Ultrasound system and method for shear wave elastic imaging of anisotropic tissue

Abstract

The present disclosure includes ultrasound systems and methods for imaging anisotropic tissue at various angles relative to the tissue using shear wave elastography. An exemplary ultrasound imaging system includes: a probe coupled to a position tracking system, the position tracking system being used to track the position of the probe relative to an object; and a processor in communication with the probe. The processor can receive position tracking data from the position tracking system. The processor can: define at least one target plane in the anisotropic tissue, determine a difference between a current position of the probe and a position of the target plane, and provide a visual indicator of the difference, wherein the processor dynamically updates the visual indicator in response to a change in the position of the imaging plane relative to the target plane.

Description

Technical Field

[0001] The present disclosure relates to ultrasound systems and methods for imaging anisotropic tissue at various angles relative to the tissue using shear wave elastography. Background Art

[0002] Ultrasound imaging systems, such as cart-based ultrasound imaging systems, typically include a user interface that operates in conjunction with a probe and a display to acquire and display images from an object, such as a patient. Ultrasound imaging systems can use shear wave elastography to determine mechanical properties of tissue. Shear wave elastography can be used for screening and diagnostic purposes, such as to identify areas of abnormal stiffness in tissue, which can indicate the presence of, for example, a tumor.

[0003] Different types of tissues have different properties. Certain types of tissue (e.g., liver tissue) may generally be isotropic, while certain other types of tissue (e.g., musculoskeletal, vascular wall, and myocardial tissue) may be anisotropic, where the properties of the tissue (e.g., stiffness) may vary based on the direction in which the properties are measured. In order to characterize the properties of anisotropic tissue, it may be necessary to use a probe for measurement in more than one orientation relative to the tissue. However, it may be difficult for an operator to accurately control or record the direction of the probe. The examples described herein may provide solutions to one or more challenges in the field of anisotropic tissue imaging. Summary of the invention

[0004] The present disclosure relates to ultrasound systems and methods for imaging anisotropic tissues at various angles relative to the tissue using shear wave elastography. In at least one aspect, the present disclosure relates to an ultrasound imaging system for shear wave imaging. The ultrasound imaging system may include a probe and a processor. The probe may send and receive ultrasound echo signals to generate a shear wave image of anisotropic tissue of an object. The probe may be coupled to a position tracking system for tracking the position of the probe relative to the object. The processor may communicate with the probe and be configured to receive position tracking data from the position tracking system. The processor may define at least one target plane in the anisotropic tissue at an angle relative to a reference plane of the anisotropic tissue. The processor may determine a difference between a first position of an imaging plane of the probe at a position indicated by the position tracking data and a second position of at least one target plane. The processor may also provide a visual indicator of the difference on a display of the ultrasound system, and dynamically update the visual indicator in response to a change in the position of the imaging plane relative to the target plane.

[0005] In at least one aspect, the present disclosure relates to shear wave imaging. The method may include determining the position of a probe relative to an imaging plane of anisotropic tissue based on position tracking data generated at least in part based on sensor data received from a position sensor coupled to the probe. The method may include defining at least one target plane and / or determining a difference between the position of the imaging plane and the position of at least one target plane. The method may also include providing a visual indicator of the determined difference on a display and dynamically updating the visual indicator in response to a change in the position of the imaging plane. The method may include generating at least one shear wave image of the target plane using the probe.

[0006] Aspects of the present disclosure, such as specific elements of the user interface described herein and / or functions performed by a processor of an ultrasound system, may be embodied in a computer-readable medium including processor-executable instructions. For example, processor-executable instructions for providing one or more graphical user interfaces or elements thereof may be incorporated into a software package, for example for running on an analysis workstation. Aspects of the present disclosure may facilitate offline image analysis as further described below, but it should be understood that the principles described herein may be equally applicable to online image analysis (e.g., analysis performed during or shortly after image acquisition). According to one embodiment, a non-transitory computer-readable medium including processor-executable instructions for displaying an ultrasound image may include instructions for the following operations: displaying a first image frame from a first plurality of stored image files, wherein the image file includes first position information corresponding to a probe position during acquisition of the first image frame; receiving a request for an orthogonal view via a user interface; comparing the first position information with position information for a second plurality of image files in the stored image files to identify one or more image frames in the second plurality of image frames associated with position information closest to the first position information; and displaying a representation of each of the one or more image frames as a candidate orthogonal view. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of a system for guided shear wave elastography of anisotropic tissue constructed according to some examples of the present disclosure.

[0008] Figure 2 is a block diagram of an ultrasound system according to some examples of the present disclosure.

[0009] Figure 3A , 3B , 3C, 3D, 3E, and 3F are illustrations of probe placement relative to anisotropic tissue according to some examples of the present disclosure.

[0010] Figure 4A and Figure 4Bis an illustration of a coordinate system associated with components of an exemplary system (eg, a probe and / or an electromagnetic field generator) according to some examples of the present disclosure.

[0011] Figure 5A , 5B and 5C are graphical user interface elements providing visual indicators according to some examples of the present disclosure.

[0012] Fig. 6A and 6B is an example shear wave elastography image of muscle tissue including position indicators according to some examples of the present disclosure.

[0013] Fig. 7A and 7B is a block diagram of a coordinate system associated with a probe and anisotropic tissue according to some examples of the present disclosure.

[0014] Figure 8 is a flow chart depicting a method of guided shear wave elastography of anisotropic tissue according to some examples of the present disclosure. DETAILED DESCRIPTION

[0015] The following description of specific embodiments is merely exemplary in nature and is in no way intended to limit the invention or its application or use. In the following detailed description of embodiments of the present system and method, reference is made to the accompanying drawings and specific embodiments of the described systems and methods are shown by way of illustration, and the accompanying drawings form a part of the embodiments. These embodiments are described in sufficient detail to enable those skilled in the art to practice the currently disclosed systems and methods, and it should be understood that other embodiments may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present system. In addition, for the sake of clarity, when it is obvious to those skilled in the art, the detailed description of certain features will not be discussed so as not to obscure the description of the present system. Therefore, the following detailed description should not be viewed in a restrictive sense, and the scope of the present system is defined solely by the claims.

[0016] The present technology is described below with reference to the block diagram and / or flowchart illustration of the method, device (system) and / or computer program product according to the present embodiment. It should be understood that the blocks of the block diagram and / or flowchart and the combination of the blocks of the block diagram and / or flowchart can be implemented by computer executable instructions. These computer executable instructions can be provided to a processor, controller or control unit of a general-purpose computer, a special-purpose computer, and / or other programmable data processing devices to produce a machine, so that the instructions run by the processor of the computer and / or other programmable data processing devices create a unit for implementing the function / action specified in one or more boxes of the block diagram and / or flowchart.

[0017] Certain difficulties in reliably acquiring shear wave elastography images of anisotropic tissue at a guide angle relative to the tissue may be addressed by examples herein, for example, by providing feedback to a user (e.g., an ultrasound examiner) regarding the position and / or proximity of an imaging plane of a probe to a desired or target imaging plane position, and in some cases, by providing instructions to adjust the position of the probe and thereby the position of the corresponding imaging plane in order to position the probe to acquire a target view of the anisotropic tissue. Additionally or alternatively, examples herein may enable data to be collected at one or more target planes, increase the reliability of probe placement during such data collection, and / or allow accurate documentation of probe placement during measurements.

[0018] Various types of tissues may have anisotropic properties. For example, skeletal muscle exhibits anisotropic mechanical properties, i.e., tissue stiffness varies with load direction. In order to fully characterize the stiffness of the muscle, multiple stiffness measurement points at different angles between the transducer imaging plane and the muscle fiber orientation are usually required (e.g., in-plane fibers and cross-section fibers as two extreme cases). Recent studies have shown that more diagnostic potential can be provided by performing multi-directional stiffness measurements over the entire imaging angle range. However, it may be challenging for ultrasound examiners to accurately manipulate the direction of the probe and determine the angle between the imaging plane and the muscle fiber direction. The ultrasound system and method for shear wave elastic imaging according to the present disclosure can facilitate the control of the shear wave imaging plane relative to the fiber orientation, thereby resulting in a more accurate assessment of muscle stiffness as a function of the load direction, which can achieve more complete, accurate, and standardized quantitative stiffness measurements of organs and tissues that exhibit anisotropic behavior. Although certain examples are described herein for musculoskeletal tissue, it should be understood that the principles of the present disclosure can be equally applied to any type of anisotropic tissue (e.g., vascular wall tissue, myocardium, etc.).

[0019] Devices, systems and methods according to embodiments of the present disclosure are intended to guide the position of a shear wave elastography system relative to a tissue (e.g., position and angle in space). The imaging system may include a probe that sends and receives ultrasonic pulses to form an image of the tissue in an imaging plane. A position measurement system (e.g., a position tracking system) coupled to the probe can determine the position of the imaging plane relative to a position measurement system coordinate system (a world coordinate system) in real time. Feedback about the position of the current imaging plane relative to the world coordinate system can be provided to a user of the system (e.g., via a graphical display) to guide the placement of the imaging plane and capture data at a determined position. The system can guide the user to position and reposition the imaging plane at various different locations around the tissue (e.g., by repositioning or rotating the probe). By recording images of B-mode, shear wave elastography and / or other modalities at multiple locations and recording the location at which each image was taken, the system can construct a more complete picture of anisotropic tissue properties.

[0020] Figure 1 An operating environment 100 associated with an ultrasound imaging system 112 according to some embodiments of the present disclosure is depicted. Components of the operating environment 100 may be used, at least in part, to implement embodiments of the present disclosure. For example, Figure 1 An ultrasound imaging system 112 is shown, which may include or be operably coupled to a probe 106, an ultrasound base 114, and a processing unit 118 (which may be located within the base in some embodiments), a position tracking system 116 may include a position field generator 117 and a sensor 108 connected to or operably associated with the probe 106, and a user 102 performing ultrasound imaging of an object 104 using the probe 106. Figure 1 The components shown in are illustrative only, and other variations, including removing components, combining components, rearranging components, and replacing components, are contemplated.

[0021] exist Figure 1In the operating environment 100 of the present invention, a user 102 can use a probe 106, which can be a part of the probe 106 and / or the probe 106 communicatively connected to the ultrasound imaging system 112 to perform ultrasound examination of anisotropic tissue 105 of an object 104, and more specifically, obtain an ultrasound shear wave elastic imaging image of the anisotropic tissue 105 of the object 104. The probe 106 can be arranged relative to the anisotropic tissue 105 so that it scans a measurement plane 110 including a cross-section of the anisotropic tissue 105. The probe 106 can include a sensor 108, which can be coupled to a position measurement system 116 to determine the position (e.g., spatial position and / or orientation) of the probe 106, thereby determining the position of the measurement plane 110. In one example, the sensor 108 can interact with an electromagnetic field generated by a field generator 117 of the position measurement system 116 to determine the position of the sensor 108. In other examples, the position measurement system 116 may involve optical tracking (e.g., an optical sensor records the position of an optical marker on the probe), mechanical tracking (e.g., connecting the probe to a robotic arm, a rigid stereotaxic frame), and / or ultrasound image-based tracking. Other position measurement or tracking systems may be used in other embodiments. The probe 106 may be coupled to an image data acquisition component that may be located in an imaging base 114 of the image to acquire image data on the measurement plane 110.

[0022] The ultrasound system 112 includes an ultrasound base 114 coupled to the probe 106 and a processing unit 118. The processing unit 118 may receive data about the position of the probe 106 from the position tracking system 116 and / or the sensor 108, and may receive measurement data from the ultrasound base 114. In some embodiments, the processing unit 118 may be a computer coupled to the ultrasound base 114. The ultrasound system 112 may include a display 120, a processor 126, a controller 128, and a memory 130 including instructions 132, which may include one or more steps 133a-133e. The processor 126 and / or the controller 128 may operate based on the instructions 132 to analyze information and / or control the ultrasound system 112. The display 120 may display at least one image 124 and / or one or more visual indicators 122 based on the measurement data from the ultrasound imaging system 112 and / or the position data from the sensor 108 and / or the position tracking system 116.

[0023] The probe 106 can be used to image a region of interest in a biological tissue, such as a region including anisotropic tissue 105. As described, anisotropic tissue is generally a tissue that can have different properties, for example, the tissue can have different stiffnesses depending on the orientation relative to the tissue to measure the property. In some examples, the anisotropic tissue 105 being imaged can be musculoskeletal tissue, myocardial tissue, vascular wall tissue, thyroid tissue, or any combination thereof. Of course, the examples herein can be applicable to other types of tissues beyond the specific examples described herein. One or more properties of anisotropic tissue 105, such as stiffness, can be measured and can be used to assess and / or diagnose conditions such as injury, malnutrition, and / or myositis.

[0024] The probe 106 can be used to acquire shear wave elastography images of the anisotropic tissue 105. To this end, the probe 106 can include a transducer that is operable to emit a "push pulse" to the anisotropic tissue 105, generating a shear wave that then propagates through the anisotropic tissue 105. Alternatively, shear waves in the tissue can be generated without acoustic radiation forces, but rather via mechanical forces applied externally to the tissue, such as by a mechanical vibrator configured to compress the tissue. The probe 106 can be further operable to emit tracking pulses that can be used to measure the velocity of the shear wave as it propagates. The measured velocity of the shear wave can be analyzed (e.g., by a processor 126) to determine the stiffness of the anisotropic tissue 105. The shear wave elastography data can be used to generate a shear wave elastography image.

[0025] The transducer of the probe 106 can be a linear (or one-dimensional) transducer, which is operable to receive data generally from a single imaging plane 110. In some embodiments, the linear probe can be phased or controllable in the azimuth direction to increase the field of view. Nevertheless, the linear transducer may need to be physically repositioned (e.g., tilted or heeled relative to the object, or rotated to a different orientation relative to the object) to collect image data in highly different imaging planes passing through biological tissue. When an object is imaged using a system according to an example of this article, the system can receive position data (including the spatial position (3D) of the probe and the direction of the probe) of the position of the specified probe 106 and thereby indicate the imaging plane relative to a reference system (e.g., the coordinate system of the position measurement system). As the inspection proceeds, for example, in order to collect images of different orientations relative to the tissue 105, the ultrasound system 112 can guide the user 102 to change the position of the probe 106, thereby changing the orientation of the imaging plane 110.

[0026] The probe 106 may be coupled to a position tracking system 116 to determine the position of the probe 106 relative to the position tracking system 116. The probe 106 may include at least one sensor 108 that may receive information from the position tracking system 116. The at least one sensor 108 may be attached to the probe 106 or may be integrated into the probe 106. The position tracking system may have a known spatial relationship with the object 104. In some examples, the position tracking system may be registered to the object 104, for example, by spatially registering the probe 106 to the object at the beginning of an ultrasound examination. As shown, the position tracking system 116 may include a position field generator 117 that generates a field that interacts with the at least one sensor 108. In one embodiment, the at least one sensor 108 may measure a property of the field. In another embodiment, the at least one sensor may generate a disturbance in the field that may be measured by the position field generator 117.

[0027] The measurements from the at least one sensor 108 and / or the position field generator 117 may be used to determine the position of each of the at least one sensor 108 relative to the position field generator 117. These measurements, in turn, may be used to determine the position of the probe 106 based on the known relationship between the position of each of the at least one sensor 108 and the probe 106. The measurements may be sent to the ultrasound system 112 to determine the position of the probe 106, or these calculations may be performed by a processor located in the position tracking system 116 or the probe 106. Although Figure 1 The position tracking system 116 is depicted as being coupled to the ultrasound system 112, but in some embodiments, the position tracking system 116 is not directly connected to the ultrasound system 112, and the sensor 108 of the probe 106 provides position measurements to the ultrasound system 112. The sensor 108 may be directly coupled to the ultrasound system 112, or may be indirectly coupled via the probe 106 and / or the position tracking system 116.

[0028] As described in more detail herein, position tracking system 116 may have a known relationship to the position of object 104 and / or anisotropic tissue 105, thereby allowing determination of the relationship between the position of probe 106 and the position of anisotropic tissue 105. In one example, position field generator 117 may be located beneath object 104, such as embedded in a mattress supporting object 104. In other examples, if it is assumed that tissue 105 is not moving relative to position measurement system 116, then determination of the relationship between probe 106 and anisotropic tissue 105 may not be required.

[0029] The position tracking system 116 may have a coverage area around the object 104 and / or the anisotropic tissue 105. The coverage area may define an area in which the position of the probe 106 may be determined. The size and shape of the coverage area may be determined by the properties of the position field generator 117. The coverage area may be defined by moving the probe 106 and marking different locations. As an example, the ultrasound system 112 may prompt the user 102 (e.g., via the display 120) to move the probe 106 to one or more set positions relative to the object 104. These positions may be the edges of the expected coverage area. The ultrasound system 112 may record the size of the desired coverage area and may subsequently provide feedback (e.g., via a tone and / or display 120) to indicate that the probe 106 is at or near the edge of the coverage area.

[0030] In some embodiments, the position tracking system 116 may be an electromagnetic tracking system. The position field generator 117 may be an electromagnetic field generator that generates an electromagnetic field about the object 104. The sensor 108 may be an electromagnetic sensor that detects a property (e.g., amplitude) of the electromagnetic field at the location of the sensor 108. The electromagnetic field generator may be a table-top electromagnetic generator and may be positioned on or near a structure (e.g., a gurney, an imaging table, a bed) supporting the object 104. Other forms of position tracking systems 116 and sensors 108 may be used in other embodiments.

[0031] exist Figure 1 In the example of , the ultrasound system 112 is communicatively coupled to the probe 106 and the position tracking system 116. The ultrasound system 112 can receive data from the probe 106 and the position tracking system 116 and / or can control them to change the operation of these components. The ultrasound system 112 can be provided as a mobile unit, such as on a cart, or as a portable handheld unit, such as a tablet computer. The probe 106 and / or the position tracking system can be coupled to the ultrasound system 112 via a wired and / or wireless (e.g., Wi-Fi, Bluetooth) connection. The ultrasound system 112 can have an ultrasound base 114 coupled to the probe 106. The ultrasound base 114 can control shear wave elastography sent by the transducer and receive data from the probe 106. Although Figure 1 The ultrasound pedestal 114 and the processing unit 118 are depicted as separate components of the ultrasound system 112, but it should be understood that the ultrasound pedestal 114 may share components with the processing unit 118, such as the processor 126, the controller 128, and the memory 130. In some embodiments, the ultrasound pedestal 114 and the processing unit 118 may be integrated into a single unit.

[0032] The ultrasound system 112 includes an operating unit 118 that is coupled to the probe 106 and the position tracking system 116 (via the ultrasound base 114). The operating unit 118 can receive shear wave elastography data from the probe 106 (and / or the ultrasound base 114) and generate one or more shear wave elastography images 124. The processor 126 can analyze the data from the probe 106, the sensor 108, and / or the position tracking system 116 using the instructions 132 (e.g., by executing step 133a) to determine the position of the probe 106. The position of the probe 106 can be determined in real time. The position and / or the image 124 can be additionally stored in the memory 130. The processor 126 can determine one or more target positions or planes on which to capture images (e.g., by executing step 133b of the instructions 132), and determine the difference between the current position of the probe 106 and the target plane (e.g., by executing step 133c). The processor 126 can operate the instructions 132 to generate one or more visual indicators 122 that depict the current position of the imaging plane 110 relative to the target plane of the anisotropic tissue 105 (e.g., by executing step 133d). When the probe 106 and the target plane are aligned, the processor 126 can execute the instructions 132 to generate a shear wave image (e.g., step 133e). The processing unit 118 may include a display 120 that displays the image 124 and / or the visual indicators 122. Although certain specific steps 133a-133e of the instructions 132 have been described, it should be understood that the instructions 132 may include more or fewer steps and that the steps may be repeated, rearranged, and / or selectively changed.

[0033] The processor 126 may generate one or more visual indicators 122 that may guide the positioning of the probe 106 so that the position of the imaging plane 110 matches the position of the target plane. The visual indicators 122 may provide feedback to the user 102 to manually adjust the position of the imaging plane 110 by moving the probe 106. The processor 126 may directly adjust the position of the probe 106 and / or the imaging plane 110 by generating instructions to update the position of the probe 106 and / or the imaging plane 110, and the controller 128 controls the actuator based on those instructions to adjust the position of the probe 106 and / or the imaging plane 110 to match the position of the target plane. The ultrasound system 112 may generate various target planes to guide shear wave elastic imaging of the anisotropic tissue 105 at various locations relative to the anisotropic tissue 105. The visual indicators 122 may improve the accuracy of positioning the probe 106 at each of the various locations.

[0034] The ultrasound system 112 can capture shear wave elastography images (data) along the imaging plane 110, and can also store and / or retrieve previously recorded data for later review. The images 124 and / or position data can be saved in the memory 130 and called up as needed. The ultrasound system 112 can classify different images based on the specific location where the data was collected, and can allow the user 102 to classify or select different images based on these classifications. For example, the ultrasound system 112 can have a "find orthogonal" tool that selects an image that is orthogonal to the currently displayed image. A report can be generated based on a selection of the saved data in the memory 130.

[0035] Figure 2 FIG. 2 is a block diagram of an ultrasound imaging system 200 according to some embodiments of the present disclosure. The ultrasound imaging system 200 may be used to at least partially implement Figure 1 Ultrasound system 112. Figure 2 An ultrasound imaging system 200 is shown, which includes an ultrasound probe 206, a transducer array 270, a microbeamformer 268, a transmit / receive (T / R) switch 250, a beamformer 252, a transmit controller 210, a signal processor 254, a B-mode processor 262, a scan converter 260, a multi-planar reformatter 266, a volume renderer 264, an image processor 258, a graphics processor 256, a user interface 274, an input device 272 and an output device 220. Figure 2 The components shown in are illustrative only, and other variations, including removing components, combining components, rearranging components, and replacing components, are contemplated.

[0036] The ultrasound imaging system 200 includes a probe 206. In some embodiments, the probe 206 can be used to implement Figure 1 The probe 106 is located around the subject and is used to capture data about the subject's tissue. Figure 2In the ultrasound imaging system 200, the ultrasound probe 206 includes a transducer array 270 for transmitting ultrasound and receiving echo information. Various transducer arrays are well known in the art, for example, linear arrays, convex arrays, or phased arrays. The transducer array 270 may, for example, include a two-dimensional array of transducer elements that can be scanned in height and azimuth dimensions for 2D and / or 3D imaging. The transducer array 270 is coupled to a microwave beamformer 268, which is typically positioned in the ultrasound probe 206, and the microwave beamformer 268 controls the transmission and reception of signals by the transducer elements in the array. In this example, the microwave beamformer 268 is coupled to a transmit / receive T / R switch 250, which switches between transmission and reception, for example, via a probe cable or wirelessly. The T / R switch 250 can therefore protect the beamformer 252 from the influence of high-energy transmission signals. In some embodiments, the T / R switch 250 and other elements of the system may be included in the transducer probe rather than in a separate ultrasound system base (eg, ultrasound base 114).

[0037] The transmission of ultrasound beams from the transducer array 270 is directed by a transmit controller 228 coupled to the T / R switch 250 and the beamformer 252 under the control of the microwave beamformer 268. The transmit controller 228 receives input from user operation of an input device 272 of a user interface 274. The transmit controller 228 may be a controller of an ultrasound system base (e.g., Figure 1 The ultrasound base 114 of the embodiment of the present invention may be a component of the ultrasound base 114 of the embodiment of the present invention, or may be a general controller of the ultrasound system (e.g., Figure 1 Controller 128). The user interface 274 can be implemented using one or more inputs (e.g., a control panel that can include soft and / or hard controls) and output devices (e.g., one or more displays), as further described below. One of the functions controlled by the transmit controller 228 is the direction in which the beam is steered. The beam can be steered straight forward from the transducer array (perpendicular to the transducer array), or at a different angle for a wider field of view. The partially beamformed signal produced by the microwave beamformer 268 is coupled to the beamformer 252, where the partially beamformed signals from the individual patches of transducer elements are combined into a fully beamformed signal. The transmit controller 228 can record the position of the beam relative to the probe 206. As described herein, the position of the beam and the probe 206 can be used to determine the imaging plane (e.g., Figure 1 The position of the imaging plane 110).

[0038] The beamformed signal may be coupled to a signal processor 254. The signal processor 254 may process the received echo signals in various ways, such as bandpass filtering, decimation, I and Q component separation, and harmonic signal separation. The processor 254 may also perform signal enhancement, such as ripple reduction, signal compounding, and noise elimination. The processed signal may be coupled to a B-mode processor 262, which may employ amplitude detection to image structures in the body. The signal generated by the B-mode processor may be coupled to a scan converter 260 and a multi-plane reformatter 266. The scan converter 260 arranges the echo signals in a desired image format according to the spatial relationship in which the echo signals are received. For example, the scan converter 260 may arrange the echo signals into a two-dimensional sector-shaped format, or a cone three-dimensional (3D) image. The multi-plane reformatter 266 is capable of converting the echoes received from points in a common plane in a volumetric region of the body into an ultrasound image of the plane, as described in U.S. Pat. No. 6,443,896 (Detmer). The volume renderer 264 converts the echo signals of the 3D data set into a projected 3D image as seen from a given reference point, for example, as described in U.S. Pat. No. 6,530,885 (Entrekin et al.). The 2D or 3D image may be coupled from the scan converter 260, the multiplanar reformatter 266, and the volume renderer 264 to the image processor 258 for further enhancement, caching, and temporary storage for display on the output device 220. The output device 220 may include a display device implemented using various known display technologies such as LCD, LED, OLED, or plasma display technology. In some embodiments, the output device 220 may implement Figure 1 Display 120.

[0039] The graphics processor 256 can generate graphic overlays for display with the ultrasound image. These graphic overlays can include standard identification information, such as the patient name, date and time of the image, imaging parameters, and the like. The graphics processor can receive input from an input device 272, such as a typed patient name. The input device 272 can include one or more mechanical controls, such as buttons, dials, trackballs, physical keyboards, and the like, which may also be referred to herein as hard controls. Alternatively or additionally, the input device 272 can include one or more soft controls, such as buttons, menus, soft keyboards, and other user interface control elements implemented, for example, using touch-sensitive technology (e.g., resistive, capacitive, or optical touch screens). To this end, the ultrasound imaging system 200 can include a user interface processor (i.e., processor 226) that can control the operation of the user interface, such as functions associated with the soft controls. One or more user controls can be co-located on a control panel. For example, one or more mechanical controls can be provided on a console, and / or one or more soft controls can be co-located on a touch screen that can be attached to or integrated with the console. For example, in some embodiments, the input device 272 can be Figure 1 The processing unit 118 and / or part of the ultrasound base 114.

[0040] The ultrasound images and associated graphical overlays may be stored in the memory 230, for example, for offline analysis. Additionally, the memory 230 may store processor-executable instructions including instructions for performing functions associated with the user interface 274. In some embodiments, the user interface 274 may include a graphical user interface that may be configured to display graphical user interface elements in response to a processor of the system 200, the graphical user interface elements being used to provide guidance to the sonographer to perform shear wave elastic imaging of anisotropic tissue in ultrasound imaging according to any of the examples herein. The memory 230 may be part of the ultrasound base unit, or may be a general purpose memory that is part of a computer system coupled to the base unit (e.g., the memory 230 may be a computer system that is coupled to the base unit). Figure 1 The user interface 274 may also be coupled to the multiplanar reformatter 266 for selecting and controlling the display of a plurality of multiplanar reformatted (MPR) images. In some examples, the functionality of two or more processing components (e.g., the beamformer 252, the signal processor 254, the B-mode processor 262, the scan converter 260, the multiplanar reformatter 266, the volume renderer 264, the image processor 258, the graphics processor 256, the processor 226, etc.) may be combined into a single processing unit, e.g. Figure 1 Processor 126.

[0041] The probe 206, sensor 208, microbeamformer 268, and transducer 270 may be combined into a handheld unit 276. The handheld unit 276 may be shaped to be held in the hand of a user. The handheld unit 276 may have a "head" or "face" that contains the transducer 270 and is shaped to be positioned on the surface of a subject (e.g., against the skin). In some embodiments, the sensor 208 may be implemented Figure 1 at least one sensor 108. Although Figure 2 Only one sensor 208 is shown in FIG. 2 , but it should be understood that sensor 208 may represent multiple sensors located around probe 206. Sensor 208 may be integral, such as contained within the housing of probe 206, may be a separate component attached to the exterior of the housing of probe 206, or may be a combination of integral and combined. Sensor 208 may be located at a fixed position relative to probe 206, such that by knowing the position of sensor 208, the position of probe 206 and the imaging plane is also known.

[0042] FIG. 3A to FIG. 3F Probe placement relative to anisotropic tissue according to an example of the present disclosure is shown. The position of the probe can be defined by the position of the planes that intersect the tissue. The relationship between these planes can be determined and can be used to guide the placement of the probe during one or more imaging operations. Figures 3A-3D Depicted are anisotropic tissue 305, fiber 334, probe 306, imaging plane 310, rotated imaging planes 310' and 310", reference plane 311, and at least one target plane 313 and 313a-313d. Figure 3A and 3C Depicted is the probe placed in two different positions relative to anisotropic tissue. Figure 3B and 3D Depicted in Figure 3A and 3C An imaging plane through the tissue captured by the probe at the location of the imaging plane. Figure 3E is a top view of the tissue, depicting the target plane 313. Figure 3F It is a top view similar to 3E, but there are multiple imaging planes 313a-313d. Figures 3A-3F The examples shown in are illustrative only, and other variations, including removing components, combining components, rearranging components, and replacing components, are contemplated.

[0043] In some embodiments, the probe 306 may be Figure 1Embodiments of probe 106. Probe 306 may be placed against a surface of a subject (e.g., on the skin) adjacent to an area of ​​anisotropic tissue 305. Anisotropic tissue 305 may include fibers 334, whose orientation may at least partially determine the anisotropic properties of anisotropic tissue 305. That is, a given property (e.g., stiffness) of tissue 305 may be different when measured with an imaging plane of probe 306 aligned with the direction of the fibers of tissue 305 than when measured with the imaging plane of probe 306 not aligned with the direction of the fibers. Probe 306 collects data from imaging plane 310, which may include a portion of anisotropic tissue 305. Reference plane 311 may be defined in the tissue, and an angle θ is measured between a current position of imaging plane 310 and a position of reference plane 311. One or more target planes 313 , 313 a - d may also be defined in the anisotropic tissue 305 , which may have an angle α relative to the reference plane and may have an angle β relative to the current imaging plane 310 .

[0044] Figure 3A A probe 306 for shear wave elastography of an area of ​​anisotropic tissue 305 is depicted. Anisotropic tissue 305 may include fibers 334. Fibers 334 may be generally aligned. Fibers 334 may have mechanical properties measured across the fibers that are different from the same mechanical properties measured along the fibers. In some cases, the orientation of fibers 334 may define anisotropic properties of anisotropic tissue 305. Fibers 334 may be, for example, muscle fibers. Probe 306 may collect data from an imaging plane 310 extending through the tissue.

[0045] Figure 3B A cross-sectional view of anisotropic tissue 305 is shown corresponding to imaging plane 310. In this example, imaging plane is shown as being generally aligned along the long axis of optical fiber 334. Fiber 334 extends across imaging plane 310. Imaging plane 310 is depicted as being generally rectangular, but other shapes of imaging plane 310, such as curvilinear, trapezoidal, fan-shaped, and / or radial, may be used in other examples.

[0046] Figure 3C and 3D Similar to Figure 3A -B, but the probe 306 is relative to its Figure 3A -B has changed position and is now collecting data from image plane 310'. Figure 3C and 3D , imaging plane 310′ is shown as being generally aligned on the long axis of fiber 334 (e.g., from Figure 3A -B rotated about 90°). Figure 3DThe image of 310 shows the fibers 334 moving in and out of the imaging plane 310'.

[0047] Figure 3E and 3F A simplified top view of the probe 306 and anisotropic tissue 305 is depicted. For reference, the anisotropic tissue 305 is shown in a top view even though it may be obscured (e.g., under the skin) and not visible. For clarity, the fibers of the anisotropic tissue 305 have been omitted from these figures, but it should be understood that the anisotropic tissue 305 may still have fibers, for example, which may extend from left to right in this view. A reference plane 311 can be defined relative to the anisotropic tissue 305, so that the position of the imaging plane 310 can be described relative to the position of the reference plane 311. In this example, the reference plane 311 is defined as a plane aligned with the long axis of the fiber 334 (e.g., Figure 3A-3B Since the position of the probe 306 is rotated relative to the position of the reference plane, the position of the case image plane 310' can be measured as the angle θ between the reference plane 311 and the image plane 310'. Figure 3E In the case of , the angle θ may be approximately 90°.

[0048] In some embodiments, reference plane 311 can be defined relative to one or more features of anisotropic tissue 305. Reference plane 311 can be aligned with a known anatomical structure (e.g., along the long axis of a bone or along the expected direction of muscle fibers). Reference plane 311 can be aligned with a feature of anisotropic tissue 305. Reference plane 311 can be aligned, for example, with the long axis of a fiber of muscle tissue. The system (e.g., Figure 1 The ultrasound system 112 of FIG. 1 may be used to determine the location of the reference plane 311. In an example, a 3D scan of the anisotropic tissue 305 may be performed and may be determined by the system (e.g., using Figure 1 The processor 126 of the apparatus 120 can identify anatomical features through techniques such as machine learning. The system can then define a reference plane 311 based on the identified anatomical features. In one embodiment, the system can estimate the direction of the fibers in the anisotropic tissue 305 based on the 3D scan and align the reference plane 311 with the long axis of the estimated fibers. Other methods of defining the reference plane 311 can be used in other examples.

[0049] In some embodiments, the reference plane 311 can be set by a user (e.g. Figure 1 The probe 306 may include a reference frame selector (e.g., a button). When the reference frame selector is activated, the ultrasound system (e.g., Figure 1 The ultrasound system 112 of the imaging plane 310 may record the current position of the imaging plane 310 as the reference plane 311. Figure 3A In the example of -F, the reference frame selector can be in the probe 306 when Figure 3A-3B Other methods for user selection of reference plane 311 may be used in other embodiments.

[0050] System (e.g. Figure 1 The ultrasound system 112) can be used to save images taken along the image planes 310', 310" and position information for each image relative to a reference plane 311 defined (e.g., each image can be associated with an angle θ). The system can include a "recalibrate reference plane" tool. The system can selectively allow a new reference plane to be selected for the saved images. The new reference plane can be selected from one of the saved images and can be selected by a user of the system. The system can update the position data saved with the image (e.g., by overwriting the old position data) to reflect the position of the image relative to the new reference plane. The "recalibrate reference plane" tool can be used to account for changes in the measurement position over time, for example, if the probe 306 moves during the measurement sequence.

[0051] Figure 3E and 3F The probe 306 is shown relative to the target plane 313 (at Figure 3E ) or relative to any of multiple target planes ( Figure 3F 310 ′ of the probe 306 should be aligned in order to acquire an image on the desired imaging plane. Figure 1 The ultrasound system 112 of the present invention may generate operator guidance (e.g., a graphical user element provides an indicator for one or more target planes) to assist the user in acquiring appropriate image data. The target planes 313, 313a-d may have a predetermined position relative to the reference plane 311. In some examples, the target plane 313 may be defined at a predetermined angle relative to the reference plane 311 (e.g., by the system and / or in response to user input). Multiple target planes 313a-d may be defined at set angular intervals relative to the reference plane. In one example, multiple target planes are defined at angular intervals of 15°, such that a first target plane is defined at 15° relative to the reference plane, and additional target planes are defined at angular increments of 15° relative to the previous target plane. Other angular intervals (e.g., 5°, 10°, 20°, 25°, etc.) may be used in other examples, and the user of the system may select the angular interval and range. In some examples, the system may be preset to define the target planes at given angular intervals, and the preset may be adjusted by the user in some cases.

[0052] The position of each target plane 313, 313a-d can be described relative to the reference plane 311. Figure 3E In the example of , when all planes are rotated around the axis, there may be an angle α between the position of the reference plane 311 and the position of the target plane 313. There may be an angle β between the current imaging plane 310 and the target plane 313. Similar to Figures 3A-3D , the reference plane 311 is selected to be aligned with the long axis of the fiber 334 of the anisotropic tissue 305. The target plane 313 has been selected to be at a position of approximately 45° (counterclockwise) from the reference plane 311. Therefore, in this example, the angle α can be approximately 45°. Other angles and positions of the target plane can be used in other examples.

[0053] The position of the imaging plane 310 can be adjusted to match the position of the target plane 313. This can take the form of reducing the angle β until it is approximately 0° or within a threshold of 0°. When the imaging plane 310 is aligned with the position of the target plane 313, a shear wave elastography image can be generated. When the imaging plane 310 is close to the target plane 313 (e.g., the angle β is below a selected threshold), a shear wave elastography image can be recorded. The shear wave elastography image can be recorded by the system (e.g., Figure 1 The current angle θ may also be recorded together with the shear wave elastography image. Figure 3E As shown in , the image plane 310' is currently at an angle θ of approximately 90° relative to the reference plane 311. The current position of the imaging plane 310' can match the position of the previous target plane. The imaging plane 310' may need to be rotated approximately -45° (e.g., 45° clockwise) to align with the position of the target plane 313. Although only one target plane 313 and one rotation are shown in this example, the position of the imaging plane 310 can be rotated again to match the next target plane. Other rotations and target plane positions are used in other examples.

[0054] Figure 3F Similar to Figure 3E , but in Figure 3F In the embodiment of FIG. 1 , the system has generated multiple target planes 313a-313d, and the probe 306 is rotated so that the imaging plane 310″ is aligned with the target plane 313a-313d. FIG. 3A to FIG. 3E The imaging planes 310 and 310' have different positions. Figure 3F In, with Figures 3A-3ESimilarly, a reference plane 311 has been defined that is aligned along the axes of the fibers of the anisotropic tissue 305. The ultrasound imaging system can generate a plurality of target planes 313a-d and then generate instructions to position the imaging plane 310 to align with each of the plurality of target planes 313a-d in the sequence. The system can command the target planes 313a-d of the sequence to minimize movement of the probe 306 between each alignment of the sequence. Figure 3F In the example shown, an ultrasound system (e.g., Figure 1 The ultrasound system 112 of FIG. 1 has generated four target planes 313a-d relative to the reference plane 311. Each target plane 313a-313d is spaced at an angle of approximately 22.5°. Therefore, measured clockwise from the reference plane 311, the target plane 313a is approximately 22.5°, the target plane 313b is approximately 45°, the target plane 313c is approximately 67.5°, and the target plane 313d is approximately 90°. Although the target planes 313a-d have been shown at regular rotational intervals, it should be understood that the target planes can be generated based on a variety of criteria. In some examples, the target planes can be irregularly spaced. In some examples, other position changes other than rotation can be indicated. Similarly, although only four target planes 313a-d are shown in this example, it should be understood that the system can generate more or fewer target planes.

[0055] like Figure 3F As shown, the probe has been rotated so that the current imaging plane 310" is aligned with the first target plane 313a. Once the system (e.g., Figure 1 Once the ultrasound system 112) records an image at that location (automatically or after prompting the user to save the image), the system can be updated to generate directions to position the probe 306 to align with the next target plane 313b. Thus, the system can generate instructions indicating that the probe 306 should be rotated 22.5° from the position of the current imaging plane 310" to the position of the target plane 313b. After an image is captured at each target plane 313a-d, the process can be repeated until the system indicates that there are no target planes remaining.

[0056] Figures 4A-4B Other aspects of the present disclosure are shown, and more particularly, coordinate systems associated with probes and / or other components of the system. Figure 4A -B shows the probe 406, anisotropic tissue 405, fiber 434, position tracking system 416, position coordinate system 440, reference coordinate system 442, target coordinate system 444, and current coordinate system 446. In certain embodiments, the probe 406 may be Figure 1 An embodiment of the probe 106. Figures 4A-4BThe examples shown in are illustrative only, and other variations, including removing components, combining components, rearranging components, and replacing components, are contemplated.

[0057] Figures 4A-4B The coordinate system shown can be defined and used by the ultrasound system (e.g., by the processor 126 of the ultrasound system 112) to determine the difference between the current position of the imaging plane and the position of the target plane and to generate instructions to adjust the position of the imaging plane to the position of the target plane. The coordinate system can be used to determine the position and orientation to change these positions in up to three spatial and three rotational dimensions. Figure 4A The probe 406 is shown aligned along a reference plane, which may be aligned along the long axis of the fiber 434 passing through the anisotropic tissue 405. For clarity, the probe 406 is depicted as being positioned directly on the anisotropic tissue 405, but it should be understood that one or more other tissues of the subject (e.g., fat, skin) may exist between the probe 406 and the region of the anisotropic tissue 405. Similarly, the position tracking system 416 is shown as being positioned on the lower surface of the anisotropic tissue 405, but it should be understood that one or more materials (e.g., other tissues of the subject, the subject's clothing, air, bedding, etc.) may exist between the position tracking system 416 and the anisotropic tissue 405.

[0058] The reference plane, detector 406, position tracking system 416, and target plane can each be associated with a coordinate system. The coordinates can be 3D coordinates, such as xyz coordinates. In other examples, other coordinate systems (e.g., polar coordinates) can be used. The coordinate system can be used to define the position of its respective plane in space. For example, Figure 4A As shown, the reference plane is positioned along the x and y axes of reference coordinate system 442. The positions of the reference plane, probe 406, position tracking system 416, and target plane can be tracked within their respective coordinate systems, and transformations based on the positions of the coordinate systems can be used to determine the positions of these elements relative to each other.

[0059] Position tracking coordinate system 440 (or world coordinate system) may be xyz coordinates represented as x_world, y_world, and z_world. Position tracking coordinate system 440 may be aligned with the position of position tracking system 416, which may have a known position relative to an object (e.g., a predetermined placement in an examination room, or a placement determined intraoperatively using a known registration method (e.g., a rigid point-based registration method). Position tracking coordinate system 440 may thus be used to describe a position relative to position tracking system 416 and, therefore, relative to an object.

[0060] The reference coordinate system 442 may be an xyz coordinate system represented as x_ref, y_ref, and z_ref. As described herein, the reference coordinate system 442 may be aligned with anatomical features of the anisotropic tissue 405 and / or selected by a user. By using a known relationship between the reference coordinate system 442 and the world coordinate system 440, the position of the tissue may be known relative to the position tracking system. Transformation 世界 T ref It may be determined to transform the coordinate information from the reference coordinate system 442 to the world coordinate system 440. Once the transformation is determined, the object may need to remain in a fixed position relative to the position tracking system 416 (eg, by lying still).

[0061] One or more target planes may be defined relative to the reference plane. Each target plane may have a target coordinate system 444. The target coordinate system 444 may be an xyz coordinate system having axes denoted as x_target, y_target, z_target. The transformation ref T 目标 The coordinate information is determined to be transformed from the target coordinate system 444 to the reference coordinate system 442. By linking the target coordinate system to the reference coordinate system 442 (which in turn is linked to the position tracking coordinate system 440), the position of each target plane relative to the position tracking system 416 can be determined.

[0062] The current position of the probe 406 may be expressed in a current coordinate system 446. The current coordinate system 446 may be linked to the position of the probe 406 and may move as the probe 406 moves. The current coordinate system 446 may be an xyz coordinate system having axes denoted as x_current, y_current, and z_current. Figure 4A As shown in , the current coordinate system 446 is aligned with the reference coordinate system (442). Figure 4A As shown by the arrow, the reference coordinate system 442 can be used to 世界 T ref is transformed to the world coordinate system 440. Figure 4B As shown in , the current coordinate system 446 has been rotated by approximately 90° to align with the target coordinate system 444. The transformation between the current coordinate system 446 and the world coordinate system 440 can be achieved by transforming 世界 T 当前 The transformation may be determined by the position tracking system 416.

[0063] The ultrasound system's processor (e.g. Figure 1 The processor 126) can use the transformation between the coordinate systems to generate a direction for positioning the probe 406. The processor can generate a transformation of the current imaging plane position relative to the target plane position according to Formula 1:

[0064] 目标 T当前 =( ref T 目标 ) -1 ( 世界 T ref ) -1 世界 T 当前 Formula 1

[0065] The processor may calculate the position of the current imaging plane to the position of the target plane in real time. As described herein, the processor may generate feedback or instructions to adjust the position of the imaging plane to reduce the difference between the position of the current imaging plane and the position of the target plane. The processor may be based on the transformation 目标 T 当前 The difference between the position of the imaging plane and the position of the target plane is calculated. As described herein, a display (e.g., Figure 1 The display 120 may display feedback (e.g., Figure 1 122).

[0066] A general transformation of Equation 1 can be used to generate specific instructions for adjusting the position of the probe 406. Figures 4A-4B In the example shown, the target plane coordinate system 444 is rotated 90° relative to the reference plane coordinate system 442 about their mutual y-axis y_ref / y_target. In other words, there is an angle of 90° between x_ref and x_target and between z_ref and z_target. In this example, the only position change that the imaging plane needs to undergo is a rotation. The angle β between the current probe position (determined by the current probe coordinate system 446) and the target coordinate system 444 can be determined by:

[0067]

[0068]

[0069] in, T is the transpose operator, 目标 R 当前 is the transformation matrix 目标 T 当前 The rotation component of is the transformed column unit vector along x_current to plane XZ 目标 The projection on the plane XZ 目标 is a plane defined along axes x_target and z_target of target coordinate system 444; is normalized. The angle β can be calculated in real time and can be displayed with one or more visual indicators (e.g., Figure 1The visual indicator 122 of the target plane is presented to the user. Although the position of the target plane and the current imaging plane can only change by an angle β in this example, other angles and / or other position elements can be calculated based on the transformation. In some examples, 3 rotation angles and 3 position vectors can be calculated to provide 3D / 6DOF position information.

[0070] Figures 5A-5C Graphical user interface (GUI) elements 500, 505, and 510 including visual indicators are depicted according to some examples of the present disclosure. The visual indicators can be generated in real time and can provide guidance to the operator on how to reposition or manipulate the probe to acquire one or more target image planes. In some examples, the visual indicators can include instructions for repositioning the probe so that the imaging plane of the probe is aligned with the target image plane so that an image of an object on the target image plane can be acquired. The visual indicators can also provide feedback on the current position of the imaging plane relative to the reference plane and one or more target planes. Figures 5A-5C Visual indicators 522a-c, reference indicator 548a, target indicators 550a-c, current indicators 552a-c, and organization indicator 554a are shown. The visual indicators in the examples herein may be used to implement any visual indicator of the present disclosure (e.g., Figure 1 122). Figures 5A-5C The components shown and their arrangement are illustrative only, and other variations, including removing components, combining components, rearranging components, and substituting components, are contemplated.

[0071] Figures 5A-5C Depicted are example visual indicators 522a - c that may be used to guide alignment of a current imaging plane with a target plane. Figure 5A and 5B Two visual indicators 522a, b are depicted when the current imaging plane is in a first position and a second position, respectively. Figure 5B The visual indicators are labeled 522a' and 522b' to indicate the locations of the changes. Figure 5CDepicted is a visual indicator 522c according to another example. Any of the visual indicators 522a-c may be provided on a display (e.g., as GUI elements 500, 505, 510 of a graphical user interface). Any of the visual indicators 522a-c may include a reference indicator 548 configured to depict the position of a reference plane, a target indicator 550 configured to depict the position of a target plane, a current indicator 552 configured to depict the current position of the imaging plane, a tissue indicator 554 configured to depict properties of the tissue (e.g., fiber orientation of the tissue), or a combination thereof. Notably, in some examples and as further described below, the current indicator may be configured to be dynamically updated (e.g., when the operation moves the probe) such that it provides a visual indication of the relative angle between the target image plane and the current image plane (i.e., the image plane of the probe at the current position) at any given time, or some quantitative or qualitative measure of how close the current image plane is to the target image plane.

[0072] In the example shown, the visual indicators 522a include a reference indicator 548a in the form of a rectangular bar, a target indicator 550a, and a current indicator 552a, which schematically represent an imaging array or probe (e.g., Figure 1 In some examples, the rectangular bar for each different indicator may be represented slightly differently. For example, the indicator (in this case, the rectangular bar) associated with the reference image plane may be displayed in one color, while the indicators associated with the other image planes may be represented in a different color, or in some cases, one or more may appear as an outline while the others may be filled. In the specific illustrated example, the rectangular bar for the target indicator 550a is displayed as an outline, while the rectangular bar for the current indicator 552a is displayed as a filled bar. When the operator positions the probe to align with the target plane (such as Figure 5B ), the filled bar is aligned with and fills the outline of the target indicator. In other examples, the indicator can be configured differently than the other indicators in one or two dimensions, for example, the target or current indicator can be longer. In other examples, the indicators can be distinguished differently from each other, such as being different colors and / or having different borders (e.g., solid borders, dashed borders, dotted borders, etc.). In some examples, a legend can be provided to help distinguish the indicators.

[0073] In this example, the indicator is overlaid on the tissue indicator 554, which may include one or more lines to represent the direction of the fibers of the anisotropic tissue (e.g., fibers 334 of FIG. 3). In this example, the visual indicator 522a depicts a simulated top view (e.g., looking down toward the axis of the probe toward the tissue), wherein the target plane is rotated about 90° relative to the reference plane. The visual indicator 522a thus shows that the target indicator 550a is rotated about 90° with respect to the reference indicator 548a. The system can update the current indicator 552a in real time to depict the current position of the imaging plane.

[0074] The visual indicator 522b shows the current position of the probe represented by the current indicator 552b along the target indicator 550b (which is a numerical scale). The target indicator 550b can be a normalized value or score (e.g., between 0-100) indicating how close the current position of the imaging plane is to the current target plane. Thus, one end of the target indicator 550b can represent a perfect alignment of the current plane with the target plane (e.g., a score of 100), while the other end of the scale (e.g., a score of 0) can represent a complete misalignment of the current plane with the target plane (e.g., orthogonal to the target plane). The current indicator 552b can be provided in the form of an arrow or a slider that moves along the target indicator 550b to represent the current position of the imaging plane relative to the target plane.

[0075] The visual indicator 552c shows a current indicator 552c and a target indicator 550c, both of which are renderings of the 3D shape of the probe. The 3D rendering can be a realistic depiction of the probe or it can be stylized. The current indicator 552c can be a solid rendering representing the current position of the probe. The target indicator 550c can be a semi-transparent (or wireframe) model of the probe position so that when the probe is in that position, the imaging plane generated by the probe is aligned with the target plane. The target indicator 550c can be presented in a different color than the current indicator 552c, and the color can change in response to the changing position of the probe. An arrow representing the recommended movement of the probe (e.g., tilt) to match the target indicator 550c can be displayed.

[0076] Instructions and feedback from the visual indicators 522a-c can be used to adjust the position of the probe until the current indicator 552a-c matches the target indicator 550a-c. The system can provide feedback (e.g., a change in color, tone, or displayed message) to indicate that the current imaging plane is aligned with the target plane (or within an acceptable tolerance of alignment). The system can prompt the user to record a shear wave elastography image at this point and / or the system can automatically record a shear wave elastography image. The visual indicators 522a-c can then be updated to display the new target plane along with the target indicator 550a-c, or can indicate that the measurement sequence has been completed.

[0077] As an example, Figure 5A Two visual indicators 522a and 522b are shown, each presenting the current position of the same probe. In both cases, the current indicators 552a, 552b indicate that the probe is not currently aligned with the target probe. Visual indicator 522a shows a simplified 2D representation of the probe position (as if looking down from the top), and shows that the current indicator 552a is not aligned with the target indicator 550a. Visual indicator 522b shows the current indicator 552b along the target indicator 550b, which is a numerical axis below a maximum value (e.g., 100) that represents alignment with the target plane. Figure 5B The same two visual indicators 522a' and 522b' are shown, which reflect the new position of the probe with the imaging plane aligned with the target plane. In the case of visual indicator 522a', the current indicator 552a' is now within the target indicator 550a, which is an outline indicating the position of the probe with the imaging plane aligned with the target plane. In the case of visual indicator 522b', the current indicator 552b' has increased along the target indicator 550b (digital scale) until it reaches or approaches a maximum value. In other examples, non-visual cues can be provided to the guidance in addition or alternatively. For example, in addition to the visual indicator, when the system determines that the probe is positioned so that the imaging plane of the probe is fully aligned with the target plane (e.g., corresponding to the position of the current indicator 552b located anywhere between 90-100), the system can be configured to provide a tactile or auditory indicator (e.g., a beep or other sound).

[0078] Figure 6A-6B is an example display including a shear wave elastography image according to some embodiments of the present disclosure. The image may be presented to a user on a display (e.g., Figure 1 The information may be displayed on display 120 of the system) and / or may be stored in a memory of the system (e.g., memory 130) for later analysis. Figure 6A-6B Images 624, 624' and position indicators 654, 654' are depicted. In certain embodiments, images 624, 624' may be Figure 1 Implementation of image 124. Figure 6A-6B The components shown in are illustrative only, and other variations, including removing components, combining components, rearranging components, and replacing components, are contemplated.

[0079] Fig. 6A and 6B It shows that it can be presented on a display (such as Figure 1The images 624, 624' may be presented to the user in real time and / or may be saved (such as in a Figure 1 The image plane position information may be calculated for each image 624, 624' and saved with the image 624, 624'. The image 624, 624' may include a position indicator 654, 654' indicating the position of the imaging plane shown in the image 624, 624' relative to the reference plane. Fig. 6A The image 624 is shown aligned with the reference plane, as indicated by the position indicator 654, while Figure 6B An image 624' is shown aligned orthogonally to the reference plane, as indicated by a position indicator 654'. The position indicator 654, 654' may be superimposed on the image 624, 624'. The position indicator 654, 654' may be text, or may be some other representation of the position, such as a graphical display or a normalized score.

[0080] Figure 7A-7B is a block diagram of a coordinate system defined by probe placement and orientation of anisotropic tissue according to some embodiments of the present disclosure. When determining the position of the imaging plane, the orientation of the tissue can be considered to account for changes in the direction of the tissue (e.g., changes in the orientation of the fibers of the tissue). Figure 7A-7B Depicted are anisotropic tissue 705, probe 706, fibers 734, position tracking system 716, position (or world) coordinate system 740, reference coordinate system 742, target coordinate system 744, current coordinate system 746, and tissue coordinate system 743 aligned with muscle fibers. In certain embodiments, probe 706 may be Figure 1 An embodiment of the probe 106. Figure 7A-7B The components shown in are illustrative only, and other variations, including removing components, combining components, rearranging components, and replacing components, are contemplated.

[0081] Figure 7A-7B The coordinate system can be roughly similar to Figures 4A-4B , but Figure 7A-7B A tissue coordinate system 743 is introduced to describe the position of the fibers of the anisotropic tissue 705. The tissue coordinate system 743 may be an xyz coordinate system including x_tissue, y_tissue, and z_tissue. Figure 7A-7BIn the example shown, the tissue is muscle tissue, so the tissue coordinate system 743 is a muscle coordinate system including x_muscle, y_muscle and z_muscle. Although muscle is specified here, it should be understood that the tissue coordinate system can be aligned to any type of anisotropic tissue. Anisotropic tissue 705 can have elements that are not aligned along any of the world coordinate system 740, the reference coordinate system 742 and / or the target coordinate system 744, such as fiber 734. The orientation of fiber 734 can change along the length of the anisotropic tissue 705. Therefore, in this case, the tissue coordinate system 743 aligned with the fiber 734 can also change along the length of the tissue 705. The tissue coordinate system 743 can be defined by the user. The tissue coordinate system 743 can be automatically generated by extracting the orientation of the fiber 734 from the image, for example, by Hough transform, segmentation and parameterization of the fiber 734 and / or backscattered acoustic properties. The target plane can be selected to align with the fiber 734. When a separate tissue coordinate system 743 exists, Formula 1 defining the transformation between target coordinates and current coordinates may be modified to Formula 4:

[0082] 目标 T 当前 = 目标 T 肌肉 肌肉 T ref ( 世界 T ref ) -1 世界 T 当前 Formula 4 in, 世界 T 当前 is the transformation between the current coordinate system 746 and the world coordinate system 740, and 目标 T 肌肉 is the transformation between the organization coordinate system 743 and the target coordinate system 744. Similar to the instructions of equations 2 and 3, further calculations can be performed to generate specific instructions such as specific angles or position changes between elements of the target coordinate system 744 and the current coordinate system 746.

[0083] Fig. 7A and 7B The probe 706 is shown rotated to align with the target plane. In the example shown, the target plane is aligned with the fibers 734 of the anisotropic tissue 705. Fig. 7A The probe 706 is shown aligned with a reference plane (eg, the current coordinate system 746 and the reference coordinate system 742 are aligned). In this example, the probe 706 may need to undergo two rotations (about y_ref and about z_ref) to align the current imaging plane with the target plane. Figure 7BThe probe 706 is shown aligned with the target coordinate system 744. The transformation calculated in Equation 4 can be used to generate instructions for changes in the desired position of the probe 706 in real time and allow the target plane to be selected at different points along the tissue with different orientations of the fibers 734.

[0084] Figure 8 800 is a flowchart depicting multi-angle shear wave imaging according to certain embodiments of the present disclosure. Example method 800 illustrates steps that may be utilized by the systems and / or devices described herein in any order. The method may be performed by, for example, Figure 1 In some embodiments, the method 800 may be implemented in the instructions 132 of the system 112 and executed by the processor 126.

[0085] In the illustrated embodiment, method 800 begins at block 810 by "determining a position of a probe relative to an imaging plane of anisotropic tissue based at least in part on position tracking data generated based on sensor data received from a position sensor coupled to the probe."

[0086] At block 820, the method involves "defining at least one target plane."

[0087] At block 830, the method includes "determining a difference between a position of an imaging plane and a position of at least one target plane."

[0088] At block 840, the method includes "providing a visual indicator of the determined difference on a display, and dynamically updating the visual indicator in response to a change in the position of the imaging plane."

[0089] At block 850, the method involves "generating, using the transducer, at least one shear wave image of a target plane."

[0090] Method 800 may also include generating instructions to adjust the position of the imaging plane. Figure 1 The instructions may be provided to the user by a visual indicator 122 of the form. The user may adjust the position of the probe in response to the instructions and may receive additional feedback as the adjustments continue. The instructions may also be used to automatically adjust the position of the imaging plane, for example by changing the position of the probe and / or by changing the position of the imaging plane relative to the probe. The position of the probe may be controlled, for example, by a controller such as Figure 1 The position of the imaging plane relative to the probe can be changed by, for example, moving the transducer within the plane or using beam steering.

[0091] The steps of method 800 may be repeated. For example, blocks 820-850 may be repeated for multiple target planes at different locations around the tissue. The steps of method 800 may be run continuously, such as block 810, or may be performed in response to an input, such as block 850, which may be triggered, for example, by a user, or may be triggered when the system detects that a certain condition is met (e.g., the measured difference between the imaging plane and the target plane falls below a threshold).

[0092] In various embodiments where programmable devices such as computer-based systems or programmable logic are used to implement the components, systems and / or methods, it should be understood that the above systems and methods can be implemented using any of a variety of known or later developed programming languages, such as "C", "C++", "FORTRAN", "Pascal", "VHDL", etc. Thus, various storage media, such as magnetic computer disks, optical disks, electronic memory, etc., can be prepared, which can contain information that can instruct devices such as computers to implement the above systems and / or methods. Once the information and programs contained on the storage medium are accessible to the appropriate device, the storage medium can provide the information and programs to the device, thereby enabling the device to perform the functions of the systems and / or methods described herein. For example, if a computer disk containing appropriate materials (such as source files, object files, executable files, etc.) is provided to a computer, the computer can receive the information, configure itself appropriately and perform the functions of the various systems and methods depicted in the above diagrams and flow charts to implement various functions. That is, the computer can receive various portions of information related to different elements of the above systems and / or methods from the disk, implement individual systems and / or methods, and coordinate the functions of the individual systems and / or methods described above.

[0093] In view of the present disclosure, it should be noted that the various methods and devices described herein can be implemented in hardware, software, and firmware. In addition, various methods and parameters are included only as examples without any limiting meaning. In view of the present disclosure, those of ordinary skill in the art can implement this teaching while determining their own technology and the required equipment that affects these technologies, while still within the scope of the present disclosure. The functions of one or more processors described herein can be combined into a smaller number or a single processing unit (e.g., CPU), and can be implemented using a dedicated integrated circuit (ASIC) or a general-purpose processing circuit that is programmed to perform the functions described herein in response to executable instructions.

[0094] Although the present system may have been described with particular reference to an ultrasound imaging system, it is also contemplated that the present system may be extended to other medical imaging systems that obtain one or more images in a systematic manner. Thus, the present system may be used to obtain and / or record image information related to the kidney, testicles, breast, ovary, uterus, thyroid, liver, lung, musculoskeletal, spleen, heart, arterial and vascular systems, as well as other imaging applications related to ultrasound-guided interventions, but not limited thereto. In addition, the present system may also include one or more programs that can be used with conventional imaging systems so that they can provide the features and advantages of the present system. Upon studying the present disclosure, certain other advantages and features of the present disclosure may be apparent to those skilled in the art, or may be experienced by those who employ the novel systems and methods of the present disclosure. Another advantage of the present system and method may be that a traditional medical imaging system may be easily upgraded to incorporate the features and advantages of the present system, device and method.

[0095] Of course, it should be understood that, according to the present systems, devices and methods, any of the examples, embodiments or processes described herein may be combined with one or more other examples, embodiments and / or processes, or be separated and / or performed in discrete devices or device portions.

[0096] Ultimately, the above discussion is intended to be merely illustrative of the system of the present invention and should not be construed as limiting the appended claims to any particular embodiment or group of embodiments. Thus, although the present system has been described in detail with reference to exemplary embodiments, it should also be appreciated that numerous variations and alternative embodiments may be devised by those skilled in the art without departing from the broader spirit and scope of the present system as set forth in the claims. Accordingly, the specification and drawings should be regarded in an illustrative manner and are not intended to limit the scope of the appended claims.

Claims

1. An ultrasonic imaging system for shear wave imaging, comprising: a probe configured to acquire ultrasound echo signals to generate a shear wave image of anisotropic tissue of a subject, wherein the probe is configured to be coupled to a position tracking system to track a position of the probe relative to the subject; a processor in communication with the probe and configured to receive position tracking data from the position tracking system, wherein the processor is further configured to: defining at least one target plane in the anisotropic tissue at an angle relative to a reference plane of the anisotropic tissue; determining a difference between a first position of an imaging plane of the probe at a position indicated by the position tracking data and a second position of the at least one target plane; and A visual indicator of the difference is provided on a display of the ultrasound system, wherein the processor is configured to dynamically update the visual indicator in response to changes in the position of the imaging plane relative to the target plane.

2. The ultrasound imaging system according to claim 1, wherein: The probe includes at least one sensor configured to receive information from the position tracking system to dynamically determine a position of the probe.

3. The ultrasound imaging system according to claim 2, wherein: The position tracking system includes an electromagnetic field generator, and the at least one sensor includes at least one electromagnetic sensor attached to the probe.

4. The ultrasound imaging system according to claim 3, wherein: The at least one electromagnetic sensor is embedded in the probe.

5. The ultrasound imaging system according to claim 1, wherein: The processor is further configured to cause at least one shear wave image to be automatically generated when the difference between the first position and the second position is below a threshold.

6. The ultrasound imaging system according to claim 1, wherein: The processor is configured to receive an indication of the reference plane in response to a user input.

7. The ultrasound imaging system of claim 6, further comprising a reference plane selector, and wherein: The processor is further configured to set the reference plane as a current imaging plane of the probe in response to activation of the reference plane selector.

8. The ultrasound imaging system according to claim 1, wherein: The processor is configured to determine the reference plane based on the orientation of fibers of the anisotropic tissue.

9. The ultrasound imaging system according to claim 8, wherein: The processor is configured to position the reference plane such that it is aligned with the direction of the fibers of the anisotropic tissue.

10. The ultrasound imaging system according to claim 8, wherein: The anisotropic tissue is selected from musculoskeletal tissue, myocardial tissue, vascular wall tissue, and thyroid tissue, and wherein the processor is configured to estimate the orientation of fibers of the musculoskeletal tissue, myocardial tissue, vascular wall tissue, or thyroid tissue.

11. The ultrasound imaging system according to claim 10, wherein: The processor is also configured to estimate the orientation of the fibers based at least in part on the 3D image of the anisotropic tissue.

12. The ultrasound imaging system according to claim 1, wherein: The processor is further configured to define the at least one target plane at a predetermined angle relative to the reference plane.

13. The ultrasound imaging system according to claim 12, wherein: The processor is configured to define a plurality of target planes at predetermined angular intervals relative to the reference plane.

14. The ultrasound imaging system according to claim 1, wherein: The processor is further configured to generate instructions for adjusting a position of the probe, wherein the instructions are configured to reduce a difference between the first position and the second position.

15. The ultrasound imaging system according to claim 14, wherein: The processor is further configured to control an actuator based on the instructions to automatically adjust the position of the probe.

16. The ultrasound imaging system according to claim 14, wherein: The visual indicators include a current plane indicator and a target plane indicator, wherein the current plane indicator is dynamically adjusted by the processor in response to changes in the position of the probe relative to the target plane.

17. The ultrasound imaging system according to claim 16, wherein: The current plane indicator is a visual representation of the current imaging plane of the probe.

18. The ultrasound imaging system according to claim 15, wherein: The target plane indicator is a visual representation of an imaging plane corresponding to the target plane.

19. The ultrasound imaging system according to claim 13, wherein: The visual indicator includes a numerical scale having a dynamic component configured to move along the scale in response to a change in the determined difference.

20. The ultrasound imaging system of claim 1, wherein: The position tracking system is configured to determine a spatial position of the probe and a rotation of the probe relative to the reference plane.

21. An ultrasonic imaging method for shear wave imaging, the method comprising: receiving position tracking data from a position tracking system coupled to a probe configured to acquire ultrasound echo signals to generate a shear wave image of anisotropic tissue of a subject; defining at least one target plane in the anisotropic tissue at an angle relative to a reference plane of the anisotropic tissue; determining a difference between a first position of an imaging plane of the probe at a position indicated by the position tracking data and a second position of the at least one target plane; and A visual indicator of the difference is provided on a display of the ultrasound system, and the visual indicator is dynamically updated in response to changes in the position of the imaging plane relative to the target plane.

22. The method of claim 21, further comprising generating instructions for adjusting the position of the imaging plane, wherein: The instructions are configured to reduce the determined difference.

23. The method of claim 22, further comprising adjusting a position of the imaging plane based on the generated instructions.

24. The method according to claim 23, wherein: The adjusting the position of the imaging plane includes: adjusting the position of the probe, adjusting at least one angular orientation of the probe, or a combination thereof.

25. The method of claim 22, further comprising sending the generated instructions to an actuator configured to control the position of the imaging plane.

26. The method of claim 21, further comprising defining a transformation between an orientation of the anisotropic tissue and a position of the imaging plane.

27. The method of claim 26, further comprising adjusting the position of the imaging plane to align with the orientation of the anisotropic tissue.

28. The method of claim 21, further comprising generating at least one shear wave image of the target plane using the probe.

29. The method of claim 28, further comprising displaying the determined position of the imaging plane on at least one shear wave image generated at the determined position.

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