JP4755514B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that forms an ultrasonic image of a subject using a region of interest.

  There is known an ultrasonic diagnostic apparatus that forms a volume rendering image as an ultrasonic image that three-dimensionally represents a subject (see Patent Document 1). In this method, a predetermined voxel operation is sequentially performed on individual echo data (voxel data) existing on each perspective line (ray), and a result of the voxel operation is calculated for each perspective line. A three-dimensional image (volume rendering image) is formed as a set of result values of the voxel operation regarding the line. The volume rendering image formed in this way greatly contributes to the diagnosis of, for example, a fetus.

  The fetus is in amniotic fluid with a relatively low echo value. In the volume rendering method, a voxel having a small echo value is not easily reflected in the result of the voxel calculation. Therefore, the echo obtained from the fetus is strongly reflected in the volume rendering image.

  However, there are skin, fat layer, muscle, uterus, and placenta in the abdomen of the pregnant woman between the ultrasound probe that transmits and receives ultrasound and the fetus. It will be reflected in the image. Therefore, a region of interest (ROI) is used to clearly display the fetus. Some techniques related to the region of interest have been proposed (Patent Document 2, etc.).

  By setting a region of interest in the echo data space obtained three-dimensionally and forming a volume rendering image based on the echo data in the region of interest, it is possible to obtain an image that clearly displays the fetus. . For example, by setting the region of interest to remove the skin, fat layer, muscle, uterus, placenta, etc. of the pregnant woman's abdomen, and setting the region of interest to include only the fetuses present in the amniotic fluid and amniotic fluid, the fetus It is possible to form a volume rendering image in which the image is clearly displayed.

Japanese Patent No. 2883584 JP 2005-288153 A

  The region of interest intended for the fetus is set, for example, by a user adjusting the position and size of a trapezoidal region set in advance as a suitable shape along the uterine wall. However, even if the region of interest is set with high precision, if the fetus moves after the region of interest is set, the fetus may protrude from the region of interest.

  If a volume rendering image is formed from echo data in a region of interest while the fetus protrudes from the region of interest, an image of the fetus lacking the protruding portion is formed. In addition, resetting the region of interest every time the fetus moves to avoid protrusions complicates the user operation.

  In such a situation, the inventors of the present application have conducted research on a technique for preventing a lack of an image of a fetus or the like without complicating a user operation for setting a region of interest.

  The present invention has been made in such a background, and an object of the present invention is to provide a technique for capturing a subject portion protruding from a region of interest in an ultrasonic image.

  In order to achieve the above object, an ultrasonic diagnostic apparatus according to a preferred aspect of the present invention includes: a transmission / reception unit that acquires echo data by transmitting / receiving ultrasonic waves in a three-dimensional space including a subject; The echo data of the portion of the subject that protrudes from the region of interest is identified based on the region of interest that is set to surround the subject in the echo data space that is composed of the echo data that has been recorded and the echo data in the echo data space A protruding portion identifying means, an image forming means for forming an ultrasonic image of the subject based on the echo data in the region of interest and the echo data of the subject portion protruding from the region of interest, and the formed ultrasonic image Display means for displaying.

  In the above configuration, the echo data of the subject portion that protrudes from the region of interest is identified by the protruding portion identifying means. For this reason, the image forming means can form an image of the subject portion using echo data of the subject portion that protrudes from the region of interest. That is, the subject portion that protrudes from the region of interest can be captured in the ultrasound image. Thereby, for example, even when the fetus protrudes from the region of interest, the lack of an image corresponding to the protruding portion is prevented.

  In a preferred aspect, the protruding portion identification means includes a binarization processing unit that performs binarization processing on the echo data in the echo data space to extract echo data of the high luminance portion, and echo data of the high luminance portion. A subject extraction unit that performs labeling on the subject and extracts echo data corresponding to the subject, and a missing portion that extracts the echo data of the subject portion that protrudes from the region of interest out of the echo data corresponding to the subject The image forming means forms an ultrasound image of the subject based on the echo data of the subject portion extracted by the lacking portion extraction portion and the echo data in the region of interest, It is characterized by that.

  In a desirable mode, the subject is a fetus in a mother body, and the binarization processing unit performs binarization processing on the echo data in the echo data space to obtain echo data other than the amniotic fluid echo data and amniotic fluid. By discriminating from the echo data, the echo data other than the amniotic fluid is extracted as the echo data of the high-luminance portion, and the subject extraction unit removes the suspended matter in the amniotic fluid from the echo data other than the amniotic fluid by a labeling process. By removing the echo data corresponding to the fetus that is the subject, the missing portion extraction unit extracts the echo data of the fetus portion that protrudes from the region of interest out of the echo data corresponding to the fetus, The image forming means is configured to detect the fetal ultrasound based on the echo data of the fetus part extracted by the missing part extraction unit and the echo data in the region of interest. Forming an image, characterized in that.

  In a preferred aspect, the image forming unit forms a volume rendering image as the ultrasonic image.

  According to the present invention, it is possible to capture a subject portion that protrudes from a region of interest into an ultrasonic image. Thereby, for example, even when the fetus protrudes from the region of interest, the lack of an image corresponding to the protruding portion is prevented.

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

  FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a functional block diagram showing the overall configuration thereof. The ultrasonic diagnostic apparatus according to the present invention forms an ultrasonic image of a subject based on echo data obtained from the subject. The subject to be diagnosed is, for example, a tissue in a living body or a fetus in a mother body. Therefore, in the present embodiment, the fetus in the mother body will be described as a diagnosis target. However, the diagnostic object of the ultrasonic diagnostic apparatus according to the present invention is not limited to the fetus.

  The ultrasonic probe 10 is an ultrasonic probe that transmits and receives ultrasonic waves to and from a fetus in the mother's body. The ultrasonic probe 10 includes a plurality of vibration elements (not shown), and forms an ultrasonic beam in a three-dimensional space. Multiple vibration elements are controlled electronically or mechanically, and reflected waves (echoes) are acquired from the entire area of the three-dimensional space (in the scanning space) by scanning the ultrasonic beam in the three-dimensional space. To do.

  The transmission / reception unit 12 controls a plurality of vibration elements in the ultrasonic probe 10 to form a transmission beam, and scans it in a three-dimensional space. Further, a plurality of received signals obtained from a plurality of vibration elements are phased and added to form a reception beam, and echo data is acquired from the entire scanning space. Thus, the transmission / reception unit 12 has functions of a transmission beamformer and a reception beamformer.

  The three-dimensional data memory 14 is a memory that stores echo data supplied from the transmission / reception unit 12. In the three-dimensional data memory 14, a plurality of echo data (voxel data obtained from a plurality of voxels) obtained from the entire area in the three-dimensional space are stored at addresses corresponding to the positions of the respective echo data (voxel positions). . For example, a three-dimensional space is represented by an xyz orthogonal coordinate system, and an echo value (luminance value) at each position is stored at an address corresponding to the coordinate value at that position. Incidentally, when an address is designated by the read control unit 34, echo data of the designated address is output to each processing unit in the subsequent stage.

  The echo data stored in the three-dimensional data memory 14 is supplied to the image forming unit 30 via the gate 28. There is also a path that is directly supplied to the image forming unit 30 without going through the gate 28. Further, the echo data stored in the three-dimensional data memory 14 is subjected to various data processing from the binarization processing unit 16 to the synthesis unit 26.

  FIG. 2 and FIG. 3 are diagrams for explaining data processing executed from the binarization processing unit 16 to the synthesis unit 26. 2 and 3 are schematic views of images formed from echo data for each processing stage. The schematic diagrams of the images shown in FIGS. 2 and 3 show the state of the echo data in the three-dimensional data space, and these images may not be displayed on the monitor 32. Of course, a configuration in which these images are displayed on the monitor 32 is also possible.

  2 and 3 are schematic diagrams based on a two-dimensional image for convenience of illustration, but actual echo data handled in the present embodiment is obtained from the entire region in the three-dimensional space and is tertiary. The former data space is formed as described above. Hereinafter, the functions from the binarization processing unit 16 to the synthesis unit 26 of FIG. 1 will be described with reference to FIGS. 2 and 3 together.

  FIG. 2A is a schematic diagram of an image corresponding to the original data. That is, FIG. 2A corresponds to an image formed from echo data stored in the three-dimensional data memory 14 and schematically shows the fetus 50 floating in the amniotic fluid 54 in the uterus 52.

  The binarization processing unit 16 performs binarization processing on the original data corresponding to FIG. That is, the binarization processing unit 16 performs binarization processing on the echo data stored in the three-dimensional data memory 14. The binarization processing unit 16 compares a predetermined threshold value with an echo value of each echo data, and converts a plurality of echo data in the three-dimensional data space into an echo data having a large echo value (luminance value) and an echo value. Sort into small echo data. The threshold value is set to a size that separates the amniotic fluid from other parts. Thereby, a plurality of echo data obtained from the entire area in the three-dimensional space is separated into echo data corresponding to amniotic fluid and echo data other than amniotic fluid.

  The threshold value used for the binarization process may use a value that is preset in the apparatus in advance, or may be automatically set by the apparatus based on echo values of a plurality of echo data. May be set by the user.

  FIG. 2B is a schematic diagram of an image corresponding to data after binarization processing. As shown in FIG. 2B, the binarization process separates the echo data corresponding to the amniotic fluid 54 and the other part of the echo data. The other part includes a tissue part having a larger echo value than that of the amniotic fluid 54. In other words, the other parts are constituted by the fetus 50, the uterus 52, the suspended matter 56 floating in the amniotic fluid 54, and the like.

  The fetus extraction unit 18 extracts a portion corresponding to the fetus 50 from the image of FIG. A labeling process is used for the extraction process. That is, a plurality of pieces of echo data other than the amniotic fluid (high-intensity portion) extracted by the binarization process are separated into echo data blocks that are spatially connected in the three-dimensional data space. As a result, the echo data of the high-intensity portion in the three-dimensional data space is separated into a plurality of isolated echo groups in units of isolated echo groups that are composed of contiguous chunks of echo data.

  A labeling number is assigned to each of the plurality of isolated echo groups. For example, in the image of FIG. 2B, the labeling number “1” is assigned to the isolated echo group composed of the fetus 50 and the uterus 52, and the labeling numbers “2” and “3” are assigned to each of the two floating objects 56. Is given. The fetal extraction unit 18 selects the fetus 50 from among a plurality of isolated echo groups assigned with labeling numbers.

  That is, a lump of isolated echoes composed of the fetus 50 and the uterus 52 are selected from the image of FIG. For example, the fetal extraction unit 18 may determine an isolated echo group including the fetus 50 and the uterus 52 according to a user's selection operation, or assuming that the fetus 50 is located near the center of the image. An isolated echo group including echo data at the center of the image may be selected. Further, the isolated voxel group having the largest volume value among the isolated voxel groups may be regarded as an isolated echo group including the fetus 50 and the uterus 52.

  Further, the fetal extraction unit 18 leaves the isolated echo group composed of the fetus 50 and the uterus 52 and removes the other isolated echo group as a noise component. Thereby, as shown in FIG. 2C, only the isolated echo group composed of the fetus 50 and the uterus 52 remains.

  In FIG. 2B, since the fetus 50 and the uterus 52 are in contact with each other, the fetus 50 and the uterus 52 are extracted as a group of isolated echoes. On the other hand, if the fetus 50 and the uterus 52 are not in contact, the fetus 50 and the uterus 52 are extracted as independent isolated echo groups. In this case, the fetus extraction unit 18 selects an isolated echo group of the fetus 50. Therefore, in that case, only the isolated echo group of the fetus 50 is left.

  Data obtained by extracting the fetus 50 by the fetal extraction unit 18, that is, a plurality of echo data corresponding to the schematic diagram of FIG. 2C, is supplied to the two gates 20 and 22, and the data in the region of interest and the interest Sorted into data outside the area.

  The region of interest is set by the region of interest setting unit 36, and is used when the volume rendering image is formed in the image forming unit 30 described later. The region of interest is set so as to surround the fetus 50 as the subject in the echo data space. It is desirable to use an image displayed on the monitor 32 for setting the region of interest.

  That is, the echo data (original data) stored in the three-dimensional data memory 14 is also directly supplied to the image forming unit 30, and the image forming unit 30 stores the echo data stored in the three-dimensional data memory 14. From, for example, an orthogonal three-section image is formed and displayed on the monitor 32. Then, the user sets the region of interest so as to surround the fetus 50 while viewing the orthogonal three-section image displayed on the monitor 32. For example, as a suitable shape along the uterine wall, the region of interest is set by the user adjusting the position and size of a preset trapezoidal region, a rectangular region, a sectoral trapezoidal region combining trapezoids and sectors, etc. Is done.

  When the region of interest is set, address information of the region of interest in the three-dimensional data space is supplied from the region of interest setting unit 36 to the read control unit 34. Further, the region-of-interest address information is supplied to the gate 20 as the region-of-interest address information from the read control unit 34, and the region-of-interest address information is supplied to the gate 22.

  Based on the address information in the region of interest, the gate 20 extracts echo data existing inside the region of interest from among a plurality of echo data corresponding to the schematic diagram of FIG. The extraction result is shown in FIG. On the other hand, the gate 22 extracts the echo data existing outside the region of interest from the plurality of echo data corresponding to the schematic diagram of FIG. The extraction result is shown in FIG.

  FIG. 3D schematically shows echo data in the region of interest 60, while FIG. 3E schematically shows echo data outside the region of interest 60. In these drawings, the region of interest 60 indicated by a broken line is rectangular, but the region of interest 60 may be formed based on a trapezoid or the like. Note that the region of interest 60 is formed three-dimensionally in the three-dimensional data space.

  Since the region of interest 60 is set so as to surround the fetus 50, most of the echo data of the fetus 50 is within the region of interest 60. However, if the fetus 50 is completely stored in the region of interest 60, the setting operation of the region of interest 60 may be complicated, and even if the fetus 50 is completely stored in the region of interest 60, May move out of the region of interest 60. That is, as shown in FIG. 3E, the fetal portion 50 ′ (for example, part of the forehead 50) may protrude from the region of interest 60. In the present embodiment, echo data of the fetus portion 50 ′ protruding from the region of interest 60 is used and captured in the ultrasound image by the processing described below.

  The missing part determination unit 24 extracts the echo data of the fetus part 50 ′ from the echo data outside the region of interest 60. For example, the missing portion determination unit 24 performs labeling processing on echo data outside the region of interest 60 illustrated in FIG. 3E and separates it into a plurality of isolated echo groups. An isolated echo group having a volume value smaller than a predetermined value is extracted from among them, and the extracted isolated echo group is regarded as a fetal portion 50 '.

  In other words, as shown in FIG. 3E, most of the echo data existing outside the region of interest 60 is echo data corresponding to the uterus 52, and therefore, the uterus 52 in the isolated echo group obtained by the labeling process. The solitary echo group corresponding to is a very large volume value. On the other hand, the volume value of the isolated echo group corresponding to the fetal portion 50 'is very small. That is, there is a large difference in volume value between the isolated echo group of the uterus 52 and the isolated echo group of the fetal part 50 ', and the uterus 52 and the fetal part 50' are discriminated based on the volume value by a predetermined threshold value. can do. The threshold value may be changed by the user as necessary. Alternatively, the user may specify the fetal portion 50 ′ using an image displayed on the monitor 32 from among a plurality of isolated echo groups obtained by the labeling process.

  When the missing portion determination unit 24 extracts the echo data of the fetal portion 50 ', the combining unit 26 combines the echo data of the fetal portion 50' with the echo data in the region of interest. That is, the echo data of the fetal portion 50 'shown in FIG. 3 (F) is synthesized with the echo data in the region of interest shown in FIG. 3 (D) to form echo data shown in FIG. 3 (G). .

  FIG. 3G schematically shows echo data after the synthesizing process by the synthesizing unit 26, and the fetal portion 50 ′ protruding from the region of interest 60 is synthesized with the echo data in the region of interest 60. Indicates the state. As a result of the synthesis of the fetal portion 50 ′, the echo data corresponding to the fetus 50 is extracted without loss in FIG.

  The synthesizer 26 supplies the gate 28 with the address information of the echo data in the region of interest and the echo data of the fetal portion 50 ′ protruding from the region of interest. The gate 28 outputs the echo data in the region of interest and the echo data of the fetal portion 50 ′ to the image forming unit 30 among the plurality of echo data (original data) stored in the three-dimensional data memory 14. Then, the image forming unit 30 forms a volume rendering image based on the echo data output from the gate 28. The formed volume rendering image is displayed on the monitor 32.

  A well-known method is used for forming the volume rendering image. For example, the technique described in Japanese Patent No. 2883584 is suitable. The outline of the processing is as follows.

  First, a viewpoint is virtually set outside the three-dimensional data space, and a screen as a two-dimensional plane is virtually set on the opposite side of the viewpoint through the three-dimensional data space. A plurality of rays (perspective lines) are defined from the viewpoint side. The ray extends through the 3D data space to the screen. Therefore, an echo data string composed of a plurality of echo data (voxel data) corresponds to a ray. When the voxel operation based on the volume rendering method is sequentially executed for each echo data from the viewpoint side along the ray, the pixel value is determined as a result of the final voxel operation. The pixel value is mapped to the coordinates corresponding to the ray on the virtually set screen. In this way, the voxel operation is performed on each of the plurality of rays, and the pixel value obtained for each ray is mapped on the screen, whereby a volume rendering image is formed on the screen.

  FIG. 4 shows a volume rendering image of the fetus. FIG. 4A is an image formed only by echo data in the region of interest with the fetus protruding from the region of interest. The image shown in FIG. 4A is formed based only on echo data in the region of interest, with the forehead portion protruding from the region of interest. That is, as shown in the schematic diagram of FIG. 2 (reference), only the echo data in the region of interest is extracted from the original data, and is formed by echo data in a state where the forehead protrudes from the region of interest and is missing. Therefore, in FIG. 4A, the volume rendering image lacks the forehead portion of the fetus.

  On the other hand, FIG. 4B shows an image formed by the present embodiment, which is formed by echo data in the region of interest and echo data of the fetus portion protruding from the region of interest when the fetus protrudes from the region of interest. It is an image. That is, as shown in the schematic diagram of FIG. 3G, since the fetal portion 50 ′ protruding from the region of interest is synthesized (added) to the echo data in the region of interest, in FIG. A volume rendering image of the fetus is formed without any loss of the forehead.

  Thus, in the present embodiment, a volume rendering image can be formed by capturing a fetus portion that protrudes from the region of interest. Therefore, even when the fetus protrudes from the region of interest, the lack of an image corresponding to the protruding portion is prevented.

  When the echo data in the three-dimensional data memory 14 is updated for each time phase and a volume rendering image is formed for each time phase by the image forming unit 30 accordingly, the binarization processing unit 16 Therefore, it is desirable that the processing in the synthesis unit 26 is executed for each time phase, and the fetal portion that protrudes from the region of interest is extracted for each time phase. As a result, even when the fetus moves and changes occur in the portion that protrudes from the region of interest, the protruding portion is extracted so as to follow the change. As a result, the volume rendering image can be formed by capturing the fetal portion for each time phase according to the protruding state at that time.

  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.

1 is a functional block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present invention. It is a figure for demonstrating the data processing performed in this embodiment. It is a figure for demonstrating the data processing performed in this embodiment. It is a figure which shows the volume rendering image of a fetus.

Explanation of symbols

  14 three-dimensional data memory, 16 binarization processing unit, 18 fetal extraction unit, 24 missing part determination unit, 26 synthesis unit, 30 image forming unit.

Claims (4)

A transmitting / receiving means for acquiring echo data by transmitting / receiving ultrasonic waves in a three-dimensional space including the subject;
Based on the region of interest set to surround the subject in the echo data space composed of the acquired echo data and the echo data in the echo data space, the echo data of the subject portion that protrudes from the region of interest A protruding portion identifying means for identifying;
An image forming means for forming an ultrasonic image of the subject based on the echo data in the region of interest and the echo data of the subject portion protruding from the region of interest;
Display means for displaying the formed ultrasonic image;
Having
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The protruding portion identifying means is
A binarization processing unit that performs binarization processing on echo data in the echo data space and extracts echo data of a high-luminance portion;
A subject extraction unit that performs a labeling process on the echo data of the high-luminance portion and extracts echo data corresponding to the subject;
A missing portion extraction unit that extracts echo data of a subject portion that protrudes from the region of interest out of echo data corresponding to the subject; and
Including
The image forming unit forms an ultrasonic image of the subject based on the echo data of the subject portion extracted by the lacking portion extraction unit and the echo data in the region of interest;
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 2,
The subject is a fetus in the mother's body,
The binarization processing unit performs binarization processing on the echo data in the echo data space and discriminates the echo data of the amniotic fluid portion from the echo data other than the amniotic fluid, so that the echo data of the high luminance portion Echo data other than amniotic fluid is extracted as
The subject extraction unit extracts the echo data corresponding to the fetus being the subject by removing the suspended matter in the amniotic fluid from the echo data other than the amniotic fluid by the labeling process,
The missing portion extraction unit extracts echo data of a fetus portion that protrudes from the region of interest among echo data corresponding to a fetus,
The image forming means forms an ultrasound image of the fetus based on the echo data of the fetal part extracted by the missing part extraction unit and the echo data in the region of interest.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 3.
The image forming unit forms a volume rendering image as the ultrasonic image;
An ultrasonic diagnostic apparatus.