JPWO2011129237A1 - Ultrasonic diagnostic equipment - Google Patents

Abstract

An ultrasonic diagnostic apparatus that calculates a ratio of elasticity information based on elasticity information obtained in a region of interest set in an image area of a reference deformable body and elasticity information obtained in a region of interest set in an image area of a target region To provide the elasticity at the tomographic site based on the ultrasonic probe 12 and the strain or elastic modulus at the tomographic site based on the RF signal frame data of the tomographic site of the subject 10 via the ultrasound probe 12 In an ultrasonic diagnostic apparatus comprising an elastic image construction unit 34 for generating an image and a display unit 26 for displaying an elastic image, an image of a reference deformable body 50 installed on an ultrasonic transmission / reception surface of the ultrasonic probe 12 Based on the region of interest setting unit 38 that sets the first region of interest in the region and the second region of interest in the image region of the biological tissue of the subject 10, and the elasticity information of the first region of interest and the second region of interest A calculation unit 32 for calculating a ratio of elasticity information Obtain.

Description

  The present invention relates to an ultrasonic diagnostic apparatus for displaying a tomographic image and an elastic image showing the hardness or softness of a living tissue for an imaging target site in a subject using ultrasonic waves.

  The ultrasonic diagnostic apparatus transmits an ultrasonic wave into the subject using an ultrasonic probe, receives an ultrasonic reflected echo signal corresponding to the structure of the living tissue from the inside of the subject, and constructs a tomographic image, for example. Display for diagnosis.

  An index based on the normalized index value by normalizing the physical quantity correlated with the hardness such as strain at the plurality of measurement points of the tomographic region based on the physical quantity correlated with the hardness such as the distortion of the reference region of the subject. Displaying a modified elastic image is performed (for example, Patent Document 1). According to Patent Document 1, it is possible to set a reference area in the image area of the reference deformable body and generate and display an indexed elasticity image.

International Publication WO2006 / 121031 Publication

  Patent Document 1 discloses that a reference area is set in the image area of the reference deformable body and an indexed elasticity image is generated and displayed. However, the image area of the reference deformable body is set as the reference area. The calculation of the ratio of elasticity information based on the elasticity information obtained in the reference region and the elasticity information obtained in the region of interest set in the region of interest is not disclosed. Therefore, it is possible to calculate the ratio of elasticity information based on the elasticity information obtained in the region of interest set in the image area of the reference deformable body and the elasticity information obtained in the region of interest set in the image area of the target region. I couldn't.

  Therefore, in the present invention, the ratio of elasticity information is calculated based on the elasticity information obtained in the region of interest set in the image area of the reference deformable body and the elasticity information obtained in the region of interest set in the image area of the target region. The purpose is to do.

  In order to achieve the object of the present invention, an ultrasonic probe and a tomographic site based on the distortion or elastic modulus of the tomographic site based on the RF signal frame data of the tomographic site of the subject via the ultrasonic probe In an ultrasonic diagnostic apparatus including an elastic image configuration unit that generates an elastic image and a display unit that displays an elastic image, a first deformation is provided in an image region of a reference deformable body installed on an ultrasonic transmission / reception surface of the ultrasonic probe. 1 The region of interest is set, and the region of interest setting unit that sets the region of interest in the image region of the biological tissue of the subject, and the elasticity information ratio based on the elasticity information of the region of interest 1 and the region of interest 2 And a calculation unit for calculating. Therefore, it is possible to calculate the ratio of elasticity information based on the elasticity information obtained in the region of interest set in the image region of the reference deformable body and the elasticity information obtained in the region of interest set in the image region of the site of interest. .

  The region-of-interest setting unit sets the first region of interest and the second region of interest based on the acoustic properties of the reference deformable body and the biological tissue of the subject, or the distortion in the image region of the biological tissue of the subject is the most. Set the second region of interest in a small region, set the first region of interest at the depth in the scan direction and below the thickness of the reference deformable body, or match the position of the second region of interest You can set the area.

  Further, the calculation unit can correct the ratio of the elasticity information according to the depth of the first region of interest and the second region of interest.

  According to the present invention, the ratio of elasticity information is calculated based on the elasticity information obtained in the region of interest set in the image area of the reference deformable body and the elasticity information obtained in the region of interest set in the image area of the target region. can do.

The block diagram which shows the structure of the ultrasonic diagnosing device of this invention The block diagram which shows the elasticity information calculating part 32 of this invention The figure which shows Example 1 of this invention The figure which shows Example 2 of this invention The figure which shows Example 3 of this invention The figure which shows Example 2 of this invention The figure which shows Example 2 of this invention The figure which shows Example 3 of this invention

  An ultrasonic diagnostic apparatus to which the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus 1 to which the present invention is applied. As shown in FIG. 1, the ultrasound diagnostic apparatus 1 includes an ultrasound probe 12 that is used in contact with the subject 10 and a time interval between the subject 10 via the ultrasound probe 12. A transmission unit 14 that repeatedly transmits ultrasonic waves, a reception unit 16 that receives ultrasonic waves reflected from the subject 10 as reflected echo signals, an ultrasonic transmission / reception control unit 17 that controls the transmission unit 14 and the reception unit 16, A phasing addition unit 18 that performs phasing addition of the reflected echo received by the reception unit 16 is provided. A reference deformable body 50 is provided on the ultrasonic transmission / reception surface of the ultrasonic probe 12. That is, when imaging the subject 10, the reference deformable body 50 is disposed between the ultrasound probe 12 and the subject 10.

  Further, based on the RF signal frame data from the phasing addition unit 18, the tomographic image forming unit 20 that forms a gray tomographic image of the subject 10, for example, a black and white tomographic image, and the output signal of the tomographic image forming unit 20 are displayed on the image display unit 26. And a black-and-white scan converter 22 for conversion to suit the display.

  Also, the RF signal frame data output from the phasing adder 18 is stored, the RF signal frame data selector 28 for selecting at least two pieces of frame data, and the displacement measurement for measuring the displacement of the biological tissue of the subject 10 The elastic information calculating unit 32 for obtaining elastic information of strain or elastic modulus from the displacement measured by the displacement measuring unit 30; and forming a color elastic image from the strain or elastic modulus calculated by the elastic information calculating unit 32. An elastic image construction unit 34 and a color scan converter 36 that converts the output signal of the elastic image construction unit 34 to match the display of the image display unit 26 are provided. Then, a switching addition unit 24 that superimposes the tomographic image and the elasticity image or displays them in parallel or performs switching, and an image display unit 26 that displays the image output from the switching addition unit 24 are provided.

  Further, the region of interest is set for the image displayed on the image display unit 26, and the region of interest setting unit 38 for transmitting the position information of the set region of interest to the elastic information calculation unit 32 and the image display unit 26, and the region of interest The setting unit 38 is provided with an operation unit 40 for instructing setting of a region of interest.

  Here, the ultrasonic diagnostic apparatus 1 will be described in detail. The ultrasonic probe 12 is formed by arranging a plurality of transducers, and has a function of transmitting and receiving ultrasonic waves to and from the subject 10 via the transducers. The reference deformable body 50 provided on the ultrasonic transmission / reception surface of the ultrasonic probe 12 has acoustic characteristics that are relatively close to the acoustic characteristics (sound speed, acoustic impedance, etc.) of the living tissue of the subject 10. The different acoustic characteristics are, for example, that the attenuation rate of the reference deformable body 50 is lower than the attenuation rate of the biological tissue of the subject 10, and the reference deformable body 50 is configured uniformly by a predetermined material. It is more uniform than tissues (including complex organs). The reference deformable body 50 is generated based on an oil-based gel material, a water-based gel material such as acrylamide, or silicon.

  The transmission unit 14 generates a transmission pulse for generating an ultrasonic wave by driving the ultrasonic probe 12, and has a function of setting a convergence point of the transmitted ultrasonic wave to a certain depth. Yes. The receiving unit 16 amplifies the reflected echo signal based on the ultrasonic wave received by the ultrasonic probe 12 with a predetermined gain to generate an RF signal, that is, a received signal. The phasing / adding unit 18 receives the RF signal amplified by the receiving unit 16 and performs phase control, and forms an ultrasonic beam at one or a plurality of convergence points to generate RF signal frame data.

  The tomographic image construction unit 20 receives the RF signal frame data from the phasing addition unit 18 and performs signal processing such as gain correction, log compression, detection, contour enhancement, and filter processing to obtain tomographic image data. . The monochrome scan converter 22 includes an A / D converter that converts tomographic image data from the tomographic image construction unit 20 into a digital signal, a frame memory that stores a plurality of converted tomographic image data in time series, and a control It is configured to include a controller. This black and white scan converter 22 acquires tomographic frame data in the subject 10 stored in the frame memory as one image, and reads out the acquired framed frame data in synchronization with the television.

  The RF signal frame data selection unit 28 stores the plurality of RF signal frame data from the phasing addition unit 18, and selects one set, that is, two RF signal frame data from the stored RF signal frame data group. For example, the RF signal frame data generated from the phasing adder 16 based on the time series, that is, the image frame rate, is sequentially stored in the RF signal frame data selector 28, and the stored RF signal frame data (N) is One RF signal frame data (X) from among the RF signal frame data group (N-1, N-2, N-3 ... NM) stored in the past in time at the same time as selecting as one data Select. Here, N, M, and X are index numbers assigned to the RF signal frame data, and are natural numbers.

  Then, the displacement measuring unit 30 performs one-dimensional or two-dimensional correlation processing on the selected set of RF signal frame data (N) and RF signal frame data (X) to correspond to each point of the tomographic image. A one-dimensional or two-dimensional displacement distribution related to the displacement or movement vector in a biological tissue, that is, the direction and magnitude of the displacement is obtained. Here, a block matching method is used to detect the movement vector. The block matching method divides an image into blocks consisting of N × N pixels, for example, focuses on the block in the region of interest, searches the previous frame for the block that most closely matches the block of interest, and refers to this Then, predictive encoding, that is, processing for determining the sample value by the difference is performed.

  The elasticity information calculation unit 32 calculates a biological tissue corresponding to each point on the tomographic image from the measurement value output from the displacement measurement unit 30, for example, the displacement and the pressure value output from the pressure measurement unit (not shown). The strain or elastic modulus is calculated, and an image signal for elastic image, that is, elastic image data is generated based on the strain or elastic modulus. The pressure measurement unit can also measure the pressure value from the degree of deformation of the reference deformable body 50 that has been deformed by pressing the subject 10.

  At this time, the strain data is calculated by spatially differentiating, for example, the displacement of the living tissue. The elastic modulus data is calculated by dividing the change in pressure by the change in strain. For example, assuming that the displacement measured by the displacement measuring unit 30 is L (X) and the pressure measured by the pressure measuring unit 46 is P (X), the strain ΔS (X) is a spatial differentiation of L (X). Therefore, it can be calculated using the equation ΔS (X) = ΔL (X) / ΔX. Further, the Young's modulus Ym (X) of the elastic modulus data is calculated by the equation Ym = (ΔP (X)) / ΔS (X). Since the Young's modulus Ym determines the elastic modulus of the living tissue corresponding to each point of the tomographic image, two-dimensional elastic image data can be obtained continuously. The Young's modulus is a ratio of a simple tensile stress applied to the object and a strain generated in parallel with the tension.

  The elastic image construction unit 34 is configured to include a frame memory and an image processing unit, and secures elastic image data output in time series from the elastic information calculation unit 32 in the frame memory. In contrast, image processing is performed.

  The color scan converter 36 has a function of adding hue information to the elastic image data from the elastic image construction unit 34. That is, the light is converted into the three primary colors of light, that is, red (R), green (G), and blue (B) based on the elastic image data. For example, elastic data having a large strain is converted into a red code, and simultaneously elastic data having a small strain is converted into a blue code.

  The switching addition unit 24 according to the present invention includes a frame memory, an image processing unit, and an image selection unit. Here, the frame memory stores tomographic image data from the monochrome scan converter 22 and elastic image data from the color scan converter 36. The image processing unit combines the tomographic image data and the elasticity image data secured in the frame memory by changing the combining ratio. The luminance information and hue information of each pixel of the composite image is obtained by adding the information of the black and white tomographic image and the color elastic image at the composite ratio. Further, the image selection unit selects an image to be displayed on the image display unit 26 from the tomographic image data and elasticity image data in the frame memory and the composite image data of the image processing unit.

  The operation unit 40 includes a keyboard having various keys, a trackball, and the like. By rotating the trackball of the operation unit 40, the region-of-interest setting unit 38 adjusts the position and range of the region of interest. Then, by pressing a confirmation key on the keyboard of the operation unit 40, the region-of-interest setting unit 38 confirms the adjusted region of interest. Then, the region-of-interest setting unit 38 transmits the set position information of the region of interest to the elasticity information calculation unit 32 and the image display unit 26.

  Here, the elastic information calculation unit 32 will be described with reference to FIGS. As shown in FIG. 2, the elasticity information calculation unit 32 calculates elasticity information including any one of strain and elastic modulus for the elasticity image based on the displacement output from the displacement measurement unit 30. Elastic information calculation unit 320, first region of interest elasticity information calculation unit 322 for calculating elasticity information of the first region of interest set by the region of interest setting unit 38, and second region of interest set by the region of interest setting unit 38 Using the plurality of elasticity information output from the second region of interest elasticity information calculation unit 324, the first region of interest elasticity information calculation unit 322, and the second region of interest elasticity information calculation unit 324 And an integrated calculation unit 326 that calculates a ratio of elasticity information between the region of interest and the second region of interest. The elastic image elasticity information calculation unit 320 calculates strain or elastic modulus of the living tissue from the displacement output from the displacement measurement unit 30 and the pressure value output from the pressure measurement unit 46, and based on the strain and elastic modulus Thus, elastic image data is generated.

  FIG. 3 shows one display form of the image display unit 26. FIG. 3A shows a display form in which a tomographic image, an elastic image, or a combined image of the tomographic image and the elastic image is displayed. FIG. 3 (b) shows a display form in which a graph showing the time transition of the distortion ratio is displayed. In this embodiment, the scanning direction is the X direction and the depth direction is the Y direction.

  As shown in FIG. 3 (a), the image display unit 26 displays a tomographic image, an elasticity image, or a composite image. The image area 60 of the reference deformable body 50 arranged in contact with the ultrasound probe 10 is displayed above (the area where the depth is shallow), and the image area 61 of the living tissue of the subject 10 is below (the area where the depth is deep). Is displayed. The image region 60 of the reference deformable body 50 in FIG. 3 (a) is hatched. The image region 61 of the biological tissue of the subject 10 includes a fat part, a mammary gland part, and a great pectoral muscle part. Here, it is assumed that there is a tumor in the mammary gland region, and the region of the mammary gland region where the distortion of the living tissue is small (hard) and is considered to be a tumor is the region of interest 62.

  Since the reference deformable body 50 is uniform, the image area 60 is displayed with a uniform echo level. Therefore, the boundary between the image area 60 and the image area 61 is clearly displayed. Therefore, the operator can discriminate between the image region 60 of the reference deformable body 50 and the image region 61 of the biological tissue of the subject 10.

  As shown in FIG. 3 (a), in a state where a tomographic image, an elasticity image, or a composite image is displayed on the image display unit 26, instruction information is input from the keyboard of the operation unit 40, and the displayed tomographic image is displayed. The elastic image or the composite image is frozen at an arbitrary timing. Then, the operator sets at least two regions of interest to be compared with the tomographic image, elasticity image, or synthesized image that are frozen and frozen by the operation unit 40 and the region of interest setting unit 38.

  At this time, the operator operates the operation unit 40 to set the regions of interest in the region of interest setting unit 38 in the image region 60 of the reference deformable body 50 and the image region 61 of the living tissue of the subject 10, respectively. Specifically, as shown in FIG. 3 (a), the first region of interest 63 (ROI1) is set to fit within the image region 60 of the reference deformable body 50, and the second region of interest 64 (ROI2) is a living body. The distortion of the living tissue in the tissue image region 61 is small (hard), and is set to a region of interest 62 that seems to be a lesion such as a tumor. Then, the region-of-interest setting unit 38 transmits the position information (X coordinate, Y coordinate) of the set two regions of interest to the image display unit 26.

  The region-of-interest setting unit 38 may automatically set the first region of interest 63 and the second region of interest 64 based on acoustic characteristics, position information, and the like.

  The region-of-interest setting unit 38 automatically uses the fact that the reference deformable body 50 is uniform or the attenuation rate of the reference deformable body 50 is lower than that of the living tissue of the subject 10, for example. 63 and the second region of interest 64 can also be set. Specifically, the acoustic characteristics of the biological tissue of the subject 10 and the acoustic characteristics of the reference deformable body 50 are stored in advance in a storage unit (not shown). Then, the region-of-interest setting unit 38 grasps the acoustic characteristics in each region of the obtained image, determines the acoustic characteristics of the reference deformable body 50 or the acoustic characteristics of the biological tissue of the subject 10, and A first region of interest 63 and a second region of interest 64 are set in the image region 60 and the image region 61 of the biological tissue of the subject 10, respectively. At this time, the region-of-interest setting unit 38 may set the second region of interest 64 in a region with the smallest distortion in the image region 61 of the living tissue.

  The region-of-interest setting unit 38 can also automatically set the region of interest according to the thickness of the reference deformable body 50, for example. Since the reference deformable body 50 has a thickness of about several millimeters, if the first region of interest 63 is set in an image region having a depth less than the thickness of the reference deformable body 50, that is, a shallow depth of several millimeters or less, the reference The first region of interest 63 is set in the image region 60 of the deformable body 50.

  In addition, when acquiring an elastic image, ultrasonic waves may be transmitted and received while the subject 10 is compressed by the ultrasonic probe 12. Since the central portion in the scanning direction (X direction) is pushed by the entire transducer surface of the ultrasound probe 12, the central portion in the scanning direction is more stably compressed than the left and right end portions in the scanning direction.

  That is, the region-of-interest setting unit 38 sets the region of interest at a depth equal to or less than the thickness of the reference deformable body 50 and at the center in the scanning direction. Then, the region-of-interest setting unit 38 transmits the position information of the first region of interest 63 and the second region of interest 64 to the image display unit 26, thereby, as shown in FIG. The first region of interest 63 can be set to 60.

  After setting the first region of interest 63 and the second region of interest 64, the region-of-interest setting unit 38 obtains the position information of the set first region of interest 63 and the second region of interest 64 as the first region-of-interest elasticity information calculation unit 322. And transmitted to the second region of interest elasticity information calculation unit 324. The position information of the first region of interest 63 and the second region of interest 64 is a two-dimensional coordinate on the display surface (cross section) of the image display unit 26. For example, if the first region of interest 63 and the second region of interest 64 are rectangular regions, the position information is at the four corners. If the first region of interest 63 and the second region of interest 64 is a circular region, the position information is the center of the circle. And radius length information.

  Then, the first region of interest elasticity information calculation unit 322 calculates the elasticity information in the first region of interest 63. For example, the first region-of-interest elasticity information calculation unit 322 calculates the strain average value by adding the distortion of each point in the first region of interest 63 and dividing the added value by the number of points of each point. Similarly, the second region of interest elasticity information calculation unit 324 calculates the elasticity information in the second region of interest 64.

  The image display unit 26 acquires elasticity information from the first region of interest elasticity information calculation unit 322 and the second region of interest elasticity information calculation unit 324, and displays the elasticity information in the first region of interest 63 and the second region of interest 64 Can do. Assuming that the elastic information is strain, for example, the image display unit 26 can display the average value of strain around the first region of interest 63 and the second region of interest 64, respectively. As shown in FIG. 3 (a), the average distortion value in the first region of interest 63 is displayed as ε1, and the average distortion value in the second region of interest 64 is displayed as ε2.

  The integrated calculation unit 326 calculates a strain ratio, an elastic modulus ratio, a stress distribution, and the like using a plurality of elasticity information output from the first region-of-interest elasticity information calculation unit 322 and the second region-of-interest elasticity information calculation unit 324.

  The integrated calculation unit 326 acquires the average strain value in the first region of interest 63 and the average strain value in the second region of interest 64 from the first region of interest elasticity information calculation unit 322 and the second region of interest elasticity information calculation unit 324. The distortion ratio between the first region of interest 63 and the second region of interest 64 is calculated. For example, the integrated calculation unit 326 calculates the distortion ratio using the average distortion value in the first region of interest 63 as a denominator and the average distortion value in the second region of interest 64 as a numerator. The integrated calculation unit 326 may calculate the distortion ratio using the average distortion value in the second region of interest 64 as a denominator and the average distortion value in the first region of interest 63 as a numerator.

  The image display unit 26 can acquire the distortion ratio from the integrated calculation unit 326 and display the distortion ratio in the first region of interest 63 and the second region of interest 64. For example, the image display unit 26 plots the distortion ratio for each acquisition time. As shown in FIG. 3 (b), it is possible to display a graph showing the time transition of the distortion ratio. In the present embodiment, the distortion ratio between the first region of interest 63 and the second region of interest 64 is calculated, but the integrated calculation unit 326 may calculate the ratio of other elasticity information. For example, the integrated calculation unit 326 may calculate the elastic modulus ratio based on the elastic modulus of the first region of interest 63 and the second region of interest 64.

  According to the present embodiment, elasticity information obtained from the strain or elastic modulus obtained in the region of interest set in the image region of the reference deformable body 50, and elasticity information obtained in the region of interest set in the image region of the attention site 62 The elastic information ratio can be calculated based on the above. Therefore, by comparing the distortion of the reference deformable body 50 and the attention site 62, the hardness of a lesioned part or the like can be quantitatively diagnosed.

(ROI1 tracking setting)
Here, Example 2 will be described with reference to FIGS. The difference from the first embodiment is that the region-of-interest setting unit 38 sets the first region of interest 63 corresponding to the position of the second region of interest 64. The first region of interest 63 (ROI1) is a region set in the image region 60 of the reference deformable body 50, and the second region of interest 64 (ROI2) is a region set in the living tissue of the subject 10.

  First, as described in the first embodiment, the region-of-interest setting unit 38, as shown in FIG. 4, has a small distortion (hard) in the tissue of the image region 61, and the region of interest 62 considered to be a lesion such as a tumor. A second region of interest 64 is set.

  Then, the region-of-interest setting unit 38 grasps position information (X coordinate) in the scanning direction of the second region of interest 64 set in the living tissue of the subject 10. Specifically, the position information in the scanning direction of the second region of interest 64 includes position information (X coordinate) corresponding to the left end of the second region of interest 64 indicated by a broken line 70 and a broken line 71, as shown in FIG. There is position information (X coordinate) corresponding to the right end of the second region of interest 64 indicated by, and position information (X coordinate) corresponding to the center of the second region of interest 64 indicated by the alternate long and short dash line 72. The region-of-interest setting unit 38 grasps the position information (X coordinate) of the left end, the right end, and the center of the second region of interest 64.

  Then, the region-of-interest setting unit 38, based on the position information (X coordinate) in the scanning direction of the second region of interest 64, the reference deformation body 50 is positioned so as to be located above (shallow depth) the second region of interest 64. The first region of interest 63 set in the image region 60 is automatically set. Specifically, the region-of-interest setting unit 38 calculates position information (X coordinate) corresponding to the left end of the second region of interest 64 and position information (X coordinate) corresponding to the right end of the second region of interest 64. Then, the region-of-interest setting unit 38 matches the left end and the right end of the second region of interest 64, and sets the first region of interest 63 to a depth that is less than the thickness of the reference deformable body 50 (several millimeters or less).

  The region-of-interest setting unit 38 reads position information (X coordinate) corresponding to the center of the second region of interest 64, matches the center of the second region of interest 64, and is equal to or less than the thickness of the reference deformable body 50 (several The first region of interest 63 may be set to a depth of less than or equal to millimeter. At this time, the width of the first region of interest 63 set in the image region 60 of the reference deformable body 50 by the region of interest setting unit 38 matches the width of the second region of interest 64 set in the living tissue of the subject 10. Thus, the first region of interest 63 can be set. The lateral width is a width in the scanning direction (X direction).

  The region-of-interest setting unit 38 follows the change in the changed position or range of the second region of interest 64 even if the position or range of the second region of interest 64 set in the living tissue of the subject 10 is changed. Thus, the first region of interest 63 set in the image region 60 of the reference deformable body 50 can be set automatically. Specifically, as shown in FIG. 5, the region-of-interest setting unit 38 changes the position or range of the region of interest in the second region of interest 64 by operating the operation unit 40. The region-of-interest setting unit 38 calculates position information (X coordinate) corresponding to the left end of the changed second region of interest 64 and position information (X coordinate) corresponding to the right end of the second region of interest 64. Then, the region-of-interest setting unit 38 matches the left end and the right end of the second region of interest 64, and sets the first region of interest 63 in the image region 60 of the reference deformable body 50. At this time, the region-of-interest setting unit 38 does not change the vertical width of the first region of interest 63 in the depth direction (Y direction).

  Thus, even if the second region of interest set in the living tissue of the subject 10 is changed, the width of the first region of interest 63 set in the image region 60 of the reference deformable body 50 by the region of interest setting unit 38 The first region of interest 63 can be set to match the width of the changed second region of interest 64.

  The region-of-interest setting unit 38 follows the position or range of the second region of interest 64 even if the shape of the second region of interest 64 is other than a rectangular shape, for example, a circle or an ellipse. Region 63 can be set. The reason why the second region of interest 64 is set to a shape other than the rectangular shape is that the living tissue of the subject 10 has various shapes, and the second region of interest 64 needs to be set according to the shape. On the other hand, since the shape of the image region 60 of the reference deformable body 50 is rectangular, the first region of interest 63 is set to be rectangular according to the shape of the image region 60.

  Specifically, as shown in FIG. 6, the region-of-interest setting unit 38 has position information (X coordinate) corresponding to the left end of the second region of interest 64 that is a shape other than a rectangle and the right end of the second region of interest 64. Corresponding position information (X coordinate) is calculated. Then, the region-of-interest setting unit 38 matches the left end and the right end of the second region of interest 64, and sets the first region of interest 63 in the image region 60 of the reference deformable body 50. At this time, the shape of the first region of interest 63 is set in accordance with the shape of the image region 60 of the reference deformable body 50.

  As described above, the first region of interest 63 set in the image region 60 of the reference deformable body 50 by the region of interest setting unit 38, regardless of the shape of the second region of interest set in the living tissue of the subject 10. The first region of interest 63 can be set so that the horizontal width of the second region of interest matches the horizontal width of the second region of interest 64.

  The region-of-interest setting unit 38 can set the first region of interest 63 according to the vertical width of the image region 60 of the reference deformable body 50. Note that the vertical width is the width in the depth direction (Y direction). Specifically, as shown in FIG. 7, the region-of-interest setting unit 38 corresponds to the upper end in the depth direction (Y direction) of the image region 60 of the reference deformation body 50 based on the acoustic characteristics of the reference deformation body 50. Position information (Y coordinate) corresponding to the position information (Y coordinate) and the lower end in the depth direction (Y direction) of the image region 60 of the reference deformable body 50 is calculated. Then, the region-of-interest setting unit 38 sets the first region of interest 63 so as to coincide with the upper and lower ends of the image region 60 of the reference deformable body 50 in the depth direction (Y direction).

  In this way, the region-of-interest setting unit 38 sets the first region of interest 63 set in the image region 60 of the reference deformable body 50 so that the vertical width of the first region of interest 63 matches the vertical width of the image region 60 of the reference deformable member 50. One region of interest 63 can be set.

  Then, as in the first embodiment, the integrated calculation unit 326 includes the elasticity information in the first region of interest 63 and the second region of interest 64 in the first region of interest elasticity information calculation unit 322 and the second region of interest elasticity information calculation unit 324. The elasticity information is acquired, and the ratio of the elasticity information of the first region of interest 63 and the second region of interest 64 is calculated.

  According to the present embodiment, if the second region of interest 64 is set, the first region of interest 63 is automatically set, so that the operation can be simplified. In addition, since the first region of interest 63 is set in association with the position of the second region of interest 64, the degree of compression can be made uniform, and the reproducibility and objectivity of the elastic information ratio can be improved. .

(Stress correction)
Here, Example 3 will be described with reference to FIGS. The difference from the first and second embodiments is that the integrated calculation unit 326 corrects the ratio of elasticity information according to the depth of the first region of interest 63 and the second region of interest 64.

  FIG. 8A shows a display form in which a tomographic image, an elastic image, or a composite image of the tomographic image and the elastic image is displayed. FIG. 8 (b) shows the relationship between the stress-depth characteristics.

  Since the stress applied to the living tissue of the subject 12 is attenuated as the depth increases, the ratio of the elastic information may not match the actual hardness value. For example, since the second region of interest 64 is set at a deeper depth than the first region of interest 63, the stress applied to the second region of interest 64 is smaller than the stress applied to the first region of interest 63. In this embodiment, the integrated calculation unit 326 corrects the ratio of the elastic information so that the influence of stress attenuation according to the depth of the first region of interest 63 and the second region of interest 64 is eliminated.

  Specifically, first, by using a simulation such as a finite element method (FEM), the stress-depth characteristics of the reference deformable body 50 and the biological tissue of the subject 12 (for example, a fat part, a mammary part, etc.) are obtained in advance. And stored in a storage unit (not shown). The image display unit 26 may display the stress-depth characteristics of the reference deformable body 50 or the living tissue of the subject 12 (for example, a fat part, a mammary gland part, etc.). The operator can confirm the consistency state of the ratio of the elastic information from the stress-depth characteristics of the reference deformable body 50 or the biological tissue of the subject 12 (for example, a fat part, a mammary gland part, etc.).

  As shown in FIG. 8 (b), the stress in the first region of interest 63 is σ1, and the average strain value is ε1. The stress in the second region of interest 64 is σ2, and the average strain value is ε2. The difference in stress between the first region of interest 63 and the second region of interest 64 is σ 1 −σ 2, and it can be seen that the stress applied in the second region of interest 64 is smaller than the stress applied in the first region of interest 63.

  The integrated calculation unit 326 acquires the elasticity information in the first region of interest 63 and the elasticity information in the second region of interest 64 from the first region of interest elasticity information calculation unit 322 and the second region of interest elasticity information calculation unit 324, and When calculating the ratio of the elastic information of the region of interest 63 and the second region of interest 64, the integrated calculation unit 326 calculates the ratio of the elastic information by multiplying the correction coefficient corresponding to the attenuation of stress.

  For example, as shown in the following formula, the integrated calculation unit 326 calculates by multiplying the distortion ratio by a correction coefficient corresponding to stress attenuation.

{Number 1}
Strain ratio * Correction factor = (ε1 / ε2) * (σ2 / σ1)
In this way, the integrated calculation unit 326 obtains a correction coefficient (σ2 / σ1) that is a rate of stress attenuation at the distance D between the first region of interest 63 and the second region of interest 64, and uses the correction coefficient as a distortion ratio. By multiplying, the ratio of the elastic information can be calculated so that the influence of stress attenuation according to the depth is eliminated.

  In the above description, the integrated arithmetic unit 326 uses a correction coefficient (ε1 / ε2) as a distortion ratio (ε1 / ε2) using the average value of distortion in the second region of interest 64 as a denominator and the average value of distortion in the first region of interest 63 as a numerator. Although the calculation is performed by multiplying by (σ2 / σ1), the integrated calculation unit 326 can also perform the calculation as shown in the following equation.

{Equation 2}
Strain ratio * Correction factor = (ε2 / ε1) * (σ1 / σ2)
In this way, the integrated arithmetic unit 326 uses the correction coefficient (σ1 It is also possible to calculate by multiplying / σ2).

  According to the present embodiment, the integrated calculation unit 326 can correct the ratio of the elastic information so that the influence of stress attenuation according to the depth of the first region of interest 63 and the second region of interest 64 is eliminated.

  1 Ultrasonic Diagnostic Equipment, 10 Subject, 12 Ultrasonic Probe, 14 Transmitter, 16 Receiver, 17 Transmission / Reception Controller, 18 Phased Adder, 20 Tomographic Image Component, 22 Monochrome Scan Converter, 24 Switching Addition Unit, 26 Image display unit, 28 RF signal frame data selection unit, 30 Displacement measurement unit, 32 Elastic information calculation unit, 34 Elastic image configuration unit, 36 Color scan converter, 38 Region of interest setting unit, 40 Operation unit, 50 Reference deformation body

Claims (11)

An ultrasonic probe; an elastic image forming unit that generates an elastic image at the tomographic region based on elasticity information of strain or elastic modulus at the tomographic region of the subject via the ultrasonic probe; and the elastic image In an ultrasonic diagnostic apparatus comprising a display unit for displaying
A region of interest in which a first region of interest is set in an image region of a reference deformable body installed on an ultrasound transmission / reception surface of the ultrasound probe, and a second region of interest is set in an image region of the biological tissue of the subject. An ultrasonic diagnostic apparatus comprising: a setting unit; and a calculation unit that calculates a ratio of the elasticity information based on elasticity information of the first region of interest and the second region of interest.   2. The region of interest setting unit sets the first region of interest and the second region of interest based on an acoustic characteristic of the reference deformable body and an acoustic characteristic of a biological tissue of the subject. Ultrasound diagnostic equipment.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the region-of-interest setting unit sets the second region of interest in a region having the smallest distortion in the image region of the biological tissue of the subject.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the region-of-interest setting unit sets the first region of interest at a depth equal to or less than a thickness of the reference deformable body and a central portion in a scanning direction.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the region-of-interest setting unit sets the first region of interest in accordance with a position of the second region of interest.   The region of interest setting unit sets the first region of interest to be positioned above the second region of interest based on position information of the second region of interest in the scanning direction. The ultrasonic diagnostic apparatus according to 1.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the region-of-interest setting unit sets the first region of interest so that a width of the first region of interest matches a width of the second region of interest. .   2. The region of interest setting unit according to claim 1, wherein the region of interest setting unit sets the first region of interest so that a vertical width of the first region of interest matches a vertical width of the image region of the reference deformable body. Ultrasonic diagnostic equipment.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the region-of-interest setting unit sets the first region of interest to a rectangular shape and sets the second region of interest to a shape other than a rectangular shape.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the calculation unit corrects the ratio of the elasticity information according to the depth of the first region of interest and the second region of interest.   2. The ultrasonic diagnostic apparatus according to claim 1, wherein the display unit displays a stress-depth characteristic of a living tissue of the reference deformable body or the subject.

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