JP2012213545A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of observing three-dimensional elastic images of high quality.SOLUTION: The ultrasonic diagnostic apparatus includes: an ultrasonic probe 2; an elastic volume data preparation part 20 for preparing elastic volume data by two-dimensional elastic images based on elastic information calculated by reflected echo signals received through the ultrasonic probe 2; a three-dimensional elastic image constitution part 21 for constituting three-dimensional elastic images on the basis of the elastic volume data; and an image display part 13 for displaying the three-dimensional elastic images. The ultrasonic diagnostic apparatus has a noise determination part 30 for determining the elastic volume data constituted of the plurality of two-dimensional elastic images including noise images as a noise volume, and the image display part does not display the three-dimensional elastic images by the elastic volume data determined as the noise volume.

Description

  The present invention relates to an ultrasonic diagnostic apparatus that displays a tomographic image of a diagnostic site in a subject using ultrasonic waves, and more particularly to an ultrasonic diagnostic apparatus that displays an elastic image based on elastic information such as strain or elastic modulus.

  The ultrasonic diagnostic apparatus uses ultrasonic waves to measure the ultrasonic reflectivity of a living tissue in a subject, and displays a tomographic image of a diagnostic region using the measured luminance as luminance. Furthermore, in recent years, in an ultrasound diagnostic apparatus, image correlation is taken and the amount of movement of the living tissue, for example, displacement is spatially differentiated to measure strain, or as a tissue-like diagnosis, a change in pressure is applied to the living tissue to obtain an elastic modulus. Measurement or display of an elasticity image based on elasticity information such as strain or elastic modulus is performed. The elastic image is displayed by giving hue information such as red, blue, or the like according to the strain or elastic modulus of the living tissue. By displaying the hard part of the living tissue mainly by the elastic image, the spread and size of the tumor can be easily diagnosed (for example, Patent Document 1).

  It is also possible to set the opacity of the 3D tomographic image so that the shape and volume of the hard or soft part of the 3D elastic image can be recognized when displaying the 3D elastic image overlaid on the 3D tomographic image. (For example, Patent Document 2).

JP 2000-60853 A JP 2008-259605 A

  In order to obtain a three-dimensional elasticity image, it is necessary to perform a three-dimensional scan and collect a plurality of two-dimensional elasticity images to form elasticity volume data. However, when a noise image is included in the collected two-dimensional elasticity image, a noise image (for example, a streak-like noise image) is displayed on the three-dimensional elasticity image configured by volume rendering.

  Displaying such a three-dimensional elastic image including a noise image gives unnecessary information to the operator and makes the observation of the three-dimensional elastic image complicated. In addition, when performing a long-time three-dimensional scan instead of real time, it is necessary to redo the three-dimensional scan, which wastes the operator's inspection time.

  An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of observing a high-quality three-dimensional elastic image.

  In order to achieve the object of the present invention, the elasticity of creating elastic volume data from an ultrasonic probe and a two-dimensional elastic image based on elastic information calculated from a reflected echo signal received via the ultrasonic probe An ultrasonic diagnostic apparatus comprising: a volume data creation unit; a 3D elasticity image configuration unit that configures a 3D elasticity image based on elasticity volume data; and an image display unit that displays a 3D elasticity image. A noise determination unit that determines elastic volume data composed of multiple 2D elastic images including images as noise volume, and the image display unit hides 3D elastic images based on elastic volume data determined as noise volume. To do.

  According to the present invention, a high-quality three-dimensional elastic image can be observed.

1 is a block diagram showing an ultrasonic diagnostic apparatus according to the present invention. The figure which shows the one display form of the image display part 13 which concerns on this invention The figure which shows the one display form of the image display part 13 which concerns on this invention The figure which shows the one display form of the image display part 13 which concerns on this invention The figure which shows Example 2 which concerns on this invention The figure which shows Example 2 which concerns on this invention The figure which shows Example 3 which concerns on this invention The figure which shows Example 3 which concerns on this invention The figure which shows Example 4 which concerns on this invention The figure which shows Example 4 which concerns on this invention

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, the ultrasound diagnostic apparatus has a probe 2 used in contact with the subject 1, and repeatedly transmits ultrasonic waves to the subject 1 through the probe 2 at time intervals. Transmitting unit 3, receiving unit 4 receiving a time-series reflected echo signal generated from the subject 1, and phasing addition unit generating the RF signal data in time series by phasing and adding the received reflected echo 6 is provided.

  In addition, the ultrasonic diagnostic apparatus includes a tomographic image configuration unit 7 that configures a two-dimensional tomographic image based on the RF signal frame data generated by the phasing addition unit 6, and a two-dimensional configuration configured by the tomographic image configuration unit 7. 2D tomographic image storage unit 8 that stores tomographic images together with acquisition positions, 2D tomographic images stored in 2D tomographic image storage unit 8 and 3D coordinate conversion based on acquisition positions of 2D tomographic images A tomographic volume data generating unit 9 that generates tomographic volume data, a 3D tomographic image constructing unit 10 that performs volume rendering based on the luminance and opacity of the tomographic volume data, and forms a three-dimensional tomographic image; and tomographic volume data A tomographic multi-frame constructing unit 11 is provided that creates a black and white tomographic image of an arbitrary cross section from the tomographic volume data created by the creating unit 9.

  In addition, the ultrasonic diagnostic apparatus includes an RF signal frame data storage unit 14 that stores the RF signal frame data output from the phasing addition unit 6, and an RF signal frame data selection that selects at least two pieces of RF signal frame data. 15, a displacement measuring unit 16 that measures the displacement of the living tissue of the subject 1 using the selected RF signal frame data, and an elasticity information calculating unit 17 that obtains elastic information from the displacement measured by the displacement measuring unit 16 An elastic image composing unit 18 that composes a two-dimensional elastic image from the elastic information computed by the elastic information computing unit 17, a two-dimensional elastic image that stores the two-dimensional elastic image composed of the elastic image composing unit 18 and its acquisition position An image storage unit 19, an elastic volume data creation unit 20 that performs three-dimensional coordinate conversion based on the two-dimensional elasticity image stored in the two-dimensional elasticity image storage unit 19 and its acquisition position, and generates elastic volume data; Boli Volume rendering based on the elasticity information and opacity of the volume data, and 3D elasticity image composition unit 21 that composes a 3D elasticity image, and 2D of an arbitrary cross section from the elasticity volume data created by the elasticity volume data creation unit 20 Elastic multi-frame construction unit 22 for creating an elastic image, switching composition unit 12 for synthesizing a two-dimensional tomographic image and a two-dimensional elastic image, and synthesizing a three-dimensional tomographic image and a three-dimensional elastic image, and switching An image display unit 13 that displays a synthesized image, a two-dimensional tomographic image, and the like synthesized by the synthesis unit 12 is provided.

  Furthermore, the ultrasonic diagnostic apparatus includes a noise determination unit 30 that determines, as a noise volume, elastic volume data composed of a plurality of two-dimensional elastic images including a noise image.

  In the ultrasonic diagnostic apparatus, a control unit 25 including a CPU that controls each component and an operation unit 24 that gives instructions to the control unit 25 are installed. The operator can designate the hue of the elastic image, the region of interest (ROI) for displaying the elastic image, the tomographic image, the frame rate of the elastic image, or the like using the operation unit 24.

  The probe 2 is formed by arranging a plurality of transducers, and has a function of electronically performing beam scanning and transmitting / receiving ultrasonic waves to / from the subject 1 via the transducers. The probe 2 includes a probe head composed of a plurality of transducers having a rectangular shape or a sector shape. The probe head is mechanically shaken in a direction orthogonal to the arrangement direction of the plurality of transducers to generate ultrasonic waves 3 Can send and receive in the dimension. Note that the ultrasonic probe 2 may be one in which a plurality of transducers are two-dimensionally arranged so that transmission / reception of ultrasonic waves can be electronically controlled.

  The transmission unit 3 has a function of driving the probe 2 to generate a transmission pulse for generating an ultrasonic wave and setting a convergence point of the transmitted ultrasonic wave to a certain depth. The receiving unit 4 amplifies the reflected echo signal received by the probe 2 with a predetermined gain to generate an RF signal, that is, a received signal. The phasing / adding unit 6 inputs the RF signal amplified by the receiving unit 4 and performs phase control, forms an ultrasonic beam converged at a plurality of convergence points, and generates RF signal frame data.

  The tomographic image constructing unit 7 constructs a gray scale tomographic image of the subject, for example, a black and white two-dimensional tomographic image, based on the RF signal frame data from the phasing adder 6. The tomographic image construction unit 7 inputs the RF signal frame data output from the phasing addition unit 6 based on the setting conditions in the control unit 25 and receives signals such as gain correction, log compression, detection, contour enhancement, and filter processing Processing is performed to form a two-dimensional tomographic image.

  The RF signal frame data selection unit 15 selects one set, that is, two RF signal frame data from a plurality of RF signal data from the phasing addition unit 6 stored in the RF signal frame data storage unit 14. For example, the RF signal frame data storage unit 14 sequentially secures RF signal data generated based on the time series, that is, the frame rate of the image from the phasing addition unit 6 in the frame memory, and responds to a command from the control unit 25. At the same time, the RF signal frame data (N-1), which is secured in the past in time, is selected by the RF signal frame data selection unit 15 as the first data. 2, N-3... NM) to select one RF signal frame data (X). Here, N, M, and X are index numbers assigned to the RF signal frame data, and are natural numbers.

  The displacement measuring unit 16 obtains a displacement of a living tissue from a set of RF signal frame data. For example, the displacement measurement unit 16 performs one-dimensional or two-dimensional correlation processing from one set of data selected by the RF signal frame data selection unit 15, that is, RF signal frame data (N) and RF signal frame data (X). Then, a one-dimensional or two-dimensional displacement distribution related to the displacement and movement vector corresponding to each point of the tomographic image, 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 17 calculates the elasticity of the living tissue corresponding to each point on the tomographic image from the measurement value output from the displacement measurement unit 16, for example, the displacement and the pressure value output from the pressure measurement unit (not shown). Information is calculated. The elastic information is any one of strain, elastic modulus, displacement, viscosity, strain ratio, and the like. For example, the strain is calculated by spatially differentiating the movement amount of the living tissue, for example, the displacement.

  The elastic image construction unit 18 is configured to include a frame memory and an image processing unit, and secures the elastic frame data output in time series from the elastic information calculation unit 17 in the frame memory, and stores the secured frame data. The image processing unit performs image processing.

  The elastic image is converted into three primary colors of light, that is, red (R), green (G), and blue (B) based on the elastic frame data, and is displayed on the image display unit 13 as a color image. 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. Note that the gradation of red (R), green (G), and blue (B) has 256 levels, 255 means display at the maximum luminance, and conversely 0 means no display at all.

  The probe 2 can measure the transmission / reception direction (θ, φ) simultaneously with the transmission / reception of ultrasonic waves, and the tomographic volume data creation unit 9 transmits / receives the transmission / reception direction (θ, φ) corresponding to the acquisition position of the two-dimensional tomographic image. ), Three-dimensional conversion is performed on a plurality of two-dimensional tomographic images to generate tomographic volume data.

  The three-dimensional tomographic image construction unit 10 performs volume rendering using the following equations (1) to (3) that compose a three-dimensional tomographic image from the tomographic volume data.

Cout (i) = Cout (i-1) + (1−Aout (i-1)) ・ A (i) ・ C (i) ・ S (i) ・ ・ ・ (1)
Aout (i) = Aout (i-1) + (1−Aout (i-1)) ・ A (i) (2)
A (i) = BOpacity [C (i)] (3)
C (i) is the luminance value of the i-th voxel existing on the line of sight when a 3D tomographic image is viewed from a certain point on the created 2D projection plane. Cout (i) is an output pixel value. For example, when N voxel luminance values are arranged on the line of sight, a luminance value Cout (N−1) obtained by integrating i = 0 to N−1 is a pixel value to be finally output. Cout (i-1) indicates the integrated value up to the i-1th.

  A (i) is the opacity of the i-th luminance value existing on the line of sight, and is a tomographic opacity table (fault opacity table) that takes values from 0 to 1.0 as shown in (3) above. The tomographic opacity table determines the contribution rate on the output two-dimensional projection plane (three-dimensional tomographic image) by referring to the opacity from the luminance value.

  S (i) is a weight component for shading calculated from the luminance C (i) and the gradient obtained from the surrounding pixel values. For example, the normal of the surface centered on the light source and voxel i matches. In this case, 1.0 is given for the strongest reflection, and 0.0 is given when the light source and the normal line are orthogonal to each other.

Cout (i) _and Aout (i) both have an initial value of 0. As shown in (2) above, Aout (i) is integrated and converges to 1.0 each time it passes through the voxel. Therefore, as shown in (1) above, when the integrated value Aout (i-1) of the opacity up to the (i-1) th is about 1.0, the luminance value C (i) after the ith is included in the output image. Not reflected.

  The tomographic multi-frame construction unit 11 constructs an arbitrary cross-sectional tomographic image at an arbitrary cross-sectional position from the tomographic volume data. The arbitrary cross-sectional position can be arbitrarily set by the operator using the operation unit 24, and the set arbitrary cross-sectional position is output to the tomographic multi-frame configuration unit 11 through the control unit 25. The operator can set a plurality of arbitrary cross-sectional positions, and the tomographic multi-frame configuration unit 11 can configure a plurality of arbitrary cross-sectional tomographic images for a plurality of arbitrary cross-sectional positions.

In a probe capable of three-dimensional scanning, the RF signal frame data is obtained spatially continuously in a direction orthogonal to the arrangement direction of the plurality of transducers, and accordingly, an elastic image is obtained accordingly. A two-dimensional elasticity image storage unit 19 stores the two-dimensional elasticity image obtained spatially continuously by the elasticity image construction unit 18 and its acquisition position. Based on the two-dimensional elasticity image stored in the two-dimensional elasticity image storage unit 19 and the transmission / reception direction (θ, φ) corresponding to the acquisition position, the elasticity volume data creation unit 20 Conversion is performed to generate elastic volume data.
The three-dimensional elastic image construction unit 21 performs volume rendering on the converted elastic volume data using the following equations (4) to (6) to create a three-dimensional elastic image.

Eout (i) = Eout (i-1) + (1−Aout (i-1)) ・ A (i) ・ E (i) ・ S (i) (4)
Aout (i) = Aout (i-1) + (1−Aout (i-1)) ・ A (i) (5)
A (i) = EOpacity [E (i)] (6)
E (i) is i-th elasticity information existing on the line of sight when a 3D elasticity image is viewed from a certain point on the created 2D projection plane. Eout (i) is an output pixel value. For example, when the elasticity information of N voxels is arranged on the line of sight, an integrated value Eout (N−1) obtained by integrating the elasticity information from i = 0 to N−1 is a pixel value that is finally output. Eout (i-1) indicates the integrated value up to the (i-1) th. A (i) is the opacity of elasticity information existing i-th on the line of sight, and is an elasticity opacity table shown in Expression (6).

  S (i) is a weight component for shading calculated from the elasticity information E (i) and the gradient obtained from the surrounding elasticity information.For example, the normal of the surface centered on the light source and voxel i is the same. In this case, 1.0 is given for the strongest reflection, and 0.0 is given when the light source and the normal line are orthogonal to each other.

Eout (i) _and Aout (i) both have an initial value of 0, and Aout (i) is integrated and converges to 1.0 each time it passes through a voxel as shown in equation (5). Therefore, as shown in equation (4), when the integrated value Aout (i-1) of the opacity of the voxels up to i-1 is about 1.0, the i-th and subsequent voxel values E (i) are output. Not reflected in the image.

  The elastic multi-frame forming unit 22 forms an arbitrary elastic tomographic image at an arbitrary cross-sectional position from the elastic volume data. The arbitrary cross-sectional position can be arbitrarily set by the operator using the operation unit 24, and the set arbitrary cross-sectional position is output to the elastic multi-frame configuration unit 22 through the control unit 25. The operator can set a plurality of arbitrary cross-sectional positions, and the elastic multi-frame configuration unit 22 can configure a plurality of arbitrary elastic tomographic images for the plurality of arbitrary cross-sectional positions.

  The switching combining unit 12 combines the three-dimensional elasticity image and the three-dimensional tomographic image. The switching composition unit 12 includes a frame memory, an image processing unit, and an image selection unit. Here, the frame memory includes a 3D tomographic image from the 3D tomographic image construction unit 10, an arbitrary cross-sectional tomographic image from the tomographic multiframe construction unit 11, and a 3D elastic image from the 3D elastic image construction unit 21. An arbitrary cross-sectional elasticity image from the elastic multi-frame component 22 is stored. In addition, the image processing unit adds the three-dimensional tomographic image and the three-dimensional elastic image secured in the frame memory, or the arbitrary cross-sectional tomographic image and the arbitrary cross-sectional elastic image at a set ratio according to a command from the control unit 25. Are synthesized. The luminance information and hue information of each pixel of the composite image is obtained by adding each information of the black and white tomographic image and the color elastic image at a set ratio. Further, the image selection unit selects the image display unit 13 from the three-dimensional tomographic image and the three-dimensional elastic image in the frame memory, or the arbitrary cross-sectional tomographic image and the arbitrary cross-sectional elastic image and the composite image data of the image processing unit. The image to be displayed is selected according to a command from the control unit 25. Note that these tomographic images and elastic images may be displayed separately without being synthesized.

  Next, the noise determination unit 30 that is a feature of the present invention will be described. FIG. 2 shows one display form of the image display unit 13. Here, the display state of the image display unit 13 that displays the two-dimensional elastic image 50 and the three-dimensional elastic image 60 in parallel is shown. Note that the present embodiment is effective not only in this display form but also in a display form that simultaneously displays a plurality of two-dimensional elastic images and three-dimensional elastic images of three orthogonal cross sections. A plurality of two-dimensional elastic images are formed by the elastic multi-frame configuration unit 22.

  In FIG. 2, a soft region 52 and a hard region 54 are shown in the two-dimensional elastic image 50, and a soft three-dimensional region 62 and a hard three-dimensional region 64 are shown in the three-dimensional elastic image 60. Although not shown, a 2D composite image obtained by combining the 2D elastic image 50 and the 2D tomographic image is displayed, or a 3D composite image obtained by combining the 3D elastic image 60 and the 3D tomographic image is displayed. May be. When displaying a two-dimensional composite image, the tomographic multi-frame construction unit 11 forms a two-dimensional tomographic image having the same cross section as the two-dimensional elasticity image.

  FIG. 2 shows a state where there is no noise image in the two-dimensional elastic image constituting the elastic volume data. Therefore, a spherical hard three-dimensional elastic image 60 of the hard three-dimensional region 64 is displayed. A cross section 66 displayed in the three-dimensional elastic image 60 indicates the position of the cross section of the two-dimensional elastic image 50 displayed in parallel.

  Since the two-dimensional elasticity image is acquired while repeating the compression, the three-dimensional elasticity image obtained by the two-dimensional elasticity image acquired when the compression is not appropriate may include a noise image. As shown in FIG. 3, when the elastic volume data composed of a two-dimensional elastic image including a noise image is rendered, a three-dimensional elastic image 60 is displayed. A cross section 66 indicating the position of the cross section of the two-dimensional elasticity image 50 includes a noise image 72. The cross section 68 includes a noise image 74. The cross section 70 includes a noise image 78.

  In this way, even if there are several 2D elastic images including noise images, if there are 2D elastic images including noise in front of the line of sight, the desired hard 3D region 64 existing in the back is observed. There are cases where it is not possible. In addition, when updating a 3D elasticity image in real time, a 3D elasticity image including a 3D elasticity image without a noise image acquired when compression is appropriate and a noise image acquired when compression is not appropriate Are displayed alternately.

  Therefore, in this embodiment, the noise determination unit 30 determines whether or not a noise image is included in each two-dimensional elastic image constituting the elastic volume data of the three-dimensional elastic image. Then, the noise determination unit 30 determines the elastic volume data constituted by a plurality of two-dimensional elastic images including a noise image as a noise volume.

  The noise determination unit 30 is a two-dimensional image based on an autocorrelation value between a pair of RF signal frame data that is a basis of a two-dimensional elasticity image or an evaluation value obtained from a region determined to have display value in the two-dimensional elasticity image. It is determined whether or not a noise image is included in the elastic image. For example, when the autocorrelation value between a pair of RF signal frame data that is the basis of the two-dimensional elasticity image is higher than a predetermined value, the degree of coincidence between the pair of RF signal frame data is high, and a noise image is included. It is unlikely that

  Therefore, when the autocorrelation value of the pair of RF signal frame data is higher than the predetermined value, the noise determination unit 30 recognizes that the measurement is performed in a stable measurement state, and determines that the noise image is not included in the two-dimensional elastic image. To do. When the autocorrelation value of the pair of RF signal frame data is lower than a predetermined value, the noise determination unit 30 recognizes that the measurement is performed in an unstable measurement state, and determines that the noise image is included in the two-dimensional elastic image.

  Further, the noise determination unit 30 determines whether or not the elasticity information about each measurement point of the two-dimensional elasticity image is normally measured, and determines whether or not the noise image is included in the two-dimensional elasticity image Can also be performed. The noise determination unit 30 compares, for example, the elasticity information at each measurement point with the average value or standard deviation value of the elasticity information of the two-dimensional elasticity image, and determines whether the elasticity information at each measurement point has been normally measured. Based on this, it is determined whether there is display value. The noise determination unit 30 determines that the noise image is not included in the two-dimensional elastic image when the region determined to have display value is smaller than the predetermined region. The noise determination unit 30 determines that the noise image is included in the two-dimensional elastic image when the region determined to have no display value is larger than the predetermined region.

  In this way, the noise determination unit 30 determines the presence or absence of noise images in all the two-dimensional elastic images constituting the elastic volume data, and the number of low-quality two-dimensional elastic images, that is, the number of two-dimensional elastic images including noise images. And the number of two-dimensional elastic images including a noise image is stored.

そして、割合αが任意のしきい値より大きいとき、ノイズ判定部30は、その弾性ボリュームデータをノイズボリュームとして判定し、判定結果を弾性ボリュームデータ作成部20又は3次元弾性画像構成部21に出力する。また、割合αと比較する任意のしきい値は固定値でもよいし、操作者が操作部24を通じて設定可能であってもよい。 Then, the noise determination unit 30 obtains a ratio α of the number of two-dimensional elastic images including the noise image to the number of two-dimensional elastic images constituting the elastic volume data of the three-dimensional elastic image using the following equation (7).

When the ratio α is larger than an arbitrary threshold value, the noise determination unit 30 determines the elastic volume data as a noise volume, and outputs the determination result to the elastic volume data creation unit 20 or the three-dimensional elastic image configuration unit 21. To do. The arbitrary threshold value to be compared with the ratio α may be a fixed value or may be set by the operator through the operation unit 24.

  For example, if the number of two-dimensional elastic images constituting the elastic volume data is 100, and the number of two-dimensional elastic images including noise images is 10 or more, the noise determination unit 30 converts the elastic volume data to the noise volume. Judge as. If you want to display a 3D elastic image that contains no noise image, or if the number of 2D elastic images that include the noise image is one or more, the noise determination unit 30 determines that the elastic volume data is a noise volume. To do. The operator can adjust the accuracy of the elastic volume data by appropriately changing an arbitrary threshold value to be compared with the ratio α.

  When the elastic volume data is determined to be a noise volume by the noise determination unit 30, the elastic volume data creation unit 20 does not output the elastic volume data, and the image display unit 13 displays a three-dimensional elastic image as shown in FIG. 60 is not displayed, that is, the three-dimensional elastic image 60 is not displayed. Further, when the elastic volume data is determined to be a noise volume by the noise determination unit 30, the 3D elastic image construction unit 21 may not output a 3D elastic image.

  As shown in FIG. 4, when the three-dimensional elastic image including the noise image is not displayed, the image display unit 13 can also display a warning mark 80. The warning mark 80 informs the operator that the three-dimensional elasticity image is not displayed due to the noise image, and the compression method can be corrected. In the present embodiment, the warning mark 80 is shown. However, the warning mark 80 is not limited to this, and an audio warning may be used. The image display unit 13 is equipped with a speaker so that an audio warning can be given.

  As described above, according to the present embodiment, the noise determination unit 30 that determines elastic volume data configured by a plurality of two-dimensional elastic images including a noise image as a noise volume is provided, and the image display unit 13 is determined to be a noise volume. The 3D elasticity image based on the elasticity volume data was hidden.

  Therefore, a three-dimensional elastic image with a lot of noise images is not displayed, only a three-dimensional elastic image without or with little noise is displayed, and the operator can observe a high-quality three-dimensional elastic image.

  Next, Example 2 will be described with reference to FIGS. The difference from the first embodiment is that the storage unit 23 stores elastic volume data or a three-dimensional elastic image. When the elastic volume data is determined to be a noise volume by the noise determination unit 30, the storage unit 23 stores the elastic volume data. Alternatively, a three-dimensional elastic image based on the elastic volume data is not read out.

  As shown in FIG. 5, the storage unit 23 included in the ultrasonic diagnostic apparatus includes a two-dimensional tomographic image from the tomographic image construction unit 7, a tomographic volume data from the tomographic volume data creation unit 9, and a three-dimensional tomographic image. Three-dimensional tomographic image from the image construction unit 10, arbitrary cross-sectional tomographic image from the tomographic multi-frame construction unit 11, two-dimensional elasticity image from the elastic image construction unit 18, and elastic volume data from the elastic volume data creation unit 20 And a three-dimensional elasticity image from the three-dimensional elasticity image construction unit 21 and an arbitrary cross-sectional elasticity image from the elasticity multi-frame construction unit 22 are stored. Further, the storage unit 23 reads out the stored image in response to the command from the control unit 25 and reproduces the image on the image display unit 13. FIG. 6A shows that the display screen 90, the display screen 92, the display screen 94, and the display screen 98 are sequentially displayed on the image display unit 13 along the time axis. The display screen is a display form in which the two-dimensional elastic image 50 and the three-dimensional elastic image 60 are displayed in parallel on the image display unit 13, as shown in FIG.

  It is assumed that the display screen 90, the display screen 92, and the display screen 98 display a three-dimensional elastic image determined not to be a noise volume, and the display screen 94 displays a three-dimensional elastic image determined to be a noise volume. The storage unit 23 stores elastic volume data or three-dimensional elastic images belonging to the display screen 90 to the display screen 98 in time series.

  When the elastic volume data or the three-dimensional elastic image is stored in the storage unit 23, the noise determination unit 30 adds and stores a noise flag. The noise flag is represented by, for example, 0 and 1. When the elastic volume data is determined to be a noise volume by the noise determination unit 30, noise flag = 1 is added. When the noise determination unit 30 determines that the elastic volume data is not a noise volume, a noise flag = 0 is added.

  When the elastic volume data or 3D elastic image stored from the storage unit 23 is reproduced by the operator, only the 3D elastic image based on the elastic volume data with the noise flag = 0 is reproduced. Therefore, as shown in FIG. 6B, the display screen 90, the display screen 92, and the display screen 98 are reproduced in order and displayed on the image display unit 13. The display screen 94 including the three-dimensional elasticity image determined as the noise volume is not reproduced.

  When reproducing only a three-dimensional elastic image based on elastic volume data with a noise flag = 0, a three-dimensional elastic image based on elastic volume data with the latest noise flag = 0 may be displayed, or several noise flags = A three-dimensional elasticity image based on 0 elasticity volume data may be displayed on the image display unit 13 so that the operator can select it.

  When the operator tries to reproduce the elastic volume data or the three-dimensional elastic image stored from the storage unit 23 when the display screen 94 of FIG. 6 is acquired, according to this embodiment, the latest elastic volume data is noise. A display screen 92 displaying a three-dimensional elastic image determined not to be a volume is reproduced.

  As described above, according to the present embodiment, the operator can observe a high-quality three-dimensional elastic image.

  Next, Example 3 will be described with reference to FIGS. The difference from the first and second embodiments is that, when the elastic volume data is determined not to be a noise volume by the noise determination unit 30, the elastic volume data creation unit 20 includes a noise image adjacent to a two-dimensional elastic image including a noise image. There is no point to create interpolated elastic volume data by interpolating with no two-dimensional elastic image.

  In the noise determination unit 30, the ratio α is obtained using Expression (7) as in the first embodiment. When the ratio α is smaller than an arbitrary threshold value, the elastic volume data is determined as normal volume data that does not contain noise or has little noise, and the determination result is output to the elastic volume data creation unit 20.

  However, when 0 <α <any threshold value, elastic volume data including at least a noise image is created, and a three-dimensional elastic image 503 including a small amount of noise image is displayed.

  Therefore, as shown in FIGS. 7 and 8, it is assumed that an interpolation ON / OFF button 100 that can be operated by the operation unit 24 is presented to the operator. When the operator presses the interpolation ON button, a signal is sent to the elastic volume data creation unit 20 through the control unit 25. The elastic volume data creation unit 20 receives the interpolation ON button signal, and the noise determination unit 30 determines that the elastic volume data is not a noise volume, that is, a normal volume, a two-dimensional elastic image including a noise image is obtained. Interpolation is performed with an elastic image not including an adjacent noise image, and interpolation elastic volume data is output. Then, the 3D elasticity image construction unit 21 performs rendering on the interpolation elasticity volume data, and the image display unit 13 displays the interpolation 3D elasticity image as shown in FIG.

  According to the determination result of the noise determination unit 30, the interpolation is valid only when the elastic volume data is not a noise volume, that is, normal elastic volume data. This is because, in the elastic volume data determined as normal elastic volume data, there are few two-dimensional elastic images including noise images, and natural interpolation elastic volume data can be created with a minimum of interpolation processing. Conversely, the elastic volume data determined as a noise volume has many two-dimensional elastic images including noise, and even if interpolation is performed, it can become unnatural interpolation elastic volume data.

  Therefore, the interpolation ON / OFF button 100 may be effective only when the noise determination unit 30 determines that the elastic volume data is normal. Further, when the operator presses the interpolation OFF button, as shown in FIG. 7, a three-dimensional elasticity image based on the elasticity volume data before the interpolation may be displayed and switched.

  As an interpolation method, for example, it is assumed that the elastic volume data is composed of N two-dimensional elastic images, and the value of the two-dimensional elastic information at the coordinates (x, y) of the a-th two-dimensional elastic image is E (x , y, a).

  When the two-dimensional elastic images of the a-th, b-th and c-th (0 <a <b <c <N) are adjacent in order, and the b-th two-dimensional elastic image includes a noise image The elastic volume data creation unit 20 performs interpolation by using the following equation (8) for all (x, y) coordinates of the two-dimensional elastic image.

E (x, y, b) = (E (x, y, a) + E (x, y, c)) / 2 (8)
If Expression (8) is used, a two-dimensional elastic image including a noise image is interpolated with an average image of two-dimensional elastic images not including an adjacent noise image.

  Also, for example, the two-dimensional elastic images of the a-th, b-th, c-th, d-th, and e-th (0 <a <b <c <N) are sequentially adjacent to each other, and the c-th two-dimensional When the elastic image includes a noise image, the elastic volume data creation unit 20 may perform interpolation by using the following equation (9) for all (x, y) coordinates of the two-dimensional elastic image. Good.

E (x, y, c)
= 0.15 × E (x, y, a) + 0.35 × E (x, y, b) + 0.35 × E (x, y, d) + 0.15 × E (x, y, e) ... (9)
If Expression (9) is used, a two-dimensional elastic image including a noise image is interpolated with a two-dimensional elastic image obtained by multiplying a two-dimensional elastic image not including a plurality of neighboring noise images by a weighting coefficient and adding the weighting coefficient. Of course, the weighting factor is not limited to the value of equation (9).

  Other interpolation methods may be used, and the elastic volume data creation unit 20 may perform interpolation by replacing a two-dimensional elastic image including a noise image with a two-dimensional elastic image not including an adjacent noise image.

  As described above, according to the present embodiment, the operator can observe a high-quality three-dimensional elastic image constituted by a two-dimensional elastic image not including a noise image.

  Next, Example 4 will be described with reference to FIG. The difference from the first to third embodiments is that the probe head composed of a plurality of transducers of the probe 2 starts a three-dimensional scan based on the cumulative number of two-dimensional elastic images including noise images in the elastic volume data. It is a point to move to a position.

  FIG. 9 (a) shows a three-dimensional scan in which the probe 2 is mechanically scanned. The probe 2 rotates the probe head from the probe head position 110 to the probe head position 118 with a motor. Meanwhile, the probe head repeats scanning and collects the acquired two-dimensional elastic images, thereby creating one elastic volume data.

  Moving the probe head from the probe head position 110 to the probe head position 118 is a one-way three-dimensional scan, and in addition, the probe head is moved from the probe head position 118 to the probe head position 110. This movement is called a one-way three-dimensional scan. Normally, one elastic volume data is created by one-way three-dimensional scan. At this time, the probe head position 110 is the start position of the three-dimensional scan, and the probe head position 118 is the end position of the three-dimensional scan.

  When the noise determination unit 30 determines that the two-dimensional elastic image sequentially acquired during the one-way three-dimensional scan is a two-dimensional elastic image including the noise image, the noise determination unit 30 calculates the cumulative number β of the two-dimensional elastic images including the noise image. Hold. For example, when the cumulative number β of two-dimensional elastic images including a noise image becomes larger than an arbitrary threshold at the time of the probe head position 114, the noise determination unit 30 sends a signal to the probe 2. As shown in FIG. 9B, the probe 2 returns the probe head from the probe head position 114 to the probe head position 110 that is the start position of the three-dimensional scan. Then, one-way three-dimensional scanning is performed again. The probe 2 can also move the probe head from the probe head position 114 to the probe head position 118 that is the start position of the three-dimensional scan in the return path. A three-dimensional scan of one return path can also be performed.

  Furthermore, the moving distance from the current probe head position to the probe head position 110, which is the 3D scan start position, is compared with the moving distance from the current probe head position to the probe head position 118. The probe 2 can be moved to a shorter moving distance (the probe head position 110 or the probe head position 118) to perform a three-dimensional scan.

  The arbitrary threshold value may be a fixed value or may be set by the operator through the operation unit 24.

  The present embodiment can also be applied to a case where one elastic volume data is generated by one reciprocating three-dimensional scan, or a case where one elastic volume data is generated by three or more three-dimensional scans.

  In addition, even when the probe 2 is moved manually to create one elastic volume data, this embodiment is applied, and the cumulative number β of two-dimensional elastic images including noise images becomes larger than an arbitrary threshold value. The scan can be stopped at the time.

  Furthermore, one display form of the image display unit 13 during the three-dimensional scan in the fourth embodiment is shown in FIG. As shown in FIG. 10, the noise determination unit 30 outputs the cumulative number β to the image display unit 13, and the image display unit 13 displays the noise frame number 120 that is the cumulative number β. At this time, the image display unit 13 can also display the number of noise frames 120 with respect to the total number of acquired two-dimensional elastic images. The operator can recognize the proportion of the two-dimensional elastic image including the noise image. Therefore, the situation of the two-dimensional elastic image including the noise image is transmitted to the operator, which leads to feedback to the compression technique.

  According to the present embodiment, for example, when the probe is mechanically scanned for a long time to obtain elastic volume data, or when the probe is manually scanned to obtain elastic volume data, one forward path or one reciprocation is performed. Without waiting for the end of the 3D scan, it can be determined whether the elastic volume data has a lot of noise images, and the 3D scan can be efficiently redone.

  1 subject, 2 probe, 3 transmitter, 4 receiver, 5 ultrasound transmission / reception controller, 6 phasing adder, 7 tomographic image construction unit, 8 2D tomographic image storage unit, 9 tomographic volume data creation unit , 10 3D tomographic image construction unit, 11 tomographic multi-frame construction unit, 12 switching composition unit, 13 image display unit, 14 RF signal frame data storage unit, 15 RF signal frame data selection unit, 16 displacement measurement unit, 17 elasticity information Calculation unit, 18 Elastic image configuration unit, 19 2D elastic image storage unit, 20 Elastic volume data creation unit, 21 3D elastic image configuration unit, 22 Elastic multi-frame configuration unit, 23 Storage unit, 24 operation unit, 25 control unit , 30 Noise detector

Claims (8)

An ultrasonic probe, an elastic volume data generating unit that generates elastic volume data from a two-dimensional elastic image based on elastic information calculated by a reflected echo signal received via the ultrasonic probe, and the elasticity An ultrasonic diagnostic apparatus comprising a three-dimensional elasticity image constructing unit that constructs a three-dimensional elasticity image based on volume data, and an image display unit that displays the three-dimensional elasticity image,
A noise determination unit configured to determine, as a noise volume, the elastic volume data including a plurality of two-dimensional elastic images including a noise image, and the image display unit includes the three-dimensional elasticity based on the elastic volume data determined to be a noise volume. An ultrasonic diagnostic apparatus characterized by hiding an image.   The ultrasonic diagnostic apparatus according to claim 1, wherein the noise determination unit determines whether or not the noise image is included in each two-dimensional elastic image constituting the elastic volume data.   The noise determination unit is based on an autocorrelation value between a pair of RF signal frame data serving as a basis of the two-dimensional elastic image, or an evaluation value obtained from an area determined to have display value in the two-dimensional elastic image. The ultrasonic diagnostic apparatus according to claim 2, wherein it is determined whether or not a noise image is included in the two-dimensional elasticity image.   The noise determination unit determines the elastic volume data as a noise volume when a ratio of the number of two-dimensional elastic images including the noise image to the number of two-dimensional elastic images constituting the elastic volume data is larger than a threshold value. The ultrasonic diagnostic apparatus according to claim 1, wherein:   The ultrasonic diagnostic apparatus according to claim 1, wherein the image display unit displays a warning mark or performs a voice warning when the three-dimensional elastic image is not displayed.   A storage unit for storing the elastic volume data or the three-dimensional elastic image, and when the elastic volume data is determined to be a noise volume by the noise determination unit, the storage unit is based on the elastic volume data or the elastic volume data; The ultrasonic diagnostic apparatus according to claim 1, wherein a three-dimensional elastic image is not read out.   When the noise determination unit determines that the elastic volume data is not a noise volume, the elastic volume data creation unit interpolates the two-dimensional elastic image including the noise image with the adjacent two-dimensional elastic image not including the noise image. The ultrasonic diagnostic apparatus according to claim 1, wherein interpolated elastic volume data is generated.   Based on the cumulative number of two-dimensional elastic images including the noise image in the elastic volume data, the ultrasonic probe moves the probe head composed of a plurality of transducers to the start position of the three-dimensional scan. The ultrasonic diagnostic apparatus according to claim 1.

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