JP2014036735A - Ultrasonic diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved technology in using an ultrasonic wave to obtain fluid vorticity.SOLUTION: A velocity vector calculation part 16 obtains a velocity vector with respect to each of multiple sample points in a coordinate system for calculation that corresponds to a space for transmitting and receiving ultrasonic waves. A vorticity calculation part 20 calculates a vorticity of an attention sample point in the coordinate system for calculation, on the basis of the velocity vector to be obtained with respect to each of the sample points in the coordinate system for calculation. The vorticity calculation part 20 calculates the vorticity at the attention sample point on the basis of the velocity vectors at the sample points around the attention sample point. A rotation calculation part 30 calculates rotation in an attention region R on the basis of each vorticity at multiple attention sample points included in the attention region. The rotation calculation part 30 adds the vorticities at all attention sample points included in the attention region and obtains the rotation in the attention region.

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to a technique for measuring a vortex of a fluid.

  It is possible to extract Doppler information from an echo signal obtained by transmitting and receiving an ultrasonic wave to a fluid such as a blood flow, and obtain fluid flow velocity information from the Doppler information. For example, Patent Document 1 discloses a technique for obtaining a two-dimensional velocity vector distribution in a cross section including a blood flow based on an echo signal obtained from the blood flow, and calculating the viscosity of the blood flow from the two-dimensional velocity vector distribution. Is described. Patent Document 1 describes that a vorticity related to a vortex generated in a blood flow is calculated from a two-dimensional velocity vector component.

JP 2006-166974 A

  In view of the background art described above, the inventor of the present application relates to a technique for measuring a fluid vortex using ultrasonic waves, particularly in an ultrasonic diagnostic apparatus for calculating an index value related to a fluid vortex. Research and development has been repeated on the typical treatment.

  The present invention has been made in the course of research and development, and an object thereof is to provide an improved technique for obtaining an index relating to the vorticity of a fluid using ultrasonic waves.

  An ultrasonic diagnostic apparatus suitable for the above-described object is obtained from a probe that transmits and receives an ultrasonic wave, a transmission / reception unit that controls transmission of the probe and obtains an ultrasonic reception signal from the region including the fluid, and the region. Based on the received signal, for a plurality of sample points in the calculation coordinate system related to the region, a velocity vector calculation unit that obtains a velocity vector for each sample point, a region of interest setting unit that sets a region of interest in the region, A circulation calculation unit that calculates the circulation in the region of interest.

  In a desirable specific example, the attention area setting section sets an attention area for calculating the circulation in the area based on setting information received from a user.

  In a desirable specific example, the circulation calculation unit adds the vorticity of all sample points of interest included in the region of interest set by the region of interest setting unit, and sets the result of the addition process as a circulation in the region of interest. It is characterized by that.

  In a preferred specific example, the circulation calculation unit calculates a circulation in the region of interest based on a blood flow velocity on the boundary of the region of interest set by the region of interest setting unit.

  In a preferred embodiment, based on a received signal obtained from the area, the flow of the fluid is visually expressed in an image forming unit that forms an ultrasonic image of the area and a display coordinate system for the ultrasonic image. The flow display forming unit for forming the flow display, the display unit for displaying the guide display image in which the flow display is superimposed on the ultrasonic image, and setting information for the vortex of the fluid are received from the user referring to the guide display image. And a user operation unit.

  In a desirable specific example, a vorticity calculation unit is further provided for calculating a vorticity for each target sample point for a plurality of target sample points included in the target region in the calculation coordinate system.

  In a preferred embodiment, the vorticity calculation unit is adjacent to the sample point of interest in the x direction within an xy plane corresponding to an ultrasound scanning plane in a calculation coordinate system represented by an xyz orthogonal coordinate system. Based on the y-direction component of the velocity vector obtained from one sample point and the x-direction component of the velocity vector obtained from two sample points adjacent in the y direction to that sample point, A z-direction component of vorticity is calculated.

  The present invention provides an improved technique for obtaining an index related to the vorticity of a fluid using ultrasonic waves.

1 is an overall configuration diagram of an ultrasonic diagnostic apparatus suitable for implementing the present invention. It is a figure for demonstrating calculation of the vorticity in a vorticity calculating part. It is a figure for demonstrating calculation of the circulation in a circulation calculating part. It is a figure which shows the vector display displayed on a display part. It is a figure which shows the streamline display displayed on a display part. It is a figure which shows the area | region display displayed on a display part.

  FIG. 1 is an overall configuration diagram of an ultrasonic diagnostic apparatus (present ultrasonic diagnostic apparatus) suitable for implementing the present invention. This ultrasonic diagnostic apparatus can measure a vortex relating to a fluid such as blood flow. Therefore, in the following, measurement of vortices related to blood flow in the heart, which is an example of a fluid to be diagnosed, is described.

  The probe 10 is an ultrasonic probe that transmits and receives ultrasonic waves in a space including the heart. The probe 10 includes a plurality of vibration elements (not shown). The plurality of vibration elements are electronically scanned and scanned with an ultrasonic beam in a space including the heart. For example, the probe 10 is used by being held by a user (examiner) and contacting the body surface of the subject. The probe 10 may be used by being inserted into the body cavity of the subject.

  The transmission / reception unit 12 functions as a transmission beam former and a reception beam former. That is, the transmission / reception unit 12 forms an ultrasonic beam by outputting a transmission signal to each of a plurality of vibration elements included in the probe 10, while adjusting a plurality of reception signals obtained from the plurality of vibration elements. Perform phase addition processing. Thereby, the ultrasonic beam is scanned in the scanning plane, an echo signal is formed along the ultrasonic beam, and is output from the transmission / reception unit 12.

  The Doppler processing unit 14 measures a Doppler shift amount included in an echo signal obtained along the ultrasonic beam. As a result, blood velocity information along the ultrasonic beam direction can be obtained.

  The velocity vector calculation unit 16 forms a two-dimensional velocity vector distribution in the scanning plane from blood flow velocity information obtained along the ultrasonic beam. Various known methods can be used to form a two-dimensional velocity vector distribution in the scanning plane from one-dimensional velocity information along the ultrasonic beam direction.

  For example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2006-166974), a two-dimensional velocity vector at each position in the scanning plane may be obtained using hydrodynamic non-compression conditions. . Alternatively, two ultrasonic beams having different directions may be formed, and velocity information may be obtained from each of the two ultrasonic beams to form a two-dimensional velocity vector.

  The velocity vector calculation unit 16 obtains a velocity vector for each sample point with respect to a plurality of sample points in a calculation coordinate system corresponding to a space in which ultrasonic waves are transmitted and received. For example, the calculation coordinate system is represented by an xyz orthogonal coordinate system, and a velocity vector is obtained for each sample point in an xy plane corresponding to the ultrasonic scanning plane to form a two-dimensional velocity vector distribution.

  The vorticity calculation unit 20 calculates the vorticity of the sample point of interest in the calculation coordinate system based on the velocity vector obtained for each sample point in the calculation coordinate system. The vorticity is one of index values related to the vortex of the blood flow.

  FIG. 2 is a diagram for explaining calculation of vorticity in the vorticity calculation unit 20 (FIG. 1). In FIG. 2, an xyz orthogonal coordinate system indicates a calculation coordinate system, and FIG. 2 shows a part of the xy plane corresponding to the scanning plane in the calculation coordinate system. In FIG. 2, a plurality of broken lines arranged in a lattice shape are shown on the xy plane, and the intersection of the broken lines and the broken lines is the position of each sample point. The sample point interval in the x direction is Δx, and the sample point interval in the y direction is Δy.

  The vorticity calculation unit 20 calculates the vorticity of the target sample point P based on the velocity vectors at the plurality of sample points P1 to P4 around the target sample point P. In the specific example of FIG. 2, the sample point P of interest is at coordinates (x, y), the sample point P1 is at coordinates (x + 1, y), the sample point P2 is at coordinates (x, y + 1), and the sample point P3 Is at coordinates (x-1, y), and the sample point P4 is at coordinates (x, y-1).

The vorticity calculation unit 20 includes y-direction components V (x + 1, y) and V (x−1, y) of velocity vectors obtained from the sample points P1 and P3 adjacent to the sample point P in the x direction. And x direction components U (x, y + 1) and U (x, y-1) of velocity vectors obtained from sample points P2 and P4 adjacent to the sample point P in the y direction, The z-direction component ω _z of the vorticity at the sample point P of interest is calculated using the following equation.

Note that the z-direction component ω _z of the vorticity is a component of rotational motion around the arrow along the z direction as shown in FIG. 2. For example, the counterclockwise rotation direction shown in FIG. The rotation direction is the clockwise direction, which is the opposite direction, and the negative rotation.

  Returning to FIG. 1, the circulation calculation unit 30 calculates the circulation, which is another index value regarding the vortex of the blood flow, based on the vorticity calculated by the vorticity calculation unit 20.

  FIG. 3 is a diagram for explaining calculation of circulation in the circulation calculation unit 30 (FIG. 1). FIG. 3 shows a part of the xy plane corresponding to the scanning plane in the calculation coordinate system which is an xyz orthogonal coordinate system, as in FIG. Also in FIG. 3, the xy plane shows a plurality of broken lines arranged in a lattice pattern, and the intersection of the broken lines and the broken lines is the position of each sample point. The sample point interval in the x direction is Δx, and the sample point interval in the y direction is Δy.

Prior to the calculation of the circulation, the vorticity calculation unit 20 (FIG. 1) determines the vorticity ω _z (i, j) for each target sample point for a plurality of target sample points included in the target region R in the calculation coordinate system. Is calculated. Then, the circulation calculation unit 30 (FIG. 1) calculates the circulation in the attention area R based on the vorticity ω _z (i, j) of a plurality of attention sample points included in the attention area R.

The circulation calculation unit 30 adds vorticity ω _z (i, j) of all sample points of interest included in the region of interest R to obtain Γ, which is a circulation in the region of interest R, as shown in the following equation. .

Σ in Equation 2 means the sum of all the target sample points included in the target region R. Note that, as will be described later, the attention area R is preferably, for example, circular or elliptical according to the shape of the vortex. Therefore, as shown in FIG. 3, the approximate region R ′ obtained by approximating the circular or elliptical attention region R according to the position of the sample point is used, and the vortices of all the attention sample points included in the approximation region R ′. The degree ω _z (i, j) may be added to calculate Γ in equation (2).

Further, the circulation calculation unit 30 may obtain Γ, which is a circulation, by the following equation that circulates and integrates the blood flow velocity v in the tangential direction of the closed curve C along the closed curve C that is the boundary of the region of interest R.

  Returning to FIG. 1, the ultrasonic image forming unit 18 forms a B-mode image corresponding to the scanning plane based on an echo signal obtained along the ultrasonic beam in the scanning plane. That is, a B-mode image showing a cross section in the heart is formed.

  The flow display forming unit 40 visually represents the blood flow in the B-mode image display coordinate system based on the velocity vector obtained for each sample point of the calculation coordinate system in the velocity vector calculation unit 16. Form a flow display. Then, a guide display image obtained by superimposing a flow display on the B-mode image showing a cross section in the heart is displayed on the display unit 50. Therefore, vector display and streamline display, which are specific examples of the guide display image, will be described.

  FIG. 4 is a diagram showing a vector display 52 displayed on the display unit 50 (FIG. 1). The vector display 52 displays a plurality of arrows V corresponding to velocity vectors on a B-mode image showing a heart muscle and a cross section inside the heart. The direction of each arrow V corresponds to the direction of the velocity vector at the position of the arrow V, and the length of each arrow V corresponds to the magnitude of the velocity vector at the position of the arrow V.

  The plurality of arrows V are obtained from the velocity vector calculated in the velocity vector calculation unit 16 (FIG. 1). In the velocity vector calculation unit 16, a velocity vector is obtained for each sample point in the calculation coordinate system. On the other hand, the plurality of arrows V in the vector display 52 of FIG. 4 are arranged at a plurality of display sample points in the display coordinate system of the B-mode image.

  The position of each sample point in the calculation coordinate system and the position of each display sample point in the display coordinate system do not necessarily match each other. The display sample point interval in the coordinate system is larger.

  Therefore, the flow display forming unit 40 (FIG. 1) obtains the display sample point from the velocity vector of one or more sample points in the calculation coordinate system in the vicinity of each display sample point in the display coordinate system by interpolation processing or the like. Is calculated, and an arrow V is formed at the display sample point in accordance with the magnitude and direction of the calculated velocity vector.

  From the vector display 52 shown in FIG. 4, the user (examiner) can visually check the flow of blood flow in the heart. For example, a plurality of arrows V are displayed side by side in a circle. In addition, it can be confirmed that there is a blood flow vortex.

  FIG. 5 is a diagram showing the streamline display 54 displayed on the display unit 50 (FIG. 1). The streamline display 54 displays a streamline L obtained on the basis of the velocity vector on a B-mode image showing a cross section of the heart and the heart.

  For example, the streamline L is drawn from the start point set at an arbitrary position in the B-mode image so that the tangent line coincides with the direction of the velocity vector of the blood flow. In FIG. 5, the streamline L is indicated by a broken line, but may be indicated by a solid line, other lines, or may be colored.

  Also from the streamline display 54 shown in FIG. 5, the user (examiner) can visually confirm the flow of blood flow in the heart. For example, at the location where the streamline L is displayed in a circle. It can be confirmed that there is a vortex of blood flow.

  Returning to FIG. 1, when the vector display 52 (FIG. 4) or streamline display 54 (FIG. 5) is displayed on the display unit 50, the user (inspector) visually confirms the vector display 52 or streamline display 54. Then, the setting information of the region of interest R (FIG. 3) is input to the place considered to be the vortex of the blood flow, for example, using the operation device 62. The attention area setting unit 60 sets the attention area R based on the setting information received from the user.

  FIG. 6 is a diagram showing an area display 56 displayed on the display unit 50 (FIG. 1). The region display 56 is a region of interest R (R1 to R3) displayed on a B-mode image showing a cross section of the heart and the heart. FIG. 6 shows an example in which three attention regions R1 to R3 are set.

  A user (examiner) who confirms the flow of blood flow by looking at the vector display 52 (FIG. 4) or the streamline display 54 (FIG. 5), for example, seems to be a vortex of the blood flow on the vector display 52 or the streamline display 54. Specify the location. The designated location is set to the center point of the attention area R, for example. Then, the user sets the radius of the attention area R, and thereby, for example, the attention area R1 shown in FIG. 6 is set. Similarly, attention areas R2 and R3 and a plurality of attention areas R may be set as necessary. In addition, an elliptical area may be set like attention area R3 shown in FIG. 6, or an area other than a circle or an ellipse may be set.

  The area display 56 also displays setting information related to the attention area R. In FIG. 6, center coordinates for each of the three attention regions R1 to R3 are displayed. For example, center coordinates (x, y) for each of the attention areas R1 to R3 are displayed with the transmission start point of the ultrasonic wave as the origin O. Furthermore, the length of the radius for each of the attention regions R1 to R3 may be displayed.

  Thus, for example, when a plurality of attention regions R are set, the circulation described with reference to FIG. 3 is calculated for each attention region R. Then, the circulation value calculated for each attention area R is displayed numerically together with the area display 56 of FIG. 6, for example. Of course, a dedicated display screen for displaying the circulation value may be formed.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above is only a mere illustration in all the points, and does not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof.

  DESCRIPTION OF SYMBOLS 10 probe, 16 speed vector calculating part, 20 vorticity calculating part, 30 circulation calculating part, 40 flow display formation part, 60 attention area setting part.

Claims (7)

A probe for transmitting and receiving ultrasound,
A transmission / reception unit that obtains an ultrasonic reception signal from within a region containing fluid by controlling transmission of the probe;
Based on a received signal obtained from within the region, a speed vector computing unit that obtains a velocity vector for each sample point for a plurality of sample points in the computation coordinate system related to the region;
An attention area setting section for setting an attention area within the area;
A circulation calculation unit for calculating the circulation in the region of interest;
Having
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The region of interest setting unit sets a region of interest for calculating the circulation in the region based on setting information received from a user.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1 or 2,
The circulation calculation unit adds the vorticity of all sample points of interest included in the region of interest set by the region of interest setting unit, and sets the result of the addition process as a circulation in the region of interest.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1 or 2,
The circulation calculation unit calculates the circulation in the region of interest based on the blood flow velocity on the boundary of the region of interest set by the region of interest setting unit.
An ultrasonic diagnostic apparatus. In the ultrasonic diagnostic apparatus according to any one of claims 1 to 4,
An image forming unit that forms an ultrasonic image of the region based on a reception signal obtained from the region;
In the coordinate system for displaying ultrasonic images, a flow display forming unit that forms a flow display that visually represents the flow of the fluid,
A display unit for displaying a guide display image in which a flow display is superimposed on an ultrasonic image;
A user operation unit for receiving setting information for a fluid vortex from a user who refers to a guide display image;
Further having
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to any one of claims 1 to 5,
A vorticity calculation unit that calculates vorticity for each target sample point for a plurality of target sample points included in the target region in the calculation coordinate system;
Further having
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 6,
The vorticity calculation unit is obtained from two sample points adjacent to the target sample point in the x direction within an xy plane corresponding to the ultrasonic scanning plane in the calculation coordinate system represented by the xyz orthogonal coordinate system. Z direction of the vorticity at the sample point of interest based on the y direction component of the velocity vector obtained and the x direction component of the velocity vector obtained from two sample points adjacent to the sample point of interest in the y direction Calculate ingredients,
An ultrasonic diagnostic apparatus.

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