JP7291534B2 - Analysis equipment and ultrasonic diagnostic equipment - Google Patents

Description

An embodiment of the present invention relates to an analysis device and an ultrasonic diagnostic device.

2. Description of the Related Art In the medical field, an ultrasonic diagnostic apparatus is used that images the inside of a subject using ultrasonic waves generated using a plurality of transducers (piezoelectric transducers) of an ultrasonic probe. An ultrasonic diagnostic apparatus transmits ultrasonic waves into a subject from an ultrasonic probe connected to the ultrasonic diagnostic apparatus, generates received signals based on reflected waves, and obtains a desired ultrasonic image by image processing.

In ultrasonic diagnostic equipment, after delay addition of RF (Radio Frequency) signals, which are received signals, quadrature detection (demodulation) is performed to convert them into IQ signals consisting of I (In-phase) signals and Q (Quadrature-phase) signals. and generating an ultrasonic image, and a method of generating an ultrasonic image by performing quadrature detection of the RF signal and converting it into an IQ baseband and then performing delay addition. The former is also called RF beamforming. The latter is also called IQ beamforming. Functions for improving the image quality of ultrasonic images in IQ beamforming include a function for controlling the gain of an amplifier, a function for controlling a reception delay curve of a delay control circuit, and the like.

JP 2016-002379 A

The problem to be solved by the present invention is to provide an ultrasound image with high visibility of blood flow.

An ultrasonic diagnostic apparatus according to an embodiment includes a principal component analysis section, a signal processing section, an adjustment amount calculation section, and a display control section. The principal component analysis unit performs principal component analysis on the received ultrasonic signal. The signal processor extracts imaging components from the received signal using the result of the principal component analysis. The adjustment amount calculator calculates an adjustment amount of the signal intensity of the signal to be visualized based on the information obtained by the principal component analysis. The display control unit causes the display unit to display the ultrasound image with the signal intensity adjusted by the adjustment amount.

1 is a schematic diagram showing a configuration of an ultrasonic diagnostic apparatus according to an embodiment; FIG. FIG. 2 is a block diagram showing the configuration of a receiving circuit provided in a transmitting/receiving circuit of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 3 is a diagram for explaining clutter artifacts when principal component analysis is not performed; FIG. 4 is a diagram for explaining clutter artifacts when principal component analysis is performed; FIG. 5 is a diagram for explaining clutter artifacts when principal component analysis is performed in the ultrasonic diagnostic apparatus according to the embodiment; FIG. 6 is a diagram showing, as a flowchart, the operation of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 7 is a diagram for explaining clutter artifacts when principal component analysis is performed and signal strength is adjusted in the ultrasonic diagnostic apparatus according to the embodiment; FIG. 8 is a diagram showing, as a flowchart, the operation of the first modification of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 9 is a diagram for explaining clutter artifacts when principal component analysis is performed in the first modification of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 10 is a diagram showing, as a flowchart, the operation of the second modification of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 11 is a diagram showing, as a flowchart, the operation of the third modification of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 12 is a diagram showing, as a flowchart, the operation of the fourth modification of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 13 is a diagram showing a display example indicating that the signal strength has been greatly changed in the fourth modification of the ultrasonic diagnostic apparatus according to the embodiment; FIG. 14 is a schematic diagram showing the configuration of the analysis device according to the embodiment; FIG. 15 is a block diagram showing functions of the analysis device according to the embodiment;

Hereinafter, embodiments of an analysis apparatus and an ultrasonic diagnostic apparatus will be described in detail with reference to the drawings.
1. ultrasound diagnostic equipment

FIG. 1 is a schematic diagram showing the configuration of an ultrasonic diagnostic apparatus according to an embodiment.

FIG. 1 shows an ultrasonic diagnostic apparatus 10 according to an embodiment. FIG. 1 also shows an ultrasound probe 20 , an input interface 30 and a display 40 . An apparatus obtained by adding at least one of the ultrasonic probe 20, the input interface 30, and the display 40 to the ultrasonic diagnostic apparatus 10 may also be called an ultrasonic diagnostic apparatus. In the following description, the case where the ultrasonic probe 20, the input interface 30, and the display 40 are all provided outside the ultrasonic diagnostic apparatus 10 will be described.

The ultrasonic diagnostic apparatus 10 includes a transmission/reception circuit 11, a B-mode processing circuit 12, a Doppler processing circuit 13, an image generation circuit 14, an image memory 15, a display control circuit 16, a network interface 17, and a processing circuit 18. and a main memory 19 . The circuits 11 to 14 are configured by an application specific integrated circuit (ASIC) or the like. However, it is not limited to that case, and all or part of the functions of the circuits 11 to 14 may be implemented by the processing circuit 18 executing a program.

The transmitting/receiving circuit 11 has a transmitting circuit (not shown) and a receiving circuit 111 (shown in FIG. 2). The transmission/reception circuit 11 controls transmission directivity and reception directivity in transmission/reception of ultrasonic waves under the control of the processing circuit 18 . Although a case where the transmission/reception circuit 11 is provided in the ultrasonic diagnostic apparatus 10 will be described, the transmission/reception circuit 11 may be provided in the ultrasonic probe 20, or may be provided in both the ultrasonic diagnostic apparatus 10 and the ultrasonic probe 20. may be provided. The transmitting/receiving circuit 11 is an example of a transmitting/receiving section.

The transmission circuit has a pulse generator circuit, a transmission delay circuit, a pulsar circuit, etc., and supplies drive signals to the ultrasonic transducers. A pulse generation circuit repeatedly generates rate pulses for forming a transmitted ultrasound wave at a predetermined rate frequency. The transmission delay circuit sets the delay time for each piezoelectric transducer necessary to focus the ultrasonic waves generated from the ultrasonic transducers of the ultrasonic probe 20 into a beam shape and determine the transmission directivity. given for each rate pulse that occurs. Also, the pulsar circuit applies a drive pulse to the ultrasonic transducer at a timing based on the rate pulse. The transmission delay circuit arbitrarily adjusts the transmission direction of the ultrasonic beam transmitted from the piezoelectric transducer surface by changing the delay time given to each rate pulse.

The receiving circuit 111 receives the received signal received by the ultrasonic transducer, performs various processes on the received signal, and generates echo data. Note that the configuration of the receiving circuit 111 will be described later with reference to FIG.

The B-mode processing circuit 12 receives the echo data from the receiving circuit under the control of the processing circuit 18, performs logarithmic amplification, envelope detection processing, etc., and converts data ( 2D or 3D data). This data is commonly referred to as B-mode data. Note that the B-mode processing circuit 12 is an example of a B-mode processing section.

Note that the B-mode processing circuit 12 can change the frequency band to be visualized by changing the detection frequency through filter processing. By using the filtering function of the B-mode processing circuit 12, harmonic imaging such as contrast harmonic imaging (CHI) and tissue harmonic imaging (THI) can be performed.

That is, the B-mode processing circuit 12 converts reflected wave data (harmonic wave data or divided frequency data) of harmonic components with the contrast medium (microbubbles, bubbles) as a reflection source from the reflected wave data of the subject injected with the contrast medium. ) and the reflected wave data (fundamental wave data) of the fundamental wave component whose reflection source is the tissue in the subject. The B-mode processing circuit 12 can also generate B-mode data for generating contrast-enhanced image data from reflected wave data (received signals) of harmonic components, and can also generate reflected wave data (received signals) of fundamental wave components. signal) can be used to generate B-mode data for generating fundamental image data.

Further, in THI by using the filter processing function of the B-mode processing circuit 12, it is possible to separate harmonic data or frequency division data, which are reflected wave data (received signal) of harmonic components, from the reflected wave data of the subject. can. Then, the B-mode processing circuit 12 can generate B-mode data for generating tissue image data from which noise components are removed from reflected wave data (received signals) of harmonic components.

Furthermore, when performing harmonic imaging of CHI or THI, the B-mode processing circuit 12 can extract harmonic components by a method different from the above-described method using filtering. Harmonic imaging employs an imaging method called an AMPM method, which is a combination of an amplitude modulation (AM) method, a phase modulation (PM) method, and an AM method and a PM method. In the AM method, PM method, and AMPM method, ultrasonic waves with different amplitudes and phases are transmitted multiple times to the same scanning line.

Thereby, the transmitting/receiving circuit 11 generates and outputs a plurality of reflected wave data (received signals) for each scanning line. Then, the B-mode processing circuit 12 extracts harmonic components by subjecting a plurality of reflected wave data (received signals) of each scanning line to addition/subtraction processing according to the modulation method. Then, the B-mode processing circuit 12 performs envelope detection processing and the like on the reflected wave data (received signal) of the harmonic component to generate B-mode data.

For example, when the PM method is performed, the transmitting/receiving circuit 11 transmits ultrasonic waves of the same amplitude with inverted phase polarities, such as (−1, 1), in each scan according to the scan sequence set by the processing circuit 18. Send the line twice. Then, the transmitting/receiving circuit 11 generates a received signal by transmitting "-1" and a received signal by transmitting "1", and the B-mode processing circuit 12 adds these two received signals. As a result, the fundamental wave component is removed, and a signal in which the second harmonic wave component remains mainly is generated. Then, the B-mode processing circuit 12 performs envelope detection processing and the like on this signal to generate B-mode data of THI and B-mode data of CHI.

Alternatively, for example, in THI, a method of imaging using a second harmonic component and a difference tone component included in a received signal has been put into practical use. In the imaging method using the difference tone component, for example, a synthesized waveform obtained by synthesizing a first fundamental wave with a center frequency of "f1" and a second fundamental wave with a center frequency of "f2" larger than "f1" is transmitted. Ultrasound is transmitted from the ultrasound probe 20 . This composite waveform is a waveform obtained by synthesizing the waveforms of the first fundamental wave and the waveform of the second fundamental wave whose phases are adjusted so that a difference tone component having the same polarity as the second harmonic component is generated. is. The transmitting/receiving circuit 11 transmits, for example, twice the transmission ultrasonic wave of the composite waveform while reversing the phase. In such a case, for example, the B-mode processing circuit 12 adds the two received signals to remove the fundamental wave component and extracts the harmonic component in which the difference tone component and the secondary harmonic component remain mainly. Envelope detection processing, etc. are performed.

Under the control of the processing circuit 18, the Doppler processing circuit 13 frequency-analyzes the velocity information from the echo data from the receiving circuit, and extracts data (2 2D or 3D data). This data is commonly called Doppler data. Here, the moving body is, for example, blood flow, tissue such as a heart wall, and a contrast agent. Note that the Doppler processing circuit 13 is an example of a Doppler processing unit.

Under the control of the processing circuit 18, the image generation circuit 14 generates, as image data, an ultrasound image expressed in a predetermined luminance range based on the received signal received by the ultrasound probe 20. FIG. For example, the image generation circuit 14 generates, as an ultrasound image, a B-mode image representing the intensity of the reflected wave by luminance from the two-dimensional B-mode data generated by the B-mode processing circuit 12 . In addition, the image generation circuit 14 converts the two-dimensional Doppler data generated by the Doppler processing circuit 13 into an ultrasound image to generate an average velocity image, a variance image, a power image, or a combination of these images. Generate color Doppler images. Note that the image generation circuit 14 is an example of an image generation unit.

Here, the image generation circuit 14 generally converts (scan converts) a scanning line signal train of ultrasonic scanning into a scanning line signal train of a video format typified by a television or the like, and converts the ultrasonic wave for display. Generate image data. Specifically, the image generating circuit 14 performs coordinate conversion according to the scanning mode of the ultrasonic waves by the ultrasonic probe 20 to generate ultrasonic image data for display. In addition to the scan conversion, the image generation circuit 14 performs various types of image processing, such as image processing (smoothing processing) for regenerating a brightness average value image using a plurality of image frames after scan conversion. , and performs image processing (edge enhancement processing) using a differential filter in the image. Further, the image generation circuit 14 synthesizes character information of various parameters, scales, body marks, etc. with the ultrasonic image data.

That is, the B-mode data and Doppler data are ultrasound image data before scan conversion processing, and the data generated by the image generation circuit 14 are ultrasound image data for display after scan conversion processing. B-mode data and Doppler data are also called raw data. The image generating circuit 14 generates two-dimensional ultrasonic image data for display from the two-dimensional ultrasonic image data before scan conversion processing.

Furthermore, the image generation circuit 14 performs coordinate transformation on the three-dimensional B-mode data generated by the B-mode processing circuit 12 to generate three-dimensional B-mode image data. The image generation circuit 14 also performs coordinate transformation on the three-dimensional Doppler data generated by the Doppler processing circuit 13 to generate three-dimensional Doppler image data. The image generation circuit 14 generates “three-dimensional B-mode image data or three-dimensional Doppler image data” as “three-dimensional ultrasound image data (volume data)”.

Furthermore, the image generation circuit 14 performs rendering processing on the volume data in order to generate various two-dimensional image data for displaying the volume data on the display 40 . As rendering processing, the image generation circuit 14 performs, for example, a cross-sectional reconstruction method (MPR: Multi Planer Reconstruction) to generate MPR image data from volume data. The image generating circuit 14 also performs volume rendering (VR) processing for generating two-dimensional image data reflecting three-dimensional information as rendering processing, for example.

The image memory 15 includes a two-dimensional memory, which is a memory having a plurality of memory cells in two axial directions per frame and having memory cells for a plurality of frames. A two-dimensional memory serving as the image memory 15 stores, as two-dimensional image data, one or more frames of ultrasound images generated by the image generating circuit 14 under the control of the processing circuit 18 . Note that the image memory 15 is an example of a storage unit.

Under the control of the processing circuit 18, the image generation circuit 14 performs three-dimensional reconstruction by performing interpolation processing as necessary on the ultrasonic images arranged in the two-dimensional memory as the image memory 15, thereby obtaining an image. An ultrasonic image is generated as volume data in a three-dimensional memory as the memory 15 . A known technique is used as the interpolation processing method.

The image memory 15 may also include a three-dimensional memory, which is a memory having a plurality of memory cells in three axial directions (X-axis, Y-axis, and Z-axis directions). The three-dimensional memory as the image memory 15 stores the ultrasound image generated by the image generation circuit 14 under the control of the processing circuit 18 as volume data.

The display control circuit 16 includes a GPU (Graphics Processing Unit), a VRAM (Video RAM), and the like. Under the control of the processing circuit 18 , the display control circuit 16 adjusts the signal intensity of the ultrasonic image (for example, live image) requested by the processing circuit 18 to display on the display 40 . The signal strength is indicated by an adjustment amount calculation circuit 59, which will be described later. Note that the display control circuit 16 is an example of a display control unit.

The network interface 17 implements various information communication protocols according to the form of the network. The network interface 17 connects the ultrasonic diagnostic apparatus 10 with other devices such as the external medical image management apparatus 60 and the medical image processing apparatus 70 according to these various protocols. An electrical connection or the like via an electronic network can be applied to this connection. Here, the term "electronic network" refers to all information communication networks using telecommunication technology, including wireless/wired LANs (Local Area Networks) of hospital backbones, Internet networks, telephone communication networks, and optical fiber communication networks. , cable communication networks and satellite communication networks.

Network interface 17 may also implement various protocols for contactless wireless communication. In this case, the ultrasonic diagnostic apparatus 10 can directly transmit/receive data to/from the ultrasonic probe 20 without going through a network, for example. Note that the network interface 17 is an example of a network connection unit.

The processing circuit 18 means a processor such as a dedicated or general-purpose CPU (central processing unit), MPU (micro processor unit), or GPU (Graphics Processing Unit), as well as an ASIC, a programmable logic device, or the like. Examples of programmable logic devices include simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs). mentioned.

Also, the processing circuit 18 may be composed of a single circuit, or may be composed of a combination of a plurality of independent circuit elements. In the latter case, the main memory 19 may be provided separately for each circuit element, or a single main memory 19 may store programs corresponding to functions of a plurality of circuit elements. Note that the processing circuit 18 is an example of a processing unit.

The main memory 19 is composed of a semiconductor memory device such as a RAM (random access memory), a flash memory, a hard disk, an optical disk, or the like. The main memory 19 may be composed of portable media such as USB (universal serial bus) memory and DVD (digital video disk). The main memory 19 stores various processing programs (including application programs, an OS (operating system), etc.) used in the processing circuit 18, and data necessary for executing the programs. In addition, the OS can 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 through the input interface 30 . Note that the main memory 19 is an example of a storage unit.

The ultrasonic probe 20 has a plurality of minute transducers (piezoelectric elements) on its front surface, and transmits and receives ultrasonic waves to and from a region including a scan target, for example, a region including a lumen. Each transducer is an electroacoustic transducer, and has a function of converting an electric pulse into an ultrasonic pulse during transmission and converting a reflected wave into an electric signal (receiving signal) during reception. The ultrasonic probe 20 is configured to be compact and lightweight, and is connected to the ultrasonic diagnostic apparatus 10 via a cable (or wireless communication).

The ultrasonic probe 20 is classified into a linear type, a convex type, a sector type, and the like depending on the scanning method. In addition, the ultrasonic probe 20 has a 1D array probe in which a plurality of transducers are arranged one-dimensionally (1D) in the azimuth direction, and a two-dimensional (2D) array probe in the azimuth and elevation directions. ) can be classified into a 2D array probe in which a plurality of transducers are arranged. Note that the 1D array probe includes a probe in which a small number of transducers are arranged in the elevation direction.

Here, when a 3D scan, that is, a volume scan is performed, a 2D array probe having scanning methods such as a linear type, a convex type, and a sector type is used as the ultrasonic probe 20 . Alternatively, when volume scanning is performed, a 1D probe having a linear, convex, sector, or other scanning method and a mechanism for mechanically swinging in the elevation direction is used as the ultrasonic probe 20. be done. The latter probes are also called mecha 4D probes.

The input interface 30 includes an input device operable by an operator and an input circuit for inputting signals from the input device. Input devices include trackballs, switches, mice, keyboards, touch pads that perform input operations by touching the operation surface, touch screens that integrate display screens and touch pads, non-contact input devices using optical sensors, and a voice input device or the like. When the operator operates the input device, the input circuit generates a signal according to the operation and outputs it to the processing circuit 18 .

Also, the input interface 30 can further include an adjustment switch for adjusting the frequency characteristics of the reception filter, which will be described later. Note that the input interface 30 is an example of an input unit.

The display 40 is configured by 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 under the control of the processing circuit 18 . Note that the display 40 is an example of a display unit.

1 also shows a medical image management apparatus 60 and a medical image processing apparatus 70, which are external devices of the ultrasonic diagnostic apparatus 10. As shown in FIG. The medical image management apparatus 60 is, for example, a DICOM (Digital Imaging and Communications in Medicine) server, and is connected to equipment such as the ultrasonic diagnostic apparatus 10 via the network N so as to be able to transmit and receive data. The medical image management apparatus 60 manages medical images such as ultrasonic images generated by the ultrasonic diagnostic apparatus 10 as DICOM files.

The medical image processing apparatus 70 is connected to devices such as the ultrasonic diagnostic apparatus 10 and the medical image management apparatus 60 via the network N so as to be able to transmit and receive data. Examples of the medical image processing apparatus 70 include a workstation that performs various types of image processing on an ultrasonic image generated by the ultrasonic diagnostic apparatus 10, a portable information processing terminal such as a tablet terminal, and the like. Note that the medical image processing apparatus 70 may be an off-line apparatus, and may be an apparatus capable of reading an ultrasonic image generated by the ultrasonic diagnostic apparatus 10 via a portable storage medium.

Next, the concept of the configuration and function of the receiving circuit provided in the transmitting/receiving circuit 11 will be described with reference to FIG.

FIG. 2 is a block diagram showing the configuration of a receiving circuit provided in the transmitting/receiving circuit 11. As shown in FIG.

FIG. 2 shows a receiving circuit 111 provided in the transmitting/receiving circuit 11. As shown in FIG. The receiving circuit 111 includes an amplifier 51, an A/D (Analog to Digital) conversion circuit 52, a quadrature detection circuit 53, a delay control circuit 54, an addition circuit 55, a filter processing circuit 56, and a principal component analysis circuit 57. , a signal processing circuit 58 , and an adjustment amount calculation circuit 59 .

The amplifier 51 has a function of amplifying the signal received from the ultrasonic probe 20 for each channel and performing gain correction processing under the control of the processing circuit 18 . The amplifier 51 can improve the image quality of the ultrasonic image by controlling the gain.

The A/D conversion circuit 52 has a function of A/D converting the gain-corrected reception signal output from the amplifier 51 for each channel under the control of the processing circuit 18 .

The quadrature detection circuit 53 has a function of quadrature-detecting an RF signal, which is a received signal, and converting it into an IQ signal composed of an I signal and a Q signal for each channel.

The delay control circuit 54, under the control of the processing circuit 18, has a function of giving the IQ signal, which is the output of the A/D conversion circuit 52, a delay time necessary for determining the reception directivity for each channel. The delay control circuit 54 can improve the image quality of the ultrasonic image by controlling the reception delay curve given to the IQ signal.

The adder circuit 55 performs phase rotation and weighting control (apodization) for each channel on the IQ signal output from the delay control circuit 54, performs addition processing of the obtained IQ signals, and generates beam data of the IQ signals. have a function. The addition processing of the adder circuit 55 emphasizes the reflection component from the direction corresponding to the reception directivity of the received signal.

Under the control of the processing circuit 18, the filter processing circuit 56 has a function of applying an arbitrary complex receive filter to the IQ signal output from the adder circuit 55, and converts the IQ signal to which the complex receive filter has been applied into a B-mode signal. It also has a function of outputting to the processing circuit 12 and the Doppler processing circuit 13 . Note that the filter processing circuit 56 is an example of a filter processing unit.

The principal component analysis circuit 57 has a function of performing principal component analysis of the received ultrasonic signal under the control of the processing circuit 18 . The principal component analysis circuit 57 performs eigenvalue expansion or singular value decomposition of the ultrasonic reception signal. Note that the principal component analysis circuit 57 is an example of a principal component analysis section.

The signal processing circuit 58 has a function of extracting imaging components from the received signal using the result of principal component analysis by the principal component analysis circuit 57 under the control of the processing circuit 18 . The signal processing circuit 58 can specify the tissue (clutter) to be removed from the ultrasonic image based on the result of the principal component analysis, and change the filter characteristics according to the Doppler frequency (proper order) of the tissue. , the tissue component contained in the received signal can be suppressed and the blood flow component can be extracted.

FIG. 3 is a diagram for explaining clutter artifacts when principal component analysis is performed. Specifically, FIG. 3A shows a schematic diagram of the eigenvalue distribution when the eigenorder to be visualized is fixed and the subject does not pulsate. The eigen order to visualize is the left dark part of the distribution. FIG. 3B shows a schematic diagram of the eigenvalue distribution when the eigenorder to be visualized is fixed and the subject has pulsation. The eigen order to visualize is the left dark part of the distribution. FIG. 3(C) is a diagram showing an example of an image after filtering in the case of FIG. 3(A). FIG. 3(D) is a diagram showing an example of an image after filtering in the case of FIG. 3(B).

As shown in FIG. 3B, when the eigenorder is fixed and the object has pulsation, as shown in FIG. occurs (e.g. in the thick white line). This is derived from the fact that there is a correlation between the amount of displacement of the clutter source and the amount of amplitude and phase fluctuations in the received signal. , artifacts can occur in frames where the clutter source moves a lot. In order to suppress such artifacts, it is effective to adaptively change the eigen-order to be visualized.

FIG. 4 is a diagram for explaining clutter artifacts when principal component analysis is performed. Specifically, FIG. 4A shows a schematic diagram of the eigenvalue distribution when the eigenorder to be visualized varies and the subject does not pulsate. The eigen order to visualize is the left dark part of the distribution. FIG. 4B shows a schematic diagram of the eigenvalue distribution when the eigenorder to be visualized varies and when the subject has a pulsation. The eigen order to visualize is the left dark part of the distribution. FIG. 4(C) is a diagram showing an example of an image after filtering in the case of FIG. 4(A). FIG. 4(D) is a diagram showing an example of an image after filtering in the case of FIG. 4(B).

As shown in FIG. 4(A), when the eigen order is a variable value and the subject does not pulsate, the image changes less as shown in FIG. 4(C) compared to FIG. 3(C). is not seen.

On the other hand, as shown in FIG. 4(B), when the characteristic order is a variable value and the subject has pulsation, as shown in FIG. 4(D), compared with FIG. 3(D), clutter artifact is suppressed (e.g. within the thick white line). However, even if the eigen-order to be visualized is adaptively varied, the influence of pulsation cannot be suppressed. This is because the blood flow signal and the pulsatile clutter signal exist in the same proper order. For example, if clutter to be suppressed is aliased, clutter will occur no matter which eigenorder is visualized. Moreover, even when the amount of statistical information of the signal used for eigenvalue decomposition is insufficient, the blood flow signal and the pulsatile clutter signal cannot be accurately separated in the eigen order, and they are made to exist in the same eigen order. Such artifacts flicker (flash) along with the pulsation in real-time observation, and reduce the visibility of the blood flow signal, which can be said to be a serious practical problem.

FIG. 5 is a diagram for explaining clutter artifacts when principal component analysis is performed. Specifically, FIG. 5A is a diagram showing an example of an image after filtering when the eigenorder to be visualized varies and the subject does not pulsate. FIG. 5B is a diagram showing an example of an image after filtering when the eigenorder to be visualized varies and when the subject has pulsations.

As shown in FIG. 5(A), when the eigen-order to be visualized is appropriately varied, there is almost no flickering area due to the influence of pulsation. On the other hand, as shown in FIG. 5B, even if the eigen-order to be visualized is appropriately varied, there is a blinking area due to the influence of pulsation (for example, inside the thick white line).

Therefore, as shown in FIG. 2, the receiving circuit 111 provided in the transmitting/receiving circuit 11 has an adjustment amount calculation circuit 59 . Accordingly, the ultrasonic diagnostic apparatus 10 adaptively determines the imaging signal strength so as to suppress clutter artifacts.

The adjustment amount calculation circuit 59 has a function of calculating the adjustment amount of the signal intensity of the signal to be visualized based on the information obtained by the principal component analysis by the principal component analysis circuit 57 under the control of the processing circuit 18 . The adjustment amount calculation circuit 59 outputs the signal intensity adjustment amount to the display control circuit 16 . Note that the adjustment amount calculation circuit 59 is an example of an adjustment amount calculation unit.

Next, operations of the ultrasonic diagnostic apparatus 10 will be described.

FIG. 6 is a diagram showing the operation of the ultrasonic diagnostic apparatus 10 as a flowchart. In FIG. 6, numerals attached to "ST" indicate respective steps of the flow chart.

The processing circuit 18 of the ultrasonic diagnostic apparatus 10 controls the transmitting/receiving circuit 11 and the like to start ultrasonic scanning using the ultrasonic probe 20 (step ST1).

The principal component analysis circuit 57 acquires the IQ signal for one frame, which is the output of the addition circuit 55 (step ST2). The principal component analysis circuit 57 performs eigenvalue expansion of the IQ signal obtained in step ST2 (step ST3). Either eigenvalue expansion or singular value decomposition may be performed as principal component analysis.

The signal processing circuit 58 calculates the contribution rate of each unique order obtained in step ST3 (step ST4). The signal processing circuit 58 calculates the integrated contribution rate up to each proper order based on the contribution rate of each proper order calculated in step ST4 (step ST5). The signal processing circuit 58 compares the integrated contribution rate calculated for each unique order in step ST5 with the threshold, obtains the unique order when the threshold is exceeded for the first time, and determines the unique order (step ST6). Note that the threshold is set in advance.

The filter processing circuit 56 performs filter processing based on the intrinsic order determined in step ST6 (step ST7), and outputs the processed signal to the B-mode processing circuit 12 or the Doppler processing circuit 13. FIG. On the other hand, the adjustment amount calculation circuit 59 calculates the signal strength adjustment amount (gain) based on the characteristic order determined in step ST6 (step ST8), and outputs the signal strength adjustment amount to the display control circuit 16. For example, the adjustment amount calculation circuit 59 obtains the signal strength adjustment amount using the following equation (1).
Adjustment amount of signal strength = reference value × intrinsic order to be visualized / normalized value (1)

The display control circuit 16 adjusts the signal intensity according to the signal intensity adjustment amount calculated by the adjustment amount calculation circuit 59, and then causes the display 40 to display the ultrasonic image (step ST9).

FIG. 7 is a diagram for explaining clutter artifacts when principal component analysis is performed and signal strength is adjusted. FIG. 7A is a diagram showing an example of an image when the signal intensity is adjusted with respect to FIG. 5A. FIG. 7B is a diagram showing an example of an image when the signal intensity is adjusted with respect to FIG. 5B.

As shown in FIG. 7(A), in the case of a subject with no pulsation, there is almost no change in the image compared with FIG. 5(A). On the other hand, as shown in FIG. 7B, in the case of a subject with pulsation, the brightness (brightness) of the image is suppressed compared to FIG. can be suppressed (e.g. within the thick white line).

Returning to the description of FIG. 6, the principal component analysis circuit 57 determines whether or not there is a received signal of the next frame (step ST10). If the determination in step ST10 is YES, that is, if it is determined that there is no received signal for the next frame, the ultrasonic diagnostic apparatus 10 ends its operation. On the other hand, if the determination in step ST10 is NO, that is, if it is determined that there is a received signal for the next frame, the principal component analysis circuit 57 converts the IQ signal for the next one frame, which is the output of the addition circuit 55, into acquire (step ST2).

Note that FIG. 6 has been described assuming that the amount of signal strength adjustment is obtained for each frame, but the present invention is not limited to this case. For example, the signal strength adjustment amount may be obtained only for the first frame, and the adjustment amount may be used for all subsequent frames, or the signal strength adjustment amount may be obtained only for frames at regular intervals and the most recent frame may be used. The requested adjustment may be used.

According to the ultrasonic diagnostic apparatus 10, even in the case of a subject with pulsation, by appropriately adjusting the signal intensity, an ultrasonic image in which pulsatile clutter artifacts are visually reduced is provided. be able to. This improves the visibility of blood flow on an ultrasound image for an operator such as a doctor.

2. First Modification The method of calculating the signal intensity adjustment amount is not limited to the one described above. It is also possible to calculate the adjustment amount of the signal strength of the region by assuming that the signal from the region greatly affected by the pulsation has a large phase variation in the time direction and that the clutter component is dominant in the received signal. .

FIG. 8 is a diagram showing the operation of the first modification of the ultrasonic diagnostic apparatus 10 as a flowchart. In FIG. 8, numerals attached to "ST" indicate respective steps of the flow chart.

8, the same steps as those in FIG. 6 are given the same reference numerals, and the description thereof is omitted.

The adjustment amount calculation circuit 59 calculates the complex coherency in the time direction, calculates the adjustment amount of the signal intensity based on the complex coherency (step ST18), and outputs the adjustment amount of the signal intensity to the display control circuit 16. For example, the adjustment amount calculation circuit 59 obtains the signal strength adjustment amount using the following equation (2). For example, if the complex coherency in the time direction is relatively large, it can be assumed to be a clutter component such as a blood vessel wall, and if the complex coherency in the time direction is relatively small, it can be assumed to be a blood flow component.
Signal strength adjustment amount = reciprocal of complex correlation function amplitude in time direction (2)

FIG. 9 is a diagram for explaining clutter artifacts when principal component analysis is performed. Specifically, FIG. 9A shows an example of an image after filtering (without signal intensity adjustment) when the eigenorder to be visualized varies and when the subject does not pulsate. It is a figure which shows. FIG. 9B is a diagram showing an example of an image after filtering (without signal intensity adjustment) when the eigenorder to be visualized varies and when the subject has pulsations. . FIG. 9(C) is a diagram showing an example of an image when the signal intensity is adjusted with respect to FIG. 9(A). FIG. 9(D) is a diagram showing an example of an image when the signal intensity is adjusted with respect to FIG. 9(B).

As shown in FIG. 9(C), in the case of a subject with no pulsation, there is almost no change in the image compared to FIG. 9(A). On the other hand, as shown in FIG. 9D, in the case of a subject with pulsation, the brightness (brightness) of the image is suppressed compared to FIG. can be suppressed.

According to the first modified example of the ultrasonic diagnostic apparatus 10, the same effects as those described above can be obtained.

3. Second Modification The method of calculating the signal strength adjustment amount is not limited to the above-described method. It is determined from a biosignal such as an electrocardiogram signal or a phonocardiogram signal that the frame corresponds to a cardiac phase in which the influence of pulsation is large, and the following determination specific to imaging and calculation of an adjustment amount for the signal intensity are performed. good too.

FIG. 10 is a diagram showing the operation of the second modification of the ultrasonic diagnostic apparatus 10 as a flowchart. In FIG. 10, numerals attached to "ST" indicate respective steps of the flow chart.

10, the same steps as those in FIG. 6 are given the same reference numerals, and the description thereof is omitted.

The adjustment amount calculation circuit 59 determines whether or not the frame corresponds to a cardiac phase that is greatly affected by the pulsation, based on biomedical signals such as an electrocardiogram and a phonocardiogram (step ST21). If the determination in step ST21 is YES, that is, if the frame is a frame corresponding to a cardiac phase that is greatly affected by pulsation, the process proceeds to step ST8.

On the other hand, if the determination in step ST21 is NO, that is, if it is determined that the frame is not a frame corresponding to a cardiac phase that is greatly affected by the pulsation, the display control circuit 16 does not adjust the signal intensity, A sound wave image is displayed on the display 40 (step ST22), and the process proceeds to step ST10.

Note that the technical idea of the second modification of the ultrasonic diagnostic apparatus 10 can also be applied to the second modification of the ultrasonic diagnostic apparatus 10 .

According to the second modified example of the ultrasonic diagnostic apparatus 10, it is possible to obtain effects equivalent to those described above, and to selectively adjust the signal intensity only for ultrasonic images in which flickering is likely to occur.

4. Third Modification In the above-described embodiments and modifications, if the amount of signal strength adjustment becomes excessive, noise components such as thermal noise and quantization noise may be visualized. Therefore, the third modification of the ultrasonic diagnostic apparatus 10 prevents the noise component (white noise) from being visualized by adjusting the signal intensity.

FIG. 11 is a diagram showing the operation of the third modification of the ultrasonic diagnostic apparatus 10 as a flowchart. In FIG. 11, numerals attached to "ST" indicate respective steps of the flow chart.

11, the same steps as those in FIG. 6 are given the same reference numerals, and the description thereof is omitted.

The adjustment amount calculation circuit 59 determines whether or not the adjustment amount calculated in step ST8 is equal to or less than the threshold (step ST31). If the determination in step ST31 is YES, that is, if it is determined that the adjustment amount is equal to or less than the threshold, the process proceeds to step ST9.

On the other hand, if the determination in step ST31 is NO, that is, if it is determined that the adjustment amount is greater than the threshold, the display control circuit 16 adjusts the signal intensity according to the threshold for the adjustment amount of the signal intensity, and then displays the ultrasonic image. is displayed on the display 40 (step ST32), and the process proceeds to step ST10.

Note that the technical idea of the third modification of the ultrasonic diagnostic apparatus 10 can also be applied to the second and third modifications of the ultrasonic diagnostic apparatus 10 .

According to the third modified example of the ultrasonic diagnostic apparatus 10, it is possible to obtain the same effects as those described above and prevent excessive adjustment of the signal strength.

5. Fourth Modification There is a possibility that the blood flow signal intensity will increase or decrease due to the adjustment amount calculation described above. It is conceivable that the operator may be confused as to whether the increase or decrease in signal intensity is due to the action of the living body or the action of calculating the adjustment amount described above. Therefore, the fourth modification of the ultrasonic diagnostic apparatus 10 notifies the operator that the strength of the blood flow signal is being increased or decreased in order to improve usability.

FIG. 12 is a diagram showing the operation of the fourth modification of the ultrasonic diagnostic apparatus 10 as a flowchart. In FIG. 12, numerals attached to "ST" indicate respective steps of the flow chart.

12, the same steps as in FIG. 6 are assigned the same reference numerals, and the description thereof is omitted.

The adjustment amount calculation circuit 59 determines whether or not the adjustment amount calculated in step ST8 is equal to or less than the threshold (step ST41). If the determination in step ST41 is YES, that is, if it is determined that the adjustment amount is equal to or less than the threshold, the process proceeds to step ST9.

On the other hand, if NO in step ST41, that is, if it is determined that the adjustment amount is greater than the threshold, the display control circuit 16 notifies that the signal intensity has been significantly changed (step ST42), and step ST9. proceed to For example, in step ST42, the display control circuit 16 causes the display 40 to display that the signal intensity has changed significantly. FIG. 13 is a diagram showing a display example indicating that the signal strength has been changed significantly.

The technical idea of the fourth modification of the ultrasonic diagnostic apparatus 10 can also be applied to the second to fourth modifications of the ultrasonic diagnostic apparatus 10. FIG.

According to the fourth modification of the ultrasonic diagnostic apparatus 10, the same effects as those described above can be obtained, and usability can be improved.

6. Analysis Apparatus The calculation and application of the signal strength described above can also be performed by an analysis apparatus other than the ultrasonic diagnostic apparatus 10, for example, a medical image processing apparatus.

FIG. 14 is a schematic diagram showing the configuration of the medical image processing apparatus according to the embodiment.

FIG. 14 shows a medical image processing apparatus 70 according to an embodiment. The medical image processing apparatus 70 is a medical image management apparatus (image server), workstation, interpretation terminal, etc., and is provided on a medical image system connected via a network. Note that the medical image processing apparatus 70 may be an off-line apparatus.

The medical image processing apparatus 70 includes a processing circuit 71 , a memory 72 , an input interface 73 , a display control circuit 74 , a display 75 and a network interface 76 . The processing circuit 71, the memory 72, the input interface 73, the display control circuit 74, the display 75, and the network interface 76 are the processing circuit 18, the main memory 19, the input interface 30, and the display shown in FIG. Since the control circuit 16, the display 40, and the network interface 17 have the same configuration, their description is omitted.

Next, functions of the medical image processing apparatus 70 will be described.

FIG. 15 is a block diagram showing functions of the medical image processing apparatus 70. As shown in FIG.

The processing circuit 71 implements an acquisition function 711 , a principal component analysis function 712 , a signal processing function 713 , and an adjustment amount calculation function 714 by executing programs stored in the memory 72 . Note that all or part of the functions 711 to 714 are not limited to being realized by executing the program of the medical image processing apparatus 70, but may be provided as a circuit such as an ASIC in the medical image processing apparatus 70. There may be.

The acquisition function 711 includes a function of acquiring ultrasonic image data and a received signal output from the addition circuit 55 from the medical image management apparatus 60 or the ultrasonic diagnostic apparatus 10 via the network interface 76 . Note that the acquisition function 711 is an example of an image acquisition unit.

The principal component analysis function 712, the signal processing function 713, and the adjustment amount calculation function 714 are functions equivalent to the functions of the principal component analysis circuit 57, the signal processing circuit 58, and the adjustment amount calculation circuit 59 shown in FIG. , so the description is omitted. The principal component analysis function 712 is an example of a principal component analysis section, the signal processing function 713 is an example of a signal processing section, and the adjustment amount calculation function 714 is an example of an adjustment amount calculation section. The adjustment amount calculation function 714 controls the display control circuit 74 to adjust the signal intensity according to the signal intensity adjustment amount calculated by the adjustment amount calculation function 714, and then displays the ultrasonic image acquired by the acquisition function 711. display on the display 75.

According to the analysis device such as the medical image processing device 70, even in the case of a subject with pulsation, by appropriately adjusting the signal intensity, ultrasonic waves with visually reduced pulsatile clutter artifacts can be obtained. Images can be provided. This improves the visibility of blood flow on an ultrasound image for an operator such as a doctor. Moreover, there is also an effect equivalent to the effect shown in the above-mentioned modified example.

According to at least one embodiment described above, it is possible to provide an ultrasound image with high visibility of blood flow.

It should be noted that although several embodiments of the invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

10 Ultrasound diagnostic device 11 Transmission/reception circuit 16 Display control circuit 57 Principal component analysis circuit 58 Signal processing circuit 59 Adjustment amount calculation circuit 70 Analysis device (medical image processing device)
71 processing circuit 711 acquisition function 712 principal component analysis function 713 signal processing function 714 adjustment amount calculation function

Claims (9)

a principal component analysis unit that performs principal component analysis of a received ultrasonic signal;
a signal processing unit that extracts imaging components from the received signal using the result of the principal component analysis;
an adjustment amount calculation unit that calculates an adjustment amount of the signal intensity of the signal to be visualized based on the information obtained by the principal component analysis;
a display control unit that causes a display unit to display an ultrasound image whose signal intensity has been adjusted by the adjustment amount;
with
The signal processing unit is
Calculate the integrated contribution rate up to each proper order,
Comparing the integrated contribution rate calculated for each unique order with a threshold to obtain the unique order when the threshold is exceeded for the first time, determining the unique order to be visualized,
The adjustment amount calculation unit
calculating the adjustment amount based on the natural order to be visualized;
analysis equipment. a principal component analysis unit that performs principal component analysis of a received ultrasonic signal;
a signal processing unit that extracts imaging components from the received signal using the result of the principal component analysis;
an adjustment amount calculation unit that calculates the coherency of the received signal in the time direction and calculates an adjustment amount of the signal intensity of the signal to be visualized based on the coherency;
a display control unit that causes a display unit to display an ultrasound image whose signal intensity has been adjusted by the adjustment amount;
Analysis device comprising . The adjustment amount calculation unit determines a frame for adjusting the signal strength based on biosignal information.
The analysis device according to claim 1 or 2 . The biological signal is an electrocardiogram signal or a phonocardiogram signal,
The analysis device according to claim 3 . The display control unit causes the display unit to display an ultrasound image whose signal intensity is adjusted by the adjustment amount when the adjustment amount is equal to or less than the threshold, and when the adjustment amount exceeds the threshold, the threshold is set. After applying, the ultrasonic image is displayed on the display unit,
The analysis device according to any one of claims 1 to 4 . The display control unit notifies that the signal strength has changed significantly when the adjustment amount exceeds a threshold.
The analysis device according to any one of claims 1 to 5 . The adjustment amount calculation unit obtains an adjustment amount of signal intensity only for image frames at regular intervals,
The display control unit uses the adjustment amount obtained in the latest image frame for image frames after the adjustment amount is obtained.
The analysis device according to any one of claims 1 to 6. a principal component analysis unit that performs principal component analysis of a received ultrasonic signal;
a signal processing unit that extracts imaging components from the received signal using the result of the principal component analysis;
an adjustment amount calculation unit that calculates an adjustment amount of the signal intensity of the signal to be visualized based on the information obtained by the principal component analysis;
a display control unit that causes a display unit to display an ultrasound image whose signal intensity has been adjusted by the adjustment amount;
with
The signal processing unit is
Calculate the integrated contribution rate up to each proper order,
Comparing the integrated contribution rate calculated for each unique order with a threshold to obtain the unique order when the threshold is exceeded for the first time, determining the unique order to be visualized,
The adjustment amount calculation unit
calculating the adjustment amount based on the natural order to be visualized;
Ultrasound diagnostic equipment. a principal component analysis unit that performs principal component analysis of a received ultrasonic signal;
a signal processor that extracts imaging components from received signals using the results of principal component analysis;
an adjustment amount calculation unit that calculates the coherency of the received signal in the time direction and calculates an adjustment amount of the signal strength of the signal to be visualized based on the coherency;
a display control unit that causes a display unit to display an ultrasound image whose signal intensity has been adjusted by the adjustment amount;
Ultrasound diagnostic device comprising.

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