JP2012217583A - Ultrasonograph and image generation control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate an ultrasonic image having high temporal resolution with high image quality by using a parallel simultaneous reception method.SOLUTION: An ultrasonograph includes a control part 18, a detection part 13a, a correction part 13c, and an image generation part 16. The control part 18 controls a transmission part 11 and a reception part 12, simultaneously receives at least two reflection wave beams among the reflection wave beams of transmitted ultrasonic beams, and then, performs preliminary scanning to receive the reflection wave beam of a position corresponding to the reflection wave beam to be received in main scanning. The detection part 13a detects the reception sensitivities of the first reflection wave beam received in the main scanning and the second reflection wave beam corresponding to the position of the first reflection wave beam received in the preliminary scanning. The correction part 13c compares the reception sensitivities of the first and second reflection beams and corrects the sensitivities of the respective reflection wave beams in the main scanning. The image generation part 16 generates an ultrasonic image, based on the sensitivity-corrected reflection beams.

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus and an image generation control program.

  Conventionally, in an ultrasonic diagnostic apparatus, a parallel simultaneous reception method is performed in order to improve a frame rate (time resolution). The parallel simultaneous reception method simultaneously receives reflected waves (received ultrasonic waves) of ultrasonic waves (transmitted ultrasonic waves) transmitted in a predetermined direction of a subject from a plurality of directions adjacent to the predetermined direction, so that per unit time This is a method for increasing the amount of data.

  However, in the parallel simultaneous reception method, the central axis of the transmission beam is different from the central axis of the reception beam. For this reason, in the parallel simultaneous reception method, the transmission / reception sensitivity deteriorates and uniform transmission / reception sensitivity cannot be obtained. As a result, the ultrasonic image at the time of parallel simultaneous reception has a stripe pattern and the image quality deteriorates. It is known.

  For this reason, when performing parallel simultaneous reception, a method of performing weighted addition between a plurality of reception beams, a gain adjustment method of adjusting the gain of a reception beam (reception signal), and a transmission / reception beam for each frame of an ultrasonic image A method of removing the stripe pattern by shifting the pattern is performed.

  However, the method of performing weighted addition is to add a plurality of received beams by weights that are empirically determined. The gain adjustment method adjusts the gain of reception sensitivity according to the reception signal having low reception sensitivity. In addition, in the method of shifting the transmission / reception beam pattern, since it is necessary to repeatedly perform ultrasonic transmission / reception in order to generate one ultrasonic image, the frame rate is decreased.

Japanese Patent Laid-Open No. 61-135641 JP-A-6-225883 JP-A-10-118063

  The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus and an image generation control program that can generate an ultrasonic image with high temporal resolution with high image quality using a parallel simultaneous reception method.

  The ultrasonic diagnostic apparatus according to the embodiment includes a transmission / reception unit, a control unit, a detection unit, a correction unit, and an image generation unit. The transmitting / receiving unit performs ultrasonic scanning by transmitting an ultrasonic beam and receiving a reflected wave beam of the transmitted ultrasonic beam. The control unit transmits the ultrasonic beam before executing the main scan for capturing an ultrasonic image by the parallel simultaneous reception method, and at least two reflected waves of the reflected wave beam of the ultrasonic beam are transmitted. By simultaneously receiving the beams, the transmission / reception unit is controlled so as to execute a preliminary scan for receiving a reflected wave beam at a position corresponding to the reflected wave beam received in the main scanning. The detection unit detects reception sensitivity of the first reflected wave beam received by the main scanning, and further, a second reflected wave corresponding to the position of the first reflected wave beam received by the preliminary scanning. Detect the beam reception sensitivity. The correction unit increases or decreases the reception sensitivity of each reflected wave beam received in the main scan by comparing the reception sensitivity of the first reflected wave beam with the reception sensitivity of the second reflected wave beam. Perform sensitivity correction. The image generation unit generates an ultrasonic image using each reflected wave beam of the main scan whose sensitivity is corrected by the correction unit.

FIG. 1 is a diagram for explaining an example of the overall configuration of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram for explaining the parallel simultaneous reception method. FIG. 3 is a diagram (1) for explaining the non-uniformity of the transmission / reception sensitivity in the parallel simultaneous reception method. FIG. 4 is a diagram (2) for explaining the non-uniformity of transmission / reception sensitivity in the parallel simultaneous reception method. FIG. 5 is a diagram (1) for explaining a conventional method for eliminating non-uniformity of transmission / reception sensitivity in the parallel simultaneous reception method. FIG. 6 is a diagram (2) for explaining the conventional method for eliminating the non-uniformity of the transmission / reception sensitivity in the parallel simultaneous reception method. FIG. 7 is a diagram (1) for explaining an example of the preliminary scan executed by the control unit according to the first embodiment. FIG. 8 is a diagram (2) for explaining an example of the preliminary scan executed by the control unit according to the first embodiment. FIG. 9 is a diagram for explaining the correction unit according to the first embodiment. FIG. 10 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 11 is a diagram for explaining the second embodiment. FIG. 12A is a flowchart for explaining a correction control process during a preliminary scan of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 12B is a flowchart for explaining the correction control process during the main scan of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 13 is a diagram for explaining the third embodiment. FIG. 14 is a diagram (1) for explaining the preliminary scan in the three-dimensional scan. FIG. 15 is a diagram (2) for explaining the preliminary scan in the three-dimensional scan.

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

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

  The ultrasonic probe 1 has a plurality of piezoelectric vibrators, and the plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission unit 11 included in the apparatus main body 10 to be 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 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 by the moving blood flow or the surface of the heart wall depends on the velocity component of the moving object in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift.

  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 it to the apparatus body 10. Transfer various setting requests.

  Here, the input device 3 according to the first embodiment receives imaging conditions by the parallel simultaneous reception method, a correction request for data received by the parallel simultaneous reception method, and the like from the operator. Note that imaging conditions and correction requests received from the operator by the input device 3 according to the first embodiment will be described in detail later.

  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, and 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 unit 11, a reception unit 12, a reception data processing unit 13, a B-mode processing unit 14, a Doppler processing unit 15, an image generation unit 16, and an image memory. 17, a control unit 18, and an internal storage unit 19.

  The transmission 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 rate pulses for forming transmission ultrasonic waves at a predetermined 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. 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.

  That is, the transmission delay circuit controls the position of the focal point (transmission focus) in the depth direction of ultrasonic transmission by giving a transmission delay time to each rate pulse generated by the pulser circuit. Further, the transmission 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 18 described later. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching the value or a mechanism for electrically switching a plurality of power supply units.

  The receiving unit 12 includes an amplifier circuit, an A / D converter, a reception delay circuit, an adder, and the like, and performs various processing on the reflected wave beam (received beam) received by the ultrasonic probe 1 to generate reflected wave data. Is generated. The amplifier circuit amplifies the reflected wave beam 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 the addition process of the reflected wave signal given the reception delay time by the reception delay circuit to generate the reflected wave data. 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.

  As described above, the transmission unit 11 and the reception unit 12 control transmission directivity and reception directivity in transmission / reception of ultrasonic waves. For example, the transmission unit 11 gives transmission directivity by controlling the number and position (transmission opening) of the piezoelectric vibrators used at the time of transmission of the ultrasonic beam by the scan control function of the control unit 18 described later. That is, the transmission unit 11 determines the position of the central axis of the ultrasonic beam in the scanning direction of the ultrasonic probe 1 by controlling the transmission aperture. In addition, the receiving unit 12 gives reception directivity by controlling the number and position of the piezoelectric vibrators used when receiving the reflected wave beam, that is, the receiving aperture, by the scan control function of the control unit 18 described later. That is, the receiving unit 12 determines the position of the reflected wave beam received by the ultrasonic probe 1 by controlling the receiving aperture.

  Here, the transmission unit 11 and the reception unit 12 according to the first embodiment execute the parallel simultaneous reception method by a scan control function of the control unit 18 described later. The parallel simultaneous reception method is a photographing method for improving the frame rate (time resolution). In the parallel simultaneous reception method, the amount of data per unit time is increased by simultaneously receiving the reflected wave beam of the ultrasonic beam transmitted in a predetermined direction of the subject P from a plurality of directions adjacent to the predetermined direction.

  Hereinafter, as an example of the parallel simultaneous reception method, 8-beam parallel simultaneous reception in which eight reflected wave beams are simultaneously received by one ultrasonic beam will be described with reference to FIG. FIG. 2 is a diagram for explaining the parallel simultaneous reception method. In FIG. 2, the scanning direction is shown as the horizontal axis and the depth direction is shown as the vertical axis. In the following description, the reflected wave beam is referred to as a reception beam.

For example, when performing 8-beam parallel simultaneous reception, the ultrasonic probe 1 transmits an ultrasonic beam in the depth direction of the test P under the control of the transmission unit 11 via the control unit 18. Then, the ultrasonic probe 1 controls the reception unit 12 via the control unit 18 to receive a reception beam by the ultrasonic beam (transmission ultrasonic wave) from eight directions adjacent to the depth direction to which the ultrasonic beam is transmitted. Receive at the same time. In FIG. 2A, the central axis in the depth direction of the ultrasonic beam transmitted at the first time is indicated by a solid line arrow, and the reflected wave beam simultaneously received at the first time is indicated by a broken line arrow. That is, as shown in FIG. 2A, the ultrasonic probe 1 receives the reception beam ₁₁ to the reception beam ₁₈ in the first transmission / reception. Specifically, the ultrasonic probe 1 has eight reception beams ₁₁ to ₁₈ at positions spaced by a predetermined interval (d) along the scanning direction with the central axis of the first ultrasonic beam as the center. Receive.

Then, the transmission unit 11 transmits the transmission aperture so that the central axis of the ultrasonic beam transmitted for the second time moves from the central axis of the ultrasonic beam transmitted for the first time by the width of eight reception beams in the scanning direction. Select. That is, the central axis of the second ultrasonic beam is moved by “7 × d” along the scanning direction from the central axis of the second ultrasonic beam by the transmitter 11. Thereby, the ultrasonic probe 1, as shown in FIG. 2 (B), and transmits a second ultrasonic beam (see solid line arrows in the figure), in the second transmitting and receiving, a receive beam ₂₁ to Receive beam ₂₈ (see dashed arrow in the figure) is received. Specifically, the ultrasonic probe 1 has eight reception beams ₂₁ to ₂₈ at positions separated by a predetermined interval (d) along the scanning direction with the central axis of the second ultrasonic beam as the center. Receive.

By repeating such transmission and reception, for example, four times, as shown in FIG. 2C, the ultrasonic scanning (scanning) of the region of interest of the subject P is completed, and the reception beam ₁₁ to the reception beam ₁₈ are received. The beam ₂₁ to the reception beam ₂₈ , the reception beam ₃₁ to the reception beam _38, and the reception beam ₄₁ to the reception beam ₄₈ are received by the ultrasonic probe 1, and these reception beams become reflected wave data at the reception unit 12.

  Returning to FIG. 1, the reception data processing unit 13 includes a detection unit 13a, a detection data storage unit 13b, and a correction unit 13c, and the reception unit 12 processes the reflected wave beam (reception beam) through the processing of these units. Sensitivity correction processing is performed on the reflected wave data generated from (1). The detection unit 13a, the detection data storage unit 13b, and the correction unit 13c will be described in detail later.

  The B-mode processing unit 14 receives the reflected wave data from the receiving unit 12, performs logarithmic amplification, envelope detection processing, and the like, and generates data (B-mode data) in which the signal intensity is expressed by brightness. .

  The Doppler processing unit 15 performs frequency analysis on velocity information from the reflected wave data received from the reception unit 12, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and mobile object information such as average velocity, dispersion, and power Is generated for multiple points (Doppler data).

  Note that the B-mode processing unit 14 and the Doppler processing unit 15 according to the present embodiment can process both two-dimensional reflected wave data and three-dimensional reflected wave data.

  The B-mode processing unit 14 according to the present embodiment generates B-mode data from the reflected wave data that has been subjected to sensitivity correction processing by the reception data processing unit 13. Further, the Doppler processing unit 15 according to the present embodiment generates Doppler data from the reflected wave data that has been subjected to sensitivity correction processing by the reception data processing unit 13.

  The image generation unit 16 generates an ultrasound image from the data generated by the B mode processing unit 14 and the Doppler processing unit 15. That is, the image generation 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 B-mode processing unit 14. In addition, the image generation unit 16 generates an average speed image, a dispersed image, a power image, or a color Doppler image representing a combination of these from the Doppler data generated by the Doppler processing unit 15.

  Here, the image generation unit 16 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 16 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 16 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 image generation unit 16 generates a composite image in which character information, scales, body marks, and the like of various parameters are combined with the ultrasonic image.

  The image generation unit 16 can generate a three-dimensional B-mode image by performing coordinate conversion on the three-dimensional B-mode data generated by the B-mode processing unit 14. The image generation unit 16 can generate a three-dimensional color Doppler image by performing coordinate conversion on the three-dimensional Doppler data generated by the Doppler processing unit 15.

  The image memory 17 is a memory that stores ultrasonic image data generated by the image generation unit 16. The image memory 17 can also store data generated by the B-mode processing unit 14 and the Doppler processing unit 15.

  The internal storage unit 19 stores a control program for performing ultrasonic transmission / reception, image processing and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), various data such as a diagnostic protocol and various body marks. To do. The internal storage unit 19 is also used for storing image data stored in the image memory 17 as necessary.

  The control unit 18 controls the entire processing of the ultrasonic diagnostic apparatus. Specifically, the control unit 18 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 19. 12. Control processing of the reception data processing unit 13, the B-mode processing unit 14, the Doppler processing unit 15, and the image generation unit 16. The control unit 18 also controls the monitor 2 to display on the monitor 2 an ultrasonic image stored in the image memory 17, a GUI for designating various processes performed by the reception data processing unit 13, and the like.

  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 captures an ultrasonic image by the parallel simultaneous reception method described above.

  However, in the parallel simultaneous reception method, since the central axis of the transmitted ultrasonic beam is different from the central axis of the received beam, the transmission / reception sensitivity deteriorates toward the outer side of the central axis of the ultrasonic beam, and uniform transmission / reception is performed. Sensitivity could not be obtained. 3 and 4 are diagrams for explaining the non-uniformity of the transmission / reception sensitivity in the parallel simultaneous reception method.

  The ultrasonic beam is not transmitted from one piezoelectric vibrator of the ultrasonic probe 1, but is transmitted from a predetermined number of piezoelectric vibrators selected as transmission apertures to give transmission directivity as described above. Formed by a plurality of ultrasonic waves. That is, the ultrasonic beam transmitted from the transmission aperture converges as it approaches the focal point, and spreads away from the focal point. As a result, the sound pressure of the transmission sound field at the end of the ultrasonic beam is smaller than the sound pressure at the center of the ultrasonic beam.

  Therefore, the sound pressure of the reception beam received in the first transmission / reception described with reference to FIG. 2A decreases as the distance from the central axis of the ultrasonic beam increases as shown in FIG. Become. Also, the sound pressure of each of the received beams received by the four transmissions / receptions described with reference to FIG. 2C periodically increases / decreases along the scanning direction, as shown in FIG. 3B. As a result, the sensitivity unevenness of the reception sensitivity occurs periodically.

  That is, if the parallel simultaneous reception directions are two directions adjacent to the central axis, the transmission sound pressure in the vicinity of the central axis is substantially uniform, so that the reception sensitivity is uniform in the scanning direction. However, when the parallel simultaneous reception direction is set to three or more directions, the reception sensitivity becomes non-uniform in the scanning direction. Such sensitivity unevenness along the scanning direction is a striped artifact in the ultrasonic image.

Further, the non-uniformity of transmission / reception sensitivity will be described with reference to FIG. 4 by taking as an example a case where four reception beams are simultaneously received in one transmission / reception (four-beam parallel simultaneous reception). In FIG. 4A, four reception beams simultaneously received by the first transmission / reception are shown as “reception beam ₁₁ to reception beam ₁₄ ”. In FIG. 4A, the shape of the ultrasonic beam transmitted from the transmission aperture is non-uniform around the central axis by the shape of the transmitted sound field (two arcs in the figure). See). In FIG. 4A, the reception beam ₁₁ to the reception beam ₁₄ indicate that the reception sensitivity is nonuniform due to the shape of the transmission sound field. That is, as shown in FIG. 4A, the reception sensitivities of the reception beam ₁₁ and the reception beam ₁₄ are lower than the reception sensitivities of the reception beam ₁₂ and the reception beam ₁₃ .

Assume that the transmission / reception described with reference to FIG. 4A is performed four times while shifting the transmission aperture. In such a case, the reception sensitivities of the reception beam ₁₁ to reception beam ₁₄ , reception beam ₂₁ to reception beam ₂₄ , reception beam ₃₁ to reception beam ₃₄ , reception beam ₄₁ to reception beam ₄₄ are as shown in FIG. It periodically increases or decreases along the scanning direction, and becomes a factor of striped pattern artifacts in the ultrasonic image.

Further, the non-uniformity of the reception beam occurs not only for each reception beam but also in the depth direction of the reception beam. That is, as shown in FIG. 4C, the transmission sound pressure in the reception direction of the reception beam ₁₁ varies depending on the depth direction. For this reason, the reception sensitivity of the reception beam ₁₁ is different at each point in the depth direction. On the other hand, as shown in FIG. 4C, the transmission sound pressure in the reception direction of the reception beam ₁₂ is substantially uniform in the depth direction. For this reason, the reception sensitivity of the reception beam ₁₂ is substantially uniform at each point in the depth direction.

  The difference in the reception sensitivity in the depth direction within the same reception beam described with reference to FIG. 4C also causes a striped pattern artifact in the ultrasonic image.

  For this reason, when performing parallel simultaneous reception, various methods have been employed in order to eliminate non-uniformity in transmission / reception sensitivity and reduce artifacts in the ultrasonic image. As a conventional method for eliminating the non-uniformity of transmission / reception sensitivity, for example, a method of performing weighted addition between a plurality of reception beams is known. However, the method of performing weighted addition is to add a plurality of received beams by weight determined empirically, and to ensure uniform reception sensitivity in the parallel simultaneous reception method executed under various imaging conditions. Not the way.

  In addition, as a conventional method for eliminating the non-uniformity of the transmission / reception sensitivity, a gain adjustment method for adjusting the gain of the reception beam (reception signal) or a striped pattern is removed by shifting the transmission / reception beam pattern for each frame of the ultrasonic image. The method of doing is known. 5 and 6 are diagrams for explaining a conventional method for eliminating non-uniformity of transmission / reception sensitivity in the parallel simultaneous reception method.

  As shown in FIG. 5, in the gain adjustment method, the reception sensitivity of the reception beam whose reception sensitivity is reduced around the central axis of the ultrasonic beam is reduced, and the reception gain for uniformly reducing the gain of the reception sensitivity near the center is set to each reception beam. Is a method of generating a combined beam in accordance with the receiving sensitivity of the outer receiving beam. In other words, the gain adjustment method uses the amplifier circuit of the receiving unit 12 to adjust the gain of the reception sensitivity in accordance with the reception signal with low reception sensitivity.

  However, with the gain adjustment method, the overall reception sensitivity is lowered, and the image quality of the ultrasonic image is lowered. Further, in the gain adjustment method, the same gain is applied to the same reception beam as a whole, so that different reception sensitivities for each depth cannot be made uniform. As a gain adjustment method, in addition to the method illustrated in FIG. 5, a transmission sound field of an ultrasonic beam is obtained by calculation, and the same reception beam is calculated based on the transmission sound field obtained by calculation. There is also a method of multiplying different gains for each depth. However, the gain used in this gain adjustment method is an ideal gain in calculation, and is not a gain reflecting actual biological conditions.

The shift method is a method of generating a combined beam by simultaneously receiving a predetermined number of received beams while shifting the transmitted beams by the predetermined interval (d) and then adding the received beams at the same position. For example, in the case of performing the shift method, after the reception unit 12 receives the reception beam ₁₁ to the reception beam ₁₈ in the first transmission / reception, in the second transmission / reception, as illustrated in FIG. The central axis of the ultrasonic beam is moved by a predetermined interval (d). And the receiving part 12 receives the receiving beam ₂₁ -the receiving beam _28, as shown to (A) of FIG. Here, as shown in FIG. 6A, the reception beam ₂₁ to the reception beam ₂₇ are in the same position as the reception beam ₁₂ to the reception beam ₁₈ . By repeating such processing, the reception sensitivity of the combined beam obtained by combining a plurality of reception beams received at the same position and having different reception sensitivities becomes substantially uniform as shown in FIG.

  However, in the shift method, for example, since the ultrasonic beam shifted by “7 × d” can be shifted only by “d”, the frame rate (time resolution) is lowered. Furthermore, the shift method cannot be applied to imaging fast-moving tissue because the frame rate decreases.

  Thus, when the parallel simultaneous reception method is performed, a striped pattern is generated in the ultrasonic image due to different transmission / reception sensitivities. However, even if the striped pattern is eliminated by the above-described conventional method, the image quality may be deteriorated or the frame rate may be decreased.

  Accordingly, the ultrasonic diagnostic imaging apparatus according to the first embodiment uses the parallel simultaneous reception method to generate an ultrasonic image with high temporal resolution with high image quality, and the control unit 18 and received data processing described below. The processing of unit 13 is executed.

  First, in the first embodiment, a preliminary scan is executed under the control of the control unit 18. That is, the control unit 18 controls the transmission unit 11 and the reception unit 12 that perform ultrasonic scanning by transmitting an ultrasonic beam and receiving a reflected wave beam of the transmitted ultrasonic beam. The preliminary scan (preliminary scan) described is executed. Specifically, the control unit 18 transmits an ultrasonic beam before executing a main scan (main scan) for capturing an ultrasonic image by the parallel simultaneous reception method, and a reflected wave beam of the ultrasonic beam. Of these, by simultaneously receiving at least two reflected wave beams, a preliminary scan (preliminary scan) for receiving a reflected wave beam at a position corresponding to the reflected wave beam received in the main scan (main scan) is executed. The transmitter 11 and the receiver 12 are controlled. More specifically, the control unit 18 determines each region formed by a plurality of reflected wave beams at predetermined intervals received simultaneously by a plurality of ultrasonic beams sequentially transmitted along the scanning direction in the main scan. Then, preliminary scanning (preliminary scanning) is executed by controlling the transmitting unit 11 and the receiving unit 12 so as to scan with a plurality of ultrasonic beams separated by a predetermined interval along the scanning direction. In other words, the control unit 18 is formed by a plurality of reflected wave beams (received beams) at predetermined intervals (d) that are simultaneously received by the ultrasonic beams sequentially transmitted along the scanning direction in the main scan. Each region is scanned with a plurality of ultrasonic beams, and at least two reflected wave beams at a predetermined interval (d) are simultaneously received by each of the plurality of ultrasonic beams. A preliminary scan (preliminary scan) for receiving a reflected wave beam at the same position as the reflected wave beam is executed.

  Specifically, when the main scan is a two-dimensional scan, the control unit 18 simultaneously receives two reflected wave beams that are symmetric (line symmetric) with respect to the central axis of each ultrasonic beam in the preliminary scan. Thus, the transmitter 11 and the receiver 12 are controlled. 7 and 8 are diagrams for explaining an example of the preliminary scan executed by the control unit according to the first embodiment.

  For example, when performing 8-beam parallel simultaneous reception at a predetermined interval (d), the control unit 18, as shown in FIG. 7, receives eight received beams (received beams 2 a to 2- 2h) is scanned by four ultrasonic beams, and two reflected wave beams at a predetermined interval (d) are simultaneously received by each of the four ultrasonic beams. A preliminary scan for receiving the reflected wave beam (received beams 1a to 1h) at the same position as each reflected wave beam received in the scan is executed.

  That is, by performing the preliminary can illustrated in FIG. 7, the receiving unit 12 simultaneously receives the reception beams 1a and 1b at the same positions as the reception beams 2a and 2b by the first transmission / reception. Then, the reception unit 12 simultaneously receives the reception beams 1c and 1d at the same position as the reception beams 2c and 2d by the second transmission / reception by the ultrasonic beam that has moved the central axis by a predetermined interval (d) from the first central axis. Receive. Then, the reception unit 12 simultaneously receives the reception beams 1e and 1f at the same position as the reception beams 2e and 2f by the third transmission / reception by the ultrasonic beam that has moved the central axis by a predetermined interval (d) from the second central axis. Receive. Then, the reception unit 12 simultaneously receives the reception beams 1g and 1h at the same position as the reception beams 2g and 2h by the fourth transmission / reception by the ultrasonic beam that has moved the central axis by a predetermined interval (d) from the third central axis. Receive.

  Further, in the case of performing four-beam parallel simultaneous reception at a predetermined interval (d), as shown in FIG. 8, the control unit 18 receives four received beams (received beam 2a) simultaneously received by one transmission / reception of the main scan. -2d) by scanning the region formed by two ultrasonic beams and simultaneously receiving two reflected wave beams at predetermined intervals (d) by each of the two ultrasonic beams, A preliminary scan for receiving reflected wave beams (received beams 1a to 1d) at the same position as the reflected wave beams received in the main scan is executed.

  That is, by performing the preliminary can illustrated in FIG. 8, the receiving unit 12 simultaneously receives the reception beams 1a and 1b at the same positions as the reception beams 2a and 2b by the first transmission / reception. Then, the reception unit 12 simultaneously receives the reception beams 1c and 1d at the same position as the reception beams 2c and 2d by the second transmission / reception by the ultrasonic beam that has moved the central axis by a predetermined interval (d) from the first central axis. Receive.

  As described above, the control unit 18 according to the first embodiment shifts the central axis of the ultrasonic beam at predetermined intervals during the preliminary scan for the reception beam that is simultaneously received by one transmission and reception during the main scan. , And receive them two times in multiple times. In other words, the control unit 18 according to the first embodiment shifts the reception beam at the same position as all received data received during the main scan, and shifts the central axis of the ultrasonic beam at predetermined intervals during the preliminary scan. However, it collects by receiving 2 each.

  As shown in FIGS. 7 and 8, the two reception beams received simultaneously in one transmission / reception in the preliminary scan are adjacent to the central axis of the ultrasonic beam. That is, the reception sensitivity of the two reception beams received simultaneously in one transmission / reception in the preliminary scan is highly uniform because the position of the reception beam is set at a position where the transmission sound field is substantially uniform.

  The control unit 18 according to the first embodiment executes the preliminary scan from the operator via the input device 3 together with the imaging conditions (the predetermined interval, the number of transmission beams, the number of simultaneous reception beams, etc.) of the parallel simultaneous reception method. When the request is accepted, a preliminary scan is executed before the main scan. However, the present embodiment is not limited to the case where the preliminary scan is executed when the preliminary scan execution request is received. For example, when the imaging condition of the parallel simultaneous reception method is received, the standby scan is automatically performed. It may be a case where a scan is executed.

  Here, sensitivity correction of the correction unit 13c, which will be described later, is executed in response to a request for execution of preliminary scanning. Therefore, hereinafter, “preliminary scan execution request” may be referred to as “correction request”.

  The detection unit 13a illustrated in FIG. 1 detects the reception sensitivity of the reflected wave beam received by the main scan. Furthermore, the detection unit 13a detects the reception sensitivity of the reflected wave beam received by the preliminary scan. Here, the reflected wave beam received by the main scan is defined as a “first reflected wave beam”, and the reflected wave beam received by the preliminary scan is defined as a “second reflected wave beam”. If such a definition is used, the “second reflected wave beam” for which the detection unit 13a detects the reception sensitivity is a reflected wave beam corresponding to the position of the “first reflected wave beam”. Specifically, the “second reflected wave beam” is a reflected wave beam synthesized by beam synthesis, and is a reflected wave beam whose reception position corresponds to the “first reflected wave beam”. First, the detection unit 13a detects the reception sensitivity of each reflected wave beam (each received beam and the second reflected wave beam) received by the preliminary scan. Specifically, the detection unit 13a detects the reception sensitivity of the reflected wave data generated by the reception unit 12 from each reflected wave beam of the preliminary scan. More specifically, the detection unit 13a detects the reception sensitivity of the reflected wave data of the preliminary scan along the depth direction. For example, the detection unit 13a detects the amplitude value for each depth of the reflected wave data of the preliminary scan and the luminance value for each depth as the reception sensitivity along the depth direction.

  Then, the detection unit 13a stores the reception sensitivity of the reflected wave data corresponding to the reception sensitivity of each reception beam received in the preliminary scan in the detection data storage unit 13b in association with the position information in the scanning direction. The detected data storage unit 13b is, for example, a semiconductor memory element.

  The control unit 18 starts the main scan after the preliminary scan is completed. The detection unit 13a further detects the reception sensitivity of each reflected wave beam received by the main scan. That is, the reception beam (first reflected wave beam) received by the ultrasonic probe 1 in the main scan is reflected wave data in the receiving unit 12, and the detection unit 13a receives each reflected wave beam received in the main scan. The reception sensitivity of the reflected wave data corresponding to the reception sensitivity is detected. Specifically, the detection unit 13a detects the reception sensitivity of the reflected wave data of the main scan along the depth direction. For example, the detection unit 13a detects the amplitude value for each depth and the luminance value for each depth of the reflected wave data of the main scan as the reception sensitivity along the depth direction.

  Then, the correction unit 13c shown in FIG. 1 compares the reception sensitivity of the first reflected wave beam with the reception sensitivity of the second reflected wave beam, thereby receiving each reflected wave beam received in the main scan. Perform sensitivity correction to increase or decrease sensitivity. In other words, the correction unit 13c compares the reception sensitivities of the reflected wave beams at the same position between the preliminary scan and the main scan, thereby increasing or decreasing the sensitivity of each reflected wave beam received in the main scan. To do. That is, the correction unit 13c acquires the reception sensitivity of the main scan from the detection unit 13a, acquires the reception sensitivity of the preliminary scan from the detection data storage unit 13b, and sets the reception beam at the same position between the preliminary scan and the main scan. Compare the reception sensitivity of the corresponding reflected wave data. Specifically, the correction unit 13c compares the reception sensitivity of the reflected wave data at the same position between the preliminary scan and the main scan. More specifically, the correction unit 13c compares the reception sensitivity of the reflected wave data at the same position between the preliminary scan and the main scan for each depth. FIG. 9 is a diagram for explaining the correction unit according to the first embodiment.

  For example, as shown in FIG. 9, the correction unit 13c compares the reception sensitivity of the reception beam 1a and the reception sensitivity of the reception beam 2a along the depth direction, and corrects the reception sensitivity of the reception beam 2a. That is, the correction unit 13c compares the reception sensitivity of the reflected wave data generated from the reception beam 1a and the reception sensitivity of the reflected wave data generated from the reception beam 2a along the depth direction, and compares the reception sensitivity of the reception beam 2a. Correct the reception sensitivity. Further, as shown in FIG. 9, the correction unit 13c compares the reception sensitivity of the reception beam 1b with the reception sensitivity of the reception beam 2b along the depth direction, and corrects the reception sensitivity of the reception beam 2a. That is, the correction unit 13c compares the reception sensitivity of the reflected wave data generated from the reception beam 1b with the reception sensitivity of the reflected wave data generated from the reception beam 2b along the depth direction, and compares the reception sensitivity of the reception beam 2b. Correct the reception sensitivity.

  Hereinafter, the process of the correction unit 13c will be described in detail using mathematical expressions. First, the reception sensitivity for each depth of the reception beam 1a in the preliminary scan is defined as “S (1a (t))” below, and the reception sensitivity for each depth of the reception beam 1b in the preliminary scan is expressed as “S (1b ( t)) ”. Further, the reception sensitivity for each depth of the reception beam 2a in the main scan is “S (2a (t))” below, and the reception sensitivity for each depth of the reception beam 2b in the main scan is “S (2b (t))”. ) ”. In the above, “time: t” is used as a value indicating the depth.

  Here, as described above, the reception beams 1a and 2a are reception beams at the same position, and the reception beams 1b and 2b are reception beams at the same position. In addition, the reception sensitivity of the reception beam of the preliminary scan is a target value of the reception sensitivity of the reception beam at the same position received in the main scan.

  Therefore, the correction unit 13c sets the reception sensitivity ratio “Sr (2a (t))” to “S (2a (t))” so that “S (2a (t))” becomes “S (1a (t))”. ) ". “Sr (2a (t))” is expressed by the following equation (1).

      Sr (2a (t)) = S (1a (t)) / S (2a (t)) (1)

  The correction unit 13c multiplies the reception beam 2a by a gain “G (2a (t))” expressed by the following equation (2).

      G (2a (t)) = Sr (2a (t)) = S (1a (t)) / S (2a (t)) (2)

  Similarly, the correction unit 13c multiplies the reception beam 2a by a gain “G (2b (t))” expressed by the following equation (3).

      G (2b (t)) = Sr (2b (t)) = S (1b (t)) / S (2b (t)) (3)

  With the sensitivity correction described above, the reception sensitivity of each reception beam in the main scan that is non-uniform in the scanning direction is gain-corrected to the same level as the reception sensitivity of each reception beam in the preliminary scan that is uniform in the scanning direction. The Rukoto. Also in the depth direction, the reception sensitivity of each reception beam in the main scan is gain-corrected to the same level as the reception sensitivity of each reception beam in the preliminary scan.

  Then, the image generation unit 16 generates an ultrasonic image using each reflected wave beam of the main scan whose sensitivity is corrected by the correction unit 13c. That is, the image generation unit 16 generates an ultrasonic image using data generated by the B-mode processing unit 14 and the Doppler processing unit 15 using each reflected wave data of the main scan whose sensitivity is corrected by the correction unit 13c. In the present embodiment, the image generation unit 16 generates a two-dimensional ultrasonic image.

  Note that the control unit 18 continuously performs the main scan of the region of interest set as the imaging region until an end request is received from the operator via the input device 3. The detection unit 13a performs sensitivity correction using the reception sensitivity of the reception beam (reflected wave data) of the preliminary scan every time the main scan for one frame is completed. Then, the image generation unit 16 sequentially generates ultrasonic images along the time series by using the reflected wave data for one frame whose sensitivity has been corrected sequentially along the time series.

  In the above description, the case where the detection unit 13a performs the reception sensitivity detection processing of the preliminary scan and the main scan using the output data of the reception unit 12 has been described. However, the data for which the detection unit 13a executes the reception sensitivity detection process may be output data of the B mode processing unit 14, for example. In such a case, the reception data processing unit 13 is arranged at the subsequent stage of the B mode processing unit 14.

  Next, processing of the ultrasonic diagnostic apparatus according to the first embodiment will be described with reference to FIG. FIG. 10 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment.

  As shown in FIG. 10, the ultrasonic diagnostic apparatus according to the first embodiment determines whether or not the input apparatus 3 has received an imaging request and a correction request based on the parallel simultaneous reception method from the operator (step 101). That is, the ultrasonic diagnostic apparatus determines whether an imaging request including an imaging condition based on the parallel simultaneous reception method and an execution request for a preliminary scan have been received.

  Here, when the imaging request and the correction request by the parallel simultaneous reception method are not accepted (No in step S101), the ultrasonic diagnostic apparatus enters a standby state. On the other hand, when the imaging request and the correction request by the parallel simultaneous reception method are received (Yes at Step S101), the control unit 18 performs a preliminary scan (Step S102). Then, the detection unit 13a detects the reception sensitivity of the reflected wave data generated by the reception unit 12 using the reception beam of the preliminary scan (Step S103), and stores the detection result in the detection data storage unit 13b (Step S104). .

  Then, the control unit 18 starts the main scan (step S105), and determines whether or not reflected wave data for one frame is generated from the reception beam of the main scan by the reception unit 12 (step S106). Here, when the reflected wave data for one frame has not been generated (No at Step S106), the ultrasonic diagnostic apparatus enters a standby state.

  On the other hand, when the reflected wave data for one frame is generated (Yes at Step S106), the detection unit 13a detects the reception sensitivity of the reflected wave data of the main scan (Step S107). Then, the correcting unit 13c calculates the gain by comparing the reception sensitivity of the reflected wave data at the same position between the preliminary scan and the main scan, and executes the sensitivity correction of the reflected wave data (step S108).

  Then, the image generation unit 16 generates an ultrasonic image using the reflected wave data whose sensitivity has been corrected (step S109). Note that the ultrasonic image generated in step S109 is displayed on the monitor 2 under the control of the control unit 18, for example.

  Then, the control unit 18 determines whether or not a request for ending the main scan has been received (step S110). If the main scan end request is not accepted (No at Step S110), the control unit 18 returns to Step S106 and determines whether or not one frame of reflected wave data has been newly generated.

  On the other hand, when an end request for the main scan is received (Yes at Step S110), the ultrasound diagnostic apparatus ends the process.

  As described above, in the first embodiment, the control unit 18 sets the received beam at the same position as all received data received during the main scan, and sets the center axis of the ultrasonic beam at a predetermined interval during the preliminary scan. Collecting data by receiving them two by one while shifting each time. The detection unit 13a detects the reception sensitivity of the reflected wave data generated from the reception beam at the time of the preliminary scan and the reflected wave data generated from the reception beam at the time of the main scan. The correction unit 13c corrects the reception sensitivity of the reflected wave data group every time a reflected wave data group for one frame is generated during the main scan. That is, the correction unit 13c compares the reception sensitivity of the reflected wave data at the same position between the preliminary scan and the main scan for each depth, and determines the reception sensitivity of each reflected wave beam received in the main scan. Perform sensitivity correction to increase or decrease. Then, the image generation unit 16 generates an ultrasonic image using the reflected wave data whose sensitivity has been corrected. In the above description, the case where sensitivity correction is performed by performing reception sensitivity comparison processing every time a reflection data group for one frame is generated has been described. However, the present embodiment may be a case in which sensitivity correction is performed by performing reception sensitivity comparison processing when one beam of combined beams is combined and one beam of reflected wave data is obtained.

  The reception sensitivity of the two reception beams received simultaneously in one transmission / reception in the preliminary scan is highly uniform because the position of the reception beam is set at a position where the transmission sound field is substantially uniform. In other words, the reception sensitivity of the reflected wave data during the preliminary scan is highly uniform, and the reflected wave data of the main scan in which the reception sensitivity is corrected in accordance with the reception sensitivity of the reflected wave data during the preliminary scan has uneven sensitivity. It has been resolved. In addition, since the reception sensitivity of the main scan increases the weak reception sensitivity to the target value of gain in the preliminary scan, the image quality of the ultrasonic image is high. Therefore, the ultrasonic image generated in the present embodiment does not generate striped pattern artifacts and has high image quality. Further, the sensitivity correction process executed using the preliminary scan is a process based on an actual measurement value reflecting the biological condition of the subject P to be imaged. In addition, after the preliminary scan is performed once, the normal main scan is performed and an ultrasonic image is generated, so that the frame rate does not decrease. As a result, in the first embodiment, an ultrasonic image with high time resolution can be generated with high image quality using the parallel simultaneous reception method.

  In the first embodiment, the execution of the preliminary scan, that is, the execution of the sensitivity correction can be designated by the operator, so that the image capturing by the parallel simultaneous reception method with the sensitivity correction is executed according to the operator's request. can do.

(Second Embodiment)
In the second embodiment, a case will be described in which the sensitivity correction process is stopped according to the reception sensitivity of the preliminary scan.

  The ultrasonic diagnostic apparatus according to the second embodiment is configured similarly to the ultrasonic diagnostic apparatus according to the first embodiment described with reference to FIG. However, the control unit 18 according to the second embodiment further performs the following control process. FIG. 11 is a diagram for explaining the second embodiment.

  In the sensitivity correction processing described in the first embodiment, an appropriate gain is automatically set to the main scan automatically using data at the time of the preliminary scan detected in accordance with the biological condition of the imaging region of the subject P to be actually imaged. This is given to the reflected wave data at the time. That is, the reception sensitivity correction is an appropriate process if a preliminary scan is performed in a state where the ultrasonic probe 1 is applied to the subject P. However, for example, as shown in FIG. 11A, when the ultrasonic probe 1 is separated from the subject P and is left in the air, the reflected wave beam is not received, so that the reception sensitivity is significantly reduced. . The gain calculated using the greatly reduced reception sensitivity is greatly increased, and white noise (White Noise) is generated in the ultrasonic image generated using the reflected wave data whose sensitivity is corrected by the greatly increased gain. ) Stripe unevenness occurs. Further, depending on an operator who refers to an ultrasonic image in which white noise has occurred, it may be determined that a failure has occurred in the ultrasonic diagnostic apparatus. In addition, white noise is generated even when the ultrasonic probe 1 is left in the air during the main scan.

  Therefore, as shown in FIG. 11B, the control unit 18 according to the second embodiment, when the reception sensitivity of the preliminary scan is smaller than the predetermined lower limit threshold, or the reception sensitivity of the main scan is the predetermined lower limit. If it is smaller than the threshold, the sensitivity correction process of the correction unit 13c is stopped. For example, the lower limit threshold is set in advance based on the condition of leaving in the air where the received signal is low. Alternatively, the lower limit threshold can be arbitrarily changed by the operator based on the condition of leaving in the air where the received signal is low.

  Next, processing of the ultrasonic diagnostic apparatus according to the second embodiment will be described with reference to FIGS. 12-1 and 12-2. FIG. 12A is a flowchart for explaining a correction control process during a preliminary scan of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 12B is a flowchart for explaining the correction control process during the main scan of the ultrasonic diagnostic apparatus according to the second embodiment.

  As illustrated in FIG. 12A, the ultrasonic diagnostic apparatus according to the second embodiment determines whether or not the input apparatus 3 has received an imaging request and a correction request based on the parallel simultaneous reception method from the operator (step 201). ). Here, when the imaging request and the correction request by the parallel simultaneous reception method are not received (No in step S201), the ultrasonic diagnostic apparatus is in a standby state.

  On the other hand, when the imaging request and the correction request by the parallel simultaneous reception method are received (Yes in Step S201), the control unit 18 performs a preliminary scan (Step S202). Then, the detection unit 13a detects the reception sensitivity of the reflected wave data generated by the reception unit 12 using the reception beam of the preliminary scan (Step S203), and stores the detection result in the detection data storage unit 13b (Step S104). .

  And the control part 18 determines whether the receiving sensitivity of reflected wave data is smaller than a lower limit threshold value (step S205). Here, when the reception sensitivity of the reflected wave data is equal to or higher than the lower limit threshold (No at Step S205), the control unit 18 executes the main scan with correction (Step S206), and ends the correction control process at the time of the preliminary scan. .

  On the other hand, when the reception sensitivity of the reflected wave data is smaller than the lower limit threshold (Yes at Step S205), the control unit 18 executes the main scan without correction (Step S207), and ends the correction control process at the time of the preliminary scan. That is, the main scan without correction is the processing of “Step S106, Steps S109 and S110 executed using the reflected wave data without sensitivity correction” shown in FIG.

  Then, as illustrated in FIG. 12B, during the main scan, the ultrasonic diagnostic apparatus according to the second embodiment is controlled by the control unit 18 that has determined that the main scan with correction is executed in step S201. The main scan with correction is started (step S301), and it is determined whether or not the reflected wave data for one frame is generated from the reception beam of the main scan by the receiving unit 12 (step S302). Here, when the reflected wave data for one frame is not generated (No at Step S302), the ultrasonic diagnostic apparatus is in a standby state.

  On the other hand, when the reflected wave data for one frame is generated (Yes at Step S302), the detection unit 13a detects the reception sensitivity of the reflected wave data of the main scan (Step S303). Then, the control unit 18 determines whether or not the reception sensitivity of the reflected wave data is smaller than the lower limit threshold (step S304). Here, when the reception sensitivity of the reflected wave data is smaller (Yes at Step S304), the control unit 18 determines “no correction”, and the image generation unit 16 obtains an ultrasonic image from the reflected wave data without sensitivity correction. Generate (step S307).

  On the other hand, when the reception sensitivity of the reflected wave data is equal to or higher than the lower limit threshold (No in step S304), the control unit 18 determines that “correction is present”, and the correction unit 13c has the same position between the preliminary scan and the main scan. The gain is calculated by comparing the reception sensitivity of the reflected wave data, and the sensitivity correction of the reflected wave data is executed (step S305). Then, the image generation unit 16 generates an ultrasonic image using the reflected wave data after the sensitivity correction (step S306).

  Then, after step S306 or step S307, the control unit 18 determines whether or not a request for ending the main scan has been received (step S308). If the main scan end request is not accepted (No at Step S308), the control unit 18 returns to Step S302 and determines whether or not one frame of reflected wave data has been newly generated.

  On the other hand, when an end request for the main scan is received (Yes at step S308), the ultrasound diagnostic apparatus ends the process.

  In the example illustrated in FIG. 12B, the case where “correction” or “no correction” is determined for each frame in the main scan has been described. However, in the second embodiment, in the main scan, In this case, the frames after the determination of “no correction” may be all “no correction”. In the above description, the case where the sensitivity correction is performed by performing the reception sensitivity comparison process every time the reflection data group for one frame is generated has been described. However, the present embodiment may be a case in which sensitivity correction is performed by performing reception sensitivity comparison processing when one beam of combined beams is combined and one beam of reflected wave data is obtained.

  As described above, in the second embodiment, it is possible to avoid the occurrence of white noise by leaving the ultrasonic probe 1 in the air during the preliminary scan or the main scan.

(Third embodiment)
In the third embodiment, a case where sensitivity correction processing is limited will be described.

  The ultrasonic diagnostic apparatus according to the third embodiment is configured similarly to the ultrasonic diagnostic apparatus according to the first embodiment described with reference to FIG. However, the control unit 18 according to the third embodiment further performs the following control process. FIG. 13 is a diagram for explaining the third embodiment.

  As described above, the sensitivity correction processing described in the first embodiment is automatically and appropriately performed using the data at the time of the preliminary scan detected in accordance with the biological condition of the imaging region of the subject P that is actually imaged. A large gain is given to the reflected wave data during the main scan. However, even when the ultrasonic probe 1 is appropriately applied to the subject P, the gain value for sensitivity correction may increase depending on the biological conditions. As described above, fringe unevenness due to white noise occurs in an ultrasonic image generated using reflected wave data whose sensitivity has been corrected using such gain.

  Therefore, the control unit 18 according to the third embodiment causes the increase rate of the sensitivity correction executed by the correction unit 13c to be equal to or less than a predetermined upper limit threshold value. That is, as shown in FIG. 13A, the control unit 18, for example, receives the reception sensitivity ratio “Sr (2a (t)) = S (1a (t)) / S (2a (t)) of the reception beam 2a. ) ”Is equal to or smaller than the upper threshold“ Gmax ”,“ Sr (2a (t)) ”is used as it is as the gain“ G (2a (t)) ”.

  On the other hand, as shown in FIG. 13B, the control unit 18 receives, for example, the reception sensitivity ratio “Sr (2a (t)) = S (1a (t)) / S (2a (t)) of the reception beam 2a. ) ”Is a value greater than the upper threshold“ Gmax ”,“ Gmax ”is used as the gain“ G (2a (t)) ”. For example, the upper limit threshold is set in advance based on the conditions under which white noise occurs. Alternatively, the upper threshold value can be arbitrarily changed by the author.

  Note that the process of the ultrasonic diagnostic apparatus according to the third embodiment is the same as that of the first embodiment except that the gain value used in the sensitivity correction process is limited to the upper threshold or lower in step S108 shown in FIG. Since it is the same as the processing of the ultrasonic diagnostic apparatus, description thereof is omitted. Note that the third embodiment is applicable even when the process using the lower threshold described in the second embodiment is executed in combination with the process using the upper threshold.

  As described above, in the third embodiment, it is possible to avoid the occurrence of white noise by applying too much gain.

  In the first to third embodiments described above, a case where a two-dimensional ultrasonic image is captured by a two-dimensional main scan has been described. However, the first to third embodiments described above are applicable even when a three-dimensional ultrasonic image is captured by a three-dimensional main scan. 14 and 15 are diagrams for explaining the preliminary scan in the three-dimensional scan.

  FIG. 14A shows a scan form by the ultrasonic probe 1 which is a mechanical scan probe. The mechanical scan probe scans the subject P in three dimensions by swinging a plurality of ultrasonic transducers that scan the subject P in two dimensions at a predetermined angle (swing angle).

  That is, when the ultrasonic probe 1 is a mechanical scan probe, the reception beam is collected over a plurality of scanning planes. Therefore, when the ultrasonic probe 1 is a mechanical scan probe, as in the first embodiment, as shown in FIG. 14B, the preliminary scan is performed along the central axis of the ultrasonic beam along the scanning direction. This may be executed by simultaneously receiving two reception beams adjacent to the.

  On the other hand, when the ultrasonic probe 1 is a two-dimensional ultrasonic probe capable of ultrasonically scanning the subject P in three dimensions by arranging a plurality of ultrasonic transducers in a matrix, the following A preliminary scan is performed. That is, when the main scan is a three-dimensional scan, the control unit 18 has four reflected waves that are symmetric (point symmetric) with respect to the central axis of each ultrasonic beam in the preliminary scan, as shown in FIG. The transmitter 11 and the receiver 12 are controlled so as to receive the beams simultaneously.

  By performing the preliminary scan shown in FIG. 15, even when the parallel simultaneous reception method is executed using a two-dimensional ultrasonic probe, it is possible to correct the reception sensitivity and generate a high-quality ultrasonic image. .

  Note that the image generation control method described in the above embodiment can be realized by executing an image generation control program prepared in advance on a computer such as a personal computer or a workstation. This program can be distributed via a network such as the Internet. The program can also be executed by being recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, and a DVD and being read from the recording medium by the computer.

  As described above, according to the first to third embodiments, an ultrasonic image with high time resolution can be generated with high image quality using the parallel simultaneous reception method.

  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 scope 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 part 12 Reception part 13 Reception data processing part 13a Detection part 13b Detection data storage part 13c Correction part 14 B mode processing part 15 Doppler processing part 16 Image generation part 17 Image memory 18 Control unit 19 Internal storage unit

Claims (8)

A transmission / reception unit that transmits an ultrasonic beam and performs ultrasonic scanning by receiving a reflected wave beam of the transmitted ultrasonic beam;
Before executing the main scan for capturing an ultrasonic image by the parallel simultaneous reception method, the ultrasonic beam is transmitted, and at least two of the reflected wave beams of the ultrasonic beam are simultaneously received. A control unit for controlling the transmission / reception unit so as to perform a preliminary scan for receiving a reflected wave beam at a position corresponding to the reflected wave beam received in the main scanning;
The receiving sensitivity of the first reflected wave beam received by the main scanning is detected, and the receiving sensitivity of the second reflected wave beam corresponding to the position of the first reflected wave beam received by the preliminary scanning is further detected. A detection unit for detecting
By comparing the reception sensitivity of the first reflected wave beam with the reception sensitivity of the second reflected wave beam, sensitivity correction is performed to increase or decrease the reception sensitivity of each reflected wave beam received in the main scan. A correction unit, and an image generation unit that generates an ultrasonic image using each reflected wave beam of the main scan, the sensitivity of which is corrected by the correction unit;
An ultrasonic diagnostic apparatus comprising:   The controller is configured to cause each region formed by a plurality of reflected wave beams at predetermined intervals to be simultaneously received by a plurality of ultrasonic beams sequentially transmitted along the scanning direction in the main scanning along the scanning direction. The ultrasonic diagnostic apparatus according to claim 1, wherein the preliminary scanning is executed by controlling the transmission / reception unit so as to perform scanning with a plurality of ultrasonic beams separated by the predetermined interval.   When the main scan is a two-dimensional scan, the control unit causes the transmitter / receiver to simultaneously receive two reflected wave beams that are symmetric with respect to the central axis of each ultrasonic beam in the preliminary scan. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is controlled.   When the main scan is a three-dimensional scan, the control unit causes the transmitter / receiver to simultaneously receive four reflected wave beams that are symmetrical with respect to the central axis of each ultrasonic beam in the preliminary scan. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is controlled.   The super control unit according to claim 1, wherein the control unit causes the prescan to be executed when an execution request for the prescan is received from an operator via the input unit. Ultrasonic diagnostic equipment.   The control unit stops the sensitivity correction process of the correction unit when the reception sensitivity of the preliminary scanning is smaller than a predetermined lower threshold value or when the reception sensitivity of the main scanning is smaller than a predetermined lower threshold value. The ultrasonic diagnostic apparatus according to any one of claims 1 to 5.   The ultrasonic diagnostic apparatus according to claim 1, wherein the control unit causes an increase rate of sensitivity correction executed by the correction unit to be a predetermined upper limit threshold value or less. The main scanning for capturing an ultrasonic image by the parallel simultaneous reception method is performed on a transmission / reception unit that transmits an ultrasonic beam and receives a reflected wave beam of the transmitted ultrasonic beam to perform ultrasonic scanning. Before executing, the ultrasonic beam is transmitted, and at least two reflected wave beams among the reflected wave beams of the ultrasonic beam are received at the same time, so that the reflected wave beam received in the main scanning is handled. A control procedure for controlling to perform a pre-scan to receive a reflected beam of position;
The receiving sensitivity of the first reflected wave beam received by the main scanning is detected, and the receiving sensitivity of the second reflected wave beam corresponding to the position of the first reflected wave beam received by the preliminary scanning is further detected. Detection procedure to detect,
By comparing the reception sensitivity of the first reflected wave beam with the reception sensitivity of the second reflected wave beam, sensitivity correction is performed to increase or decrease the reception sensitivity of each reflected wave beam received in the main scan. A correction procedure; and an image generation procedure for generating an ultrasonic image using each reflected wave beam of the main scan, the sensitivity of which has been corrected by the correction procedure;
An image generation control program for causing a computer to execute.

Images