JP6887767B2 - Analytical equipment, ultrasonic diagnostic equipment and analysis program - Google Patents

Description

Embodiments of the present invention relate to an analyzer, an ultrasonic diagnostic apparatus and an analysis program.

The ultrasonic diagnostic device is a diagnostic device that displays an image of in-vivo information. Ultrasound diagnostic equipment is cheaper, non-exposure and non-invasive, especially in real time, compared to other diagnostic imaging equipment such as X-ray diagnostic equipment and computed tomography (CT) equipment. It is used as a useful medical diagnostic device for observation. The range of application of ultrasonic diagnostic equipment is wide. The ultrasonic diagnostic apparatus is applied to, for example, diagnosing circulatory organs such as the heart, abdomen such as the liver and kidneys, peripheral blood vessels, obstetrics and gynecology, and breast cancer.

The ultrasonic diagnostic apparatus generally visualizes the morphology of a living tissue by expressing the magnitude of the amplitude of an ultrasonic reception signal (echo signal) with brightness. However, various research reports have reported that the received ultrasonic signal contains various other physical information. Various attempts have been made for clinical application of some of the physical information contained in the received ultrasonic signal.

For example, by calculating the amplitude statistic of the echo signal and analyzing the relationship between the average value and the variance value, for example, the content of microstructures that are difficult to visually judge can be quantified. Further, in recent years, a so-called ultrasonic elastography method that presents physical information such as hardness or elastic modulus of an organ by analyzing the amount of local movement of the organ in the subject has also been used. .. The ultrasonic elastography method is also a method of utilizing phase information or the like included in an ultrasonic signal before being imaged.

In addition, living tissues have unique damping characteristics. The ultrasonic waves applied to the subject propagate in the living body while being attenuated. At this time, if the amount of attenuation of the ultrasonic waves propagating in the living body is large, a phenomenon occurs in which a sufficient echo signal cannot be received during the scan. On the other hand, it is often the case that the characteristics of living tissue are observed by observing the state of attenuation of the echo signal. For example, a method of analyzing changes in echo brightness in the transmission / reception direction to visualize the amount of ultrasonic attenuation of a target object is known, and taking the liver as an example, it is expected to be particularly useful in the quantitative diagnosis of fatty liver. ing. Specifically, it is presumed that the subject whose echo signal is extremely reduced is fatty liver containing a large amount of lipid droplets in the liver. Similar results may occur in the case of cirrhosis.

Therefore, a plurality of methods for quantitatively diagnosing the amount of ultrasonic attenuation have been proposed. For example, a plurality of ultrasonic pulses having different center frequencies are transmitted and received, and how much the intensity of the acquired signals changes in the depth direction is compared. There is a method of estimating the amount of attenuation peculiar to the subject by this comparison. It is known that the amount of ultrasonic wave attenuation in a living body differs depending on the frequency. Therefore, by comparing the changes in the intensities of a plurality of frequency signals, a value peculiar to the target tissue can be obtained. Further, if the wide band pulse is used, the same effect as described above can be obtained by transmitting and receiving ultrasonic waves once in each direction of transmitting and receiving ultrasonic waves.

Japanese Unexamined Patent Publication No. 1-126953 Special Table No. 5-506371 Gazette

However, in each of the above-mentioned methods, the amount of attenuation is estimated by calculating the signal strength of the received signal and the change in the frequency characteristic in the depth direction, and imaging is performed. However, from imaging, it is difficult to determine the reliability of the data and what kind of distribution the luminance information is.

An object of the present embodiment is to provide an analysis device, an ultrasonic diagnostic device, and an analysis program that can assist a user's visual judgment on an image.

The analysis device according to the present embodiment includes an acquisition unit, a waveform generation unit, and a control unit. The acquisition unit acquires an echo signal based on ultrasonic scanning of the subject. The waveform generation unit generates waveform information from the echo signal in the second region excluding the first region presumed to be a structure in the region of interest of the subject. The control unit displays a waveform based on the waveform information on the display unit.

The block diagram which shows the structure of the ultrasonic diagnostic apparatus including the analysis apparatus. A flowchart showing the operation of the analyzer. The figure which shows the display example of the image displayed on the display part. The figure which shows the 1st example of the display mode of the waveform based on a uniform region. The figure which shows the 2nd example of the display mode of the waveform based on a uniform region. The figure which shows the 3rd example of the display mode of the waveform based on a uniform region. The figure which shows an example of the display mode of the waveform based on a structure area.

Hereinafter, the analysis device, the ultrasonic diagnostic device, and the analysis program related to the present embodiment will be described with reference to the drawings. In the following embodiments, the parts with the same reference numerals perform the same operation, and duplicate description will be omitted as appropriate.

In the following description, an analysis device mounted on the ultrasonic diagnostic device will be described as an example. However, it is also possible to realize it by a computer such as a medical workstation without being bound by the example. In this case, each function according to the embodiment can also be realized by installing a program for executing the process on a computer such as a workstation and expanding these on a memory. At this time, a program that allows a computer to execute the method can be stored and distributed in a storage medium such as a magnetic disk (hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory. ..

FIG. 1 is a configuration diagram showing a configuration of an ultrasonic diagnostic apparatus 1 as a medical diagnostic apparatus according to the present embodiment. As shown in the figure, the ultrasonic diagnostic apparatus 1 includes an ultrasonic probe 3, an input device 5, a monitor 7, and an apparatus main body 9. The apparatus main body 9 stores the ultrasonic transmission circuit 11, the ultrasonic reception circuit 13, the B mode processing circuit 15, the Doppler processing circuit 17, the image generation circuit 19, the image memory 21, the image synthesis circuit 23, and the storage. It has a circuit 25, an interface circuit 27, and a control circuit (central processing unit: Central Processing Unit) 29. In addition, the ultrasonic diagnostic apparatus 1 includes an electrocardiograph, an electrocardiograph, a pulse wave meter, a biological signal measuring instrument (not shown) represented by a respiratory sensor, an external storage device (not shown), and a network, and an interface circuit 27. It may be connected via.

The analysis device 2 is composed of an input device 5, a monitor 7, an image generation circuit 19, an image memory 21, an image synthesis circuit 23, a storage circuit 25, an interface circuit 27, and a control circuit 29.

The ultrasonic probe 3 has a plurality of piezoelectric vibrators, a matching layer, and a backing material provided on the back surface side of the plurality of piezoelectric vibrators. The plurality of piezoelectric vibrators are acoustic / electroreversible conversion elements such as piezoelectric ceramics. A plurality of piezoelectric vibrators are arranged in parallel and mounted on the tip of the ultrasonic probe 3. The piezoelectric vibrator generates ultrasonic waves in response to a drive signal supplied from the ultrasonic transmission circuit 11 described later. When ultrasonic waves are transmitted to the subject P via the ultrasonic probe 3, the transmitted ultrasonic waves (hereinafter referred to as transmitted ultrasonic waves) are reflected by the discontinuity surface of the acoustic impedance in the biological tissue in the subject. Will be done.

The piezoelectric vibrator receives the reflected ultrasonic waves and generates an echo signal. The amplitude of the echo signal depends on the difference in acoustic impedance with respect to the discontinuity of ultrasonic reflection. In addition, the frequency of the echo signal when the transmitted ultrasonic waves are moving and reflected on the surface of the heart wall, etc., is transmitted by the ultrasonic waves of the moving body (blood flow and the surface of the heart wall) due to the Doppler effect. It shifts depending on the velocity component of the direction.

The matching layer is provided on the ultrasonic radiation surface side of the plurality of piezoelectric vibrators in order to efficiently transmit and receive ultrasonic waves to the subject P. The backing material prevents the propagation of ultrasonic waves behind the piezoelectric vibrator.

Hereinafter, the ultrasonic probe 3 will be described as a probe that scans the area to be scanned two-dimensionally by a one-dimensional array composed of piezoelectric vibrators arranged one-dimensionally. The ultrasonic probe 3 may be a mechanical four-dimensional probe that swings a one-dimensional array in a direction orthogonal to the arrangement direction of a plurality of piezoelectric vibrators to perform three-dimensional scanning, or the piezoelectric vibrator is two-dimensional. It may be a two-dimensional array probe arranged in.

The input device 5 is connected to the device main body 9 via the interface circuit 27. The input device includes various switches, buttons, trackballs, etc. for incorporating various instructions from the operator, various conditions, setting instructions of the region of interest (ROI), various image quality conditions, setting instructions, etc. into the device main body 9. It has a mouse, keyboard, etc. The input device 5 may have a touch pad for performing an input operation by touching the operation surface, a touch panel display in which the display screen and the touch pad are integrated, a microphone, and the like.

The input device 5 has a function of comprehensively executing the setting function 291 and the estimation function 292 described later (hereinafter, also referred to as a structure estimation function), a gain inverse correction function 293 described later, a sound field characteristic correction function 294, and an analysis function. An start instruction (hereinafter, referred to as an attenuation quantification start instruction) for executing a function for comprehensively executing 295 (hereinafter, also referred to as a tissue property analysis function) is input. At this time, the signal related to the input of the attenuation quantification start instruction is output to the control circuit 29 described later. The input device 5 also inputs a start instruction for executing a function (hereinafter, also referred to as a waveform display function) that comprehensively executes the acquisition function 296, the waveform information generation function 297, and the display control function 298, which will be described later. ..

The input device 5 is not limited to a device including physical operation parts such as a mouse and a keyboard. For example, an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the ultrasonic diagnostic apparatus 1 and outputs the received electric signal to various circuits is also input. It is included in the example of the device 5.

The monitor 7 displays morphological information in the living body, blood flow information, and the like as an image based on the video signals output from the image generation circuit 19, the image synthesis circuit, and the like 23, which will be described later. Further, the monitor 7 displays the analysis result by the waveform information generation function 297. As the monitor, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used. The monitor 7 corresponds to a display unit and a display circuit.

The ultrasonic transmission circuit 11 includes a pulse generator 111, a transmission delay circuit 113, and a pulser circuit 115. The ultrasonic transmission circuit 11 is an example of an ultrasonic transmission unit, and may have a processor. The pulse generator 111 repeatedly generates rate pulses for forming transmitted ultrasonic waves at a predetermined rate frequency fr Hz (period: 1 / fr seconds). The generated rate pulse is distributed to the number of channels and sent to the transmission delay circuit 113.

The transmission delay circuit 113 sets the delay time (hereinafter referred to as transmission delay time) required for converging the transmitted ultrasonic waves in a beam shape and determining the transmission directivity for each rate pulse for each of the plurality of channels. give away. The transmission delay time (hereinafter, referred to as a transmission delay pattern) relating to the transmission direction or the transmission direction of the transmission ultrasonic wave is stored in the storage circuit 25. The transmission delay pattern stored in the storage circuit 25 is referred to by the control circuit 29 when transmitting ultrasonic waves.

The pulsar circuit 115 applies a voltage pulse (drive signal) to each oscillator of the ultrasonic probe 3 at a timing based on this rate pulse. As a result, the ultrasonic beam is transmitted to the subject P.

The ultrasonic transmission circuit 11 transmits ultrasonic waves (hereinafter referred to as attenuation quantification ultrasonic waves) to the subject P based on the attenuation quantification condition, triggered by the generation of B mode data corresponding to one frame, which will be described later. .. The attenuation quantification condition is a transmission condition for generating the attenuation quantification ultrasonic wave and a reception condition for receiving the attenuation quantification ultrasonic wave. The transmission conditions are, for example, the transmission center frequency of the attenuation quantification ultrasonic wave and the transmission bandwidth of the attenuation quantification ultrasonic wave. The reception conditions are, for example, the reception center frequency and the reception bandwidth of the attenuation quantification ultrasonic wave. The attenuation quantification condition is stored in the storage circuit 25.

The transmission condition is not limited to the above two types, and may be, for example, a condition in which a plurality of ultrasonic waves for quantifying attenuation having different frequencies are transmitted to one scanning line. Further, the transmission condition may be, for example, a condition in which two ultrasonic waves for quantifying attenuation whose phases are inverted are transmitted to one scanning line. The transmission center frequency under the transmission condition is, for example, a transmission center frequency higher than the transmission center frequency of the B-mode ultrasonic wave. Further, the bandwidth under the transmission condition is a bandwidth narrower than the bandwidth of the ultrasonic wave for B mode (hereinafter, referred to as a narrow band). The transmission / reception conditions are not necessarily limited to two types, and one type may be used. Further, different types may be used depending on the transmission / reception conditions. For example, under the transmission condition, one type of narrow-band ultrasonic wave may be transmitted, and under the reception condition, a wide band may be set for the B mode, and an extremely narrow bandwidth may be set for the attenuation determination.

The attenuation quantification condition is read from the storage circuit 25 to the control circuit 29 by the operator's instruction to start the attenuation quantification via the input device 5. The ultrasonic transmission circuit 11 is controlled by the control circuit 29 according to the transmission conditions in the attenuation quantification condition. For example, in the ultrasonic scan, the ultrasonic transmission circuit 11 transmits a plurality of ultrasonic waves having different frequencies to the subject P via the ultrasonic probe 3 according to the transmission conditions. In the ultrasonic scan, the ultrasonic transmission circuit 11 transmits ultrasonic waves in a band narrower than the frequency band in the ultrasonic transmission related to the B mode to the subject P via the ultrasonic probe 3 according to the transmission conditions.

The ultrasonic receiving circuit 13 includes a preamplifier 131, an analog-to-digital (hereinafter referred to as A / D) converter (not shown), a reception delay circuit 133, and an adder 135. The ultrasonic wave receiving circuit is an example of an ultrasonic wave receiving unit, and may have a processor. The preamplifier 131 amplifies the echo signal from the subject P captured via the ultrasonic probe 3 for each channel. The A / D converter converts the amplified received echo signal into a digital signal. For the analog signal before A / D conversion, an analog gain is given as STC (sentive time control) or TGC (time gain control).

The reception delay circuit 133 gives the reception echo signal converted into a digital signal a delay time (hereinafter, referred to as a reception delay time) necessary for determining the reception directivity. The reception delay circuit 133 is, for example, a digital beam former. A digital gain is given as STC or TGC to the digital signal output from the reception delay circuit 133. The reception delay time (hereinafter, referred to as a reception delay pattern) relating to the reception direction or the reception direction of the echo signal is stored in the storage circuit 25 described later. The reception delay pattern stored in the storage circuit 25 is referred to by the control circuit 29 as in the case of transmission.

The signal due to the reflected wave becomes weaker in the deeper part of the subject due to the attenuation of the ultrasonic wave in the subject. Therefore, the analog gain and the digital gain are gains that amplify the amplitude of the signal due to the ultrasonic waves reflected in the deep part of the subject in order to compensate for this attenuation.

The adder 135 adds a plurality of echo signals with a delay time. By this addition, the ultrasonic reception circuit 13 generates a reception signal in which the reflection component from the direction corresponding to the reception directivity is emphasized. The overall directivity of ultrasonic transmission / reception is determined by the transmission directivity and the reception directivity. This overall directivity determines the ultrasonic beam (so-called "ultrasonic scanning line").

The ultrasonic wave receiving circuit 13 receives the ultrasonic wave for attenuation quantification according to the reception condition in the attenuation quantification condition. The reception center frequency under the reception condition is substantially the same as the transmission center frequency of the attenuation quantification ultrasonic wave, and is constant without changing with respect to the depth direction of the scanned region. Further, the reception bandwidth under the reception condition is substantially the same bandwidth as the narrow bandwidth. The ultrasonic wave receiving circuit 13 is controlled by the control circuit 29 according to the receiving condition in the attenuation quantitative condition.

Specifically, the ultrasonic wave receiving circuit 13 receives the reflected wave of the ultrasonic wave for attenuation quantification transmitted to the subject P in accordance with the receiving conditions, triggered by the generation of the B mode data described later corresponding to one frame. .. The ultrasonic wave receiving circuit 13 generates the received data for attenuation quantification by receiving the reflected wave of the ultrasonic wave for attenuation quantification. The ultrasonic wave receiving circuit 13 outputs the received data for quantifying attenuation to the B mode processing circuit 15. The ultrasonic wave receiving circuit 13 may output the received data for quantifying attenuation to the control circuit 29 and the storage circuit 25.

The B-mode processing circuit 15 includes an envelope detector, a logarithmic converter, and the like (not shown). The B-mode processing circuit 15 is an example of a B-mode processing unit and has a processor. The envelope detector executes the envelope detector on the received signal output from the ultrasonic reception circuit 13. The envelope detector outputs the envelope-detected signal to a logarithmic converter described later. The logarithmic converter performs logarithmic conversion on the envelope-detected signal to relatively emphasize the weak signal. The B-mode processing circuit 15 generates a signal value (B-mode data) for each depth in each scanning line and each ultrasonic transmission / reception based on the signal emphasized by the logarithmic converter.

The B-mode data corresponds to data in which the intensity of the signal output from the logarithmic converter is expressed as the brightness of the luminance. The output from the B-mode processing circuit 15 is output to the image generation circuit 19. The output from the B-mode processing circuit 15 is displayed on the monitor 7 as a B-mode image in which the intensity of the reflected wave is represented by the brightness. The B-mode processing circuit 15 generates B-mode data for attenuation quantification by the above processing procedure based on the received data for attenuation quantification. The B-mode processing circuit 15 outputs the attenuation quantification B-mode data to the control circuit 29 and the storage circuit 25.

When the ultrasonic probe 3 is a mechanical four-dimensional probe or a two-dimensional array probe, the B-mode processing circuit 15 has an azimuth (azimuth) direction, an elevation (elevation) direction, and a depth direction in the area to be scanned. Three-dimensional B-mode data composed of a plurality of signal values arranged in association with each other (range direction) may be generated. The range direction is the depth direction on the scanning line. The azimuth direction is, for example, the electron scanning direction along the arrangement direction of the piezoelectric vibrators in the one-dimensional array. The elevation direction is, for example, the mechanical swing direction of the one-dimensional array.

The three-dimensional B mode data may be data in which a plurality of pixel values, a plurality of brightness values, and the like are arranged in association with each other in the azimuth direction, the elevation direction, and the range direction along the scanning line. .. Further, the three-dimensional B mode data may be data related to the ROI set in advance in the area to be scanned. Further, the B mode processing circuit 15 may generate volume data instead of the three-dimensional B mode data. Hereinafter, the data generated by the B mode processing circuit 15 will be collectively referred to as B mode data.

The Doppler processing circuit 17 receives an echo signal from the ultrasonic wave receiving circuit 13, and frequency-analyzes velocity information with respect to the received echo signal. The Doppler processing circuit 17 is an example of a Doppler processing unit and has a processor. The Doppler processing circuit 17 extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect from the echo signal received from the ultrasonic receiving circuit 13. The Doppler processing circuit 17 obtains blood flow information such as average velocity, dispersion, and power for multiple points on the scanning line. The Doppler processing circuit 17 outputs the obtained blood flow information to the image generation circuit 19. The output from the Doppler processing circuit 17 is displayed in color on the monitor 7 as a Doppler waveform image, an average velocity image, a distributed image, a power image, and a combination image thereof.

For example, the Doppler processing circuit 17 includes a mixer (not shown), a low-pass filter (hereinafter referred to as LPF), a speed / dispersion / Power calculation circuit, and the like. The mixer multiplies the received signal output from the ultrasonic wave receiving circuit 13 by a reference signal having the same frequency f0 as the transmitting frequency. By this multiplication, a signal having a component of the Doppler shift frequency fd and a signal having a frequency component of (2f0 + fd) can be obtained. The LPF removes a signal having a high frequency component (2f0 + fd) from the signal having two kinds of frequency components from the mixer. The Doppler processing circuit 17 generates a Doppler signal having a Doppler shift frequency fd component by removing a signal having a high frequency component (2f0 + fd).

The Doppler processing circuit 17 may use an orthogonal detection method to generate a Doppler signal. At this time, the received signal (RF signal) is orthogonally detected and converted into an IQ signal. The Doppler processing unit 142 generates a Doppler signal having a component of the Doppler shift frequency fd by performing a complex Fourier transform on the IQ signal. The Doppler signal is, for example, a blood flow, tissue, or Doppler component of a contrast agent.

The speed / dispersion / power calculation circuit includes an MTI (Moving Target Indicator) filter, an LPF filter, an autocorrelation calculation device, and the like (not shown). It should be noted that a cross-correlation calculator may be provided instead of the autocorrelation calculator. The MTI filter removes the Doppler component (clutter component) caused by the respiratory movement and pulsatile movement of the organ with respect to the generated Doppler signal. The MTI filter is used to extract a Doppler component related to blood flow (hereinafter referred to as a blood flow Doppler component) from a Doppler signal. The LPF is used to extract a Doppler component (hereinafter, referred to as a tissue Doppler component) related to tissue movement from a Doppler signal.

The autocorrelation calculator calculates the autocorrelation value for the blood flow Doppler component and the tissue Doppler component. The autocorrelation calculator calculates the average velocity value of blood flow and tissue, the dispersion value, the reflection intensity (power) of the Doppler signal, and the like based on the calculated autocorrelation value. The velocity / dispersion / Power arithmetic circuit generates color Doppler data at each position in a predetermined region based on the average velocity value of blood flow and tissue based on a plurality of Doppler signals, the dispersion value, the reflection intensity of the Doppler signal, and the like. Hereinafter, the Doppler signal and the color Doppler data are collectively referred to as Doppler data.

The image generation circuit 19 has a digital scan converter (Digital Scan Converter: hereinafter referred to as DSC) and the like (hereinafter referred to as DSC) (not shown). The image generation circuit 19 is an example of an image generation unit and has a processor. The image generation circuit 19 executes coordinate conversion processing (resampling) on the DSC. The coordinate conversion process is, for example, a process of converting a scanning line signal string of an ultrasonic scan composed of B mode data and Doppler data into a scanning line signal string of a general video format represented by a television or the like. ..

The image generation circuit 19 generates an ultrasonic image as a display image by a coordinate conversion process. Specifically, the image generation circuit 19 generates a B-mode image based on the B-mode data. The image generation circuit 19 generates an attenuation B-mode image based on the attenuation quantification B-mode data. The B-mode image and the attenuated B-mode image have pixel values (brightness values) that reflect the characteristics of an ultrasonic probe such as focusing of sound waves and the sound field characteristics of an ultrasonic beam (for example, a transmission / reception beam). For example, in a B-mode image, the brightness is relatively higher in the area to be scanned near the focus of ultrasonic waves than in the non-focused portion.

The image generation circuit 19 generates Doppler images such as an average velocity image, a distributed image, and a power image based on the Doppler data. Further, the image generation circuit 19 generates an attenuated image showing the degree of ultrasonic wave attenuation at each position of the ROI in the scanned region based on the analysis result analyzed by the analysis function 295.

The image memory 21 stores data (hereinafter, referred to as image data) corresponding to the generated ultrasonic image (B mode image, average velocity image, distributed image, power image, attenuated image). The image data stored in the image memory 21 is read out according to the instruction of the operator via the input device 5. The image memory 21 is, for example, a memory for storing ultrasonic images corresponding to a plurality of frames immediately before freezing. By continuously displaying (cine-displaying) the images stored in the cine memory at a predetermined frame rate, the ultrasonic moving image is displayed as a moving image on the monitor 7.

The image memory 21 is realized by, for example, an integrated circuit storage device (RAM (Random Access Memory), ROM (Read-Only Memory), etc.). The realization of the image memory 21 is not limited to the integrated circuit storage device, and may be any storage device.

The image synthesis circuit 23 synthesizes character information, scales, and the like of various parameters with the ultrasonic image. The image synthesis circuit 23 is an example of an image synthesis unit and has a processor. The image synthesis circuit 23 outputs the synthesized ultrasonic image to the monitor 7, which will be described later. The image composition circuit 23 generates an attenuated superimposed image in which the attenuated image is aligned and superimposed on the B mode image. The image synthesis circuit 23 outputs the generated attenuation superimposed image to the monitor 7.

The storage circuit 25 is a storage device such as an HDD (hard disk drive), an SSD (solid state drive), or an integrated circuit storage device (RAM, ROM, etc.) that stores various information. The storage circuit 25 corresponds to a storage unit. Further, the storage circuit 25 may be realized by a drive device that reads and writes various information between a CD-ROM drive, a DVD drive, and the like. Further, the storage circuit 25 is a drive for reading and writing various information between a magnetic disk (floppy (registered trademark) disk, etc.), an optical disk (CD-ROM, DVD, MO, etc.), a portable storage medium such as a semiconductor memory, and the like. It may be realized by the device.

The storage circuit 25 stores a plurality of reception delay patterns having different focus depths and a plurality of transmission delay patterns. The storage circuit 25 stores the control program of the ultrasonic diagnostic apparatus 1, the diagnostic protocol, and the medical analysis program described later. The storage circuit 25 stores various data groups such as ultrasonic transmission / reception conditions and diagnostic information (patient ID, doctor's findings, etc.). The storage circuit 25 shows the received signal generated by the ultrasonic wave receiving circuit 13, the B mode data generated by the B mode processing circuit 15, the Doppler data generated by the Doppler processing circuit 17, and the analysis result by the tissue property analysis function. The analysis data and the waveform information by the waveform information generation function 297 are stored.

Further, the storage circuit 25 is a program related to the execution of the structure estimation function, the size and set position of a plurality of regions set in the scanned region (attenuation B mode image) related to the collection of the attenuation quantification B mode data (hereinafter, (Called a structure estimation program), etc. are stored. The storage circuit 25 stores a threshold value (hereinafter, referred to as a structure determination threshold value) referred to in the structure estimation function. The storage circuit 25 is a program related to execution of the reverse correction data used in the gain reverse correction function 293, the sound field characteristic correction data used in the sound field characteristic correction function 294, and the texture property analysis function (hereinafter, referred to as a waveform property analysis program). , The waveform information generated by the waveform information generation function 297, the waveform presentation program related to the execution of the acquisition function 296, the waveform information generation function 297, and the display control function 298 are stored. Hereinafter, the structure estimation program, the tissue property analysis program, and the waveform display program are collectively referred to as a medical analysis program.

The storage circuit 25 may store a correspondence table (hereinafter, referred to as a reverse correction correspondence table) instead of the reverse correction data. Further, the storage circuit 25 may store a correspondence table (hereinafter, referred to as a sound field characteristic correction correspondence table) instead of the sound field characteristic correction data.

The reverse correction data is data for canceling (cancelling) the analog gain and the digital gain given by the STC or TGC with respect to the data (received signal, received data) obtained by the ultrasonic scan. Specifically, the reverse correction data is data indicating the response of the gain (gain) given to the data obtained by the ultrasonic scan in the depth direction. That is, by applying the reverse correction data to the B mode data, the gain-corrected B-mode data is converted into the B-mode data before the gain correction.

The reverse correction correspondence table is a correspondence table for canceling the gain correction by STC or TGC. Specifically, the inverse correction correspondence table is a correspondence table showing the response of the gain (gain) given to the data obtained by the ultrasonic scan in the depth direction, and the B mode data after the gain correction is used. It is a correspondence table for conversion to B mode data before gain correction.

The sound field characteristic correction data is data for canceling the dependence of the sound field characteristic in the B mode data before the gain correction. That is, by applying the sound field characteristic correction data to the B mode data, the B mode data that depends on the sound field characteristic is converted into the B mode data that does not depend on the sound field characteristic. The sound field characteristic correction correspondence table is a correspondence table for canceling the dependence of the sound field characteristic in the B mode data. Specifically, the sound field characteristic correction correspondence table is a correspondence table for converting B mode data that depends on the sound field characteristic into B mode data that does not depend on the sound field characteristic.

The sound field characteristic correction data and the sound field characteristic correction correspondence table are obtained, for example, in the depth direction obtained when an ultrasonic scan is performed on an object in which ultrasonic waves are unattenuated and have a uniform scatterer. Corresponds to the distribution of pixel values (or brightness values). The sound field characteristic correction data and the sound field characteristic correction correspondence table are generated in advance based on the actual measurement data acquired by performing an ultrasonic scan on a phantom in which ultrasonic waves are unattenuated and uniform. ..

In addition, the sound field characteristic correction data and the sound field characteristic correction correspondence table are obtained by differentiating the attenuation of ultrasonic waves by this phantom from the actual measurement data measured by ultrasonic scanning for a phantom having a certain attenuation with respect to ultrasonic waves. May be generated by. Further, the sound field characteristic correction data and the sound field characteristic correction correspondence table may be generated by other means such as simulation.

The storage circuit 25 stores various medical images such as a B-mode image, an average velocity image, a distributed image, a power image, an attenuation image, and an attenuation superimposition image. The storage circuit 25 stores a plurality of hues corresponding to a plurality of attenuation coefficients, which will be described later. The storage circuit 25 stores a predetermined opacity or transparency with respect to the attenuated image. The image memory 21 described above may be provided in the storage circuit 25. Further, when the CFAR (Contrast False Alarm Rate) process, which will be described later, is executed as the structure estimation function, the storage circuit 25 may store a program related to the CFAR process.

The interface circuit 27 is an interface relating to an input device 5, an operation panel (not shown), a network, an external storage device (not shown), and a biological signal measuring instrument. Data such as ultrasonic images and analysis results obtained by the device main body 9 can be transferred to another device via the interface circuit 27 and the network. The interface circuit 27 can also download a medical image of a subject acquired by another medical image diagnostic apparatus (not shown) via a network. The interface circuit 27 corresponds to the interface unit and may have a processor.

The control circuit 29 has a function as an information processing device (computer), and is a control means (processor) that controls the operation of the ultrasonic diagnostic device 1. The control circuit 29 reads a control program for executing image generation / display and the like from the storage circuit 25 and executes calculations / controls related to various processes.

The control circuit 29 reads out the attenuation quantification condition from the storage circuit 25 in response to the attenuation quantification start instruction. The control circuit 29 controls the ultrasonic transmission circuit 11 and the ultrasonic reception circuit 13 according to the read attenuation quantitative conditions. Specifically, the control circuit 29 controls the ultrasonic transmission circuit 11 according to the read transmission conditions. As a result, the ultrasonic transmission circuit 11 transmits the ultrasonic wave for quantifying attenuation to the subject P after generating the B mode data corresponding to one frame. Further, the control circuit 29 controls the ultrasonic wave receiving circuit 13 according to the read reception conditions. As a result, the ultrasonic wave receiving circuit 13 receives the reflected wave of the attenuation quantification ultrasonic wave transmitted to the subject P according to the receiving conditions.

In this embodiment, each process performed by the setting function 291 and the estimation function 292, the gain reverse correction function 293, the sound field characteristic correction function 294, the analysis function 295, the acquisition function 296, the waveform information generation function 297, and the display control function 298. The functions are stored in the storage circuit 25 in the form of a program that can be executed by a computer. The control circuit 29 is a processor that realizes the functions corresponding to each program by reading the programs corresponding to these functions from the storage circuit 25 and executing the programs.

The term "processor" used in the above description refers to, for example, a CPU, a GPU (Graphical Processing Unit), an integrated circuit for a specific application (Application Specific Integrated Circuit: ASIC), a programmable logic device (for example, a simple programmable logic device (Simple)). It means a circuit such as a Programgable Logical Device (SPLD), a compound programmable logic device (Complex Programmable Logic Device: CPLD), and a field programmable gate array (Field Programmable Gate Array: FPGA).

The processor realizes the function by reading and executing the program stored in the storage circuit 25. Instead of storing the program in the storage circuit 25, the program may be directly incorporated in the circuit of the processor. In this case, the processor realizes the function by reading and executing the program embedded in the circuit. Similarly, other circuits such as the ultrasonic transmission circuit 11, the ultrasonic reception circuit 13, the B mode processing circuit 15, the Doppler processing circuit 17, the image generation circuit 19, the image synthesis circuit 23, and the interface circuit 27 are also the above-mentioned processors. It is composed of electronic circuits such as.

The control circuit 29 reads the medical analysis program from the storage circuit 25 in response to the attenuation quantification start instruction. The control circuit 29 realizes the structure estimation function and the tissue property analysis function by executing the read medical analysis program. Specifically, the control circuit 29 reads out the structure estimation program and the tissue property analysis program from the storage circuit 25. The control circuit 29 executes the read-out structure estimation program, and based on the B-mode data for attenuation quantification obtained by ultrasonic scanning using ultrasonic waves for attenuation quantification, the position of the structure in the subject. To estimate.

The control circuit 29 analyzes the tissue properties in the scanned region corresponding to the B-mode data for attenuation quantification by executing the read-out tissue property analysis program, for example, with the estimation of the position of the structure as an opportunity.
The control circuit 29 acquires an echo signal based on ultrasonic scanning of the subject P. The control circuit 29 obtains waveform information from the echo signal corresponding to the uniform region (also referred to as the second region) excluding the structure region (also referred to as the first region) presumed to be the structure in the ROI of the subject P. Generate. The control circuit 29 displays a waveform based on the waveform information on a display unit such as a monitor 7. The control circuit 29 may display the waveform and at least one of the medical images (B-mode image and attenuated image) together.

(Tissue property analysis function)
The tissue property analysis function is a function executed by the control circuit 29 according to the tissue property analysis program. Specifically, the tissue property analysis function analyzes the tissue property at a position other than the position of the structure estimated in the attenuation B mode image based on the B mode data for quantification of attenuation. The tissue property analysis function includes a gain inverse correction function 293, a sound field characteristic correction function 294, an analysis function 295, and a display control function 298. Hereinafter, each function in the tissue property analysis function will be described in detail.

Prior to the execution of the gain inverse correction function 293, the control circuit 29 corresponds to a plurality of positions in the attenuation quantification B-mode data excluding the position of the structure estimated in the scanned area corresponding to the attenuation B-mode image. Estimate the data (hereinafter referred to as partial data for attenuation quantification).

The control circuit 29 that realizes the gain reverse correction function 293 reads the reverse correction data from the storage circuit 25. The control circuit 29 subtracts the inverse correction data from the attenuation quantification partial data corresponding to a plurality of positions excluding the position of the structure estimated in the scanned region. As a result, the control circuit 29 generates partial data for quantifying attenuation before gain correction. The control circuit 29 may read the inverse correction correspondence table from the storage circuit 25. At this time, the control circuit 29 converts the attenuation quantification partial data into the attenuation quantification partial data before the gain correction according to the inverse correction correspondence table. That is, the gain reverse correction function 293 cancels the gain correction for the partial data for quantifying attenuation.

Due to the gain inverse correction function 293, the control circuit 29 causes the control circuit 29 to receive data at the time when the ultrasonic probe 3 receives the reflected wave of the ultrasonic wave for quantifying attenuation, that is, the pure ultrasonic signal in the depth direction along the depth direction. Restore strength. If it is possible to output uncorrected gain-corrected partial data (raw data) for attenuation determination from the ultrasonic wave receiving circuit 13, the gain reverse correction function 293 becomes unnecessary.

The control circuit 29 that realizes the sound field characteristic correction function 294 reads out the sound field characteristic correction data from the storage circuit 25. The control circuit 29 subtracts the sound field characteristic correction data from the partial data for quantifying the attenuation before the gain correction. As a result, the control circuit 29 generates partial data for attenuation quantification (hereinafter, referred to as attenuation data) before gain correction without depending on the sound field characteristics. The control circuit 29 may read the sound field characteristic correction correspondence table from the storage circuit 25. At this time, the control circuit 29 converts the attenuation quantification partial data before the gain correction into the attenuation data according to the sound field characteristic correction correspondence table. That is, the control circuit 29 cancels the dependence of the sound field characteristic in the partial data for attenuation determination before gain correction based on the sound field characteristic in the ultrasonic scan.

With the sound field characteristic correction function 294, the control circuit 29 determines the amount of change in the pixel value (or luminance value) peculiar to the shape of the ultrasonic beam and the shape of the ultrasonic probe 3 in the B mode for attenuation determination before gain correction. Exclude from data. Due to this exclusion, the control circuit 29 generates attenuation data having pixel values (or luminance values) that reflect the degree to which the ultrasonic waves are purely attenuated by the tissue in the subject. The attenuation data corresponds to the correction data corrected by the gain inverse correction function 293 and the sound field characteristic correction function 294.

The control circuit 29 that realizes the waveform information generation function 297 is a plurality of positions in the subject (hereinafter, hereinafter, excluding the estimated position of the structure) based on the attenuation data obtained by ultrasonic scanning of the subject P. The tissue properties in the non-structural region or uniform region) are analyzed. That is, the control circuit 29 that realizes the waveform information generation function 297 calculates the amount of attenuation of the ultrasonic wave for quantifying attenuation propagating in the subject.

Specifically, the control circuit 29 calculates a differential value along the depth direction in the pixel value (or luminance value) in the non-structural region in the attenuation data. The differential value is, for example, a value obtained by dividing the difference value of the pixel values of two adjacent pixels along the depth direction by the distance (distance) between the two pixels in each of a plurality of pixels in the non-structural region. Corresponds to.

Next, the control circuit 29 multiplies the calculated differential value by 1/2, taking into account the round-trip portion of the ultrasonic wave. As a result, the control circuit 29 calculates the amount of ultrasonic wave attenuation (dB / cm) with respect to the transmission center frequency of the ultrasonic wave for quantifying attenuation for a plurality of pixels (positions) included in the non-structural region. Further, the control circuit 29 divides the calculated attenuation amount by the transmission center frequency of the ultrasonic wave for quantifying attenuation. By this division, the control circuit 29 calculates the attenuation coefficient (dB / cm / Hz) in a plurality of pixels (positions) included in the non-structural region.

The attenuation coefficient does not depend on the transmission center frequency of the ultrasonic wave for quantifying attenuation. The attenuation coefficient is a numerical value representing the properties of the tissue to be diagnosed. By the above-mentioned various calculations, the control circuit 29 generates analysis data (hereinafter, referred to as attenuation coefficient data) showing the attenuation coefficient at a plurality of positions included in the non-structural region. The control circuit 29 outputs the attenuation coefficient data to the image generation circuit 19, the storage circuit 25, and the like.

The texture property is not limited to the attenuation coefficient obtained by analyzing the luminance value or the pixel value, and may be an amount that reflects the amount of attenuation obtained by other analysis. For example, when estimating a structure such as a blood vessel in the liver, it is desirable to use Doppler data. When a plurality of ultrasonic waves for quantifying attenuation having different frequencies are transmitted and received for one scanning line, the control circuit 29 that realizes the waveform information generation function 297 converts the Doppler data at a plurality of positions included in the non-structural region into Doppler data. By performing frequency analysis based on this, parameters indicating the texture properties at a plurality of positions included in the non-structural region may be calculated. Specifically, the control circuit 29 calculates the difference in the amount of attenuation due to the difference in frequency as a tissue property using Doppler data corresponding to each of the plurality of ultrasonic waves for quantifying attenuation.

Further, when an ultrasonic wave having a band narrower than the frequency band in the ultrasonic wave transmission related to the B mode is transmitted to the subject P as an ultrasonic wave for quantifying attenuation, the control circuit 29 acquires the ultrasonic wave for quantifying attenuation in a narrow band. Perform frequency analysis on the generated data. Next, the control circuit 29 calculates the amount of attenuation as a texture based on the frequency characteristics in the frequency analysis.

The control circuit 29 that realizes the display control function 298 displays the attenuated image of the analysis result on the monitor 7. Specifically, the control circuit 29 outputs the attenuation coefficient data to the image generation circuit 19. The image generation circuit 19 generates an attenuation image based on the attenuation coefficient data. At this time, the control circuit 29 controls the image generation circuit 19 in order to impart a hue corresponding to the attenuation coefficient to each of the plurality of pixels. Due to this control, the attenuated image has a hue corresponding to the attenuation coefficient.

In the region corresponding to the position of the structure, the attenuated image is in a missing state. The image generation circuit 19 outputs the attenuated image to the image composition circuit 23.

Under the control of the control circuit 29, the image synthesis circuit 23 aligns the attenuated image with the B-mode image relating to the area to be scanned, which is substantially the same as the area to be scanned for collecting the B-mode data for quantifying attenuation. To execute. The image composition circuit 23 converts the attenuated image into a predetermined opacity or transparency under the control of the control circuit 29.

The image composition circuit 23 generates an attenuation superimposed image in which an attenuation image having a predetermined opacity or transparency is superimposed on the B mode image. The image synthesis circuit 23 synthesizes a legend or the like according to the hue of the attenuation coefficient with the attenuation superposed image. The image synthesis circuit 23 outputs an attenuated superimposed image obtained by synthesizing a legend or the like to the monitor 7.

The monitor 7 displays the amount of attenuation as an analysis result at each of the plurality of positions in the subject excluding the position of the structure. Specifically, the monitor 7 displays an attenuated superimposed image in which a legend or the like is combined.

As described above, in the present embodiment, the case of analyzing the attenuation amount of the ultrasonic wave propagating in the subject as the tissue property is taken as an example. However, the tissue property is not limited to the amount of attenuation, and may be an amount indicating the property of the tissue to be diagnosed, such as elastic modulus (Young's modulus), viscosity rate, and strain. At this time, the tissue property is acquired by, for example, an ultrasonic elastography method. The analysis function 295 has various analysis functions related to static or dynamic elastography methods. At this time, the control circuit 29 that realizes the analysis function 295 calculates an index value (viscosity parameter, elasticity parameter) relating to at least one of the viscosity and elasticity of the tissue in the subject as the tissue property. Further, the image generated by the ultrasonic elastography method (elastic image, viscous image, distorted image, etc.) corresponds to the attenuated image.

(Structure estimation function)
The structure estimation function is, for example, the position of a structure by evaluating non-uniformity at a plurality of positions in the subject based on B-mode data for attenuation determination obtained by ultrasonic scanning of the subject P. Includes the ability to estimate. There are various methods for estimating a structure as a structure estimation function. Hereinafter, as an example, a plurality of pixel values corresponding to a plurality of pixels included in each of a plurality of regions set in an attenuation B mode image. A method using the average value (or the brightness value) and the dispersion value will be described.

This method generally utilizes the fact that the frequency distribution (histogram) of the B-mode data for attenuation quantification shows a Rayleigh distribution in a region having a uniform scatterer, such as the parenchyma of a healthy liver. In a region with a uniform scatterer, when the frequency distribution of the B-mode data for attenuation quantification follows the Rayleigh distribution, the average value (μ) and variance value (σ) of the multiple pixel values in this region are as follows. Relationship.

μ ² = (π / (4-π)) × σ ² ... (1)
When the structure is included in the region related to the calculation of the mean value and the variance value, the variance value of the frequency distribution of the B-mode data for attenuation quantification is calculated by the Rayleigh distribution because the scatterer is non-uniform. Greater than the variance value. In addition, the more significantly different the properties of the structure from the surroundings (eg, when the area of the structure corresponds to a calcified area), the greater the dispersion value. Therefore, by calculating the variance value in each of the plurality of regions set in the region to be scanned, it is possible to determine the presence or absence of a structure in each of the pixels representing the region.

However, the larger the pixel value, the larger the variance value. Therefore, simply calculating the variance value itself determines the presence or absence of a structure, that is, the presence or absence of deviation from the Rayleigh distribution obtained in the case of a uniform scatterer. It cannot be determined. Therefore, in the present embodiment, a Rayleigh distribution having the same average value as the average value of the pixel values in the set region is assumed for the set region. Under this assumption, in the set region with respect to the variance value {(4 / π-1) × μ ² } calculated using the average value of the pixel values in the set region and the equation (1). The ratio of the variance value σ ² of the pixel values (hereinafter referred to as the normalized local variance Rσ) is calculated. Specifically, the normalized local variance Rσ has the following equation.

Rσ = (π / (4-π)) × σ ² / μ ² ... (2)
Molecules (sigma ²⁾ on the right-hand side of Equation (2) is the variance value of the measured, calculated from a plurality of pixel values corresponding to a plurality of pixels that are included in the set region. The denominator {(π / (4-π)) × μ ² } on the right side of equation (2) is the average value μ calculated from the pixel values of the variance corresponding to each of the plurality of pixels included in the set region. It is a dispersion value when it is assumed that a plurality of pixel values in a set region form a Rayleigh distribution using the above equation (1).

When the normalized local variance Rσ is close to 1, the distribution of pixel values in the set region can be regarded as the Rayleigh distribution. Further, when the normalized local variance Rσ is a value larger than 1, the distribution of a plurality of pixel values included in the set region deviates from the Rayleigh distribution, and uniform scattering occurs in the set region. It is presumed that it contains structures that deviate from the body. That is, the normalized local variance Rσ corresponds to an index for determining the presence or absence of a structure in the set region.

The control circuit 29 that realizes the setting function 291 is a plurality of determination areas in the area to be scanned (attenuation B mode image) in which the attenuation quantification B mode data is collected, that is, the scanning area in the ultrasonic scan by the attenuation quantification ultrasonic wave. To set. The set plurality of determination regions have a predetermined size with each of the plurality of pixels in the attenuated B mode image as the center (hereinafter referred to as the center pixel) or the center of gravity. The size of the determination area set in the attenuation B mode image may be appropriately changed according to the instruction of the operator via the input device 5. The control circuit 29 may set a plurality of determination regions in the attenuation B mode image by sweeping one region for each width of a predetermined pixel.

The control circuit 29 that realizes the estimation function 292 estimates the position of the structure based on the pixel value (or the brightness value) corresponding to each of the plurality of pixels included in each of the set plurality of determination regions. At this time, the pixel value corresponds to the pixel value in the attenuation quantification B mode data. As the pixel value used by the estimation function 292, the pixel value in the normal B mode data may be used. Specifically, the control circuit 29 calculates an average value of pixel values (or luminance values) and a dispersion value in each of the plurality of determination regions. The control circuit 29 calculates the normalized local variance Rσ based on the mean value and the variance value. The calculated normalized local variance Rσ may be stored in the storage circuit 25. Further, the normalized local variance Rσ has a hue corresponding to the value of the normalized local variance Rσ, is superimposed on the B-mode image in the same scanned area as the scanned area regarding the normalized local variance Rσ, and is displayed on the monitor 7. You may.

The control circuit 29 associates the calculated normalized local variance Rσ with a position representing the determination region set by the setting function 291, for example, the position of the central pixel. The control circuit 29 reads the structure determination threshold value from the storage circuit 25. The structure determination threshold value is a numerical value of 1 or more. The structure determination threshold value may be appropriately changed according to the instruction of the operator via the input device 5. The control circuit 29 compares the read structure determination threshold value with the normalized local variance Rσ. The control circuit 29 estimates the position associated with the normalized local variance Rσ larger than the structure determination threshold value as the position of the structure.

The control circuit 29 that realizes the estimation function 292 may output the position of the structure estimated in the scanned region corresponding to the attenuated B mode image, that is, the region of the structure to the storage circuit 25. The estimated position of the structure is used in the tissue property analysis function and the waveform display function.

The method for estimating the structure using the received signal and the B-mode data for quantifying attenuation is not limited to the above-mentioned method. For example, the structure estimation function may use an putative signal (or image) extraction technique called CFAR processing. The term CFAR processing is used in the radar field. In this embodiment, the phrase "CFAR" is used for convenience in order to make the explanation more specific by its relevance. However, we are not bound by the methods used in the radar field or the rigorous use of statistics.

The CFAR process is executed, for example, by the following procedures (1) to (3).
(1) The control circuit 29 that realizes the setting function 291 sets a determination region having pixels in the vicinity of the pixel Pi for each pixel Pi of interest in the attenuated B mode image. The determination region set as a neighboring pixel by the control circuit 29 is provided in a cross shape in the attenuation B mode image. However, the arrangement of neighboring pixels in the set determination region is not restricted to a cross shape, and if, for example, the time required for arithmetic processing does not matter, a determination of an arbitrary size except for 8 pixels adjacent to the pixel of interest is determined. It may be an area.

The control circuit 29 that realizes the estimation function 292 calculates the brightness average value (or pixel average value) in the set determination region. At this time, in order to prevent the brightness value (or pixel value) of the pixel of interest from affecting the average value, the control circuit 29 may not include the pixel of interest Pi itself in the brightness average calculation.

(2) Next, the control circuit 29 subtracts the average value from the pixel value of the pixel of interest Pi. The control circuit 29 defines this subtraction value as the calculation result Ki for the position of the pixel of interest Pi and stores it in the storage circuit 25. The control circuit 29 executes this arithmetic processing for all the pixels of interest Pi.

(3) The control circuit 29 reads a preset threshold value T from the storage circuit 25. At this time, the threshold value T corresponds to the structure determination threshold value and is generally a value different from the structure determination threshold value corresponding to the normalized local variance Rσ. The control circuit 29 compares the calculation result Ki with the threshold value T. When Ki ≧ T, the pixel of interest Pi is displayed using the original brightness (extraction of the structure). On the other hand, when Ki <T, the brightness value of the pixel of interest Pi is set to zero and is not displayed (removal of the structure). By executing these processes for all the pixels of interest Pi, the CFAR process for the image can be executed.

In the determination of (3) above, when Ki ≧ T, the brightness is set to Ki and the pixel of interest Pi is displayed, and when Ki <T, the brightness value of the pixel of interest Pi is set to zero. It may not be displayed.

Further, the structure estimation function more simply includes an average value (or pixel value) of brightness values (or pixel values) in a plurality of regions set in a normal B-mode image, a dispersion value, a standard deviation value, and the like, and these values. The position of the structure may be estimated by comparing with the threshold value for determining the structure corresponding to each.
(Waveform information display function)
Next, the waveform information display function provided in the analysis device 2 according to the present embodiment will be described. The waveform display function calculates the physical quantity (feature quantity) obtained from the waveform of the received ultrasonic wave (echo signal) used in the analysis for each depth when the tissue property analysis using the ultrasonic image is performed. The information (waveform information) obtained by the above is displayed in a predetermined form. In addition, in this embodiment, in order to make the explanation concrete, a case where the attenuation amount of the ultrasonic wave propagating in the subject is analyzed as an example of the tissue property will be taken as an example.

FIG. 2 is a flowchart for explaining an analysis process including execution of the waveform information display function. As shown in the figure, in step S201, the control circuit 29 executes the tissue property analysis in response to the instruction from the user. As a result of the tissue property analysis, the B-mode image used for the analysis, and the decay image obtained as the analysis result (a color map showing the amount of attenuation at each position by hue, or a superimposed image of the color map and the B-mode image). Etc.) is displayed on the monitor 7. The method of tissue property analysis is not particularly limited. The typical method of tissue property analysis is as described above.

In step S202, the control circuit 29 that realizes the setting function 291 sets the ROI on the attenuated image. Specifically, the input device 5 inputs the ROI position and size confirmation instruction on the attenuated image displayed on the monitor 7 according to the user's operation via an interface such as a trackball or a panel button. The control circuit 29 that realizes the display control function 298 causes the ROI to be displayed on the medical image displayed on the monitor 7 in response to the user's measurement start instruction via the input device 5. The control circuit 29 that realizes the setting function 291 sets an ROI of a predetermined size at a predetermined position on the attenuated image in response to a confirmation instruction of the user via the input device 5.

In step S203, the control circuit 29 that realizes the estimation function 292 estimates the structure region and the uniform region in the ROI. The method for estimating the structure region and the uniform region in this step is not particularly limited. The typical estimation method is as described above as "structure estimation function".

In step S204, the control circuit 29 that realizes the waveform information generation function 297 excludes the structure region from the echo signals at each position in the ROI before the gain correction of the B mode image used for the tissue property analysis. Waveform information is generated using the echo signal corresponding to the uniform region. More specifically, in the control circuit 29 that realizes the waveform information generation function 297, the control circuit 29 that realizes the waveform information generation function 297 uses ultrasonic waves for the intensity (for example, luminance value) of the echo signal for each depth. Waveform information is generated by calculating statistical values (mean value, median value, maximum value, minimum value, etc.) in the scanning direction. At this time, at each depth, echo signals of all beams may be used, or beams selected at regular intervals in the scanning direction (discrete beams) are used to calculate statistical values in the ultrasonic scanning direction. You may.

The waveform information may be calculated using the amount of change in the echo signal (for example, the attenuation factor) without being bound by the intensity of the echo signal. The attenuation factor of the echo signal is, for example, the average value or median value after calculating the attenuation factor of each beam, or the brightness after processing after performing a process of taking the average value or median value of the brightness value of each beam. The damping factor may be calculated by obtaining the damping factor for the distribution. Further, the echo signal may be a signal obtained by canceling the adjustment amount by the gain adjustment after the gain adjustment according to the depth direction of the subject P such as the attenuation data described above. This echo signal may be obtained, for example, by restoring the pure intensity of the ultrasonic signal in the depth direction by the gain inverse correction function 293 described above. When a position in the directional direction is specified, waveform information may be generated from the echo signal at the position.

In step S205, the control circuit 29 that realizes the display control function 298 controls the image synthesizing unit 23 and the monitor 7 so that the generated waveform information is displayed in a predetermined form.

FIG. 3 is a diagram showing an example of waveform information displayed on the monitor 7. In the figure, the image on the left is a B-mode medical image 301 showing a cross section of the liver of subject P. The image on the right is an attenuated superimposed image in which the attenuated image 302 is superimposed on the B-mode medical image 301 of the subject. The difference in hatching in FIG. 3 corresponds to the difference in hue. In FIG. 3, there are three types of hues so that the attenuated superimposed image can be easily illustrated, but in reality, substantially continuous hues are displayed on the monitor 7 together with the legend. Further, the ROI 303 specified by the user is displayed in the attenuation superimposed image. The size of the ROI 303 may be the entire region of the attenuated image 302 or may be set independently of the attenuated image 302.

Further, along with the attenuated image 302, the waveform information 304 is displayed along the depth direction of the subject in the ROI 303. In FIG. 3, the waveform information 304 is referred to as "a physical quantity (intensity or change amount) obtained from the waveform of the echo signal for each depth in ROI 303" and "an axis and depth indicating the intensity or change amount of the echo signal". Is illustrated as an axis indicating. Therefore, the upper and lower ends of the waveform information 304 in the depth direction correspond to the upper and lower ends of the ROI 303 in the depth direction. Further, since the waveform information 304 is displayed so as to increase in the right direction when the intensity or the amount of change of the echo signal is large, it is displayed so as to be tilted from the right side to the left side of the screen along the depth direction.

The display form of the waveform information shown in FIG. 3 is merely an example, and various modifications can be made. For example, the height direction of the waveform information may be opposite as long as the waveform 304 and the ROI 303 have a corresponding relationship in the depth direction. Further, the "axis indicating the intensity or change amount of the echo signal and the axis indicating the depth" may be hidden as necessary, or the waveform information 304 may be displayed independently. Further, the intensity or amount of change of the echo signal may be displayed only for the depth at predetermined intervals (that is, discretely rather than continuously in the depth direction).

(Modification example 1)
Next, a modification 1 of the display mode of the waveform information will be described with reference to FIG.

FIG. 4 is a diagram showing an image of ROI 401 and waveform information 402 (the axis is not displayed) corresponding to ROI 401.

Here, the section information 405 and the section information 406, which are the sections corresponding to the estimated structure area 403 and the structure area 404 (hereinafter, referred to as section information) in the waveform information, are sections corresponding to the uniform area. The display mode is different from the information. In the example of FIG. 4, the display control function 298 controls the display so that the line type of the section information 405 and the section information 406 is a “broken line” and the section information corresponding to the other uniform area is a “solid line”. To distinguish the display mode. In addition, not only changing the line type, but also changing the color and line thickness, or combining at least one change of line type, color and line thickness, etc., in the structure area and the uniform area. The display mode may be different.

As a result, the user can see the different display modes of the waveform to determine whether the ROI is a region in which the echo signal is simply processed in the beam direction or a region in which the echo signal is processed by the echo signal excluding the echo signal in the structure region. Easy to grasp.

(Modification 2)
Next, a modified example 2 of the display mode of the waveform information will be described with reference to FIG.

FIG. 5 is a diagram showing the attenuation image in the ROI 401 and the waveform information 402 corresponding to the ROI 401, as in the case of FIG.

Even if there is a structure at a certain position in the depth direction of the subject, the structure area occupies a small proportion when considered in the scanning direction (directional direction), and the echo signal of the structure area is used in the generation of waveform information. It may not be necessary to remove it. In such a case, the ratio of the structure region to the ROI is calculated for each depth, and if the ratio of the structure region is less than a predetermined value, the section information corresponding to the structure region is displayed in the same display mode as the uniform region. If the ratio of the structure region is equal to or more than a predetermined value, the section information corresponding to the depth of the structure region ratio of the predetermined value or more and the other section information may be displayed in different display modes.
The waveform information 402 in the second modification may be waveform information generated by using an echo signal corresponding to a uniform region excluding the structure region among the echo signals at each position in the ROI, or the structure. It may be a waveform signal generated from an echo signal in ROI without excluding a region.

Specifically, for example, the control circuit 29 that realizes the estimation function 292 determines the number of pixels included in the ROI as the area of the ROI. The control circuit 29 compares the normalized local dispersion value calculated in the ROI with the threshold value for the variance for determining the structure (structure determination threshold value), and corresponds to the normalized local dispersion value larger than the structure determination threshold value. The number of pixels is determined as the area of the structure in the measurement ROI. The control circuit 29 calculates whether or not the ratio of the area of the region determined by the depth and the scanning direction to the area of the structure in the depth direction of the subject P is less than the threshold value, thereby occupying the ratio of the structure region. Should be calculated. The display control function 298 may perform the above-mentioned calculation / determination instead of the estimation function 292.

In the example of FIG. 5, it is assumed that the estimation function 292 determines that the structure region 501 has a ratio below the threshold value and the structure region 502 has a ratio greater than the threshold value. In this case, the display control function 298 displays the section information 503 corresponding to the structure region 501 with a solid line similar to the uniform area, and the section information 504 corresponding to the structure area 502 is thicker than the line of the uniform area. It is displayed so as to be (thick line 505). Here, as a different display mode, a case where the line thickness is changed is shown, but as in the case of FIG. 4, the display mode different between the section information corresponding to the structure region and the section information corresponding to the uniform region. It should be.

(Modification example 3)
Next, a third example of the display mode of the waveform information will be described with reference to FIG.

FIG. 6 shows a case similar to that of FIG. 5, except that the section information corresponding to the structure region is hidden from the waveform information 402. Specifically, the display control function 298 controls so that the section information 504 corresponding to the structure region 502 is hidden. The waveform information 402 is bent at the upper and lower ends of the structure region 502 because it connects the points where the value of the waveform information becomes zero, and the waveform may be displayed so as to be simply interrupted. In this way, an example of hiding the section information may be included as a different display mode.

In the present modification 3, the example in which the waveform information in the uniform region is mainly displayed has been described above, but the waveform information in the structure region may be mainly displayed without being bound by the example. The display control function 298 may control to generate waveform information based on the echo signal in the structure region and display the waveform based on the waveform information on the monitor 7. As the echo signal in the structure region, the received signal corresponding to the position determined as the structure may be used, and the B mode data for quantifying attenuation may be used.

Further, the image generation circuit 19 may generate an attenuated image in which the uniform region is hidden and only the structure region is extracted to give a hue as the attenuated image. The display control function 298 may display the attenuated image of the structure region and the waveform information of the structure region on the monitor 7.

FIG. 7 shows an example of a waveform display mode based on the structure region. In the example of FIG. 7, waveform information (section information 703 and section information 704) is generated based on the estimated echo signals in the structure area 701 and the structure area 702. In this way, when it is desired to pay attention to the structure area, the structure area can be emphasized and displayed.

According to the analysis device according to the present embodiment shown above, for example, in an attenuation superimposed image, when the user grasps the degree of attenuation indicating the organizational properties in the region corresponding to the position of the structure, the waveform based on the waveform information is obtained. It is also displayed. As a result, by additionally presenting auxiliary information to the user and assisting the user's visual judgment on the image, the user matches the objectivity by the attenuation value with the subjectivity by the appearance (luminance information). Is possible.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist 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 the equivalent scope thereof.

1 ... Ultrasonic diagnostic device, 3 ... Ultrasonic probe, 5 ... Input device, 7 ... Monitor, 9 ... Device body, 11 ... Ultrasonic transmission circuit, 13 ... Ultrasonic reception circuit, 15 ... B mode processing circuit, 17 ... Doppler processing circuit, 19 ... image generation circuit, 21 ... image memory, 23 ... image synthesis circuit, 25 ... storage circuit, 27 ... interface circuit, 29 ... control circuit (CPU), 111 ... pulse generator, 113 transmission delay circuit, 115 ... pulsar circuit, 131 ... preamp, 133 ... reception delay circuit, 135 ... adder, 291 ... setting function, 292 ... estimation function, 293 ... gain inverse correction function, 294 ... sound field characteristic correction function, 295 ... analysis function, 296 ... Acquisition function, 297 ... Waveform information generation function, 298 ... Display control function, 301 ... Medical image, 302 ... Damped image, 303,401 ... ROI, 304,402 ... Waveform, 405,406,503,504 ... Section information , 403,404,501,502,701,702 ... Structural area.

Claims (20)

An acquisition unit that acquires an echo signal based on ultrasonic scanning of a subject ,
A waveform generator for generating a waveform information from the echo signal,
A control unit for displaying a waveform based on waveform information in a second region different from the first region presumed to be a structure in the region of interest of the subject, and a control unit for displaying the waveform on the display unit.
An analyzer equipped with. The analysis device according to claim 1, wherein the waveform generation unit generates waveform information from echo signals in the second region excluding the first region. The analysis according to claim 1 or 2, wherein the waveform generation unit generates the waveform information by calculating the statistical value of the intensity of the echo signal in the second region for each depth of the subject. apparatus. The waveform generation unit generates the waveform information by calculating the statistical value of the amount of change in the intensity of the echo signal in the depth direction in the second region for each depth of the subject, claim 1. Alternatively, the analyzer according to claim 2. The control unit causes the display unit to display a waveform based on the waveform information in the section corresponding to the first region in a display mode different from the waveform based on the waveform information generated from the echo signal in the second region . The analyzer according to any one of claims 1 to 4. The control unit calculates the ratio of the first region to the region of interest for each depth.
The analysis device according to any one of claims 1 to 4 , wherein the display mode of the waveform differs between the portion corresponding to the depth of the predetermined value or more and the other portion. The analyzer according to claim 5 or 6 , wherein the display aspect includes at least one of a color, a line type, and a line thickness. Wherein, before Symbol section corresponding to the first region is controlled so as not to display information, the analysis apparatus according to any one of claims 1 to 7. A determination unit for determining the first region or the second region by analyzing a B-mode image of the subject is provided.
The analysis device according to any one of claims 1 to 8 , wherein the control unit displays the B-mode image together with the waveform. An image generation unit that generates an attenuated image indicating the degree of attenuation of the ultrasonic waves transmitted to the subject based on the echo signal is further provided.
The analysis device according to any one of claims 1 to 9 , wherein the control unit displays the attenuated image on the display unit together with the waveform. The echo signal according to any one of claims 1 to 10 , wherein the echo signal is acquired by canceling the adjustment amount by the gain adjustment after the gain adjustment according to the depth direction of the subject. Analyst. An input unit for designating a position in a region of interest or an azimuth direction with respect to an image representing the first region displayed on the display unit is provided.
The analysis device according to any one of claims 1 to 11 , wherein the waveform generation unit generates the waveform information from an echo signal in a position of interest or an azimuth direction designated by the input unit. An acquisition unit that acquires an echo signal based on ultrasonic scanning of a subject,
A waveform information generation unit that generates waveform information from the echo signal in the region of interest in the subject,
A control unit that calculates the ratio of a region estimated to be a structure to the region of interest for each depth and displays a waveform based on the waveform information on the display unit.
With
An analysis device in which the waveform display mode differs between a portion where the ratio corresponds to a depth of a predetermined value or more and another portion. An acquisition unit that acquires an echo signal based on ultrasonic scanning of a subject,
A waveform generation unit that generates waveform information from the echo signal of only the region presumed to be a structure in the region of interest of the subject.
A control unit that displays a waveform based on the waveform information on the display unit,
An analyzer equipped with. An acquisition unit that acquires an echo signal based on ultrasonic scanning of a subject,
An image generation unit that generates an attenuated image showing the degree of attenuation of the ultrasonic waves transmitted to the subject from the echo signal of only the region presumed to be a structure in the region of interest of the subject.
A control unit that displays the attenuated image on the display unit, and
An analyzer equipped with. An ultrasonic diagnostic apparatus including the analysis apparatus according to any one of claims 1 to 15. On the computer
Acquires an echo signal based on ultrasonic scanning of the subject,
Waveform information is generated from the echo signals in the second region excluding the first region presumed to be a structure in the region of interest of the subject.
An analysis program for displaying a waveform based on the waveform information on the display unit. On the computer
Acquires an echo signal based on ultrasonic scanning of the subject,
Waveform information is generated from the echo signal in the region of interest in the subject.
It is an analysis program for calculating the ratio of a region estimated to be a structure to the region of interest for each depth and displaying a waveform based on the waveform information on a display unit.
An analysis program in which the display mode of the waveform differs between a portion where the ratio corresponds to a depth of a predetermined value or more and another portion. On the computer
Acquires an echo signal based on ultrasonic scanning of the subject,
Waveform information is generated from the echo signal of only the region presumed to be a structure in the region of interest of the subject.
An analysis program for displaying a waveform based on the waveform information on the display unit. On the computer
Acquires an echo signal based on ultrasonic scanning of the subject,
From the echo signal of only the region presumed to be a structure in the region of interest of the subject, an attenuation image showing the degree of attenuation of the ultrasonic wave transmitted to the subject is generated.
An analysis program for displaying the attenuated image on the display unit.

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