JP6518130B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to a technique for diagnosing blood flow in the heart.

  There is known a technique for obtaining movement information (motion information) of blood flow from a received signal obtained by transmitting and receiving ultrasonic waves to the blood flow. For example, Patent Document 1 discloses a technique for obtaining a two-dimensional velocity vector of a fluid at a plurality of points in an observation plane based on received signals obtained by transmitting and receiving ultrasonic waves to and from fluid such as blood flow in a living body. Is described. The distribution of two-dimensional velocity vectors at a plurality of points in the observation plane makes it possible to obtain diagnostic information such as streamlines indicating fluid flow, and is expected to be applied to, for example, diagnosis of the heart and the like.

  Further, Patent Document 2 discloses an ultrasonic diagnostic apparatus that forms an image in which blood flow in a living body is expressed as motion of a plurality of display elements. A virtual particle of blood flow is suitable as each display element, and the device described in Patent Document 2 has determined the position of the particle in the next frame based on the velocity vector in the current frame of each particle ), And displays, for example, the trajectories of each particle obtained by tracking the moving destinations of each particle over a plurality of frames. This makes it possible to visually and intuitively confirm, for example, the state of eddy current, turbulent flow, stagnation, etc. in the blood flow.

Unexamined-Japanese-Patent No. 2013-192643 JP 2008-73279 A

  The techniques described in Patent Documents 1 and 2 are ground-breaking technologies that are extremely useful for practical use in obtaining blood flow movement information (exercise information), and further applications and improvements of these techniques are possible. Is expected. In particular, application to the diagnosis of blood flow in the heart is expected.

  By the way, the heart in a living body repeats expansion and contraction movement, and the blood flow in the heart is complicatedly changed by the expansion and contraction movement. Therefore, in the past, attempts have been made to express the state of complicatedly changing blood flow appropriately in an easy-to-understand manner.

  The present invention has been made in view of the background art described above, and its object is to provide a new display mode that expresses the state of blood flow in the heart.

  An ultrasonic diagnostic apparatus suitable for the above purpose includes a vector operation unit for obtaining a blood flow vector of blood flow in the heart chamber of the heart based on signals obtained by transmitting and receiving ultrasonic waves, and blood in the heart chamber. A particle generation unit that generates a plurality of virtual particles in a flow, a particle operation unit that derives a movement destination of each particle based on the blood flow vector, and a blood flow in which the movement destinations of the plurality of particles are linked to one another And an image forming unit for forming an image.

  In the above configuration, the blood flow vector is vector information on motion of the blood flow, and for example, a velocity vector indicating the velocity and direction at each coordinate (each blood flow portion) in the blood flow, or each coordinate in the blood flow The movement vector and the movement vector indicating the direction are preferable specific examples. The blood flow vector can be obtained, for example, using the technique described in Patent Document 1 (Japanese Patent Laid-Open No. 2013-192643), that is, although it can be obtained using a two-dimensional velocity vector distribution, other known techniques are used. Blood flow vectors may be obtained.

  In addition, each virtual particle of blood flow is a virtual element in operation used to analyze blood flow (flow of blood), and, for example, a plurality of virtual particles in blood flow to be diagnosed. Particles are produced.

  Furthermore, in the above configuration, a blood flow image is formed in which the destinations of the plurality of particles are linked to one another. For example, a blood flow image is formed by a display mode in which destinations of a plurality of particles are closely associated with each other. Specifically, although a blood flow image in which the moving destinations of the plurality of particles are linked to one another by a line passing through a plurality of positions corresponding to the moving destinations of the plurality of particles is suitable, the plurality of particles are displayed Destinations of may be linked to each other.

  And according to the apparatus provided with the said structure, the blood flow image of the new display aspect which tied and showed the moving-destination of several particle mutually is provided. With this blood flow image, it is possible for a user such as a doctor or a laboratory technician to intuitively grasp, for example, which part of a plurality of particles has reached which part in the heart, etc. Become.

  In a desirable embodiment, the image forming unit is a blood flow image in which the moving destinations of the plurality of particles are shown by connecting the plurality of moving destinations by showing the line passing through a plurality of positions corresponding to the moving destinations of the plurality of particles. To form.

  In a desirable embodiment, the image forming unit forms the blood flow image in which a line portion corresponding to the moving destination of each particle on the line is expressed in a color corresponding to a position at which each particle is generated. It is characterized by

  In a desirable embodiment, the image forming unit forms the line passing through a plurality of positions corresponding to destinations of the plurality of particles in the time phase for each time phase over a plurality of time phases. Do.

  In a desirable embodiment, the image forming unit forms a graph indicating the distance from the generation position of the particles to the movement destination for each particle of the plurality of particles.

  In a desirable embodiment, the image forming unit forms the graph in which the generation position of each particle is indicated on one axis and the distance of each particle is indicated on the other axis.

  In a desirable embodiment, the image forming unit forms the graph in which the distance of each particle is expressed in a color according to the position where each particle is generated.

  The present invention provides a new display mode that expresses the state of blood flow in the heart. For example, according to a preferred embodiment of the present invention, a blood flow image of a new display mode in which destinations of a plurality of particles are linked to one another is shown, whereby a user such as a doctor or a laboratory technician can It is possible to visually and intuitively grasp which particles of the particles have reached to which portion in the heart.

It is a figure which shows the whole structure of the ultrasonic diagnosing device suitable in implementation of this invention. It is a figure which shows the example of the region of interest corresponding to a cardiac lumen. It is a figure which shows the other specific example of an inflow line and an outflow line. It is a figure which shows the specific example of speed vector distribution. It is a figure for demonstrating a flame | frame row | line. It is a figure for demonstrating the interpolation process between frames. It is a figure for demonstrating the production | generation of several particle | grains. It is a figure for demonstrating the specific example of the calculation of the movement destination of each particle | grain. It is a figure for demonstrating exception processing of operation of the movement place of each particle. It is a figure for demonstrating the completion | finish conditions of calculation of the movement destination of each particle | grain. It is a figure which shows the example of a wave front line. It is a figure which shows the specific example of a blood-flow display image. It is a figure which shows the blood-flow display image of a healthy example and a disease example. It is a figure which shows the specific example of a particle | grain distance graph. It is a figure for demonstrating the specific example of the coloring process according to the production | generation position.

  FIG. 1 is an overall block diagram of an ultrasonic diagnostic apparatus suitable for practicing the present invention. The ultrasonic diagnostic apparatus of FIG. 1 has a function of acquiring movement information of blood flow (blood flow), and is particularly suitable for diagnosing blood flow in the heart of a living body.

  The probe 10 is an ultrasonic probe that transmits and receives ultrasonic waves to a region including a diagnostic target such as a heart in a living body, for example. The probe 10 includes a plurality of vibrating elements, and the plurality of vibrating elements are electronically scan-controlled to scan an ultrasonic beam in a space including the heart. For example, the probe 10 is held by a user (examiner) such as a doctor and used in contact with a body surface of a subject. The probe 10 may be inserted into a body cavity of a subject and may be used, or may be a probe in which an electronic scan and a mechanical scan are combined. As the probe 10, for example, a convex type is preferable, but a sector type, a linear type, or the like may be used.

  The transmission / reception unit 12 has functions as a transmission beamformer and a reception beamformer. That is, the transmission / reception unit 12 forms a transmission beam by outputting a transmission signal to each of the plurality of transducer elements included in the probe 10, and further, for a plurality of received wave signals obtained from the plurality of transducer elements. The reception beam is formed by performing phasing addition processing and the like. As a result, the ultrasound beams (the transmission beam and the reception beam) are scanned in the scan plane, and a reception signal corresponding to the ultrasound beam is formed.

  In addition, in the transmission / reception unit 12, detection processing, filter processing, AD conversion processing, and the like may be performed on the reception signal of the ultrasonic waves. In addition, in order to obtain an ultrasonic reception signal, an ultrasonic beam may be three-dimensionally scanned in a third-order space, or a technique such as transmission aperture synthesis may be used.

  The ultrasonic image forming unit 20 forms data (image data) of an ultrasonic image based on a reception signal of ultrasonic waves obtained from the inside of a scanning plane. The ultrasound image forming unit 20 forms frame data for a B-mode image, for example, based on a received signal of ultrasound that has been subjected to detection processing, filter processing, AD conversion processing, and the like. Of course, image data related to a known ultrasound image other than the B mode image may be formed.

  The Doppler processing unit 30 measures the amount of Doppler shift included in the received signal corresponding to the ultrasonic beam. The Doppler processing unit 30 measures, for example, a Doppler shift generated in the received signal of the ultrasonic wave by the blood flow by known Doppler processing, and obtains velocity information (doppler information) of the ultrasonic beam direction about the blood flow.

  The velocity vector calculator 40 forms a two-dimensional distribution of velocity vectors in the scanning plane from the velocity information in the ultrasonic beam direction of the blood flow. For example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-192643), the velocity vector computing unit 40 uses motion information of the heart wall in addition to velocity information in the ultrasonic beam direction for blood flow. Thus, a two-dimensional velocity vector of blood flow at each position in the scan plane is obtained.

  In order to form a two-dimensional velocity vector distribution in the scanning plane using one-dimensional velocity information along the ultrasonic beam direction, various known methods can be used. Of course, 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 40 obtains a velocity vector for each sample point for a plurality of sample points in the calculation coordinate system corresponding to the space in which the ultrasonic waves are transmitted and received. For example, the coordinate system for calculation is represented by the xyz orthogonal coordinate system, and in the xy plane corresponding to the scan plane of ultrasonic waves, velocity vectors are obtained for each sample point to form a two-dimensional distribution of velocity vectors. Note that a two-dimensional distribution of velocity vectors may be formed in a scanning coordinate system corresponding to ultrasound scanning, for example, an rθ coordinate system according to the beam depth direction r and the beam scanning direction θ.

  The velocity vector calculation unit 40 generates vector frames each showing a distribution of a two-dimensional velocity vector composed of velocity vectors corresponding to a plurality of sample points (plural coordinates). Also, the velocity vector calculation unit 40 generates a plurality of vector frames one after another over a plurality of time phases.

  The lumen line setting unit 42 sets a lumen line to be an outer edge of the heart lumen in the image data obtained by the processing by the ultrasound imaging unit 20. Further, the inflow / outflow line setting unit 44 sets an inflow line in the flow path of the blood flow into the heart lumen in the image data, and sets an outflow line in the flow path of the blood flow out of the heart lumen. Then, a region surrounded by the lumen line, the inflow line, and the outflow line is taken as a region of interest.

  FIG. 2 is a diagram showing a specific example of a region of interest corresponding to a cardiac lumen. FIG. 2 shows a specific example of the image data 22 obtained in the ultrasound image forming unit 20. In the image data 22 of FIG. 2, the lumen of the left ventricle surrounded by the myocardium and the valve is shown. (Heart chamber) is included.

  The lumen line 52 is formed based on a plurality of trace points corresponding to the outer edge of the heart chamber (e.g., the lumen of the left ventricle). For example, a display image corresponding to the image data 22 is displayed on the display unit 82, and a user such as a doctor uses the operation device 90 while looking at the display image, Set a trace reference point (which may be several). In addition, the lumen line setting unit 42 adds a plurality of trace points between the trace reference points by, for example, interpolation processing based on the trace reference points set by the user.

  Then, the lumen line setting unit 42 forms the lumen line 52 based on a plurality of sample points (for example, about 100 points) consisting of several trace reference points and a plurality of added trace points. For example, a lumen line 52 is formed to connect a plurality of sample points to one another. The boundary of the heart chamber and the myocardium may be identified by image processing such as binarization processing on the image data 22, and the lumen line 52 may be formed along the boundary.

  The inflow line 54 and the outflow line 56 are set by the inflow / outflow line setting unit 44 according to the operation from the user. For example, while looking at the display image corresponding to the image data 22, a user such as a doctor specifies the positions of the start point S and the end point E of the inflow line 54 and the outflow line 56, respectively. For example, these four points are set in the order of start point S and end point E of the inflow line 54 and start point S and end point E of the outflow line 56.

  When the positions of start point S and end point E of the inflow line 54 and the outflow line 56 are set by the user, the inflow / outflow line setting unit 44 connects the inflow line 54 to connect the lumen line 52 and the inflow line 54. Set up and set the outflow line 56 to connect the lumen line 52 and the outflow line 56.

  For example, the inflow / outflow line setting unit 44 moves the start point S of the inflow line 54 to the position of the sample point (trace point or trace reference point) on the lumen line 52 closest to the start point S. The end point E is moved to the position of the sample point (trace point or trace reference point) on the lumen line 52 closest to the end point E.

  Further, the inflow / outflow line setting unit 44 moves the start point S of the outflow line 56 to the position of the sample point (trace point or trace reference point) on the lumen line 52 closest to the start point S. The end point E is moved to the position of the sample point (trace point or trace reference point) on the lumen line 52 closest to the end point E. Preferably, a straight line or a curve connecting the end point E of the inflow line 54 and the start point S of the outflow line 56 is formed.

  Thus, an area surrounded by the lumen line 52, the inflow line 54 and the outflow line 56 is formed, and the area is taken as the area of interest. In addition, although the specific example which makes the inflow line 54 and the outflow line 56 straight in FIG. 2, lines other than a straight line may be utilized.

  FIG. 3 is a view showing another specific example of the inflow line 54 and the outflow line 56. As shown in FIG. For example, as shown in FIG. 3 (A), when the lumen line 52 of the closed curve is obtained, as shown in FIG. 3 (B), the start point S and the end point E A curved inflow line 54 and an outflow line 56 may be formed along the line.

  Returning to FIG. 1, the lumen line velocity calculator 46 calculates the velocity information of the myocardium (heart wall) on the lumen line (symbol 52 in FIG. 2) based on the image data formed in the ultrasound image forming unit 20. Generate The lumen line velocity calculating unit 46 generates myocardial velocity information for each sample point for a plurality of sample points on the lumen line.

  The lumen line speed calculating unit 46 performs, for example, pattern matching using correlation calculation based on pixel values (such as luminance values) of image data between frames of image data of ultrasound images obtained over a plurality of frames. For each sample point on the lumen line, the movement position of the sample point is tracked in a two-dimensional plane over a plurality of frames. Thereby, two-dimensional movement information is obtained for each sample point, and, for example, a two-dimensional velocity vector is calculated based on the movement amount (movement vector) between the frames and the time between the frames. If the image data is data corresponding to the xy orthogonal coordinate system, a velocity vector in the xy orthogonal coordinate system is calculated, and if the image data is data corresponding to the rθ coordinate system, a velocity vector in the rθ coordinate system is calculated .

  Also, the tracking result of each sample point on the lumen line by the lumen line speed calculating unit 46 is sent to the lumen line setting unit 42, and the lumen line setting unit 42 follows the movement of the plurality of sample points. Change the shape of the lumen line.

  Furthermore, the start point S and the end point E (see FIG. 2) of the inflow line 54 and the outflow line 56 respectively follow the movement of the corresponding sample points (each sample point on the lumen line). Thus, the inflow line 54 and the outflow line 56 are set by the inflow / outflow line setting unit 44 in accordance with the change in the shape of the lumen line, that is, the movement of the heart in the image data.

  When obtaining a two-dimensional velocity vector of blood flow in the velocity vector computing unit 40 by the method described in Patent Document 1, motion information of the heart wall is used. In this case, motion of the heart wall is used. As information, the velocity vector at each sample point on the lumen line calculated by the lumen line velocity calculator 44 is used.

  The processes and functions of the interpolation processing unit 50, the particle generation unit 60, and the particle operation unit 70 will be described in detail later with reference to the drawings. The display image forming unit 80 forms a blood flow display image based on the image data of the ultrasonic image obtained from the ultrasonic image forming unit 20 and the calculation result obtained from the particle calculating unit 70. The blood flow display image formed in the above is displayed on the display unit 82.

  The control unit 100 generally controls the inside of the ultrasonic diagnostic apparatus of FIG. In the overall control by the control unit 100, an instruction received from a user such as a doctor or a laboratory technician is also reflected via the operation device 90.

  Of the configuration shown in FIG. 1 (each part denoted by reference numerals), the transmitting / receiving unit 12, the ultrasonic image forming unit 20, the Doppler processing unit 30, the velocity vector calculating unit 40, the lumen line setting unit 42, and the inflow / outflow line setting unit 44. The lumen line speed calculating unit 46, the interpolation processing unit 50, the particle generating unit 60, the particle calculating unit 70, and the display image forming unit 80 are realized by using hardware such as an electric and electronic circuit or a processor. Devices, such as a memory, may be used as necessary in the implementation. In addition, at least a part of the functions corresponding to the above-described units may be realized by a computer. That is, at least a part of the functions corresponding to the above-described units may be realized by cooperation of hardware such as a CPU, a processor, or a memory, and software (program) defining operations of the CPU or the processor.

  A preferable specific example of the display unit 82 is a liquid crystal display or the like, and the operation device 90 can be realized by, for example, at least one of a mouse, a keyboard, a trackball, a touch panel, and other switches. The control unit 100 can be realized, for example, by cooperation of hardware such as a CPU, a processor, and a memory, and software (program) that defines the operation of the CPU and the processor.

  The overall configuration of the ultrasonic diagnostic apparatus of FIG. 1 is as described above. Next, a specific example of the function realized by the ultrasonic diagnostic apparatus of FIG. 1 will be described in detail. In addition, about the structure (each part which attached the code | symbol) shown in FIG. 1, the code | symbol of FIG. 1 is utilized in the following description.

  FIG. 4 is a diagram showing a specific example of the velocity vector distribution. For example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-192643), the velocity vector calculation unit 40 performs scanning using the velocity information in the ultrasonic beam direction of the blood flow and the motion information of the heart wall. Obtain a two-dimensional velocity vector of blood flow at each position in the plane. Specifically, based on velocity information (doppler information) in the ultrasonic beam direction obtained from the Doppler processing unit 30 and velocity information at each sample point on the lumen line 52 obtained from the lumen line velocity calculating unit 46 For example, the velocity vector distribution shown in FIG. 4 is formed.

  The velocity vector distribution shown in FIG. 4 is expressed by the xy coordinate system (orthogonal coordinate system) including the lumen line 52 of the heart (see FIG. 2), and a plurality of velocities calculated at plural coordinates in the xy coordinate system It is composed of a vector (velocity vector of blood flow) V. The velocity vector calculator 40 forms, for example, a two-dimensional velocity vector distribution in a scanning coordinate system corresponding to ultrasound scanning, for example, in the rθ coordinate system according to the beam depth direction r and the beam scanning direction θ, Coordinate conversion processing is performed to obtain velocity vector distribution in the xy coordinate system shown in FIG.

  The velocity vector computing unit 40 generates vector frames each composed of velocity vectors V corresponding to a plurality of sample points (plural coordinates), that is, vector frames indicating a two-dimensional velocity vector distribution. The velocity vector calculator 40 generates a plurality of vector frames one after another over a plurality of time phases. Thereby, a vector frame sequence consisting of a plurality of vector frames is obtained.

  FIG. 5 is a diagram for explaining a frame sequence, and FIG. 5A shows a specific example of a vector frame sequence. In the specific example shown in FIG. 5A, the vector frame sequence is composed of a plurality of vector frames (1 to 5 are representatively shown).

  Each vector frame composed of velocity vectors at multiple coordinates is generated using velocity information (doppler information) in the ultrasonic beam direction obtained from the Doppler processing unit 30. When obtaining Doppler information, for example, transmission and reception of the color Doppler method is used to transmit and receive ultrasound information in the same beam direction repeatedly, so that the transmitting and receiving frame rate in the case of obtaining Doppler information as compared to, for example, Will be lower. Since the velocity vectors constituting each vector frame are calculated using Doppler information, the frame rate of the vector frame sequence is also relatively low.

  Therefore, the inter-frame interpolation process is performed by the interpolation processing unit 50 on the vector frame sequence. FIG. 5B shows a specific example of the frame sequence after interpolation subjected to the interframe interpolation process. In the example shown in FIG. 5 (B), the frame sequence after correction is added between the vector frames and a plurality of vector frames (1 to 5 representatively shown in FIG. 5 (A)). Composed of a plurality of interpolation frames. Each interpolation frame is generated by applying a velocity vector-based interpolation process between two vector frames adjacent to each other.

  The frame rate of the frame sequence after interpolation may be determined, for example, according to the display frame rate on the display unit 82. Specifically, for example, if the display frame rate is 60 Hz, the number of interpolation frames to be added is determined so that the frame rate of the frame sequence after interpolation is also 60 Hz. Of course, the display frame rate and the frame rate of the frame sequence after interpolation do not necessarily have to match.

  FIG. 6 is a diagram for explaining an inter-frame interpolation process. The interpolation processing unit 50 applies an interpolation process between two vector frames adjacent to each other in a vector frame sequence (see FIG. 5) consisting of a plurality of vector frames, and one or more interpolation frames between the vector frames. to add. Each interpolation frame is composed of interpolation vectors at a plurality of coordinates.

  The interpolation processing unit 50 calculates an interpolation vector corresponding to the coordinates by interpolation based on two velocity vectors corresponding to the coordinates obtained from two vector frames adjacent to each other for each coordinate.

  FIG. 6 shows a specific example of inter-frame interpolation processing at coordinates (x, y). In FIG. 6, vector frame (n) and vector frame (n + 1) are two vector frames adjacent to each other in a vector frame sequence. In the specific example shown in FIG. 6, four interpolation frames (1) to (4) are added at equal intervals between the vector frame (n) and the vector frame (n + 1). The time interval between the vector frame (n) and the vector frame (n + 1) is ΔT, and four interpolation frames (1) to (4) are added at equal intervals Δt within ΔT. Therefore, ΔT = 5 × Δt.

  The interpolation processing unit 50 calculates, for example, interpolation vectors constituting each interpolation frame by linear interpolation according to a time interval. For example, the velocity vector (x-direction component, y-direction component) at coordinates (x, y) in vector frame (n) is (Vx0, Vy0), and at coordinates (x, y) in vector frame (n + 1) When the velocity vector (x-direction component, y-direction component) is (Vx1, Vy1), the x-direction component of the interpolation vector at each coordinate (x, y) of the interpolation frames (1) to (4) and the y direction The components are calculated by Equations 1 to 4 respectively.

[Equation 1]
Interpolation vector at coordinate (x, y) of interpolation frame (1) x direction component = {(Vx 0 · 4 Δt) + (Vx 1 · Δt)} / 5 Δt
y-direction component = {(Vy 0 · 4 Δt) + (Vy 1 · Δt)} / 5 Δt
[Equation 2]
Interpolation vector at coordinates (x, y) of interpolation frame (2) x direction component = {(Vx 0 · 3 Δt) + (Vx 1 · 2 Δt)} / 5 Δt
y-direction component = {(Vy0.3.t) + (Vy1.2.t)} / 5Δt
[Equation 3]
Interpolation vector at coordinates (x, y) of interpolation frame (3) x direction component = {(Vx 0 · 2 Δt) + (Vx 1 · 3 Δt)} / 5 Δt
y-direction component = {(Vy0.2.DELTA.t) + (Vy1.3.DELTA.t)} / 5.DELTA.t
[Equation 4]
Interpolation vector at the coordinates (x, y) of the interpolation frame (4) x direction component = {(Vx0 · Δt) + (Vx1 · 4Δt)} / 5Δt
y direction component = {(Vy0 · Δt) + (Vy1 · 4Δt)} / 5Δt

  Equations 1 to 4 are only one specific example in the case of using linear interpolation according to a time interval, and linear interpolation may be realized using other equations, or linear interpolation An interpolation vector may be calculated using interpolation processing other than that. Furthermore, when calculating an interpolation vector at each coordinate, a velocity vector other than the coordinate, for example, near the coordinate may be referred to. Also, for example, in interpolation processing between vector frame (n) and vector frame (n + 1), velocity vectors within vector frames near these two vector frames other than these two vector frames may be used, for example. Good.

  The interpolation processing unit 50 performs inter-frame interpolation processing for each of the plurality of coordinates for which the velocity vector distribution is obtained to obtain an interpolation vector, thereby forming each interpolation frame composed of interpolation vectors in the plurality of coordinates. Do. In this way, a post-interpolation frame sequence (see FIG. 5B) composed of a plurality of vector frames and a plurality of interpolation frames added between the vector frames is obtained. Then, based on the post-interpolation frame sequence, virtual multiple particle movement destinations related to blood flow are calculated. A plurality of virtual particles are generated by the particle generator 60.

  FIG. 7 is a diagram for explaining generation of a plurality of particles. The particle generation unit 60 sets a plurality of particles related to the blood flow in the coordinate system including the blood flow, that is, in the coordinate system in which the ultrasonic image and the two-dimensional velocity vector distribution are formed. The particle generator 60 generates, for example, a plurality of particles on an inflow line 54 set for the heart in an ultrasound image. In this case, the inflow line 54 is a production line for producing a plurality of particles.

  For example, as in the basic example shown in FIG. 7, a plurality of particles arranged in an example at equal intervals are generated on the inflow line 54 connecting the start point S and the end point E by a straight line. For example, 50 particles are generated on the inflow line 54 at equal intervals. When the length of the inflow line 54 is 50 pixels or less, one particle is generated per one pixel on the inflow line 54. Of course, a plurality of particles may be generated with a set number other than 50. The user may set or change the number of particles.

  It is desirable that the particle generation unit 60 generate a plurality of particles in only one specific frame (only one time phase). The particle generation unit 60 generates a plurality of particles, for example, in the first frame that is the starting point of the calculation. The particle generation unit 60 may generate a plurality of particles in each frame periodically over a plurality of frames. For example, a plurality of particles may be generated in each frame at intervals of several frames to the extent that the visibility of the blood flow display image described later is not impaired.

  When a plurality of particles are generated by the particle generation unit 60, the particle operation unit 70 calculates the movement destination of each particle for each particle based on the corrected frame sequence (FIG. 5 (B)).

  FIG. 8 is a diagram for describing a specific example of calculation of the movement destination of each particle. FIG. 8 is based on a corrected frame sequence (see FIG. 6) in which four interpolation frames (1) to (4) are added at equal intervals between the vector frame (n) and the vector frame (n + 1). , A specific example of the operation regarding one particle P is shown.

  When the particle P exists at the position P0 (coordinate P0) in the vector frame (n), for example, when the particle P is generated at the position P0 in the vector frame (n), first, the velocity vector of blood flow at the position P0 V0 is used. If there is a velocity vector of coordinates corresponding to the position P0 (coordinate P0) among the velocity vectors of plural coordinates constituting the vector frame (n), the velocity vector is set as the velocity vector V0. If there is no velocity vector of coordinates corresponding to the position P0, the velocity vector V0 is calculated by linear interpolation processing (intra-frame interpolation processing) or the like based on velocity vectors of plural coordinates in the vicinity of the position P0.

  Then, by multiplying the velocity vector V0 by the frame interval Δt (see FIG. 6), a movement vector (the magnitude is Δt times the velocity vector V0 and the same direction as the velocity vector V0) is calculated, and only the movement vector is calculated from the position P0. The moved position P1 (coordinate P1) is derived. The position P1 thus obtained is the position (coordinate of the movement destination) of the particle P in the interpolation frame (1) which is the next frame (next phase) of the vector frame (n).

  Next, the velocity vector V1 of the blood flow at the position P1 is used. If there is an interpolation vector of coordinates corresponding to the position P1 (coordinate P1) among the interpolation vectors of plural coordinates constituting the interpolation frame (1), the interpolation vector is regarded as the velocity vector V1 and coordinates corresponding to the position P1 If there is no interpolation vector, the velocity vector V1 is calculated by linear interpolation processing (intra-frame interpolation processing) or the like based on interpolation vectors of a plurality of coordinates near the position P1.

  Then, by multiplying the velocity vector V1 by the frame interval Δt, a movement vector (the magnitude is Δt times the velocity vector V1 and the same direction as the velocity vector V1) is calculated, and the position P2 is moved from the position P1 by the movement vector Coordinates P2) are derived. The position P2 obtained by this becomes the position (coordinate of the movement destination) of the particle P in the interpolation frame (2) which is the next frame (next time phase) of the interpolation frame (1).

  The same process as described above is performed on the interpolation frame (3) and the interpolation frame (4) following the interpolation frame (2). That is, the coordinates of the movement destination of the particle P are calculated based on the movement vector obtained by multiplying the velocity vector (V2, V3) at the position of the particle P by the frame interval Δt. In the specific example of FIG. 8, the position P3 in the interpolation frame (3) and the position P4 in the interpolation frame (4) are the coordinates of the movement destination of the particle P.

  Furthermore, the velocity vector V4 of the blood flow at the position P4 is used. If there is an interpolation vector of coordinates corresponding to the position P4 (coordinate P4) among the interpolation vectors of plural coordinates constituting the interpolation frame (4), the interpolation vector is regarded as the velocity vector V4 and coordinates corresponding to the position P4 If there is no interpolation vector, the velocity vector V4 is calculated by linear interpolation processing (intra-frame interpolation processing) or the like based on interpolation vectors of plural coordinates in the vicinity of the position P4.

  Then, by multiplying the velocity vector V4 by the frame interval Δt, the movement vector (the magnitude is Δt times the velocity vector V4 and in the same direction as the velocity vector V4) is calculated, and the position P5 moved by the movement vector from the position P4 ( Coordinates P5) are derived. The position P5 obtained by this becomes the position (coordinate of the movement destination) of the particle P in the vector frame (n + 1) which is the next frame (next time phase) of the interpolation frame (5).

  Thus, the particle operation unit 70 executes the same processing as above also in a plurality of frames (interpolated frame or vector frame) subsequent to the vector frame (n + 1) until one of the end conditions described later is satisfied. The destination of the particle P is derived. In addition, for each of the plurality of particles generated by the particle generation unit 60, the particle operation unit 70 derives a movement destination of the particles from the frame (time phase) in which each particle is generated.

  According to the specific example shown in FIG. 8, since the movement destination of each particle is derived based on the frame sequence after interpolation in which a plurality of interpolation frames are added between vector frames, the case where a plurality of interpolation frames are not added In comparison, the estimation accuracy of the moving destination is enhanced.

  For example, velocity vector V0 is multiplied by vector frame interval ΔT (see FIG. 6) from position P0 of particle P in vector frame (n) without using interpolation frames (1) to (4) in FIG. If the position moved by the obtained movement vector (size is ΔT times the velocity vector V0 and in the same direction as the velocity vector V0) is the movement destination of the particle P in the vector frame (n + 1), the example shown in FIG. A destination largely different from the position P5 (coordinate P5) is obtained. This is because changes in the velocity vector of the particle P between the vector frame (n) and the vector frame (n + 1) are not reflected unless the interpolation frames (1) to (4) are used.

  FIG. 9 is a diagram for explaining exception processing of operation of movement destination of each particle. The particle operation unit 70 derives the moving destination of each particle by the basic processing described using FIG. 8, but as shown in FIG. 9, when the moving destination of each particle exceeds the lumen line 52. The destination of each particle is corrected on the lumen line 52 or near the inner side (cardiac space side) of the lumen line 52.

  For example, as in the specific example shown in FIG. 9, the particle P is at the position P6 in each frame (vector frame or interpolation frame), and the movement destination in the next frame (vector frame or interpolation frame) obtained by basic processing is the position P7. If the movement vector (broken line arrow) intersects the lumen line 52, the movement destination in the next frame is corrected from the position P7 to the position P7 '. In the specific example of FIG. 9, the position P7 'is the intersection of the lumen line 52 and the movement vector, but for example, the vicinity (in the heart chamber side) of the lumen line 52 is the position P7' near the intersection. It may be done.

  FIG. 10 is a diagram for explaining an end condition of calculation of the movement destination of each particle. The particle operation unit 70 derives the moving destination of each particle one after another by the basic processing described using FIG. 8 and the exception processing described using FIG. 9, and as shown in FIG. 10, the movement of each particle When the tip passes through the outflow line 56, the calculation of the movement destination of the particle is ended.

  For example, as in the specific example shown in FIG. 10, when the particle P is at the position P8 in each frame (vector frame or interpolation frame) and the movement destination in the next frame (vector frame or interpolation frame) is the position P9, that is When the movement vector (broken line arrow) intersects the outflow line 56, the particle operation unit 70 corrects the movement destination in the next frame from the position P9 to the position P9 ', and ends the calculation of the movement destination of the particle P.

  In the specific example of FIG. 10, the position P9 'is the intersection of the outflow line 56 and the movement vector, but the vicinity of the intersection, for example, the upper side (cardiac cavity side) of the outflow line 56 is taken as the position P9'. May be

  When the particle generation unit 60 generates a plurality of particles, and the particle operation unit 70 sequentially calculates the movement destinations of the particles over a plurality of time phases (a plurality of frames) of each particle, the display image formation unit 80 A bloodstream display image is formed showing the particle destinations linked to one another. The display image forming unit 80 forms a blood flow display image in which the moving destinations of the plurality of particles are linked to each other by the wavefront line passing through the plurality of positions corresponding to the moving destinations of the plurality of particles.

  FIG. 11 is a diagram showing a specific example of a wavefront line. In FIG. 11, a plurality of particles (1) to (18) generated on the inflow line 54 connecting the start point S and the end point E by a straight line are illustrated. In FIG. 11, each black circle (filled circle) indicates the generation position of each particle. Although, for example, 50 particles are generated on the inflow line 54, only 18 particles are shown in FIG. 11 for convenience of illustration.

  The particle operation unit 70 sequentially calculates, for each particle, coordinate values of movement destinations of the particle over a plurality of time phases (plural frames) of the particle. The moving destinations of the plurality of particles (1) to (18) in one phase (one frame) are shown in FIG. In FIG. 11, each dashed circle indicates the destination of each particle.

  The display image forming unit 80 forms wavefront lines W passing through a plurality of positions corresponding to the destinations of the plurality of particles (1) to (18) for each time phase. For example, as in the specific example shown in FIG. 11, a wavefront line W is formed by connecting two particles adjacent to each other at the time of generation with a straight line and connecting a plurality of particles (1) to (18) with a broken line. The wavefront line W may be formed by a curve passing through the moving destinations of the plurality of particles (1) to (18) or an approximate curve passing through the vicinity of the moving destinations of the plurality of particles (1) to (18). Also, the wavefront line W may be formed based on some of all the tracked particles.

  Although the wavefront line W of only one of the multiple phases is shown in FIG. 11, the display image forming unit 80 displays multiple particles in that phase for each of the multiple phases. A wavefront line W passing through a plurality of positions corresponding to the movement destinations (1) to (18) is formed, and a blood flow display image showing the wavefront line W is formed.

  FIG. 12 is a view showing a specific example of a blood flow display image. The display image forming unit 80 forms the wave front line W for each time phase over a plurality of time phases, and for example, the blood showing the wave front line W on the ultrasound image of the heart obtained from the ultrasound image forming unit 20 Form a stream display image. In addition, a blood flow display image showing the wavefront line W may be formed on a color Doppler image formed by using the Doppler information obtained from the Doppler processing unit 30.

  In FIG. 12, wavefront phases W1 to W5 of multiple phases relating to multiple particles generated on the inflow line 54 are illustrated. For example, wavefront lines W are sequentially formed in the order of wavefront lines W1, W2, W3, W4, W5,... For each frame of a frame sequence after interpolation (see FIG. 5).

  A preferred example of the time phase interval in which the wavefront line W is formed is the frame interval of the frame sequence after interpolation (see FIG. 5), but the time phase interval in which the wavefront line W is formed is, for example, 20 mSec. It may be set to an arbitrary time such as (20 milliseconds), or may be adjustable to a desired length by the user, for example.

  Furthermore, the number (five in the specific example of FIG. 12) of wavefront lines W to be displayed at one time (in the same display frame) in the blood flow display image or the selection condition of wavefront lines W to be displayed at one time As to which time phase is to be displayed, etc.), for example, it is desirable to be appropriately adjusted in accordance with the diagnostic content, the preference of the user, and the like.

  A user such as a doctor or a laboratory technician can visually and intuitively grasp, for example, which part of a plurality of particles has reached which part of the heart from a blood flow display image Become. Therefore, the blood flow display image is expected to be used for detection and diagnosis of various diseases related to the heart.

  FIG. 13 is a view showing blood flow display images of a healthy example and a disease example. The healthy example shown in FIG. 13 <A> is a specific example of a blood flow display image in the left ventricle of a healthy heart, and an inflow line 54 is set on the mitral valve or in the vicinity of the mitral valve in the image. . In the healthy example of FIG. 13 <A>, the wavefront line W of the plurality of particles generated on the inflow line 54 is formed so as to extend entirely in the left ventricle (within the lumen line 52). That is, the blood flowed into the left chamber through the mitral valve spreads throughout the left chamber.

  On the other hand, the disease example shown in FIG. 13 <B> is a specific example of a blood flow display image in the left ventricle of a heart whose movement of the heart wall is not healthy due to, for example, a myocardial infarction. In the example of the disease of FIG. 13 <B>, the wavefront line W of the plurality of particles generated on the inflow line 54 is biased to the left side of the figure. That is, it can be seen that the blood flowed into the left chamber through the mitral valve does not extend to the entire left chamber.

  Moreover, the example of a disease shown to FIG. 13 <C> is a specific example of the blood-flow display image in the left ventricle of the heart in which the aneurysm was made. In the example of the disease of FIG. 13 <C>, it can be seen that the blood does not flow to the area of the mass or the blood flow is insufficient.

  Thus, it is expected that the condition of the heart can be diagnosed visually from the blood flow display image. Needless to say, in the actual diagnosis, cases and the like should be determined by the diagnosis of a specialist such as a doctor.

  In addition, the display image forming unit 80 forms, for each particle of the plurality of particles, a particle distance graph indicating the distance from the generation position of the particles to the movement destination.

  FIG. 14 is a diagram showing a specific example of a particle distance graph. The display image forming unit 80 forms a particle distance graph in which the generation position of each particle is shown on the horizontal axis and the distance of each particle is shown on the vertical axis, as in the example shown in FIG. 14, for example.

  If a plurality of particles are generated on the inflow line 54 (see FIGS. 7 and 11), the horizontal axis of the particle distance graph shown in FIG. 14 corresponds to the inflow line 54.

  The distance on the vertical axis is the distance from the position where each particle is generated (for example, on the inflow line 54) to the movement destination of that particle, for example, the linear distance from the generation position of each particle to the movement destination is preferred Although there is a certain distance, the movement distance (the distance along the traced path) from the generation position of each particle to the movement destination may be used. In the example shown in FIG. 14, the distance of each particle is shown by the length of the broken straight line.

  The display image forming unit 80 forms a particle distance graph showing distances of a plurality of particles for each time phase over a plurality of time phases. For example, as in the specific example shown in FIG. 14, the distances of a plurality of particles are shown for each time phase in the order of time phases 1, 2, 3, 4, 5, 6,. In the specific example of FIG. 14, the positions of black circles (filled circles) which can be indicated for each time phase indicate the distance of each particle.

  The particle distance graph of FIG. 14 shows the maximum distance of each particle with respect to multiple particles. The maximum value of the distance of each particle is maintained (peak hold) in the particle distance graph, and a maximum distance line is formed by connecting the maximum distances of the plurality of particles by a line or a curve.

  Furthermore, the display image forming unit 80 subjects the blood flow display image (FIGS. 12 and 13) and the particle distance graph (FIG. 14) to a coloring process according to the position at which each particle is generated.

  FIG. 15 is a diagram for describing a specific example of the coloring process according to the generation position. FIG. 15 shows a specific example of a color palette used for coloring processing on a blood flow display image and a particle distance graph.

  In the color palette of FIG. 15, the color at each position is associated with the position at which each particle is generated as the horizontal axis. If a plurality of particles are generated on the inflow line 54 (see FIGS. 7 and 11), the horizontal axis of the color pallet shown in FIG. 15 corresponds to the inflow line 54. That is, in the color palette, colors corresponding to the respective positions on the inflow line 54 from the start point S to the end point E are shown.

  The RGB curve (1) is a specific example of the color arrangement pattern in the color palette. The horizontal axis of the RGB curve (1) is the same as that of the color palette, and corresponds to each position on the inflow line 54 from the start point S to the end point E. The vertical axis of the RGB curve (1) indicates the luminance value of each primary color of red (R), green (G) and blue (B).

  In the RGB curve (1), at the position of the start point S, the luminance value of blue is set to the maximum value (for example, 255), and the luminance values of green and red are set to the minimum value (for example, 0). Also, from the position of the starting point S to the middle position M, the green brightness value is increased while decreasing the blue brightness value, and the green brightness value is made maximum at the middle position M, and the blue and red brightness values are minimum. It is considered a value. Furthermore, from the intermediate position M to the position of the end point E, the red luminance value is increased while decreasing the green luminance value, and at the position of the end point E, the red luminance value is made the maximum value, and blue and green luminance values Is the minimum value.

  Further, as shown in the RGB curve (2), the luminance values of the respective primary colors of red (R), green (G) and blue (B) may be generally increased by adding an offset. The magnitude of the offset is, for example, about 1/3 of the difference between the maximum value and the minimum value of the luminance values. Of course, the magnitude of the offset may be adjustable by the user, for example.

  The display image forming unit 80 subjects the blood flow display image (FIGS. 12 and 13) and the particle distance graph (FIG. 14) to a coloring process, for example, in accordance with the color palette of FIG.

  In the wavefront line W corresponding to each time phase in the blood flow display image, the display image forming unit 80 expresses the line portion corresponding to the movement destination of each particle in a color according to the position at which each particle is generated. Do. For example, in the wavefront line W shown in FIG. 11, the line portion in the vicinity of the movement destination (broken line circle) of the particle (1) is expressed by a color corresponding to the position (filled circle) at which the particle (1) is generated. . The color corresponding to the position where the particle (1) is generated is selected, for example, from the color palette of FIG. Similarly, the color corresponding to the position (solid circle) at which the particle (broken line circle) in that portion is assigned to the other line portion in the wavefront line W shown in FIG.

  Further, the display image forming unit 80 forms a particle distance graph in which the distance of each particle is expressed in a color corresponding to the position at which each particle is generated. For example, in the particle distance graph shown in FIG. 14, a broken line indicating the distance of each particle is represented by a color corresponding to the position at which the particle is generated. The color corresponding to the position where each particle was generated is selected from, for example, the color palette of FIG. In addition, it is desirable to perform coloring processing corresponding to the position where each particle was generated also on the maximum distance line shown in the particle distance graph.

  Then, by using a common color palette (for example, the color palette in FIG. 15) for the blood flow display image and the particle distance graph, the correspondence between each particle in the blood flow display image and each particle in the particle distance graph It becomes easy for the relationship to be understood visually.

  The display image forming unit 80 may form a display image in which the blood flow display image and the particle distance graph are arranged, or may form a display image in which the blood flow display image and the particle distance graph are individually shown.

  While the preferred embodiments of the present invention have been described above, the above-described embodiments are merely illustrative in every respect, and do not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof.

  Reference Signs List 10 probe 12 transmitting / receiving unit 20 ultrasound image forming unit 30 Doppler processing unit 40 velocity vector computing unit 42 lumen line setting unit 44 inflow / outflow line setting unit 46 lumen line velocity calculating unit 50 interpolation processing Part, 60 particle generation part, 70 particle operation part, 80 display image forming part, 100 control part.

Claims (6)

A vector operation unit for obtaining a blood flow vector of blood flow in a heart chamber of a heart based on a signal obtained by transmitting and receiving ultrasonic waves;
A particle generation unit for generating virtual multiple particles of blood flow in the heart chamber;
A particle operation unit for deriving a movement destination of each particle based on the blood flow vector;
An image forming unit for forming a blood flow image in which moving destinations of the plurality of particles are shown in connection with each other;
I have a,
The image forming unit forms a graph indicating the distance from the generation position of the particles to the movement destination for each particle of the plurality of particles.
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 1,
The image forming unit forms a blood flow image in which the moving destinations of the plurality of particles are linked to each other by showing the line passing through the plurality of positions corresponding to the moving destinations of the plurality of particles.
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 2,
The image forming unit forms the blood flow image in which a line portion corresponding to the moving destination of each particle on the line is expressed in a color corresponding to the position at which each particle is generated.
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 2 or 3,
The image forming unit forms the line passing through a plurality of positions corresponding to destinations of the plurality of particles in the time phase for each time phase over a plurality of time phases.
An ultrasonic diagnostic apparatus characterized by The ultrasonic diagnostic apparatus according to any one of claims 1 to 4 .
The image forming unit forms the graph in which the generation position of each particle is indicated on one axis and the distance of each particle is indicated on the other axis.
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 5 ,
The image forming unit forms the graph in which the distance of each particle is expressed in a color according to the position where each particle is generated.
An ultrasonic diagnostic apparatus characterized by