the one or more ultrasound images. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example of an ultrasound system. 
         FIG. 2  shows an example distributed ultrasound system. 
         FIG. 3  shows a block diagram of a distributed ultrasound system with an expansion communication bus for enhanced image processing capabilities. 
         FIG. 4  shows a block diagram of another distributed ultrasound system with an expansion communication bus for enhanced image formation and image processing capabilities. 
         FIG. 5  shows a block diagram of a system including a signal bus between a portable ultrasound system and expansion slots of an external docking unit, e.g. an ultrasound cart. 
         FIG. 6  is a flowchart of an example method of providing a distributed ultrasound system configured to offload processing from a portable ultrasound system in the distributed ultrasound system. 
         FIG. 7  is a flowchart of an example method of offloading processing from a portable ultrasound system in a distributed ultrasound system. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure relates to the need in the art for portable ultrasound systems that can be used to provide high-performance ultrasound image processing. Specifically, the disclosure relates to systems, methods, and computer-readable media for distributing ultrasound image processing between a portable ultrasound system and an external ultrasound docking unit to provide high-performance ultrasound image processing. 
     Ultrasound systems have continued to advance in channel count, image processing and portability. As ultrasound systems have continued to advance, the desire for greater portability has been at odds with systems with high channel count and high-performance image processing capabilities. Specifically, when a portable ultrasound system is operated in hand, e.g. separate from an ultrasound cart/docking unit, basic ultrasound image processing operations can be performed. For example, 2D, Color Doppler, PW-Doppler, CEUS, M-Mode, CW-Doppler, biplane exams and the like low-performance image processing exams can be performed when a portable ultrasound system is operated separate from or otherwise detached from a cart. Conversely, when a portable ultrasound system is docked in a cart/docking unit, high performance ultrasound image processing operations can be performed. For example, exams like 3D TEE, 3D TTE and the like high-performance ultrasound image processing exams can be performed when a portable ultrasound system is docked in a cart. 
     Such high-performance ultrasound image processing exams can require a substantial amount of additional processing power to perform in a real time manner at a high level of quality. Specifically, these high-performance ultrasound image processing exams require a greater amount of processing power to perform than an amount of processing power needed to perform low-performance imaging processing operations/exams. This additional image processing power, if included in the hand carried portable ultrasound system, can provide additional burdens on one or a combination of the size, weight, battery life, cooling and the like, making a portable ultrasound system capable of performing high-performance ultrasound image processing unpractical. However, this extra processing power is not required when the portable ultrasound system is operated in hand, but only when the system is docked in the cart. Therefore, a distributed processing system is needed that has the capabilities to enhance the image processing capabilities of a portable ultrasound system when it is docked in a cart. Further, there exist needs for a distributed processing system that does not hinder operation of a portable ultrasound system when it is operated in hand, e.g. undocked from a cart. 
     Additionally, ultrasound systems have been constructed with a substantial amount of proprietary hardware. Specifically, the overall performance of the hardware implemented in ultrasound systems can differentiate the performance characteristics of those systems. Over the years the amount of proprietary hardware contained within a system has steadily decreased and currently a number of systems contain no proprietary hardware at all. These systems differentiate themselves on their basic architecture, algorithms and processing power. Typically, newer designed systems have the ability to take advantage in processing power from other industries like; gaming, scientific computing, virtual reality/augmented reality and the like, so that they contain substantially more processing power than the early systems. Further, as these ultrasound systems can borrow technological advances from other industries, their basic electronics outside the increased processing power change only very little. 
     Further, the custom architecture in ultrasound systems can also be dictated by the required signal bandwidth being higher than industry standard bus architectures. Over the years this gap has also closed to the point that current industry standard bus architectures have sufficient bandwidth to alleviate the need for custom architectures. This is also another step that has enabled the simplification of the basic ultrasound architecture and enabled industry standards to be used for communications between most if not all of the modules within ultrasound systems. 
     A number of the processing advancements have been achieved with using more parallel processors and the incorporation of optimized arithmetic blocks in programmable logic. Specifically, parallel processors have been exploited in Graphical Processing Units (GPUs), Digital Signal Processors (DSPs), Central Processing Units (CPUs), while the optimized arithmetic blocks have been incorporated in Field Programmable Gate Arrays (FPGAs). The exploitation of being able to replicate existing designs in parallel with minimum changes along with an on-chip optimized communication bus can enable such ultrasound systems to improve in performance in at a steady pace. In particular these systems can improve at a steady pace while the chips that have relied on continually higher clock frequencies have reached a plateau and the chip performance improves are at a much slower pace. Unfortunately, as these devices continue to drive to higher and higher performance, the system requirements in power and cooling continue to be significant. Specifically, the industry has optimized for maximizing performance and pushed the design limits to the maximum power and heat dissipation possible to achieve performance goals. These high levels of power and heat pose an issue when these devices are desired to be used in a portable ultrasound system that is battery operated. Specifically, in order to meet power and heat dissipation requirements, the industry has had to utilize older generation devices that operate at a substantially lower level of performance but also consume less power and require less cooling. 
     Given that portable ultrasound systems are rarely taken from the carts they are docked into, there is the potential to still maintain a portable ultrasound system capable of integration with a system for performing high-performance ultrasound image processing away from the cart. Specifically, the portable ultrasound systems can be configured to provide high-performance ultrasound image processing when integrated with the carts, as the carts provide improved storage capacity, the ability to connect multiple transducers, print capabilities, expanded connectivity, along with potentially additional battery capacity for being able to power the system without the need to plug into the electrical outlet. Specifically, the overall processing performance of distributed ultrasound systems including portable ultrasound systems can be augmented while it is docked into the cart. 
     More specifically, when the portable ultrasound system is docked in a cart, it is desirable that the system connect to the cart through an expansion bus, e.g. potentially automatically. This can enable the portable ultrasound system to be able to have augmented performance capabilities from both battery operation as well as processing. A typical communication bus can be, for example, a PCIe Version 5.0 with  16  lanes to have a transfer rate of over 32 GB/sec, which is more than sufficient to handle both the backend image processing requirements but also sufficient to benefit image formation capabilities as well. The benefits of using an industry standard bus architecture is that an off the shelf processing module can be used. There are several groups that make these modules, such as nVidia®, Texas Instruments®, Intel®, Xilinx® and the like. The challenge of these off the shelf processing cards is that they take up more space as well as consume a substantial amount of power to operate as compared to the processors that contained within portable ultrasound systems. The advantage is that these off the shelf processors offer the best performance as well as can be cost effectively exchanged as new technology becomes available without substantial additional costs for the product, design, or regulatory. It should be easily understood to anyone skilled in the art that just using a bus expansion as well as added battery capabilities is only a few of the features that can be offloaded to the cart for augmented performance. For example, other features that have performance/user experiences capable of being augmented by the cart/docking unit are as following: display, user interface, external connectivity, digital storage, and the like. 
     In various embodiments, a distributed ultrasound system includes a portable ultrasound system and an external ultrasound docking unit. The portable ultrasound system can include one or more transmitters configured to transmit ultrasound waves into a subject region. Further, the portable ultrasound system can include one or more receivers configured to receive ultrasound waves from the subject region in response to the ultrasound waves transmitted into the subject region. Additionally, the portable ultrasound system can include a portable ultrasound processing unit configured to perform ultrasound image processing for generating one or more ultrasound images of the subject region using the ultrasound waves received by the one or more receivers. The external ultrasound docking unit is configured to receive the portable ultrasound system and offload at least a portion of the ultrasound image processing from the portable ultrasound system when the portable ultrasound system is coupled to the external ultrasound docking unit. 
     In certain embodiments, a portable ultrasound system is provided to a user. The portable ultrasound system can include one or more transmitters configured to transmit ultrasound waves into a subject region. Further, the portable ultrasound system can include one or more receivers configured to receive ultrasound waves from the subject region in response to the ultrasound waves transmitted into the subject region. Additionally, the portable ultrasound system can include a portable ultrasound processing unit configured to perform ultrasound image processing for generating one or more ultrasound images of the subject region using the ultrasound waves received by the one or more receivers. Additionally, an external ultrasound docking unit is provided. The external ultrasound docking unit can be configured to receive the portable ultrasound system and offload at least a portion of the ultrasound image processing from the portable ultrasound system when the portable ultrasound system is coupled to the external ultrasound docking unit. 
     In various embodiments, a portable ultrasound system is coupled to an external ultrasound docking unit. The portable ultrasound system can be configured to receive ultrasound waves from a subject region in response to ultrasound waves transmitted into the subject region. The portable ultrasound system can also be configured to generate one or more ultrasound images of the subject region through ultrasound image processing using the ultrasound waves received from the subject region. Further, at least a portion of the ultrasound image processing can be offloaded from the portable ultrasound system to the external ultrasound docking unit to generate the one or more ultrasound images. Specifically, the at least the portion of the ultrasound image processing can be offloaded to the external ultrasound docking unit through the coupling of the portable ultrasound system to the external ultrasound docking unit in order to generate the one or more ultrasound images. 
     Some of the infrastructure that can be used with embodiments disclosed herein is already available, such as general-purpose computers, computer programming tools and techniques, digital storage media, and communications networks. A computing device may include a processor such as a microprocessor, microcontroller, logic circuitry, or the like. The processor may include a special purpose processing device such as an ASIC, PAL, PLA, PLD, FPGA, or other customized or programmable device. The computing device may also include a computer-readable storage device such as non-volatile memory, static RAM, dynamic RAM, ROM, CD-ROM, disk, tape, magnetic, optical, flash memory, or other computer-readable storage medium. 
     Various aspects of certain embodiments may be implemented using hardware, software, firmware, or a combination thereof. As used herein, a software module or component may include any type of computer instruction or computer executable code located within or on a computer-readable storage medium. A software module may, for instance, comprise one or more physical or logical blocks of computer instructions, which may be organized as a routine, program, object, component, data structure, etc., that performs one or more tasks or implements particular abstract data types. 
     In certain embodiments, a particular software module may comprise disparate instructions stored in different locations of a computer-readable storage medium, which together implement the described functionality of the module. Indeed, a module may comprise a single instruction or many instructions, and may be distributed over several different code segments, among different programs, and across several computer-readable storage media. Some embodiments may be practiced in a distributed computing environment where tasks are performed by a remote processing device linked through a communications network. 
     The embodiments of the disclosure will be best understood by reference to the drawings. The components of the disclosed embodiments, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Furthermore, the features, structures, and operations associated with one embodiment may be applicable to or combined with the features, structures, or operations described in conjunction with another embodiment. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of this disclosure. 
     Thus, the following detailed description of the embodiments of the systems and methods of the disclosure is not intended to limit the scope of the disclosure, as claimed, but is merely representative of possible embodiments. In addition, the steps of a method do not necessarily need to be executed in any specific order, or even sequentially, nor need the steps be executed only once. 
       FIG. 1  illustrates an example of an ultrasound system  100 . The ultrasound system  100  shown in  FIG. 1  is merely an example system and in various embodiments, the ultrasound system  100  can have less components or additional components. The ultrasound system  100  can be an ultrasound system where the receive array focusing unit is referred to as a beam former  102 , and image formation can be performed on a scanline-by-scanline basis. System control can be centered in the master controller  104 , which accepts operator inputs through an operator interface and in turn controls the various subsystems. For each scan line, the transmitter  106  generates a radio-frequency (RF) excitation voltage pulse waveform and applies it with appropriate timing across the transmit aperture (defined by a sub-array of active elements) to generate a focused acoustic beam along the scan line. RF echoes received by the receive aperture  108  of the transducer  110  are amplified and filtered by the receiver  108 , and then fed into the beam former  102 , whose function is to perform dynamic receive focusing; i.e., to re-align the RF signals that originate from the same locations along various scan lines. 
     The image processor  112  can perform processing specific to active imaging mode(s) including 2D scan conversion that transforms the image data from an acoustic line grid to an X-Y pixel image for display. For Spectral Doppler mode, the image processor  112  can perform wall filtering followed by spectral analysis of Doppler-shifted signal samples using typically a sliding FFT-window. The image processor  112  can also generate the stereo audio signal output corresponding to forward and reverse flow signals. In cooperation with the master controller  104 , the image processor  112  also can format images from two or more active imaging modes, including display annotation, graphics overlays and replay of cine loops and recorded timeline data. 
     The cine buffer  114  provides resident digital image storage for single image or multiple image loop review, and acts as a buffer for transfer of images to digital archival devices. On most systems, the video images at the end of the data processing path can be stored to the cine memory. In state-of-the-art systems, amplitude-detected, beamformed data may also be stored in cine memory  114 . For spectral Doppler, wall-filtered, baseband Doppler 1/Q data for a user-selected range gate can be stored in cine memory  114 . Subsequently, the display  116  can display ultrasound images created by the image processor  112  and/or images using data stored in the cine memory  114 . 
     The beam former  102 , the master controller  104 , the image processor, the cine memory  114 , and the display can be included as part of a main processing console  118  of the ultrasound system  100 . In various embodiments, the main processing console  118  can include more or fewer components or subsystems. The ultrasound transducer  110  can be incorporated in an apparatus that is separate from the main processing console  118 , e.g. in a separate apparatus that is wired or wirelessly connected to the main processing console  118 . This allows for easier manipulation of the ultrasound transducer  110  when performing specific ultrasound procedures on a patient. Further, the transducer  110  can be an array transducer that includes an array of transmitting and receiving elements for transmitting and receiving ultrasound waves. 
       FIG. 2  shows an example distributed ultrasound system  200 . The distributed ultrasound system  200  shown in  FIG. 2  can be configured to perform the functionalities of an applicable ultrasound system, such as the ultrasound system  100  shown in  FIG. 1 . Specifically, the distributed ultrasound system  200  can be configured to implement both high-performance ultrasound image processing and low-performance ultrasound image processing. For example, the distributed ultrasound system  200  can perform both PW Doppler imaging and 3D TEE imaging. 
     The distributed ultrasound system  200  includes a portable ultrasound system  202  and an external ultrasound docking unit  204 . The portable ultrasound system  202  functions, at least in part, to generate ultrasound images according to an applicable ultrasound system, such as the ultrasound system  100  shown in  FIG. 1 . Specifically, the portable ultrasound system  202  can include one or more transmitter(s)  208  and one or more receiver(s)  210 . In operation, the transmitter(s)  208  and the receiver(s)  210  can function to transmit ultrasound waves into a subject region and receive ultrasound waves from the subject region in response to the ultrasound waves transmitted into the subject region. Specifically, the transmitter(s)  208  and the receiver(s)  210  can function according to an applicable ultrasound transducer, such as the ultrasound transducer  110  shown in  FIG. 1 . 
     Further, the portable ultrasound system  202  includes a portable ultrasound processing unit  212 . The portable ultrasound processing unit  212  functions to perform ultrasound image processing for generating one or more ultrasound images from ultrasound waves received by the receiver(s)  210 . Specifically, the portable ultrasound processing unit  212  can perform ultrasound image processing on ultrasound waves received in response to ultrasound waves transmitted into a subject region by the transmitter(s)  208 . The portable ultrasound processing unit  212  can perform applicable ultrasound image processing, such as the functionalities performed by the main processing console  118 . Ultrasound image processing, as used herein, can include applicable operations applied to generate one or more ultrasound images. Specifically, ultrasound image processing can include operations for generating beamformed data from channel domain data and operations for processing post-beamformed/beamformed data to generate one or more ultrasound images. Specifically, ultrasound image processing performed by the portable ultrasound processing unit  212  can include basic/low-performance ultrasound image processing operations. For example, the portable ultrasound processing unit  212  can perform operations such as portable 2D, Color Doppler, PW-Doppler, CEUS, M-Mode, CW-Doppler, biplane exams, and the like low-performance image processing exams. 
     Additionally, the portable ultrasound processing unit  212  can apply applicable backend/post-processing techniques to ultrasound images, as part of performing ultrasound image processing. Specifically, the portable ultrasound processing unit  212  can apply backend processing to ultrasound images that are generated by the portable ultrasound processing unit  212 . Backend processing, can include applicable image processing techniques for preparing ultrasound images for display. For example, the portable ultrasound processing unit  212  can perform, as part of backend processing, up sampling, down sampling, log compression, detection, spatial filtering, adaptive filtering, scan conversion, and the like, for displaying images. 
     The portable ultrasound system  202  may include a variety of additional components, including, without limitation, a processor  214  to control and coordinate the operations of the portable ultrasound system  202 , a battery  216  to provide power to the system  202 , a battery-level sensor  218  to measure a charging level of the battery  216 , a temperature sensor  220  to measure the temperature of the system  202  and/or individual components thereof (e.g., processor  214 , battery  216 ), a display  222  to display ultrasound images and other information (e.g., user interfaces, alerts), and a communication interface  224 . These components will be described in greater detail below. 
     The portable ultrasound system  202  is portable in that it can be moved by a user during operation. Specifically, the portable ultrasound system  202  can be handheld. In turn, an operator can manipulate, e.g. move, the portable ultrasound system  202  over a patient&#39;s body to an area proximate to a subject region and perform an exam or otherwise gather data and generate ultrasound images including the subject region. Further, in being portable, the portable ultrasound system  202  can be removable secured to the external ultrasound docking unit  204 . Specifically, the portable ultrasound system  202  can be physically detached from the external ultrasound docking unit  204  when it is operated in a portable manner. 
     The portable ultrasound system  202  can be coupled to the external ultrasound docking unit  204  through a docking connection  206 . The docking connection  206  can be formed by either or both a physical connection and an electrical connection and may be provided using the communication interface  224  in some embodiments. In other embodiments, the communication interface  224  may be separate from the docking connection  206  and may be used for communicating with a network, such as the Internet. For example, the docking connection  206  can electrically couple the portable ultrasound system  202  to the external ultrasound docking unit  204  through either or both a wired or a wireless connection. In another example, the docking connection  206  can physically secure the portable ultrasound system  202  to the external ultrasound docking unit  204 . 
     In various embodiments, the portable ultrasound system  202  can be moved separate from, e.g. be physically detached from, the external ultrasound docking unit  204  while the portable ultrasound system  202  is electrically coupled to the external ultrasound docking unit  204 . For example, the portable ultrasound system  202  can be physically detached from the external ultrasound docking unit  204  while it is still electrically connected to the external ultrasound docking unit  204  through a wired connection. In turn, the docking connection  206  can be used to transmit data, e.g. beamformed ultrasound data, to the external ultrasound docking unit  204  from the portable ultrasound system  202  as the portable ultrasound system  202  is manipulated during operation. 
     The docking connection  206  can be formed by a communication bus. In being formed by a communication bus, the docking connection  206  can provide data input and data output between the portable ultrasound system  202  and the external ultrasound docking unit  204 . For example, raw ultrasound data gathered by the portable ultrasound system  202  can be transferred to the external ultrasound docking unit  204  through a communication bus. Subsequently, and as will be discussed in greater detail later, the external ultrasound docking unit  204  can apply ultrasound image processing to the raw ultrasound data to generate ultrasound images. Further, in being formed by a communication bus, the docking connection  206  can be used to transfer power between the portable ultrasound system  202  and the external ultrasound docking unit  204 . 
     In various embodiments, the docking connection  206  can be formed using industry standard/off-the-shelf connection hardware and coupling mechanisms. Specifically, a communication bus forming the docking connection  206  can be an industry standard communication bus. This can allow for easy integration of the distributed ultrasound system  200  with industry standard ultrasound image processing techniques. Further, this can allow for easy integration of the distributed ultrasound system  200  with industry standard computer processing hardware and techniques. For example, using a communication bus that is standard in the gaming industry can facilitate integration of gaming industry hardware and processing techniques into the distributed ultrasound system  200 . This is advantageous as advances in processing hardware and techniques have been developed further in other industries separate from the ultrasound industry. 
     The external ultrasound docking unit  204  functions to receive the portable ultrasound system  202 . In receiving the portable ultrasound system  202 , the external ultrasound docking unit  204  can be physically and electrically coupled to the portable ultrasound system  202 . Specifically, the portable ultrasound system  202  can be physically docked to the external ultrasound docking unit  204  by an operator, e.g. through docking connection  206 . More specifically, concurrently with physically docking the portable ultrasound system  202  to the external ultrasound docking unit  204 , the portable ultrasound system  202  can be automatically electrically coupled to the external ultrasound docking unit  204 . For example, the portable ultrasound system  202  can be physically secured to the external ultrasound docking unit  204  through a mechanical structure that includes a communication bus that automatically electrically connects the portable ultrasound system  202  to the external ultrasound docking unit  204  when the portable ultrasound system  202  is physically secured to the external ultrasound docking unit  204 . Alternatively, the portable ultrasound system  202  can be manually electrically connected to the external ultrasound docking unit. For example, the portable ultrasound system  202  can be physically connected to the external ultrasound docking unit  204  and a user can manually connect the portable ultrasound system  202  to an input/output port to electrically connect the portable ultrasound system  202  to the external ultrasound docking unit  204 . 
     Additionally, the external ultrasound docking unit  204  functions to offload ultrasound image processing from the portable ultrasound system  202 . The external ultrasound docking unit  204  can perform applicable ultrasound image processing, as part of offloading ultrasound image processing from the portable ultrasound system  202 . Specifically, the external ultrasound docking unit  204  can perform the functionalities carried out by the main processing console  118 . Further, ultrasound image processing performed by the external ultrasound docking unit  204  can include operations for generating beamformed data from channel domain data and operations for processing beamformed data to generate one or more ultrasound images. Specifically, ultrasound image processing performed by the external ultrasound docking unit  204  can include high-performance ultrasound image processing operations. For example, the external ultrasound docking unit  204  can perform operations such as 3D TEE, 3D TTE, and other high computational demand processes. 
     In offloading ultrasound image processing from the portable ultrasound system  202 , the external ultrasound docking unit  204  can perform ultrasound image processing that the portable ultrasound processing unit  212  is unable to perform, e.g. lacks the computational resources and processing power to perform. Specifically, the external ultrasound docking unit  204 , as will be discussed in greater detail later, can have a greater amount of processing power than the portable ultrasound processing unit  212 . In turn, the external ultrasound docking unit  204  can be configured to perform operations that require a greater amount of computational resources than the computational resources available at the portable ultrasound processing unit  212 . For example, the external ultrasound docking unit  204  can perform 3D ultrasound image processing if the portable ultrasound processing unit  212  lacks the processing power to perform 3D ultrasound image processing. Alternatively, the external ultrasound docking unit  204  can be configured to perform ultrasound image processing that the portable ultrasound processing unit  212  is able to perform, but is still offloaded to the external ultrasound docking unit  204 . 
     Additionally, in offloading ultrasound image processing from the portable ultrasound system  202 , the external ultrasound docking unit  204  can receive, from the portable ultrasound system  202 , channel domain data gathered by the portable ultrasound system  202 . Subsequently, the external ultrasound docking unit  204  can apply operations to the channel domain data to generate one or more ultrasound images. For example, the external ultrasound docking unit  204  can apply applicable beamforming operations to channel domain data to generate beamformed data as part of generating ultrasound images. 
     Further, in offloading ultrasound image processing from the portable ultrasound system  202 , the external ultrasound docking unit  204  can receive, from the portable ultrasound system  202 , beamformed data generated by the portable ultrasound processing unit  212 . Subsequently, the external ultrasound docking unit  204  can apply operations to the beamformed data to ultimately generate one or more ultrasound images. 
     The external ultrasound docking unit  204  can apply applicable enhanced backend/post-processing techniques to ultrasound images, as part of offloading ultrasound image processing from the portable ultrasound system  202 . Specifically, the external ultrasound docking unit  204  can apply backend processing to ultrasound images, e.g. those that are generated by either or both the portable ultrasound processing unit  212  and the external ultrasound docking unit  204  itself. Enhanced backend processing, can include applicable image processing techniques for preparing ultrasound images for display. For example, the external ultrasound docking unit  204  can perform, as part of backend processing, up sampling, down sampling, log compression, detection, spatial filtering, adaptive filtering, scan conversion, and the like, for displaying images. 
     The external ultrasound docking unit  204  can offload ultrasound image processing from the portable ultrasound system  202  when the portable ultrasound system  202  is electrically coupled to the external ultrasound docking unit  204 . Specifically, the external ultrasound docking unit  204  can offload ultrasound image processing from the portable ultrasound system  202  when the portable ultrasound system  202  is both physically and electrically coupled to the external ultrasound docking unit  204 . For example, the portable ultrasound system  202  can automatically offload processing to the external ultrasound docking unit  204  when the portable ultrasound system  202  is docked and electrically coupled to the external ultrasound docking unit  204 . Further, the portable ultrasound system  202  can automatically offload processing to the external ultrasound docking unit  204  when the portable ultrasound system  202  is electrically coupled to the external ultrasound docking unit  204  even though the portable ultrasound processing unit  212  has the computational power to perform the processing. For example, even if the portable ultrasound processing unit  212  has the processing power to perform 2D image processing, the portable ultrasound system  202  can still offload the 2D image processing to the external ultrasound docking unit  204 . For example, the portable ultrasound docking unit  204  may offload the 2D image processing to conserve battery power or reduce heat, as described in greater detail below. 
     In various embodiments, the external ultrasound docking unit  204  and the portable ultrasound processing unit  212  can be configured to perform ultrasound image processing in parallel to generate ultrasound images. Specifically, the external ultrasound docking unit  204  and the portable ultrasound processing unit  212  can perform ultrasound image processing in parallel to conserve computational resources at the external ultrasound docking unit  204  and the portable ultrasound processing unit  212 . For example, the portable ultrasound processing unit  212  can apply an applicable beamforming technique to channel domain data gathered by the portable ultrasound system  202  in order to generate beamformed data. The external ultrasound docking unit  204  can subsequently process the beamformed data generated by the portable ultrasound processing unit  212  to generate ultrasound images. Further, the portable ultrasound processing unit  212  can continue to generate additional beamformed data as the external ultrasound docking unit  204  processes the beamformed data already generated by the portable ultrasound system  202 . 
     As part of offloading processing from the portable ultrasound system  202  to the external ultrasound docking unit  204 , the portable ultrasound processing unit  212  can actually determine whether to offload ultrasound image processing to the external ultrasound docking unit  204 . Subsequently, the portable ultrasound processing unit  212  can offload the ultrasound image processing to the external ultrasound docking unit  204  if it determines to offload the processing. In offloading processing, and as discussed previously, the portable ultrasound processing unit  212  can send applicable data for offloading ultrasound image processing to the external ultrasound docking unit  204  if it is determined to offload the processing to the external ultrasound docking unit  204 . For example, if the portable ultrasound processing unit  212  determines to offload beamforming and subsequent image creation to the external ultrasound docking unit  204 , then the portable ultrasound processing unit  212  can send gathered channel domain data to the external ultrasound docking unit  204 . In another example, if the portable ultrasound processing unit  212  determines to offload image creation from beamformed data to the external ultrasound docking unit  204 , then the portable ultrasound processing unit  212  can send generated beamformed data to the external ultrasound docking unit  204 . In yet another example, if the portable ultrasound processing unit  212  determined to offload backend processing to the external ultrasound docking unit  204 , then the portable ultrasound processing unit  212  can send generated ultrasound images to the external ultrasound docking unit  204  for enhanced backend processing. 
     Alternatively, if the portable ultrasound processing unit  212  determines to not offload ultrasound image processing to the external ultrasound docking unit  204 , then the portable ultrasound processing unit  212  can perform the ultrasound image processing. For example, if the portable ultrasound processing unit  212  determines to refrain from offloading the image processing, then the portable ultrasound processing unit  212  can form beamformed data to generate one or more ultrasound images. Further, if the portable ultrasound processing unit  212  determines to refrain from offloading the image processing, then the portable ultrasound processing unit  212  can perform backend processing on ultrasound images generated by the portable ultrasound processing unit  212 . 
     The portable ultrasound processing unit  212  can determine whether to offload ultrasound image processing to the external ultrasound docking unit  204  based on characteristics of the ultrasound image processing. Characteristics of ultrasound image processing can include types of operations to perform in the ultrasound image processing, an amount of computational resources needed to perform the ultrasound image processing, and storage requirements needed to perform the ultrasound image processing. For example, if the portable ultrasound processing unit  212  determines that the ultrasound image processing incudes 3D image processing, then the portable ultrasound processing unit  212  can determine to offload the processing to the external ultrasound docking unit  204 . 
     Further, the portable ultrasound processing unit  212  can determine whether to offload ultrasound image processing to the external ultrasound docking unit  204  based on an amount of available processing power at the portable ultrasound processing unit  212 . Specifically, if the portable ultrasound processing unit  212  determines that it does not have enough processing power to provide specific ultrasound image processing, then the portable ultrasound processing unit  212  can determine to offload the processing to the external ultrasound docking unit  204 . Alternatively, if the portable ultrasound processing unit  212  determines that it does have enough processing power to provide specific ultrasound image processing, then the portable ultrasound processing unit  212  can perform the processing itself instead of offloading the processing. 
     Additionally, the portable ultrasound processing unit  212  can determine whether to offload ultrasound image processing to the external ultrasound docking unit  204  based on whether the portable ultrasound system  202  is electrically coupled to the external ultrasound docking unit  204 . Specifically, the portable ultrasound processing unit  212  can automatically offload all or a portion of ultrasound image processing to the external ultrasound docking unit  204  when the portable ultrasound system  202  is electrically coupled to the external ultrasound docking unit  204 . 
     In some embodiments, the portable ultrasound processing unit  212  (or the processor  214  or other component of the portable ultrasound system  202 ) may determine whether to offload ultrasound image processing to the external ultrasound docking unit  204  based on the heat level of the portable ultrasound processing unit  212  (or the processor  214 , the battery  216 , and/or other components of the portable ultrasound system  202 ). Heat degrades battery performance and may cause wear on electrical components. Accordingly, the temperature of the portable ultrasound processing unit  212  may be obtained via one or more temperature sensors  220 , such as a thermocouple, a resistance temperature detector (RTD), a thermistor, and/or semiconductor-based based temperature sensor included in an integrated circuit (IC) or the like. If the temperature exceeds a threshold or exceeds a threshold for a predetermined time period, the portable ultrasound processing unit  212  may determine to offload ultrasound image processing to the external ultrasound docking unit  204 . 
     Alternatively, or in addition, the portable ultrasound processing unit  212  may determine whether to offload ultrasound image processing to the external ultrasound docking unit  204  based on the current or projected battery level of the portable ultrasound processing unit  212 . For example, the portable ultrasound processing unit  212  may have sufficient processing power to perform a desired ultrasound operation, but the battery level sensor  218  may detect that the current battery level is insufficient to be able to complete the ultrasound operation or complete the ultrasound operation with a desired margin of error or cushion. In such a case, the portable ultrasound processing unit  212  may determine to offload ultrasound image processing to the external ultrasound docking unit  204 . 
     In other embodiments, the portable ultrasound processing unit  212  may determine whether to offload ultrasound image processing to the external ultrasound docking unit  204  based on a selected examination type (e.g., transesophageal echocardiography) or a particular examination area (e.g., heart). If a transesophageal echocardiography examination type (or other examination type requiring a particular amount of processing power, storage, battery capacity, etc.) is selected, the portable ultrasound processing unit  212  may offload ultrasound image processing to the external ultrasound docking unit  204 . By contrast, if a doppler examination of the heart is selected, the portable ultrasound processing unit  212  may decide to not offload ultrasound image processing to the external ultrasound docking unit  204  and perform the processing internally. 
     In some embodiments, the determination of whether to offload may be made with reference to prior user input. For example, the user may specify at a configuration stage, for example, that certain types of examinations should be offloaded (or not offloaded) or that certain battery capacities, storage capacities, thermal limits, or the like, should apply to the determination of whether to offload. 
     Alternatively, or in addition, the determination may be made using machine learning. For example, the portable ultrasound processing unit  212  may determine during a particular examination that an ultrasound operation cannot be completed in real-time within the portable ultrasound processing unit  212 . Likewise, the portable ultrasound processing unit  212  may determine during an examination that certain ultrasound operations will exceed the battery capacity of the portable ultrasound processing unit  212  or result in heat levels that exceed a certain threshold within the portable ultrasound processing unit  212 . Using a machine learning system  226  (e.g., neural network) accessible to the portable ultrasound processing unit  212 , the portable ultrasound processing unit  212  may learn whether offloading will be required and automatically offload (or prompt a user of the necessity of offloading) in subsequent operations where offloading may be needed. 
     Any combination of two or more of the foregoing determinations may be combined in deciding whether to offload processing. Furthermore, determining whether to offload may include balancing factors of processing power, heat, battery capacity, storage requirements, and the like, with user settings and/or processing goals specified by the user. 
     At the time the determination is made to offload the processing, offloading may commence immediately if the portable ultrasound system  202  is docketed (e.g., electrically) connected to the external ultrasound docking unit  204 . If the portable ultrasound system  202  is not currently electrically connected to the external ultrasound docking unit  204 , the portable processing unit  212  may notify the user via any combination of audible, visual, or haptic means (e.g., light, sound, vibration), indicating that the user should connect the portable processing unit  212  to the external ultrasound docking unit  204  immediately, after a scan is finished, or within a particular time interval. 
     After ultrasound image processing is offloaded to the external ultrasound docking unit  204  and is actually performed by the external ultrasound docking unit  204 , then the generated ultrasound images can be sent back to the portable ultrasound system  202 . Specifically, ultrasound images generated at the external ultrasound docking unit  204  can be sent back to the portable ultrasound system  202  for display at the portable ultrasound system  202  or for further image processing. More specifically, the portable ultrasound system  202  can include a display for displaying ultrasound images, e.g. ultrasound images processed, at least in part, by the external ultrasound docking unit  204 . For example, the external ultrasound docking unit  204  can perform enhanced backend processing on ultrasound images, and send the enhanced backend processed ultrasound images back to the portable ultrasound system  202  for display at the portable ultrasound system  202 . 
     The external ultrasound docking unit  204  can be configured to transfer power to the portable ultrasound system  202 . Specifically, the external ultrasound docking unit  204  can transfer power to the portable ultrasound system  202  through the docking connection  206 , when the portable ultrasound system  202  is electrically coupled to the external ultrasound docking unit  204 . Power transferred to the portable ultrasound system  202  by the external ultrasound docking unit  204  can be used to power the portable ultrasound system  202  during operation. For example, power transferred to the portable ultrasound system  202  by the external ultrasound docking unit  204  can be used to power the transmitter(s)  208  and the receiver(s) in transmitting and receiving ultrasound waves to and from a subject region. Further, power transferred to the portable ultrasound system  202  from the external ultrasound docking unit  204  can be used to recharge a power supply implemented as part of the portable ultrasound system  202 . Specifically, power transferred from the external ultrasound docking unit  204  to the portable ultrasound system  202  can recharge a battery integrated as part of the portable ultrasound system  202 . 
     The external ultrasound docking unit  204  can be implemented as part of an ultrasound cart. In being implemented in an ultrasound cart, the external ultrasound docking unit  204  can be movable as part of the cart. This is advantageous as the external ultrasound docking unit  204  can be moved to different examination rooms for performing different examinations. Further, the docking connection  206  can be implemented, at least in part, in an ultrasound cart. For example, the docking connection  206  can be formed by a communication bus implemented in an ultrasound cart. 
       FIG. 3  shows a block diagram of a distributed ultrasound system  300  with an expansion communication bus for enhanced image processing capabilities. This block diagram consists of two primary systems, a portable ultrasound system  301  and an external ultrasound docking unit  302 . The portable ultrasound system  301  can function according to an applicable portable ultrasound system for gathering channel domain data and generating one or more ultrasound images, such as the portable ultrasound system  202  shown in  FIG. 2 . The external ultrasound docking unit  302  functions according to an applicable ultrasound docking unit for offloading processing from a portable ultrasound system, such as the external ultrasound docking unit  204  shown in  FIG. 2 . 
     The portable ultrasound system  301  can be a fully functioning ultrasound system that can operate independently from the external ultrasound docking unit  302 . This portable ultrasound system  301  can have standard as well as non-standard capabilities to enable it to augment the overall performance of the system when connected to the external ultrasound docking unit  302 . Specifically, the portable ultrasound system  301  can offload image processing to the external ultrasound docking unit  302  to augment overall performance of the distributed ultrasound system  300 . 
     The portable ultrasound system  301  includes one or more transmitters  310  for transmitting ultrasound waves into a region under investigation. The signals from the transmitters  310  can be passed through a T/R switch  311  to a transducer port  312 . A transducer can be connected to the transducer port  312  where the signals can be transmitted and received from interactions with the region under investigation. Further, a transducer can be connected to a multi-transducer port  320  in the external ultrasound docking unit  302  to transmit and receive signals to and from a region under investigation. Received signals can pass through the transducer port  312  and the T/R switch  311  to the receiver  313 . The receiver  313  can amplify and digitize these signals. The receiver  313  can also amplify these signals at different values based on the depth of where the signals are received. The digitized signals from the receiver  313  can then be passed to the image formation module  314  where the ultrasound image is formed. 
     Once image formation is completed by the image formation module  314 , the data of the images can be transferred across a COMM BUS  315  to several different locations depending on the connectivity as well as what processing is required for the image data. Specifically, if the portable ultrasound system  301  is not coupled, e.g. electrically coupled, to the external ultrasound docking unit  302 , then the images can be backend processed by the backend processing module  316 . Specifically, the image data can be processed and formatted by the backend processing module  316  in a manner for viewing. As follows, after backend processing by the backend processing module  316 , the data can be transferred over the COMM BUS  315  to the CPU  317  and subsequently displayed on the display  318  for viewing at the portable ultrasound system  301 . 
     If the portable ultrasound system  301  is connected to the external ultrasound docking unit  302 , then the image data generated by the image formation module  314  can be transferred over the COMM BUS  315  to the expansion slots  330  of the external ultrasound docking unit  302 . The expansion slots  330  contain one or a combination of a GPU Processor  331 , a DSP Processor  332 , a CPU Processor  333 , and an FPGA Board  334 . These processors  331 - 334  can be configured to process the image data received from the COMM BUS  315 . 
     Once the data is done being processed by the expansion slots  330 , the data can be transferred back over the COMM BUS  315  to the backend processor  316 . Specifically, the data can be transferred to the backend processor  316  if additional processing or data formatting is needed. Alternatively, the data, after being processed by the expansion slots  330 , can be directly transferred to the CPU  317  for presentation on the display  318 . 
     Beyond just modules for performing the previously described image processing path, the portable ultrasound system  301  can also include a power supply  350  and a battery  351 . The power supply  350  can provide a regulated power supply to the portable ultrasound system  301 , including the above-mentioned modules for performing image processing both at the portable ultrasound system  301  and for offloading image processing from the portable ultrasound system  301 . The power supply  350  can receive power from one or a combination of the battery  351 , integrated as part of the portable ultrasound system  301 , a power supply  341  of the external ultrasound docking unit  302 , and an external power supply, e.g. a wall main power supply. Specifically, the external ultrasound docking unit  302  includes a power supply  341  that can provide power to the portable ultrasound system  301  when docked. The power supply  341  can provide all or a portion of regulated power to the sub systems within and connected to the external ultrasound docking unit  302 . For example, the expansion slots  330  and the processing boards within the expansion slots  330  can receive power from the power supply  341 . The power supply  341  can also provide power to the multi-transducer port  320 , e.g. to switch between active transducers. The power supply  341  can obtain power from either a battery  342 , integrated as part of the external ultrasound docking unit  302 , or from power input  340  that is connected to an external power supply, e.g. a main wall power supply. 
       FIG. 4  shows a block diagram of another distributed ultrasound system  400  with an expansion communication bus for enhanced image formation and image processing capabilities. This block diagram consists of two primary systems, a portable ultrasound system  401  and an external ultrasound docking unit  402 . The portable ultrasound system  401  can function according to an applicable portable ultrasound system for gathering channel domain data and generating one or more ultrasound images, such as the portable ultrasound system  202  shown in  FIG. 2 . The external ultrasound docking unit  402  functions according to an applicable ultrasound docking unit for offloading processing from a portable ultrasound system, such as the external ultrasound docking unit  204  shown in  FIG. 2 . 
     The portable ultrasound system  401  can be a fully functioning ultrasound system that can operate independently from the external ultrasound docking unit  402 . This portable ultrasound system  401  can have standard as well as non-standard capabilities to enable it to augment the overall performance of the system when connected to the external ultrasound docking unit  402 . Specifically, the portable ultrasound system  401  can offload image processing to the external ultrasound docking unit  402  to augment overall performance of the distributed ultrasound system  400 . 
     The portable ultrasound system  401  can include one or more transmitters  410  for transmitting ultrasound waves into a region of interest. The signals from the transmitters  410  can be passed through a T/R switch  411  to the transducer port  412 . A transducer can be connected to the transducer port  412  where the signals are transmitted and received from interactions with the region being investigated. Further, the transducer port  412  can be connected to a multi-transducer port  420 . The multi-transducer port  420  can be implemented as part of the external ultrasound docking unit  402  such that the transducer would then be connected to the multi-transducer port  420  to transmit and receive signals for interaction with a region being investigated. The received signals can pass through the transducer port  412  and the T/R switch  411  to the receiver  413 . 
     The receiver  413  can amplify and digitize the received signals. Specifically, the receiver  413  can amplify received signals at different values based on the depth of where the signals are received. The digitized signals from the receiver  413  can then be passed on to the COMM BUS  415 . The COMM BUS  415  can transfer the data to the image formation module  414  when the system  400  is operating in a portable format. Once the image is formed, the data can then be passed again to the COMM BUS  415  to the backend processing  416  module. The backend processing module  416  can process and format the image data in a manner suitable for viewing. The data can then be transferred across the COMM BUS  415  to the CPU  417  and to the display  418  for viewing. 
     Alternatively, if the portable ultrasound system  401  is docked in the external ultrasound docking unit  402 , then the image formation module  414  and the backend processing module  416  tasks can be augmented through the additional processing capabilities contained within the external ultrasound docking unit  402 , e.g. through the expansion slots  430 . The types of processors included in the expansion slots  430  can include one or an applicable combination of a GPU Processor  431 , a DSP Processor  432 , a CPU Processor  433 , and an FPGA Board  434 . 
     Beyond just modules for performing the previously described image processing path, the portable ultrasound system  401  can also include a power supply  450  and a battery  451 . The power supply  450  can provide a regulated power supply to the portable ultrasound system  401 , including the above-mentioned modules for performing image processing both at the portable ultrasound system  401  and for offloading image processing from the portable ultrasound system  401 . The power supply  450  can receive power from one or a combination of the battery  451 , integrated as part of the portable ultrasound system  401 , a power supply  441  of the external ultrasound docking unit  402 , and an external power supply, e.g. plugged into a wall main power supply. Specifically, the external ultrasound docking unit  402  includes a power supply  441  that can provide power to the portable ultrasound system  401  when docked. The power supply  441  can provide all regulated power to the sub systems within and connected to the external ultrasound docking unit  402 . For example, the expansion slots  430  and the processing boards within the expansion slots  431 - 434  can receive power from the power supply  441 . The power supply  441  can also provide power to the multi transducer port  420 , e.g. to switch between active transducers. The power supply  441  can obtain power from either a battery  442 , integrated as part of the external ultrasound docking unit  402 , or from power input  440  that is connected to an external power supply, e.g. a main power supply through a wall. 
       FIG. 5  shows a block diagram of a system  500  including a signal bus between a portable ultrasound system and expansion slots of an external docking unit, e.g. an ultrasound cart. The PCIe expansion slots  510  are a possible implementation given that PCIe is a current industry standard. Further, the PCIe expansion slots  510  are a possible implementation given that PCIe has sufficient data bandwidth to transfer information. 
     The PCIe expansion slots  510  can contain a number of PCIe compatible cards. Specifically, the slots  510  can contain expansion cards dedicated to enhance processing capabilities but would not be limited by any specific PCIe expansion slow, as any PCIe expansion compatible card could be connected. For example, there might be a desire, e.g. of research groups, to create a PCIe card to grab data directly from the PCIe bus. Example types of cards that can be contained in the PCIe expansion slots  510  include a GPU Processor  511 , a DSP processor  512 , a CPU processor  513 , and an FPGA board  514 . GPUs are extremely efficient in handling well-structured massively parallel applications. That is advantageous as a number of applications and processes in ultrasound are well aligned. Another possible card is a DSP processor(s)  512  as DSP processors tend to be very efficient in tasks that have sections that are well structured along with some degree of decision-based logic as well. Further, CPU processor(s)  513  can be used as CPU processors tend to be very efficient on decision-based logic tasks with a lower level of efficiency in massively parallel well-structured tasks. Another type of board that can be contained in the PCIe expansion slots  510  includes an FPGA board  514 . An FPGA board is good at handling massively parallel tasks in an energy efficient manner. However, FPGA boards require more time and effort to develop code for than the other processors. 
     The PCIe expansion slots  510  can have a physical connector  520  on the docking unit  502 . Specially, the connection  520  can be configured to mate with a portable ultrasound system PCIe connector  530  when the portable ultrasound system is docked on the cart/ultrasound docking unit. The portable ultrasound system can then utilize the resources of the expansion cards contained inside the PCIe expansion slots  510  through the PCIe bus  520 . 
       FIG. 6  is a flowchart  600  of an example method of providing a distributed ultrasound system configured to offload processing from a portable ultrasound system in the distributed ultrasound system. The example method shown in  FIG. 6 , can be implemented using an applicable distributed ultrasound system, such as the systems  200 ,  300 ,  400 , and  500  shown in  FIGS. 2-5 . 
     At step  602 , a portable ultrasound system is provided to a user. The portable ultrasound system can form part of a distributed ultrasound system. The portable ultrasound system can include a portable ultrasound processing unit configured to perform ultrasound image processing to generate ultrasound images. Further, the portable ultrasound system can include a transmitter(s) and a receiver(s) for transmitting and receiving ultrasound waves into and from a subject area in order to generate channel domain data. Subsequently, the portable ultrasound processing unit can apply ultrasound image processing to the channel domain data to generate the ultrasound images. 
     At step  604 , an external ultrasound docking unit is provided to the user. The external ultrasound docking unit can form the distributed ultrasound system with the portable ultrasound system. The external ultrasound docking unit can be configured to offload at least a portion of the ultrasound image processing from the portable ultrasound system in order to generate the ultrasound images. Specifically, the external ultrasound docking unit can offload the ultrasound image processing from the portable ultrasound system when the portable ultrasound system is electrically coupled, and potentially physically secured, to the external ultrasound docking unit. The external ultrasound docking unit can be implemented as part of an ultrasound cart. 
       FIG. 7  is a flowchart  700  of an example method of offloading processing from a portable ultrasound system in a distributed ultrasound system. The example method shown in  FIG. 7 , can be implemented using an applicable distributed ultrasound system, such as the systems  200 ,  300 ,  400 , and  500  shown in  FIGS. 2-5 . 
     At step  702 , a portable ultrasound system is coupled to an external ultrasound docking unit. The portable ultrasound system can be electrically coupled to the external ultrasound docking unit, and potentially physically coupled to the external ultrasound docking unit. For example, the portable ultrasound system can be coupled to the external ultrasound docking unit through a communication bus. The portable ultrasound system can be configured to perform ultrasound image processing for generating ultrasound images. Specifically, the portable ultrasound system can be configured to perform ultrasound image processing on channel domain data gathered by the portable ultrasound system in order to generate ultrasound images. 
     At step  704 , at least a portion of the ultrasound image processing is offloaded from the portable ultrasound system to the external ultrasound docking unit to generate the ultrasound images. Specifically, the ultrasound image processing can be offloaded to the external ultrasound docking unit through an electrical coupling between the portable ultrasound system and the external ultrasound docking unit. For example, channel domain data can be transferred from the portable ultrasound system to the external ultrasound docking unit as part of offloading processing to the external ultrasound docking unit. In another example, beamformed data can be transferred from the portable ultrasound system to the external ultrasound docking unit as part of offloading processing to the external ultrasound docking unit. In yet another example, ultrasound images can be transferred from the portable ultrasound system to the external ultrasound docking unit, where backend processing can further be applied to the ultrasound images. 
     This disclosure has been made with reference to various exemplary embodiments including the best mode. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope of the present disclosure. For example, various operational steps, as well as components for carrying out operational steps, may be implemented in alternate ways depending upon the particular application or in consideration of any number of cost functions associated with the operation of the system, e.g., one or more of the steps may be deleted, modified, or combined with other steps. 
     While the principles of this disclosure have been shown in various embodiments, many modifications of structure, arrangements, proportions, elements, materials, and components, which are particularly adapted for a specific environment and operating requirements, may be used without departing from the principles and scope of this disclosure. These and other changes or modifications are intended to be included within the scope of the present disclosure. 
     The foregoing specification has been described with reference to various embodiments. However, one of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the scope of the present disclosure. Accordingly, this disclosure is to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope thereof. Likewise, benefits, other advantages, and solutions to problems have been described above with regard to various embodiments. However, benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, a required, or an essential feature or element. As used herein, the terms “comprises,” “comprising,” and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, a method, an article, or an apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, system, article, or apparatus. Also, as used herein, the terms “coupled,” “coupling,” and any other variation thereof are intended to cover a physical connection, an electrical connection, a magnetic connection, an optical connection, a communicative connection, a functional connection, and/or any other connection. 
     Those having skill in the art will appreciate that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.