Ultrasound medical imaging with sound velocity optimized based on fat fraction

Abstract

For ultrasound imaging (38) using an ultrasound scanner (10), the fat fraction of the tissue is measured (30). The fat fraction can be measured (30) without access to channel data such as from beamformed data. The speed of sound varies with the fat fraction of the tissue, so the fat fraction is used to set the speed of sound in beamforming (34). Imaging the tissue (38) using a fat fraction-based optimization for the speed of sound can provide better images than imaging (38) at an assumed speed.

Description

[0001] This application is a divisional application. The name of the invention of the parent case is “Ultrasound medical imaging with sound speed optimized based on fat fraction”. The application date is June 24, 2020, and the application number is 202010587680.7. Background Art

[0002] This embodiment relates to ultrasound imaging of soft tissue. In ultrasound imaging of soft tissue (such as liver imaging), the speed of sound is assumed to be 1540 m / s in the tissue. This assumed speed of sound is used for focusing or beamforming in ultrasound scanning using an array. For different tissues and / or patients, the actual speed of sound is different. As a result, the assumed 1540 m / s may result in suboptimal images.

[0003] The speed of sound is difficult to measure with ultrasound. Typically, an assumed velocity is used. Instead, the speed of sound used in beamforming is derived by varying to several discrete values. The value that produces the best image quality based on a combination of measures of image brightness, contrast, lateral resolution, and lateral bandwidth may be selected. These measurements require access to channel data that may not be available. Summary of the invention

[0004] By way of introduction, the preferred embodiments described below include methods, instructions, and systems for ultrasound imaging using an ultrasound scanner. The fat fraction of a tissue is measured. The fat fraction can be measured without access to channel data, such as data from beamforming. The speed of sound varies with the fat fraction of the tissue, so the fat fraction is used to set the speed of sound in beamforming. Imaging the tissue using optimization based on the fat fraction can provide better images than imaging at an assumed velocity.

[0005] In a first aspect, a method for ultrasound imaging using an ultrasound scanner is provided. A fat fraction of a patient's liver is estimated. A speed of sound of the liver is determined from the fat fraction. A beamformer of the ultrasound scanner is configured based on the determined speed of sound. The patient's liver is imaged using the beamformer as configured based on the determined speed of sound.

[0006] In a second aspect, a system for ultrasonic medical imaging is provided. A beamformer is configured to scan tissue in a patient using a transducer based on a first sound velocity and a second sound velocity. An image processor is configured to estimate a value of a fat fraction of the patient's tissue from beamformed samples output by the beamformer using the first sound velocity, set a second sound velocity from the fat fraction, and generate an image of the tissue from the beamformed samples output by the beamformer using the second sound velocity set from the fat fraction. A display is configured to display the image of the tissue.

[0007] In a third aspect, a method for optimizing the speed of sound in an ultrasound medical scanner is provided. The fat fraction of tissue in a patient is measured. A beamformer focus distribution is set based on the fat fraction. The tissue of the patient is scanned by the ultrasound medical scanner using the beamformer focus distribution. An image of the tissue is generated from the scanned results.

[0008] The present invention is defined by the appended claims, and nothing in this section should be considered a limitation on those claims.Additional aspects and advantages of the present invention will be discussed below in conjunction with the preferred embodiments, and may be claimed later, either independently or in combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The components and drawings are not necessarily drawn to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the different views.

[0010] Figure 1 is a flow chart of one embodiment of a method for performing ultrasound imaging with an ultrasound scanner using a sound velocity optimized according to fat fraction; and

[0011] Figure 2 is a block diagram of one embodiment of a system for ultrasound medical imaging using sound velocity from fat fraction. DETAILED DESCRIPTION

[0012] Ultrasound liver or other soft tissue imaging uses an optimized speed of sound based on measured fat fraction. The fat fraction can be ultrasound derived. The beamformed speed of sound is adapted to the bioacoustic variations of each patient based on the measured fat fraction of that patient. Studies have shown that the speed of sound in the liver is proportional to the fat fraction. The beamformed speed of sound is based on an ultrasound derived automatic measurement or other metric of the fat fraction of the imaged tissue.

[0013] Figure 1 An embodiment of a method for ultrasound imaging using an ultrasound medical scanner is shown. The speed of sound is optimized based on fat fraction. The ultrasound medical scanner uses the speed of sound based on fat fraction to image tissue, thereby providing an improved image compared to using a default speed of sound. A better or more accurate diagnosis by a doctor or sonographer can result from the improved image of the patient's tissue.

[0014] Method by Figure 2The medical diagnostic ultrasound scanner performs measurements by acoustically generating waves and measuring responses using a beamformer. An image processor of a scanner, computer, server, or other device estimates fat fraction, determines the speed of sound, configures a beamformer based on the determined speed of sound, scans tissue using the configured beamformer, and generates an image. A display device, network, or storage is used to output the estimated image.

[0015] Additional, different or fewer actions may be provided. For example, action 38 may not occur. The actions may be performed in the order described or shown (e.g., from top to bottom or numerically), but may also be performed in other orders.

[0016] In act 30, a processor, such as an image processor, estimates or measures the fat fraction of the patient's tissue. The estimate or measurement is made by scanning the patient. Alternatively, the estimate or measurement is made by looking up, such as from the patient's computerized medical record. The estimate or measurement is obtained from a database, memory, computer network transmission, or patient scan.

[0017] The fat fraction is patient specific. One or more characteristics of a patient are used to obtain the fat fraction of the patient. Some patients may have the same or similar fat fractions, but different patients may have different fat fractions.

[0018] In one embodiment, the tissue is the patient's liver. Obtain the fat score of the patient's liver. Liver is used as an example herein. In other embodiments, the tissue is from the patient's kidney, bladder, breast, heart, muscle or other soft tissue.

[0019] The fat fraction can be obtained from a magnetic resonance scan of the patient, such as measured with a magnetic resonance proton density fat fraction (MR-PDFF) scan. Other modalities can be used to measure or estimate the fat fraction. In another embodiment, the fat fraction is obtained from an ultrasound scan. Since the fat fraction is used to determine the speed of sound in tissue (e.g., liver tissue) for ultrasound imaging, an ultrasound scanner that estimates or measures the fat fraction can be more economical and time-effective and more convenient.

[0020] In one embodiment, for ultrasonic estimation of fat fraction of tissue, an ultrasound medical scanner determines scattering and attenuation from the scanned tissue. Other combinations of quantitative ultrasound parameters may be used. Multiple quantitative ultrasound parameters may be used to measure the complexity of human tissue in order to accurately characterize the tissue. For example, liver fat fraction is estimated using a multi-parameter approach that combines quantitative parameters extracted from received signals of different wave phenomena, such as scattering and attenuation of longitudinal waves, propagation and attenuation of shear waves, and / or propagation and attenuation of on-axis waves from acoustic radiation force impulse (ARFI) excitation. U.S. Published Patent Application No. 2018 / 0289323 discloses the use of ultrasound to estimate fat fraction.

[0021] In one embodiment, liver fat fraction is estimated by estimating scattering parameters by transmitting and receiving a pulse sequence and obtaining shear wave parameters by transmitting and receiving a pulse sequence. The estimation may include transmitting and receiving a pulse sequence to estimate parameters based on the axial displacement caused by an acoustic radiation force impulse (ARFI). The parameters are estimated and combined to estimate fat fraction. Other information, such as non-ultrasound data (e.g., blood biomarkers), may be included in the estimation of fat fraction. A lookup table based on empirical studies may be used to relate the values ​​of various parameters to the value of fat fraction.

[0022] Ultrasound scanners generate a measure of scattering in tissue from a scan of a patient. To measure scattering, an ultrasound scanner scans the tissue using ultrasound. A sequence of transmit and receive events is performed to acquire signals to estimate quantitative ultrasound scattering parameters. These parameters measure the response of the tissue to the longitudinal waves transmitted from the ultrasound scanner. The scattering or echoes of the longitudinal waves impinging on the tissue are measured.

[0023] Any scattering measure may be used, such as the spectral slope of the logarithm of the frequency-dependent backscatter coefficient. For example, the attenuation coefficient is measured. A reference phantom method is used, but other measures of the attenuation coefficient may be used. The acoustic energy has an exponential decay as a function of depth. A measure of the acoustic intensity as a function of depth is performed before or without depth gain correction. To eliminate systematic effects, the measurement is calibrated based on a measure of the acoustic intensity as a function of depth in the phantom. By averaging over a one-dimensional, two-dimensional, or three-dimensional area, the measurement can withstand less noise. The beamformed samples or acoustic intensities can be converted to the frequency domain and calculations performed in the frequency domain.

[0024] Attenuation is measured as the slope of intensity as a function of depth. Other attenuation metrics may be used, such as the attenuation of shear waves with distance or time. Tissue displacement as a function of depth from ARFI-induced longitudinal waves can be used to find the attenuation of tissue. The amount of maximum displacement, displacement as a function of depth, and / or displacement as a function of time are used to calculate attenuation. Other propagation metrics may also be used instead of or in addition to attenuation. For example, a metric of shear wave propagation or a metric of on-axis displacement (e.g., an ARFI metric) may be used.

[0025] The fat fraction can be determined from attenuation and scatter or from other combinations of quantitative ultrasound information. The values ​​of the attenuation or propagation and backscatter measurements are input to a machine learning classifier or lookup table, which outputs a value for the fat fraction. The machine trained classifier provides a non-linear model. The lookup table can provide a linear model. A predetermined or programmed function relates the input values ​​to the output values. The function and / or the weights used in the function can be experimentally determined. For example, the weights are obtained by least square minimization using magnetic resonance proton density fat fraction (MR-PDFF) values.

[0026] Other methods of measuring fat fraction using ultrasound medical scanners may be used. To make measurements using ultrasound, the scanner's beamformer is configured for scanning. The focus of the transmit and receive beams, including dynamic focusing on receive, is based on a delay or phase distribution. Distance and speed of sound are used to determine the amount of phase or delay applied to the signal from or to each element of the element array used for focusing.

[0027] The sound velocity used to measure the fat fraction is the current sound velocity. For example, a default sound velocity value (e.g., 1540 m / s) is used. A beamformer focus distribution for a given focal position and sound velocity is selected and used by the beamformer in transmit and / or receive focusing. Different distributions are used for different focal positions and / or different sound velocities. In another example, a sound velocity previously set based on a previous measurement of fat fraction is used. The scan to measure the fat fraction is based on the current value of the sound velocity.

[0028] Imaging can occur while the fat fraction is being measured or estimated. For example, B-mode imaging is performed to place and maintain the field of view of the transducer at the desired tissue. Once the field of view is at the desired location in the patient, a scan is performed to estimate the fat fraction. Imaging continues while the fat fraction is being estimated. Alternatively, imaging is stopped while the fat fraction is being estimated.

[0029] In act 32, a processor, such as an image processor, determines the speed of sound of the tissue (eg, liver) based on the fat fraction. The fat fraction, with or without another variable or variables, is used to determine the speed of sound.

[0030] A calculation can be used. A function that relates the fat fraction to the speed of sound is used. By knowing the value of the fat fraction, the speed of sound is calculated. For example, the Wood equation can be used, which is a function that relates the speed of sound to density and fat fraction:

[0031]

[0032] where c is the speed of sound, is the fat fraction, ρ f is the fat density, ρ b is the background material density, k f is the fat mass modulus, and k b is the background material bulk modulus. Density and bulk modulus are assumed. Alternatively, the density is measured, such as from average attenuation or backscattering, or derived from the bulk modulus. Other functions may be used.

[0033] Instead of calculation, a lookup table or other model relating fat fraction to speed of sound may be used. Other models may include a machine learning classifier that is trained to output speed of sound based on an input of fat fraction with or without other inputs. As a lookup table, fat fraction may be input to directly output or look up speed of sound. In one example, a range of fat fractions (e.g., % of tissue is fat) measured from ultrasound (i.e., ultrasound determined fat fraction (UDFF)) is directly mapped to speed of sound (SOS). This example table may be:

[0034] UDFF(%)=[0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 35-40]

[0035] SOS(m / s)=[1540,1520,1510,1500,1490,1480,1470,1460],

[0036] Where 0-5% UDFF maps to a SOS of 1540 m / s, 5-10% UDFF maps to a SOS of 1520 m / s, etc. Other tables relating different values ​​and / or ranges to one another may be used.

[0037] A value for the speed of sound is determined. Alternatively, a beamformer focus profile is determined as the speed of sound. One or more profiles using an appropriate speed of sound are selected.

[0038] In act 34, a processor such as an image processor and / or a beamformer controller configures a beamformer of the ultrasound scanner based on the determined speed of sound. The beamformer uses the speed of sound for focusing transmit and / or receive beams during ultrasound scanning. Any type of ultrasound scanning may be provided, such as B-mode or Doppler (e.g., color or flow mode).

[0039] The beamformer uses a delay and / or phase profile for each focal position used in transmission and / or reception. The profiles are the same or different for different positions. The profiles are based in part on the distance from the corresponding element to the focal position in the patient. The profiles are also based on the speed of sound to provide the propagation time of the acoustic energy from the element to the focal position and / or from the focal position to the element (i.e., the speed of the acoustic energy along that distance). The speed of sound is used to configure the beamformer with the desired delay and / or one or more phase profiles for scanning imaging.

[0040] A beamformer focus distribution (e.g., delay or phase distribution) is set based on the fat score. The beamformer of the ultrasound medical scanner is configured to operate at a given sound speed based on the fat score. The sound speed itself is set and the distribution is calculated from it, or the fat score is mapped to one or more focus distributions that incorporate the sound speed. In either method, the sound speed is determined from the fat score. The beamformer focus distribution is based on the sound speed.

[0041] Rather than continuing to use a current or default sound velocity, a sound velocity based on a measured or estimated fat fraction is used. A sound velocity value or a distribution of combined sound velocities is altered (e.g., changed or replaced) based on the fat fraction. The altered value or distribution is for a sound velocity based on the fat fraction of the imaged patient for subsequent imaging.

[0042] In action 36, an ultrasonic medical scanner scans the tissue of a patient. A beamformer configured by one or more focal distributions transmits an acoustic beam and / or forms a receive beam from an acoustic echo. An array of elements of a transducer transduces between acoustic energy and electrical energy. The beamformer includes channels connected to the elements. The beamformer generates relatively delayed or phased electrical waveforms for the elements of the transmit aperture using the focal distribution. The transducer converts the electrical waveform into acoustic energy, which causes constructive interference at the focal position and along the scan line as a transmit beam. The acoustic echo received at the element is converted into an electrical signal of the channel. The beamformer relatively delays and / or phases the electrical signals from different elements in the receive aperture and combines the delayed or phased signals. A dynamic focus may be used, where the focus is shifted over time along the receive line by using different focal distributions due to different positions. The combination of beamforming provides beamformed samples for various positions along the receive scan line or for the receive beam.

[0043] One or more focus profiles based on the speed of sound are used for transmit and / or receive beamforming. The beamformer controller uses the speed of sound to calculate relative delays and / or phases during beamforming, or loads a pre-created profile using the speed of sound. The one or more focus points used during scanning are established by the beamformer focus profiles.

[0044] In act 38, an ultrasound medical scanner or processor (e.g., an image processor of a medical scanner) generates an image of the tissue based on the scan results. ) scanned beamformed samples are used to generate an image. The beamformed samples are detected, such as a B-mode detector determines the intensity represented by different beamformer samples. In other modes, scans from the same location at different times are used to estimate the velocity, power and / or variance of the flow or motion from the beamformed samples. Any detection or imaging mode may be used.

[0045] The detected data may be filtered temporally and / or spatially. The detected data may be scan converted into a Cartesian grid format such as a display. The detected data may be mapped to color values ​​for display, such as grayscale values ​​for B-mode imaging or values ​​of different shades of different colors for color flow or Doppler imaging. An image representing the spatial distribution of tissue response to acoustic energy is generated.

[0046] In one embodiment, the image is an image of the liver. For example, a B-mode image is generated that shows the intensity of acoustic returns as a function of a one-dimensional, two-dimensional, or three-dimensional distribution of locations. As another example, a color flow or Doppler image is generated that shows blood or fluid flow in liver tissue. In yet other embodiments, the image includes some locations from the B-mode response and other locations from the Doppler or flow response.

[0047] The image is generated in response to or from data based on sound velocity beamforming. The scan used for imaging is configured by the beamformer based on the sound velocity derived from the fat fraction. B-mode and / or Doppler scanning using the sound velocity based on the fat fraction results in images with fewer or less intense (less noticeable) artifacts caused by incorrectly assuming the sound velocity in the tissue.

[0048] Imaging is performed after the beamformer is configured based on the determined speed of sound. Imaging can continue from before to after the reconfiguration without interruption due to the newly determined speed of sound. Alternatively, a user is notified of the change and the gap in imaging occurs. Imaging after the beamformer configuration change can provide a diagnostic ultrasound image with more diagnostic information than imaging before the change.

[0049] The ultrasound scanner or display device may display the image. Other information may include an image representing the patient's anatomy. For example, an annotation, highlighting, colorization, or overlay showing a value representing fat fraction may be displayed.

[0050] In an alternative embodiment, the generated image is stored or transmitted via a computer network. For example, the image is transmitted for storage in a patient's computerized medical record in a medical record database.

[0051] Figure 2 An embodiment of a system 10 for ultrasonic medical imaging is shown. The system 10 implements Figure 1 The tissue (such as liver tissue) is scanned to measure the patient's fat fraction. The fat fraction is used to configure the transmit beamformer 12 and / or receive beamformer 16 to operate using an acoustic velocity appropriate for the fat fraction of the tissue.

[0052] The system 10 includes a transmit beamformer 12, a transducer 14, a receive beamformer 16, an image processor 18, a display 20, and a memory 22. Additional, different, or fewer components may be provided. For example, a user input is provided for user interaction with the system.

[0053] System 10 is a medical diagnostic ultrasound imaging system. In alternative embodiments, system 10 is a personal computer, workstation, picture archiving and communication system (PACS) station, or other device for real-time or post-acquisition imaging at the same location or distributed over a network.

[0054] The transmit and receive beamformers 12, 16 form beamformers for scanning (eg, transmit and receive operations) using the transducer 14. Based on the operation or configuration of the beamformer, a pulse sequence is transmitted and a response is received. The beamformer scans to measure fat fraction and image tissue.

[0055] The transmit beamformer 12 is an ultrasound transmitter, a memory, a pulse generator, an analog circuit, a digital circuit, or a combination thereof. The transmit beamformer 12 is operable to generate waveforms of multiple channels with different or relative amplitudes, delays, and / or phasing. When acoustic waves are emitted from the transducer 14 in response to the generated electrical waveforms, one or more beams are formed. A transmit beam sequence is generated to scan a two-dimensional or three-dimensional area. Sector, Linear or other scan formats. The same area can be scanned multiple times using different scan line angles, F numbers, and / or waveform center frequencies. For flow or Doppler imaging and shear imaging, a scan sequence along the same line or lines is used. In Doppler imaging, the sequence can include multiple beams along the same scan line before scanning adjacent scan lines. For shear imaging, scan or frame interleaving can be used (i.e., scanning the entire area before scanning again). Lines or line interleaving groups can be used. In an alternative embodiment, the transmit beamformer 12 generates plane waves or diverging waves for faster scanning.

[0056] The transducer 14 is an array for generating acoustic energy from an electrical waveform. For an array, the acoustic energy is focused relative to the delay or phasing. A given transmit event corresponds to different elements transmitting acoustic energy at substantially the same time for a given delay.

[0057] The transducer 14 is a 1, 1.25, 1.5, 1.75 or 2 dimensional array of piezoelectric or capacitive film elements. The transducer 14 includes a plurality of elements for transducing between acoustic energy and electrical energy. A receive signal is generated in response to the ultrasonic energy (echo) impinging on the elements of the transducer 14. The elements are connected to the channels of the transmit and receive beamformers 12, 16. Alternatively, a single element with a mechanical focus is used.

[0058] The receive beamformer 16 includes multiple channels with amplifiers, delays and / or phase rotators, and one or more adders. Each channel is connected to one or more transducer elements. The receive beamformer 16 is configured by hardware, firmware, or software to apply relative delays, phases, and / or apodization in response to each imaging transmission to form one or more receive beams. The receive beamformer 16 outputs data representing spatial locations using received signals. The relative delays and / or phasing and summing of the signals from different elements provides beamforming.

[0059] The receive beamformer 16 may include a filter, such as a filter for isolating information at the second harmonic or other frequency band relative to the transmit frequency band. Such information is more likely to include desired tissue, contrast agent, and / or flow information. In another embodiment, the receive beamformer 16 includes a memory or buffer and a filter or adder. Two or more receive beams are combined to isolate information at a desired frequency band, such as the second harmonic, the third fundamental, or another frequency band.

[0060] In coordination with the transmit beamformer 12, the receive beamformer 16 generates data representing the region. By scanning the region of interest with ultrasound, data (eg, beamformed samples) is generated. By repeating the scan, ultrasound data representing the region at different times is acquired.

[0061] The receive beamformer 16 outputs beam summation data representing a spatial position. Data for a single position, a position along a line, a position of a region, or a position of a volume is output. Dynamic focusing can be provided. Data for different types of measurements are acquired through a series of shared or interleaved scans. B-mode or Doppler scans can be performed separately or using some of the same data. Scans for fat fraction estimation can use image data or data acquired for B-mode or Doppler imaging, or data from scans used only for fat fraction estimation can be used.

[0062] The transmit and / or receive beamformers 12, 16 scan tissue within the patient based on the speed of sound. The beamformers 12, 16 are configured by one or more focus distributions 13 that define relative delays and / or phases between channels, waveforms, and / or element signals. The focus distributions 13 are based in part on the speed of sound. By selecting the focus distributions 13 based on the fat fraction, a speed of sound appropriate for the patient's tissue is selected and used. Alternatively, the beamformers 12, 16 calculate the delays and / or phases in real time using the value of the speed of sound. In either embodiment, the delay and / or phase distributions 13 have at least one different delay and / or phase due to the difference in speed of sound.

[0063] Until fat fraction is measured in a given case, the default or previous speed of sound is used. After fat fraction is measured, the speed of sound is changed. The changed speed of sound is used until a new measurement of fat fraction occurs or until tissue imaging is completed. Different speeds of sound are used in different or sequential scans.

[0064] The image processor 18 is a B-mode detector, a Doppler detector, a pulsed wave Doppler detector, a correlation processor, a Fourier transform processor, an application specific integrated circuit, a general purpose processor, a control processor, an image processor, a field programmable gate array, a digital signal processor, an analog circuit, a digital circuit, a combination thereof, or other now known or later developed device for detecting and processing information from a beamformed ultrasound sample for display.

[0065] In one embodiment, the image processor 18 includes one or more detectors and a separate image processor. The separate image processor is a control processor, a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array, a network, a server, a processor group, a combination thereof, or other now known or later developed device for calculating values ​​of different types of parameters based on beamformed and / or detected ultrasound data, for estimating fat fraction based on values ​​from different types of metrics, and for determining sound velocity based on fat fraction. The separate image processor is configured by hardware, firmware, and / or software to perform Figure 1 Any combination of one or more of the actions shown in .

[0066] The image processor 18 is configured to estimate the value of fat fraction based on a combination of different types of parameters. For example, measured scatter parameters and measured shear wave parameters are used. Different types of parameters are measured based on transmit and receive sequences and calculations based on the results. Values ​​of one or more metrics for each of at least two types of parameters (e.g., scatter, attenuation, shear wave propagation, or axial ARFI) are determined. Beamformed samples output by a beamformer using a velocity of sound are used for quantitative measurements (e.g., attenuation and backscatter) that are used to estimate fat fraction.

[0067] The image processor 18 estimates fat fraction based on different types of parameters or measures of tissue response to different types of wavefronts. The estimation applies a machine learning classifier. The input values ​​of the measures with or without other information are used by a learned regression model to output a value of fat fraction. In other embodiments, the image processor 18 uses a weighted combination of parameter values. A linear or nonlinear mapping relates the value of one or more parameters to the value of fat fraction.

[0068] The image processor 18 is configured to set the sound speed according to the fat score. The value of the sound speed or the beamformer focus distribution is set based on the fat score. For example, a lookup table relates the fat score value to the sound speed value or the focus distribution. The image processor 18 then controls the beamformer 12, 16 to use the sound speed (e.g., the sound speed value or the focus distribution based on the sound speed) for subsequent scanning and / or imaging. The image processor 18 can provide the sound speed information to the beamformer controller, directly control the beamformer 12, 16, or provide the fat score to the beamformer controller, which uses the fat score to configure the beamformer 12, 16 to use the sound speed indicated by the fat score.

[0069] The processor 18 is configured to generate one or more images. For example, shear wave velocity, B-mode, contrast agent, M-mode, flow or color mode, ARFI and / or another type of image is generated. The shear wave velocity, flow or ARFI image can be presented alone or as an overlay or region of interest within a B-mode image. The shear wave velocity, flow or ARFI data modulates the color at locations in the region of interest. In the event that the shear wave velocity, flow or ARFI data is below a threshold, the B-mode information can be displayed without modulation by shear wave velocity. The image is an image of the tissue of the beamformed sample from the receive beamformer 16 using the sound velocity output based on the fat fraction.

[0070] Other information is included in the image or is displayed sequentially or substantially simultaneously. For example, a tissue property estimation image is displayed simultaneously with other images. One or more values ​​of fat fraction are mapped to the display information. Where fat fraction is measured at different locations, the fat fraction value may be generated as a color overlay in the region of interest in the B-mode image. Shear wave velocity and fat fraction data may be combined as a single overlay on a B-mode image. Alternatively, the value of the fat fraction is displayed as text or a numerical value near or overlaid on the B-mode or shear wave imaging image. The image processor 18 may be configured to generate other displays. For example, a shear wave velocity image is displayed next to a chart, text, or graphical indicator of the fat fraction. Fat fraction information is presented for one or more locations of the region of interest, rather than in a separate two-dimensional or three-dimensional representation, such as where a user selects a location and the ultrasound scanner then presents the fat fraction for that location.

[0071] The image processor 18 operates in accordance with instructions stored in the memory 22 or another memory for fat fraction estimation, sound velocity determination, scanning and / or imaging controlled based on the determined sound velocity. The memory 22 is a non-temporary computer-readable storage medium. Instructions for implementing the processes, methods and / or techniques discussed herein are provided on a computer-readable storage medium or memory, such as a cache, a buffer, a RAM, a removable medium, a hard drive or other computer-readable storage medium. Computer-readable storage media include various types of volatile and non-volatile storage media. The functions, actions or tasks shown in the figures or described herein are performed in response to one or more sets of instructions stored in or on a computer-readable storage medium. The functions, actions or tasks are independent of a particular type of instruction set, storage medium, processor or processing strategy, and may be performed by software, hardware, integrated circuits, firmware, microcode, etc. operating alone or in combination. Similarly, processing strategies may include multi-processing, multi-tasking, parallel processing, etc.

[0072] In one embodiment, the instructions are stored on a removable media device for reading by a local or remote system. In other embodiments, the instructions are stored in a remote location for transmission over a computer network or over a telephone line. In other embodiments, the instructions may be stored within a given computer, CPU, GPU, or system.

[0073] The display 20 is a device for displaying a one-dimensional or two-dimensional image or a three-dimensional representation, such as a CRT, LCD, projector, plasma or other display. The two-dimensional image represents the spatial distribution in the area. The three-dimensional representation is rendered from the data representing the spatial distribution in the volume. The display 20 is configured by the image processor 18 or other device by inputting the data to be displayed as an image. The display 20 displays an image representing a tissue such as the liver. The image is based on a scan performed at a speed of sound set based on the fat fraction of the tissue being imaged.

[0074] Although the present invention has been described above with reference to various embodiments, it will be appreciated that many changes and modifications may be made without departing from the scope of the invention. Therefore, it is intended that the foregoing detailed description should be considered illustrative rather than restrictive, and it should be understood that it is the following claims including all equivalents that are intended to define the spirit and scope of the present invention.

Claims

1. A method for performing ultrasound imaging using an ultrasound scanner, the method comprising: estimating, by a processor, a fat fraction of a liver of the patient, the fat fraction being estimated based on a combination of ultrasound measurements extracted from the received ultrasound signals, the fat fraction being estimated as a quantitative value; determining, by the processor, a speed of sound in the tissue of the liver based on the quantitative value of the fat fraction; configuring a beamformer of an ultrasound scanner based on the determined speed of sound; as well as The patient's liver is imaged using a beamformer configured based on the determined speed of sound.

2. The method according to claim 1, wherein: The estimation includes making an estimate from scatter and attenuation as measurements obtained from a scan of the liver by an ultrasound scanner.

3. The method according to claim 2, wherein: Scanning of the liver includes scanning using the beamformer configured with a default speed of sound.

4. The method according to claim 2, wherein: The estimated other imaging occurs during the estimation using the other speed of sound, and the imaging using the beamformer configured based on the determined speed of sound occurs after the other imaging.

5. The method according to claim 1, wherein: Determining the speed of sound includes a calculation determined by the processor as a function of utilizing the fat fraction.

6. The method according to claim 1, wherein: Determining the speed of sound includes determining the speed of sound using a lookup table that relates the quantitative value of the fat fraction to the speed of sound.

7. The method according to claim 1, wherein: Configuration includes changing the default sound speed to the determined sound speed.

8. The method according to claim 1, wherein: Imaging includes beamforming samples of signals from elements of the array, wherein the beamforming uses a delay or phase profile based on the determined speed of sound.

9. The method according to claim 1, wherein: The imaging includes B-mode scanning of the liver and generating a B-mode image of the liver from a result of the scanning, and the beamformer is used for the B-mode scanning.

10. A system for ultrasonic medical imaging, the system comprising: Transducer; a beamformer configured to scan tissue within the patient using the transducer based on a first speed of sound in the tissue and a second speed of sound in the tissue; an image processor configured to estimate a percentage of fat fraction of tissue of the patient from the beamformed samples output by the beamformer using a first acoustic velocity, set a second acoustic velocity from the percentage of fat fraction, and generate an image of the tissue from the beamformed samples output by the beamformer using the second acoustic velocity set from the fat fraction; as well as A display is configured to display an image of the tissue.

11. The system according to claim 10, wherein: The beamformer is configured to scan using a delay profile or a phase profile for elements of the array of transducers, the delay profile or the phase profile being set at different times according to the first sound speed and the second sound speed.

12. The system according to claim 10, wherein: The image processor is configured to estimate a percentage of fat fraction using attenuation and backscatter measured from the beamformed sample using the first sound velocity.

13. The system according to claim 10, wherein: The image processor is configured to set the second sound speed according to a lookup table that relates the percentage of fat fraction to the sound speed.

14. The system according to claim 10, wherein: The image processor is configured to generate the image as a B-mode image.

15. The system according to claim 10, wherein: The tissue comprises liver tissue, and the fat fraction comprises a fat fraction of a liver of the patient.

16. A method for optimized sound velocity settings in an ultrasound medical scanner, the method comprising: Measuring the fat fraction of tissue in the patient's body, and obtaining a calculated amount of the fat fraction by measuring the fat fraction; Setting the beamformer focus distribution based on the amount of fat fraction calculation; Scanning tissue of a patient by an ultrasound medical scanner using a beamformer focal distribution; as well as An image of the tissue is generated based on the scan results.

17. The method according to claim 16, wherein: Measurements include measuring fat fraction via an ultrasound medical scanner.

18. The method according to claim 16, wherein: The setup includes setting the delay or phase distribution of a beamformer of an ultrasound medical scanner.

19. The method according to claim 16, wherein: The setting includes determining the speed of sound in the tissue from the calculated amount of fat fraction, and setting the beamformer focus distribution based on the determined speed of sound.

20. The method according to claim 16, wherein: Scanning includes beamforming using a focus established by a beamformer focus profile.

Images