Patent Description:
Ultrasound imaging systems are widely used for medical imaging. For example, a medical ultrasound system may include an ultrasound transducer probe coupled to a processing system and one or more display devices. The ultrasound transducer probe may include an array of ultrasound transducer elements that transmit acoustic waves into a patient's body and record acoustic waves reflected from the internal anatomical structures within the patient's body, which may include tissues, blood vessels, and internal organs. The transmission of the acoustic waves and/or the reception of reflected acoustic waves or echo responses can be performed by the same set of ultrasound transducer elements or different sets of ultrasound transducer elements. The processing system can apply beamforming, signal processing, and/or imaging processing to the received echo responses to create an image of the patient's internal anatomical structures.

Ultrasound imaging is a safe, useful, and in some applications, non-invasive tool for diagnostic examination, interventions, and/or treatment. Ultrasound imaging can provide insights into an anatomy before a surgery or other major procedure is performed as well as monitor and/or track changes to a particular anatomical feature over time. Many ultrasound imaging systems capture and/or calculate dimensions of anatomical structures during an ultrasound examination.

Ultrasound imaging systems may be modelled as the convolution of a spatially varying point spread function having a Gaussian blurring effect which increases with depth or distance from the ultrasound transducer probe. The blurring effect of the ultrasound point spread function may result in significant inaccuracies when calculating dimensions of anatomical structures within a patient. For example, ultrasound imaging systems tend to underestimate volumes and other dimensions of hypoechoic chambers such as ventricles, atria, or cysts and overestimate hyperechoic regions. Efforts to address these inaccuracies, such as with deconvolution are unsatisfactory. For example, deconvolution of ultrasound imaging is generally difficult and impractical for timely quantification. Other ultrasound imaging systems may apply a constant offset to calculated boundaries to mitigate the inaccuracies introduced by the point spread function, but the spatially varying nature of the point spread function blurring effect makes such a solution crude and inaccurate.

In <CIT>, it is disclosed a method for determining a contour of an organ in an ultrasound image that includes detecting an organ within the ultrasound image, obtaining a centroid position for the organ, extending a set of radial lines from the centroid position beyond an expected organ boundary, determining cost values at candidate nodes on each radial line, of the set of radial lines, by applying costs along gradient vectors that are normal to a contour between adjacent nodes on different radial lines, and selecting a final organ boundary contour based on a cost function analysis of paths through the candidate nodes.

Embodiments of the present disclosure are systems, devices, and methods for ultrasound imaging that provide more accurate representation of anatomy in ultrasound images by correcting inaccuracies resulting from the ultrasound point spread function. For example, the present disclosure includes calculating and applying a correction vector to boundaries of anatomical structures imaged in a patient's anatomy.

The ultrasound imaging system described herein may receive and/or calibrate a constant value corresponding to characteristics of an anatomical structure to be imaged. These characteristics may include acoustic impedance of materials in or around the anatomical structure. The system may image the anatomical structure and use the received and/or calibrated value to calculate a vector corresponding to the direction and distance between a measured boundary of the anatomical structure and the actual boundary of the anatomical structure. This correction vector may vary depending on the orientation or skew angle of a boundary of an anatomical structure with respect to the ultrasound imaging beam and the magnitude of the ultrasound point spread function blurring effect varying with depth at the location. The ultrasound imaging system may then apply the appropriate correction vector to any location along a boundary of an anatomical structure to correct for any inaccuracies in volume or other dimension of the anatomical structure.

The constant value received and/or calibrated by the ultrasound imaging system may be calibrated before an imaging procedure is performed. An ultrasound phantom of a known volume having similar characteristics including acoustic impedance, volume, overall shape, or other characteristics, may be used to calibrate the constant. Least squares fitting may be used by the ultrasound imaging system to determine the most accurate value of the constant to be applied for anatomical structures similar to the phantom used. Other forms of regression analysis may similarly be employed.

The ultrasound imaging system may display to a user metrics related to the dimensions of the anatomical structure being imaged. These metrics may include measurements made before and after a correction vector is applied to an image. The ultrasound imaging system may further display to a user one or more ultrasound images or videos. Displayed ultrasound images or videos may comprise lines or other graphical representations generated and overlaid on the image or video representing boundaries of an anatomical structure as calculated by the ultrasound imaging system.

In an exemplary aspect, an ultrasound imaging system comprises a processor circuit configured for communication with an ultrasound probe, the processor circuit configured to: receive, from the ultrasound probe, ultrasound data representative of an ultrasound beam imaging an anatomical structure; determine, based on the ultrasound data, a measured boundary of the anatomical structure, wherein the measured boundary includes a plurality of locations; determine a plurality of correction vectors corresponding to the plurality of locations of the measured boundary, wherein a magnitude of a respective correction vector is based on at least one of: a depth of a corresponding location relative to the ultrasound probe; or an orientation of the measured boundary at the corresponding location relative to the ultrasound beam; apply the plurality of correction vectors to the plurality of locations of the measured boundary to determine a corrected boundary; and output, to a display in communication with the processor circuit, an ultrasound image based on the ultrasound data, wherein the ultrasound image includes the corrected boundary.

In some aspects, a direction of the plurality of correction vectors is at least one of normal to the measured boundary or normal to the corrected boundary. The plurality of correction vectors are configured to correct an effect of a point spread function of the ultrasound imaging system. In some aspects, the processor circuit is configured to model the point spread function as a Gaussian function. In some aspects, the magnitude of the respective correction vector is based on the depth of the corresponding location relative to the ultrasound probe and the orientation of the measured boundary at the corresponding location relative to the ultrasound beam. In some aspects, the magnitude of the respective correction vector, for a given orientation of the measured boundary at the corresponding location, is larger when the corresponding location is at a larger depth relative to the ultrasound probe and smaller when the corresponding location is at a smaller depth relative to the ultrasound probe. In some aspects, the magnitude of the respective correction vector, for a given depth of the corresponding location relative to the ultrasound probe, is larger when the orientation of the measured boundary is parallel to the ultrasound beam and smaller when the orientation of the measured boundary is perpendicular to the ultrasound beam. In some aspects, the plurality of correction vectors is further based on a calibrated value corresponding to one or more characteristics of the anatomical structure. In some aspects, the processor circuit is further configured to calculate, based on the corrected boundary, a metric associated with the anatomical structure. In some aspects, the processor circuit is configured to output the calculated metric to the display. In some aspects, the metric comprises a volume of the anatomical structure. In some aspects, the processor circuit is further configured to output the measured boundary to the display. In some aspects, the corrected boundary comprises a graphical overlay on the ultrasound image. In some aspects, a direction of the plurality of correction vectors is: inward relative to the measured boundary when the anatomical structure comprises a hyperechoic chamber; and outward relative to the measured boundary when the anatomical structure comprises a hypoechoic chamber. In some aspects, the system further comprises the ultrasound probe.

In an exemplary aspect, an ultrasound imaging method comprises receiving, at a processor circuit in communication with an ultrasound probe, ultrasound data representative of an ultrasound beam imaging an anatomical structure; determining, by the processor circuit, a measured boundary of the anatomical structure based on the ultrasound data, wherein the measured boundary includes a plurality of locations; determining, by the processor circuit, a plurality of correction vectors corresponding to the plurality of locations of the measured boundary wherein the plurality of correction vectors are configured to correct an effect of a point spread function of the ultrasound imaging system, wherein a magnitude of a respective correction vector is based on at least one of: a depth of a corresponding location relative to the ultrasound probe; or an orientation of the measured boundary at the corresponding location relative to the ultrasound beam; applying, by the processor circuit, the plurality of correction vectors to the plurality of locations of the measured boundary to determine a corrected boundary; and outputting, to a display in communication with the processor circuit, an ultrasound image based on the ultrasound data, wherein the ultrasound image includes the corrected boundary.

For example, while the focusing system is described in terms of cardiovascular imaging, it is understood that it is not intended to be limited to this application. The system is equally well suited to any application requiring imaging within a confined cavity.

<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 an 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>. The probe <NUM> may include a transducer array <NUM>, a beamformer <NUM>, a processor circuit <NUM>, and a communication interface <NUM>. The host <NUM> may include a display <NUM>, a processor circuit <NUM>, and a communication interface <NUM>.

Probe <NUM> may be in any suitable form for any suitable ultrasound imaging application including both external and internal ultrasound imaging. In some embodiments, the probe <NUM> is an external ultrasound imaging device including a housing configured for handheld operation by a user. The transducer array <NUM> can be configured to obtain ultrasound data while the user grasps the housing of the probe <NUM> such that the transducer array <NUM> is positioned adjacent to and/or in contact with a patient's skin. The probe <NUM> is configured to obtain ultrasound data of anatomy within the patient's body while the probe <NUM> is positioned outside of the patient's body. In some embodiment, the probe <NUM> can be an external ultrasound probe, such as a transthoracic echocardiography (TTE) probe.

In other embodiments, the probe <NUM> can be an internal ultrasound imaging device and may comprise a housing configured to be positioned within a lumen of a patient's body, including the patient's esophagus, heart chamber, coronary vasculature, peripheral vasculature, or other body lumen. In some embodiments, the probe <NUM> may be an intravascular ultrasound (IVUS) imaging catheter, or an intracardiac echocardiography (ICE) catheter. In other embodiments, probe <NUM> may be a transesophageal echocardiography (TEE) probe.

The transducer array <NUM> emits ultrasound signals towards an anatomical object <NUM> of a patient and receives echo signals reflected from the object <NUM> back to the transducer array <NUM>. The ultrasound transducer array <NUM> can include any suitable number of acoustic elements, including one or more acoustic elements and/or a plurality of acoustic elements. In some instances, the transducer array <NUM> includes a single acoustic element. In some instances, the transducer array <NUM> may include an array of acoustic elements with any number of acoustic elements in any suitable configuration. For example, the transducer array <NUM> can include between <NUM> acoustic element and <NUM> acoustic elements, including values such as <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, and/or other values both larger and smaller. In some instances, the transducer array <NUM> may include an array of acoustic elements with any number of acoustic elements in any suitable configuration, such as a linear array, a planar array, a curved array, a curvilinear array, a circumferential array, an annular array, a phased array, a matrix array, a one-dimensional (1D) array, a <NUM>. x dimensional array (e.g., a <NUM>. 5D array), or a two-dimensional (2D) array. The array of acoustic elements (e.g., one or more rows, one or more columns, and/or one or more orientations) can be uniformly or independently controlled and activated. The transducer array <NUM> can be configured to obtain one-dimensional, two-dimensional, and/or three-dimensional images of a patient's anatomy. In some embodiments, the transducer array <NUM> may include a piezoelectric micromachined ultrasound transducer (PMUT), capacitive micromachined ultrasonic transducer (CMUT), single crystal, lead zirconate titanate (PZT), PZT composite, other suitable transducer types, and/or combinations thereof.

The object <NUM> may include any anatomy, such as blood vessels, nerve fibers, airways, mitral leaflets, cardiac structure, abdominal tissue structure, appendix, large intestine (or colon), small intestine, kidney, liver, and/or any other anatomy of a patient. In some aspects, the object <NUM> may include at least a portion of a patient's large intestine, small intestine, cecum pouch, appendix, terminal ileum, liver, epigastrium, and/or psoas muscle. The present disclosure can be implemented in the context of any number of anatomical locations and tissue types, including without limitation, organs including the liver, heart, kidneys, gall bladder, pancreas, lungs; ducts; intestines; nervous system structures including the brain, dural sac, spinal cord and peripheral nerves; the urinary tract; as well as valves within the blood vessels, blood, chambers or other parts of the heart, abdominal organs, and/or other systems of the body. In some embodiments, the object <NUM> may include malignancies such as tumors, cysts, lesions, hemorrhages, or blood pools within any part of human anatomy. The anatomy may be a blood vessel, such as an artery or a vein of a patient's vascular system, including cardiac vasculature, peripheral vasculature, neural vasculature, renal vasculature, and/or any other suitable lumen inside the body. The anatomical object <NUM> may additionally include ventricles or atria. In addition to natural structures, the present disclosure can be implemented in the context of man-made structures such as, but without limitation, heart valves, stents, shunts, filters, implants and other devices.

The beamformer <NUM> is coupled to the transducer array <NUM>. The beamformer <NUM> controls the transducer array <NUM>, for example, for transmission of the ultrasound signals and reception of the ultrasound echo signals. In some embodiments, beamformer <NUM> may apply a time-delay to signals sent to individual acoustic transducers within an array in transducer <NUM> such that an acoustic signal is steered in any suitable direction propagating away from probe <NUM>. The beamformer <NUM> may further provide image signals to the processor circuit <NUM> based on the response of the received ultrasound echo signals. The beamformer <NUM> may include multiple stages of beamforming. The beamforming can reduce the number of signal lines for coupling to the processor circuit <NUM>. In some embodiments, the transducer array <NUM> in combination with the beamformer <NUM> may be referred to as an ultrasound imaging component.

The processor circuit <NUM> is coupled to the beamformer <NUM>. The processor circuit <NUM> may also be described as a processor circuit or processor. Processor circuit <NUM> may include a central processing unit (CPU), a graphical processing unit (GPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor circuit <NUM> may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The processor circuit <NUM> is configured to process the beamformed image signals. For example, the processor circuit <NUM> may perform filtering and/or quadrature demodulation to condition the image signals. The processor circuit <NUM> and/or <NUM> can be configured to control the array <NUM> to obtain ultrasound data associated with the object <NUM>.

The communication interface <NUM> is coupled to the processor circuit <NUM>. The communication interface <NUM> may include one or more transmitters, one or more receivers, one or more transceivers, and/or circuitry for transmitting and/or receiving communication signals. The communication interface <NUM> can include hardware components and/or software components implementing a particular communication protocol suitable for transporting signals over the communication link <NUM> to the host <NUM>. The communication interface <NUM> can be referred to as a communication device or a communication interface module.

The communication link <NUM> may be any suitable communication link. For example, the communication link <NUM> may be a wired link, such as a universal serial bus (USB) link or an Ethernet link. Alternatively, the communication link <NUM> nay be a wireless link, such as an ultra-wideband (UWB) link, an Institute of Electrical and Electronics Engineers (IEEE) <NUM> WiFi link, or a Bluetooth link.

At the host <NUM>, the communication interface <NUM> may receive the image signals. The communication interface <NUM> may be substantially similar to the communication interface <NUM>. The host <NUM> may be any suitable computing and display device, such as a workstation, a personal computer (PC), a laptop, a tablet, or a mobile phone.

The processor circuit <NUM> is coupled to the communication interface <NUM>. The processor circuit <NUM> may be implemented as a combination of software components and hardware components. The processor circuit <NUM> may include a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor circuit <NUM> may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The processor circuit <NUM> can be configured to generate image data from the image signals received from the probe <NUM>. The processor circuit <NUM> can apply advanced signal processing and/or image processing techniques to the image signals. In some embodiments, the processor circuit <NUM> can form three-dimensional (3D) volume image from the image data. In some embodiments, the processor circuit <NUM> can perform real-time processing on the image data to provide a streaming video of ultrasound images of the object <NUM>. In some aspects, the processor circuit <NUM> may further perform various calculations relating to a region of interest within the patient's body. These calculations may then be displayed to the sonographer or other user via display <NUM>.

The display <NUM> is coupled to the processor circuit <NUM>. The display <NUM> may be a monitor or any suitable display. The display <NUM> is configured to display the ultrasound images, image videos, and/or any imaging information of the object <NUM>.

The host <NUM> may include a memory <NUM>, which may be any suitable storage device, such as a cache memory (e.g., a cache memory of the processor circuit <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, solid state drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. The memory <NUM> can be configured to store patient files relating to a patient's medical history, history of procedures performed, anatomical or biological features, characteristics, or medical conditions associated with a patient, computer readable instructions, such as code, software, or other application, as well as any other suitable information or data.

<FIG> is a schematic diagram of a processor circuit <NUM>, according to embodiments of the present disclosure. The processor circuit <NUM> may be implemented in probe <NUM> and/or host <NUM> of <FIG>. One or more processor circuits <NUM> are configured to carry out various operations described herein. 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 <NUM>. 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 diagrammatic view of an anatomical boundary <NUM> within a region <NUM> defined by at least two media within a patient, according to aspects of the present disclosure. Although <FIG> depicts a two-dimensional cross-section of the boundary <NUM>, it is understood that the boundary <NUM> is a three-dimensional boundary within the patient. The boundary <NUM> and the cross-section of the boundary <NUM> can be any suitable shape. The three-dimensional boundary depicted in <FIG> may be of any suitable shape. The two-dimensional cross-section of the three-dimensional boundary may additionally be of any suitable shape.

A medium <NUM> forming the boundary <NUM> may be any suitable solid or semi-solid two- or three-dimensional structure, any liquid medium, or gas medium, and may be of any suitable material. For example, the medium <NUM> may include material of or relating to the structure of an organ, muscle, and/or other tissue in a patient's anatomy. The medium <NUM> may additionally include material that is substantially liquid in nature. For example, the medium <NUM> may include blood, blood plasma, interstitial fluid, lymph plasma, cerebrospinal fluid, intraocular fluid, serous fluid, synovial fluid, digestive fluid, urinary fluid, amniotic fluid, or any other type of suitable fluid. The medium <NUM> may additionally include any suitable gases found within a patient's anatomy, such as in the lungs, digestive tract, or any other location. In some embodiments, the medium <NUM> may include myocardium of the heart that defines a chamber within the heart. A medium <NUM> is also depicted in <FIG>. The medium <NUM> may also include any suitable anatomical structure, liquid, or gas within a patient and may include any of the aforementioned organs, muscles, tissues, liquids, and/or gases. In some embodiments, the medium <NUM> may be blood within a chamber of a heart. Accordingly, an exemplary embodiment the region <NUM> is an interface of the heart between the myocardium and the blood inside of the heart chamber. The medium <NUM> and the medium <NUM> may exhibit different acoustic impedances such that the boundary <NUM> may be detected and measured by the ultrasound imaging system <NUM>.

The boundary <NUM> may be defined by a surface <NUM> of medium <NUM> and/or a surface <NUM> of medium <NUM>. In some embodiments, the surface <NUM> of medium <NUM> and/or the surface <NUM> of medium <NUM> may be substantially uniform. For example, surface <NUM> of medium <NUM> may be substantially continuous at a region <NUM> such that there are no substantially pronounced protrusions or indentations along the surface <NUM> of medium <NUM>.

Region <NUM> may be imaged by ultrasound imaging system <NUM>. An ultrasound imaging beam <NUM>, depicted as downward arrows in <FIG>, may comprise acoustic waves emitted by transducers <NUM> of probe <NUM> as described previously with reference to <FIG>. In the embodiment of <FIG>, ultrasound imaging beam <NUM> may propagate in a direction from the top of region <NUM> to the bottom of region <NUM>. In general, it is understood that an ultrasound imaging beam may propagate in any suitable three-dimensional direction with respect to region <NUM> or any anatomical structure.

A plurality of indicators <NUM> are also depicted in <FIG>. In some embodiments, indicators <NUM> may represent the locations at which scatterers reflect from surface <NUM> of medium <NUM> and/or surface <NUM> of medium <NUM> and may define the location of the boundary <NUM> within region <NUM>. In some embodiments, the boundary <NUM> and/or indicators <NUM> are not displayed to a user in an ultrasound image on display <NUM> (<FIG>). In some embodiments, a graphical representation of the boundary <NUM> and/or any suitable number of indicators <NUM> may be generated and displayed by ultrasound imaging system <NUM> to a user via display <NUM>.

<FIG> is a diagrammatic view of an anatomical boundary <NUM> within a patient as measured by the ultrasound imaging system <NUM>, according to aspects of the present disclosure. <FIG> depicts a plurality of modified indicators <NUM> that represent scatterers associated with the ultrasound imaging beam <NUM> emitted by probe <NUM> and/or echoes reflected from surface <NUM> of medium <NUM> and/or surface <NUM> of medium <NUM> and subsequently detected by probe <NUM>. <FIG> additionally depicts a plurality of arrows also depicted in <FIG> representing the direction of the ultrasound imaging beam <NUM> emitted by probe <NUM>.

Ultrasound imaging system <NUM> may create an ultrasound image for display to a user via display <NUM> (<FIG>) via any suitable method. In some embodiments, ultrasound imaging system <NUM> may convolve a scatterer map created from acoustic signals reflected off various anatomical objects <NUM> received via transducers <NUM> within probe <NUM> with a multiplicative point spread function. In such embodiments, an ultrasound image created by ultrasound imaging system <NUM> may appear to be wider or stretched out as compared to the actual anatomical object <NUM> being imaged. Modified indicators <NUM> depict this widening effect in the form of a substantially oval shape, compared to the circular shape of the indicators <NUM> in <FIG>. For example, modified indicators <NUM> may correspond to indicators <NUM> of <FIG>, such that the location of the scatterers represented by indicators <NUM> are stretched by ultrasound imaging system <NUM> so as to be disfigured by some horizontal distance corresponding to the shape of modified indicators <NUM>. It is noted, that the widening effect illustrated in <FIG> occurs only in a direction orthogonal to the direction of imaging beam <NUM> and in every direction orthogonal to imaging beam <NUM>. For example, as previously mentioned, although modified indicators <NUM> are depicted in two dimensions or in a lateral dimension from a center point of modified indicators <NUM>, a similar effect of equal magnitude may be observed in an elevational direction from a center point of modified indicators <NUM> (e.g., into and out of the plane of the page), such that the aforementioned scatterers are depicted as spread in every direction orthogonal to the direction of imaging beam <NUM> extending both horizontally to the left and right in both directions as shown two dimensionally as well as three dimensionally.

At least one of the consequences of the aforementioned stretching effect produced by convolving a received scatterer map with a point spread function is the boundary <NUM> between medium <NUM> and medium <NUM> also appears to be displaced by a corresponding distance orthogonal to the direction of imaging beam <NUM> within an ultrasound image generated by ultrasound imaging system <NUM>. <FIG>, therefore, depicts an additional boundary line corresponding to measured boundary <NUM> separating medium <NUM> and medium <NUM>. Measured boundary <NUM> does not depict the accurate location of the actual boundary <NUM> between medium <NUM> and medium <NUM>. Such a discrepancy may result in erroneous calculations of anatomical areas and/or volumes, and subsequently flow rates, efficiencies, and any number of other metrics measured or calculated based on measurements from ultrasound imaging system <NUM>.

Curve <NUM> is also depicted in <FIG> representing the Gaussian nature of the distribution of scatterers within a convolved scatterer map used to create an ultrasound image frame. The Gaussian spread depicted by curve <NUM> may substantially correlate to the extent or magnitude of stretching shown by modified indicators <NUM> that occurs during an imaging process.

Also depicted in <FIG> is a measured surface <NUM> of medium <NUM> as measured by ultrasound imaging system <NUM>. The location of measured surface <NUM> is not the same as the location of actual surface <NUM> of medium <NUM> in <FIG> due to the spreading effect mentioned previously. Additionally, measured surface <NUM> of medium <NUM> is depicted in <FIG>. Similarly, the location of measured surface <NUM> is not the same as the location of the actual surface <NUM> of medium <NUM> in <FIG>.

<FIG> is a schematic diagram of the anatomical region <NUM> within the patient as measured by the ultrasound imaging system <NUM>, illustrating the difference between the actual boundary <NUM> and the measured boundary <NUM>, according to aspects of the present disclosure. As previously mentioned, due to the spreading effect inherent in ultrasound imaging via convolving scatterer maps with point spread functions, each element of an ultrasound image may be displaced at some distance orthogonal to the direction of an ultrasound imaging beam <NUM>. In <FIG>, the measured boundary <NUM> is depicted displaced at a distance corresponding to the magnitude of vector <NUM> from actual boundary <NUM>. While the direction of vector <NUM> will be in a direction orthogonal to the direction of ultrasound imaging beam <NUM>, the particular direction of the vector <NUM> to the right in <FIG> is exemplary. It is understood that the vector <NUM> may extend in any direction orthogonal to ultrasound imaging beam <NUM>, including to the left (opposite to the direction of vector <NUM> in <FIG>), into the page, or out of the page.

The magnitude of vector <NUM> may be dependent on a calibrated value corresponding to the characteristics of medium <NUM> (<FIG>) and medium <NUM> (<FIG>) as will be discussed in more detail hereafter and in reference to <FIG>, and <FIG>. However, the magnitude of vector <NUM> may be approximated to vary with distance from probe <NUM> linearly. In other embodiments, other relationships between the magnitude of vector <NUM> and distance from probe <NUM> may additionally be used to approximate the appropriate magnitude of vector <NUM> at various locations from probe <NUM> within a patient's anatomy.

Displacement vector <NUM> represents a distance between actual boundary <NUM> and measured boundary <NUM> in a direction normal to the surface <NUM> of medium <NUM> and/or the surface <NUM> or medium <NUM> (<FIG>). Displacement vector <NUM> need not be oriented orthogonal to the direction of ultrasound imaging beam <NUM> like vector <NUM> as the direction of displacement vector <NUM> is dictated by the orthogonal, or in other words, perpendicular, or normal, direction of surface <NUM> of medium <NUM> and/or surface <NUM> of medium <NUM>. The magnitude of displacement vector <NUM> may represent the extent to which the spreading effect caused by convolving a scatterer map with a point spread function applies in a direction normal to the boundary <NUM> and represents an approximation of the distance the measured boundary <NUM> varies from the actual boundary <NUM>. Displacement vector <NUM> may be calculated as (N · D)N, wherein D represents vector <NUM> and N represents a surface normal vector of boundary <NUM>.

In <FIG>, measured boundary <NUM> is depicted to the right of actual boundary <NUM> such that measured boundary <NUM> appears to a user of ultrasound imaging system <NUM> to be farther away from probe <NUM> than actual boundary <NUM>. However, in other embodiments, measured boundary <NUM> may be depicted to the left of actual boundary <NUM>, such that measured boundary <NUM> appears to a user of ultrasound imaging system <NUM> to be closer to the probe <NUM> than actual boundary <NUM>. The location of measured boundary <NUM> depends primarily on the echogenicity or other characteristics of the anatomical object measured, such as the acoustic impedance, of medium <NUM> and medium <NUM> (<FIG> and <FIG>). When the boundary <NUM> is between muscle and blood, the measured boundary <NUM> may be offset in the direction of the blood. Ultrasound imaging system <NUM> may successfully calculate vector <NUM> and/or displacement vector <NUM> in either of the aforementioned situations, including where measured boundary <NUM> is measured as being closer to probe <NUM> than actual boundary <NUM> or vice versa.

<FIG> is a diagrammatic view of the anatomical region <NUM> within the patient as measured by the ultrasound imaging system <NUM>, illustrating a correction of the difference between the actual boundary <NUM> and the measured boundary <NUM>, according to aspects of the present disclosure. <FIG> depicts correction vector <NUM>, which represents the distance and direction from a point <NUM> on the measured boundary <NUM> to a point <NUM> on actual boundary <NUM>. The correction vector <NUM> is normal to measured boundary <NUM> and/or the actual boundary <NUM>. The correction vector <NUM> may be approximated as a vector of equal magnitude but opposite direction to displacement vector <NUM> (<FIG>). For example, correction vector <NUM> may be approximated as - (N · D)N , N(-D · N), or any equivalent variation, where D represents vector <NUM> and N represents a surface normal vector of boundary <NUM>. Point <NUM> may be any suitable position or location on surface <NUM> of medium <NUM> and/or surface <NUM> of medium <NUM>. In addition, point <NUM> may be any corresponding point such that the correction vector <NUM> is normal to boundary <NUM> and/or boundary <NUM> approximately at or along surface <NUM> of medium <NUM> and/or surface <NUM> of medium <NUM>. It is noted that the correction vector <NUM>, in many cases, is only an approximation of the magnitude and direction of displacement between the measured boundary <NUM> and the actual boundary <NUM>. This approximation is based on the assumption that the vectors <NUM> and <NUM> are substantially the same at the points <NUM> and <NUM>. At the scales of the magnitude of the vector <NUM>, this requirement is met. In addition, the chamber surfaces at boundary <NUM> are in most cases comparatively flat on the order of the point spread function effect. It is additionally noted that although only one correction vector <NUM> is depicted in <FIG> between point <NUM> and point <NUM>, any suitable number of correction vectors <NUM> may be calculated or approximated by the ultrasound imaging system <NUM> at any point along a boundary of the anatomical structure to be measured.

<FIG> is a diagrammatic view of an anatomical structure <NUM> within a patient as measured by the ultrasound imaging system <NUM>, illustrating the difference in location between an actual boundary <NUM> and a measured boundary <NUM>, according to aspects of the present disclosure. Anatomical structure <NUM> may be any suitable organ, muscle, tissue, and/or natural/man-made structure within a patient's anatomy. In an exemplary embodiment, anatomical structure <NUM> is a ventricle within a heart. As illustrated in <FIG>, anatomical structure <NUM> may be imaged by the ultrasound imaging system <NUM> which emits an imaging beam <NUM>, the direction of which is indicated with corresponding arrows. As previously mentioned, the spreading effect resulting from convolving a scatterer map with a point spread function increases with depth, or distance from the ultrasound probe. To illustrate the effect, a plurality of Gaussian curves is depicted adjacent to anatomical structure <NUM>. The Gaussian curves <NUM>, <NUM>, and <NUM> illustrate the lateral component of the ultrasound point spread function as it is modelled across the acquisition space as PSF(x) as a Gaussian curve with a σ varying across space. Gaussian curve <NUM> positioned in closest proximity to the source of the imaging beam <NUM> (e.g., the ultrasound probe <NUM> of <FIG>) illustrates a less significant spreading effect than either Gaussian curve <NUM> or Gaussian curve <NUM>. Gaussian curve <NUM>, which is positioned at a distance farther away from the probe than Gaussian curve <NUM> and closer to probe than Gaussian curve <NUM>, illustrates a spreading effect greater than Gaussian curve <NUM> and less than Gaussian curve <NUM>. Subsequently, Gaussian curve <NUM> positioned at a point furthest away from probe illustrates a more significant spreading effect than either Gaussian curve <NUM> or Gaussian curve <NUM>. This point spread effect is only observed in a lateral direction (left/right in <FIG>) or an orthogonal direction (into and out of the page in <FIG>) to the direction of the imaging beam <NUM>. Stated differently, the Gaussian curve corresponding to the point spread function is of greater magnitude at points farther from the ultrasound probe <NUM>. For example, the magnitude of the Gaussian function, and subsequently the correction vector, for a given orientation of the measured boundary relative to the ultrasound probe is larger when the location is at a larger depth from the ultrasound probe and smaller when the location is at a smaller depth from the ultrasound probe.

Gaussian curve <NUM>, Gaussian curve <NUM>, and Gaussian curve <NUM> and their position with respect to the schematic diagram of anatomical structure <NUM> in <FIG> together illustrate the depth dependent nature of the point spread function observed in some embodiments of the present disclosure. In some embodiments, the point spread function may be modelled as a function, PSF(x). Variable x may be defined as a distance of a point within or around anatomical structure <NUM> from the source of the ultrasound beam <NUM> (the ultrasound probe <NUM>). PSF(x) and/or x may include or account for any suitable offset, constant, or additional function associated with the ultrasound probe <NUM>, anatomical structure <NUM>, patient anatomy, and/or any other feature or characteristic of a particular application of the present disclosure. As shown by Gaussian curve <NUM>, Gaussian curve <NUM>, and Gaussian curve <NUM>, the effect of PSF(x) is to substantially to widen the Gaussian curve associated with x as x increases. The Gaussian curve modelled as PSF(x) quantifies only the lateral and/or orthogonal component of the ultrasound point spread function.

Two boundary lines are also depicted in <FIG>: actual boundary <NUM> and measured boundary <NUM>. Actual boundary <NUM> may be substantially similar to actual boundary <NUM> depicted in previously presented figures. In addition, measured boundary <NUM> may be substantially similar to measured boundary <NUM> also depicted in previously presented figures. Due to the ultrasound point spread function, a measured boundary in a hypoechoic chamber similar to anatomical structure <NUM> (e.g., ventricles, atria, cysts, and/or other chambers with echogenic exteriors) is blurred to appear farther into the chamber than it really is in the anatomy of the patient. In other words, the ultrasound imaging system <NUM> may tend to underestimate volume measurements of hypoechoic chambers. When hyperechoic regions are measured by ultrasound imaging system <NUM>, the opposite effect is observed. Stated differently, for hypoechoic chambers, like the one shown in <FIG>, the displacement vectors extend from the actual boundary <NUM> inward to the measured boundary <NUM> and the correction vectors <NUM> shown in <FIG> extend in an opposite outward direction from the measured boundary <NUM> outward to the actual boundary <NUM>. By contrast, for hyperechoic chambers the opposite is true. The displacement vectors would extend from the actual boundary outward to the measured boundary and the correction vectors would extend in an inward direction from the measured boundary back to the actual boundary.

Additionally, illustrated in <FIG> are a plurality of vectors <NUM>. Vectors <NUM> may be substantially similar to vector <NUM> (<FIG>) in that vectors <NUM> represent the difference in location between the actual boundary <NUM> and the measured boundary <NUM> in an orthogonal direction to the imaging beam <NUM>. However, while vector <NUM> of <FIG> may represent the direction from the actual boundary to the measured boundary, vectors <NUM> are opposite. Vectors <NUM> extend from the measured boundary <NUM> to the actual boundary <NUM>. In this way, <FIG> may illustrate an additional embodiment of the present disclosure. Specifically, the vector denoting displacement from an actual boundary to a measured boundary, as in <FIG>, may be calculated as D(x) = K σ(x), as will be discussed in more detail hereafter. A vector denoting displacement from a measured boundary to an actual boundary, as in <FIG>, may be calculated as -D(x) = -K σ(x). In some embodiments, the vectors <NUM> and/or vector <NUM> of <FIG> may be referred to as point spread function width-dependent lateral border correction vectors and may be determined at each or any point of the chamber surface both from the measured boundary to the actual boundary and vice versa. Vectors <NUM> extend only in a lateral, orthogonal, or perpendicular direction to the ultrasound imaging beam <NUM>. As further illustrated in <FIG>, the magnitudes of vectors <NUM> depend on the depth of the corresponding location within the patient (e.g., relative to the ultrasound probe) and is directly proportional to the magnitude of the ultrasound point spread function illustrated by Gaussian curves <NUM>, Gaussian714, and Gaussian716.

Similar to the ultrasound point spread function previously discussed, vectors <NUM> may be defined or modelled as a function dependent on x, the distance of a point from the ultrasound probe. For example, any one of vectors <NUM> may be modelled as a function -D(x), where D(x) may be defined as D(x) = K σ (x). The function D(x) may be defined as how far a border detected purely parallel the ultrasound beam would be displaced laterally from the anatomical border. Due to its dependence on K, the function D(x) is typically specific to the anatomy and ultrasound acquisition type and can be modelled as a simple multiplier to the value of σ as shown. σ(x) is representative of the Gaussian function used to model the ultrasound point spread function PSF(x). K may be any suitable constant value. For example, K may be a calibrated value dependent on any number of suitable characteristics of or relating to anatomical structure <NUM>, such as the density, mass, volume, orientation, surface continuity, or any other suitable feature of anatomical structure <NUM>, or any liquid or gas within or around anatomical feature <NUM>. In some embodiments, ultrasound imaging system <NUM> may store constant K within memory <NUM> (<FIG>), or access constant K from a list stored in a separate server, computer, or cloud-based storage device, or any other suitable location. In other embodiments, constant K may be calculated or calibrated in a point-of-care setting, before or during an imaging procedure, or at any other suitable time or location. Constant K may additionally be manually input to ultrasound imaging system <NUM> by a system manufacturer or a user or supplied in any other suitable manner. In some embodiments, constant K may be calibrated according to the acquisition and anatomy type related to anatomical feature <NUM> or any other anatomical object measured with ultrasound imaging system <NUM>. Calibration of constant K will be discussed in more detail with respect to <FIG> hereafter.

Additionally, depicted in <FIG> is a plurality of correction vectors <NUM>. Correction vectors <NUM> may be similar to correction vector <NUM> (<FIG>). Similar to correction vector <NUM>, correction vectors <NUM> may represent a distance and direction from measured boundary <NUM> to actual boundary <NUM> in a direction normal to the surface of anatomical structure <NUM>. Correction vectors <NUM> need not be oriented orthogonal to the direction of ultrasound imaging beam <NUM> because the direction of correction vectors <NUM> are dictated by the orthogonal direction of the surface of anatomical structure <NUM> at various locations. The magnitude of correction vector <NUM> may represent the extent to which the point spreading effect caused by convolving a scatterer map with a point spread function applies in a direction normal to the boundary <NUM> and represents an approximation of the distance the measured boundary <NUM> varies from the actual boundary <NUM>. In some embodiments displacement vectors , or vectors extending from an actual boundary to a measured boundary, are of equal but opposite magnitude and direction than correction vectors. For example, correction vectors like vector <NUM> of <FIG> may be calculated as a function C(x) = (-N(x) · D(x))N(x), where D(x) may be defined as D(x) = K σ(x) and is equal to vector <NUM> of <FIG>, and N(x) represents a surface normal vector with respect to actual boundary <NUM>. C(x) may therefore represent a vector approximating the direction and distance from measured boundary <NUM> to actual boundary <NUM> at any point within, along, or around anatomical structure <NUM>. Any suitable form of C(x) may therefore be applied to measured positions of anatomical structure <NUM> to provide to a user of ultrasound imaging system <NUM> correct positions, measurements, and/or other relevant values. In this manner, correction vectors <NUM> shown in <FIG> may be similarly calculated or approximated as C(x) = (-N(x) · D(x)N(x) and may denote a direction and magnitude from the measured boundary <NUM> to the actual boundary <NUM>. This advantageously remedies the inaccuracies inherent within convolved ultrasound imaging applications without the need of deconvolution or other implementations. Because the magnitude and direction of each of the correction vectors <NUM> , each correction vector <NUM> may be dependent or based on the depth of the corresponding location of the vectors and/or the orientation of the measured boundary at the corresponding location relative to the ultrasound beam <NUM>.

Additionally, depicted in <FIG> is vector <NUM> and correction vector <NUM>. Vector <NUM> may be substantially similar to vectors <NUM> and/or may be included within the set of vectors <NUM> in that vector <NUM> extends in a direction perpendicular to the direction of propagation of the ultrasound imaging beam <NUM> and corresponds to the magnitude of the spreading effect of the ultrasound point spread function as illustrated by Gaussian curves <NUM>, <NUM>, and <NUM>. It is noted that vector <NUM> is of a very similar but slightly larger magnitude than the vector <NUM> adjacent to it in <FIG> because vector <NUM> corresponds to a point farther from the position of probe <NUM> than the adjacent vector <NUM>. However, vector <NUM> points in the same direction as the adjacent vector <NUM>. By contrast, correction vector <NUM> is of a magnitude much smaller than the adjacent correction vector <NUM> and in a different direction. Correction vector <NUM> may be substantially similar to correction vectors <NUM> and may be included within the set of correction vectors <NUM>. Correction vector <NUM> extends in a direction perpendicular to the surface of the anatomical structure <NUM>. The magnitude of correction vector <NUM> depends on a constant calibrated value associated with the structure, the skew angle of the boundary in relation to the direction of the ultrasound imaging beam <NUM>, and the distance of the location from the origin of the ultrasound imaging beam <NUM>. Although the effect of the ultrasound point spread function is greater at the location of correction vector <NUM> than at the location of the adjacent correction vector <NUM>, because the boundary <NUM> at the location of correction vector <NUM> is substantially more perpendicular to the direction of the ultrasound imaging beam <NUM> than boundary <NUM> at the location of the adjacent correction vector <NUM>, correction vector <NUM> has a smaller magnitude than the adjacent correction vector <NUM>. Similarly, a vector (corresponding to vector <NUM> or correction vector <NUM>) at a point <NUM> on or along boundary <NUM> of structure <NUM> would have a magnitude of zero or be extremely negligible because boundary <NUM> at that location is almost completely perpendicular to the direction of ultrasound imaging beam <NUM>. In other words, for a given depth from the ultrasound probe <NUM>, the correction vector <NUM> and correction vector are larger when the orientation of the measured boundary is more parallel to the ultrasound imaging beam <NUM> and they are smaller when the orientation of the measured boundary is more perpendicular to the ultrasound imaging beam <NUM>.

<FIG> is a diagrammatic view of a display of an ultrasound image <NUM> created by ultrasound imaging system <NUM>, according to aspects of the present disclosure. <FIG> illustrates the ultrasound image <NUM> in the context of calibrating the constant K value related to a specific anatomical feature (e.g., anatomical structure <NUM> of <FIG> or any other anatomical structure <NUM> of <FIG>). The constant K and, by dependence, the function D(x) must typically be calibrated according to the acquisition and anatomy type. In some embodiments, an ultrasound phantom <NUM> may be used and imaged by ultrasound imaging system <NUM> as one or more steps or substeps of a method of calibrating a constant Kcorresponding to the anatomical object. For example, in some embodiments, ultrasound phantom <NUM> may be any suitable ultrasound phantom having characteristics or echogenicity similar to the anatomical object to be imaged by ultrasound imaging system <NUM>, including but not limited to a water phantom, agar phantom, gelatin phantom, guar gum-based phantom, Blue Phantom®, <NUM>-D printed phantoms, and other phantoms. Phantoms may also include natural anatomical phantoms such as a meat phantom of any suitable test subject, including a cadaver. In some embodiments, and as shown in <FIG>, the ultrasound phantom <NUM> may be a hypoechoic egg phantom. In some embodiments, an ultrasound phantom <NUM> of known volume with any appropriate desirable characteristics may be measured at various depths using the ultrasound imaging system <NUM> in the same acquisition type and the ultrasound image <NUM> may be generated. A measured boundary <NUM> corresponding to the features and structures of ultrasound phantom <NUM> may be generated and displayed to a user of ultrasound imaging system <NUM> as illustrated in <FIG>.

<FIG> is diagrammatic view of an enlarged portion of the ultrasound image <NUM> of <FIG>, according to aspects of the present disclosure. The ultrasound image <NUM> in <FIG> includes measured boundary <NUM> and actual boundary <NUM>. To calibrate a constant Kcorresponding to a predetermined anatomical structure, ultrasound imaging system <NUM> may utilize a least squares optimization process to minimize the difference between the known volume of ultrasound phantom <NUM> and a volume calculated by ultrasound imaging system <NUM> based on the actual boundary <NUM> generated by ultrasound imaging system <NUM>. During this process, ultrasound imaging system <NUM> may find a value of constant K which produces the least error between these two volumes to serve as an approximation of a similar K to be applied when imaging anatomical objects with similar characteristics or echogenicity to the ultrasound phantom <NUM>. This K value may then be incorporated into an application which quantifies the volume of a similar structures such as a heart's left ventricle, as shown and further discussed in <FIG>. It is noted that the least squares minimization process is simply an exemplary method used by ultrasound imaging system <NUM>. Many additional methods of calculating a constant K may be utilized by ultrasound imaging system <NUM> by comparing known volumes with calculated volumes based on a plurality of perspective actual boundaries <NUM>, including but not limited to ordinary least regression, nonlinear regression, polynomial regression, logistic regression, quantile regression, or any other suitable data fitting or regression analysis method, approximation, or future developed method or algorithm.

<FIG> is a diagrammatic view of a screen display including an ultrasound image <NUM> created by the ultrasound imaging system <NUM>, according to aspects of the present disclosure. <FIG> may further depict an exemplary display of an anatomical structure <NUM> as represented by a measured boundary <NUM> and an actual boundary <NUM>. The anatomical structure <NUM> shown in <FIG> may be any suitable structure included previously. The anatomical structure <NUM> depicted in <FIG> may be a heart's left ventricle. The actual boundary <NUM> can be a corrected boundary that is generated by the ultrasound imaging system to correct errors in the measured boundary <NUM>. This actual boundary <NUM> may be graphically overlaid over the ultrasound image <NUM>. The actual boundary <NUM> may be calculated using a constant K calibrated with a method substantially similar to that described with reference to <FIG>. The anatomical structure <NUM> may be substantially similar to anatomical feature <NUM> or may exhibit similar characteristics including similar acoustic impedances of materials as ultrasound phantom <NUM> described in <FIG>. In addition, actual boundary <NUM> may be exhibit substantially similar characteristics or features as actual boundary <NUM> of <FIG>. Measured boundary <NUM> may be similar to measured boundary <NUM> (<FIG>).

As illustrated in <FIG>, ultrasound imaging system may display a plurality of lines reflecting boundaries such as actual boundary <NUM> and measured boundary <NUM> within ultrasound image <NUM>. These additional lines may correspond to boundaries of or relating to anatomical structure <NUM> or may correspond to additional anatomical structures or features surrounding, within, in connection with, or otherwise related to anatomical feature <NUM>. In some embodiments, ultrasound imaging system <NUM> may display both lines corresponding to actual boundaries <NUM> and lines corresponding to measured boundaries <NUM>. The ultrasound image <NUM> can include a graphical overlay of the actual boundary <NUM> and/or the measured boundary <NUM>. The graphical overlay can visually accentuate the actual boundary <NUM> and/or the measured boundary <NUM> within the image by identifying and/or highlighting the boundary relative to other anatomical features within the image. In other embodiments, ultrasound imaging system <NUM> may display to a user only lines corresponding to measured boundaries <NUM>. In other embodiments, ultrasound imaging system <NUM> may display to a user only lines corresponding to actual boundaries <NUM> and a user may discern a difference between the actual boundary <NUM> displayed and features of ultrasound image <NUM> indicating a measured boundary.

Any number or type of metrics <NUM> may additionally be displayed within or around ultrasound image <NUM>. The metrics <NUM> can include values associated with the measured boundaries <NUM> and/or the modified/actual boundary <NUM>. Metrics <NUM> may correspond to one or more volumes relating to significant features, cavities, or structures of or relating to anatomical structure <NUM>. In addition, dimensions of a structure <NUM> or other anatomical object <NUM> such as length, height, depth, width, circumference, diameter, radius, or other relevant dimension may be displayed to a user. Metrics <NUM> may further include any other suitable metric. Metrics <NUM> may be displayed overlaid over ultrasound image <NUM> as shown in <FIG>, or may alternatively be displayed to the right, left, above, or beneath ultrasound image <NUM>.

It is further noted that ultrasound image <NUM>, and any other ultrasound image, including ultrasound image <NUM>, may be displayed to the user as a video or in video-like format in real time in a point-of-care setting. Alternatively, ultrasound imaging system <NUM> may capture video comprising a plurality of ultrasound image frames and save images and/or videos within memory <NUM>. Any saved images or videos may further comprise biographical or other information relating to patients or any other suitable information. In other embodiments, ultrasound image <NUM>, ultrasound image <NUM>, and any other ultrasound image previously mentioned in the present disclosure may be only static images. In some embodiments, although two-dimensional images may be illustrated throughout the present disclosure, data corresponding to three-dimensional images, videos, or models may be captured, stored, saved, and/or analyzed by ultrasound imaging system <NUM> in substantially the same manner as set forth herein.

<FIG> is a flow diagram of a method <NUM> which may be employed by ultrasound imaging system <NUM> to correct inaccuracies in an ultrasound image, according to aspects of the present disclosure. 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. One or more steps of method <NUM> can be carried out by any suitable processor circuit or processing component (e.g., processor circuit <NUM>, processor circuit <NUM>, and/or processor circuit <NUM>).

At step <NUM>, method <NUM> includes receiving, from ultrasound probe <NUM>, ultrasound imaging data corresponding to a structure within a patient. The structure may be substantially similar to structure <NUM>, anatomical structure <NUM>, structure <NUM>, or any other suitable structure. As previously stated, a structure may be any suitable organ, muscle, tissue, and/or man-made or natural structure within a patient's anatomy. In some embodiments, the method <NUM> includes the processor circuit generating an ultrasound image or video based on the ultrasound imaging data.

At step <NUM>, method <NUM> includes determining a location of a measured boundary of the structure to be measured by ultrasound imaging system <NUM>. The measured boundary may be substantially similar to boundaries previously identified in the present application. For example, the measured boundary may be substantially similar to measured boundary <NUM>, measured boundary <NUM>, measured boundary <NUM>, or measured boundary <NUM> previously mentioned. In some embodiments, the measured boundary may be any suitable boundary between two media within a patient or within any other structure. The location of the measured boundary may be determined by ultrasound imaging system <NUM> using methods previously identified in the present disclosure. For example, acoustic waves may be emitted from probe <NUM> and reflect off of various structures within a patient or in any other suitable environment. Reflected acoustic waves may then be measured by probe <NUM> or any other equivalent component within an ultrasound imaging system to determine the location of the measured boundary. As noted, the location of the measured boundary will be subject to the blurring effect inherent in the ultrasound imaging point spread function. This effect is observed in all directions perpendicular to the direction of wave propagation of waves emitted by probe <NUM>. This blurring effect increases with depth, as previously discussed, making it difficult to determine the exact location of a measured boundary in an environment imaged by ultrasound imaging system <NUM>.

At step <NUM>, method <NUM> includes calculating and applying a correction vector normal to the measured boundary to determine a corrected boundary at a point along the measured boundary. This correction vector may be substantially similar to correction vector <NUM>. The correction vector <NUM> represents the distance and direction from a point on a measured boundary back to a point on the actual or corrected boundary. In some embodiments, the correction vector may be calculated based on a surface normal vector relative to the measured boundary, a previously calibrated value corresponding to the acoustic properties of the structure to be measured, the properties of the ultrasound point spread function associated with ultrasound imaging system <NUM> and/or the environment, and/or the distance from the selected location along the measured boundary from probe <NUM>. In other embodiments, the correction vector may be calculated based on additional variables or measurements or may not require all of the mentioned variables or measurements.

At step <NUM>, method <NUM> includes outputting, to a display, an ultrasound image including the measured boundary and/or the calculated corrected boundary of the structure. A plurality of correction vectors may be applied at any suitable location along a measured boundary within an ultrasound image to create a corrected boundary. The corrected boundary within an ultrasound image may be displayed to a user with a display substantially similar to display <NUM> of <FIG>. The corrected boundary may additionally be displayed to a user in any suitable format. For example, corrected boundary may be displayed as a single line extending substantially parallel to an additional line representing the measured boundary. In addition, the lines may be distinguished by using different colors, patterns, such as dotted lines or lines comprising different shapes or patterns of propagation. In some embodiments, a measured boundary may not be displayed. In some embodiments, the measured boundary may be identified by its associated blurred scatterers within an ultrasound image. In some embodiments, the corrected boundary may be displayed as a single line or a plurality of lines which may correspond to ranges of accuracy or certainty or may denote any other suitable characteristic or feature of the boundary within the structure. A wide variety of methods of displaying both the measured boundary and the corrected boundary are fully contemplated and may be used to convey to a user the locations of the corrected boundary and/or the measured boundary.

<FIG> is a diagrammatic view of an anatomical structure <NUM> within a patient displayed in cartesian space, according to aspects of the present disclosure. Anatomical structure <NUM> may be substantially similar to previously mentioned structures, including structure <NUM>, anatomical structure <NUM>, structure <NUM>, or any other suitable structure. Structure <NUM> may be any suitable organ, muscle, tissue, natural and/or man-made structure within a patient's anatomy. <FIG> depicts a plurality of arrows corresponding to acoustic waves of an ultrasound imaging beam <NUM> emitted by the ultrasound probe (e.g., probe <NUM> of <FIG>) that is positioned at the top of the image. In some embodiments, ultrasound imaging beam <NUM> may propagate in a diverging manner, in different directions from a common point corresponding to the location of the probe. In cartesian space, the ultrasound imaging beams have some angular width so that in the nearfield close to the origin of the imaging beams, the angular width is thin. However, in the far field, farther away from the origin of the imaging beams, the angular width widens considerably resulting in increased spreading farther away from the probe. In some embodiments, an ultrasound imaging beam may propagate in substantially one uniform direction such that arrows corresponding to the beam direction may be parallel to one another. In some embodiments, in cartesian space (<FIG>), the ultrasound imaging beam appears to be diverging from a common point while in polar space, the same ultrasound imaging beam appears parallel. <FIG> further depicts a plurality of points or scatterers <NUM>. Scatterers <NUM> are representative of components within that anatomy that reflect acoustic waves emitted by probe <NUM>. These ultrasound echoes are subsequently received or measured by ultrasound probe. As shown in <FIG>, the anatomical structure includes an inner boundary <NUM> and an outer boundary <NUM>. Only a portion of the anatomical structure <NUM> may be depicted in <FIG>. For example, a boundary may exist at a location farther from the ultrasound probe than depicted in ultrasound image <NUM> (e.g., past the bottom of the image in <FIG>). This border may be perpendicular to the direction of beam propagation such that anatomical structure <NUM> is a substantially closed structure.

<FIG> is a diagrammatic view of the anatomical structure <NUM> of <FIG> as measured by an ultrasound imaging system, according to aspects of the present disclosure. Like <FIG>, <FIG> also depicts the anatomical structure <NUM> in cartesian space. <FIG> differs from <FIG>, however, in that the effect of the ultrasound point spread function is illustrated in the form of scatterers <NUM> being blurred. The effect shown in <FIG> is generally what is measured by an ultrasound imaging system. The spreading of the scatterers from the perspective of the ultrasound imaging system leads to inaccuracies because it is difficult to ascertain the actual location of boundaries <NUM> and <NUM> within structure <NUM>. As described above, because the ultrasound point spread function is depth-dependent, the scatterers <NUM> that are located farther from the ultrasound probe (the scatterers <NUM> towards the bottom of the image in <FIG>) are more severely blurred, while scatterers <NUM> closer to the ultrasound probe (the scatterers towards the top of the image in <FIG>) are not as dramatically affected. The present disclosure describes techniques for correcting these inaccuracies so that the actual location of the boundaries <NUM> and <NUM> can be determined and/or presented to the user.

<FIG> is a diagrammatic view of the anatomical structure <NUM> of <FIG> displayed in polar space, according to aspects of the present disclosure. As previously discussed, in polar space, arrows corresponding to ultrasound imaging beam <NUM> are substantially parallel to one another such that ultrasound imaging beam <NUM> appears to propagate in one uniform direction. <FIG> further depicts scatterers <NUM> without the previously discussed blurring effect of the ultrasound point spread function.

<FIG> is a diagrammatic view of the anatomical structure <NUM> of <FIG>, as measured by an ultrasound imaging system and displayed in polar space, according to aspects of the present disclosure. <FIG> depicts scatterers <NUM> subject to the blurring effect of the ultrasound point spread function, which gives rise to the inaccuracy inherent in determining the location of boundaries <NUM> and <NUM>. Such inaccuracy is readily apparent and more severe for boundaries within a structure which are positioned further away from probe <NUM> and which extend substantially parallel to the direction of propagation of ultrasound image beam <NUM>. According to the present disclosure, the ultrasound imaging system <NUM> provides an improved border detection by calculating and applying one or more correction vectors to boundary <NUM> or boundary <NUM>. This correction may be performed in polar space or cartesian space. Any of the above calculations of vectors, boundaries, or any other metric may be performed in either the cartesian or polar space.

<FIG> is a diagrammatic view of an anatomical structure <NUM> within a patient displayed in cartesian space, according to aspects of the present disclosure. Anatomical structure <NUM> may be substantially similar to previously displayed structures. Anatomical structure <NUM> may comprise a substantially closed structure such that it fully encloses and defines a space <NUM> within structure <NUM>. <FIG> also depicts a plurality of scatterers <NUM>. The anatomical structure <NUM> includes an inner boundary <NUM> and an outer boundary <NUM>. Anatomical structure <NUM> includes a point or location <NUM> at a location furthest away from ultrasound probe at which boundary <NUM> and boundary <NUM> extend in directions perpendicular to the direction of propagation of ultrasound imaging beam <NUM> as will be discussed in more detail with reference to <FIG>.

<FIG> is a diagrammatic view of the anatomical structure <NUM> of <FIG>, as measured by ultrasound imaging system <NUM> and displayed in cartesian space, according to aspects of the present disclosure. <FIG> depicts scatterers <NUM> subject to the blurring effect of the ultrasound point spread function, which gives rise to the inaccuracy inherent in determining the location of boundaries <NUM>, <NUM>. Such inaccuracy is readily apparent and more severe for boundaries within a structure which are positioned further away from probe (at the top of image in <FIG>) and which extend substantially parallel to the direction of propagation of ultrasound image beam <NUM>. However, at location <NUM> and at any similar locations along a boundary of a structure in which a boundary of a structure extends in any direction perpendicular to the direction of propagation of ultrasound imaging beam <NUM>, the inaccuracy of determining the location of the boundary is negligible to non-existent. For example, at location <NUM>, though scatterers <NUM> are still subject to the ultrasound point spread function such that they are blurred, because the blurring occurs only in directions perpendicular to the direction of beam propagation and because the boundary extends in this same direction, no blurring occurs in the direction of beam propagation. At such locations, although ultrasound imaging system <NUM> may still calculate and apply a correction vector to measured boundary <NUM> or <NUM>, the magnitude of the correction vector will be zero or at most negligible. <FIG> therefore illustrates the ability of ultrasound image system <NUM> to more accurately determine the location of the actual boundary within a structure of a patient by making a location specific correction at any point along the surface of the boundary. This correction accounts for the distance of the location from the probe and the skew angle of the boundary in relation to the direction of beam propagation. This correction then yields significantly more accurate measurements of any number of metrics obtained in an ultrasound examination.

Claim 1:
An ultrasound imaging system (<NUM>), comprising:
a processor circuit (<NUM>, <NUM>) configured for communication with an ultrasound probe (<NUM>), the processor circuit configured to:
receive, from the ultrasound probe, ultrasound data representative of an ultrasound beam (<NUM>, <NUM>, <NUM>, <NUM>) imaging an anatomical structure (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
determine, based on the ultrasound data, a measured boundary (<NUM>, <NUM>, <NUM>) of the anatomical structure, wherein the measured boundary includes a plurality of locations;
determine a plurality of correction vectors (<NUM>, <NUM>) corresponding to the plurality of locations of the measured boundary, wherein a magnitude of a respective correction vector is based on at least one of:
a depth of a corresponding location relative to the ultrasound probe; or
an orientation of the measured boundary at the corresponding location relative to the ultrasound beam;
apply the plurality of correction vectors to the plurality of locations of the measured boundary to determine a corrected boundary (<NUM>, <NUM>, <NUM>); and
output, to a display (<NUM>) in communication with the processor circuit, an ultrasound image (<NUM>, <NUM>) based on the ultrasound data, wherein the ultrasound image includes the corrected boundary; and
being characterized in that
the plurality of correction vectors are configured to correct an effect of a point spread function of the ultrasound imaging system.