JP2012161560A - Ultrasound diagnostic apparatus and ultrasound image producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic apparatus and an ultrasound image producing method capable of efficiently obtaining data for producing a B mode image and data for measuring the sound speed to achieve production of both a B mode image and a sound speed map.SOLUTION: A plurality of lattice points are set on sound rays S3-S5 passing inside a region of interest R and in the region of interest R, points F located at a given depth L1 are set on sound rays S1, S2, S6, and S7 passing outside the region of interest R, lattice points E2 located at the deepest depth have a depth closest to the given depth L1 among the lattice points set inside the region of interest R, these lattice points serve as transmission focuses for both the production of the B mode image and the measurement of the sound speed, and the other lattice points E1 serve as transmission focuses used exclusively for the measurement of the sound speed. A B mode image signal is produced based on the reception data obtained by forming the transmission focus at the points F outside the region of interest R and the lattice points E2 inside the region of interest R. The reception data obtained by forming the transmission focuses at the lattice points E1, E2 in the region of interest R is used to calculate local sound speeds, and a sound speed map is produced.

Description

  The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic image generation method, and more particularly, to generate both a B-mode image and a sound velocity map in a region of interest by transmitting and receiving ultrasonic waves from a transducer array of an ultrasonic probe. The present invention relates to an ultrasonic diagnostic apparatus.

  Conventionally, in the medical field, an ultrasonic diagnostic apparatus using an ultrasonic image has been put into practical use. In general, this type of ultrasonic diagnostic apparatus has an ultrasonic probe with a built-in transducer array and an apparatus main body connected to the ultrasonic probe. An ultrasonic image is generated by transmitting a sound beam, receiving an ultrasonic echo from the subject with an ultrasonic probe, and electrically processing the received signal with the apparatus main body.

In recent years, in order to more accurately diagnose a diagnostic site in a subject, the speed of sound at the diagnostic site has been measured.
For example, in Patent Document 1, a plurality of lattice points are set around a diagnostic region, and a local sound velocity value is calculated based on reception data obtained by transmitting and receiving an ultrasonic beam to each lattice point. An ultrasonic diagnostic apparatus has been proposed.

JP 2010-99452 A

With the apparatus of Patent Document 1, a local sound velocity value at a diagnostic site can be obtained by transmitting and receiving an ultrasonic beam from an ultrasonic probe into a subject. For example, information on a local sound velocity value is superimposed on a B-mode image. Can be displayed.
By the way, when a diagnosis is performed on a specific region in the subject, it is effective to display a sound velocity map indicating the distribution of local sound velocity values at each point in the region in addition to the B-mode image. .
However, if both the generation of the B-mode image and the generation of the sound velocity map of the diagnostic region are to be performed, the ultrasonic beam must be transmitted and received many times, and the data for generating the B-mode image and the sound velocity measurement For this reason, it takes a lot of time and labor to acquire data.

  The present invention has been made to solve such a conventional problem, and efficiently obtains B-mode image generation data and sound speed measurement data to generate a B-mode image and a sound speed map. It is an object to provide an ultrasonic diagnostic apparatus and an ultrasonic image generation method capable of performing both of the above.

  An ultrasonic diagnostic apparatus according to the present invention transmits an ultrasonic beam from a transducer array of an ultrasonic probe toward a subject and receives an ultrasonic echo from the subject based on a drive signal supplied from a transmission circuit. An ultrasonic diagnostic apparatus that generates an ultrasonic image based on reception data obtained by processing a reception signal output from a transducer array of an ultrasonic probe using a reception circuit. A region of interest setting unit for setting, a plurality of lattice points are set in the region of interest on a sound ray passing through the inside of the region of interest set by the region of interest setting unit, and a transmission focal point is formed at the plurality of lattice points. In this way, reception data for sound velocity measurement is acquired by transmitting and receiving ultrasonic beams, respectively, and at the same time, a transmission focal point is formed at a predetermined depth with respect to a sound ray passing outside the region of interest. A control unit that controls the transmission circuit and the reception circuit so as to acquire first reception data for generating a B-mode image by performing transmission and reception of a sound beam, and a sound speed in the region of interest based on the reception data for sound speed measurement A sound velocity map generator for generating a map, and for a sound ray passing through the inside of the region of interest, a transmission focal point is formed at a lattice point having a depth closest to a predetermined depth among a plurality of lattice points, and an ultrasonic beam The reception data for sound velocity measurement acquired by performing transmission / reception is used as second reception data for B-mode image generation, and a B-mode image is generated based on the first and second reception data for B-mode image generation And an image generation unit.

The control unit preferably sets the predetermined depth to be equal to any one of the plurality of grid points. In this case, the control unit can set the predetermined depth to be equal to the depth of the lattice point located at the center in the depth direction of the region of interest among the plurality of lattice points.
The control unit can also set a plurality of predetermined depths for sound rays that pass outside the region of interest. Further, in this case, the control unit can set two predetermined depths equal to the depth of the lattice point located at the shallowest portion and the lattice point located at the deepest portion among the plurality of lattice points.

  In the ultrasonic image generation method according to the present invention, an ultrasonic beam is transmitted from a transducer array of an ultrasonic probe toward a subject based on a drive signal supplied from a transmission circuit, and an ultrasonic echo by the subject is transmitted. An ultrasonic image generation method for generating an ultrasonic image based on reception data obtained by processing a reception signal output from a transducer array of a received ultrasonic probe by a reception circuit, and in the imaging region Set the region and set multiple lattice points on the sound line passing through the inside of the region of interest and within the region of interest, and form the transmission focal point at the plurality of lattice points to transmit and receive the ultrasonic beam, respectively. And receiving a sound data, generating a sound speed map in the region of interest based on the sound speed measurement received data, and at least one predetermined depth for a sound ray passing outside the region of interest. The first reception data for generating the B-mode image is acquired by forming a transmission focal point and transmitting / receiving an ultrasonic beam, and for a sound ray passing through the inside of the region of interest, a predetermined one of a plurality of lattice points is obtained. The reception data for sound velocity measurement obtained by forming a transmission focal point at a lattice point having the depth closest to the depth of the image and transmitting and receiving an ultrasonic beam is used as second reception data for B-mode image generation, and B This is a method for generating a B-mode image based on first and second received data for generating a mode image.

  According to the present invention, the first reception data for generating the B-mode image is obtained by transmitting and receiving the ultrasonic beam by forming a transmission focal point at a predetermined depth with respect to the sound ray passing outside the region of interest, For a sound ray passing through the inside of the region of interest, a transmission focal point is formed at a lattice point having a depth closest to a predetermined depth among a plurality of lattice points set for sound velocity measurement, and an ultrasonic beam is transmitted and received. Since the received data for measuring the sound speed is used as the second received data for generating the B-mode image, the data for generating the B-mode image and the data for measuring the sound speed can be efficiently acquired to obtain the B-mode image. Both generation and sound speed map generation can be performed.

1 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention. 3 is a diagram schematically illustrating the principle of sound speed calculation in Embodiment 1. FIG. 6 is a diagram illustrating a transmission focus for generating a B-mode image and a transmission focus for measuring a sound velocity in the first embodiment. FIG. FIG. 10 is a diagram showing a transmission focus for B-mode image generation and a transmission focus for sound speed measurement in a modification of the first embodiment. FIG. 10 is a diagram illustrating a transmission focus for B-mode image generation and a transmission focus for sound velocity measurement in the second embodiment. It is a figure which shows the transmission focus for B mode image generation in the modification of Embodiment 2, and the transmission focus for sound speed measurement. FIG. 10 is a diagram illustrating a transmission focus for B-mode image generation and a transmission focus for sound velocity measurement in the third embodiment. FIG. 10 is a diagram showing a transmission focus for B-mode image generation and a transmission focus for sound velocity measurement in the fourth embodiment. FIG. 10 is a diagram showing a transmission focus for B-mode image generation and a transmission focus for sound velocity measurement in a modification of the fourth embodiment. FIG. 16 is a diagram showing a transmission focus for B-mode image generation and a transmission focus for sound velocity measurement in another modification of the fourth embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1
FIG. 1 shows the configuration of an ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention. The ultrasonic diagnostic apparatus includes a transducer array 1 to which a transmission circuit 2 and a reception circuit 3 are connected. A signal processing unit 4, a DSC (Digital Scan Converter) 5, and an image processing unit 6 are sequentially connected to the receiving circuit 3, and a display unit 8 is connected to the image processing unit 6 via a display control unit 7. An image memory 9 is connected.
Further, a cine memory 10 and a sound velocity map generator 11 are respectively connected to the receiver circuit 3, and a control unit is connected to the transmitter circuit 2, receiver circuit 3, signal processor 4, DSC 5, display controller 7, cine memory 10 and sound velocity map generator 11. 12 is connected. Furthermore, an operation unit 13 and a storage unit 14 are connected to the control unit 12.

  The transducer array 1 has a plurality of ultrasonic transducers arranged one-dimensionally or two-dimensionally. Each of these ultrasonic transducers transmits an ultrasonic wave according to the drive signal supplied from the transmission circuit 2 and receives an ultrasonic echo from the subject and outputs a received signal. Each ultrasonic transducer is, for example, a piezoelectric ceramic represented by PZT (lead zirconate titanate), a polymer piezoelectric element represented by PVDF (polyvinylidene fluoride), or PMN-PT (magnesium niobate / lead titanate). It is constituted by a vibrator in which electrodes are formed on both ends of a piezoelectric body made of a piezoelectric single crystal represented by a solid solution).

  When a pulsed or continuous wave voltage is applied to the electrodes of such a vibrator, the piezoelectric body expands and contracts, and pulsed or continuous wave ultrasonic waves are generated from the respective vibrators, and the synthesis of those ultrasonic waves. As a result, an ultrasonic beam is formed. In addition, each transducer generates an electric signal by expanding and contracting by receiving propagating ultrasonic waves, and these electric signals are output as ultrasonic reception signals.

  The transmission circuit 2 includes, for example, a plurality of pulsars, and an ultrasonic wave transmitted from the plurality of ultrasonic transducers of the transducer array 1 based on a transmission delay pattern selected according to a control signal from the control unit 12. The delay amount of each drive signal is adjusted so that the sound wave forms an ultrasonic beam, and then supplied to a plurality of ultrasonic transducers.

  The reception circuit 3 amplifies the reception signal transmitted from each ultrasonic transducer of the transducer array 1 and performs A / D conversion, and then, based on the reception delay pattern selected according to the control signal from the control unit 12. According to the set sound speed or distribution of sound speed, the reception focus process is performed by adding each received signal with a delay. By this reception focus processing, reception data (sound ray signal) in which the focus of the ultrasonic echo is narrowed is generated.

The signal processing unit 4 corrects attenuation by distance according to the depth of the reflection position of the ultrasonic wave on the reception data generated by the reception circuit 3, and then performs an envelope detection process so that the inside of the subject is detected. A B-mode image signal, which is tomographic image information related to the tissue of, is generated.
The DSC 5 converts (raster conversion) the B-mode image signal generated by the signal processing unit 4 into an image signal according to a normal television signal scanning method.
The image processing unit 6 performs various necessary image processing such as gradation processing on the B-mode image signal input from the DSC 5, and then outputs the B-mode image signal to the display control unit 7 or stores it in the image memory 9. Store.
These signal processing unit 4, DSC 5, image processing unit 6 and image memory 9 form an image generation unit 15 of the present invention.

The display control unit 7 causes the display unit 8 to display an ultrasound diagnostic image based on the B-mode image signal that has been subjected to image processing by the image processing unit 6.
The display unit 8 includes, for example, a display device such as an LCD, and displays an ultrasound diagnostic image under the control of the display control unit 7.

The cine memory 10 sequentially stores the reception data output from the reception circuit 3. Further, the cine memory 10 stores information related to the frame rate input from the control unit 12 (for example, parameters indicating the reflection position depth, the scanning line density, and the visual field width) in association with the received data.
The sound velocity map generation unit 11 calculates a local sound velocity value in the tissue in the subject to be diagnosed based on the received data stored in the cine memory 10 under the control of the control unit 12 and generates a sound velocity map. To do.
The control unit 12 controls each part of the ultrasonic diagnostic apparatus based on a command input from the operation unit 13 by the operator.

The operation unit 13 is for an operator to perform an input operation. The operation unit 13 constitutes a region of interest setting unit of the present invention, and can be formed from a keyboard, a mouse, a trackball, a touch panel, and the like.
The storage unit 14 stores an operation program and the like, and a recording medium such as a hard disk, a flexible disk, an MO, an MT, a RAM, a CD-ROM, and a DVD-ROM can be used.
The signal processing unit 4, the DSC 5, the image processing unit 6, the display control unit 7, and the sound speed map generation unit 11 are composed of a CPU and an operation program for causing the CPU to perform various processes. You may comprise with a circuit.

  The operator can select one of the following three display modes from the operation unit 13. That is, a mode in which a B-mode image is displayed alone, a mode in which a sound speed map is superimposed on a B-mode image (for example, a display in which color coding or luminance is changed according to a local sound speed value, or a point where local sound speed values are equal) Among the modes in which the B-mode image and the sound velocity map image are displayed side by side, display in a desired mode can be performed.

  When displaying a B-mode image, first, ultrasonic waves are transmitted from a plurality of ultrasonic transducers of the transducer array 1 in accordance with a drive signal supplied from the transmission circuit 2, and each ultrasonic echo received from a subject is received. A reception signal is output from the ultrasonic transducer to the reception circuit 3, and reception data is generated by the reception circuit 3. Further, a B-mode image signal is generated by the signal processing unit 4 to which the received data is input, and the B-mode image signal is raster-converted by the DSC 5 and various image processes are performed on the B-mode image signal by the image processing unit 6. After that, an ultrasonic diagnostic image is displayed on the display unit 8 by the display control unit 7 based on the B-mode image signal.

On the other hand, the calculation of the local sound velocity value can be performed, for example, by the method described in Japanese Patent Application Laid-Open No. 2010-99452 filed by the applicant of the present application.
As shown in FIG. 2A, this method focuses on a received wave Wx that reaches the transducer array 1 from a lattice point X that is a reflection point of the subject when an ultrasonic wave is transmitted into the subject. 2B, a plurality of lattice points A1, A2,... Are arranged at equal intervals at a position shallower than the lattice point X, that is, a position close to the transducer array 1, as shown in FIG. The combined wave Wsum of the received waves W1, W2,... Received from the plurality of grid points A1, A2,... Received from the point X is received from the grid point X according to Huygens' principle. This is a method of obtaining a local sound velocity value at the lattice point X by utilizing the fact that it matches the wave Wx.

  First, optimum sound speed values for all lattice points X, A1, A2,. Here, the optimum sound speed value means that, for each lattice point, an ultrasonic image is formed by performing a focus calculation based on the set sound speed and shooting, and the contrast and sharpness of the image are changed when the set sound speed is changed variously. Is the highest sound speed value. For example, as described in JP-A-8-317926, the optimum sound speed value can be determined based on the contrast of the image, the spatial frequency in the scanning direction, the variance, and the like.

Next, the waveform of the virtual received wave Wx emitted from the lattice point X is calculated using the optimum sound velocity value for the lattice point X.
Further, the hypothetical local sound velocity value V at the lattice point X is variously changed to calculate virtual composite waves Wsum of the received waves W1, W2,... From the lattice points A1, A2,. . At this time, it is assumed that the sound velocity in the region Rxa between the lattice point X and each lattice point A1, A2,... Is uniform and equal to the local sound velocity value V at the lattice point X. The time until the ultrasonic wave propagated from the lattice point X reaches the lattice points A1, A2,... Is XA1 / V, XA2 / V,. Here, XA1, XA2,... Are the distances between the lattice points A1, A2,. Therefore, a virtual composite wave Wsum can be obtained by synthesizing the reflected waves emitted from the lattice points A1, A2,... Delayed by times XA1 / V, XA2 / V,. .

Next, errors between the plurality of virtual synthesized waves Wsum calculated by variously changing the hypothetical local sound velocity value V at the lattice point X and the virtual received wave Wx from the lattice point X are respectively calculated. The hypothetical local sound velocity value V that minimizes the error is calculated and determined as the local sound velocity value at the lattice point X. Here, as a method of calculating an error between the virtual synthesized wave Wsum and the virtual received wave Wx from the lattice point X, a method of obtaining a cross-correlation with each other, a delay obtained from the synthesized wave Wsum on the received wave Wx is used. A method of performing phase matching addition by multiplying, a method of performing phase matching addition by multiplying the synthesized wave Wsum by a delay obtained from the reception wave Wx, and the like can be employed.
As described above, the local sound velocity value in the subject can be calculated with high accuracy based on the reception data generated by the reception circuit 3. Furthermore, similarly, a sound speed map showing the distribution of local sound speed values within the set region of interest can be generated.

  Here, the transmission focus for generating the B-mode image and the transmission focus for measuring the sound speed in the first embodiment will be described with reference to FIG. In FIG. 3, for simplification, the transducer array 1 is shown as an array of seven ultrasonic transducers, and the sound rays S1 to S7 are formed at the arrangement pitch of these ultrasonic transducers. It is shown. In the region of interest R, the lattice point E1 indicated by “●” and the lattice point E2 indicated by “◯” are set on the sound ray passing through the region of interest R and spaced from each other in the depth direction. Has been. FIG. 3 shows a total of nine lattice points including six lattice points E1 and three lattice points E2 set on the sound rays S3 to S5 passing through the region of interest R, and a sound velocity map is generated. Therefore, all of these nine lattice points become the transmission focus.

On the other hand, the transmission focus for generating the B-mode image is set to a point F located on a sound ray passing outside the region of interest R and at a predetermined depth. In FIG. 3, the point F is indicated by “Δ”, and among the sound rays S <b> 1 to S <b> 7, a total of four points located at a predetermined depth L <b> 1 on the sound rays S <b> 1, S <b> 2, S <b> 6 and S <b> 7 that pass outside the region of interest R. The transmission focus is set at each of the points F, and the first reception data for generating the B-mode image is acquired by forming the transmission focus at each of the four points F and transmitting and receiving the ultrasonic beam. .
For the sound rays S3 to S5 that pass through the inside of the region of interest R, the transmission focus dedicated for B-mode image generation is not formed, and the most at the predetermined depth L1 among the plurality of lattice points set for sound speed measurement. The reception data for sound velocity measurement obtained by forming transmission focal points at three lattice points E2 having close depths and transmitting / receiving ultrasonic beams is used as second reception data for B-mode image generation. Used.

Next, the operation of the first embodiment will be described.
First, an ultrasonic beam is transmitted from a plurality of ultrasonic transducers of the transducer array 1 in accordance with a drive signal from the transmission circuit 2, and reception signals are received from the ultrasonic transducers that have received ultrasonic echoes from the subject to the reception circuit 3. The received data is generated by the output, and the B-mode image is displayed on the display unit 8 by the display control unit 7 based on the B-mode image signal generated by the image generation unit 15.
Here, when the region of interest R is set on the B-mode image displayed on the display unit 8 by the operation of the operation unit 13 by the operator, the control unit 12 causes the sound passing through the inside of the region of interest R. Nine lattice points are set in the region of interest R so as to be spaced apart from each other by a distance H in the depth direction on the sound lines S3 to S5 in FIG.

Next, the control unit 12 sets a total of four points F located at a predetermined depth L1 on the sound rays S1, S2, S6, and S7 that pass outside the region of interest R. Further, among the nine grid points set in the region of interest R, the three grid points having the depth closest to the predetermined depth L1 are used for both the generation of the B-mode image and the sound speed measurement. And the remaining six grid points are set as grid points E1 that serve as a transmission focal point used exclusively for sound velocity measurement.
Then, a transmission focal point is formed at each of the nine lattice points E1 and E2 in the region of interest R set in this way and four points F outside the region of interest R, and ultrasonic beams are sequentially transmitted and received. Thus, the transmission circuit 2 and the reception circuit 3 are controlled by the control unit 12.
The reception data generated by the reception circuit 3 every time an ultrasonic beam is received is sequentially output to the signal processing unit 4 of the image generation unit 15 and stored in the cine memory 10.

  At this time, the signal processing unit 4, based on a command from the control unit 12, among the received data sequentially input from the receiving circuit 3, four points F outside the region of interest R and three points inside the region of interest R A B-mode image signal is generated using reception data acquired by forming a transmission focal point at the lattice point E2 and transmitting and receiving an ultrasonic beam. That is, the reception data for measuring the sound speed obtained by transmitting and receiving the ultrasonic beam by forming the transmission focus at the three lattice points E2 in the region of interest R is the second reception data for generating the B-mode image. B-mode image generation obtained by transmitting and receiving an ultrasonic beam by forming a transmission focal point at four points F outside the region of interest R and the second reception data for generating the B-mode image A B-mode image signal is generated based on the first received data. The B-mode image signal is raster-converted by the DSC 5, subjected to various image processing by the image processing unit 6, then sent to the display control unit 7, and the B-mode image is displayed on the display unit 8.

  On the other hand, when receiving a sound speed map formation command from the control unit 12, the sound speed map generating unit 11 transmits the transmission focus to nine lattice points E1 and E2 in the region of interest R in the received data stored in the cine memory 10. Is used to calculate the local sound speed value at each lattice point using the received data obtained by transmitting and receiving the ultrasonic beam, and a sound speed map in the region of interest R is generated. Data relating to the sound velocity map obtained by the sound velocity map generator 11 is raster-converted by the DSC 5, subjected to various image processing by the image processor 6, and then sent to the display controller 7. Then, according to the display mode input from the operation unit 13 by the operator, the B-mode image is displayed on the display unit 8 with the sound velocity map superimposed thereon, or the B-mode image and the sound velocity map image are arranged side by side. Is displayed.

  As described above, the reception data for measuring the sound velocity obtained by forming the transmission focal point at the three lattice points E2 in the region of interest R and transmitting / receiving the ultrasonic beam is used as the second B-mode image generation data. By using the received data as reception data, it is possible to efficiently acquire the reception data for generating the B-mode image and the reception data for measuring the sound velocity, and perform both the generation of the B-mode image and the generation of the sound velocity map.

It should be noted that an ultrasonic beam only for generating a B-mode image that is transmitted after forming a transmission focal point at four points F outside the region of interest R, and a transmission focal point at nine lattice points E1 and E2 within the region of interest R. As the ultrasonic beams for measuring the speed of sound transmitted and formed, those having different center frequencies and numerical apertures of the transducer array 1 can be used. For example, an ultrasonic beam having a center frequency of 3 MHz with a numerical aperture of 64 channels is used as an ultrasonic beam only for generating a B-mode image, and an ultrasonic beam having a central frequency of 8 MHz with a numerical aperture of 96 channels is used as an ultrasonic beam for measuring the speed of sound. A sound beam can be used.
The ultrasonic beam for measuring the speed of sound may have a wider aperture for narrowing the transmission focus than the ultrasonic beam for generating the B-mode image, and the center frequency may be set higher to reduce the influence of side lobes. preferable. In the case where there is a high possibility of being affected by refraction due to the abdominal wall or the like as in the case where the liver is to be diagnosed, the center frequency of the ultrasonic beam for sound velocity measurement is set to a low value, for example, 2.5 MHz. , The influence of refraction can be reduced.

  In FIG. 3, among the nine grid points set in the region of interest R, the three grid points E2 located at the deepest part have the depth closest to the predetermined depth L1, and these grid points The point E2 became a transmission focal point used for both generation of the B-mode image and measurement of the sound speed, but as shown in FIG. 4, the center of the nine lattice points set in the region of interest R is shown. When the three lattice points that are positioned have a depth closest to the predetermined depth L1, these lattice points are lattice points E2 that are used for both the generation of the B-mode image and the sound speed measurement.

Embodiment 2
In the first embodiment, the transmission of the ultrasonic beam for generating the B-mode image has one transmission focal point at a predetermined depth on each sound ray. A plurality of transmission focal points may be formed at a plurality of depths on the sound ray. For example, as shown in FIG. 5, a total of four points F1 located at a predetermined depth L1 and positions at a predetermined depth L2 on sound rays S1, S2, S6 and S7 passing outside the region of interest R, respectively. A total of four points F2 are set, a transmission focal point is formed at each of these points F1 and F2, and transmission and reception of ultrasonic beams are sequentially performed.
In this case, a lattice point having the closest depth to each of a plurality of predetermined depths is selected as a lattice point that is used for both generation of the B-mode image and sound speed measurement. In FIG. 5, among the nine grid points set in the region of interest R, the three grid points located at the shallowest part having the depth closest to the predetermined depth L1 and the closest to the predetermined depth L2 A total of six lattice points of the three lattice points located at the deepest part having the depth becomes the lattice point E2 used for both the generation of the B-mode image and the sound speed measurement.

  As shown in FIG. 6, for the convenience of calculating the local sound velocity value of each lattice point in the region of interest R, lattice points are added outside the region of interest R, and the sound velocity is also applied to these outer lattice points. A transmission focus for measurement may be formed. In this case, the lattice point set outside the region of interest R is also the lattice point E2 used for both the generation of the B-mode image and the sound speed measurement, and the received data acquired for the sound speed measurement is used for the B-mode image generation. Used as the second received data. In FIG. 6, among the sound rays S1 to S13, the sound rays S6 to S8 pass through the region of interest R, and the sound rays S1 to S5 and S9 to S13 pass outside the region of interest R.

Embodiment 3
In the first and second embodiments, a plurality of lattice points are set in the region of interest R, and the lattice point has a depth closest to a predetermined depth that forms the transmission focus of the ultrasonic beam for generating the B-mode image. Is used for both the generation of the B-mode image and the sound velocity measurement. Conversely, among the plurality of lattice points set in the region of interest R, the lattice point used for both the generation of the B-mode image and the sound velocity measurement. The transmission focal point for generating the B-mode image may be formed so as to be equal to the depth of.

For example, as shown in FIG. 7, nine lattice points are set in the region of interest R, and among these lattice points, three lattice points located at the center in the depth direction of the region of interest R are represented by B. Assume that the grid point E2 is used for both generation of a mode image and measurement of sound velocity. In this case, a total of four points F on the sound rays S1, S2, S6 and S7 passing outside the region of interest R and having a depth L1 equal to the depth of the grid point E2 are set and transmitted to these points F A focal point is formed and an ultrasonic beam for B-mode image generation is transmitted and received.
Even in this way, it is possible to efficiently acquire the reception data for generating the B-mode image and the reception data for measuring the sound velocity, and perform both the generation of the B-mode image and the sound velocity map.

Embodiment 4
In Embodiment 3 described above, transmission of ultrasonic beams for generating a B-mode image may be made into a multi-stage focus format, and a plurality of transmission focal points may be formed at a plurality of depths on the same sound ray. For example, as shown in FIG. 8, among the nine lattice points set in the region of interest R, three lattice points located at the shallowest part and three lattice points located at the deepest part are represented by B. A lattice point E2 used for both generation of the mode image and sound speed measurement, and a depth equal to the depth of the shallowest lattice point E2 on each of the sound rays S1, S2, S6 and S7 passing outside the region of interest R. Four points F1 having L1 are set, and four points F2 having a depth L2 equal to the depth of the deepest lattice point E2 are set. A transmission focal point is formed at each of these points F1 and F2 to form B Transmission / reception of an ultrasonic beam for mode image generation is performed.

As shown in FIG. 9, for the convenience of calculating the local sound velocity value of each lattice point in the region of interest R, lattice points are added outside the region of interest R, and the sound velocity is also applied to these outer lattice points. A transmission focus for measurement may be formed. In this case, the lattice point set outside the region of interest R is also the lattice point E2 used for both the generation of the B-mode image and the sound speed measurement, and the received data acquired for the sound speed measurement is used for the B-mode image generation. Used as the second received data.
As shown in FIG. 10, when the region of interest R is long in the depth direction, among the plurality of lattice points set in the region of interest R, the lattice point located at the shallowest part and the deepest part are located. For example, a lattice point located at an inner side of the depth distance of the region of interest R, for example, about 1/4 of the depth distance of the region of interest R from the lattice point to be used as a lattice point E2 used for both generation of the B-mode image and sound speed measurement. Also good.

In the first to fourth embodiments described above, the reception data output from the reception circuit 3 is temporarily stored in the cine memory 10, and the sound speed map generation unit 11 uses the reception data stored in the cine memory 10 to store the reception data in the region of interest R. The sound speed map in the region of interest R is generated by calculating the local sound speed value at each lattice point of the sound field, but the sound speed map generation unit 11 directly inputs the reception data output from the receiving circuit 3 to generate the sound speed map. You can also.
The cine memory 10 stores not only received data used for sound velocity measurement but also received data for generating a B-mode image. Therefore, the control unit 12 controls the cine memory 10 from the cine memory 10 as necessary. It is also possible to read out reception data for image generation and generate a B-mode image by the image generation unit 15.

  In the first to fourth embodiments described above, for the sake of simplicity, the numerical aperture of the transducer array 1 illustrated, that is, the number of sound rays, the number of lattice points in the region of interest R, and the like are shown as small values. However, the present invention is not limited to this, and it is preferable to set the numerical aperture and the number of lattice points suitable for diagnosis using a B-mode image and measurement of sound speed.

  1 transducer array, 2 transmitting circuit, 3 receiving circuit, 4 signal processing unit, 5 DSC, 6 image processing unit, 7 display control unit, 8 display unit, 9 image memory, 10 cine memory, 11 sound velocity map generation unit, 12 control Unit, 13 operation unit, 14 storage unit, 15 image generation unit, X, A1, A2 lattice points, W1, W2, Wx received wave, Wsum synthetic wave, R region of interest, S1-S13 sound ray, E1 Dedicated to sound velocity measurement Lattice points where transmission focal points are formed, lattice points where transmission focal points used for both E2 B-mode image generation and sound velocity measurement are formed, and transmission focal points dedicated to F, F1, F2 B-mode image generation are formed , L1, L2 predetermined depth, H interval.

Claims (6)

Based on the drive signal supplied from the transmission circuit, an ultrasonic beam is transmitted from the transducer array of the ultrasonic probe toward the subject and the ultrasonic echo by the subject is received from the transducer array of the ultrasonic probe. An ultrasonic diagnostic apparatus that generates an ultrasonic image based on reception data obtained by processing an output reception signal in a reception circuit,
A region-of-interest setting unit for setting a region of interest in the imaging region;
A plurality of lattice points are set on a sound ray passing through the inside of the region of interest set by the region of interest setting unit and in the region of interest, and a transmission focal point is formed at the plurality of lattice points to transmit / receive ultrasonic beams respectively. B-mode image is obtained by acquiring reception data for sound velocity measurement by performing and transmitting and receiving an ultrasonic beam while forming a transmission focal point at least at a predetermined depth with respect to a sound ray passing outside the region of interest. A control unit that controls the transmission circuit and the reception circuit so as to obtain first reception data for generation;
A sound speed map generating unit for generating a sound speed map in the region of interest based on the received data for sound speed measurement;
A sound ray passing through the inside of the region of interest is obtained by transmitting and receiving an ultrasonic beam by forming a transmission focal point at a lattice point having a depth closest to the predetermined depth among the plurality of lattice points. An image generation unit for generating the B-mode image based on the first and second reception data for generating the B-mode image, wherein the received data for measuring the sound velocity is set as second reception data for generating the B-mode image. An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein the control unit sets the predetermined depth to be equal to any one of the plurality of lattice points.   The ultrasonic diagnosis according to claim 2, wherein the control unit sets the predetermined depth to be equal to a depth of a lattice point located at a central portion in a depth direction of the region of interest among the plurality of lattice points. apparatus.   The ultrasonic diagnostic apparatus according to claim 1, wherein the control unit sets a plurality of the predetermined depths for a sound ray passing outside the region of interest.   5. The ultrasonic diagnosis according to claim 4, wherein the control unit sets two predetermined depths equal to a depth of a lattice point located at a shallowest portion and a lattice point located at a deepest portion among the plurality of lattice points. apparatus. Based on the drive signal supplied from the transmission circuit, an ultrasonic beam is transmitted from the transducer array of the ultrasonic probe toward the subject and the ultrasonic echo by the subject is received from the transducer array of the ultrasonic probe. An ultrasonic image generation method for generating an ultrasonic image based on reception data obtained by processing an output reception signal in a reception circuit,
Setting a region of interest in the imaging region and setting a plurality of grid points on a sound ray passing through the inside of the region of interest and in the region of interest;
Obtaining reception data for sound velocity measurement by forming transmission focal points at the plurality of lattice points and transmitting and receiving ultrasonic beams respectively.
Generating a sound speed map in the region of interest based on the received data for sound speed measurement;
First transmission data for B-mode image generation is acquired by forming a transmission focal point at least at a predetermined depth with respect to a sound ray passing outside the region of interest, and transmitting and receiving an ultrasonic beam;
A sound ray passing through the inside of the region of interest is obtained by transmitting and receiving an ultrasonic beam by forming a transmission focal point at a lattice point having a depth closest to the predetermined depth among the plurality of lattice points. The received data for measuring sound speed is used as second received data for generating a B-mode image, and a B-mode image is generated based on the first and second received data for generating a B-mode image. An ultrasonic image generation method.

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