JP2011217826A - Ultrasonic diagnostic device and multiple detection program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support an operator so that the position of a multiple artifact generated in an ultrasonic image can be easily discriminated.SOLUTION: A transmission/receiving unit 11 collects reflected wave data while changing a set acoustic velocity used for calculation of receiving delay time so that the position of a focal point of received beam is moved in the depth direction within a subject. A signal processing unit 12 time-serially generates a plurality of image data from the reflected wave data. A contrast calculation unit 13 divides, every time image data are generated, the image data into a plurality of sections, and calculates a contrast value for each section. A multiple determination unit 14 calculates, based on the calculated contrast values, an index value indicating a correlation between the set acoustic velocity and the contrast value for the same section in the plurality of image data. The multiple determination unit 14 compares the index value with a predetermined threshold for each section, and detects a section with an index value smaller than the predetermined threshold as a section in which the multiple artifact is generated.

Description

  The present invention relates to an ultrasonic diagnostic apparatus and a multiple detection program.

  An ultrasonic diagnostic apparatus is an apparatus that captures an image in a subject using ultrasonic waves (see, for example, Patent Document 1). This ultrasonic diagnostic apparatus transmits an ultrasonic signal to a diagnostic region of a subject by an ultrasonic probe having a plurality of piezoelectric vibrators. Then, the ultrasonic diagnostic apparatus receives a reflected wave signal, which is a reflected wave of the transmitted ultrasonic signal, by an ultrasonic probe, and generates an ultrasonic image that is a tomographic image of the diagnostic region based on the reflected wave signal. .

  Conventionally, it is known that various artifacts are generated in an ultrasonic image generated by such an ultrasonic diagnostic apparatus. For example, artifacts generated in an ultrasonic image include multiple artifacts caused by multiple reflections of ultrasonic signals. Examples of the multiple artifact include a multiple reflection caused between the living body and the probe or between the living bodies, and a residual multiplexing mixed from the previous transmission rate.

  FIG. 10 is a diagram for explaining multiple artifacts in an ultrasonic image generated by a conventional ultrasonic diagnostic apparatus. For example, as shown in FIG. 10, after the ultrasonic signal 102 transmitted from the ultrasonic probe 101 is reflected by the blood vessel 103 in the subject, it is reflected by the surface of the ultrasonic probe and returns to the inside of the subject. 103 may be reflected again. As a result, in the ultrasonic image, an artifact 104 due to the blood vessel 103 is generated at a position deeper than the actual position of the blood vessel 103.

  Further, for example, after the ultrasonic signal 105 transmitted from the ultrasonic probe 101 is reflected by the blood vessel 106 at a position deeper than the blood vessel 103, it is reflected by the blood vessel 103 and returns to the blood vessel 106 side. May reflect. As a result, an artifact 107 due to the blood vessel 106 is generated at a position deeper than the actual position of the blood vessel 106 in the ultrasonic image.

  Further, for example, the ultrasonic signal 108 transmitted at the previous transmission rate is reflected by the structure 109 in the subject, and the reflected signal of the reflection is a reflected wave of the ultrasonic signal transmitted at the next transmission rate. May be mixed in. As a result, in the ultrasonic image, an artifact 107 due to the structure 109 is generated at a position where the structure 109 does not actually exist.

  As described above, there are various types of multiple artifacts generated in an ultrasonic image. When multiple artifacts occur in the ultrasonic image, the operator of the ultrasonic diagnostic apparatus needs to determine whether or not the multiple artifacts are occurring at a position that hinders diagnosis. Therefore, the operator manipulates the ultrasound diagnostic apparatus and changes the drive period of the ultrasound signal transmitted to the subject or changes the scanning direction of the ultrasound signal, and the image is drawn on the ultrasound image. By checking whether the display position of each part changes, the position where the multiple artifact has occurred is determined.

JP 2008-264531 A

  However, in the conventional discrimination method described above, the operator needs to operate the ultrasonic diagnostic apparatus after understanding the characteristics of the various multiple artifacts described above. For this reason, the operator cannot easily determine the position of the multiple artifact generated in the ultrasonic image.

  The present invention has been made in view of the above, and is a magnetic resonance imaging apparatus capable of assisting an operator so that the position of multiple artifacts occurring in an ultrasound image can be easily determined. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, the present invention according to claim 1 is directed to an ultrasonic diagnostic apparatus in which a reception delay is performed so that a focal position of a reception beam moves in a depth direction within a subject. Collecting means for collecting reflected wave data while changing a set sound speed used for calculation of time, data generating means for generating a plurality of image data in time series from the reflected wave data collected by the collecting means, and the data Each time image data is generated by the generating means, the generated image data is divided into a plurality of sections, and then a contrast calculating means for calculating a contrast value for each section, and a contrast value calculated by the contrast calculating means. Based on the index value indicating the degree of correlation between the set sound speed and the contrast value for each same section in the plurality of image data. The value calculation means, the index value calculated by the index value calculation means and a predetermined threshold value are compared for each section, and multiple artifacts due to multiple reflection of ultrasonic waves occur in the section where the index value is smaller than the predetermined threshold value And multiple detecting means for detecting as a section that is in the process.

  Further, according to the present invention, the multiplex detection program changes the reflected wave while changing the set sound speed used for calculating the reception delay time so that the focus position of the reception beam moves in the depth direction within the subject. A collection procedure for collecting data, a data generation procedure for generating a plurality of image data in time series from the reflected wave data collected by the collection procedure, and each time image data is generated by the data generation procedure A contrast calculation procedure for calculating a contrast value for each section after dividing the image data into a plurality of sections, and for each same section in the plurality of image data based on the contrast value calculated by the contrast calculation procedure An index value calculating procedure for calculating an index value indicating a degree of correlation between the set sound speed and the contrast value; and the index value calculating procedure. Therefore, a multiple detection procedure for comparing the calculated index value with a predetermined threshold value for each of the sections, and detecting a section with the index value smaller than the predetermined threshold as a section where multiple artifacts due to multiple reflection of ultrasonic waves have occurred. And making the computer execute.

  According to the first and sixth aspects of the present invention, there is an effect that it is possible to assist the operator so that the position of the multiple artifact generated in the ultrasonic image can be easily determined.

FIG. 1 is a functional block diagram illustrating the configuration of the ultrasonic diagnostic apparatus according to the embodiment. FIG. 2 is a diagram (1) for explaining the division of the image data by the contrast calculation unit according to the present embodiment. FIG. 3 is a diagram (2) for explaining the division of the image data by the contrast calculation unit according to the present embodiment. FIG. 4 is a diagram (1) for explaining the detection of multiple artifacts by the multiple determination unit according to the present embodiment. FIG. 5 is a diagram (2) for explaining the detection of multiple artifacts by the multiple determination unit according to the present embodiment. FIG. 6 is a diagram (3) for explaining the detection of multiple artifacts by the multiple determination unit according to the present embodiment. FIG. 7 is a diagram for explaining image display by the display processing unit according to the present embodiment. FIG. 8 is a flowchart illustrating a multiple detection processing procedure performed by the ultrasonic diagnostic apparatus according to the present embodiment. FIG. 9 is a diagram for explaining a modification of the image display according to the present embodiment. FIG. 10 is a diagram for explaining multiple artifacts in an ultrasonic image generated by a conventional ultrasonic diagnostic apparatus.

  Exemplary embodiments of an ultrasonic diagnostic apparatus and a multiple detection program according to the present invention will be described below in detail with reference to the accompanying drawings. In the embodiment described below, an artifact caused by multiple reflection of an ultrasonic signal is referred to as multiple artifact.

  First, the configuration of the ultrasonic diagnostic apparatus 100 according to the present embodiment will be described. FIG. 1 is a functional block diagram illustrating a configuration of an ultrasonic diagnostic apparatus 100 according to an embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus 100 according to the present embodiment includes an ultrasonic probe 1, an input unit 2, a display unit 3, and an apparatus main body 10.

  The ultrasonic probe 1 has a plurality of electronic scanning type piezoelectric vibrators arranged in a line. The plurality of piezoelectric vibrators generate an ultrasonic wave based on a drive signal supplied from a transmission / reception unit 11 included in the apparatus main body 10 to be described later, and receive a reflected wave from the subject and convert it into an electric signal. The ultrasonic probe 1 includes a matching layer provided in the piezoelectric vibrator, a backing material that prevents propagation of ultrasonic waves from the piezoelectric vibrator to the rear, and the like.

  When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject, the transmitted ultrasonic waves are reflected one after another on the discontinuous surface of the acoustic impedance in the body tissue of the subject, and a plurality of piezoelectric elements included in the ultrasonic probe 1. Received as a reflected wave signal by the vibrator. 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. Subject to frequency shift.

  The input unit 2 includes input devices such as a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, and a trackball. The input unit 2 receives various instructions from the operator via these input devices, and transfers the received various instructions to the apparatus main body 10. In the present embodiment, the input unit 2 includes a multiple detection button for receiving a start instruction for starting detection of multiple artifacts from the operator.

  The display unit 3 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus 100 to input various setting requests using the input unit 2 or displays an ultrasonic image generated in the apparatus main body 10. Or display.

  The apparatus main body 10 is an apparatus that generates an ultrasonic image based on a reflected wave signal received by the ultrasonic probe 1. As shown in FIG. 1, the transmission / reception unit 11, signal processing unit 12, contrast calculation unit 13, multiplexing A determination unit 14, a calculation memory 15, a display processing unit 16, an image memory 17, and a control unit 18 are included.

  The transmission / reception unit 11 controls transmission directivity and reception directivity in ultrasonic transmission / reception performed by the ultrasonic probe 1. Specifically, the transmission / reception unit 11 includes a trigger generation circuit, a delay circuit, a pulsar circuit, and the like, and supplies a drive signal to the ultrasonic probe 1. The pulsar circuit repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency. The delay circuit sets the delay time for each piezoelectric vibrator necessary for determining the transmission directivity by focusing the ultrasonic wave generated from the ultrasonic probe 1 into a beam shape for each rate pulse generated by the pulser circuit. give. 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 delay circuit adjusts the transmission direction of the ultrasonic beam arbitrarily by focusing the ultrasonic beam transmitted from the surface of the piezoelectric vibrator by changing the delay time given to each rate pulse.

  The transmission / reception unit 11 includes an amplifier circuit, an A / D converter, an adder, and the like, and performs various processes on the reflected wave signal received by the ultrasonic probe 1 to generate reflected wave data. The amplifier circuit performs a gain correction process for amplifying the reflected wave signals received by the ultrasonic probe 1. The A / D converter A / D converts the reflected wave signal whose gain is corrected. The adder generates reflected wave data by performing addition processing of the reflected wave signal digitized by the A / D converter.

  Here, when the A / D converter performs A / D conversion of the reflected signal, the A / D converter determines reception directivity for each of the reflected wave signals received by the plurality of piezoelectric vibrators included in the ultrasonic probe 1. Give the delay time needed to do. Then, by adjusting the delay time given to each reflected wave signal for each reflected wave signal, the position of the focus of the received beam can be moved in the depth direction within the subject.

For example, assuming that the plurality of piezoelectric vibrators included in the ultrasonic probe 1 are T _i (i = 1, 2, 3,...), The piezoelectric vibrator T _{i is used} when the center of the diameter of the ultrasonic probe 1 is the origin. The delay time Δt _i given to the reflected signal received by is calculated by the following equation (1). Here, X is the depth direction of the coordinates of the focal point X, the piezoelectric vibrator T _i coordinates Y _i in the arrangement direction of the acoustic velocity of the is C, is calculated by equation (1) below.

Δt _i = {(X ² + Y _i ² ) ^1/2 −X} / C (1)

As shown in Expression (1), the delay time Δt _i varies depending on the sound speed C. As the sound velocity C, a propagation velocity in the body of the subject to be diagnosed is set in advance. Here, the sound speed C used for calculating the delay time Δt _i is hereinafter referred to as a set sound speed. That is, by changing the set sound speed used for calculating the delay time for each piezoelectric vibrator, the position of the focal point of the reception beam can be moved in the depth direction within the subject. In this embodiment, the transmission / reception unit 11 collects reflected wave data while changing the set sound speed under the control of the control unit 18 described later.

  The transmission / reception unit 11 has a function capable of instantaneously changing delay information, transmission frequency, transmission drive voltage, number of aperture elements, and the like under the control of the control unit 18 described later. Further, the transmission / reception unit 11 can transmit and receive different waveforms for each frame or rate.

  The signal processing unit 12 receives reflected wave data, which is a processed reflected wave signal subjected to gain correction processing, A / D conversion processing, and addition processing, from the transmission / reception unit 11 and performs logarithmic amplification, envelope detection processing, and the like. Thus, image data is generated. For example, the signal processing unit 12 generates B-mode data in which the signal intensity is expressed by brightness. In addition, the signal processing unit 12 performs frequency analysis on velocity information from the reflected wave data received from the transmission / reception unit 11, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and moves average velocity, dispersion, power, and the like. Generate Doppler data with body information extracted for multiple points. In this embodiment, the signal processing unit 12 generates a plurality of image data in time series from the reflected wave data collected by the transmission / reception unit 11 under the control of the control unit 18 described later.

  The contrast calculation unit 13 divides the generated image data into a plurality of sections each time image data is generated by the signal processing unit 12 under the control of the control unit 18 to be described later, and then sets a contrast value for each section. calculate.

  2 and 3 are diagrams for explaining division of image data by the contrast calculation unit 13 according to the present embodiment. As shown in FIG. 2, for example, the contrast calculation unit 13 divides the image data 20 into m × n pieces of image data 20 by dividing the ultrasonic data in m rows in the scanning direction S and n rows in the depth direction D within the subject. Divide into compartments. Then, the contrast calculation unit 13 calculates the contrast value for each of the m × n sections based on the luminance value of the pixels included in the section. Further, for example, as shown in FIG. 3, the contrast calculation unit 13 may divide the image data 30 into a plurality of sections by dividing the image data 30 in a lattice pattern at a predetermined interval d.

The multi-determination unit 14 sets the sound speed for each same section in the plurality of image data generated by the signal processing unit 12 based on the contrast value calculated by the contrast calculation unit 13 under the control of the control unit 18 described later. An index value indicating the degree of correlation between the contrast value and the contrast value is calculated. Then, the multiple determination unit 14 compares the calculated index value with a predetermined threshold for each section, and detects a section whose index value is smaller than the predetermined threshold as a section in which multiple artifacts are generated.
In general, multiple artifacts are generated by a reflection source at a position different from the focus position of the received beam, and it is known that the intensity of the reflected wave signal hardly changes even if the focus position of the received beam is changed. ing. Therefore, when reflected wave data is collected while moving the focus position of the received beam in the depth direction and image data is generated in time series, multiple reflections occur for each of the generated images. In contrast, the contrast value hardly changes. That is, in the section where multiple reflection occurs, the degree of correlation between the set sound speed and the contrast value is lower than in the section where multiple reflection does not occur.

  In addition to the multiple artifacts, various artifacts are generated in the ultrasonic image. For example, there are those generated by the main lobe, those generated by the side lobe, and those generated by the grating lobe. Here, the main lobe is a beam formed by ultrasonic waves emitted from the piezoelectric vibrator in the direction of the scanning line. Further, the side lobe is a beam formed by ultrasonic waves radiated from the scanning line by a predetermined angle. The grating lobe is synthesized by shifting one wavelength between adjacent piezoelectric vibrators when the wavefronts of ultrasonic waves radiated from a plurality of piezoelectric vibrators arranged in a row are synthesized. It is a beam formed in a direction other than the intended direction.

  4-6 is a figure for demonstrating the detection of the multiple artifact by the multiple determination part 14 which concerns on a present Example. FIG. 4 shows the relationship between the contrast value and the set sound speed when an artifact due to the main lobe or the grating lobe has occurred. FIG. 5 shows the relationship between the contrast value and the set sound speed when artifacts due to side lobes have occurred. FIG. 6 shows the relationship between the contrast value and the set sound speed when multiple artifacts have occurred.

  Artifacts generated by the main lobe, grating lobe, and side lobe are generated by the structure that actually exists in the subject as a reflection source, so the reflected wave signal changes when the focus position of the received beam changes. The strength of the changes greatly. Therefore, as shown in FIGS. 4 and 5, the contrast value generated by the main lobe, the grating lobe, and the side lobe changes greatly when the set sound speed changes.

  On the other hand, as shown in FIG. 6, the amount of change in the contrast value when multiple artifacts occur is small even if the set sound speed changes. The multiple determination unit 14 according to the present embodiment detects whether multiple artifacts have occurred in the image data by using such multiple reflection characteristics.

  In the present embodiment, the multiple determination unit 14 uses the variance value of the contrast value for each set sound speed as an index value indicating the degree of correlation between the set sound speed and the contrast value. For example, if the degree of correlation between the set sound speed and the contrast value is high, the variance value of the contrast value for each set sound speed increases. On the contrary, if the degree of correlation between the set sound speed and the contrast value is low, the variance value of the contrast value for each set sound speed becomes small. That is, in a section where multiple reflection does not occur, the variance value of the contrast value for each set sound speed is small.

  Specifically, in the present embodiment, the multiple determination unit 14 calculates the contrast value for each same section in the plurality of image data generated by the signal processing unit 12 based on the contrast value calculated by the contrast calculation unit 13. Calculate the variance value. Then, the multiple determination unit 14 detects a partition whose calculated variance value is smaller than a predetermined threshold as a partition in which multiple artifacts are generated.

  The arithmetic memory 15 stores various data necessary for processing performed by the contrast calculation unit 13 and the multiple determination unit 14.

  The display processing unit 16 generates an ultrasonic image for display from the image data generated by the signal processing unit 12 and causes the display unit 3 to display the generated ultrasonic image. For example, the display processing unit 16 generates a B-mode image in which the intensity of the reflected wave is represented by luminance from the B-mode data generated by the signal processing unit 12. In addition, the display processing unit 16 uses the Doppler data generated by the signal processing unit 12 to calculate an average velocity image, a dispersion image, a power image, or a combination of these images representing moving body information such as blood flow in the diagnostic region. Generate an image.

  Each time the display processing unit 16 generates a display ultrasonic image, the display processing unit 16 stores the generated ultrasonic image in an image memory 17 described later. Then, the display processing unit 16 reads an ultrasonic image for display from the image memory 17 under the control of the control unit 18 described later, and causes the display unit 3 to display the read ultrasonic image.

  In the present embodiment, the display processing unit 16 has multiple artifacts generated by the multiple determination unit 14 based on the image data generated by the signal processing unit 12 under the control of the control unit 18 described later. Is generated and displayed on the display unit 3.

  FIG. 7 is a diagram for explaining image display by the display processing unit 16 according to the present embodiment. As illustrated in FIG. 6, for example, the display processing unit 16 generates an ultrasound image 72 in which a predetermined color (for example, blue) is added to an area 71 occupied by a section determined to have multiple artifacts. Then, the ultrasonic image 72 is displayed on the display unit 3.

  The image memory 17 stores the ultrasonic image generated by the display processing unit 16. For example, the image memory 17 stores a B-mode image, a Doppler image, and the like.

  The control unit 18 controls the operation of each functional unit included in the ultrasonic diagnostic apparatus 100. For example, the control unit 18 transmits / receives the transmission / reception unit 11, the signal processing unit 12, and the display processing unit 16 based on various instructions received from the operator by the input unit 2 and various control programs read from a storage unit (not shown). The contrast calculation unit 13 and the multiple determination unit 14 are controlled.

  Next, a multiple detection processing procedure performed by the ultrasonic diagnostic apparatus 100 according to the present embodiment will be described. FIG. 8 is a flowchart illustrating a multiple detection processing procedure performed by the ultrasonic diagnostic apparatus 100 according to the present embodiment.

  As shown in FIG. 8, in the present embodiment, when the multiple detection start button of the input unit 2 is pressed by the operator (step S101, Yes), the control unit 18 determines the received beam as described below. The transmission / reception unit 11 is caused to perform an operation of collecting reflected wave data while changing the set sound speed used for calculating the reception delay time so that the focus position moves in the depth direction within the subject.

  First, the control unit 18 controls the transmission / reception unit 11 to set the set sound speed used for calculation of the reception delay time to 1400 m / s (step S102). Thereafter, the control unit 18 controls the contrast calculation unit 13 to start calculating a contrast value (steps S103 to S110 described below).

  The contrast calculation unit 13 first stores the image data for one frame generated by the signal processing unit 12 in the calculation memory 15 (step S103). Subsequently, the contrast calculation unit 13 divides the image data stored in the calculation memory 15 into a plurality of sections (step S104). Subsequently, the contrast calculation unit 13 calculates a spatial luminance dispersion value and a contrast value in each of the divided sections (step S105).

  Thereafter, the contrast calculation unit 13 determines, for each section, whether or not the portion depicted in the section is a living body based on the calculated variance value of brightness (step S106). For example, the contrast calculation unit 13 determines that, for a partition in which the variance value of brightness is within a predetermined range, the portion depicted in the partition is a living body, and the brightness variance value is within the predetermined range. For a section that does not fit in the section, it is determined that the portion depicted in the section is not a living body.

  Subsequently, the contrast calculation unit 13 sets the contrast value to zero (step S107) and stores the contrast value in the calculation memory 15 for the section determined that the portion depicted in the section is not a living body (step S106, No). Save (step S108). On the other hand, for a partition that is determined to be a living body as a portion depicted in the partition (step S106, Yes), the contrast calculation unit 13 calculates a contrast value calculated based on the luminance value of the pixels included in the partition. Save in the memory 15 (step S108).

  And if the contrast value of each division is preserve | saved in the calculation memory 15, the control part 18 will determine whether the setting sound speed set by the transmission / reception part 11 exceeds 1600 m / s (step S109). Here, when the set sound speed is 1600 m / s or less (step S109, No), the control unit 18 adds 20 m / s to the set sound speed held in the transmission / reception unit 11 (step S110).

  After adding 20 m / s to the set sound speed, the control unit 18 controls the contrast calculation unit 13 to further store the image data for one frame generated by the signal processing unit 12 in the calculation memory 15 (step S103). (Return) Then, the contrast calculation unit 13 executes the processes of steps S104 to S108 described above.

  Thus, until the set sound speed exceeds 1600 m / s, the contrast calculation unit 13 repeats the calculation of the contrast value. When the set sound speed exceeds 1600 m / s (step S109, Yes), the control unit 18 controls the multiple determination unit 14 to start detection of multiple artifacts (steps S111 to S113 shown below). ).

  Specifically, the multiple determination unit 14 first reads all the contrast values stored in the calculation memory 15, and based on the read contrast values, the same in a plurality of image data generated by the signal processing unit 12 A variance of contrast values is calculated for each section (step S111).

  Subsequently, the multiple determination unit 14 compares the calculated variance value with a predetermined threshold value for each section (step S112). If there is a partition whose variance value is smaller than the predetermined threshold (Yes at Step S112), the multiple determination unit 14 detects the partition as a partition where multiple artifacts are generated (Step S113). Thereafter, the control unit 18 controls the display processing unit 16 to generate an ultrasonic image in which the display mode of the section detected by the multiple determination unit 14 is changed and display the ultrasonic image on the display unit 3 (step S114).

  On the other hand, when there is no partition whose variance value is smaller than the predetermined threshold (No in step S112), the multiple determination unit 14 does not detect a partition in which multiple artifacts are generated. In this case, the control unit 18 controls the display processing unit 16 so that a normal ultrasonic image is generated from the image data generated by the signal processing unit 12 and displayed on the display unit 3. Is controlled (step S115).

  Here, the case where the set sound speed is changed between 1400 m / s and 1600 m / s has been described, but the range of the set sound speed is not limited to this. It can be set as appropriate. Further, the unit for accelerating the set sound speed is not limited to 20 m / s, and can be appropriately set according to, for example, required accuracy of multiplex detection.

  As described above, in this embodiment, the transmission / reception unit 11 changes the reflected wave data while changing the set sound speed used to calculate the reception delay time so that the focus position of the reception beam moves in the depth direction within the subject. To collect. Further, the signal processing unit 12 generates a plurality of image data in time series from the reflected wave data collected by the transmission / reception unit 11. Further, every time image data is generated by the signal processing unit 12, the contrast calculation unit 13 divides the generated image data into a plurality of sections and then calculates a contrast value for each section. In addition, the multiple determination unit 14 indicates the degree of correlation between the set sound speed and the contrast value for each same section in the plurality of image data generated by the signal processing unit 12 based on the contrast value calculated by the contrast calculation unit 13. An index value is calculated. Then, the multiple determination unit 14 compares the calculated index value with a predetermined threshold for each section, and detects a section whose index value is smaller than the predetermined threshold as a section in which multiple artifacts are generated.

  Therefore, according to the present embodiment, even when the operator does not completely understand the characteristics of various multiple artifacts, the position where the multiple artifacts are generated can be automatically indicated to the operator. Further, according to the present embodiment, it is not necessary for the operator to perform operations such as changing the driving cycle of the ultrasonic signal and the scanning direction in order to determine the position of the multiple artifact. That is, according to the present embodiment, it is possible to assist the operator so that the position of multiple artifacts occurring in the ultrasonic image can be easily determined.

  Further, in the present embodiment, the display processing unit 16 changes the display mode of the section in which the multiple determination unit 14 determines that multiple artifacts are generated based on the image data generated by the signal processing unit 12. An ultrasonic image is generated and displayed on the display unit 3.

  Therefore, according to the present embodiment, the operator can easily confirm the position of the multiple artifacts only by looking at the ultrasonic image displayed on the display unit 3. This makes it possible to assist the operator so that the position of the multiple artifacts occurring in the ultrasound image can be more easily determined.

  In the present embodiment, the input unit 2 receives from the operator a start instruction for starting detection of multiple artifacts. Further, when a start instruction is received by the input unit 2, the transmission / reception unit 11 performs an operation of collecting reflected wave data while changing the set sound speed.

  Therefore, according to the present embodiment, since the ultrasonic image indicating the position of the multiple artifact is displayed only when the operator desires, the operator is supported without interfering with the conventional image diagnosis by the ultrasonic diagnostic apparatus. It becomes possible.

  In the above-described embodiment, a case has been described in which it is determined whether multiple artifacts have occurred based on one threshold value. However, the present invention is not limited to this. For example, the accuracy with which multiple artifacts are generated may be determined step by step based on a plurality of threshold values set stepwise.

  In this case, when the multiple determination unit 14 detects a section in which multiple artifacts are generated, the multiple determination unit 14 determines the probability that multiple artifacts are generated using a plurality of threshold values set in stages. In addition, the display processing unit 16 changes the display mode of the section determined to have multiple artifacts in a stepwise manner according to the accuracy detected by the multiple determination unit 14.

  For example, the multiplex determination unit 14 sets a plurality of threshold values so as to have different values in stages, and compares the variance value of the contrast value calculated for each section with each threshold value to multiplex each section. Determine the level of accuracy with which the artifact is occurring. That is, the level of accuracy of multiple artifacts increases as the variance value decreases and decreases as the variance value increases. The display processing unit 16 displays the sections determined to have multiple artifacts in different colors for each level of accuracy.

  According to this modification, since the probability that multiple artifacts have occurred is presented, the position where the operator is likely to have multiple artifacts and the possibility that multiple artifacts have occurred are low. The position can be identified. As a result, the operator can easily grasp the influence of the multiple artifacts on the image diagnosis.

  Further, in the above-described embodiment, as shown in FIG. 7, the case has been described in which the display unit 3 displays an ultrasonic image in which the display mode of the section where it is determined that multiple artifacts have occurred. However, the present invention is not limited to this. For example, an ultrasonic image showing a section where multiple artifacts are generated may be displayed, and a normal ultrasonic image may be displayed.

  FIG. 9 is a diagram for explaining a modification of the image display according to the present embodiment. As shown in FIG. 9, in this case, the display processing unit 16 does not change the display mode from the ultrasound image 92 in which the display mode of the section 91 in which it is determined that the artifact due to multiple reflection has occurred. Each of the ultrasonic images 93 is displayed on the display unit 3. At this time, an ultrasonic image is generated from the image data generated by the signal processing unit 12 as in the conventional case, and the ultrasonic image is displayed on the display unit 3. Then, for example, as shown in FIG. 9, the display processing unit 16 displays an image showing multiple artifacts and a normal ultrasonic image side by side on the display unit 3.

  According to this modified example, since an ultrasonic image showing multiple artifacts and a normal ultrasonic image are respectively displayed, the operator can efficiently diagnose by comparing the ultrasonic images. Can do.

  The configuration of the ultrasonic diagnostic apparatus 100 described in the above embodiment can be changed to various forms without departing from the gist. For example, all or some of the functions of the transmission / reception unit 11, the signal processing unit 12, the contrast calculation unit 13, the multiple determination unit 14, the display processing unit 16, and the control unit 18 illustrated in FIG. The function of the ultrasonic diagnostic apparatus 100 can also be realized by causing a computer to execute.

  At this time, the multiple detection program implemented as software may be preinstalled in the computer device, recorded on a removable recording medium such as a magnetic disk, a magneto-optical disk, an optical disk, or a semiconductor memory, or via a network. And may be installed on the computer device as appropriate.

DESCRIPTION OF SYMBOLS 100 Ultrasonic diagnostic apparatus 10 Apparatus main body 11 Transmission / reception part 12 Signal processing part 13 Contrast calculation part 14 Multiple determination part 16 Display processing part 18 Control part

Claims (6)

A collecting means for collecting reflected wave data while changing a set sound speed used for calculation of the reception delay time so that the position of the focus of the reception beam moves in the depth direction in the subject;
Data generating means for generating a plurality of image data in time series from the reflected wave data collected by the collecting means;
Contrast calculation means for calculating a contrast value for each section after dividing the generated image data into a plurality of sections each time image data is generated by the data generation means;
Index value calculating means for calculating an index value indicating a degree of correlation between the set sound speed and the contrast value for each same section in the plurality of image data based on the contrast value calculated by the contrast calculating means;
The index value calculated by the index value calculation means and a predetermined threshold are compared for each section, and the section where the index value is smaller than the predetermined threshold is determined as a section where multiple artifacts due to multiple reflections of ultrasonic waves have occurred. An ultrasonic diagnostic apparatus comprising: multiple detection means for detecting.   Based on the image data generated by the data generation means, an ultrasonic image in which the display mode of the section where the multiple artifact is determined to be generated by the multiple detection means is generated and displayed on the display unit. The ultrasonic diagnostic apparatus according to claim 1, further comprising display processing means. The multiple detection means, when detecting a section where the multiple artifacts are generated, using a plurality of thresholds set in stages, determine the accuracy of the multiple artifacts are generated,
3. The display processing unit according to claim 2, wherein the display processing unit changes the display mode of the section in which it is determined that the multiple artifact is generated in a stepwise manner in accordance with the accuracy detected by the multiple detection unit. Ultrasound diagnostic equipment.   The display processing unit causes the display unit to display an ultrasonic image in which a display mode of a section where it is determined that an artifact due to multiple reflection has occurred and an ultrasonic image in which the display mode is not changed are respectively displayed on the display unit. The ultrasonic diagnostic apparatus according to claim 1, 2, or 3. Further comprising a receiving means for receiving from the operator a start instruction to start detecting the multiple artifacts,
The said collection means performs the operation | movement which collects the said reflected wave data, changing the said setting sound speed, when the said start instruction is received by the said reception means. The ultrasonic diagnostic apparatus as described in one. A collection procedure for collecting reflected wave data while changing the set sound speed used for calculating the reception delay time so that the position of the focus of the reception beam moves in the depth direction within the subject;
A data generation procedure for generating a plurality of image data in time series from the reflected wave data collected by the collection procedure;
Each time image data is generated by the data generation procedure, a contrast calculation procedure for calculating a contrast value for each section after dividing the generated image data into a plurality of sections;
An index value calculating procedure for calculating an index value indicating a degree of correlation between the set sound speed and the contrast value for each same section in the plurality of image data based on the contrast value calculated by the contrast calculating procedure;
The index value calculated by the index value calculation procedure is compared with a predetermined threshold value for each section, and the section where the index value is smaller than the predetermined threshold is determined as a section where multiple artifacts due to multiple reflection of ultrasonic waves have occurred. A multiplex detection program for causing a computer to execute a multiplex detection procedure for detection.

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