Systems and methods for vascular imaging

Abstract

Disclosed are systems and methods for constructing and displaying multi-level vascular imaging of the vasculature from large vessels to small vessels and microvessels using a combination of different resolution contrast-enhanced ultrasound flow imaging modalities. While one or more resolution flow imaging modalities can be employed for imaging large to small vessels of the vascular tree within a large region of interest, a high-resolution modality, such as super-resolution imaging, constructed to depict microvascular morphology and directional microcirculation is provided within one or more small ROIs placed in selected locations within the larger ROI.

Description

Technical Field

[0001] The present invention relates to contrast-enhanced imaging. More particularly, the present invention relates to contrast-enhanced ultrasound for vascular imaging. Background Art

[0002] In contrast-enhanced imaging, a contrast agent is provided to the area or volume to be imaged so as to provide a higher signal intensity from the area or volume, or to selectively enhance the signal from an area or volume with a high contrast concentration. For example, in contrast-enhanced ultrasound (CEUS), microbubbles can be injected into the bloodstream of an object, and an ultrasound image of the object's vascular system can be acquired. Without microbubbles, blood vessels can only provide little or no signal. In contrast accumulation imaging (CAI), multiple contrast-enhanced images (e.g., multiple image frames) are acquired and combined and / or normalized to form a final image, which can be used to map the progression of the contrast agent and enhance vascular topology and significance. Time-accumulated imaging of CEUS has been commercialized and widely used for vascular visualization. However, due to the large size of the point spread function (PSF) in contrast mode, CEUS has limited spatial resolution. PSF is a measure of the blur or diffusion of a point source by the imaging system. Due to combining multiple image frames to form the final image, CEUS may also have strong residual clutter artifacts and be susceptible to patient-induced motion.

[0003] Super-resolution imaging (SRI) is a CEUS technique that potentially enables improved diagnosis of vascular diseases and malignancies by comprehensively providing details previously impossible using conventional methods for morphological microvascular images as well as functional microcirculatory maps. In conventional SRI techniques, each super-resolution image is obtained in two steps: (1) locating the center of each isolable microbubble in the image, and then (2) accumulating these centers over thousands of images. The position of each microbubble is obtained by taking the local maximum of the intensity distribution of each microbubble. This means that the center of each microbubble can be seen and represented as a single pixel. The accumulation of the central positions of the microbubbles is a probability density map of the microbubbles, which is a super-resolution image of the microvasculature.

[0004] However, the time scale of acquisition is challenging when imaging large areas or pathologies where bubble inflow dynamics are particularly important (e.g., visualizing rapid wash-in). Compared to conventional contrast ultrasound scanning, SRI typically requires tens or hundreds of thousands of individual contrast imaging frames corresponding to a combination of very high imaging frame rates (typically >500 Hz) and very long acquisition times (e.g., several minutes). Summary of the Invention

[0005] Systems and methods for multi-level resolution vascular imaging methods are disclosed. The systems and methods may include (1) employing one or more contrast imaging modes with conventional and enhanced spatial resolution to display the vascular tree from large vessels to small vessels within a large ROI, and (2) SRI modes are created to depict microvascular morphology and functional microcirculation within one or more small ROIs placed in selected locations within the large ROI. Advantages of multi-level CEUS imaging according to the principles of the present disclosure may include (1) adequate display of vascular distribution at different levels, from large vessels to small vessels to anatomically and functionally detailed microvascular circulation; (2) shortened processing time for SRI reconstruction and thus facilitated display of microstructure; and (3) allowing effective correction of local physiological motion that may be critical in SRI.

[0006] According to at least one example disclosed herein, an ultrasound imaging system may include: an ultrasound probe for transmitting and receiving ultrasound signals for a plurality of ultrasound images, wherein the plurality of ultrasound images are contrast-enhanced ultrasound images; a display configured to display at least one of the plurality of ultrasound images; a user interface configured to receive user input via at least one user control, wherein the user input indicates a first region of interest (ROI) within the at least one of the plurality of ultrasound images, wherein the first ROI includes less than an entirety of the at least one of the plurality of ultrasound images; and at least one processor in communication with the user interface, the at least one processor configured to: process at least some of the plurality of ultrasound images using a first processing technique; and process at least some of the plurality of ultrasound images in the first ROI using a second processing technique, wherein the second processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique, wherein the display is further configured to display the at least some of the plurality of ultrasound images processed using the first processing technique and the at least some of the plurality of ultrasound images processed using the second processing technique.

[0007] According to at least one example disclosed herein, a method may include receiving a plurality of ultrasound images, wherein the plurality of ultrasound images are contrast-enhanced ultrasound images; displaying at least one ultrasound image of the plurality of ultrasound images; receiving an indication of a region of interest (ROI) within the at least one ultrasound image of the plurality of ultrasound images, wherein the ROI includes an entirety that is smaller than the at least one ultrasound image of the plurality of ultrasound images; processing a first set of the plurality of ultrasound images using a first processing technique; and processing a second set of the plurality of ultrasound images in the ROI using a second processing technique, wherein the second processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique.

[0008] According to at least one example disclosed herein, a non-transitory computer-readable medium comprising instructions that, when executed, may cause an ultrasound imaging system to: receive a plurality of ultrasound images, wherein the ultrasound images are contrast-enhanced ultrasound images; display at least one ultrasound image of the plurality of ultrasound images; receive an indication of a region of interest (ROI) within the at least one ultrasound image of the plurality of ultrasound images, wherein the first ROI includes an entirety that is smaller than the at least one ultrasound image of the plurality of ultrasound images; process a first set of the plurality of ultrasound images using a first processing technique; and process a second set of the plurality of ultrasound images in the ROI using a second processing technique, wherein the second processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a block diagram of an ultrasound imaging system arranged according to some examples of the present disclosure.

[0010] Figure 2 is a block diagram illustrating an example processor according to some examples of the present disclosure.

[0011] Figure 3 is an illustration of an example image of a dual-level resolution CEUS system in accordance with the principles of the present disclosure.

[0012] Figure 4 is an illustration of an example image of a multi-level resolution CEUS system in accordance with the principles of the present disclosure.

[0013] Figure 5 is a flow chart of a method according to the principles of the present disclosure. DETAILED DESCRIPTION

[0014] The following descriptions of specific illustrative examples are merely exemplary in nature and are in no way intended to limit the present disclosure or its application or use. In the following detailed description of examples of the present systems and methods, reference is made to the accompanying drawings, which form a part thereof and in which specific examples of the described systems and methods are shown by way of illustration. These examples are described in sufficient detail to enable those skilled in the art to practice the presently disclosed systems and methods, and it is understood that other examples may be utilized and that structural and logical changes may be made without departing from the spirit and scope of the present disclosure. In addition, for the sake of clarity, detailed descriptions of certain features will not be discussed when they will be apparent to those skilled in the art so as not to obscure the description of the present disclosure. Therefore, the following detailed description should not be viewed in a restrictive sense, and the scope of the present systems and methods is limited solely by the claims.

[0015] Chronic kidney disease, one of the major complications of diabetes, leads to significant changes in the early renal microvasculature and perfusion. Although contrast-enhanced ultrasound (CEUS) is sensitive to changes in microvascular perfusion, early changes in microstructure and microcirculation are difficult to image using conventional ultrasound due to poor spatial resolution. This also applies to the early detection of chronic peripheral vascular disease and the early diagnosis of malignant tumors.

[0016] CEUS has been used clinically to image organ / tumor vascularity and assess tissue perfusion. However, its inherently low spatial resolution prevents CEUS from being appropriately adjusted for different clinical needs. Due to the lack of vascular clarity in small vessels and capillaries in conventional CEUS, super-resolution imaging (SRI) has been developed in recent years to improve the spatial resolution of ultrasound imaging by locating contrast microbubbles flowing in the microvasculature. However, as previously discussed, SRI inherently has both low motion tolerance and low temporal resolution due to its two basic requirements of precise microbubble localization and long frame accumulation.

[0017] Although SRI can image very fine structures and provide functional information down to the capillary level, it may be impractical to construct and display super-resolution images of large areas (such as large portions of entire organs or tumors). Furthermore, imaging and displaying large vessels using SRI may be ineffective because existing conventional high temporal resolution imaging modalities are sufficient for large vessels. Therefore, multi-level contrast imaging methods as disclosed herein can provide more effective and / or optimal views of various levels of a particular vasculature. A multimodal ultrasound vascular imaging system according to the principles of the present disclosure may be able to provide high temporal resolution for large vessels (e.g., CEUS) and high spatial resolution for microvascular imaging (e.g., SRI).

[0018] The present disclosure relates to systems and methods for multi-level vascular imaging of the construction and display of vasculature from large vessels to small vessels and microvessels using a combination of different resolution CEUS flow imaging modalities. While one or more resolution flow imaging modes can be used to image large to small vessels of a vascular tree within a large region of interest (ROI), the SRI mode is constructed to depict microvascular morphology and directional microcirculation within one or more small ROIs placed in selected locations within a larger ROI. Examples of flow imaging modes include, but are not limited to, CEUS, color Doppler, color power angiography (CPA), microflow imaging (MFI), CEUS-MFI, microvascular imaging (MVI), and high-definition MVI (HD-MVI). In general, different modes can be utilized to image different vascular levels, from large vessels to small vessels to capillaries.

[0019] Figure 1 A block diagram of an ultrasound imaging system 200 constructed according to the principles of the present disclosure is shown. The ultrasound imaging system 100 according to the present disclosure may include a transducer array 114, which may be included in an ultrasound probe 112, such as an external probe or an internal probe, such as an intravascular ultrasound (IVUS) catheter probe. In other examples, the transducer array 114 may be in the form of a flexible array that is configured to be conformally applied to the surface of an object to be imaged (e.g., a patient). The transducer array 114 is configured to transmit ultrasound signals (e.g., beams, waves) and receive echoes (e.g., received ultrasound signals) in response to the transmitted ultrasound signals. A variety of transducer arrays may be used, such as linear arrays, curved arrays, or phased arrays. The transducer array 114 may, for example, include a two-dimensional array of transducer elements (as shown) that can be scanned in both elevation and azimuth dimensions for 2D and / or 3D imaging. As is known, the axial direction is the direction perpendicular to the array plane (the axial fan-out in the case of a curved array), the azimuthal direction is usually defined by the longitudinal extent of the array, and the elevation direction is transverse to the azimuthal direction.

[0020] In some examples, the transducer array 114 can be coupled to a microbeamformer 116, which can be located in the ultrasound probe 112 and which can control the transmission and reception of signals by the transducer elements in the array 114. In some examples, the microbeamformer 116 can control the transmission and reception of signals by the active elements in the array 114 (e.g., an active subset of the elements of the array that define an active aperture at any given time).

[0021] In some examples, the microbeamformer 116 can be coupled, for example, via a probe cable or wirelessly, to a transmit / receive (T / R) switch 118, which switches between transmit and receive and protects the main beamformer 122 from high-energy transmit signals. In some examples, such as in portable ultrasound systems, the T / R switch 118 and other elements of the system can be included in the ultrasound probe 112 rather than in the ultrasound system base, which can house the image processing electronics. The ultrasound system base typically includes software and hardware components, including circuitry for signal processing and image data generation, as well as executable instructions for providing a user interface.

[0022] The transmission of ultrasound signals from the transducer array 114 under the control of the microbeamformer 116 is directed by a transmit controller 120, which can be coupled to the T / R switch 118 and the main beamformer 122. The transmit controller 120 can control the direction in which the beam is steered. The beam can be steered straight ahead from the transducer array 114 (orthogonal to the transducer array 114) or at a different angle for a wider field of view. The transmit controller 120 can also be coupled to a user interface 124 and receive input based on user manipulation of user controls. The user interface 124 can include one or more input devices, such as a control panel 152, which can include one or more mechanical controls (e.g., buttons, encoders, etc.), touch-sensitive controls (e.g., a touchpad, touch screen, or the like), and / or other known input devices.

[0023] In some examples, the partially beamformed signal generated by the microbeamformer 116 can be coupled to the beamformer 122, where the partially beamformed signals from the individual patches of transducer elements can be combined into a fully beamformed signal. In some examples, the microbeamformer 116 is omitted, and the transducer array 114 is under the control of the beamformer 122, which performs all beamforming of the signal. In examples with and without the microbeamformer 116, the beamformed signal from the beamformer 122 is coupled to the processing circuit 150, which can include one or more processors (e.g., a signal processor 126, a B-mode processor 128, a Doppler processor 160, and one or more image generation and processing components 168) configured to generate an ultrasound image based on the beamformed signal (i.e., the beamformed RF data).

[0024] The signal processor 126 can be configured to process the received beamforming RF data in various ways, such as bandpass filtering, decimation, I and Q component separation, and harmonic signal separation. The processor 126 can also perform additional signal enhancements, such as ripple reduction, signal compounding, and electronic noise cancellation. The processed signals (also referred to as I and Q components or IQ signals) can be coupled to additional downstream signal processing circuits for image generation. The IQ signals can be coupled to multiple signal paths within the system, each of which can be associated with a specific arrangement of signal processing components suitable for generating different types of image data (e.g., B-mode image data, Doppler image data). For example, the system can include a B-mode signal path 158 that couples a signal from the signal processor 126 to the B-mode processor 128 to generate B-mode image data.

[0025] B mode processor 128 can adopt amplitude detection to image the structure in the body.B mode processor 128 can generate the signal for tissue image and / or angiographic image.The signal produced by B mode processor 128 can be coupled to scan converter 130 and / or multi-plane reformatter 132.Scan converter 130 can be configured to arrange echo signal according to the spatial relationship that echo signal is received in desired image format.For example, scan converter 130 can arrange echo signal into two-dimensional sector-shaped format, or three-dimensional (3D) format of cone or other shape.In another example of the present disclosure, scan converter 130 can arrange echo signal into contrast-enhanced image and tissue image side by side.As further explained below, in some examples, image processor 136 performs microbubble identification, positioning and accumulation.

[0026] The multiplanar reformatter 132 can convert echoes received from points in a common plane in a volumetric region of the body into an ultrasound image (e.g., a B-mode image) of that plane, for example, as described in U.S. Pat. No. 6,443,896 (Detmer). In some examples, the scan converter 130 and the multiplanar reformatter 132 can be implemented as one or more processors.

[0027] The volume renderer 134 can generate an image (also referred to as a projection, rendering, or rendering) of the 3D data set as viewed from a given reference point, for example, as described in U.S. Pat. No. 6,530,885 (Entrekin et al.). In some examples, the volume renderer 134 can be implemented as one or more processors. The volume renderer 134 can generate renderings, such as positive rendering or negative rendering, by any known or future known technique, such as surface rendering and maximum intensity rendering.

[0028] In some examples, the system may include a Doppler signal path 162 that couples the output from the signal processor 126 to a Doppler processor 160. The Doppler processor 160 may be configured to estimate the Doppler frequency shift and generate Doppler image data. The Doppler image data may include color data, which is then overlaid with B-mode (i.e., grayscale) image data for display. The Doppler processor 160 may be configured to filter out unwanted signals (i.e., noise or clutter associated with non-moving tissue), for example, using a wall filter. The Doppler processor 160 may also be configured to estimate velocity and power according to known techniques. For example, the Doppler processor may include a Doppler estimator such as an autocorrelator, wherein the velocity (Doppler frequency) estimate is based on the parameters of a lag-one autocorrelation function and the Doppler power estimate is based on the amplitude of a lag-zero autocorrelation function. Motion may also be estimated using known phase domain (e.g., parametric frequency estimators such as MUSIC, ESPRIT, etc.) or time domain (e.g., cross-correlation) signal processing techniques. Other estimators related to the temporal or spatial distribution of velocity, such as estimators of acceleration or temporal and / or spatial velocity derivatives, may be used in place of or in addition to the velocity estimator. In some examples, the velocity and power estimates may undergo further thresholding to further reduce noise, as well as segmentation and post-processing, such as padding and smoothing. The velocity and power estimates may then be mapped to a desired range of display colors based on a color map. The color data, also referred to as Doppler image data, may then be coupled to a scan converter 130, where the Doppler image data may be converted to a desired image format and superimposed on a B-mode image of the tissue structure to form a color Doppler or power Doppler image. For example, the Doppler image data may be superimposed on a B-mode image of the tissue structure.

[0029] Outputs from the scan converter 130 , multiplanar reformatter 132 , and / or volume renderer 134 (eg, B-mode images, Doppler images) may be coupled to an image processor 136 for further enhancement, buffering, and temporary storage prior to display on an image display 138 .

[0030] In some examples, the image processor 136 can use different image processing techniques to process the image. For example, the image processor 136 can collect multiple images (e.g., sequential images collected at different time points) and combine them to generate a contrast accumulation image (e.g., MVI). In some examples, the image processor 136 can also analyze individual images to locate one or more microbubbles within the image and find the center of the microbubble and generate one or more SRI images based on SRI image processing technology. Other image processing techniques (e.g., color Doppler, CPA, CEUS-MFI) can also be used. According to the principles of the present disclosure, the image processor 136 can use different image processing techniques to process different areas of the image received from the scan converter 130. For example, contrast accumulation imaging technology can be used to process one or more areas, and SRI technology can be used to process one or more areas.

[0031] Different processing techniques can provide images of a region with different temporal and spatial resolutions. For example, a region processed by an MVI technique can have a lower spatial resolution and a higher spatial resolution than a region processed by an SRI technique. In some examples, the higher spatial resolution can be at least partially the result of a larger number of image frames being combined to generate a final image of the region. In some examples, the higher temporal resolution can be at least partially the result of a smaller number of image frames being combined and / or a faster acquisition rate (e.g., frames per second) of the ultrasound probe.

[0032] In some examples, one or more regions processed using different image processing techniques may at least partially overlap. In some examples, different sets of images may be processed by image processor 136 to process different regions using different processing techniques (e.g., every other image may be used for a first region, and every other image may be used for a second region). In some examples, which regions of an image are processed by image processor 136 using which technique may be based at least in part on a region of interest and / or imaging mode set by a user via user interface 124, as described further below.

[0033] In accordance with the principles of the present disclosure, in some examples, an ultrafast imaging mode with the same pulse sequence can be employed during / after contrast agent injection / infusion. In some examples, the pulse sequence can be based on a control signal provided by the transmit controller 120. In some examples, imaging frames and / or associated RF and / or IQ data can be continuously streamed to a computer-readable medium (e.g., local memory 142) during the entire length of contrast imaging. Data can be provided from the beamformer 122, signal processor 126, B-mode processor 128, Doppler processor 160, and / or scan converter 130. The user interface 124 can allow control over how images or ROIs of a first imaging mode (e.g., CEUS) and one or more additional images or ROIs of a different imaging mode (e.g., SRI) are displayed. In other examples, if it is not possible to continuously save all imaging frames and / or associated RF / IQ data, an interleaving of two pulse sequences can be used, one for the overview mode and the other for super-resolution imaging. In some examples, if system constraints do not allow simultaneous interleaving / acquisition of different imaging modes, then when SRI is selected as the imaging mode, the SRI mode can operate using an implementation similar to PW Doppler, where sparse updates to the reference image utilize plane selection to guide the clinician, while long accumulation / flow operations dominate the system process.

[0034] The graphics processor 140 can generate graphic overlays for display with the images. These graphic overlays can include standard identifying information, such as the patient's name, date and time of the image, imaging parameters, etc. For these purposes, the graphics processor can be configured to receive input from the user interface 124, such as a typed patient name or other annotations. The user interface 124 can also be coupled to the multi-planar reformatter 132 for selecting and controlling the display of multiple multi-planar reformatted (MPR) images.

[0035] The system 100 may include a local memory 142. The local memory 142 may be implemented as any suitable non-transitory computer-readable medium (e.g., a flash drive, a disk drive). The local memory 142 may store data generated by the system 100, including B-mode images, masks, executable instructions, input provided by a user via the user interface 124, or any other information required for the operation of the system 100.

[0036] As previously described, system 100 includes a user interface 124. User interface 124 may include a display 138 and a control panel 152. Display 138 may include a display device implemented using various known display technologies such as LCD, LED, OLED, or plasma display technology. In some examples, display 138 may include multiple displays. Control panel 152 may be configured to receive user input (e.g., examination type, selection of ROI). Control panel 152 may include one or more hard controls (e.g., buttons, knobs, dials, encoders, mice, trackballs, or other). In some examples, control panel 152 may additionally or alternatively include soft controls (e.g., GUI control elements or simply GUI controls) provided on a touch-sensitive display. In some examples, display 138 may be a touch-sensitive display including one or more soft controls of control panel 152.

[0037] In accordance with the principles of the present disclosure, in some examples, a user can set one or more ROIs via the user interface 124. For example, a user can set an ROI on an image provided on the display 138. The ROI can be set by the user by placing a selection box on the image on the display 138 using one or more controls on the control panel 152. The user can determine the imaging mode for the portion of the image within the ROI by providing input via the user interface 124. In some examples, the user can select one or more ROIs and indicate a different imaging mode for each ROI. In some examples, an ROI can be included within another ROI and / or overlap with another ROI. In some examples, the maximum size of the ROI can be based at least in part on the imaging mode selected by the user. For example, the maximum size of an ROI for cumulative CEUS imaging can be larger than the maximum size of an ROI for SRI. In addition to affecting the image displayed on the display 138, the selected imaging mode can affect the processing of the image by the image processor 136 and / or acquisition settings (e.g., the pulse sequence indicated by the transmit controller 120).

[0038] In some examples, Figure 1 The various components shown in FIG. 1 and FIG. 2 can be combined. For example, image processor 136 and graphics processor 140 can be implemented as a single processor. In another example, scan converter 130 and multi-plane reformatter 132 can be implemented as a single processor. In some examples, Figure 1 The various components shown in can be implemented as separate components. For example, the signal processor 126 can be implemented as a separate signal processor for each imaging mode (e.g., B-mode, Doppler). In some examples, Figure 1One or more of the various processors shown in can be implemented by a general-purpose processor and / or microprocessor configured to perform a specified task. In some examples, one or more of the various processors can be implemented as a dedicated circuit. In some examples, one or more of the various processors (e.g., image processor 136) can be implemented using one or more graphics processing units (GPUs).

[0039] Figure 2 is a block diagram illustrating an example processor 200 according to the principles of the present disclosure. The processor 200 may be used to implement one or more of the processors described herein, such as Figure 1 . The processor 200 may be any suitable processor type, including but not limited to a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable array (FPGA) (where the FPGA has been programmed to form a processor), a graphics processing unit (GPU), an application specific circuit (ASIC) (where the ASIC has been designed to form a processor), or a combination thereof.

[0040] Processor 200 may include one or more cores 202. Core 202 may include one or more arithmetic logic units (ALUs) 804. In some examples, core 202 may include a floating point logic unit (FPLU) 206 and / or a digital signal processing unit (DSPU) 208 in addition to or in lieu of ALU 204.

[0041] Processor 200 may include one or more registers 212 communicatively coupled to core 202. Registers 212 may be implemented using dedicated logic gates (e.g., flip-flops) and / or any memory technology. In some examples, registers 212 may be implemented using static memory. Registers may provide data, instructions, and addresses to core 202.

[0042] In some examples, processor 200 can include one or more levels of cache memory 210 communicatively coupled to core 202. Cache memory 210 can provide computer-readable instructions to core 202 for execution. Cache memory 210 can provide data for processing by core 202. In some examples, computer-readable instructions may have been provided to cache memory 210 by local memory (e.g., local memory attached to external bus 216). Cache memory 210 can be implemented with any suitable cache memory type, for example, metal oxide semiconductor (MOS) memory, such as static random access memory (SRAM), dynamic random access memory (DRAM), and / or any other suitable memory technology.

[0043] The processor 200 may include a controller 214 that may control other processors and / or components included in the system (e.g., Figure 1 ) to the input of the processor 200 and / or from the processor 200 to other processors and / or components included in the system (e.g., the control panel 152 and scan converter 130 shown in FIG. Figure 1 138 and the output of the volume renderer 134) shown in FIG. Controller 214 can control the data paths in ALU 204, FPLU 206, and / or DSPU 208. Controller 214 can be implemented as one or more state machines, data paths, and / or dedicated control logic. The gates of controller 214 can be implemented as independent gates, FPGAs, ASICs, or any other suitable technology.

[0044] Registers 212 and cache 210 may communicate with controller 214 and core 202 via internal connections 220A, 220B, 220C, and 220D. The internal connections may be implemented as buses, multiplexers, crossbar switches, and / or any other suitable connection technology.

[0045] The input and output of the processor 200 may be provided via a bus 216, which may include one or more conductors. The bus 216 may be communicatively coupled to one or more components of the processor 200, such as the controller 214, the cache 210, and / or the registers 212. The bus 216 may be coupled to one or more components of the system, such as the aforementioned display 138 and the control panel 152.

[0046] The bus 216 may be coupled to one or more external memories. The external memory may include a read-only memory (ROM) 232. The ROM 232 may be a mask ROM, an electrically programmable read-only memory (EPROM), or any other suitable technology. The external memory may include a random access memory (RAM) 233. The RAM 233 may be static RAM, battery-backed static RAM, dynamic RAM (DRAM), or any other suitable technology. The external memory may include an electrically erasable programmable read-only memory (EEPROM) 235. The external memory may include flash memory 134. The external memory may include a magnetic storage device, such as a disk 236. In some examples, the external memory may be included in the system, for example Figure 1 The ultrasound imaging system 100 shown in FIG. 1 , for example, the local memory 142 .

[0047] Figure 33 is an illustration of example images 300 and 302 of a dual-level resolution CEUS system according to the principles of the present disclosure. Images 300 and 302 were acquired from a kidney 304 (an organ having a vascular tree). Image 300 illustrates a first imaging mode, which is contrast-enhanced color Doppler imaging of the large arteries and veins. Image 302 illustrates a second imaging mode, SRI mode for microstructure 306 and targeted microcirculation. In some embodiments, images 300 and / or 302 may be provided as part of a sequence of images (e.g., a video playback).

[0048] Image 300 provides an overview of substantially the entire organ with suspicious areas that may require additional investigation. A user may investigate these suspicious areas by selecting an ROI within image 300 via a user interface (user interface 124). Figure 3 In the example shown in , the ROI is selected by placing a rectangular box 308 within the image 300. In some examples, the rectangular box 308 can be moved around during the interactive investigation.

[0049] Image 302 is an example of a magnified, detailed blood vessel map with both structural and functional information about capillary flow dimensions obtained via SRI. In some examples, processing the ultrasound image to generate the SRI image may be performed by an image processor, such as image processor 136.

[0050] In some examples, images 300 and 302 can be generated without switching between different imaging modes, for example, by interleaving the acquisition of ultrasound signals used to generate corresponding images in images 300 and 302. In some examples, the interleaving of these visualizations can be closely related to the pulse sequence used for one or both of images 300 and 302 and / or post-processing. In some examples, the imaging pulse sequence can be primarily determined by the location of the large area on image 300 for color Doppler imaging, and the post-processing and contrast recording time can be primarily regulated by the level of spatial resolution on image 302.

[0051] Figure 4 is an illustration of example images 400 , 402 , 404 , 406 of a multi-level resolution CEUS system in accordance with the principles of the present disclosure. Figure 4The image in FIG. 4 shows a tumor 408 in the liver. Image 400 is a grayscale contrast imaging image with high temporal resolution but low spatial resolution, which can be useful for observing the contrast wash-in dynamics of tumor 408. Image 402 shows a high-definition cumulative imaging image within the ROI indicated by box 410. The image within box 410 has intermediate temporal resolution and intermediate spatial resolution, which can provide better vascular clarity of large and small arteries in the tumor. In some examples, the image in box 410 can be generated by HD-MVI. Example systems and methods that can be used to generate HD-MVI images are described in U.S. Provisional Patent Application No. 62 / 787860.

[0052] Image 404 shows a second ROI indicated by box 412 placed within box 410. Image 406 is an image generated from the second ROI. Image 406 is a low temporal resolution, high spatial resolution SRI image, which can allow for visualization of microstructure and orientation of microcirculation. The lower temporal resolution can be due, at least in part, to the large number of frames that are combined to generate the SRI image. However, this large number of frames (e.g., 40,000 frames) can provide higher spatial resolution.

[0053] The terms "high", "low", and "intermediate" are used to refer to the resolution of an image. Figure 4 402 . Thus, in some examples, an image having a higher temporal resolution may combine fewer frames and / or have a higher acquisition rate than an image having an intermediate or lower temporal resolution. Similarly, in some examples, an image having a higher spatial resolution may combine more frames and / or have more densely spaced scan lines than an image having an intermediate or lower spatial resolution. Furthermore, although the ROI for image 406 is shown here as being selected on the intermediate image 402 , in some examples, the ROI for the low temporal, high spatial resolution SRI image may be selected on the first image 400 and the intermediate images and associated steps may be omitted.

[0054] In some examples, image 406 may pop up (eg, a pop-up window) within or near image 404. In some examples, the ROI indicated by box 410 and / or box 412 may be moved around by the user during an investigation.

[0055] As previously described, the SRI image is an accumulation of the center positions of microbubbles and therefore a probability density map of the microbubbles. In some examples, a confidence score may be generated based on a probability density calculation of the center positions of the microbubbles. For example, a confidence score may be calculated based on a correlation map between two or more consecutive frames used to generate the SRI image. In some examples, the correlation value between two consecutive frames may be averaged across multiple correlation values ​​calculated for consecutive pairs of frames used to generate the SRI image. The correlation may be normalized to a value between 0 and 1. The normalized correlation value may be used as a confidence score. This confidence score may indicate that a sufficient number of frames have been accumulated for generating the SRI image and / or that the motion during the frame accumulation period is sufficiently low. In some examples, a confidence score and / or a qualitative indication of the confidence score may be provided to the user. In Figure 4 In the example shown in , a ring 414 around the image 406 provides a qualitative indication of the confidence score by displaying different colors corresponding to different confidence score ranges. For example, if the confidence score is below a threshold (e.g., 0.8, 0.9), the ring 414 may be a first color (e.g., red), and if the confidence score is equal to or exceeds the threshold, the ring 414 may be a second color (e.g., green). Additional colors and thresholds may be used.

[0056] like Figure 3 and 4 As shown, according to the principles of the present disclosure, there are multiple ways to reconstruct and display multi-level vascular images. In some examples, once an ROI is selected, a new level of vascular imaging within the selected "large" ROI pops up and replaces the current level image. In another example, once an ROI is selected, a new level of vascular imaging within the selected "small" ROI pops up and can be displayed in a new window next to the current level image. In some examples, the two aforementioned examples can be combined. As previously described, there can be multiple control and / or display components for the user interface (e.g., user interface 124). The ROI can be selected using a pointer and / or mouse, or interactively drawn by a finger on the touch image panel.

[0057] like Figure 4As illustrated in the example shown in , there are three levels of resolution: the first level of resolution imaging is typically real-time CEUS used to overview and then determine the "large" ROI shell of the tumor and its blood supply vessels. Once the user indicates contrast agent injection via the user interface, all contrast image frames can be collected and processed by the image processor (e.g., image processor 136). The second level of resolution imaging is a cumulative imaging mode, in which its resolution is enhanced using microbubble localization and tracking technology (e.g., HD-MVI). Once the "large" ROI window is selected, the HD-MVI image within the window will be continuously updated using image frames acquired before and after the ROI selection. In some examples, the time interval for imaging accumulation can be controlled by the user via the user interface. The third level of resolution imaging is a super-resolution imaging (SRI) mode. Once a "small" ROI is selected, the SRI image within the pop-up window will be updated until enough image frames are collected (wherein the image frames are acquired before and after the ROI selection).

[0058] Figure 5 is a flow chart 500 of a method according to the principles of the present disclosure. In some examples, the method may be Figure 1 The system 100 shown in FIG.

[0059] At block 502, a step of receiving a plurality of ultrasound images may be performed. In some examples, the ultrasound images may be received by an image processor, such as image processor 136. At block 504, a step of displaying at least one of the plurality of ultrasound images may be performed. In some examples, the ultrasound images may be displayed on a display, such as display 138.

[0060] At block 506, a step of "receiving an indication of a ROI" may be performed. In some examples, the ROI may be indicated within at least one of the plurality of ultrasound images. In some examples, the ROI includes less than the entirety of at least one of the plurality of ultrasound images. In some examples, the indication may be user input received via a user interface, such as user interface 124. In some examples, a user may use control panel 152 to provide user input to indicate the ROI.

[0061] At block 508, the step of processing the first set of multiple ultrasound images using a first processing technique may be performed. At block 510, the step of processing the second set of multiple ultrasound images in the ROI using a second processing technique may be performed. In some examples, the processing may be performed by an image processor. In some examples, the second processing technique may have a higher spatial resolution and a lower temporal resolution than the first processing technique. In some examples, the first set and the second set include the same images. In some examples, the first processing technique may be a contrast-enhanced ultrasound processing technique, and the second processing technique may be a super-resolution imaging (SRI) processing technique. In other examples, the first processing technique may be a Doppler processing technique. In some examples, block 510 may be performed before block 508. In some examples, blocks 508 and 510 may be performed simultaneously.

[0062] In some examples, Figure 5 The method shown in may further comprise displaying the image processed by the first and / or second processing technique, for example on a display.

[0063] Optionally, in some examples, Figure 5 The method shown in can also include calculating a confidence score when the second processing technique is an SRI processing technique. The confidence score can be based at least in part on the SRI processing technique. In some examples, the confidence score can be displayed with the ultrasound image. In some examples, for example, the confidence score can be qualitatively provided as a reference Figure 4 The colored ring in question.

[0064] In some examples, Figure 5 The method shown in may also include acquiring ultrasound signals for generating the plurality of ultrasound images. The acquisition may be performed by an ultrasound transducer array, such as the transducer array 114 included in the ultrasound probe 112. In some examples, the acquisition may be under the control of a transmit controller, such as the transmit controller 120. In some examples, the control signal may indicate one or more pulse sequences. In some examples, the acquisition of ultrasound signals for generating a first set of the plurality of ultrasound images is interleaved with the acquisition of ultrasound signals for generating a second set of the plurality of ultrasound images. For example, the interleaving may be based on a control signal provided to the ultrasound probe by the transmit controller. In some examples, Figure 5 The method shown in may also continuously stream data corresponding to the ultrasound signal to a computer-readable medium, such as local memory 142 .

[0065] Two non-limiting examples of interleaved acquisition are provided herein to illustrate the principles of the present disclosure. In the first example, frame-to-frame interleaving is performed. In this form of interleaving, one or more frames of a first imaging type are acquired, followed by one or more frames of a second imaging type. In some applications, this may be followed by the acquisition of one or more frames of a third imaging type. The acquisition sequence is then repeated for the duration of the scan, or at least as long as images of a different imaging mode are desired. For example, B-mode frames (which can be displayed as "non-linear" angiographic images of microbubbles or "linear" anatomical images of tissue, or both), color imaging frames (e.g., Doppler power or velocity maps, or both), and / or multiple SRI frames can be selectively placed together in one or more frame-to-frame sequences in any order. In some cases, the SRI image can be an accumulation of many ultra-rapid imaging frames.

[0066] In a second interleaving example, all acquired frames are identical (e.g., each frame is used for B-mode and / or color Doppler, SRI). That is, the acquisition parameters used to generate different images can be the same. For example, an ultra-rapid imaging frame can include multiple beams and / or directions and / or multiple pulses transmitted and received along each beam or direction. In some examples, the pulses can be different (e.g., different frequencies, durations, intensities). The received pulses from multiple frames can then be extracted and / or accumulated to form images for different imaging modes (e.g., B-mode, color Doppler, and / or SRI images). For example, if the transmit pulse waveforms for B-mode, color Doppler, and SRI are different, the pulses for B-mode, color Doppler, and SRI can be transmitted sequentially along the same beam or direction. In another example, if the transmit pulse waveform for B-mode or color Doppler is the same as part of the SRI waveform, then a pulse for SRI alone may be sufficient.

[0067] Optionally, in some examples, Figure 5 The method shown in may further include receiving an indication of a second ROI, for example, via a user interface. The method may further include processing a third set of multiple ultrasound images in the second ROI using a third processing technique. Again, the processing may be performed by an image processor. In some examples, the third processing technique may have a higher spatial resolution and a lower temporal resolution than the first processing technique and a lower spatial resolution and a higher temporal resolution than the second processing technique.

[0068] Advantages of multi-level vascular imaging according to the principles of the present disclosure may include adequate display of spatially detailed microvasculature within a small ROI, shortened processing time for SRI reconstruction to facilitate display of microstructure, and allowing effective correction of local physiological motion that may be important in SRI.

[0069] In various examples of implementing components, systems, and / or methods using programmable devices such as computer-based systems or programmable logic, it should be appreciated that the systems and methods described above can be implemented using various known or later developed programming languages ​​such as "C," "C++," "FORTRAN," "Pascal," "VHDL," and the like. Accordingly, various storage media, such as magnetic computer disks, optical disks, electronic memory, and the like, can be prepared that can contain information that can direct a device, such as a computer, to implement the systems and / or methods described above. Once an appropriate device accesses the information and programs contained on the storage medium, 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 material (such as source files, object files, executable files, and the like) is provided to a computer, the computer can receive the information, configure itself appropriately, and perform the functions of the various systems and methods outlined in the above figures and flowcharts to implement the various functions. That is, the computer can receive various portions of the information relating to the different elements of the systems and / or methods described above from the disk, implement the individual systems and / or methods, and coordinate the functions of the individual systems and / or methods described above.

[0070] 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 / or firmware. In addition, the various methods and parameters are included only by way of example and not in any limiting sense. In view of the present disclosure, one of ordinary skill in the art can implement this teaching to determine their own techniques and the equipment required to implement these techniques while remaining within the scope of the present invention. The functions of one or more of the processors described herein can be incorporated into a smaller number or a single processing unit (e.g., a CPU) and can be implemented using an application specific integrated circuit (ASIC) or a general-purpose processing circuit that is programmed in response to executable instructions that perform the functions described herein.

[0071] Although the present system may have been described with particular reference to ultrasound imaging systems, it is contemplated that the present system may be extended to other medical imaging systems in which one or more images are obtained in a systematic manner. Thus, the present system may be used to obtain and / or record image information relating to, but not limited to, the kidneys, testicles, breasts, ovaries, uterus, thyroid, liver, lungs, musculoskeletal system, spleen, heart, arteries, and vascular system, as well as other imaging applications related to ultrasound-guided interventions. 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. Certain additional advantages and features of the present disclosure will be apparent to those skilled in the art upon studying the present disclosure, or may be experienced by those employing the novel systems and methods of the present disclosure. Another advantage of the present system and method may be that conventional medical imaging systems can be easily upgraded to incorporate the features and advantages of the present systems, devices, and methods.

[0072] Of course, it should be understood that any of the examples, paradigms, or processes described herein may be combined with one or more other examples, paradigms, and / or processes, or may be separated and / or performed in separate devices or device portions, in accordance with the present systems, devices, and methods.

[0073] Ultimately, the above discussion is intended to be merely illustrative of the present system and method and should not be construed as limiting the appended claims to any particular example or group of examples. Thus, while the present system has been described in detail with reference to illustrative examples, it should be appreciated that numerous modifications and alternative examples may be devised by those skilled in the art without departing from the broader and intended spirit and scope of the present system and method as set forth in the claims. Accordingly, the specification and drawings are to be regarded in an illustrative manner and are not intended to limit the scope of the claims.

Claims

1. An ultrasound imaging system (100), comprising: a display (138) configured to display at least one ultrasound image of a plurality of ultrasound images generated by an ultrasound probe (112) for transmitting and receiving ultrasound signals, wherein the plurality of ultrasound images are contrast-enhanced ultrasound images; a user interface (124) configured to receive user input via at least one user control (152), wherein the user input indicates a first region of interest (ROI) within the at least one of the plurality of ultrasound images, wherein the first ROI includes less than an entirety of the at least one of the plurality of ultrasound images; and at least one processor (136) in communication with the user interface, the at least one processor being configured to: processing at least some of the plurality of ultrasound images using a first processing technique, wherein the first processing technique is a contrast-enhanced ultrasound processing technique; processing at least some of the plurality of ultrasound images in the first ROI using a second processing technique, wherein the second processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique, wherein the second processing technique is a super-resolution imaging (SRI) processing technique; and generating a confidence score based at least in part on the second processing technique, wherein the super-resolution imaging processing technique includes accumulation of center positions of microbubbles from the contrast-enhanced ultrasound processing technique, and the confidence score is calculated based on a probability density of the center positions of the microbubbles, wherein the confidence score is an indication of at least one of: a sufficient number of frames having been accumulated to generate an SRI image; and sufficiently low motion during the accumulation of frames, The display is further configured to display the at least some of the multiple ultrasound images processed using the first processing technology and the at least some of the multiple ultrasound images processed using the second processing technology, and Therein, the generated confidence score and / or a qualitative indication of the generated confidence score is provided to a user.

2. The ultrasound imaging system according to claim 1, wherein: The user input also indicates a first imaging mode, wherein the second processing technique is based at least in part on the first imaging mode.

3. The ultrasound imaging system according to claim 2, further comprising: An ultrasound probe (112) configured to transmit and receive ultrasound signals for a plurality of ultrasound images, wherein the plurality of ultrasound images are contrast-enhanced ultrasound images; and A transmit controller (120) is in communication with the ultrasound probe, wherein the transmit controller is configured to provide a control signal to the ultrasound probe to control the transmission or reception of the ultrasound signal, wherein the control signal is based at least in part on the first imaging mode.

4. The ultrasound imaging system according to claim 3, wherein: The control signal indicates a pulse sequence to be transmitted by the ultrasound probe.

5. The ultrasound imaging system according to claim 1, wherein: The user input further indicates a second ROI, and the at least one processor is further configured to process at least some of the plurality of ultrasound images in the second ROI using a third processing technique, wherein the third processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique, and has a lower spatial resolution and a higher temporal resolution than the second processing technique.

6. The ultrasound imaging system according to claim 1, wherein: The confidence score is provided on the display as a ring (414) surrounding the first ROI, wherein a color of the ring is based at least in part on a value of the confidence score.

7. The ultrasound imaging system according to claim 1, wherein: The first ROI is movable within the at least one image of the plurality of ultrasound images.

8. The ultrasound imaging system according to claim 1, wherein: The display is also configured to display at least some of the multiple ultrasonic images processed using the second processing technology as superimposed on at least some of the multiple ultrasonic images processed using the first processing technology, or to display at least some of the multiple ultrasonic images processed using the second processing technology as pop-up items.

9. A method (500) for ultrasound imaging, comprising: receiving a plurality of ultrasound images, wherein the plurality of ultrasound images are contrast-enhanced ultrasound images; displaying at least one ultrasound image among the plurality of ultrasound images; receiving an indication of a region of interest (ROI) within the at least one ultrasound image of the plurality of ultrasound images, wherein the ROI comprises less than an entirety of the at least one ultrasound image of the plurality of ultrasound images; processing the first set of the plurality of ultrasound images using a first processing technique, wherein the first processing technique is a contrast-enhanced ultrasound processing technique; processing a second set of the plurality of ultrasound images in the ROI using a second processing technique, wherein the second processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique, wherein the second processing technique is a super-resolution imaging (SRI) processing technique; calculating a confidence score based at least in part on the second processing technique, wherein the super-resolution imaging processing technique includes accumulation of center positions of microbubbles from the contrast-enhanced ultrasound processing technique, and the confidence score is calculated based on a probability density of the center positions of the microbubbles, wherein the confidence score is indicative of at least one of: a sufficient number of frames having been accumulated to generate an SRI image; and sufficiently low motion during the accumulation of frames; providing the calculated confidence score and / or a qualitative indication of the confidence score to a user; and At least some of the multiple ultrasound images processed by using the first processing technology and at least some of the multiple ultrasound images processed by using the second processing technology are displayed.

10. The method according to claim 9, wherein: The first set and the second set include the same image from among the plurality of ultrasound images. The method according to claim 9 , further comprising acquiring ultrasound signals for generating the plurality of ultrasound images.

12. The method of claim 11, further comprising continuously streaming data corresponding to the ultrasound signal to a computer-readable medium.

13. The method according to claim 11, wherein Acquisition of ultrasound signals for generating the first set of the plurality of ultrasound images is interleaved with acquisition of ultrasound signals for generating the second set of the plurality of ultrasound images.

14. The method according to claim 9, further comprising: receiving an indication of a second ROI; A third set of the plurality of ultrasound images is processed in the second ROI using a third processing technique, wherein the third processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique, and has a lower spatial resolution and a higher temporal resolution than the second processing technique.

15. A non-transitory computer-readable medium comprising instructions that, when executed, cause an ultrasound imaging system to: Receive multiple ultrasound images, where: The ultrasound image is a contrast-enhanced ultrasound image; displaying at least one ultrasound image among the plurality of ultrasound images; receiving an indication of a region of interest (ROI) within the at least one ultrasound image of the plurality of ultrasound images, wherein the ROI comprises less than an entirety of the at least one ultrasound image of the plurality of ultrasound images; processing the first set of the plurality of ultrasound images using a first processing technique, wherein the first processing technique is a contrast-enhanced ultrasound processing technique; processing a second set of the plurality of ultrasound images in the ROI using a second processing technique, wherein the second processing technique has a higher spatial resolution and a lower temporal resolution than the first processing technique, wherein the second processing technique is a super-resolution imaging (SRI) processing technique; generating a confidence score based at least in part on the second processing technique, wherein the super-resolution imaging processing technique includes accumulation of center positions of microbubbles from the contrast-enhanced ultrasound processing technique, and wherein the confidence score is based on a probability density calculation of the center positions of the microbubbles, wherein the confidence score is indicative of at least one of: a sufficient number of frames having been accumulated to generate an SRI image; and sufficiently low motion during the accumulation of frames; providing the calculated confidence score and / or a qualitative indication of the confidence score to a user; and At least some of the multiple ultrasound images processed by using the first processing technology and at least some of the multiple ultrasound images processed by using the second processing technology are displayed.

Images