JP2012192075A - Ultrasound diagnostic apparatus and ultrasound image generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic apparatus for generating a precise sound speed map by reducing influences by refraction of ultrasonic beam received from the abdominal wall while corresponding to areas in a wide range and generating a B mode image of good image quality.SOLUTION: When a shape of the abdominal wall of a subject detected on the B mode image is almost linear (S4), ultrasonic beam for a sound speed map is transmitted/received by a linear scanning array part of a vibrator array while being subjected to linear scanning with respect to a region of interest ROI to generate a sound speed map in the region of interest ROI (S5), furthermore, ultrasonic beam for the B mode image is transmitted/received while being subjected to linear scanning by the linear scanning array part of the vibrator array with respect to an entire photography area, and also, the ultrasonic beam for the B mode image is transmitted/received while being subjected to convex scanning by a convex scanning array part to generate the B mode image (S6), and the B mode image and the sound speed map image are displayed (S7).

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.

  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. Furthermore, if a sound speed map showing the distribution of local sound speed values at each point in a predetermined area is generated and displayed together with the B-mode image, it is effective in diagnosing the diagnosis site.

Further, as an ultrasonic probe, Patent Document 2 proposes a composite probe having a transducer array in which a convex scanning array unit and a linear scanning array unit are continuously arranged.
By transmitting and receiving an ultrasonic beam using such a composite ultrasonic probe, it is possible to expand the visual field in the deep region while obtaining a large viewing angle and high image quality in the shallow region of the subject. Thus, a B-mode image suitable for ultrasonic diagnosis can be obtained.

JP 2010-99452 A JP 2010-2114015 A

  However, the vicinity of the abdominal wall covering the internal organs of the subject has a sound velocity different from other parts due to the presence of fat and the like. Therefore, the composite as described in Patent Document 2 is used. Even if we try to obtain the local sound velocity value at the diagnostic site using a type of ultrasonic probe, when the ultrasonic beam transmitted from the transducer array passes through the abdominal wall, the ultrasonic beam may be refracted depending on the incident angle to the abdominal wall. As a result, there is a problem that the speed of sound cannot be measured accurately.

  The present invention has been made in order to solve such a conventional problem, and it is possible to generate a B-mode image having a good image quality while corresponding to a wide range of areas, and to influence the refraction of the ultrasonic beam received from the abdominal wall. It is an object to provide an ultrasonic diagnostic apparatus and an ultrasonic image generation method capable of generating an accurate sound velocity map with reduced noise.

  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 for generating a B-mode image in an image generation unit based on reception data obtained by processing a reception signal output from a transducer array of an ultrasonic probe by a reception circuit. The transducer array includes a convex scanning array unit and a linear scanning array unit arranged in succession, and detects an abdominal wall of a subject on a B-mode image generated by the image generation unit. When the shape of the abdominal wall detected by the abdominal wall detection unit and the abdominal wall detection unit is substantially linear, the ultrasonic beam for the sound velocity map is linearly scanned from the linear scanning array unit of the transducer array. And a control unit for controlling the transmission circuit and the reception circuit so as to acquire the reception data for the sound velocity map, and a sound speed map generation unit for generating the sound speed map based on the acquired reception data for the sound velocity map. Is.

A region-of-interest setting unit for setting a region of interest on the B-mode image generated by the image generation unit is further provided, and the abdominal wall detection unit is configured to detect a subject positioned above the region of interest set by the region-of-interest setting unit. It is preferable to be configured to detect the abdominal wall.
In addition, the control unit may control the transmission circuit and the reception circuit so as not to transmit / receive the ultrasonic beam for the sonic velocity map when the shape of the abdominal wall detected by the abdominal wall detection unit is not substantially linear.
Further, the control unit transmits / receives the ultrasonic beam for B-mode image from the convex scanning array unit of the transducer array while performing the convex scanning, and transmits / receives the ultrasonic beam for sound velocity map from the linear scanning array unit while performing the linear scanning. The transmission circuit and the reception circuit are controlled so as to acquire the B-mode image reception data, and the image generation unit can generate the B-mode image based on the B-mode image reception data.

  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 a B-mode 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, When the abdominal wall of the subject is detected and the shape of the detected abdominal wall is substantially linear, the array array for the linear scan and the array array for the linear scan among the array sections for the linear scan and the array array for the transducer array arranged in succession to each other The transmission circuit and the reception circuit are controlled so as to obtain the reception data for the sound velocity map by linearly scanning and transmitting the ultrasonic beam for the sound velocity map from the unit. A method of generating a sound speed map on the basis of the sound speed map for received data.

  According to the present invention, when the abdominal wall of the subject is detected and the shape of the abdominal wall is substantially linear, the ultrasonic velocity beam for sound velocity map is transmitted and received from the linear scanning array portion of the transducer array while performing linear scanning. Since the reception data for maps is acquired, a B-mode image with good image quality while supporting a wide range using a transducer array having a convex scanning array unit and a linear scanning array unit arranged successively. While generating, it is possible to reduce the influence of refraction of the ultrasonic beam received from the abdominal wall and generate an accurate sound velocity map.

1 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. It is a figure which shows the composite type ultrasonic probe used in embodiment. It is a figure which shows a B mode image typically. It is a figure which shows typically the principle of the sound speed calculation in embodiment. It is a flowchart which shows operation | movement of embodiment. It is a figure which shows the ultrasonic beam for B mode images transmitted from the ultrasonic probe. It is a figure which shows the ultrasonic beam for sound velocity maps transmitted from the ultrasonic probe.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows the configuration of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. The ultrasonic diagnostic apparatus includes an ultrasonic probe 1 and a diagnostic apparatus main body 2 connected to the ultrasonic probe 1.
The ultrasonic probe 1 is a composite probe, and has a transducer array 3 in which a convex scanning array unit and a linear scanning array unit are continuously arranged. A reception circuit 5 is connected, and a probe control unit 6 is connected to the transmission circuit 4 and the reception circuit 5.

The diagnostic apparatus main body 2 has a signal processing unit 11 connected to the receiving circuit 5 of the ultrasonic probe 1, and includes a DSC (Digital Scan Converter) 12, an image processing unit 13, a display control unit 14, and the signal processing unit 11. The display unit 15 is sequentially connected. An image memory 16 and an abdominal wall detection unit 17 are connected to the image processing unit 13. Furthermore, the diagnostic apparatus body 2 includes a cine memory 18 and a sound velocity map generator 19 connected to the receiving circuit 5 of the ultrasonic probe 1. A main body control unit 20 is connected to the signal processing unit 11, DSC 12, display control unit 14, abdominal wall detection unit 17, cine memory 18, and sound velocity map generation unit 19. Furthermore, an operation unit 21 and a storage unit 22 are connected to the main body control unit 20.
Further, the probe control unit 6 of the ultrasonic probe 1 and the main body control unit 20 of the diagnostic apparatus main body 2 are connected to each other.

As shown in FIG. 2, the transducer array 3 of the ultrasonic probe 1 includes one linear scanning array part G1 and a pair of convex scans continuously arranged on both sides of the linear scanning array part G1. It is comprised from the array part G2. The linear scanning array section G1 has a plurality of ultrasonic transducers arranged in a straight line. Each convex scanning array section G2 has a plurality of ultrasonic transducers that are continuous and fan-shaped with respect to the ultrasonic transducers of the linear scanning array section G1.
The plurality of ultrasonic transducers of the linear scanning array unit G1 and the convex scanning array unit G2 transmit ultrasonic waves according to the drive signals supplied from the transmission circuit 4, and receive and receive ultrasonic echoes from the subject. Output a 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 4 includes, for example, a plurality of pulsers, and is transmitted from the plurality of ultrasonic transducers of the transducer array 3 based on the transmission delay pattern selected according to the control signal from the probe control unit 6. The delay amount of each drive signal is adjusted so that the ultrasonic wave forms an ultrasonic beam and supplied to the plural ultrasonic transducers.

The reception circuit 5 amplifies the reception signal transmitted from each ultrasonic transducer of the transducer array 3 and performs A / D conversion, and then, based on the reception delay pattern selected according to the control signal from the probe control unit 6. In accordance with the sound speed or sound speed distribution set in the above, reception focus processing 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 probe controller 6 controls each part of the ultrasonic probe 1 based on various control signals transmitted from the body controller 20 of the diagnostic apparatus body 2.

The signal processing unit 11 of the diagnostic apparatus main body 2 corrects the attenuation by the distance according to the depth of the reflection position of the ultrasonic wave on the reception data generated by the reception circuit 6 of the ultrasonic probe 1, and then the envelope By performing the detection process, a B-mode image signal that is tomographic image information related to the tissue in the subject is generated.
The DSC 12 converts (raster conversion) the B-mode image signal generated by the signal processing unit 11 into an image signal in accordance with a normal television signal scanning method.
The image processing unit 13 performs various necessary image processing such as gradation processing on the B-mode image signal input from the DSC 12, and then outputs the B-mode image signal to the display control unit 14 or stores it in the image memory 16. Store.
These signal processing unit 11, DSC 12, image processing unit 13 and image memory 16 form an image generation unit 23.

The display control unit 14 causes the display unit 15 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 13.
The display unit 15 includes a display device such as an LCD, for example, and displays an ultrasound diagnostic image under the control of the display control unit 14.

The abdominal wall detection unit 17 is based on the B-mode image signal that has been subjected to image processing by the image processing unit 13 as shown in FIG. 3 and is located above the region of interest ROI set in the B-mode image. The abdominal wall P of the specimen is detected.
The cine memory 18 sequentially stores reception data output from the reception circuit 5 of the ultrasonic probe 1. Further, the cine memory 18 stores information related to the frame rate input from the main body control unit 20 (for example, parameters indicating the reflection position depth, scanning line density, and field width) in association with the received data. .
The sound velocity map generation unit 19 calculates a local sound velocity value in the tissue in the subject to be diagnosed based on the reception data stored in the cine memory 18 under the control of the main body control unit 20, and obtains the sound velocity map. Generate.
The main body control unit 20 controls each part of the ultrasonic diagnostic apparatus based on a command input from the operation unit 21 by the operator.

The operation unit 21 is for an operator to perform an input operation. The operation unit 21 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 22 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 11, the DSC 12, the image processing unit 13, the display control unit 14, and the sound velocity map generation unit 19 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 21. 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, a plurality of ultrasonic waves of the linear scanning array section G1 and the convex scanning array section G2 of the transducer array 3 according to the drive signal supplied from the transmission circuit 4 of the ultrasonic probe 1 are used. Ultrasonic waves are transmitted from the transducers, and reception signals are output to the reception circuit 5 from the respective ultrasonic transducers that have received the ultrasonic echoes from the subject. The reception circuit 5 generates reception data. Further, the B-mode image signal is generated by the signal processing unit 11 of the diagnostic apparatus main body 2 to which the received data is input, the B-mode image signal is raster-converted by the DSC 12, and various B-mode image signals are converted into the B-mode image signal by the image processing unit 13. After the image processing is performed, an ultrasonic diagnostic image is displayed on the display unit 15 by the display control unit 14 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. 4A, 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 ultrasonic waves are transmitted into the subject. 4B, 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 5 of the ultrasonic probe 1. Furthermore, similarly, a sound speed map showing the distribution of local sound speed values within the set region of interest can be generated.

Next, the operation of the first embodiment will be described with reference to the flowchart of FIG.
First, in step S1, a B-mode image is generated. At this time, in accordance with the drive signal from the transmission circuit 4 of the ultrasonic probe 1, as shown in FIG. 6, the B-mode image is linearly scanned from a plurality of ultrasonic transducers in the linear scanning array section G1 of the transducer array 3. The ultrasonic beam B1 for B-mode image is transmitted / received while being subjected to convex scanning from a plurality of ultrasonic transducers of the convex scanning array section G2. A reception signal received by each ultrasonic transducer is output to the reception circuit 5 to generate reception data for the B-mode image. Further, based on the B-mode image signal generated by the image generation unit 23 of the diagnostic apparatus body 2. Then, the B-mode image is displayed on the display unit 15 by the display control unit 14.

  When the region of interest ROI is set on the B-mode image displayed on the display unit 15 by the operator operating the operation unit 21 in step S2, as shown in FIG. 3 in step S3, The abdominal wall P of the subject positioned above the region of interest ROI is detected by the abdominal wall detection unit 17, and the shape of the abdominal wall P of the subject detected by the main body control unit 20 by the main body control unit 20 is substantially the same in step S4. It is determined whether or not it is linear.

  If it is determined that the shape of the abdominal wall P is substantially linear, the process proceeds to step S5, and as shown in FIG. 7, the sound velocity from the linear scanning array section G1 of the transducer array 3 with respect to the region of interest ROI. The map ultrasonic wave G3 is transmitted and received while performing linear scanning, and a sound velocity map in the region of interest ROI is generated.

  That is, a plurality of grid points are set in the region of interest ROI by the main body control unit 20, a transmission focal point is formed at each of these grid points, and ultrasonic waves for sound velocity maps are sequentially scanned from the linear scanning array unit G1. Transmission / reception of the beam B3 is performed. At this time, since the shape of the abdominal wall P is substantially linear, as shown in FIG. 7, a plurality of sonic velocity map ultrasonic beams B3 are transmitted in parallel from the linear scanning array portion G1 of the transducer array 3. However, each sound velocity map ultrasonic beam B3 is incident substantially perpendicularly to the abdominal wall P, and is transmitted through the abdominal wall P to each lattice point in the region of interest ROI with almost no influence of refraction from the abdominal wall P. A focal point will be formed. Then, ultrasonic echoes from the subject are received by the plurality of ultrasonic transducers of the linear scanning array unit G1.

  The reception data for the sonic velocity map generated by the receiving circuit 5 every time the sonic velocity map ultrasonic beam B3 is received is sequentially stored in the cine memory 18. When the reception data for the sound velocity map is acquired for all the lattice points in the region of interest ROI, a sound velocity map formation command is output from the main body control unit 20 to the sound velocity map generation unit 19, and the sound velocity map generation unit 19 The local sound velocity value at each lattice point is calculated using the reception data for the sound velocity map stored in 18, and a sound velocity map in the region of interest ROI is generated. Data relating to the sound velocity map obtained by the sound velocity map generator 19 is raster-converted by the DSC 12 and subjected to various types of image processing by the image processor 13.

  When the sound velocity map in the region of interest ROI is generated in this way, in step S6, the B-mode image ultrasonic wave is linearly scanned from the linear scanning array portion G1 of the transducer array 3 over the entire imaging region. The beam B1 is transmitted and received and the B-mode image ultrasonic beam B2 is transmitted and received while performing convex scanning from the convex scanning array unit G2, thereby generating a B-mode image.

  That is, a reception signal is output to the receiving circuit 5 from each ultrasonic transducer that has received the ultrasonic echo of the B-mode image ultrasonic beam B1 transmitted from the linear scanning array unit G1, and from the convex scanning array unit G2. Received signals are output from the ultrasonic transducers that have received the ultrasonic echoes of the transmitted B-mode image ultrasonic beam B2 to the reception circuit 5 to generate B-mode image reception data. The B-mode image reception data Is stored in the cine memory 18 of the diagnostic apparatus body 2 and is input to the signal processing unit 11 to generate a B-mode image signal. The DSC 12 raster-converts the B-mode image signal and the image processing unit 13 performs the B-mode image signal. Various kinds of image processing are performed.

  In step S7, data relating to the sound velocity map in the region of interest ROI that has been subjected to various types of image processing by the image processing unit 13 and the B-mode image signal are sent to the display control unit 14 and input from the operation unit 21 by the operator. According to the displayed display mode, the sound speed map is superimposed on the B mode image and displayed on the display unit 15, or the B mode image and the sound speed map image are displayed side by side on the display unit 15.

Further, whether or not to end the inspection is confirmed in step S8, and if the inspection is continued, the process returns to step S1, and if the inspection is ended, a series of processing is completed.
If it is determined in step S4 that the shape of the abdominal wall P is not substantially linear, the sonic velocity map ultrasonic beam B3 is linearly scanned from the linear scanning array portion G1 of the transducer array 3 of the ultrasonic probe 1. Even if transmission / reception is performed, the incident angle of the ultrasonic beam B3 for the sound velocity map with respect to the abdominal wall P is increased and is greatly affected by refraction from the abdominal wall P, so that the sound velocity map in the region of interest ROI cannot be generated with high accuracy. As described above, the transmitting circuit 4 and the receiving circuit 5 are controlled so as not to transmit / receive the ultrasonic beam B3 for the sonic velocity map, and a warning is given to the display unit 15 and the like in step S9, and then the process proceeds to step S8 to end the inspection. It is confirmed whether or not.

Note that the determination of whether or not the shape of the abdominal wall P in step S4 is substantially linear can be performed, for example, as follows.
First, a plurality of measurement points Qi (i = 1 to n) are set on the abdominal wall P detected by the abdominal wall detection unit 17, and the least square method is used by using the coordinates (Xi, Yi) of these measurement points Qi on the image. Thus, an approximate straight line is obtained, and the coefficient of variation CV of the residual dYi at each measurement point Qi at this time is calculated.
When the average value of the residuals dYi at a plurality of measurement points Qi is dYm, the variation coefficient CV of the residuals dYi is
CV = [(1 / n) Σ (dYi ² −dYm ² )] ^1/2 / dYm (1)
It is represented by Note that Σ represents the total sum for i = 1 to n.
Therefore, for example, when the threshold CV1 = 0.1 is set as the allowable range and the variation coefficient CV of the residual dYi calculated by the above equation (1) is equal to or less than the threshold CV1, the shape of the abdominal wall P Is substantially linear, and when it is larger than the set value CV1, it can be determined that the shape of the abdominal wall P is not substantially linear.

  Note that the threshold value CV1 is not limited to “0.1”, and the ultrasonic wave for the sound velocity map is actually transmitted and received while linear scanning is performed, and the disturbance of the wavefront does not adversely affect the sound velocity measurement. It is preferable to obtain the threshold value CV1.

Moreover, a correlation coefficient can also be used for determination of whether the shape of the abdominal wall P is substantially linear in step S4.
That is, a plurality of measurement points Qi (i = 1 to n) are set on the abdominal wall P detected by the abdominal wall detection unit 17, and the correlation coefficient r of the coordinates (Xi, Yi) on the image of these measurement points Qi is set. calculate.
When the average value of Xi is Xm and the average value of Yi is Ym, the correlation coefficient r is
r = Σ [(Xi−Xm) (Yi−Ym)] / [Σ (Xi−Xm) ² Σ (Yi−Ym) ² ] ^1/2
... (2)
It is represented by Note that Σ represents the total sum for i = 1 to n.
Therefore, for example, when the threshold value r1 = 0.7 is set as the allowable range, and the absolute value of the correlation coefficient r calculated by the above equation (2) is equal to or greater than the threshold value r1, the shape of the abdominal wall P Is substantially linear, and when it is less than the threshold value r1, it is determined that the shape of the abdominal wall P is not substantially linear.
Also in this case, the threshold value r1 is not limited to “0.7”, and is preferably set to a value suitable for actual measurement.

In this way, it is determined whether or not the shape of the abdominal wall P detected by the abdominal wall detection unit 17 is substantially linear. Only when the abdominal wall P is substantially linear, the velocity of sound from the linear scanning array unit G1 of the transducer array 3 Since the map ultrasonic beam B3 is transmitted and received while performing linear scanning, the composite ultrasonic probe 1 having the transducer array 3 in which the linear scanning array unit G1 and the convex scanning array unit G2 are continuously arranged with each other. It is possible to reduce the influence of refraction received from the abdominal wall P while using, and to generate an accurate sound velocity map.
Further, the B-mode image ultrasonic beam B2 is transmitted / received while performing linear scanning from the linear scanning array unit G1 of the transducer array 3 and is also subjected to convex scanning from the convex scanning array unit G2. Therefore, it is possible to generate a B-mode image with good image quality while supporting a wide area.

In the above embodiment, the reception data output from the reception circuit 5 is temporarily stored in the cine memory 18, and the sound velocity map generation unit 19 uses the reception data stored in the cine memory 18 at each lattice point in the region of interest ROI. Although the local sound speed value is calculated and the sound speed map in the region of interest ROI is generated, the sound speed map generating unit 19 can directly generate the sound speed map by directly receiving the reception data output from the receiving circuit 5.
Since the cine memory 18 stores not only the reception data for the sound velocity map but also the reception data for generating the B-mode image, the B-mode image is generated from the cine memory 18 as necessary under the control of the main body control unit 20. It is also possible to read out the received data and generate a B-mode image by the image generation unit 23.
Note that the connection between the ultrasonic probe 1 and the diagnostic apparatus main body 2 in the above embodiment can take either a wired connection or a wireless communication connection.

  1 transducer probe, 2 diagnostic device body, 3 transducer array, 4 transmission circuit, 5 reception circuit, 6 probe control unit, 11 signal processing unit, 12 DSC, 13 image processing unit, 14 display control unit, 15 display unit, 16 image memory, 17 abdominal wall detection unit, 18 cine memory, 19 sound velocity map generation unit, 20 main body control unit, 21 operation unit, 22 storage unit, 23 image generation unit, G1 linear scanning array unit, G2 convex scanning array unit, P abdominal wall, ROI region of interest, X, A1, A2 lattice points, W1, W2, Wx received wave, Wsum synthesized wave, B1, B2 ultrasonic beam for B-mode image, B3 ultrasonic beam for sonic velocity map.

Claims (5)

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 a B-mode image in an image generation unit based on reception data obtained by processing an output reception signal in a reception circuit,
The transducer array of the ultrasonic probe has a convex scanning array part and a linear scanning array part arranged continuously,
An abdominal wall detection unit for detecting the abdominal wall of the subject on the B-mode image generated by the image generation unit;
When the shape of the abdominal wall detected by the abdominal wall detection unit is substantially linear, the ultrasonic velocity beam for ultrasonic velocity map is transmitted / received from the linear scanning array unit of the transducer array while linearly scanning the received data for the acoustic velocity map. A control unit for controlling the transmission circuit and the reception circuit to obtain;
An ultrasonic diagnostic apparatus comprising: a sound speed map generating unit that generates a sound speed map based on the acquired reception data for the sound speed map. A region of interest setting unit for setting a region of interest on the B-mode image generated by the image generation unit;
The ultrasonic diagnostic apparatus according to claim 1, wherein the abdominal wall detection unit detects an abdominal wall of a subject located above the region of interest set by the region of interest setting unit.   The said control part controls the said transmission circuit and the said receiving circuit so that transmission / reception of the ultrasonic beam for sound velocity maps may not be performed when the shape of the abdominal wall detected by the said abdominal wall detection part is not substantially linear. The ultrasonic diagnostic apparatus according to 1 or 2. The control unit transmits / receives a B-mode image ultrasonic beam from the convex scanning array unit of the transducer array while performing convex scanning, and transmits / receives a sound velocity map ultrasonic beam from the linear scanning array unit while performing linear scanning. Controlling the transmitting circuit and the receiving circuit so as to obtain B-mode image reception data,
The ultrasonic diagnostic apparatus according to claim 1, wherein the image generation unit generates a B-mode image based on the B-mode image reception data. 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 a B-mode image based on reception data obtained by processing an output reception signal in a reception circuit,
Detecting the abdominal wall of the subject on the B-mode image;
When the shape of the detected abdominal wall is substantially linear, the ultrasonic wave for the sound velocity map from the linear scanning array unit among the convex scanning array unit and the linear scanning array unit arranged in succession to each other of the transducer array. Controlling the transmission circuit and the reception circuit so as to acquire the reception data for the sound velocity map by transmitting and receiving while linearly scanning the beam;
An ultrasonic image generation method, wherein a sound velocity map is generated based on the acquired reception data for the sound velocity map.

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