Ultrasonic diagnostic equipment, ultrasonic diagnostic method and image processing apparatus

Abstract

To image periodicity of a change over time of a photographing target.SOLUTION: Ultrasonic diagnostic equipment according to an embodiment comprises a transmission and reception portion, an analysis portion, and a generation portion. The transmission and reception portion transmits ultrasonic waves into an analyte and receives echo signals with respect to the ultrasonic waves. The analysis portion extracts, at each space point, information on a motion velocity of an object within the analyte, included in a signal data row obtained from the echo signals. A calculation portion calculates periodical information of the motion of the analyte based on the extracted information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The embodiments disclosed in this specification and the drawings relate to an ultrasound diagnostic apparatus, an ultrasound diagnostic method, and an image processing apparatus. [Background technology]

[0002] Ultrasound diagnostic devices are equipped with many functions for blood flow imaging using the Doppler effect. Conventional ultrasound diagnostic devices can display, for example, the velocity and direction of blood flow, or the intensity of blood flow echoes.

[0003] However, if it were possible to image the periodicity of changes in hemodynamics over time, for example, the pattern of changes over the course of one heartbeat, various useful clinical applications could be envisioned, such as distinguishing between maternal and fetal blood flow and evaluating changes in renal hemodynamics associated with heart disease. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 114305 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to image the periodicity of changes over time of an object to be photographed. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0006] An ultrasound diagnostic device according to an embodiment includes a transmitting / receiving unit, an analyzing unit, and a generating unit. The transmitting / receiving unit transmits ultrasound waves into a subject and receives echo signals corresponding to the ultrasound waves. The analyzing unit extracts information on the motion speed of an object in the subject at each spatial point, the information being included in a signal data sequence obtained from the echo signals. The calculating unit calculates periodicity information of the motion of the subject based on the information. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of an ultrasonic diagnostic apparatus according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating the background according to the embodiment. [Diagram 3] FIG. 3 is a flowchart showing an example of processing performed by the ultrasound diagnostic apparatus according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating the configuration of an experiment performed by the ultrasound diagnostic apparatus according to the embodiment. [Diagram 5] FIG. 5 is a diagram illustrating the configuration of an experiment performed by the ultrasound diagnostic apparatus according to the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of data obtained by the ultrasound diagnostic apparatus according to the embodiment. [Figure 7] FIG. 7 is a diagram showing an example of data obtained by the ultrasound diagnostic apparatus according to the embodiment. [Figure 8] FIG. 8 is a flowchart showing an example of processing performed by the ultrasound diagnostic apparatus according to the second embodiment. [Figure 9] FIG. 9 is a flowchart showing an example of processing performed by the ultrasound diagnostic apparatus according to the third embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of processing performed by the ultrasound diagnostic apparatus according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (First embodiment) Hereinafter, embodiments of an ultrasound diagnostic apparatus, an ultrasound diagnostic method, and an image processing apparatus will be described in detail with reference to the drawings.

[0009] First, the configuration of an ultrasonic diagnostic device according to an embodiment will be described. Fig. 1 is a block diagram showing an example of the configuration of an ultrasonic diagnostic device according to an embodiment. As shown in Fig. 1, the ultrasonic diagnostic device according to an embodiment includes an ultrasonic probe 1, a monitor 2, an input device 3, and a device main body 10.

[0010] The ultrasonic probe 1 is connected to the device body 10 in order to transmit and receive ultrasonic waves. The ultrasonic probe 1 has, for example, a plurality of piezoelectric vibrators. These piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission / reception circuit 11 included in the device body 10. For example, the plurality of piezoelectric vibrators transmit ultrasonic waves to the subject P with an intensity corresponding to the magnitude of the voltage applied from the transmission / reception circuit 11. The plurality of piezoelectric vibrators included in the ultrasonic probe 1 also receive reflected waves (echoes) from the subject P, convert the received reflected waves into electrical signals (reflected wave signals), and transmit the reflected wave signals to the device body 10. The ultrasonic probe 1 also has a matching layer provided on the piezoelectric vibrator, a backing material that prevents the propagation of ultrasonic waves backward from the piezoelectric vibrator, and the like. The ultrasonic probe 1 is detachably connected to the device body 10.

[0011] When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are successively reflected by discontinuous surfaces of acoustic impedance in the internal tissues of the subject P, and are received as reflected waves by multiple piezoelectric transducers of the ultrasonic probe 1. The amplitude of the received reflected waves depends on the difference in acoustic impedance at the discontinuous surfaces where the ultrasonic waves are reflected.

[0012] The embodiment is applicable whether the ultrasonic probe 1 is a 1D array probe that scans the subject P two-dimensionally, or a mechanical 4D probe or a 2D array probe that scans the subject P three-dimensionally.

[0013] The input device 3 is realized by a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, a joystick, etc. The input device 3 receives various setting requests from an operator of the ultrasound diagnostic device, and transfers the received various setting requests to the device main body 10.

[0014] The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasound diagnostic device to input various setting requests using the input device 3, and displays ultrasound images and the like indicated by ultrasound image data generated in the device body 10. The monitor 2 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, or the like.

[0015] The device main body 10 is a device that generates ultrasonic image data based on a reflected wave signal transmitted from the ultrasonic probe 1. The device main body 10 shown in Fig. 1 is a device that can generate two-dimensional ultrasonic image data based on a two-dimensional reflected wave signal, and can generate three-dimensional ultrasonic image data based on a three-dimensional reflected wave signal.

[0016] As shown in FIG. 1, the device main body 10 includes a transmission / reception circuit 11, a buffer 12, a B-mode processing circuit 13, an image generation circuit 15, an image memory 16, an internal storage circuit 17, and a processing circuit 18.

[0017] The transmission / reception circuit 11 controls the ultrasonic scanning performed by the ultrasonic probe 1 based on instructions from the processing circuit 18 described later. Note that ultrasonic scanning refers to, for example, ultrasonic transmission and reception. The transmission / reception circuit 11 has a pulse generator, a transmission delay circuit, a pulser, etc., and supplies a drive signal to the ultrasonic probe 1. The pulse generator repeatedly generates rate pulses for forming a transmission ultrasonic wave at a predetermined repetition frequency (PRF: Pulse Repetition Frequency). In addition, the transmission delay circuit focuses the ultrasonic waves generated from the ultrasonic probe 1 into a beam shape and provides a delay time for each piezoelectric transducer required to determine the transmission directivity to each rate pulse generated by the pulse generator. In addition, the pulser applies a drive signal to the ultrasonic probe 1 at a timing based on the rate pulse. That is, the transmission delay circuit arbitrarily adjusts the transmission direction of the ultrasonic waves transmitted from the piezoelectric transducer surface by changing the delay time provided to each rate pulse.

[0018] For example, the transmission / reception circuitry 11 causes the ultrasound probe 1 to perform ultrasound scanning to collect data sequences between frames as Doppler data sequences under the control of the processing circuitry 18. As an example, the ultrasound probe 1 and the transmission / reception circuitry 11 collect reflected wave data from the same position over multiple frames in the time direction to collect a data sequence of reflected wave data from the same position.

[0019] The transmission / reception circuit 11 has an amplifier circuit, an A / D (Analog / Digital) converter, a reception delay circuit, an adder, a quadrature detection circuit, etc., and performs various processes on the reflected wave signal transmitted from the ultrasonic probe 1 to generate reflected wave data. The transmission / reception circuit 11 then stores the generated reflected wave data in a buffer 12. The amplifier circuit amplifies the reflected wave signal for each channel and performs gain correction processing. The A / D converter A / D converts the gain-corrected reflected wave signal. The reception delay circuit provides the digital data with a reception delay time required to determine the reception directivity. The adder performs addition processing of the reflected wave signal to which the reception delay time has been provided by the reception delay circuit. The addition processing of the adder emphasizes the reflected component from the direction according to the reception directivity of the reflected wave signal. The process of performing phase adjustment by reception delay for each reflected wave signal of each element and adding them is also called phasing addition processing or beamforming processing.

[0020] The quadrature detection circuit converts the output signal of the adder into an in-phase signal (I signal, I: In-phase) and a quadrature signal (Q signal, Q: Quadrature-phase) in the baseband. The quadrature detection circuit then stores the I signal and Q signal (hereinafter referred to as IQ signal) in the buffer 12 as reflected wave data.

[0021] The buffer 12 is a memory that temporarily stores the reflected wave data generated by the transmission / reception circuit 11. Specifically, the buffer 12 stores several frames of reflected wave data or several volumes of reflected wave data. For example, the buffer 12 is a first-in / first-out (FIFO) memory, and stores a predetermined number of frames of reflected wave data under the control of the transmission / reception circuit 11. Then, for example, when one frame of reflected wave data is newly generated by the transmission / reception circuit 11, the buffer 12 discards the oldest one frame of reflected wave data under the control of the transmission / reception circuit 11 and stores the newly generated one frame of reflected wave data. For example, the buffer 12 is realized by a semiconductor memory element such as a random access memory (RAM) or a flash memory.

[0022] The B-mode processing circuit 13 and the processing circuit 18 are signal processing units that perform various signal processing on the reflected wave data generated from the reflected wave signal by the transmission / reception circuit 11. The B-mode processing circuit 13 and the processing circuit 18 are realized by, for example, a processor. The B-mode processing circuit 13 reads out the reflected wave data from the buffer 12, and performs logarithmic amplification, envelope detection processing, logarithmic compression, etc. on the read out reflected wave data to generate data (B-mode data) in which the signal intensity of each of a plurality of sample points is expressed as luminance brightness.

[0023] The processing circuit 18 has an analysis function 18a, a calculation function 18b, a generation function 18c, a display control function 18d, and a control function 18e. Here, each processing function executed by the processing circuit 18 having the analysis function 18a, the calculation function 18b, the generation function 18c, the display control function 18d, and the control function 18e is recorded in the internal storage circuit 17 in the form of a program executable by a computer. The processing circuit 18 realizes a function corresponding to each program read out by reading out each program from the internal storage circuit 17 and executing it. In other words, the processing circuit 18 in a state in which each program has been read out has each function shown in the processing circuit 18 in FIG. 1.

[0024] Various processes of the analysis function 18a, the calculation function 18b, the generation function 18c, the display control function 18d, and the control function 18e will be described later. The analysis function 18a, the calculation function 18b, the generation function 18c, the display control function 18d, and the control function 18e are examples of an analysis unit, a calculation unit, a generation unit, a display control unit, and a control unit, respectively. The transmission / reception circuit 11 and the monitor 2 are examples of a transmission / reception unit and a display unit, respectively.

[0025] The processing circuitry 18 uses the analysis function 18a to read out the reflected wave data from the buffer 12, and performs frequency analysis on the read out reflected wave data to estimate motion information based on the Doppler effect of a moving object within the scanning range, and generate data (Doppler data) indicating the estimated motion information. For example, the processing circuitry 18 estimates the average velocity, average variance value, average power value, etc., as the motion information of the moving object at each of a plurality of sample points, and generates Doppler data indicating the estimated motion information. Here, the moving object is, for example, blood flow, tissue such as a heart wall, or a contrast agent.

[0026] Using the above-mentioned analysis function 18a, the ultrasonic diagnostic apparatus according to this embodiment can execute a color Doppler method, also called a color flow mapping (CFM) method. In the CFM method, ultrasonic waves are transmitted and received multiple times on multiple scanning lines. In the CFM method, a moving target indicator (MTI) filter is applied to a data sequence at the same position to suppress signals (clutter signals) originating from stationary tissue or slow-moving tissue and extract a blood flow signal originating from blood flow. For example, when a data sequence of reflected wave data at the same position is input to the MTI filter, the MTI filter outputs a blood flow signal in which clutter is suppressed and blood flow components are dominant. As the MTI filter, for example, an adaptive principal component analysis filter that changes coefficients according to an input signal is used.

[0027] Furthermore, the processing circuitry 18 calculates periodicity information of the subject's movement using the calculation function 18b. The processing circuitry 18 generates a spatial distribution of the periodicity information using the generation function 18c. The details of the calculation function 18b and the generation function 18c will be described later.

[0028] Furthermore, the processing circuit 18 controls the display of the monitor 2 by a display control function 18d.

[0029] The processing circuitry 18 controls the overall processing of the ultrasonic diagnostic apparatus by the control function 18e. Specifically, the processing circuitry 18 controls the processing of the transmission / reception circuitry 11, the B-mode processing circuitry 13, the Doppler processing circuitry 14, and the image generating circuitry 15 based on various setting requests input by the operator via the input device 3 and various control programs and various data read from the internal storage circuitry 17. For example, the processing circuitry 18 controls the ultrasonic probe 1 via the transmission / reception circuitry 11 to control ultrasonic scanning.

[0030] The image generating circuitry 15 generates ultrasound image data from the data generated by the B-mode processing circuitry 13 and the processing circuitry 18 .

[0031] Here, the image generating circuit 15 generally converts (scan converts) a scan line signal sequence of ultrasonic scanning into a scan line signal sequence of a video format represented by a television or the like, and generates ultrasonic image data for display. Specifically, the image generating circuit 15 generates ultrasonic image data for display by performing coordinate conversion according to the ultrasonic scanning form of the ultrasonic probe 1. In addition to scan conversion, the image generating circuit 15 also performs various image processing, such as image processing (smoothing processing) for regenerating an average brightness image using multiple image frames after scan conversion, and image processing (edge ​​enhancement processing) using a differential filter in the image. In addition, the image generating circuit 15 combines character information of various parameters, scales, body marks, etc. with the ultrasonic image data.

[0032] The image memory 16 is a memory that stores image data for display generated by the image generating circuit 15. The image memory 16 can also store data generated by the B-mode processing circuit 13 and the processing circuit 18.

[0033] The internal storage circuit 17 stores various data such as control programs for performing ultrasonic transmission / reception, image processing, and display processing, diagnostic information (e.g., patient ID, doctor's findings, etc.), diagnostic protocols, and various body marks. The internal storage circuit 17 is also used for storing image data stored in the image memory 16 as necessary. The data stored in the internal storage circuit 17 can be transferred to an external device via an interface (not shown). The internal storage circuit 17 can also store data transferred from an external device via an interface (not shown). For example, the internal storage circuit 17 is realized by a semiconductor memory element such as a flash memory, a hard disk, or an optical disk.

[0034] Note that the image processing device according to the embodiment may be configured, for example, by the image generating circuit 15, the image memory 16, the internal storage circuit 17, the monitor 2, and the input device 3. The image processing device according to the embodiment may be incorporated in an ultrasonic diagnostic device, or may be configured as an image processing device independent of the ultrasonic diagnostic device.

[0035] Next, the background of the embodiment will be described.

[0036] Ultrasound diagnostic devices are equipped with many functions for blood flow imaging using the Doppler effect. Specifically, conventional ultrasound diagnostic devices can display the velocity, direction, or blood flow echo intensity of blood flow.

[0037] In addition, the ultrasonic diagnostic device according to the embodiment is intended to image the periodicity of the change over time of the hemodynamics, i.e., the pattern of the change over time of, for example, about one heartbeat. Imaging the periodicity of the change over time of the hemodynamics is considered to be useful, for example, in distinguishing between the blood flows of the mother and the fetus, and in evaluating the change in renal hemodynamics associated with heart disease.

[0038] A first application example of imaging the periodicity of time-dependent changes in hemodynamics is, for example, the identification of maternal-fetal blood flow. FIG. 2 shows a schematic diagram of fetal blood vessels and maternal blood flow in the placenta. The umbilical blood vessels 20 are fetal blood vessels, which are connected to the fetal side through the umbilical cord 22 and obtain oxygen and nutrients from the intervillous space 21, which is a pool of maternal blood, through the villi 25. Here, it is important in evaluating placental function that the villi 25 are sufficiently constructed (fetal blood vessels) and that blood vessels branching from the uterine artery 24 reach the villous lumen 21 sufficiently (maternal blood vessels). To confirm these, it is necessary to identify whether the villous lumen 21 and the microvessels present around it are maternal blood vessels or fetal blood vessels. However, since the umbilical blood vessels 20, the villi 25, and the maternal blood flow are adjacent to each other, it is difficult to identify the maternal-fetal blood flow.

[0039] Therefore, in the ultrasonic diagnostic device according to the embodiment, the processing circuitry 18 calculates periodicity information of the subject's motion and generates a spatial distribution of the periodicity information. Here, in the umbilical cord blood vessels 20, blood circulates based on the period of the fetal heartbeat, whereas in the maternal blood vessels, blood circulates based on the period of the maternal heartbeat, so that the fetal blood vessels and the maternal blood vessels have different motion frequencies. Therefore, the processing circuitry 18 calculates periodicity information of the subject's motion and generates a spatial distribution of the periodicity information, thereby making it possible to identify the maternal-fetal blood flow.

[0040] A second application example of imaging the periodicity of time-dependent changes in hemodynamics is, for example, identification of time-dependent changes in intrarenal hemodynamics to evaluate deterioration of renal hemodynamics associated with heart disease, i.e., cardiorenal correlation. In particular, the blood flow pattern of the intrarenal interlobar vein is known to be strongly correlated with the prognosis of heart failure. Specifically, the blood flow pattern of the interlobar vein of a heart disease patient is monophasic or biphasic, and cases have been reported in which the prognosis is poorer in the case of monophasic blood flow than in the case of biphasic blood flow. Therefore, it is conceivable that the processing circuit 18 can calculate, for example, periodicity information of time-dependent changes in blood flow in the interlobar vein, and use the information to predict the prognosis of heart failure.

[0041] In view of such problems, the ultrasound diagnostic apparatus according to the embodiment includes a transmission / reception circuit 11 as a transmission / reception unit, and a processing circuit 18. The transmission / reception circuit 11 transmits ultrasound into the subject and receives an echo signal corresponding to the ultrasound. The processing circuit 18 extracts, at each spatial point, information on the motion speed of an object in the subject, which is included in a signal data sequence obtained from the echo signal, using an analysis function 18a. The processing circuit 18 calculates periodicity information of the subject's motion based on the information on the motion speed using a calculation function 18b. The processing circuit 18 generates a spatial distribution of the periodicity information using a generation function 18c. Here, the periodicity information is information related to the period of the motion of the subject, and examples thereof include a frequency spectrum obtained by Fourier transforming data obtained for each spatial point, and information on an average frequency obtained by averaging the frequency spectrum with respect to frequency.

[0042] Moreover, the ultrasound diagnostic method according to the embodiment transmits ultrasound into a subject, receives echo signals corresponding to the ultrasound, extracts information regarding the motion speed of an object inside the subject at each spatial point, which information is included in a signal data sequence obtained from the echo signals, calculates periodicity information of the subject's motion based on the information, and generates a spatial distribution of the periodicity information.

[0043] The image processing device according to the embodiment also includes a processing circuit 18. The processing circuit 18 extracts, at each spatial point, information on the motion speed of an object in the subject, which is included in a signal data sequence obtained from an echo signal corresponding to an ultrasound wave transmitted into the subject, using an analysis function 14a. The processing circuit 18 calculates periodicity information of the subject's motion based on the information using a calculation function 14b. The processing circuit 18 generates a spatial distribution of the periodicity information using a generation function 14c.

[0044] Details of such processing will be described with reference to Fig. 3. Fig. 3 is a flowchart showing the flow of processing executed by the ultrasonic diagnostic apparatus according to the first embodiment.

[0045] First, in step S100, the transmission / reception circuitry 11 as a transmission / reception unit transmits ultrasonic waves into the subject and receives echo signals corresponding to the ultrasonic waves. As an example, the transmission / reception circuitry 11 receives echo data over multiple frames using a plane wave compounding method. Note that the embodiment is not limited to receiving echo data using the plane wave compounding method, and the transmission / reception circuitry 11 may transmit and receive ultrasonic waves using other methods that scan a region of interest at a high frame rate, such as a transmit aperture synthesis method using focused ultrasonic transmission.

[0046] Next, in step S110, the processing circuitry 18 causes the analysis function 18a to perform beamforming on the echo signals received in step S100, to generate a signal data sequence.

[0047] Next, in step S120, the processing circuitry 18 uses the analysis function 18a to extract signals related to the object of the subject from the signal data sequence generated in step S110. As an example, the processing circuitry 18 uses the analysis function 18a to extract a blood flow signal from the signal data sequence generated in step S110. For example, the processing circuitry 18 uses the analysis function 18 to apply an MTI (Moving Target Indicator) filter to the signal data sequence generated in step S110 to extract the blood flow signal. As another example, the processing circuitry 18 uses the analysis function 18 to extract the blood flow signal using a wall motion filter method on the signal data sequence generated in step S110.

[0048] Next, in step S130, the processing circuitry 18 extracts, for each frame t, information s(t,x) on the motion velocity of an object in the subject at each spatial point x from a signal data sequence obtained from an echo signal by using the analysis function 18a as an analysis unit. As an example, the processing circuitry 18 calculates blood flow velocity from a blood flow signal in each frame by using the analysis function 18a, for example, an autocorrelation method or a Doppler spectrum method. That is, the processing circuitry 18 extracts, for each frame t, a time waveform of Doppler velocity as information s(t,x) on the motion velocity of an object in the subject from a data sequence obtained based on an echo signal by using the analysis function 18a, for example, an autocorrelation method or a Doppler spectrum method.

[0049] Next, in step S140, the processing circuit 18 uses the calculation function 14b to calculate the frequency spectrum S(i,x) of the blood flow velocity waveform at each spatial point x, where i is an index corresponding to the frequency in the frame direction.

[0050] As an example, the processing circuit 18 calculates a complex frequency spectrum S(i,x) for a plurality of frequencies f(i) by performing Fourier analysis on the information s(t,x) on the motion speed extracted at each spatial point x using the calculation function 14b. Here, f(i) represents a frequency in the frame direction, and represents, for example, a periodic fluctuation in the motion information of the object originating from the heartbeat. Hereinafter, the complex frequency spectrum S(i,x) obtained at each spatial point x will be simply referred to as S(i).

[0051] Next, in step S150, the processing circuitry 18 calculates, using the calculation function 14b as a calculation unit, periodicity information of the subject's motion based on information on the motion speed of the object in the subject in each space. As an example, the processing circuitry 18 calculates, using the calculation function 14b, an average frequency related to the time-dependent change in the motion of the object, for example, an average frequency of the blood flow speed, as periodicity information of the subject's motion, at each space point.

[0052] As an example, the processing circuit 18 uses the calculation function 14b as a calculation unit to add the frequency f(i) while weighting it using the magnitude of the frequency spectrum S(i) calculated in step S140, thereby calculating the average frequency μ f As an example, the processing circuit 18 calculates the average frequency μ by adding the frequency f(i) while weighting it using the magnitude of the frequency spectrum S(i) calculated in step S140 using the following formula (1): f is calculated as the periodicity information.

[0053]

number

[0054] Next, in step S160, the processing circuit 18 uses the generating function 14c as a generating unit to generate the average frequency μ f Based on the periodicity information of the subject's motion, the spatial distribution μ f Generate (x).

[0055] Next, in step S170, the processing circuit 18 causes the display control function 18d to display the generated spatial distribution of the frequency information on the display unit.

[0056] To supplement the individual processing for each application example, when the purpose is to identify maternal-fetal blood flow, the object in the subject is a region including umbilical blood vessels 20, and the processing circuit 18 calculates, by the calculation function 18b, information corresponding to the maternal heart rate for the intervillous space 21, which is a region corresponding to the maternal blood vessels, as first movement periodicity information, and calculates information corresponding to the fetal heart rate for the region corresponding to the umbilical blood vessels 20 as second movement periodicity information. For example, the processing circuit 18 sets threshold values ​​corresponding to the maternal heart rate and the fetal heart rate, respectively, by the calculation function 18b, and determines the region as maternal blood if the calculated movement periodicity information is within a numerical range defined for the maternal heart rate, and determines the region as fetal blood vessels if the calculated movement periodicity information is within a numerical range defined for the fetal heart rate.

[0057] In addition, when the purpose is to distinguish between single-phase and two-phase of interlobar venous blood flow for cardiac-renal linkage analysis, the object in the subject is a region including intrarenal interlobar vein, and the processing circuitry 18 calculates periodicity information of blood flow in the intrarenal interlobar vein by the calculation function 18b, and generates information on the state of cardiac disease based on the calculated periodicity information of blood flow in the intrarenal interlobar vein. As an example, the processing circuitry 18 determines, by the calculation function 18b, that if the periodic pattern of blood flow in the intrarenal interlobar vein is single-phase, the risk of cardiac disease state becoming poor is high, and if it is two-phase, the risk of cardiac disease becoming poor is relatively low.

[0058] Furthermore, for example, when imaging blood flow in the brain, for example, by imaging the spatial distribution of periodicity information for each direction of motion of the object, it is possible to perform high-sensitivity blood flow imaging. As an example, in step S120, the processing circuit 18 extracts signals included in the signal data string for each direction of motion of the object by the analysis function 14a, and generates a spatial distribution of periodicity information for each direction of motion of the object by the calculation function 18b.

[0059] In order to verify the effectiveness of the method according to the first embodiment, an ultrasonic measurement experiment was performed using a phantom containing a scattering fluid. FIG. 4 and FIG. 5 are schematic diagrams showing an outline of such an ultrasonic measurement experiment. FIG. 4 shows a cross-sectional view of the scattering fluid 31 in the flow path long axis direction, and a cross-sectional view of the scattering fluid 31 in the flow path short axis direction. In this ultrasonic measurement experiment, a phantom 33 containing a scattering fluid 31 was measured using an ultrasonic probe 1. The ultrasonic probe 1 performed the measurement using a plane wave compound scan with a transmission center frequency of 6 MHz. FIG. 4 and FIG. 5 show a measurement cross section 34 and a measurement region 32, respectively. The scattering fluid 31 was caused to flow in a pulsatile flow using a pump 30, and measurements were performed at pulsation periods of 0.5 Hz and 1 Hz.

[0060] 6 and 7 show the average frequency (spatial distribution μ f FIG. 6 shows the spatial distribution μ of frequency information when the pulsation period of the pulsation flow by the pump 30 is 0.5 Hz, and FIG. 7 shows the spatial distribution μ of frequency information when the pulsation period of the pump 30 is 1 Hz. f 6 and 7, the average frequency is located near 0.5 Hz and 1 Hz, respectively. f It was confirmed that (x) could be calculated roughly correctly.

[0061] As described above, in the first embodiment, the processing circuitry 18 calculates periodicity information of the subject's movement using the calculation function 18b, and generates a spatial distribution of the periodicity information using the generation function 18c. This makes it possible to image the periodicity of the time-dependent change of the subject.

[0062] Second embodiment In the first embodiment, a case where the time waveform of the Doppler velocity is extracted as information s(t,x) relating to the motion velocity of an object in the subject in step S130 has been described. However, the embodiment is not limited to this. In the second embodiment, a case where the echo signal intensity after application of the MTI filter is extracted as information relating to the motion velocity of an object in the subject will be described.

[0063] 8 is a flowchart showing the flow of processing performed by an ultrasonic diagnostic apparatus according to the second embodiment. The processing other than steps S130A to S150A is the same as in FIG. 3, so repeated explanation will be omitted.

[0064] In step S130A, the processing circuitry 18 extracts, for each frame t, information s(t, x) on the motion velocity of an object in the subject, which is included in a signal data sequence obtained from an echo signal, at each spatial point x, using the analysis function 18a as an analysis unit. Here, in the second embodiment, the processing circuitry 18 extracts, instead of the time waveform of the Doppler velocity, the echo signal intensity after the application of the MTI filter applied in step S120, as information on the motion intensity, using the analysis function 18a. The processing circuitry 18 extracts, for each frame t, the echo signal intensity from the data sequence obtained based on the echo signal, as information s(t, x) on the motion velocity of an object in the subject, using the analysis function 18a.

[0065] Here, the significance of extracting the echo signal intensity as information s(t,x) on the motion velocity of an object inside a subject will be explained. Since the echo signal intensity after the MTI filter is applied increases in proportion to the blood flow velocity, by frequency analyzing the echo signal intensity instead of the velocity waveform, it is possible to obtain an effect similar to that obtained by frequency analyzing the velocity waveform. Furthermore, since the echo signal intensity is not subject to accuracy degradation due to aliasing, analyzing the echo signal intensity can suppress accuracy degradation due to aliasing compared to the velocity waveform.

[0066] Next, in step S140, the processing circuitry 18 calculates the frequency spectrum S(i,x) of the echo signal intensity waveform at each spatial point x using the calculation function 14b. As an example, the processing circuitry 18 calculates the complex frequency spectrum S(i,x) for a plurality of frequencies f(i) by performing Fourier analysis on the echo signal intensity, which is information s(t,x) on the motion speed extracted at each spatial point x using the calculation function 14b.

[0067] Next, in step S150, the processing circuitry 18 uses the calculation function 14b as a calculation unit to calculate periodicity information of the subject's motion in each space based on information on the motion speed of the object in the subject. As an example, the processing circuitry 18 uses the calculation function 14b to calculate the average frequency of the echo signal intensity waveform in each space point as periodicity information of the subject's motion.

[0068] As an example, the processing circuit 18 uses the calculation function 14b to add the frequency f(i) while weighting it using the magnitude of the frequency spectrum S(i) calculated in step S140, thereby calculating the average frequency μ f is calculated as the periodicity information.

[0069] As described above, in the second embodiment, the processing circuit 18 performs frequency analysis using the blood flow echo intensity instead of the blood flow velocity waveform by the calculation function 18b, and generates a spatial distribution of periodicity information. The second embodiment is an alternative embodiment to the first embodiment, and by using the blood flow echo intensity instead of the velocity waveform, it is possible to suppress deterioration of accuracy due to aliasing.

[0070] (Third embodiment) In the first embodiment, in step S150, the periodicity information of the subject's movement is calculated using the frequency spectrum in the entire frequency range. In the third embodiment, the processing circuit 18 calculates the average frequency in a limited frequency band as the periodicity information by the calculation function 18b. This makes it possible to improve the accuracy of the calculated periodicity information.

[0071] A flow of processing performed by an ultrasonic diagnostic apparatus in the third embodiment is shown in Fig. 9. Processing other than step S150B is similar to that in Fig. 3, so repeated explanation will be omitted.

[0072] In step S150B, the processing circuitry 18, using the calculation function 14b as a calculation unit, limits a band of interest (frequency) in each space and calculates periodicity information of the subject's motion based on information on the motion speed of the object in the subject. As an example, the processing circuitry 18, using the calculation function 14b, limits a band of interest in each space point and calculates an average frequency related to the time-dependent change in the motion of the object in the limited frequency band, for example, an average frequency of the blood flow speed, as periodicity information of the subject's motion.

[0073] Specifically, the processing circuit 18 uses the calculation function 14b as a calculation unit to add the frequency f(i) while weighting it using the magnitude of the frequency spectrum S(i) calculated in step S140, thereby calculating the average frequency μ′ f As an example, the processing circuit 18 uses the calculation function 14b to calculate the average frequency μ′ by adding the frequency f(i) while weighting it using the magnitude of the frequency spectrum S(i) calculated in step S140 using the following formula (2): f is calculated as the periodicity information.

[0074]

number

[0075] Here, i1 and i2 are indices corresponding to the lower and upper limit frequencies of the band of interest, and the frequency band from f(i1) to f(i2) corresponding to the value of i, which is an index representing frequency, being from i1 to i2 is the limited frequency band used to calculate the average frequency.

[0076] Here, the reason why the lower limit frequency i1 of the band of interest is set is that stationary components with a frequency near 0 become a hindrance in calculating the average frequency. That is, the processing circuit 18 can increase the accuracy of calculating the average frequency by using the calculation function 18b to limit the frequency band to the frequency band equal to or higher than the lower limit frequency i1 and calculating the change over time in the motion of the object.

[0077] The reason for setting the upper limit frequency i2 of the band of interest is to improve the accuracy of calculating the average frequency by removing signal components other than the frequency band of interest. That is, a clinically important frequency band is, for example, a frequency band corresponding to a pulsation period, and the processing circuit 180 and the calculation function 14b can improve the accuracy of calculating the average frequency by removing a frequency band that is significantly different from the frequency band corresponding to the pulsation period from the calculation of the average frequency.

[0078] As described above, in the third embodiment, the processing circuitry 18 limits the band of interest and calculates the periodicity information of the subject's movement by the calculation function 18b. This makes it possible to obtain the periodicity information of the subject's movement with higher accuracy.

[0079] (Fourth embodiment) In the above embodiments, periodicity information of the time-dependent change in the motion of the object in the subject is calculated. The embodiments are not limited to these. In the fourth embodiment, the processing circuit 18 further calculates information on the stationary component of the time-dependent change in the motion of the object in the subject by the calculation function 18b. This makes it possible to analyze the object in the subject not only on the periodicity information but also on the stationary component, and for example, by distinguishing between veins and arteries, which are stationary flows, and extracting only the arteries, the accuracy of diagnosis is improved.

[0080] 10 is a flowchart showing the flow of processing executed by an ultrasonic diagnostic apparatus according to the fourth embodiment. Here, the processing other than steps S150B to S170 is common to the first embodiment, and therefore will not be described again.

[0081] As in the first embodiment, in step S140, the processing circuit 18 calculates the frequency spectrum S(i,x) of the blood flow velocity waveform at each spatial point x using the calculation function 18b. As in the third embodiment, in step S150B, the processing circuit 18 uses the calculation function 14b as a calculation unit to limit the band of interest in each space and calculate periodicity information of the subject's movement based on information related to the movement speed of the object in the subject.

[0082] As an example, the processing circuit 18 uses the calculation function 14b to limit the band of interest to a second region at each spatial point and calculates an average frequency related to the time-dependent change in the motion of the object in the limited frequency band, for example, an average frequency of blood flow velocity, as periodicity information of the motion of the subject. Specifically, the processing circuit 18 uses the calculation function 14b to add the frequency f(i) to the second region, which is a frequency band between the lower limit frequency i1 and the upper limit frequency i2, while weighting the frequency f(i) using the magnitude of the frequency spectrum S(i) calculated in step S140, using equation (2), thereby calculating the average frequency μ' f is calculated as the periodicity information.

[0083] Meanwhile, in step S150C, the processing circuitry 18 further calculates information on a stationary component (DC component) of the motion of the object in the subject by using the calculation function 18b. Specifically, the processing circuitry 18 limits the band of interest at each spatial point to a first region in which the frequency is equal to or higher than 0 and equal to or lower than a threshold frequency i, and calculates the frequency dispersion on the motion of the object in the subject as periodicity information of the motion of the subject by using the calculation function 18b. Since the frequency dispersion means the concentration degree of the signal intensity on the DC component, in step S150C, the processing circuitry 18 can evaluate the stationary component on the motion of the object in the subject by using the calculation function 18b.

[0084] In this manner, in the fourth embodiment, the processing circuit can use the calculation function 18b to calculate periodicity information of the subject's motion in step S150B and evaluate the stationary component in step S150C. This makes it possible to perform, for example, arteriovenous separation in the case of blood flow imaging and display periodicity information regarding blood flow.

[0085] Next, in step S160A, the processing circuit 18 uses the generating function 14c as a generating unit to generate the average frequency μ f Based on the periodicity information of the subject's motion, the spatial distribution μ' of frequency information is calculated. f Generate (x).

[0086] Next, in step S170, the processing circuit 18 causes the display control function 18d to display the generated spatial distribution of the frequency information on the monitor 2 serving as a display unit.

[0087] The processing circuit 18 and the calculation function 18b may further calculate an index representing the pulsatility of blood flow. As an example, the processing circuit 18 may further calculate a pulsatility index (PI) or a resistance index (RI) that is an index for evaluating peripheral vascular resistance as an index representing the pulsatility of blood flow by the calculation function 18b. Specifically, the processing circuit 18 calculates the pulsatility index (PI) by the calculation function 18b by dividing the difference between the peak systolic velocity (PSV) and the end diastolic blood velocity (EDV) by the time-averaged maximum blood velocity (TAMV). The processing circuit 18 can also calculate the resistance index (RI) by the calculation function 18b by obtaining a value obtained by dividing the difference between the peak systolic velocity (PSV) and the end diastolic blood velocity (EDV) by the peak systolic velocity (PSV).

[0088] In step S170, the processing circuitry 18 may control the monitor 2 as a display unit by using the display control function 14d to superimpose and display the periodicity information together with at least one of the following information: the index representing the pulsatility of the blood flow, the information on the stationary component of the time-dependent change in the motion of the object calculated in step S150C, and the information on the Doppler velocity calculated in step S130. As an example, the processing circuitry 18 may control the monitor 2 as a display unit by using the display control function 18d to display the at least one information using a first color bar and display the periodicity information calculated in step S150B using a second color bar.

[0089] According to at least one of the embodiments described above, it is possible to image the periodicity of the change over time of the subject to be imaged.

[0090] Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0091] 18 Processing circuit 18a Analysis Function 18b Calculation Function 18c generation function 18d Display control function

Claims

1. a transmitting / receiving unit that transmits ultrasonic waves into a subject and receives echo signals corresponding to the ultrasonic waves; an analysis unit that extracts information regarding a motion velocity of an object within the subject at each spatial point, the information being included in a signal data sequence obtained from the echo signals; A calculation unit that calculates periodicity information of the subject's motion based on the information; and A generation unit that generates a spatial distribution of the periodicity information; An ultrasound diagnostic device comprising:

2. The ultrasonic diagnostic apparatus according to claim 1 , wherein the analysis unit applies an MTI (Moving Target Indicator) filter to the signal data sequence and extracts information about a blood flow signal as information about the movement speed.

3. The ultrasonic diagnostic apparatus according to claim 1 , wherein the analysis unit extracts a time waveform of Doppler velocity as information related to the motion velocity.

4. The ultrasonic diagnostic apparatus according to claim 2 , wherein the analysis unit extracts echo signal intensity after application of the MTI filter as information related to the motion speed.

5. The ultrasound diagnostic apparatus according to claim 1 , wherein the calculation unit calculates an average frequency related to a change over time in the motion of the object as the periodicity information.

6. The ultrasonic diagnostic apparatus according to claim 5 , wherein the calculation unit calculates the average frequency in a limited frequency band as the periodicity information.

7. 6. The ultrasound diagnostic apparatus according to claim 5, wherein the calculation unit calculates frequency spectra for a plurality of frequencies by performing Fourier analysis on information related to the motion velocity extracted at each spatial point, and calculates the average frequency as the periodicity information by adding the frequencies while weighting them using the magnitude of the frequency spectrum.

8. The ultrasound diagnostic apparatus according to claim 1 , wherein the calculation unit further calculates information on a stationary component of a change over time in the motion of the object.

9. The ultrasonic diagnostic apparatus according to claim 1 , wherein the calculation unit further calculates a pulsatility index (PI) or a resistance index (RI) as an index representing the pulsatility of blood flow.

10. 2. The ultrasound diagnostic apparatus of claim 1, further comprising a display control unit that controls the display unit to superimpose the periodicity information together with at least one of an index representing pulsatility of blood flow, information regarding a stationary component of a change over time in the motion of the object, and information regarding Doppler velocity.

11. The ultrasound diagnostic apparatus according to claim 10 , wherein the display control unit controls the display unit to display the at least one information item using a first color bar and to display the periodicity information using a second color bar.

12. The target object is a region including an umbilical cord blood vessel, 2. The ultrasound diagnostic device according to claim 1, wherein the calculation unit calculates, for a region corresponding to a maternal blood vessel, information corresponding to a maternal heart rate as the periodicity information of the movement, and calculates, for a region corresponding to an umbilical blood vessel, information corresponding to a fetal heart rate as the periodicity information of the movement.

13. The target object is a region including an intrarenal interlobar vein, 2. The ultrasound diagnostic apparatus according to claim 1, wherein the calculation unit calculates periodicity information of the blood flow in the intrarenal interlobar vein, and generates information on a state of heart disease based on the calculated periodicity information of the blood flow in the intrarenal interlobar vein.

14. The analysis unit extracts a signal included in the signal data sequence for each direction of movement of the object, The ultrasound diagnostic apparatus according to claim 1 , wherein the calculation unit generates a spatial distribution of the periodicity information for each direction of motion of the object.

15. Transmitting ultrasonic waves into a subject and receiving echo signals corresponding to the ultrasonic waves; extracting information about a motion velocity of an object within the subject at each spatial point, the information being included in the signal data sequence obtained from the echo signals; Calculating periodicity information of the subject's motion based on the information; A method for ultrasound diagnosis, which generates a spatial distribution of the periodicity information.

16. an analysis unit that extracts information about a motion speed of an object inside the subject at each spatial point, the information being included in a signal data sequence obtained from an echo signal corresponding to an ultrasound wave transmitted into the subject; A calculation unit that calculates periodicity information of the subject's motion based on the information; and A generation unit that generates a spatial distribution of the periodicity information; An image processing device comprising:

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