JP2012110527A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

An object of the present invention is to guarantee the accuracy of diagnosis using motion information of blood vessel walls and blood flow.
An ultrasonic diagnostic apparatus according to an embodiment includes a transmission / reception unit 11, a tissue motion information acquisition unit 14a, a blood flow motion information acquisition unit 14b, and a control unit 17. The transmission / reception unit 11 performs ultrasonic transmission / reception of each scanning line once, causes the ultrasonic probe 1 to perform continuous scanning of a scanning range formed by a plurality of scanning lines, and continuously generates a reflected wave signal for one frame. To do. The tissue motion information acquisition unit 14a acquires the tissue velocity as tissue motion information by performing an autocorrelation operation on the reflected wave signals at the same place between adjacent frames. The blood flow information acquisition unit 14b performs IIR filter processing on the reflected wave signal at the same place in the reflected wave signal for each successive frame used for acquiring the tissue movement information, thereby providing the power of the blood flow. A value is acquired as blood flow movement information. The control unit 17 displays tissue motion information and blood flow motion information.
[Selection] Figure 1

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus.

  Conventionally, "blood flow motion information" such as blood flow velocity in blood vessels (especially in the carotid artery) and "blood vessel motion information" such as blood vessel wall displacement and strain have been measured at the same time. It is known that it is important in diagnosing the above, and an ultrasonic diagnostic apparatus is used for such measurement. For example, in the diagnosis of arteriosclerosis, an index relating to the hardness of a blood vessel is calculated from the diameter of the blood vessel measured from a B-mode image of the blood vessel and the blood pressure measured by a sphygmomanometer.

  In the diagnosis of arteriosclerosis, blood flow motion information is measured by a color Doppler method, and blood vessel motion information is also measured by a tissue Doppler method (TDI: Tissue Doppler Imaging). Here, in order to measure the blood flow velocity in the blood vessel using the color Doppler method, it is necessary to make the ultrasonic beam incident obliquely on the blood vessel. This is because the velocity obtained by the color Doppler method is an average velocity, and if the ultrasonic beam is perpendicular to the blood vessel, the average velocity becomes “0” and the blood flow velocity cannot be measured. For this reason, the color Doppler ultrasonic beam is transmitted so as to have an angle of about 10 to 20 degrees with respect to the blood vessel.

  On the other hand, in order to measure the motion information of the blood vessel wall, the blood vessel wall is displaced in a direction perpendicular to the traveling direction of the blood vessel, so it is better to apply an ultrasonic beam perpendicular to the blood vessel. For this reason, the ultrasonic beam for TDI is transmitted so as to have an angle of 90 degrees with respect to the blood vessel. In this way, in the diagnosis of arteriosclerosis, the color Doppler ultrasound beam and the TDI ultrasound beam are separately transmitted to measure blood flow motion information and blood vessel wall motion information, and An index relating to hardness is calculated. For example, in the diagnosis of arteriosclerosis, a color Doppler scan and a TDI scan are performed at an extremely high frame rate of 3500 fps (frame per second) in order to measure blood flow motion information and blood vessel wall motion information. Scanning is done.

JP 2004-41382 A

Hideyuki Hasegawa, Hiroshi Kanai, "Simultaneous Imaging of Artery-Wall Strain and Blood Flow by High Frame Rate Acquisition of RF Signals", IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol.55, No.12, December 2008

  By the way, the above-described conventional techniques need to perform separate ultrasonic scans in order to measure blood flow motion information and blood vessel wall motion information. Information could not be measured at the same time. In other words, in the conventional technique described above, scanning is performed at an extremely high frame rate in order to minimize the measurement deviation. However, the data that is the measurement source of each piece of motion information is the data collected at the same time. Absent. For this reason, the accuracy of diagnosis using blood vessel wall motion information and blood flow motion information acquired by a conventional scanning method is not necessarily guaranteed.

  The ultrasonic diagnostic apparatus according to the embodiment includes a transmission / reception unit, a tissue motion information acquisition unit, a blood flow motion information acquisition unit, and a display control unit. The transmission / reception unit performs one-time ultrasonic transmission / reception on each scanning line, and then causes the ultrasonic probe to perform continuous scanning of a scanning range formed by a plurality of scanning lines, thereby generating a reflected wave signal for one frame. Generate continuously. The tissue motion information acquisition unit is calculated by performing an autocorrelation operation on the reflected wave signals at the same place between adjacent frames among the reflected wave signals for each successive frame generated by the transmitting / receiving unit. The speed of the tissue is acquired as tissue motion information. The blood flow motion information acquisition unit is an infinite impulse response type filter for the reflected wave signal at the same place in the reflected wave signal for each successive frame used by the tissue motion information acquisition unit to acquire the tissue motion information. The power value of the blood flow estimated by performing the process is acquired as blood flow motion information. The display control unit controls the tissue movement information acquired by the tissue movement information acquisition unit and the blood flow movement information acquired by the blood flow movement information acquisition unit to be displayed on a predetermined display unit.

FIG. 1 is a diagram for explaining the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram for explaining a conventional scanning method performed for acquiring tissue motion information and blood flow motion information. FIG. 3 is a diagram (1) for explaining the scanning method according to the first embodiment. FIG. 4 is a diagram (2) for explaining the scanning method according to the first embodiment. FIG. 5 is a diagram for explaining processing of the B-mode processing unit and the image generation unit. FIG. 6 is a diagram for explaining the tissue motion information acquisition unit according to the first embodiment. FIG. 7 is a diagram (1) for explaining the blood flow motion information acquisition unit according to the first embodiment. FIG. 8 is a diagram (2) for explaining the blood flow motion information acquisition unit according to the first embodiment. FIG. 9 is a diagram for explaining a specific example of a display form of tissue motion information and blood flow motion information according to the first embodiment. FIG. 10 is a diagram for explaining the slow motion display executed by the control unit according to the first embodiment. FIG. 11 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 12 is a diagram for explaining the tissue motion information acquisition unit according to the second embodiment. FIG. 13 is a diagram for explaining a specific example of a display form of tissue exercise information according to the second embodiment. FIG. 14 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 15 is a diagram for explaining a configuration of an ultrasonic diagnostic apparatus according to the third embodiment. FIG. 16 is a diagram for explaining the speed calculation unit. FIG. 17 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the third embodiment.

  Hereinafter, embodiments of an ultrasonic diagnostic apparatus will be described in detail with reference to the accompanying drawings.

(First embodiment)
First, the configuration of the ultrasonic diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a diagram for explaining the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus according to the present embodiment includes an ultrasonic probe 1, a monitor 2, an input device 3, and an apparatus main body 10.

  The ultrasonic probe 1 includes a plurality of piezoelectric vibrators, and the plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission / reception unit 11 included in the apparatus main body 10 described later. The ultrasonic probe 1 receives a reflected wave from the subject P and converts it into an electrical signal. The ultrasonic probe 1 includes a matching layer and an acoustic lens provided in the piezoelectric vibrator, a backing material that prevents propagation of ultrasonic waves from the piezoelectric vibrator to the rear, and the like. The ultrasonic probe 1 is detachably connected to the apparatus main body 10.

  When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are reflected one after another at the discontinuous surface of the acoustic impedance in the body tissue of the subject P, and the ultrasonic probe is used as a reflected wave signal. 1 is received by a plurality of piezoelectric vibrators. The amplitude of the received reflected wave signal depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. Note that the reflected wave signal when the transmitted ultrasonic pulse is reflected on the moving blood flow or the surface of the heart wall depends on the velocity component of the moving body in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift (Doppler shift).

  Here, the present embodiment is applicable regardless of whether the ultrasonic scanning mode by the ultrasonic probe 1 is linear scanning or sector scanning. Below, the case where linear scanning is performed by the ultrasonic probe 1 which concerns on this embodiment is demonstrated.

  Further, in this embodiment, even when the subject P is scanned two-dimensionally by the ultrasonic probe 1 that is a one-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are arranged in a row, the one-dimensional ultrasonic wave is used. An object P is obtained by an ultrasonic probe 1 that mechanically swings a plurality of piezoelectric vibrators of the probe or an ultrasonic probe 1 that is a two-dimensional ultrasonic probe in which a plurality of piezoelectric vibrators are arranged in a two-dimensional grid. Even when scanning in three dimensions, it is applicable.

  The input device 3 includes a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, and the like, accepts various setting requests from an operator of the ultrasonic diagnostic apparatus, and accepts them to the apparatus body 10. Transfer various setting requests.

  The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus to input various setting requests using the input device 3, or displays an ultrasonic image generated in the apparatus main body 10. To do.

  The apparatus main body 10 is an apparatus that generates an ultrasonic image based on the reflected wave received by the ultrasonic probe 1. As shown in FIG. 1, the apparatus body 10 includes a transmission / reception unit 11, a frame buffer 12, a B-mode processing unit 13, a Doppler processing unit 14, an image processing unit 15, an image memory 16, and a control unit 17. And an internal storage unit 18.

  The transmission / reception unit 11 includes a trigger generation circuit, a transmission delay circuit, a pulsar circuit, and the like, and supplies a drive signal to the ultrasonic probe 1. The pulsar circuit repeatedly generates a rate pulse for forming a predetermined repetition frequency (PRF) transmission ultrasonic wave. The PRF is also called a rate frequency. Each transmission delay circuit generates a transmission delay time for each piezoelectric vibrator necessary for determining transmission directivity by focusing ultrasonic waves generated from the ultrasonic probe 1 into a beam shape. Give to rate pulse. The trigger generation circuit applies a drive signal (drive pulse) to the ultrasonic probe 1 at a timing based on the rate pulse. That is, the transmission delay circuit arbitrarily adjusts the transmission direction from the piezoelectric vibrator surface by changing the transmission delay time given to each rate pulse.

  The transmission / reception unit 11 has a function capable of instantaneously changing the transmission frequency, the transmission drive voltage, and the like in order to execute a predetermined scan sequence based on an instruction from the control unit 17 described later. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching its value or a mechanism for electrically switching a plurality of power supply units.

  The transmission / reception unit 11 includes an amplifier circuit, an A / D converter, a reception delay circuit, an adder, a quadrature detection circuit, and the like. The transmission / reception unit 11 performs various processing on the reflected wave signal received by the ultrasonic probe 1 and reflects it. Generate wave data. The amplifier circuit amplifies the reflected wave signal for each channel and performs gain correction processing. The A / D converter A / D converts the reflected wave signal whose gain is corrected. The reception delay circuit gives a reception delay time necessary for determining the reception directivity to the digital data. The adder performs addition processing of the reflected wave signal given the reception delay time by the reception delay circuit. By the addition processing of the adder, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is emphasized. Then, the quadrature detection circuit converts the output signal of the adder into a baseband in-phase signal (I signal, I: In-pahse) and a quadrature signal (Q signal, Q: Quadrature-phase). Then, the quadrature detection circuit stores the I signal and the Q signal (hereinafter referred to as I / Q signal) in the subsequent frame buffer 12 as reflected wave data.

  Here, the transmission / reception unit 11 according to the first embodiment can generate reflected wave data of a plurality of reception focus from the reflected wave signal of each piezoelectric vibrator obtained by one transmission of the ultrasonic beam. That is, the transmission / reception unit 11 according to the first embodiment is a circuit capable of performing parallel simultaneous reception processing.

  The ultrasound scanning method executed by the transceiver 11 according to the first embodiment using the ultrasound probe 1 will be described in detail later.

  The frame buffer 12 is a buffer that temporarily stores the reflected wave data (I / Q signal) generated by the transmission / reception unit 11. Specifically, the frame buffer 12 stores I / Q signals for several frames. For example, the frame buffer 12 is a first-in / first-out (FIFO) memory, stores an I / Q signal for a predetermined frame, and a new I / Q signal for one frame is generated by the transmission / reception unit 11. If it is, the I / Q signal for one frame with the oldest generation time is discarded, and the newly generated I / Q signal for one frame is stored.

  The I / Q signal for one frame is reflected wave data for generating one ultrasonic image, and the transmission / reception unit 11 performs scanning formed by a plurality of scanning lines (scan lines). By causing the ultrasonic probe 1 to perform ultrasonic transmission / reception within the range, an I / Q signal for one frame is generated.

  The B mode processing unit 13 reads the reflected wave data (I / Q signal) generated by the transmission / reception unit 11 from the frame buffer 12, and performs logarithmic amplification, envelope detection processing, logarithmic compression, etc. on the read reflected wave data. As a result, data (B mode data) in which the signal intensity is expressed by brightness is generated.

  The Doppler processing unit 14 reads the reflected wave data (I / Q signal) generated by the transmission / reception unit 11 from the frame buffer 12 and performs frequency analysis on the read reflected wave data, so that the Doppler effect of the moving object within the scanning range is obtained. The data (Doppler data) extracted from the exercise information based on is generated. Specifically, the Doppler processing unit 14 generates Doppler data obtained by extracting an average speed, a variance value, a power value, and the like over multiple points as motion information of the moving body.

  More specifically, the Doppler processing unit 14 is a processing unit capable of executing the tissue Doppler method and the color Doppler method, and as illustrated in FIG. 1, the tissue motion information acquisition unit 14a and the blood flow motion information acquisition unit 14b. And have. The tissue motion information acquisition unit 14a is a processing unit that acquires tissue motion information (tissue motion information) within a scanning range and generates tissue Doppler data for generating a tissue Doppler image indicating the tissue dynamics. . Further, the blood flow movement information acquisition unit 14b acquires movement information (blood flow movement information) of blood flow within the scanning range, and generates color Doppler data indicating the dynamics of blood flow. Is a processing unit for generating

  The tissue movement information acquisition process of the tissue movement information acquisition unit 14a according to the first embodiment and the blood flow movement information acquisition process of the blood flow movement information acquisition unit 14b according to the first embodiment will be described in detail later. Describe.

  The image processing unit 15 generates a display ultrasonic image using the data generated by the B-mode processing unit 13 and the Doppler processing unit 14, and performs image processing on the generated ultrasonic image. It is. The image processing unit 15 illustrated in FIG. 1 includes an image generation unit 15a and an image composition unit 15b. The image generation unit 15a generates an ultrasonic image from the data generated by the B mode processing unit 13 and the Doppler processing unit 14. That is, the image generation unit 15a generates a B-mode image in which the intensity of the reflected wave is expressed by luminance from the B-mode data generated by the B-mode processing unit 13.

  In addition, the image generation unit 15a is an average velocity image, a dispersion image, a power image, or a combination image representing moving body information (blood flow movement information or tissue movement information) from the Doppler data generated by the Doppler processing unit 14. Generate a Doppler image of Specifically, the image generation unit 15a generates a tissue Doppler image using the tissue Doppler data generated from the tissue motion information, and generates a color Doppler image from the color Doppler data generated from the blood flow motion information.

  Here, the image generation unit 15a generally converts (scan converts) a scanning line signal sequence of ultrasonic scanning into a scanning line signal sequence of a video format typified by a television or the like, and serves as a display image. Generate an ultrasound image. Specifically, the image generation unit 15a generates an ultrasonic image as a display image by performing coordinate conversion in accordance with the ultrasonic scanning mode by the ultrasonic probe 1. In addition to the scan conversion, the image generation unit 15a performs various image processing, such as image processing (smoothing processing) for regenerating an average luminance image using a plurality of image frames after scan conversion, Image processing (edge enhancement processing) using a differential filter is performed in the image.

  The tissue Doppler image and the color Doppler image generated by the image generation unit 15a according to the first embodiment will be described in detail later.

  The image composition unit 15b generates a composite image in which character information, scales, body marks, and the like of various parameters are combined with various ultrasonic images generated by the image generation unit 15a. Further, the image composition unit 15b generates a composite image in which various ultrasonic images generated by the image generation unit 15a are superimposed, or generates an image for displaying in parallel the various ultrasonic images generated by the image generation unit 15a. Or

  The synthesized image generated by the image synthesizing unit 15b according to the first embodiment will be described in detail later.

  The image memory 16 is a memory that stores the ultrasonic image generated by the image generation unit 15a and the combined image generated by the image combining unit 15b. The image memory 16 can also store data (raw data) generated by the B-mode processing unit 13 and the Doppler processing unit 14.

  The internal storage unit 18 stores various data such as a control program for performing ultrasonic transmission / reception, image processing and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), diagnostic protocol, and various body marks. To do. The internal storage unit 18 is also used for storing images stored in the image memory 16 as necessary. The data stored in the internal storage unit 18 can be transferred to an external peripheral device via an interface (not shown).

  The control unit 17 controls the entire processing of the ultrasonic diagnostic apparatus. Specifically, the control unit 17 is based on various setting requests input from the operator via the input device 3 and various control programs and various data read from the internal storage unit 18. The processing of the processing unit 13, the Doppler processing unit 14, and the image processing unit 15 is controlled. The control unit 17 also controls the monitor 2 to display an ultrasonic image and a composite image stored in the image memory 16 and a GUI for the operator to specify various processes.

  The overall configuration of the ultrasonic diagnostic apparatus according to the first embodiment has been described above. With this configuration, the ultrasonic diagnostic apparatus according to the first embodiment acquires tissue motion information and blood flow motion information by performing an ultrasound scan in a scanning range including blood vessels, for example, the carotid artery. The ultrasonic diagnostic apparatus according to the first embodiment presents tissue motion information and blood flow motion information to a doctor who diagnoses arteriosclerosis. Specifically, the ultrasonic diagnostic apparatus according to the first embodiment displays various images generated based on tissue motion information and blood flow motion information. Note that the tissue motion information acquired in the present embodiment is blood vessel wall motion information.

  That is, the ultrasonic diagnostic apparatus according to the first embodiment acquires blood flow motion information by a color Doppler method, and acquires tissue (blood vessel wall) motion information by a tissue Doppler method. Here, the conventional ultrasound diagnostic apparatus separately performs an ultrasound scan for acquiring tissue (blood vessel wall) motion information and an ultrasound scan for acquiring blood flow motion information. FIG. 2 is a diagram for explaining a conventional scanning method performed for acquiring tissue motion information and blood flow motion information.

  In order to acquire the blood vessel wall motion information, it is better to apply an ultrasonic beam perpendicular to the blood vessel because the blood vessel wall is displaced in a direction perpendicular to the traveling direction of the blood vessel. For this reason, the ultrasonic beam transmitted from the ultrasonic probe 1 in the tissue Doppler method is transmitted so as to have an angle of 90 degrees with respect to the blood vessel, as shown in FIG.

  On the other hand, in order to acquire blood flow movement information, it is necessary to make an ultrasonic beam incident on the blood vessel obliquely. This is because the velocity obtained by the color Doppler method is an average velocity, and if the ultrasonic beam is perpendicular to the blood vessel, the average velocity becomes “0” and the blood flow velocity cannot be measured. For this reason, conventionally, an ultrasonic beam transmitted from the ultrasonic probe 1 for color Doppler is transmitted obliquely, for example, 70 degrees or 110 degrees as shown in FIG. In FIG. 2C, the blood vessel wall located at a position close to the ultrasonic probe 1 is shown as an upper blood vessel wall, and the blood vessel wall located at a position far from the ultrasonic probe 1 is shown as a lower blood vessel wall.

  That is, in the conventional scanning method, as shown in FIG. 2C, the dynamics of the upper blood vessel wall and the lower blood vessel wall, and the dynamics of blood (blood flow) flowing between the upper blood vessel wall and the lower blood vessel wall Therefore, it is necessary to separately perform the blood vessel wall observation scan A and the blood flow observation scan B. For this reason, blood vessel wall motion information and blood flow motion information are acquired from reflected wave data generated by scans performed at different times.

  Further, in order to minimize the observation deviation between the blood vessel wall motion information and the blood flow motion information, for example, the blood vessel wall observation scan A and the blood flow observation scan B are each performed at an extremely high speed of 3500 fps (frame per second). Even when scanning is performed at different frame rates, the reflected wave data from which the blood vessel wall motion information and blood flow motion information are obtained are different. For this reason, the accuracy of diagnosis using the blood vessel wall motion information and blood flow motion information acquired by the conventional scanning method is not necessarily guaranteed because it is not based on the data acquired at the same time.

  Therefore, the ultrasonic diagnostic apparatus according to the first embodiment acquires blood flow motion information and blood vessel wall motion information using the same reflected wave data generated at the same time. 3 and 4 are diagrams for explaining the scanning method according to the first embodiment.

  As shown in FIG. 3A, the ultrasonic probe 1 according to the first embodiment is applied to a blood vessel in the same manner as a normal B-mode scan or a conventional blood vessel wall observation scan A. Transmit an ultrasonic beam vertically. That is, as shown in FIG. 3B, the ultrasonic probe 1 according to the first embodiment performs B by scanning C that transmits an ultrasonic beam perpendicular to the upper blood vessel wall and the lower blood vessel wall. A color Doppler scan is performed together with a mode scan and a tissue Doppler scan.

  For this reason, the transmission / reception unit 11 according to the first embodiment performs the ultrasonic probe 1 to continuously scan the scanning range formed by a plurality of scanning lines after performing ultrasonic transmission / reception in each scanning line once. By doing so, a reflected wave signal (reflected wave data) for one frame is continuously generated.

  That is, as shown in FIG. 4, the transmission / reception unit 11 according to the first embodiment performs ultrasonic transmission / reception in each piezoelectric transducer of the ultrasonic probe 1 that performs linear scanning once, thereby performing one frame worth. Reflected wave data (I / Q signal) is continuously generated along a time series.

  In addition, the order of ultrasonic transmission / reception in a plurality of scanning lines can be changed to any order by the processing of the transmission / reception unit 11 based on the control of the control unit 17. Further, the scan range of the tissue Doppler scan and the color Doppler scan may be narrower than the scan range of the B-mode scan.

  Here, it is desirable that the frame rate of the ultrasonic scanning executed by the transmission / reception unit 11 is, for example, 1000 fps or more. The reason will be described later.

  FIG. 5 is a diagram for explaining processing of the B-mode processing unit and the image generation unit. The B-mode processing unit 13 generates B-mode data from the reflected wave signal (reflected wave data) for each successive frame generated by the transmission / reception unit 11. That is, the B-mode processing unit 13 reads an I / Q signal for one frame from the frame buffer 12, and sequentially performs logarithmic amplification, envelope detection, and logarithmic compression as shown in FIG. Generate data. Then, the image generation unit 15a sequentially generates B mode images from the sequentially generated B mode data. For example, as illustrated in FIG. 5B, the image generation unit 15 a performs the B mode image of the “n−2” frame, the B mode image of the “n−1” frame, and the B mode image of the “n” frame. Mode images are generated sequentially.

  Then, the tissue motion information acquisition unit 14a shown in FIG. 1 calculates the autocorrelation for the reflected wave signals at the same place between adjacent frames among the reflected wave signals for each successive frame generated by the transmitting / receiving unit 11. The velocity of the tissue (blood vessel wall) calculated by performing is acquired as tissue motion information. FIG. 6 is a diagram for explaining the tissue motion information acquisition unit according to the first embodiment.

  For example, the tissue motion information acquisition unit 14 a reads the I / Q signal of the “n” frame and the I / Q signal of the “n−1” frame from the frame buffer 12. Then, as shown in FIG. 6, the tissue motion information acquisition unit 14 a performs autocorrelation calculation between the “n” frame and the “n−1” frame at the same point, thereby Calculate the velocity of the tissue (blood vessel wall) in the frame.

  Hereinafter, the autocorrelation calculation performed by the tissue motion information acquisition unit 14a will be described using mathematical expressions. The I / Q signal at the point for speed calculation in the “n−1” th frame is “IQ (n−1)”, and the I / Q signal at the same location in the “n” th frame is “IQ (n)”. ”, The autocorrelation“ ac ”is calculated as a product of the complex conjugate of“ IQ (n−1) ”and“ IQ (n) ”as shown in the following equation (1).

  Then, the speed “v” of the point to be speed-calculated is calculated by the following equation (2) from the real part “Real (ac)” and the imaginary part “Image (ac)” of “ac”.

  Thereby, the tissue motion information acquisition unit 14a acquires a two-dimensional velocity vector of a point to be a velocity calculation target. The tissue motion information acquisition unit 14a acquires the blood vessel wall speed as tissue motion information by executing this process at multiple points using the I / Q signal of the “n” frame, and acquires the tissue of the “n” frame. Generate Doppler data. Then, the image generation unit 15a generates a tissue Doppler image of the “n” th frame.

  Then, the blood flow motion information acquisition unit 14b has an infinite impulse response to the reflected wave signal at the same place in the reflected wave signal for each successive frame used by the tissue motion information acquisition unit 14a to acquire the tissue motion information. A blood flow power value estimated by performing a type filter (IIR filter, IIR: Infinite Impulse Response) process is acquired as blood flow motion information. 7 and 8 are diagrams for explaining the blood flow movement information acquisition unit according to the first embodiment.

  As illustrated in FIG. 7, the blood flow motion information acquisition unit 14b acquires a power value using the output result of the IIR filter as a Wall filter that is a high-pass filter. The Wall filter used in the present embodiment is a second-order IIR filter represented by the following formula (3).

  Here, “x (n)” shown in Expression (3) is the latest I / Q signal of the “n” frame, and “x (n−1)” is the “n−1” frame. It is an I / Q signal, and “x (n−2)” is an I / Q signal of the “n−2” frame. In addition, “y (n)” shown in Expression (3) is a blood flow motion component included in the I / Q signal of the “n” th frame, and “y (n−1)” is “n” −1 ”frame I / Q signal included in the blood flow motion component, and“ y (n−2) ”represents the blood flow motion component included in the“ n−2 ”frame I / Q signal. It is. In addition, “b0”, “b1”, “b2”, “a1”, and “a2” shown in Expression (3) are “x (n)”, “x (n−1)”, “x (n)”, respectively. -2) "," y (n-1) "and" y (n-2) ". With these coefficients, the slow motion signal is removed, and the motion component of the blood flow at the point that is the acquisition target of the blood flow motion is calculated in the I / Q signal of the “n” frame by Equation (3).

  Here, in a normal color Doppler method, ultrasonic wave transmission / reception is performed a plurality of times for the same scanning line, and blood flow motion components are acquired from a plurality of I / Q signals on the same scanning line. That is, in the ordinary color Doppler method, an IIR filter is applied to a finite data string called a packet. However, in this embodiment, the ultrasonic wave transmission / reception is performed only once on one scanning line, and the IIR filter is applied to the reflected wave data of infinitely continuous frames. Thereby, in this embodiment, an ideal filter characteristic is obtained.

  As described above, the transmission / reception unit 11 according to the first embodiment transmits an ultrasonic beam along a scanning line perpendicular to the blood flow. The blood flow component becomes a cosine component of the angle between the ultrasonic beam and the blood flow, and therefore cannot be captured if the ultrasonic beam is completely orthogonal to the blood flow. However, the ultrasonic beam in each scanning line is not transmitted from one piezoelectric vibrator of the ultrasonic probe 1, but actually, in order to give transmission directivity, the left diagram in FIG. As shown in FIG. 4, the ultrasonic waves are formed by a plurality of ultrasonic waves transmitted from a channel including a predetermined number of piezoelectric vibrators. That is, in the ultrasonic beam transmitted from the channel having the aperture width, in addition to the ultrasonic beam along the scanning line, as shown in the left diagram of FIG. There is an incident ultrasonic beam.

  For this reason, the distribution of the frequency shift resulting from the dynamics of the blood flow obtained as the output of the IIR filter shown in Expression (3) is the average velocity “0” as shown in the right diagram of FIG. ”Is close to the normal distribution. For this reason, the average velocity of the blood flow calculated from the output of the IIR filter is substantially “0”.

  However, the integrated value (area) of the distribution is a blood flow power value as shown in FIG. Therefore, the blood flow motion information acquisition unit 14b according to the first embodiment estimates the power value by the following equation (4) without estimating the blood flow velocity.

  That is, the blood flow motion information acquisition unit 14b according to the first embodiment executes the processing of Expression (3) and Expression (4) over multiple points using the I / Q signal of the “n” frame. Thus, the power value of the blood flow in the “n” frame is acquired as blood flow motion information, and power data is generated as color Doppler data in the “n” frame. Then, the image generation unit 15a generates a power image as a color Doppler image of the “n” th frame.

  As described above, in the first embodiment, using the same reflected wave data group, B-mode data for generating a B-mode image in which a tissue form is depicted is generated, and tissue (blood vessel wall) motion is generated. Tissue velocity information as information and “blood flow power value” are acquired.

  The control unit 17 illustrated in FIG. 1 controls the monitor 2 to display the tissue motion information acquired by the tissue motion information acquisition unit 14a and the blood flow motion information acquired by the blood flow motion information acquisition unit 14b. .

  An example of a display form of tissue motion information and blood flow motion information performed by the control unit 17 will be described with reference to FIG. FIG. 9 is a diagram for explaining a specific example of a display form of tissue motion information and blood flow motion information according to the first embodiment.

  Specifically, under the control of the control unit 17, the image composition unit 15b generates a composite image obtained by combining the tissue Doppler image generated from the tissue motion information and the power image generated from the blood flow motion information. First, the control unit 17 extracts a high luminance area larger than a predetermined luminance value in the B mode image of the “n” frame shown in FIG. Such a high luminance region is a region corresponding to the upper blood vessel wall and the lower blood vessel wall.

  Then, the control unit 17 causes the image composition unit 15b to extract the region of the tissue Doppler image of the “n” frame corresponding to the high luminance region of the B mode image of the “n” frame. Further, the control unit 17 causes the image composition unit 15b to extract a region where the pixel value (power value) is equal to or greater than a predetermined threshold (TH) in the power image of the “n” frame. Then, under the control of the control unit 17, the image composition unit 15b generates a composite image of the “n” th frame by combining the extracted regions. As shown in FIG. 9, the composite image includes a tissue Doppler image of the upper blood vessel wall, a power image having a power value equal to or higher than a predetermined threshold (TH), and an image obtained by combining the tissue Doppler image of the lower blood vessel wall. Become. In the synthesized image shown in FIG. 9, the hue is depicted so as to differ depending on the speed and moving direction of the blood vessel wall, and the shade of gray is depicted depending on the magnitude of the power value. For example, in a composite image that is displayed sequentially along the time series, if the blood vessel wall is moving upward, the blood vessel wall moves downward with a hue based on red. If it is, the speed of the blood vessel wall is displayed in a hue based on blue. Further, in the composite image that is sequentially displayed along the time series, the aspect in which the fluctuation of the power value of the blood flow fluctuates depending on the shade of gray is depicted.

  Then, the control unit 17 displays the composite image of the “n” frame, the B mode image of the “n” frame, and the monitor 2 shown in FIG.

  Here, as described above, the frame rate of the ultrasonic scanning executed by the transmission / reception unit 11 is, for example, 1000 fps or more. This is because when the frame rate is slow with respect to the blood flow velocity, the speckle movement observed in the sequentially generated power images is folded. For this reason, the transmission / reception unit 11 according to the first embodiment uses one frame of ultrasonic waves at a frame rate at which the speckle movement between power images obtained by imaging the blood flow power value is in the same direction as the blood movement. The ultrasonic probe 1 is controlled so that transmission / reception is performed. In order to realize such a frame rate, the transmission / reception unit 11 performs the parallel simultaneous reception described above according to an instruction from the control unit 17.

  However, the frame rate that can be generally displayed on the monitor 2 included in the ultrasonic diagnostic apparatus is, for example, 60 fps, and B-mode images and composite images generated at a frame rate of 1000 fps cannot be displayed. Therefore, the control unit 17 according to the present embodiment controls the display interval of each image continuously generated from the tissue motion information and the blood flow motion information so as to be larger than the frame rate. In other words, the control unit 17 displays the B-mode image and the composite image in slow motion. An operator such as a doctor can simultaneously observe tissue motion information and blood flow motion information acquired from the same data by referring to the composite images sequentially displayed in time series.

  FIG. 10 is a diagram for explaining the slow motion display executed by the control unit according to the first embodiment. For example, as shown in FIG. 10, when a B-mode image or a composite image is generated at 1984 fps, the control unit 17 displays 66 times of slow motion display so that it is about 30 fps.

  Note that the slow motion display by the control unit 17 is performed by, for example, pressing a freeze button of the input device 3 and reading a group of B-mode images and composite images stored in the image memory 16 after the freeze. It is. That is, the slow motion display by the control unit 17 is performed as post-processing after image generation.

  Or the slow motion display by the control part 17 is performed in real time using the method currently disclosed by Unexamined-Japanese-Patent No. 2001-178723, for example. Specifically, when the slow motion display is performed in real time, the control unit 17 displays the composite image generated at the frame rate of the ultrasonic scanning at the frame rate that can be displayed on the monitor 2. Then, when the predetermined time elapses, the control unit 17 displays the synthesized image generated immediately after the predetermined time elapses, and sequentially displays new synthesized images in through motion in order from the synthesized image.

  The control unit 17 performs various display modes in addition to the display mode described above (parallel display of the B-mode image and the tissue Doppler image based on the luminance value of the B-mode image and the combined image of the power image). I can do it. For example, the control unit 17 can display a B-mode image, a tissue Doppler image, and a power image in parallel, or can display a composite image obtained by combining these three types of images. In addition, the control unit 17 can perform single display of the composite image of the tissue Doppler image and the power image, and parallel display of the tissue Doppler image and the power image. The control unit 17 also, for example, the average speed of the blood vessel wall in the region of interest designated in the blood vessel wall on the B-mode image by the operator and the interest designated in the blood vessel by the operator on the B-mode image. It is also possible to display the average power value of blood flow in the region.

  Next, processing of the ultrasonic diagnostic apparatus according to the first embodiment will be described with reference to FIG. FIG. 11 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. In the following, processing after the transmission / reception unit 11 starts ultrasonic transmission / reception at a frame rate of 1000 fps, for example, will be described.

  As shown in FIG. 11, the ultrasonic diagnostic apparatus according to the first embodiment determines whether or not data (I / Q signal) for one new frame is stored in the image memory 16 (step S101). . Here, when data for one new frame is not stored (No at Step S101), the ultrasonic diagnostic apparatus according to the first embodiment enters a standby state.

  On the other hand, when data for one new frame is stored (Yes in step S101), the B-mode processing unit 13 generates B-mode data, and the image generation unit 15a generates a B-mode image (step S102). . The tissue motion information acquisition unit 14a acquires the speed of the tissue (blood vessel wall) by performing the arithmetic processing of Expression (1) and Expression (2) on the new data for one frame, and the image The generation unit 15a generates a tissue Doppler image (Step S103). That is, the tissue motion information acquisition unit 14a generates tissue Doppler data by acquiring the velocity of the tissue by self-mutual calculation processing.

  Subsequently, the blood flow movement information acquisition unit 14b acquires the power value by performing arithmetic processing of Expression (3) and Expression (4) on the new data for one frame, and the image generation unit 15a Then, a power image is generated (step S104). That is, the blood flow movement information acquisition unit 14b performs IIR filter processing shown in Expression (3) on the data for one new frame, and further shows Expression (4) on the output of the IIR filter. By performing arithmetic processing, the power value of blood flow is estimated and power data is generated.

  Then, the image composition unit 15b generates a composite image of the tissue Doppler image generated in Step S103 and the power image generated in Step S104 based on the luminance value of the B-mode image generated in Step S102 ( Step S105).

  Thereafter, the control unit 17 determines whether or not a predetermined time set for slow motion display has elapsed (step S106). If the predetermined time has not elapsed (No at Step S106), the control unit 17 waits until the predetermined time elapses.

  On the other hand, when the predetermined time has elapsed (Yes at Step S106), the control unit 17 controls the monitor 2 to display the B mode image generated at Step S102 and the composite image generated at Step S105 in parallel ( Step S107) and the process is terminated. Then, the ultrasonic diagnostic apparatus according to the first embodiment further performs processing after step S102 when new reflected wave data for one frame is stored. Note that the order of processing by the B-mode processing unit 13, the tissue motion information acquisition unit 14a, and the blood flow motion information acquisition unit 14b is not limited to the order shown in FIG. 11, and may be executed in any order. I can do it. Moreover, the case where the process by the B mode process part 13, the tissue movement information acquisition part 14a, and the blood flow movement information acquisition part 14b is performed by a parallel process may be sufficient.

  As described above, in the first embodiment, the transmission / reception unit 11 performs one-time ultrasonic transmission / reception in each scanning line and then performs continuous scanning of a scanning range formed by a plurality of scanning lines with the ultrasonic probe. By executing the operation 1, the reflected wave signal for one frame is continuously generated. The tissue motion information acquisition unit 14a is calculated by performing an autocorrelation operation on the reflected wave signals at the same place between adjacent frames among the reflected wave signals for each successive frame generated by the transmission / reception unit 11. The speed of the tissue to be acquired is acquired as tissue motion information. The blood flow motion information acquisition unit 14b is an infinite impulse response filter for the reflected wave signal at the same place in the reflected wave signal for each successive frame used by the tissue motion information acquisition unit 14a to acquire the tissue motion information. The power value of the blood flow estimated by performing the process is acquired as blood flow motion information. The control unit 17 performs control so that the tissue motion information and the blood flow motion information are displayed on the monitor 2.

  That is, in the first embodiment, blood flow motion information and blood vessel wall motion information are acquired from the reflected wave signals at the same time (the same reflected wave signal), and thus are provided to a doctor who diagnoses arteriosclerosis. In conventional arteriosclerosis diagnosis data, there is no difference in acquisition time as in the prior art. Therefore, in the first embodiment, it is possible to guarantee the accuracy of diagnosis using the motion information of the blood vessel wall and blood flow.

  In the first embodiment, the transmission / reception unit 11 transmits / receives ultrasonic waves for one frame at a frame rate in which the speckle movement between the power images obtained by imaging the power value of the blood flow is in the same direction as the blood movement. The ultrasonic probe 1 is controlled so as to be performed.

  That is, in the first embodiment, it is possible to avoid the folding of the power value acquired as blood flow motion information. Therefore, in the first embodiment, it is possible to guarantee the accuracy of diagnosis using the power image.

  In the first embodiment, the control unit 17 controls the display interval of each image generated successively from the tissue motion information and the blood flow motion information so as to be larger than the frame rate. Therefore, in the first embodiment, it is possible to display in slow motion a composite image or a B-mode image generated at an ultra-high frame rate in accordance with the frame rate of the monitor 2 that is generally attached to the ultrasonic diagnostic apparatus. . Moreover, in 1st Embodiment, the visibility of a synthesized image and a B-mode image can be improved by displaying by slow motion.

(Second Embodiment)
In the second embodiment, a case will be described in which new tissue motion information is acquired using the tissue speed acquired in the first embodiment.

  The ultrasound diagnostic apparatus according to the second embodiment has the same configuration as the ultrasound diagnostic apparatus according to the first embodiment described with reference to FIG. 1, but the processing content of the tissue motion information acquisition unit 14a is the first. Different from the first embodiment. Hereinafter, the tissue motion information acquisition unit 14a according to the second embodiment will be described with reference to FIG. FIG. 12 is a diagram for explaining the tissue motion information acquisition unit according to the second embodiment.

  The tissue motion information acquisition unit 14a according to the second embodiment further acquires the tissue displacement calculated by integrating the tissue velocity in the time direction as tissue motion information. That is, as shown in FIG. 12A, the tissue motion information acquisition unit 14a is configured to store tissue at the same place between tissue Doppler data to be processed and tissue Doppler data generated immediately before the frame. The velocity of (blood vessel wall) is integrated in the time direction, that is, the frame direction. Thereby, the tissue motion information acquisition unit 14a acquires the displacement of the tissue (blood vessel wall). That is, the tissue motion information acquisition unit 14a calculates a displacement between the frames of the upper blood vessel wall and the lower blood vessel wall.

  The tissue motion information acquisition unit 14a according to the second embodiment further acquires tissue strain calculated by differentiating the tissue displacement in the spatial direction in the frame as tissue motion information. That is, as shown in FIG. 12B, the tissue motion information acquisition unit 14a calculates the displacement of the tissue (blood vessel wall) calculated over multiple points in the frame to be processed in the spatial direction (scan line direction). Differentiate into. Thereby, the tissue motion information acquisition unit 14a acquires the strain of the tissue (blood vessel wall). That is, the tissue motion information acquisition unit 14a calculates the strain of each of the upper blood vessel wall and the lower blood vessel wall.

  Then, the control unit 17 according to the second embodiment performs control so that the displacement of the tissue acquired by the tissue motion information acquisition unit 14a is displayed on the monitor 2. The control unit 17 according to the second embodiment controls the monitor 2 to display the tissue strain acquired by the tissue motion information acquisition unit 14a.

  The tissue displacement and tissue strain acquisition processing may be executed by the tissue motion information acquisition unit 14a or may be executed by the image processing unit 15. In the second embodiment, the tissue motion information acquisition unit 14a may acquire only the tissue displacement. In the second embodiment, the tissue motion information acquisition unit 14a acquires the tissue displacement and the tissue strain, and the control unit 17 performs both the tissue displacement and the tissue strain, or the tissue displacement and the tissue strain. Any one of the strains may be displayed. In the second embodiment, the control unit 17 may display at least one of tissue displacement and tissue strain together with the tissue velocity. Such setting is performed by an operator, for example.

  For example, the control unit 17 further displays the result of the additional process performed by the tissue exercise information acquisition unit 14a in the display form illustrated in FIG. FIG. 13 is a diagram for explaining a specific example of a display form of tissue exercise information according to the second embodiment.

  First, the control unit 17 receives a region of interest for displaying local tissue motion information from the operator. For example, the operator uses the mouse of the input device 3 to display a region of interest for displaying tissue motion information on each of the upper blood vessel wall and the lower blood vessel wall in the B-mode image or the composite image described in the first embodiment. To set. Accordingly, the control unit 17 sets a rectangular region of interest on each of the upper blood vessel wall and the lower blood vessel wall as shown in the left diagram of FIG.

  Further, the operator sets which tissue motion information is displayed from the tissue speed, the tissue displacement, and the tissue strain. That is, the operator selects at least one of tissue velocity, tissue displacement, and tissue strain. For example, the operator sets to display the tissue speed and the tissue displacement in the two set regions of interest. When such setting is performed, the control of the control unit 17 causes the tissue motion information acquisition unit 14a to calculate an average velocity obtained by averaging the tissue velocities at each point acquired in the region of interest. Further, under the control of the control unit 17, the tissue motion information acquisition unit 14a calculates an average displacement obtained by averaging the displacements of the tissue at each point acquired in the region of interest.

  Then, under the control of the control unit 17, the image synthesis unit 15b synthesizes arrows for displaying the average speed and the average displacement as vectors in each region of interest of the synthesized image, as shown in the left diagram of FIG. The monitor 2 displays the image shown in the left figure of FIG. In the left diagram of FIG. 13, the average speed is displayed as a vector with a solid arrow, and the average displacement is displayed as a vector with a dotted arrow.

  Further, the local tissue motion information may be displayed not only by the vector display shown in the left diagram of FIG. 13 but also by a graph display as shown in the right diagram of FIG. In the example shown in the left diagram of FIG. 13, a graph in which the average velocity in the region of interest set in the upper blood vessel wall is plotted along the time axis, and the average velocity in the region of interest set in the lower blood vessel wall. Is superimposed on the graph plotted along the time axis. Further, in the example shown in the left diagram of FIG. 13, a graph in which the average displacement in the region of interest set in the upper blood vessel wall is plotted along the time axis, and the region in the region of interest set in the lower blood vessel wall. A graph in which the average displacement is plotted along the time axis is superimposed and displayed. Further, in the example shown in the left diagram of FIG. 13, a value obtained by subtracting the average displacement in the region of interest set in the lower blood vessel wall from the average displacement in the region of interest set in the upper blood vessel wall is along the time axis. The plotted graph is superimposed. The graph shown in the left diagram of FIG. 13 is generated by the tissue motion information acquisition unit 14a or the image processing unit 15.

  Note that the size of the region of interest and the number of regions of interest to be set can be arbitrarily set by the operator. In addition, as described above, the display mode of various tissue exercise information may be a case where both vector display and graph display are performed, or a case where either vector display or graph display is performed. In addition, the various forms of tissue exercise information may be displayed by displaying numerical values.

  Next, processing of the ultrasonic diagnostic apparatus according to the second embodiment will be described with reference to FIG. FIG. 14 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the second embodiment. In the following, similarly to FIG. 11, processing after the transmission / reception unit 11 starts ultrasonic transmission / reception at a frame rate of 1000 fps, for example, will be described. In the following, a case where a tissue displacement acquisition request is input from the operator as new tissue motion information based on the tissue velocity will be described.

  As shown in FIG. 14, the ultrasonic diagnostic apparatus according to the second embodiment determines whether or not new data (I / Q signal) for one frame is stored in the image memory 16 (step S201). . Here, when data for one new frame is not stored (No in step S201), the ultrasonic diagnostic apparatus according to the second embodiment enters a standby state.

  On the other hand, when data for one new frame is stored (Yes at Step S201), the B-mode processing unit 13 generates B-mode data, and the image generation unit 15a generates a B-mode image (Step S202). . The tissue motion information acquisition unit 14a acquires the speed of the tissue (blood vessel wall) by performing the arithmetic processing of Expression (1) and Expression (2) on the new data for one frame, and the image The generation unit 15a generates a tissue Doppler image (Step S203).

  Subsequently, the blood flow movement information acquisition unit 14b acquires the power value by performing arithmetic processing of Expression (3) and Expression (4) on the new data for one frame, and the image generation unit 15a Then, a power image is generated (step S204).

  Further, the tissue motion information acquisition unit 14a acquires the tissue displacement by integrating the tissue velocity in the time direction as new tissue motion information (step S205). Then, the image composition unit 15b generates a composite image of the tissue Doppler image generated in Step S203 and the power image generated in Step S204 based on the luminance value of the B-mode image generated in Step S202 ( Step S206).

  Thereafter, the control unit 17 determines whether or not a predetermined time set for slow motion display has elapsed (step S207). If the predetermined time has not elapsed (No at Step S207), the control unit 17 waits until the predetermined time elapses.

  On the other hand, when the predetermined time has elapsed (Yes at Step S207), the control unit 17 controls the monitor 2 to acquire the B-mode image generated at Step S202, the synthesized image generated at Step S206, and the Step S205. The displacement is displayed in parallel (step S208), and the process is terminated. For example, the control unit 17 displays the displacement (average displacement in the region of interest) acquired in step S205 as a vector and a graph. Then, the ultrasonic diagnostic apparatus according to the second embodiment further performs the processing after step S202 when new reflected wave data for one frame is stored. Note that the order of processing by the B-mode processing unit 13, the tissue motion information acquisition unit 14a, and the blood flow motion information acquisition unit 14b is not limited to the order shown in FIG. 14, and may be executed in any order. I can do it. Moreover, the case where the process by the B mode process part 13, the tissue movement information acquisition part 14a, and the blood flow movement information acquisition part 14b is performed by a parallel process may be sufficient.

  As described above, in the second embodiment, the tissue motion information acquisition unit 14a further acquires the tissue displacement calculated by integrating the tissue velocity in the time direction as tissue motion information. The control unit 17 performs control so that the displacement of the tissue is displayed on the monitor 2.

  Therefore, in the second embodiment, it is possible to clearly provide the doctor with the degree of expansion / contraction repeated on the blood vessel wall.

  In the second embodiment, the tissue motion information acquisition unit 14a further acquires the tissue strain calculated by differentiating the tissue displacement in the spatial direction in the frame as tissue motion information. The control unit 17 performs control so that the strain of the tissue is displayed on the monitor 2.

  Therefore, in the second embodiment, the degree of flexibility of the blood vessel wall can be clearly provided to the doctor.

(Third embodiment)
In the third embodiment, a case will be described in which the blood flow velocity is calculated using the blood flow power value acquired in the first embodiment, and further, an index related to the blood vessel properties is calculated.

  First, the configuration of an ultrasonic diagnostic apparatus according to the third embodiment will be described. FIG. 15 is a diagram for explaining a configuration of an ultrasonic diagnostic apparatus according to the third embodiment. As shown in FIG. 15, the ultrasonic diagnostic apparatus according to the third embodiment has a speed within the image processing unit 15 as compared with the ultrasonic diagnostic apparatus according to the first embodiment described with reference to FIG. 1. The difference is that it further includes a calculator 15c and an index calculator 15d. Hereinafter, these will be mainly described.

  The speed calculation unit 15c illustrated in FIG. 15 calculates the motion vector of each tracking point by tracking speckles between successive power images in the power image obtained by imaging the power value of the blood flow. The motion vector of each tracking point is calculated as the blood flow velocity.

  Here, for example, when the power image described in the first embodiment is observed at an ultra-high frame rate of 1000 fps or higher, it is possible to grasp the aspect of blood movement due to speckle movement. That is, a two-dimensional motion vector of speckle motion can be calculated by performing a cross-correlation operation between successive power images. FIG. 16 is a diagram for explaining the speed calculation unit.

  For example, the speed calculation unit 15c sets a plurality of tracking points in the display area of the power image in the composite image (the intravascular region sandwiched between the high-luminance regions of the B-mode image) as illustrated in FIG. To do. The interval and number of tracking points can be arbitrarily set.

  Then, the velocity calculation unit 15c performs tracking point tracking between the power image to be processed and the power image generated immediately before the power image, thereby obtaining the two-dimensional motion vector of each tracking point. calculate. Then, the speed calculation unit 15c calculates the calculated two-dimensional motion vector as a blood two-dimensional motion vector (blood flow speed).

  Then, the control unit 17 according to the third embodiment performs control to display the blood flow velocity calculated by the velocity calculation unit 15c on the monitor 2 as blood flow motion information. For example, the control unit 17 according to the third embodiment controls the image synthesizing unit 15b so that the two-dimensional blood is displayed on the power image that is the target of the synthesized image, as illustrated in FIG. An arrow corresponding to the motion vector is further superimposed. The direction of each arrow shown in (B) of FIG. 16 reflects the direction of the two-dimensional motion vector calculated at each tracking point. The length of each arrow shown in (B) of FIG. This reflects the scalar quantity of the two-dimensional motion vector calculated at the tracking point.

  Furthermore, the control unit 17 may superimpose the scalar a histogram of the motion vector of each tracking point by controlling the image composition unit 15b as shown in FIG. Moreover, the control part 17 may superimpose the average speed b of each tracking point, as shown to (B) of FIG. 16, by controlling the image synthetic | combination part 15b. In the example shown in FIG. 16B, it is indicated that the average speed b is “332 mm / s”.

  And the control part 17 controls the image synthetic | combination part 15b, and further superimposes the synthetic | combination image shown to (B) of FIG. It should be noted that the blood flow velocity calculated by the velocity calculation unit 15c is selected from each display form even when presented as a vector display, a histogram display, and a numerical display as shown in FIG. It may be displayed in one or a plurality of selected display forms. Further, the control unit 17 may cause the image generation unit 15a to generate an image corresponding to a normal color Doppler image in which the blood flow velocity is displayed in color using the blood flow velocity calculated by the velocity calculation unit 15c. good.

  As described above, in the third embodiment, the blood flow velocity can be obtained from the same reflected wave signal together with the blood vessel wall velocity, the blood vessel wall displacement, the blood vessel wall distortion, and the blood flow power value. . Based on these pieces of information, it is possible to calculate an index (parameter) indicating the properties of the blood vessel.

  Therefore, the index calculation unit 15d illustrated in FIG. 15 is based on at least one of the tissue motion information acquired by the tissue motion information acquisition unit 14a and the blood flow motion information acquired by the blood flow motion information acquisition unit 14b. An index related to the properties of For example, the index calculation unit 15d includes a “blood vessel wall speed” that is tissue motion information, a “blood flow speed” that is calculated based on a power image that is generated from a power value that is blood flow motion information, and the following: The index is calculated using Equation (5). In the following equation (5), “V (x)” is the blood flow velocity at the position “x” in the direction parallel to the blood vessel, and “V (x + Δx)” is the position “x + Δx” in the direction parallel to the blood vessel. The blood flow velocity in "." In the following formula (5), “U” is the velocity of the blood vessel wall at the position “x”.

  The numerator of the formula (5) is a pressure difference by a simple Bernoulli formula, and the denominator of the formula (5) is a change in the blood vessel diameter. The index calculation unit 15d executes the index calculation process using Expression (5), for example, at a minute time interval over one heartbeat. A plurality of indexes calculated at minute time intervals by such processing can be used as values indicating the hardness of the blood vessel.

  Then, the control unit 17 according to the third embodiment performs control so that the index calculated by the index calculation unit 15d is displayed on the monitor 2.

  The data used for the index calculation of the index calculation unit 15d is not limited to the blood vessel wall speed and the blood flow speed. The data used for the index calculation of the index calculation unit 15d may be at least one data of the blood vessel wall speed, the blood vessel wall displacement, the blood vessel wall distortion, the blood flow power value, and the blood flow speed. Further, the index calculation unit 15d uses at least one of the blood vessel wall velocity, the blood vessel wall displacement, the blood vessel wall distortion, the blood flow power value, and the blood flow velocity, and the blood vessel diameter measured from the B-mode image. An index may be calculated. In any case, the index calculation unit 15d can calculate an index related to the properties of the blood vessel using various data obtained simultaneously with the reflected wave data generated at the same time.

  Next, processing of the ultrasonic diagnostic apparatus according to the third embodiment will be described with reference to FIG. FIG. 17 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the third embodiment. In the following, similarly to FIG. 11 and FIG. 14, processing after the transmission / reception unit 11 starts ultrasonic transmission / reception at a frame rate of 1000 fps, for example, will be described. In the following, similarly to FIG. 14, a case where a tissue displacement acquisition request is input from the operator as new tissue motion information based on the tissue velocity will be described.

  As shown in FIG. 17, the ultrasonic diagnostic apparatus according to the third embodiment determines whether or not data (I / Q signal) for one new frame has been stored in the image memory 16 (step S301). . Here, when data for one new frame is not stored (No in step S301), the ultrasonic diagnostic apparatus according to the third embodiment is in a standby state.

  On the other hand, when data for one new frame is stored (Yes in step S301), the B-mode processing unit 13 generates B-mode data, and the image generation unit 15a generates a B-mode image (step S302). . The tissue motion information acquisition unit 14a acquires the speed of the tissue (blood vessel wall) by performing the arithmetic processing of Expression (1) and Expression (2) on the new data for one frame, and the image The generation unit 15a generates a tissue Doppler image (Step S303).

  Subsequently, the blood flow movement information acquisition unit 14b acquires the power value by performing arithmetic processing of Expression (3) and Expression (4) on the new data for one frame, and the image generation unit 15a Then, a power image is generated (step S304).

  Further, the tissue motion information acquisition unit 14a acquires tissue displacement by integrating the tissue velocity in the time direction as new tissue motion information (step S305). Then, the velocity calculation unit 15c calculates a blood flow velocity vector by performing speckle tracking between power images (step S306).

  Thereafter, the image composition unit 15b generates a composite image of the tissue Doppler image generated in step S303, the power image generated in step 304, and the blood flow velocity vector calculated in step S306 (step S307). Furthermore, the index calculation unit 15d calculates an index related to the properties of the blood vessel using, for example, the blood vessel wall speed, the blood flow speed, and Expression (5) (step S308).

  Thereafter, the control unit 17 determines whether or not a predetermined time set for slow motion display has elapsed (step S309). If the predetermined time has not elapsed (No at Step S309), the control unit 17 waits until the predetermined time elapses.

  On the other hand, when the predetermined time has elapsed (Yes at step S309), the control unit 17 controls the monitor 2 to acquire the B-mode image generated at step S302, the composite image generated at step S307, and the step S305. The displacement and the index calculated in step S308 are displayed in parallel (step S310), and the process ends. Then, the ultrasonic diagnostic apparatus according to the third embodiment further performs the processing after step S202 when new reflected wave data for one frame is stored. Note that the order of processing by the B-mode processing unit 13, the tissue motion information acquisition unit 14a, and the blood flow motion information acquisition unit 14b is not limited to the order shown in FIG. I can do it. Moreover, the case where the process by the B mode process part 13, the tissue movement information acquisition part 14a, and the blood flow movement information acquisition part 14b is performed by a parallel process may be sufficient.

  As described above, in the third embodiment, in the power image obtained by imaging the blood flow power value, the velocity calculation unit 15c tracks speckles between successive power images, thereby obtaining each tracking point. A motion vector is calculated, and the calculated motion vector of each tracking point is calculated as a blood flow velocity. The control unit 17 controls the blood flow velocity to be displayed on the monitor 2 as blood flow motion information.

  That is, according to the third embodiment, by using the power value of blood flow and the speckle pattern in the power image, it can be acquired only by transmitting an ultrasonic beam perpendicular to the blood vessel conventionally. The blood flow velocity can be acquired. Further, according to the third embodiment, the acquired blood flow velocity can be provided to the doctor as an image. Therefore, in the third embodiment, it is possible to further guarantee the accuracy of diagnosis using the blood vessel wall and blood flow motion information.

    In the third embodiment, the index calculation unit 15d calculates an index related to the properties of the blood vessel based on at least one of the tissue motion information and the blood flow motion information, and the control unit 17 sets the index to the monitor 2. Control to display. Therefore, in the third embodiment, using the motion information acquired from the reflected wave signal at the same time (the same reflected wave signal), an index indicating the hardness of the blood vessel is calculated and provided to the doctor. I can do it. Therefore, in the third embodiment, it is possible to facilitate diagnosis by a doctor using the blood vessel wall and blood flow motion information.

  Of the processes described in the first to third embodiments, all or part of the processes described as being performed automatically can be performed manually, or can be performed manually. All or a part of the processing described as can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  As described above, according to the first to third embodiments, it is possible to ensure the accuracy of diagnosis using the motion information of the blood vessel wall and blood flow.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Monitor 3 Input device 10 Apparatus main body 11 Transmission / reception part 12 Frame buffer 13 B mode processing part 14 Doppler processing part 14a Tissue motion information acquisition part 14b Blood flow movement information acquisition part 15 Image processing part 15a Image generation part 15b Image Composition unit 16 Image memory 17 Control unit 18 Internal storage unit

Claims (7)

A single-frame reflected wave signal is generated continuously by causing the ultrasonic probe to perform continuous scanning of a scanning range formed by a plurality of scanning lines after performing ultrasonic transmission / reception on each scanning line once. A transmission / reception unit,
Among the reflected wave signals for each successive frame generated by the transmitting / receiving unit, the tissue motion information is calculated by performing autocorrelation calculation on the reflected wave signals at the same place between adjacent frames. As a tissue exercise information acquisition unit,
It is estimated by performing infinite impulse response type filter processing on the reflected wave signal at the same place in the reflected wave signal for each successive frame used by the tissue movement information acquisition unit to acquire the tissue movement information. A blood flow movement information acquisition unit for acquiring a blood flow power value as blood flow movement information;
A display control unit for controlling the tissue motion information acquired by the tissue motion information acquisition unit and the blood flow motion information acquired by the blood flow motion information acquisition unit to be displayed on a predetermined display unit;
An ultrasonic diagnostic apparatus comprising: The tissue motion information acquisition unit further acquires a tissue displacement calculated by integrating the velocity of the tissue in the time direction as the tissue motion information,
The ultrasonic diagnostic apparatus according to claim 1, wherein the display control unit controls the display of the displacement of the tissue acquired by the tissue motion information acquisition unit on the predetermined display unit. The tissue motion information acquisition unit further acquires, as the tissue motion information, a tissue strain calculated by differentiating the tissue displacement in a spatial direction within a frame,
The ultrasonic diagnostic apparatus according to claim 2, wherein the display control unit controls the strain of the tissue acquired by the tissue motion information acquisition unit to be displayed on the predetermined display unit. In the power image obtained by imaging the blood flow power value, the motion vector of each tracking point is calculated by tracking speckles between successive power images, and the calculated motion vector of each tracking point is used as the blood flow. A speed calculator for calculating the speed of
The display control unit controls the blood flow velocity calculated by the velocity calculation unit to be displayed on the predetermined display unit as the blood flow movement information. The ultrasonic diagnostic apparatus as described in any one.   The transmission / reception unit is configured to perform ultrasonic transmission / reception for one frame at a frame rate in which speckle movement between power images obtained by imaging the blood flow power value is in the same direction as blood movement. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is controlled.   6. The display control unit according to claim 5, wherein the display control unit controls a display interval of each image continuously generated from each of the tissue motion information and the blood flow motion information to be larger than the frame rate. The ultrasonic diagnostic apparatus as described. An index calculation unit that calculates an index related to the properties of a blood vessel based on at least one of the tissue motion information acquired by the tissue motion information acquisition unit and the blood flow motion information acquired by the blood flow motion information acquisition unit Further comprising
The ultrasonic diagnosis according to any one of claims 1 to 6, wherein the display control unit controls the index calculated by the index calculation unit to be displayed on the predetermined display unit. apparatus.

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