Ultrasonic imaging device

Abstract

To facilitate an operator to select a transmission frequency suitable for an observation object.SOLUTION: An ultrasonic image processing device includes an image acquisition unit and a display control unit. The image acquisition unit acquires a plurality of ultrasonic images relatively corresponding to a plurality of transmission frequencies. The display control unit controls a display unit to display the plurality of ultrasonic images acquired by the image acquisition unit on the display unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in the present specification and drawings relate to an ultrasonic image processing apparatus. [Background Art]

[0002] In the medical field, ultrasonic diagnostic apparatuses that image the inside of a subject using ultrasonic waves generated by using a plurality of oscillators (or piezoelectric oscillators) of an ultrasonic probe are in use. The ultrasonic diagnostic apparatus causes an ultrasonic probe connected to the ultrasonic diagnostic apparatus to transmit ultrasonic waves into the subject, generates echo signals based on reflected waves, and obtains a desired ultrasonic image through image processing.

[0003] The ultrasonic diagnostic apparatus can perform ultrasonic scanning by the color Doppler method (for example, a blood flow imaging mode for velocity display). In the blood flow imaging mode for velocity display, when a predetermined transmission frequency is selected from among a plurality of transmission frequencies (center frequencies) by an operator, the ultrasonic diagnostic apparatus transmits ultrasonic waves corresponding to the selected transmission frequency and sequentially acquires color Doppler images. Then, the ultrasonic diagnostic apparatus sequentially synthesizes the color Doppler images on a part of the B-mode image and displays the synthesized image on a display 40.

[0004] Here, it is generally known that there are characteristics (trade-offs) as shown in FIG. 13 depending on the transmission frequency of ultrasonic waves. Therefore, it may be difficult for an operator, particularly an operator who has little understanding of the characteristics depending on the transmission frequency, the properties of the observation target, and the surrounding structure of the observation target, to select a transmission frequency suitable for the observation target. [Prior Art Literature] [Patent Literature]

[0005] [Patent Literature 1] Japanese Patent Laid-Open No. 11-276477 [Summary of the Invention] [Problem to be Solved by the Invention]

[0006] One of the problems that the embodiments disclosed herein and in the drawings aim to solve is to facilitate the operator's selection of a transmission frequency suitable for the object being observed. However, the problems that the embodiments disclosed herein and in the drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in each embodiment described later can also be positioned as other problems. [Means for solving the problem]

[0007] The ultrasonic image processing apparatus according to this embodiment comprises an image acquisition unit and a display control unit. The image acquisition unit acquires multiple ultrasonic images corresponding to each of multiple transmission frequencies. The display control unit displays the multiple ultrasonic images acquired by the image acquisition unit on a display unit. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of an ultrasound diagnostic apparatus equipped with an ultrasound image processing device according to an embodiment. [Figure 2] Figure 2 is a block diagram showing an example of the configuration of an ultrasonic transmitting circuit and an ultrasonic receiving circuit provided in an ultrasonic image processing apparatus according to the embodiment. [Figure 3] Figure 3 shows a rate pulse formed from multiple transmission frequencies, which is set in the ultrasonic image processing apparatus according to the embodiment. [Figure 4] Figure 4 shows an example of the display of a selection image by an ultrasonic image processing apparatus according to the embodiment. [Figure 5] Figure 5 is a flowchart illustrating part of the operation of the ultrasonic imaging apparatus according to the embodiment. [Figure 6] Figure 6 is a flowchart illustrating part of the operation of the ultrasonic imaging apparatus according to the embodiment. [Figure 7] Figure 7 is a flowchart illustrating part of the operation of the ultrasonic imaging apparatus according to the embodiment. [Figure 8] Figure 8 shows the region of interest set in the ultrasonic imaging apparatus according to the embodiment. [Figure 9] Figure 9 shows an example of the display of a selection image by an ultrasonic image processing apparatus according to the embodiment. [Figure 10] Figure 10 shows an example of the display of a selection image by an ultrasonic image processing apparatus according to the embodiment. [Figure 11] Figure 11 is a block diagram showing an example of the configuration of an ultrasonic transmitting circuit and an ultrasonic receiving circuit provided in a first modified example of the ultrasonic image processing apparatus according to the embodiment. [Figure 12] Figure 12 is a flowchart showing part of the operation of a second modified example of the ultrasonic image processing apparatus according to the embodiment. [Figure 13] Figure 13 is a table showing the characteristics according to the transmission frequency. [Modes for carrying out the invention]

[0009] The embodiments of the ultrasonic image processing apparatus will be described in detail below with reference to the drawings.

[0010] Figure 1 shows an ultrasound diagnostic apparatus 1 equipped with an ultrasound image processing apparatus 10 according to an embodiment. The ultrasound diagnostic apparatus 1 includes, in addition to the ultrasound image processing apparatus 10, an ultrasound probe 20, an input interface 30, and a display 40. Note that the ultrasound image processing apparatus 10 may also include at least one of the ultrasound probe 20, the input interface 30, and the display 40. In the following description, we will describe the case in which the ultrasound probe 20, the input interface 30, and the display 40 are all provided externally to the ultrasound image processing apparatus 10.

[0011] The ultrasonic image processing device 10 comprises an ultrasonic transmitting circuit 11, an ultrasonic receiving circuit 12, an image memory 13, a network interface 14, a processing circuit 15, and a main memory 16. Circuits 11 and 12 are composed of application-specific integrated circuits (ASICs), etc. However, it is not limited to this case, and all or part of the functions of circuits 11 and 12 may be realized by the processing circuit 15 executing a computer program.

[0012] The ultrasonic transmitting circuit 11 and the ultrasonic receiving circuit 12 control the transmission directivity and reception directivity of ultrasound under the control of the processing circuit 15. While the description will focus on the case where both the ultrasonic transmitting circuit 11 and the ultrasonic receiving circuit 12 are provided in the ultrasonic image processing device 10, at least one of the ultrasonic transmitting circuit 11 and the ultrasonic receiving circuit 12 may be provided in the ultrasonic probe 20, or both the ultrasonic image processing device 10 and the ultrasonic probe 20 may be provided.

[0013] As shown in Figure 2, the ultrasonic transmitting circuit 11 comprises a pulse generation circuit 111, a transmission delay circuit 112, and a pulser circuit 113, and supplies a drive signal to the ultrasonic transducer of the ultrasonic probe 20. The pulse generation circuit 111 repeatedly generates rate pulses to form the transmitted ultrasonic waves at a predetermined repetition frequency (PRF).

[0014] Here, in ultrasonic scanning performed by the color Doppler method (e.g., blood flow image mode for velocity display) for generating a color Doppler image, the pulse generation circuit 111 generates rate pulses corresponding to the selected single transmission frequency under the control of a B-mode processing function 151 and a Doppler processing function 152 described later, thereby acquiring a B-mode image (a background image for synthesizing a color Doppler image) and a color Doppler image. In addition, under the control of the Doppler processing function 152 described later, the pulse generation circuit 111 generates rate pulses including a plurality of transmission frequencies for selection of the transmission frequency. FIG. 3 illustrates an example of such rate pulses. The lower part of FIG. 3(A) shows rate pulses shaped from narrow bands of the three upper transmission frequencies (i.e., center frequencies): low frequency, medium frequency, and high frequency. The lower part of FIG. 3(B) shows rate pulses shaped from a wide band that includes the three upper transmission frequencies. The rate pulses shown in the lower part of FIG. 3(A) or the lower part of FIG. 3(B) enable ultrasonic transmission for three transmission frequencies.

[0015] Returning to the description of FIG. 2, the transmission delay circuit 112 applies a delay time for each piezoelectric vibrator, which is required to focus the ultrasonic waves generated from the ultrasonic probe 20 into a beam shape and determine transmission directivity, to each rate pulse generated by the pulse generation circuit 111. The transmission direction or the transmission delay time that determines the transmission direction is stored in the main memory 16 and referenced during transmission. The pulser circuit 113 applies drive signals (drive pulses) to a plurality of ultrasonic transducers provided in the ultrasonic probe 20 at a timing based on the rate pulse. By changing the delay time applied to each rate pulse via the transmission delay circuit 112, the transmission direction from the piezoelectric vibrator surface can be arbitrarily adjusted.

[0016] The ultrasonic transmission circuit 11 has a function capable of instantaneously changing the transmission frequency, transmission drive voltage, and the like in order to execute a predetermined scan sequence based on an instruction from the processing circuit 18. In particular, the function of changing the transmission drive voltage is realized by, for example, a linear amplifier type transmission circuit capable of instantaneously switching the value, or a mechanism that electrically switches between a plurality of power supply units.

[0017] As shown in Figure 2, the ultrasonic reception circuit 12 includes an amplifier circuit 121, an A / D (Analog to Digital) conversion circuit 122, a demodulation circuit 123, and a beamformer 124. The ultrasonic reception circuit 12 receives echo signals received by ultrasonic transducers, performs various types of processing on the echo signals, and generates echo data. Here, the ultrasonic image processing apparatus 10 has two methods for generating an ultrasonic image: a first method in which delay addition is performed on an RF (Radio Frequency) signal that is a reception signal, then orthogonal detection (demodulation) is performed to convert the signal into an IQ signal composed of an I (In-phase) signal and a Q (Quadrature-phase) signal to generate an ultrasonic image; and a second method in which orthogonal detection is performed on the RF signal to convert it to IQ baseband, then delay addition is performed to generate an ultrasonic image. The former is also called RF beamforming. The latter is also called IQ beamforming. Figure 2 shows a configuration example of IQ beamforming. RF beamforming will be described later with reference to Figure 11.

[0018] In IQ beamforming, echoes are thinned (decimated) according to the depth to be displayed on the screen, which reduces the amount of data processed by beamforming, enables generation of a large number of beams, and thus has the feature of increasing the number of parallel simultaneous receptions of beams. Whether echoes are thinned and the thinning rate are determined depending on the type of the ultrasonic probe 20, the ultrasonic mode, the display depth of the ultrasonic image, the zoom magnification of the ultrasonic image, and the like.

[0019] The amplifier circuit 121 amplifies the reflected wave signal received by the ultrasonic probe 20 for each channel and performs gain correction processing. At this time, the amplifier circuit 121 changes the gain value according to, for example, a predetermined time response. The time response of the gain applied to the reception signal in the amplifier circuit 121 is stored in the main memory 16. The A / D conversion circuit 122 converts the gain-corrected reflected wave signal into a digital signal.

[0020] The demodulation circuit 123 includes a number of demodulation circuits corresponding to multiple transmission frequencies, as described later, for example, three demodulation circuits corresponding to three transmission frequencies (first demodulation circuit D1, second demodulation circuit D2, and third demodulation circuit D3). When the pulse generation circuit 111 generates a rate pulse corresponding to a single transmission frequency, one of the demodulation circuits D1, D2, or D3, for example, the first demodulation circuit D1, demodulates the digital signal output of the A / D conversion circuit 122, thereby converting the digital signal into a baseband IQ signal.

[0021] On the other hand, when the pulse generation circuit 111 generates a rate pulse containing multiple transmission frequencies, the demodulation circuits D1, D2, and D3 each extract a single frequency from the signal containing the three transmission frequencies, which is the output of the A / D conversion circuit 122, and demodulate the digital signal, thereby converting the digital signal into a baseband IQ signal. For example, the first demodulation circuit D1 extracts a low frequency from the signal containing the three transmission frequencies and demodulates the digital signal, thereby converting the digital signal into a baseband IQ signal. The second demodulation circuit D2 extracts a medium frequency from the signal containing the three transmission frequencies and demodulates the digital signal, thereby converting the digital signal into a baseband IQ signal. The third demodulation circuit D3 extracts a high frequency from the signal containing the three transmission frequencies and demodulates the digital signal, thereby converting the digital signal into a baseband IQ signal.

[0022] The beamformer 124 imparts a delay time necessary to determine the receiving directivity to the IQ signal, which is the output of the demodulation circuit 123, and adds the delayed IQ signal. The processing by the beamformer 124 generates a received signal in which the reflected component from the direction corresponding to the receiving directivity is emphasized.

[0023] The beamformer 124 includes a number of beamformers corresponding to multiple transmission frequencies, as described later, for example, three beamformers corresponding to three transmission frequencies (first beamformer B1, second beamformer B2, and third beamformer B3). When the pulse generation circuit 111 generates a rate pulse corresponding to a single transmission frequency, one of the beamformers B1, B2, or B3, for example the first beamformer B1, adds the IQ signal, which is the output of the first demodulation circuit D1, with the delay time necessary to determine the receiving directivity.

[0024] On the other hand, when the pulse generation circuit 111 generates rate pulses containing multiple transmission frequencies, the beamformers B1, B2, and B3 add the IQ signals, which are the outputs of the demodulation circuits D1, D2, and D3, respectively, after adding a delay time. For example, the first beamformer B1 adds the low-frequency IQ signal, which is the output of the first demodulation circuit D1, after adding a delay time. The second beamformer B2 adds the medium-frequency IQ signal, which is the output of the second demodulation circuit D2, after adding a delay time. The third beamformer B3 adds the high-frequency IQ signal, which is the output of the third demodulation circuit D3, after adding a delay time.

[0025] Returning to the explanation of Figure 1, the image memory 13 has, for example, a magnetic or optical recording medium, or a recording medium that can be read by a processor such as a semiconductor memory. The image memory 13 stores multiple ultrasound images under the control of the processing circuit 15. Note that the image memory 13 is an example of a storage unit.

[0026] The network interface 14 implements various information and communication protocols depending on the network configuration. The network interface 14 connects the ultrasound diagnostic device 1 to other devices such as the external medical image management device 2 and the medical image processing device 3, according to these protocols. This connection can be an electrical connection via an electronic network. Here, "electronic network" refers to all information and communication networks utilizing telecommunications technology, including wireless / wired hospital backbone LANs (Local Area Networks) and the Internet, as well as telephone communication networks, fiber optic communication networks, cable communication networks, and satellite communication networks.

[0027] Furthermore, the network interface 14 may implement various protocols for contactless wireless communication. In this case, the ultrasonic image processing device 10 can directly transmit and receive data with, for example, the ultrasonic probe 20 without using a network. Note that the network interface 14 is an example of a network connection unit.

[0028] The processing circuit 15 refers to a dedicated or general-purpose CPU (Central Processing Unit), MPU (Micro Processor unit), or GPU (Graphics Processing Unit), as well as an ASIC and a programmable logic device. Examples of programmable logic devices include simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs).

[0029] Furthermore, the processing circuit 15 may be composed of a single circuit or a combination of multiple independent circuit elements. In the latter case, the main memory 16 may be provided individually for each circuit element, or a single main memory 16 may store programs corresponding to the functions of multiple circuit elements. Note that the processing circuit 15 is just one example of a processing unit.

[0030] The main memory 16 is composed of semiconductor memory elements such as RAM (random access memory) and flash memory, a hard disk, an optical disc, etc. The main memory 16 may also be composed of portable media such as USB (universal serial bus) memory and DVD (digital video disc). The main memory 16 stores various processing programs used in the processing circuit 15 (including application programs and the OS (operating system), etc.) and data necessary for program execution. The OS may also include a GUI (graphical user interface) that makes extensive use of graphics to display information on the display 40 for the operator and allows basic operations to be performed via the input interface 30. Note that the main memory 16 is just one example of a storage unit.

[0031] The ultrasonic probe 20 is equipped with multiple tiny transducers (piezoelectric elements) on its front surface and transmits and receives ultrasonic waves over the area including the area to be scanned. Each transducer is an electroacoustic conversion element, which converts electrical pulses into ultrasonic pulses during transmission and converts reflected waves into electrical signals (received signals) during reception. The ultrasonic probe 20 is small and lightweight and is connected to the ultrasonic image processing device 10 via a cable (or wireless communication).

[0032] Ultrasound probes 20 can be classified into linear, convex, and sector types based on their scanning method. Furthermore, ultrasound probes 20 can be classified into 1D array probes, where multiple transducers are arranged one-dimensionally (1D) in the azimuth direction (i.e., the long axis direction), and 2D array probes, where multiple transducers are arranged two-dimensionally (2D) in both the azimuth and elevation directions (i.e., the short axis direction). Note that 1D array probes include probes with a small number of transducers arranged in the elevation direction.

[0033] Here, when a 3D scan, or volume scan, is performed, a 2D array probe equipped with scanning methods such as linear, convex, and sector types is used as the ultrasonic probe 20. Alternatively, when a volume scan is performed, a 1D probe equipped with scanning methods such as linear, convex, and sector types, and a mechanism that mechanically oscillates in the elevation direction, is used as the ultrasonic probe 20. The latter probe is also called a mechanical 4D probe.

[0034] The input interface 30 includes an input device that can be operated by the user and an input circuit that receives signals from the input device. The input device can be a trackball, a switch, a mouse, a keyboard, a touchpad that allows input by touching the operating surface, a touchscreen that integrates a display screen and a touchpad, a non-contact input device using an optical sensor, or an audio input device. When the user operates the input device, the input circuit generates a signal corresponding to that operation and outputs it to the processing circuit 15. Note that the input interface 30 is just one example of an input section.

[0035] The display 40 is composed of a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display. The display 40 displays various information according to the control of the processing circuit 15. Note that the display 40 is just one example of a display unit.

[0036] Figure 1 also shows the medical image management device 2 and the medical image processing device 3, which are external devices to the ultrasound diagnostic device 1. The medical image management device 2 is, for example, a DICOM (Digital Imaging and Communications in Medicine) server and is connected to devices such as the ultrasound diagnostic device 1 via a network N to enable data transmission and reception. The medical image management device 2 manages the ultrasound images generated by the ultrasound diagnostic device 1 as DICOM files.

[0037] The medical image processing device 3 is connected to equipment such as the ultrasound diagnostic device 1 and the medical image management device 2 via a network N, enabling data transmission and reception. Examples of the medical image processing device 3 include a workstation that performs various image processing on ultrasound images generated by the ultrasound diagnostic device 1, and a portable information processing terminal such as a tablet. The medical image processing device 3 may be an offline device that can read ultrasound images generated by the ultrasound diagnostic device 1 via a portable storage medium.

[0038] Next, the functions of the ultrasonic image processing device 10 will be explained using Figure 1.

[0039] The processing circuit 15 reads and executes a computer program stored in the main memory 16 or in the memory within the processing circuit 15 to realize the B-mode processing function 151, the Doppler processing function 152, the image generation function 153, the display control function 154, and the reception function 155. The B-mode processing function 151, the Doppler processing function 152, and the image generation function 153 constitute the acquisition function F. The following explanation will use the case where functions 151 to 155 are realized by a computer program as an example, but all or part of functions 151 to 155 may be provided as functions of circuits such as ASICs in the ultrasound image processing device 10.

[0040] The image acquisition function F includes the function of controlling the ultrasonic transmitting circuit 11 and the ultrasonic receiving circuit 12, etc., to perform an ultrasonic scan using the ultrasonic probe 20 and acquire multiple ultrasonic images (e.g., color Doppler images) corresponding to each of multiple transmission frequencies. The image acquisition function F also includes the function of controlling the ultrasonic transmitting circuit 11 and the ultrasonic receiving circuit 12, etc., to perform an ultrasonic scan using the ultrasonic probe 20 and acquire an ultrasonic image (e.g., B-mode image) corresponding to a single transmission frequency.

[0041] The B-mode processing function 151 controls the ultrasonic transmitting circuit 11 and the ultrasonic receiving circuit 12, receives echo data from the ultrasonic receiving circuit 12, and performs logarithmic amplification and envelope detection processing to generate data (2D or 3D data) in which the signal strength is represented by brightness. This data is generally called B-mode data.

[0042] The Doppler processing function 152 is a function that generates data (Doppler information) by performing frequency analysis on the received signal received from the ultrasonic receiving circuit 12, thereby extracting motion information based on the Doppler effect of moving objects within the region of interest (ROI) set in the scan area. The generated Doppler information is stored in the RAW data memory (not shown) as Doppler RAW data (also referred to as Doppler data) on a two-dimensional ultrasonic scan line.

[0043] Specifically, the Doppler processing function 152 estimates, for example, the average velocity, mean variance, and average power value as motion information of a moving object at each of multiple sample points, and generates Doppler data showing the estimated motion information. The moving object is, for example, blood flow, tissue such as the heart wall, or contrast agent. The Doppler processing function 152 estimates, for example, the average velocity of blood flow, the variance of blood flow velocity, and the power value of the blood flow signal as motion information of blood flow (i.e., blood flow information) at each of multiple sample points, and generates Doppler data showing the estimated blood flow information.

[0044] Furthermore, the Doppler processing function 152 can perform a color Doppler method, also known as Color Flow Mapping (CFM). In the CFM method, ultrasound is transmitted and received multiple times on multiple scan lines. In the CFM method, for example, by applying an MTI (Moving Target Indicator) filter to the data sequence at the same location, signals originating from stationary or slow-moving tissue (clutter signals) are suppressed, and signals originating from blood flow are extracted. The CFM method then uses the extracted blood flow signals to estimate blood flow information such as blood flow velocity, blood flow dispersion, and blood flow power. The image generation function 153, described later, generates a color Doppler image as an ultrasound image, for example, by displaying the estimated distribution of blood flow information in two dimensions. Note that color display means displaying the distribution of blood flow information corresponding to a predetermined color code, and grayscale is also included in color display.

[0045] There are various types of blood flow imaging modes depending on the desired clinical information. Generally, there are blood flow imaging modes that display the direction and average velocity of blood flow, and blood flow imaging modes that display the power of the blood flow signal.

[0046] The former, the blood flow imaging mode for velocity display, is a mode that displays colors corresponding to the Doppler shift frequency depending on the direction of blood flow and the average velocity of blood flow. For example, in the blood flow imaging mode for velocity display, flow toward the ultrasound probe 20 is represented by red tones, and flow away from it is represented by blue tones, and the difference in velocity between them is represented by the difference in hue. The blood flow imaging mode for velocity display is sometimes called the color Doppler mode or the Color Doppler Imaging (CDI) mode.

[0047] The latter, the power-displaying blood flow video mode, is a mode that represents the power of the blood flow signal, for example, by changes in the hue, brightness (luminosity), or saturation of red tones. The power-displaying blood flow video mode is sometimes called the Power Doppler (PD) mode. Because the power-displaying blood flow video mode can depict blood flow with higher sensitivity compared to the speed-displaying blood flow video mode, it may also be called the high-sensitivity blood flow video mode.

[0048] In addition to the CDI and PD modes mentioned above, there are also low-velocity blood flow imaging modes specifically designed for visualizing low flow velocities, and high-resolution blood flow imaging modes.

[0049] The image generation function 153 generates an ultrasound image as image data, expressed within a predetermined brightness range, based on the echo signal received by the ultrasound probe 20. For example, the image generation function 153 generates a B-mode image as an ultrasound image, representing the intensity of reflected waves in brightness from the two-dimensional B-mode data generated by the B-mode processing function 151. The image generation function 153 also generates a color Doppler image as an ultrasound image, representing motion information, such as an average velocity image, dispersion image, power image, or a combination of these images, from the two-dimensional Doppler data generated by the Doppler processing function 152.

[0050] Here, the image generation function 153 generally converts the scan line signal sequence of the ultrasonic scan into a scan line signal sequence of a video format, such as that used in televisions (scan conversion), and generates an ultrasonic image for display. Specifically, the image generation function 153 generates an ultrasonic image for display by performing coordinate transformations according to the ultrasonic scanning pattern of the ultrasonic probe 20. In addition to scan conversion, the image generation function 153 also performs various image processing tasks, such as image processing that regenerates an average brightness image using multiple image frames after scan conversion (smoothing process), and image processing that uses a differential filter within the image (edge ​​enhancement process). Furthermore, the image generation function 153 synthesizes various parameter text information, scales, body marks, etc., onto the ultrasonic image.

[0051] In other words, B-mode data and Doppler data are ultrasound images before scan conversion processing, while the data generated by the image generation function 153 is the ultrasound image for display after scan conversion processing. B-mode data and Doppler data are also called raw data. The image generation function 153 generates a two-dimensional ultrasound image for display from the two-dimensional ultrasound image before scan conversion processing.

[0052] The display control function 154 includes a function to display multiple ultrasound images corresponding to multiple transmission frequencies as selection images on the display 40. The display control function 154 also includes a function to display an ultrasound image corresponding to a single transmission frequency as an observation image on the display 40. Specifically, the display control function 154 displays multiple composite images on the display 40 by sequentially combining multiple color Doppler images (multiple selection images) corresponding to multiple transmission frequencies into a portion of the B-mode image, or by sequentially combining a color Doppler image (observation image) corresponding to a single transmission frequency into a portion of the B-mode image. An example of the display of selection images on the display 40 is shown in Figure 4.

[0053] As shown in Figure 4, the display control function 154 displays three composite images on the display 40, each containing multiple selection images, for example, three color Doppler images, combined with a B-mode image. Furthermore, each selection image in the region of interest R is displayed sequentially (updated). Additionally, if aliasing occurs in any of the selection images, the display control function 154 can change the flow velocity scale to obtain accurate color display.

[0054] Note that the display of the three selection images is not limited to this parallel display. For example, the display control function 154 may display the three selection images one by one sequentially. In that case, the display control function 154 will synthesize and display a low-frequency color Doppler image in the region of interest R of the B-mode image, perform ultrasound transmission and reception after a certain period of time to synthesize and display a medium-frequency color Doppler image in the region of interest R, perform ultrasound transmission and reception after a certain period of time to synthesize and display a high-frequency color Doppler image in the region of interest R.

[0055] The reception function 155 includes a function to receive an operation to select a predetermined ultrasound image from multiple ultrasound images corresponding to multiple transmission frequencies, which are displayed by the display control function 154. Note that the reception function 155 is not an essential component of the processing circuit 15.

[0056] Next, the operation of functions 151 to 155 will be explained using Figures 5 to 10. In the flowcharts shown in Figures 5 to 7, the symbols with numbers attached to "ST" indicate each step.

[0057] The ultrasound image processing device 10 receives examination order information from, for example, an examination request device (not shown) such as HIS (Hospital Information Systems), and then receives an instruction to start an ultrasound scan using the color Doppler method (e.g., blood flow image mode for velocity display). When the operator places the tip of the ultrasound probe 20 on the patient's body surface, directed at the object of observation (e.g., the abdominal aorta), the B-mode processing function 161 controls the ultrasound transmission circuit 11 and the ultrasound reception circuit 12, etc., to start an ultrasound scan using the ultrasound probe 20 and acquires a B-mode image as a background image for the color Doppler image (step ST1). Based on the operator's operation via the input interface 30, the Doppler processing function 152 sets a region of interest R (shown in Figure 8) on the B-mode image acquired in step ST1, where the distribution of blood flow information is to be displayed (step ST2).

[0058] The Doppler processing function 152 determines whether or not it is in transmission frequency selection mode based on the operator's operation via the input interface 30 (step ST3). If the determination in step ST3 is YES, i.e., it is in transmission frequency selection mode, the Doppler processing function 152 controls the pulse generation circuit 111 of the ultrasonic transmission circuit 11 to transmit a rate pulse (shown in Figure 3) containing multiple transmission frequencies (step ST4).

[0059] The image generation function 153 generates a color Doppler image in the region of interest R corresponding to low frequencies based on the output of the first beamformer B1 (shown in Figure 2) of the ultrasonic receiving circuit 12 (step ST5). The display control function 154 then displays a composite image by combining the color Doppler image (selection image) corresponding to low frequencies with the region of interest R set in step ST2 of the B-mode image (step ST6). The image generation function 153 also generates a color Doppler image in the region of interest R corresponding to medium frequencies based on the output of the second beamformer B2 (shown in Figure 2) of the ultrasonic receiving circuit 12 (step ST7). The display control function 154 then displays a composite image by combining the color Doppler image (selection image) corresponding to medium frequencies with the region of interest R set in step ST2 of the B-mode image (step ST8). The image generation function 153 also generates a color Doppler image in the region of interest R corresponding to high frequencies based on the output of the third beamformer B3 (shown in Figure 2) of the ultrasonic receiving circuit 12 (step ST9). The display control function 154 then displays a composite image (step ST10) in which a color Doppler image corresponding to a high frequency (selection image) is superimposed on the region of interest R set in step ST2 of the B-mode image. The display of the selection images in steps ST6, ST8, and ST10 is shown in Figure 4. The three selection images are each generated based on three single-frequency received signals extracted from the received signal obtained by rate pulses containing three transmission frequencies.

[0060] The processing order of the steps ST5 and ST6, the steps ST7 and ST8, and the steps ST9 and ST10 is not restricted, and they may be performed simultaneously. Furthermore, the display control function 154 enables the selection of any of the images displayed by steps ST6, ST8, and ST10. Specifically, the display control function 154 may be configured to select an image by detecting a press (touch) of any of the three selection images (or three composite images), or by detecting a click of any of the three selection images, or by detecting a click of a "Select" button located near any of the three selection images.

[0061] The reception function 155 determines, based on the operator's operation via the input interface 30, whether or not it has received a selection of one of the three color Doppler images, i.e., one of the transmission frequencies (step ST11). When the three color Doppler images are displayed in a way that allows selection, the operator can select the desired color Doppler image by referring to the three color Doppler images (see Figure 9). Once the operator has selected one of the three color Doppler images, the transmission frequency corresponding to the selected color Doppler image is selected as the desired transmission frequency.

[0062] Alternatively, the system may be configured so that the operator selects one of the three color Doppler images of the sizes shown in Figure 9, or it may be configured so that the operator selects from three enlarged images (shown in Figure 10) in which each of the three color Doppler images is enlarged around the region of interest R. In this case, when the reception function 155 receives a press of the "Enlarge" button shown in Figure 9, the display control function 114 displays the three enlarged images (shown in Figure 10) on the display 40, in which each of the three color Doppler images (i.e., the region of interest R) is enlarged. In this enlarged display, it is preferable to also display the original image (e.g., low frequency) alongside the enlarged image so that the operator can grasp the entire scan area. Furthermore, when the reception function 155 receives a press of the "Reduce" button shown in Figure 10, the display control function 114 displays the three enlarged images (shown in Figure 9) on the display 40 (returning them to their original size).

[0063] Returning to the explanation in Figure 5, if the decision in step ST11 is YES, that is, if the selection of any transmission frequency is accepted, the Doppler processing function 152 controls the pulse generation circuit 111 of the ultrasonic transmission circuit 11 to transmit a rate pulse corresponding to the transmission frequency selected in step ST11 (step ST12 in Figure 6).

[0064] The image generation function 153 generates a color Doppler image in the region of interest R corresponding to the transmission frequency selected in step ST11 (step ST13). Then, the display control function 154 displays a composite image as an observation image, which is a B-mode image with the color Doppler image corresponding to the selected transmission frequency superimposed on the region of interest R set in step ST2 (step ST14). The operator makes a diagnosis of the patient's condition while observing the observation image displayed in step ST14.

[0065] The Doppler processing function 152 determines whether or not to terminate the ultrasound scan based on the operator's operation via the input interface 30 (step ST15). If the determination in step ST15 is YES, i.e., to terminate the ultrasound scan, the ultrasound image processing device 10 terminates the ultrasound scan.

[0066] On the other hand, if the decision in step ST15 is NO, i.e., if it is determined that the ultrasound scan should not be terminated, the Doppler processing function 152 transmits a rate pulse in the next frame corresponding to the transmission frequency selected in step ST11 (step ST12).

[0067] Furthermore, if the determination in step ST3 shown in Figure 5 is NO, that is, if it is determined that it is not in transmission frequency selection mode, the process proceeds to Figure 7 (conventional technology flow), where the reception function 155 accepts the selection of a transmission frequency based on the operator's operation via the input interface 30 (step ST21). The Doppler processing function 152 controls the pulse generation circuit 111 of the ultrasonic transmission circuit 11 to transmit a rate pulse corresponding to the transmission frequency selected in step ST21 (step ST22).

[0068] The image generation function 153 generates a color Doppler image in the region of interest R corresponding to the transmission frequency selected in step ST21 (step ST23). Then, the display control function 154 displays a composite image as an observation image, which is a B-mode image with the color Doppler image corresponding to the transmission frequency selected in step ST21 superimposed on the region of interest R set in step ST2 (step ST24). The operator makes a diagnosis of the patient's subject of observation while observing the observation image displayed in step ST24.

[0069] The Doppler processing function 152 determines whether or not to terminate the ultrasound scan based on the operator's operation via the input interface 30 (step ST25). If the determination in step ST25 is YES, i.e., to terminate the ultrasound scan, the ultrasound image processing device 10 terminates the ultrasound scan.

[0070] On the other hand, if the decision in step ST25 is NO, that is, if it is determined that the ultrasound scan will not be terminated, the reception function 155 determines whether or not the selection of a new transmission frequency has been accepted (step ST26). If the decision in step ST26 is YES, that is, if it is determined that the selection of a new transmission frequency has been accepted, the Doppler processing function 152 changes the transmission frequency (step ST27) and transmits a rate pulse corresponding to the selected new transmission frequency in the next frame (step ST22). On the other hand, if the decision in step ST26 is NO, that is, if it is determined that the selection of a new transmission frequency has not been accepted, the Doppler processing function 152 transmits a rate pulse corresponding to the same transmission frequency as the previous frame in the next frame (step ST22).

[0071] According to the flow shown in Figure 7, the operator will have to repeatedly change the transmission frequency (steps ST26, ST27) while referring to the display of "one observation image" (step ST24), which will result in prolonged examination times, decreased examination efficiency, and increased burden on the patient.

[0072] In step ST11 of Figure 5, the case where the reception function 155 accepts the selection of one of the three transmission frequencies was described, but it is not limited to that case. For example, the reception function 155 may accept the selection of any two of the three transmission frequencies. In that case, the Doppler processing function 152 generates a rate pulse containing the two selected transmission frequencies, and the display control function 154 displays two selection images. The reception function 155 then accepts the selection of one of the two transmission frequencies. Also, in steps ST4 to ST11 of Figure 5, the case where the selection image generated by the rate pulse containing multiple transmission frequencies is a color Doppler image was described, but it is not limited to that case. For example, the selection image may be a B-mode image.

[0073] Furthermore, the Doppler processing function 152 can select three transmission frequencies for the selection image (and similarly for the single transmission frequency for the observation image) according to the location of the region of interest. For example, if the region of interest is relatively close to the body surface, the moving object is a low-velocity flow, so the Doppler processing function 152 can select three transmission frequencies on the higher frequency side. On the other hand, if the region of interest is relatively deep from the body surface, the moving object is a high-velocity flow, so the Doppler processing function 152 can select three transmission frequencies on the lower frequency side. The Doppler processing function 152 can also select three transmission frequencies for the selection image (and similarly for the single transmission frequency for the observation image) according to the velocity range of the highest flow velocity range within the region of interest. In addition, the Doppler processing function 152 can set three transmission frequencies for the selection image (and similarly for the single transmission frequency for the observation image) using machine learning. For example, deep learning using multi-layer neural networks such as CNNs (Convolutional Neural Networks) and CDBNs (Convolutional Deep Belief Networks) is used as machine learning. The Doppler processing function 152 constructs a trained model based on the location (or speed range) of the region of interest and the transmission frequency adopted at that location. By inputting the location of the region of interest in this test into the trained model, it can output several dominant transmission frequencies.

[0074] According to the ultrasound image processing device 10, multiple color Doppler images corresponding to multiple transmission frequencies can be presented to the operator, making it easier for the operator to select a transmission frequency.

[0075] (First variation) Figure 2 illustrates the case where the beamforming method is IQ beamforming, but the beamforming method may also be RF beamforming. This case will be explained using Figure 11 as the first modified example.

[0076] Figure 11 shows the ultrasonic receiving circuit 12A and Doppler processing function 152A in the case of RF beamforming. The ultrasonic receiving circuit 12A comprises an amplifier circuit 121, an A / D conversion circuit 122, and a beamformer 124A, and receives the echo signal received by the ultrasonic transducer and performs various processing on this echo signal to generate echo data. In Figure 11, the same reference numerals are used for components that are the same as in Figure 2, and their descriptions are omitted.

[0077] The beamformer 124A imparts a delay time necessary to determine the receiving directivity to the digital signal output from the A / D conversion circuit 122. The beamformer 124A then adds the digital signal to which the delay time has been applied. The processing by the beamformer 124A generates a received signal in which the reflected component from the direction corresponding to the receiving directivity is emphasized.

[0078] The Doppler processing function 152A converts a digital signal into a baseband IQ signal by extracting a single frequency from the signal containing the three transmission frequencies, which is the output of the beamformer 124A, and demodulating the digital signal. For example, the Doppler processing function 152A converts a digital signal into a baseband IQ signal by extracting a low frequency from the signal containing the three transmission frequencies and demodulating the digital signal, converts a digital signal into a baseband IQ signal by extracting a medium frequency and demodulating the digital signal, and converts a digital signal into a baseband IQ signal by extracting a high frequency and demodulating the digital signal. Then, the Doppler processing function 152A generates Doppler information within the region of interest set in the scan area by frequency analysis of the IQ signal.

[0079] According to the first modified version of the ultrasonic imaging apparatus 10, similar to the effects described above, the operator can easily select the transmission frequency.

[0080] (Second variation) The above describes a configuration in which one of several selection images is selected, but it is also possible to configure the system to change the combination of selection images, that is, the combination of transmission frequencies. This case will be explained using Figure 12 as a second modified example. In Figure 12, the same reference numerals are used for the same steps as in Figure 5, and their explanations are omitted.

[0081] After step ST10, the reception function 155 determines whether or not it has accepted a change in the transmission frequency combination based on the operator's operation via the input interface 30 (step ST31). If the determination in step ST31 is YES, that is, if it is determined that a change in the transmission frequency combination has been accepted, the Doppler processing function 152 changes the transmission frequency combination (step ST32) and controls the pulse generation circuit 111 of the ultrasonic transmission circuit 11 to transmit a rate pulse containing multiple transmission frequencies corresponding to the changed combination (step ST4).

[0082] On the other hand, if the determination in step ST31 is NO, that is, if it is determined that the change in the transmission frequency combination has not been accepted, the reception function 155 determines whether or not the selection of one of the three selection images, that is, one of the transmission frequencies, has been accepted, based on the operation by the operator via the input interface 30 (step ST11).

[0083] Thus, according to steps ST31 and ST32, the operator can refer to the selection images corresponding to the first, second, and third transmission frequencies, and perform a change operation if they wish to refer to selection images for other transmission frequencies. The operator can then refer to the selection images corresponding to a fourth, fifth, and sixth transmission frequency instead of the initial three transmission frequencies and select one of them. The priority order between the initially set first to third transmission frequencies and the modified fourth to sixth transmission frequencies may be set from the location and speed range of the region of interest, as described above, or from a trained model.

[0084] According to the second modified version of the ultrasound image processing device 10, in addition to the effects described above, the combination of multiple selection images corresponding to multiple transmission frequencies can be changed, so that the operator can select a desired transmission frequency from a variety of selection images.

[0085] According to at least one embodiment described above, the operator can easily select a transmission frequency suitable for the object being observed.

[0086] Note that the image acquisition function F is an example of an image acquisition unit. The B-mode processing function 151 is an example of a B-mode processing unit. The Doppler processing functions 152 and 152A are examples of Doppler processing units. The image generation function 153 is an example of an image generation unit. The display control function 154 is an example of a display control unit. The reception function 155 is an example of a reception unit.

[0087] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, modifications, combinations of embodiments, and combinations of embodiments with one or more modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0088] 1… Ultrasound diagnostic equipment 10… Ultrasonic imaging device 11… Ultrasonic transmission circuit 12… Ultrasonic receiving circuit 15…Processing circuit 20… Ultrasound probe 30…Input Interface 40…Display F...Image acquisition function 151...B-mode processing function 152, 152A... Doppler processing function 153…Image generation function 154…Display control function 155... Reception function

Claims

1. An image acquisition unit that acquires multiple ultrasound images corresponding to each of multiple transmission frequencies, A display control unit that displays the plurality of ultrasonic images on a display unit as selection images for selecting a transmission frequency, Equipped with, The image acquisition unit, The ultrasonic transmitting unit is controlled to generate rate pulses containing the plurality of transmitting frequencies for the selection of the transmitting frequency. An ultrasonic image processing apparatus for acquiring multiple ultrasonic images corresponding to each frequency from low to high frequencies, which are generated by extracting single-frequency received signals corresponding to each of the multiple transmission frequencies from a single received signal obtained by the rate pulse.

2. The image acquisition unit acquires multiple color Doppler images as the multiple ultrasound images. The ultrasonic image processing apparatus according to claim 1.

3. The display control unit displays the plurality of ultrasonic images side by side on the display unit. The ultrasonic image processing apparatus according to claim 1.

4. The display control unit displays a plurality of composite images obtained by combining the plurality of color Doppler images with a B-mode image. The ultrasonic image processing apparatus according to claim 2.

5. The display control unit displays a plurality of composite images on the display unit, which are obtained by combining the plurality of color Doppler images within the region of interest set in the B-mode image. The ultrasonic image processing apparatus according to claim 4.

6. A receiving unit that receives an operation to select a predetermined ultrasound image from the aforementioned plurality of ultrasound images, Equipped with, The image acquisition unit acquires an ultrasonic image corresponding to a single transmission frequency corresponding to a predetermined ultrasonic image selected by the reception unit, The display control unit displays an ultrasonic image corresponding to the single transmission frequency on the display unit. The ultrasonic image processing apparatus according to claim 1.

7. A receiving unit that accepts an operation to change multiple transmission frequencies corresponding to the multiple ultrasound images, Equipped with, The image acquisition unit acquires multiple ultrasonic images corresponding to each of the multiple transmission frequencies modified by the reception unit. The display control unit displays a plurality of ultrasonic images on the display unit, each corresponding to a plurality of transmission frequencies modified by the reception unit. The ultrasonic image processing apparatus according to claim 1.

8. The image acquisition unit sets the plurality of transmission frequencies according to the location of the region of interest for which the plurality of ultrasound images are combined. The ultrasonic image processing apparatus according to claim 1.

9. The image acquisition unit acquires an ultrasound image corresponding to a single transmission frequency corresponding to a predetermined ultrasound image selected from the plurality of ultrasound images based on the location of the region of interest, The display control unit displays an ultrasonic image corresponding to the single transmission frequency on the display unit. The ultrasonic image processing apparatus according to claim 1.

Images