JP2011056160A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability of a display image of an object tissue in unstable periodic motion. <P>SOLUTION: A representative part memory 15 stores echo data collected from a representative part of an object tissue. A virtual period setting unit 22 sets a virtual period as a temporary period of the motion of the object tissue on the basis of the echo data of a plurality of time phase stored in the representative part memory 15. A mutual difference value is used to calculate the virtual period. A pre-memory 14 stores a plurality of tomographic image data in time-series order. A reference image searching section 24 extracts a plurality of reference images from a plurality of tomographic images using the set virtual period. A reconstruction processing unit 20 divides the plurality of tomographic image data into a plurality of image groups by using each of the plurality of reference images as a division unit. A three-dimensional image is reconstructed by extracting, from the plurality of image groups, a plurality of sets of tomographic image data that correspond periodically to each other. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus that forms a display image of a target tissue that moves periodically.

  2. Description of the Related Art An ultrasonic diagnostic apparatus that forms a three-dimensional ultrasonic image of a tissue that accompanies motion such as the heart is known. For example, there is a technology that scans an ultrasonic beam in a three-dimensional space, collects echo data from the three-dimensional space, forms a three-dimensional ultrasonic image based on the collected echo data, and displays it in real time. It has been. However, in the case of real-time display, there is a principle restriction that the scan rate, the beam density, and the beam range are in a trade-off relationship with each other.

  Techniques for avoiding the fundamental limitations in real-time display of 3D ultrasound images have also been proposed. For example, Patent Document 1 collects a plurality of tomographic image data over a plurality of time phases at each position on the scanning plane while moving the scanning plane little by little in the three-dimensional space in synchronization with an electrocardiogram signal or the like. A technique (reconstruction processing) is described in which a plurality of collected tomographic image data is rearranged and reconstructed to form three-dimensional image data. This technique is difficult to apply to a fetus or the like for which it is difficult to directly obtain an electrocardiogram signal.

  Patent Document 2 describes a technique for scanning and reconstructing at certain time intervals instead of an electrocardiographic signal. However, this technique assumes that the period of the heart, etc. during data collection is constant, so that, for example, if the period of the heart is not constant, the shape of the heart in the reconstructed image is distorted from the actual one. Reliability may be reduced.

Japanese Patent No. 3537594 JP 2005-74225 A

  In view of the background art described above, the inventor of the present application has repeatedly researched and developed a technique for forming an ultrasonic image by reconstruction processing. In particular, we focused on techniques for forming ultrasound images of target tissues with unstable movement cycles, such as the fetal heart.

  The present invention has been made in the course of research and development, and an object thereof is to increase the reliability of a display image of a target tissue having an unstable motion cycle.

  An ultrasonic diagnostic apparatus suitable for the above-described object includes a probe that transmits and receives ultrasonic waves in a three-dimensional space including a target tissue that periodically moves, and a plurality of cycles of the movement by controlling the probe. A transmission / reception control unit that collects reception signals from a representative part of a target tissue and further forms a plurality of scanning planes in the three-dimensional space while moving the scanning plane over a plurality of cycles of the movement, and the representative part A virtual period setting unit for setting a virtual period of motion related to the target tissue based on the received signal collected from the plurality of references at intervals corresponding to the virtual period from among a plurality of images corresponding to the plurality of scanning planes A reference image search unit for searching for an image, and dividing each of the plurality of reference images into a plurality of image groups by using each of the plurality of reference images as a unit of division, and periodically matching each other from each of the plurality of image groups. An image reconstruction unit for extracting a plurality of images, characterized in that and a display image forming unit for forming a display image of the target tissue based on a plurality of images periodically correspond to one another.

  As a desirable specific example, the virtual cycle setting unit calculates a feature amount that reflects a change in the received signal between time phases based on the received signals of a plurality of time phases collected from the representative part, and calculates the feature amount. The virtual period is determined on the basis of this.

  As a desirable specific example, the virtual cycle setting unit calculates a mutual difference value for each time phase as the feature amount, and the virtual cycle based on temporal changes of the mutual difference values obtained over a plurality of time phases. It is characterized by determining.

  As a desirable specific example, the virtual cycle setting unit is characterized in that the virtual cycle is determined based on a time phase interval corresponding to a maximum value of a mutual difference value obtained over a plurality of time phases.

  As a desirable specific example, the virtual cycle setting unit uses reception signals of a plurality of time phases collected one-dimensionally from an ultrasonic beam set in the representative part.

  As a desirable specific example, the virtual cycle setting unit uses reception signals of a plurality of time phases collected two-dimensionally from the scanning plane set in the representative part.

  As a preferred specific example, the transmission / reception control unit forms a plurality of scanning planes in the three-dimensional space after collecting reception signals from the representative part.

  As a desirable specific example, the transmission / reception control unit collects reception signals from the representative portion after forming a plurality of scanning planes in the three-dimensional space.

  As a preferred specific example, the reference image search unit sets one image corresponding to the maximum mutual difference value as a representative reference image based on the mutual difference value corresponding to each of the plurality of images, and the representative reference image is used as the representative reference image. As a starting point, an image closest to a position separated by the virtual period is searched one after another from a plurality of images corresponding to the maximum mutual difference value, and is set as the plurality of reference images.

  According to the present invention, it is possible to improve the reliability of a display image for a target tissue whose movement cycle is unstable.

1 is a block diagram showing a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention. It is a figure for demonstrating the three-dimensional scanning in this embodiment. It is a figure which shows the change of a cross-sectional difference value. It is a figure which shows the change of the mutual difference value regarding a representative site | part. It is a figure for demonstrating the search of a reference | standard image. It is a figure for demonstrating the process by the reconstruction process part. It is a figure for demonstrating another suitable process by the reconstruction process part.

  Hereinafter, preferred embodiments of the present invention will be described.

  FIG. 1 is a diagram showing an overall configuration of an ultrasonic diagnostic apparatus suitable for implementing the present invention. The probe 10 transmits and receives ultrasonic waves in a three-dimensional space including the target tissue. The probe 10 includes a plurality of vibration elements each of which transmits / receives an ultrasonic wave, and transmission of the plurality of vibration elements is controlled by the beam former 12 to form a transmission beam. Further, the plurality of vibration elements receive the ultrasonic waves reflected from the target tissue, and signals obtained thereby are output to the beam former 12, and the beam former 12 forms a reception beam.

  The probe 10 of the present embodiment is a 3D probe that collects echo data three-dimensionally by scanning an ultrasonic beam (a transmission beam and a reception beam) in a three-dimensional space. For example, the ultrasonic beam is scanned three-dimensionally by mechanically moving a scanning surface formed electronically by a plurality of vibration elements (1D array transducers) arranged one-dimensionally. Alternatively, the ultrasonic beam may be scanned three-dimensionally by electronically controlling a plurality of vibration elements (2D array transducers) arranged two-dimensionally.

  The beam former 12 forms an ultrasonic transmission beam by supplying a transmission signal corresponding to each of a plurality of vibration elements included in the probe 10. In addition, the beam former 12 forms an ultrasonic reception beam by performing a phasing addition process or the like on a reception signal obtained from each of a plurality of vibration elements included in the probe 10, and is obtained along the reception beam. Output echo data. In the present embodiment, the target tissue is a periodically moving tissue, such as a fetal heart.

  FIG. 2 is a diagram for explaining three-dimensional scanning in the present embodiment. In FIG. 2, the three-dimensional space including the target tissue is expressed in an XYZ orthogonal coordinate system. In the present embodiment, the scanning surface S is formed so as to be substantially parallel to the XY plane, and a plurality of scanning surfaces S are formed along the Z-axis direction while slowly moving the scanning surface S in the Z-axis direction. It is formed. The scanning plane S moves slowly in the Z-axis direction over a plurality of periods related to periodic movements such as the fetal heart, for example, over a period including about 20 heartbeats in about 8 seconds.

  Returning to FIG. 1, when a plurality of scanning planes are formed along the Z-axis direction over a plurality of periods of the fetal heartbeat, tomographic image data is collected for each scanning plane and corresponds to the plurality of scanning planes. A plurality of tomographic image data is sequentially stored in the previous memory 14.

  The error determination unit 16 determines whether or not the plurality of tomographic image data is good based on the difference amount between the images obtained from the plurality of tomographic image data stored in the previous memory 14. For example, the fetal heart may move greatly in the image due to the movement of the fetus, mother or probe, and a good image may not be obtained. Therefore, the error determination unit 16 determines whether a good image for diagnosis is obtained. In the determination, the error determination unit 16 uses a cross-sectional difference value defined by the following equation.

  X, y, and z in Equation 1 are coordinate values on each axis in the XYZ orthogonal coordinate system of FIG. 2, and p is a pixel value corresponding to each coordinate in the tomographic image data. The difference value between two pieces of tomographic image data adjacent in the Z-axis direction is calculated by Equation (1).

  FIG. 3 is a diagram showing changes in cross-sectional difference values, and the horizontal axis of FIG. 3 shows the position of each tomographic image data. That is, the horizontal axis in FIG. 3 corresponds to the position of each scanning plane and the time at which each scanning plane is obtained, and corresponds to the Z axis in FIG. 2 (the direction of change in position over time). .

  If the fetal heart does not move significantly, the adjacent tomographic image data will be similar to each other, and the difference value obtained from Equation 1 will be relatively small. On the other hand, for example, if there is a movement of the fetus itself, the mother's breathing movement, a large displacement of the probe position, the fetal heart moves greatly in the tomographic image, and the difference value between adjacent tomographic image data is relatively large. Become. Therefore, the error determination unit 16 determines that the heart has greatly shifted in the image when the cross-sectional difference value exceeds a predetermined threshold value.

  Returning to FIG. 1, when the error determination unit 16 determines that the heart has greatly shifted, the control unit 40 controls, for example, the beamformer 12 to stop collecting tomographic image data. Note that the control unit 40 controls each unit in FIG. 1 in a concentrated manner. For example, when the error determination unit 16 determines that an error has occurred, a display or a warning indicating an error is displayed. You may display on the part 30. If the error determination unit 16 does not determine an error, a process to be described later is executed based on a plurality of tomographic image data stored in the previous memory 14.

  In the present embodiment, in addition to the collection of the above-described three-dimensional echo data (reception signal), echo data is collected from the representative portion of the target tissue over a plurality of periods related to the motion of the target tissue. . For example, when the target tissue is a fetal heart, a scan plane is formed in the vicinity of the center of the fetal heart, and within a period (for example, 1 to 2 seconds) including a plurality of heartbeats from within the scan plane. Over a period of time, echo data (reception signals) of a plurality of time phases are collected. The collected echo data is stored in the representative part memory 15. For example, after the three-dimensional echo data stored in the previous memory 14 is collected, the echo data from the representative part stored in the representative part memory 15 is collected. Of course, the echo data stored in the previous memory 14 may be collected after the echo data stored in the representative part memory 15 is collected.

  The virtual cycle setting unit 22 calculates a virtual cycle serving as a temporary cycle related to the fetal heart based on the echo data of a plurality of time phases stored in the representative part memory 15. In calculating the virtual period, the virtual period setting unit 22 uses a mutual difference value defined by the following equation.

  X and y in Equation 2 are coordinate values on each axis in the XY orthogonal coordinate system of FIG. 2, and p is a coordinate in the scanning plane (in the tomographic image) fixedly set to the representative part. The corresponding pixel value. In setting the virtual cycle by the virtual cycle setting unit 22, z in Equation 2 is time. That is, in Equation 2, one pixel value is multiplied by the difference between two pixel values between two tomographic image data corresponding to two adjacent times. As a result, the mutual difference value is relatively large when the heart expands compared to when the heart contracts, and it is possible to identify expansion and contraction that are difficult to identify with a simple difference value by the mutual difference value. .

  For example, in a certain tomographic image data z, it is assumed that the pixel p (x, y, z) is a myocardium in the vicinity of the inner wall of the heart, and the pixel value is set to p (x, y, z) = 100. When the heart expands and the heart chamber becomes larger, the pixel p (x, y, z + 1) becomes the heart chamber pixel in the tomographic image data z + 1 obtained following the tomographic image data z. Since the pixel value of the heart chamber is smaller than that of the myocardium, the pixel value is set to p (x, y, z + 1) = 10. In this example, the absolute value of the right side of Equation 2 is calculated to be 100 × (100−10) = 9000. When the heart expands, there are many pixels that change from the myocardium to the heart chamber around the inner wall of the heart, so that the mutual difference value of Equation 2 becomes relatively large.

  On the other hand, when the heart contracts, a phenomenon opposite to the above example occurs. That is, since the heart contracts and the heart chamber becomes smaller, the pixel p (x, y, z) = 10 corresponding to the heart chamber changes from the pixel p (x, y, z + 1) = 100 corresponding to the heart muscle. . In this example, when the absolute value of the right side of Equation 2 is calculated, | 10 × (10−100) | = 900, which is smaller than the value 9000 in the case of expansion. Therefore, expansion and contraction can be identified by the mutual difference value.

  FIG. 4 is a diagram illustrating a change in the mutual difference value regarding the representative site. The horizontal axis in FIG. 4 indicates the time (time) at which each tomographic image data is obtained. When the mutual difference value is calculated at each time (z) using Equation 2, the mutual difference value becomes a relatively large value when the heart expands. Therefore, the virtual cycle setting unit 22 detects the peak value (maximum value) of the mutual difference value, and determines the interval between adjacent peak values as the heart cycle (heartbeat cycle).

  However, for example, in the fetal heart, the heartbeat period may fluctuate, and when the heartbeat period fluctuates, the interval between peak values also fluctuates. Therefore, the virtual cycle setting unit 22 sets, for example, a representative (for example, second largest) interval among the peak value intervals as the virtual cycle. Note that an average value of peak value intervals may be a virtual cycle, or a most frequently used value or a centroid value obtained from a histogram of peak value intervals may be a virtual cycle.

  In setting the virtual period, M-mode measurement may be used. For example, when the target tissue is a fetal heart, an ultrasonic beam is fixedly set near the center of the fetal heart, and echoes of a plurality of time phases are generated from the ultrasonic beam over a period including a plurality of heartbeats. Data (beam data) is collected. Also in this case, the collected echo data is stored in the representative part memory 15. In the case of beam data, x in Equation 2 is a fixed value corresponding to the position of the ultrasonic beam. Then, by calculating the mutual difference value based on Equation 2 over a plurality of times (z), a periodic waveform similar to that in FIG. 4 is formed even in the case of beam data, and tomographic image data As in the case of, a typical interval among the peak value intervals, an average value of the peak value intervals, and the like are used as the virtual period.

  When the virtual period is set, the reference image search unit 24 in FIG. 1 searches for a plurality of reference images from the plurality of tomographic image data using the virtual period. Also in this search, the mutual difference value defined by Equation 2 is used.

  The reference image search unit 24 calculates the mutual difference value by applying Equation 2 to the plurality of tomographic image data stored in the previous memory 14. In the calculation of the mutual difference value by the reference image search unit 24, x, y, z in Equation 2 are coordinate values on each axis in the XYZ orthogonal coordinate system of FIG. 2, and p is each coordinate in the tomographic image data. Is a pixel value corresponding to. In this case, in Equation 2, one pixel value is multiplied by a difference between two pixel values between two tomographic image data adjacent in the Z-axis direction. As a result, the mutual difference value is relatively large when the heart expands compared to when the heart contracts, and it is possible to identify expansion and contraction that are difficult to identify with a simple difference value by the mutual difference value. .

  FIG. 5 is a diagram for explaining the search for the reference image. Each of FIGS. 5A to 5C illustrates a change in the mutual difference value calculated by the reference image search unit 24. That is, in FIG. 5, the horizontal axis indicates the position of each tomographic image data (position and time of each scanning plane), and corresponds to the Z axis of FIG. 2 (change direction of position with the passage of time). Yes. When the mutual difference value is calculated at each position (z) on the Z-axis using Equation 2, the mutual difference value becomes a relatively large value when the heart expands.

  In searching for a reference image, the reference image search unit 24 first searches a representative reference image (representative reference image) from a plurality of tomographic images. As shown in FIG. 5A, the reference image search unit 24 sets, for example, tomographic image data corresponding to a position where the mutual difference value is maximum as a representative reference image (representative reference cross section). Then, the reference image search unit 24 is separated from the plurality of tomographic images corresponding to the maximum mutual difference values by the virtual cycle set by the virtual cycle setting unit 22 (FIG. 1), with the representative reference image as a starting point. The tomographic image closest to the position is searched one after another.

  First, as shown in FIG. 5A, a tomographic image closest to a position separated from the representative reference image by a virtual period (VHR) in the positive and negative directions in the Z-axis direction is searched and used as a reference image. Next, as shown in FIG. 5B, the reference image search unit 24 searches for a tomographic image closest to a position separated from the searched reference image by a virtual period (VHR) to be a new reference image. . In FIG. 5B, broken arrows indicate the positions of a plurality of reference images (reference cross sections).

  The reference image search unit 24 searches a plurality of reference images one after another using the representative reference image as a starting point. In this way, a plurality of reference images are searched from a plurality of tomographic images corresponding to the maximum mutual difference values as shown in FIG. In FIG. 5C, dashed arrows indicate the positions of a plurality of reference images (reference cross sections).

  Returning to FIG. 1, when a plurality of reference images are searched, the reconstruction processing unit 20 divides the plurality of tomographic images into several image groups by using each of the plurality of reference images as a unit of division. . And the reconstruction process part 20 implement | achieves a reconstruction process by extracting the some tomographic image corresponding to each other periodically from each of several image groups. The reconstruction processing unit 20 reconstructs a plurality of tomographic image data stored in the previous memory 14 and stores it in the rear memory 26.

  FIG. 6 is a diagram for explaining processing by the reconstruction processing unit 20. FIG. 6 shows a correspondence relationship between data stored in the previous memory 14 and data stored in the rear memory 26. . In FIG. 6, “tomographic image Zn (n = 1, 2, 3,..., 60)” means tomographic image data at the position of the coordinate Zn on the Z axis (see FIG. 2).

  The previous memory 14 stores a plurality of tomographic image data corresponding to a plurality of scan planes formed one after another along the Z-axis direction. That is, the previous memory 14 stores a plurality of tomographic image data in the order of tomographic images Z1, tomographic images Z2,..., Tomographic images Z60,.

  The reconstruction processing unit 20 divides the plurality of tomographic image data stored in the previous memory 14 into a plurality of image groups by using each of the plurality of reference images as a unit of division. Then, a plurality of tomographic image data periodically corresponding to each other is extracted from each of the plurality of image groups.

  In FIG. 6, the tomographic image Z1, the tomographic image Z15,..., The tomographic image Z51 are a plurality of reference images searched by the reference image searching unit 24. The reconstruction processing unit 20 first extracts a tomographic image Z1, a tomographic image Z15,..., A tomographic image Z51, which are reference images, as a plurality of tomographic image data periodically corresponding to each other. The extracted tomographic image Z1, tomographic image Z15,..., And tomographic image Z51 are stored in the rear memory 26 as one data block.

  Next, the reconstruction processing unit 20 extracts a plurality of tomographic images adjacent in the positive direction in the Z-axis direction to each of the plurality of reference images as a plurality of tomographic image data periodically corresponding to each other. That is, the tomographic image Z2, the tomographic image Z16,..., And the tomographic image Z52 are extracted and stored as one data block in the rear memory 26.

  Further, the reconstruction processing unit 20 extracts a plurality of tomographic images adjacent to each of the tomographic image Z2, the tomographic image Z16,. In this way, data blocks of a plurality of tomographic images periodically corresponding to each other from each of the plurality of reference images are sequentially extracted and stored in the rear memory 26.

  Note that, according to the reconstruction process described above, there are tomographic images that are not used for the reconstruction process among a plurality of tomographic images stored in the previous memory 14. For example, the tomographic images (Z11 to Z14) between the tomographic image Z10 and the tomographic image Z15 in the previous memory 14 are tomographic images that are not used for the reconstruction process.

  In the reconstruction process described above, a plurality of data blocks are formed in the post-memory 26 after the reconstruction process. For example, the tomographic image Z1, the tomographic image Z15,..., And the tomographic image Z51 become one data block, and the tomographic image Z2, the tomographic image Z16,. The number of data blocks formed in the rear memory 26 by the reconstruction process corresponds to the number of tomographic images of the image group having the smallest number of tomographic images among the plurality of image groups divided based on the reference image. Yes. For example, when a plurality of reference images are searched as shown in FIG. 5C, the number of tomographic images in the image group corresponding to the section where the interval between two reference images adjacent to each other is the shortest is shown in FIG. As shown, the number of data blocks in the memory 26 matches.

  Therefore, for example, as shown in FIG. 5C, after a plurality of reference images are searched, the number e of tomographic images in the image group corresponding to the interval where the interval between two adjacent reference images is the shortest is confirmed. It is possible to reduce (preferably completely remove) the rebuilding process by setting the number of data blocks as e and terminating the rebuilding process when the number of data blocks reaches e as a result of the rebuilding process. become.

  In the example shown in FIG. 6, the data block corresponding to the reference image is the head of the plurality of data blocks. However, a plurality of data blocks may be formed around the data block corresponding to the reference image.

  FIG. 7 is a diagram for explaining another preferable process by the reconstruction processing unit 20. Like FIG. 6, FIG. 7 shows data stored in the front memory 14 and stored in the rear memory 26. Correspondences between data are shown.

  Also in the example illustrated in FIG. 7, the reconstruction processing unit 20 divides the plurality of tomographic image data stored in the previous memory 14 into a plurality of image groups by using each of the plurality of reference images as a unit of division. . At that time, using the number of data blocks e confirmed in advance, e / 2 tomographic images in the negative direction of the Z-axis and e / 2 in the positive direction of the Z-axis from each reference image around the position of each reference image One tomographic image is defined as one image group.

  For example, in the previous memory 14 shown in FIG. 7, e / 2 tomographic images Z14, tomographic images Z13,... In the negative direction of the Z axis centered on the tomographic image Z15 that is the reference image, and the Z axis The e / 2 tomographic images Z16, tomographic images Z17,... In the positive direction form an image group including e tomographic images centered on the tomographic image Z15. Similarly, an image group composed of e tomographic images centered on the tomographic image Z32 that is the reference image is formed, and an image group composed of e sheet tomographic images centered on the tomographic image Z51 that is the reference image. The

  In the example shown in FIG. 7 as well, a plurality of tomographic image data periodically corresponding to each other is extracted from each of the plurality of image groups. That is, the reconstruction processing unit 20 first extracts the tomographic image at the smallest position on the Z axis from each of the image groups to form one data block, and then the second smallest on the Z axis. A tomographic image at a position is extracted to form one data block. By continuing this extraction process from the smallest position to the largest position on the Z axis, a total number of e data blocks are formed in the rear memory 26.

  FIG. 7 shows three data blocks out of the total number e. That is, a data block composed of a tomographic image Z14, a tomographic image 31,..., A tomographic image 50 each preceding the reference image, and a tomographic image Z15, a tomographic image 32,. , A data block composed of a tomographic image 51, and a data block composed of a tomographic image Z16, a tomographic image 33,.

  As described above, in the example of FIG. 7, data blocks of a plurality of tomographic images periodically corresponding to each other around each of the plurality of reference images are sequentially extracted and stored in the rear memory 26.

  In the example shown in FIG. 7, e / 2 tomographic images in the negative direction of the Z axis and e / 2 tomographic images in the positive direction of the Z axis from each reference image with the position of each reference image as the center. Although one image group is provided, one image group may be formed by shifting the position of each reference image from the center. That is, one image group may be formed by adding different numbers of tomographic images before and after each reference image. In this case, the data block corresponding to the reference image is shifted from the center of all the data blocks in the rear memory 26.

  Returning to FIG. 1, the three-dimensional image forming unit 28 forms three-dimensional image data that three-dimensionally displays the fetal heart based on a plurality of reconstructed tomographic image data stored in the post-memory 26. The three-dimensional image forming unit 28 forms three-dimensional image data for each time phase based on one data block stored in the post-memory 26. For example, three-dimensional image data of time phase T1 is formed based on the tomographic image Z1, tomographic image Z15,..., Tomographic image Z51 stored in the post-memory 26 shown in FIG. ,..., Three-dimensional image data of time phase T2 is formed based on the tomographic image Z52. Alternatively, the three-dimensional image data of the time phases T1 to Te is formed by forming the three-dimensional image data of each time phase based on each of the total number of e data blocks formed in the post-memory 26 shown in FIG. Is formed. In the reconstruction process described with reference to FIG. 7, three-dimensional image data corresponding to a reference image serving as a temporal reference of a periodic motion such as a heartbeat is a three-dimensional image from time phases T1 to Te. Placed in the center of the data. That is, it becomes possible to arrange the three-dimensional image data based on the reference image that is considered to have the most coincident temporal relationship with each other at the center of the time phases T1 to Te.

  The three-dimensional image forming unit 28 applies various methods such as a volume rendering method, an integration method, and a projection method to form three-dimensional image data over a plurality of time phases for each time phase. Thus, an image corresponding to the three-dimensional image data formed over a plurality of time phases is displayed on the display unit 30, and a pseudo real-time three-dimensional moving image is displayed. For example, an image corresponding to three-dimensional image data from the time phase T1 to the final time phase Te may be repeatedly displayed and loop reproduction may be executed.

  According to the above-described embodiment, even when a fetal heart or the like whose heartbeat cycle is unstable is to be diagnosed, an appropriate reference image is searched according to the cycle variation and the data block is reconstructed. The disturbance of the image due to the fluctuation of the period is reduced (desirably completely removed), and a display image with high reliability can be obtained. In particular, when determining the virtual period, since the echo data collected from the representative part of the target tissue, that is, from a fixed position is used, the virtual period is set from the echo data collected in a mobile manner Compared to, the accuracy of setting the virtual period is improved.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above is only a mere illustration in all the points, and does not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof. For example, in the above-described embodiment, a low-speed scan is performed in which a plurality of scan planes are formed while slowly moving the scan plane along the Z-axis direction, and echo data is collected from within a three-dimensional space. Prior to this low-speed scanning, the probe position designation may be supported by performing a high-speed scan on a trial basis in about two seconds for a round trip.

  10 probe, 12 beam former, 16 error determination unit, 20 reconstruction processing unit, 22 virtual cycle setting unit, 24 reference image search unit, 28 three-dimensional image formation unit.

Claims (9)

A probe for transmitting and receiving ultrasonic waves in a three-dimensional space including a target tissue that moves periodically;
By controlling the probe, received signals are collected from representative regions of the target tissue over a plurality of periods of the movement, and further, the scanning plane is moved over the plurality of periods of the movement while moving within the three-dimensional space. A transmission / reception control unit for forming a plurality of scanning planes;
A virtual period setting unit that sets a virtual period of motion related to the target tissue based on the received signal collected from the representative site;
A reference image search unit that searches a plurality of reference images at intervals corresponding to the virtual period from a plurality of images corresponding to the plurality of scanning planes;
Image reconstruction that divides the plurality of images into a plurality of image groups by extracting each of the plurality of reference images as a unit of division, and extracts a plurality of images periodically corresponding to each of the plurality of image groups And
A display image forming unit that forms a display image of the target tissue based on a plurality of images periodically corresponding to each other;
Having
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The virtual cycle setting unit calculates a feature value reflecting a change in the received signal between time phases based on the received signals of a plurality of time phases collected from the representative part, and based on the feature amount, the virtual cycle setting unit To decide,
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 2,
The virtual cycle setting unit calculates a mutual difference value for each time phase as the feature amount, and determines the virtual cycle based on a temporal change of the mutual difference value obtained over a plurality of time phases.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 3.
The virtual cycle setting unit determines the virtual cycle based on a time phase interval corresponding to a maximum value of a mutual difference value obtained over a plurality of time phases.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 4,
The virtual cycle setting unit uses reception signals of a plurality of time phases collected one-dimensionally from an ultrasonic beam set in the representative part,
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 4,
The virtual cycle setting unit uses reception signals of a plurality of time phases that are two-dimensionally collected from the scanning plane set in the representative part.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6,
The transmission / reception control unit forms a plurality of scanning planes in the three-dimensional space after collecting reception signals from the representative part.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to any one of claims 1 to 6,
The transmission / reception control unit collects reception signals from the representative part after forming a plurality of scanning planes in the three-dimensional space,
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to any one of claims 1 to 8,
The reference image search unit, based on a mutual difference value corresponding to each of the plurality of images, uses one image corresponding to the maximum mutual difference value as a representative reference image, and starts from the representative reference image as a starting point. From the plurality of images corresponding to the mutual difference value, the image closest to the position separated by the virtual period is searched one after another, and the plurality of reference images are used.
An ultrasonic diagnostic apparatus.

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