JP2016214550A - Ultrasound diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device that is capable of providing a new display mode expressing a state of bloodstream in heart.SOLUTION: A speed vector calculation part 40 obtains a speed vector of bloodstream in a heart cavity on the basis of a signal obtained by transmitting and receiving an ultrasonic wave. A particle generation part 60 generates multiple virtual particles of the bloodstream in the heart cavity. A particle calculation part 70 derives destinations of the respective particles on the basis of the speed vector of the bloodstream. A display image forming part 80 forms a bloodstream display image that shows the destinations of the particles in association with one another. The display image forming part 80 forms a wavefront line passing through multiple positions corresponding to the destinations of the particles and then shows the destinations of the particles that are mutually associated by the wavefront line.SELECTED DRAWING: Figure 1

Description

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

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

  Patent Document 2 discloses an ultrasonic diagnostic apparatus that forms an image representing blood flow in a living body as movements of a plurality of display elements. As each display element, a virtual particle of blood flow is suitable, and the apparatus described in Patent Document 2 is based on the velocity vector of each particle in the current frame and the position (movement destination) of the particle in the next frame. ), And for example, the trajectory of each particle obtained by tracking the movement destination of each particle over a plurality of frames is displayed. Thereby, for example, states such as vortex, turbulence, and stagnation in the bloodstream can be visually and intuitively confirmed.

JP 2013-192643 A JP 2008-73279 A

  The techniques described in Patent Documents 1 and 2 are epoch-making techniques with extremely high utility value in obtaining blood flow movement information (motion information), and further application and improvement of these techniques. Is expected. In particular, application to diagnosis of blood flow in the heart is expected.

  By the way, the heart in the living body repeats the expansion and contraction motion, and the blood flow in the heart changes in a complicated manner by the expansion and contraction motion. Therefore, conventionally, attempts have been made to appropriately and easily express the state of blood flow that changes in a complex manner.

  The present invention has been made in view of the background art described above, and an object of the present invention 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 object includes a vector calculation unit that obtains a blood flow vector of blood flow in the heart chamber of the heart based on a signal obtained by transmitting and receiving ultrasound, and blood in the heart chamber. A particle generation unit that generates a plurality of virtual particles of a flow, a particle calculation 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 connected to each other And an image forming unit that forms an image.

  In the above configuration, the blood flow vector is vector information related to the blood flow motion. For example, the 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. A preferred example is a movement vector indicating the amount and direction of movement. The blood flow vector can be obtained using, for example, the technique described in Patent Document 1 (Japanese Patent Laid-Open No. 2013-192643), that is, using a two-dimensional velocity vector distribution, but other known techniques are used. Thus, a blood flow vector may be obtained.

  In addition, each virtual particle of blood flow is a virtual element in computation used for analyzing blood flow (blood flow). 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 movement destinations of a plurality of particles are linked to each other. For example, a blood flow image is formed by a display mode in which the movement destinations of a plurality of particles are closely associated with each other. Specifically, although a blood flow image in which the movement destinations of the plurality of particles are connected to each other by a line passing through a plurality of positions corresponding to the movement destination of the plurality of particles is preferable, the plurality of particles are displayed in a display mode other than the line. May be linked to each other.

  And according to the apparatus provided with the said structure, the blood-flow image of the new display mode which connected and showed the movement destination of multiple particles mutually is provided. With this blood flow image, users such as doctors and laboratory technicians can visually and intuitively know which part of a plurality of particles reaches which part of the heart, for example. Become.

  In a desirable specific example, the image forming unit shows the blood flow image showing a line passing through a plurality of positions corresponding to the movement destination of the plurality of particles, and connecting the movement destination of the plurality of particles to each other by the line. Is formed.

  In a desirable specific example, the image forming unit forms the blood flow image expressing a line portion corresponding to a movement destination of each particle on the line with a color according to a position where the particle is generated. It is characterized by that.

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

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

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

  In a desirable specific example, the image forming unit forms the graph in which the distance between the particles is expressed in a color corresponding to the position where the particles are 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 aspect of the present invention, a blood flow image in a new display mode in which the movement destinations of a plurality of particles are connected to each other is provided, whereby a user such as a doctor or a laboratory technician can It is possible to visually and intuitively understand which of the particles reach which part of the heart.

1 is a diagram illustrating an overall configuration of an ultrasonic diagnostic apparatus that is preferable in the practice of the present invention. It is a figure which shows the specific example of the region of interest corresponding to the heart 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 velocity vector distribution. It is a figure for demonstrating a frame row | line. It is a figure for demonstrating the interpolation process between frames. It is a figure for demonstrating the production | generation of multiple particles. 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 the exception process of the calculation of the movement destination of each particle | grain. It is a figure for demonstrating the completion | finish conditions of the calculation of the movement destination of each particle | grain. It is a figure which shows the specific example of a wavefront 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 distance graph. It is a figure for demonstrating the specific example of the coloring process according to a production | generation position.

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

  The probe 10 is an ultrasonic probe that transmits and receives an ultrasonic wave to a region including a diagnosis target such as a heart in a living body. The probe 10 includes a plurality of vibration elements, and 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) such as a doctor and contacting the body surface of the subject. The probe 10 may be used by being inserted into a body cavity of a subject, or may be a probe that combines electronic scanning and mechanical scanning. The probe 10 may be, for example, a sector type or a linear type although a convex type is desirable.

  The transmission / reception unit 12 has functions as a transmission beam former and a reception beam former. That is, the transmission / reception unit 12 forms a transmission beam by outputting a transmission signal to each of the plurality of vibration elements included in the probe 10, and further receives a plurality of reception signals obtained from the plurality of vibration elements. A reception beam is formed by performing phasing addition processing or the like. Thereby, the ultrasonic beam (transmission beam and reception beam) is scanned in the scanning plane, and a reception signal corresponding to the ultrasonic beam is formed.

  In the transmission / reception unit 12, detection processing, filtering processing, AD conversion processing, or the like may be performed on the ultrasonic reception signal. Further, in obtaining an ultrasonic reception signal, the ultrasonic beam may be scanned three-dimensionally in the tertiary space, or a technique such as transmission aperture synthesis may be used.

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

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

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

  Various known techniques can be used to form a two-dimensional velocity vector distribution in the scanning plane using one-dimensional velocity information along the ultrasonic beam direction. Of course, two ultrasonic beams having different directions may be formed, velocity information may be obtained from each of the two ultrasonic beams, and a two-dimensional velocity vector may be formed.

  The velocity vector calculation unit 40 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 the xy plane corresponding to the ultrasonic scanning plane to form a two-dimensional velocity vector distribution. Note that a two-dimensional velocity vector distribution may be formed in a scanning coordinate system corresponding to ultrasonic scanning, for example, an rθ coordinate system based on the beam depth direction r and the beam scanning direction θ.

  The velocity vector calculation unit 40 generates each vector frame indicating a two-dimensional velocity vector distribution composed of velocity vectors corresponding to a plurality of sample points (a plurality of coordinates). Further, 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 serving as the outer edge of the heart lumen in the image data obtained by the processing by the ultrasonic image forming unit 20. The inflow / outflow line setting unit 44 sets an inflow line in the flow path of blood flowing into the heart lumen in the image data, and sets an outflow line in the flow path of blood flowing out of the heart lumen. A region surrounded by the lumen line, the inflow line, and the outflow line is set as a region of interest.

  FIG. 2 is a diagram illustrating a specific example of a region of interest corresponding to a heart lumen. FIG. 2 shows a specific example of the image data 22 obtained in the ultrasonic image forming unit 20. The image data 22 in FIG. 2 includes a lumen of the left ventricle of the heart surrounded by a heart muscle and a valve. (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 (for example, the lumen of the left ventricle of the heart). 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 to display some images on or near the boundary between the heart chamber and the myocardium. Set the 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) including a plurality of trace reference points and a plurality of added trace points. For example, the lumen line 52 is formed to connect a plurality of sample points to each other. The boundary between the heart cavity and the myocardium may be specified 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 in accordance with an operation from the user. For example, a user such as a doctor designates the positions of the start point S and the end point E of the inflow line 54 and the outflow line 56 while viewing the display image corresponding to the image data 22. For example, these four points are set in the order of the start point S and end point E of the inflow line 54 and the start point S and end point E of the outflow line 56.

  When the user sets the positions of the start point S and the end point E of the inflow line 54 and the outflow line 56, the inflow / outflow line setting unit 44 sets the inflow line 54 to connect the lumen line 52 and the inflow line 54. The outflow line 56 is set so that the lumen line 52 and the outflow line 56 are connected.

  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.

  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. It is desirable that 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, a region surrounded by the lumen line 52, the inflow line 54, and the outflow line 56 is formed, and the region is set as a region of interest. In addition, although the specific example which made the inflow line 54 and the outflow line 56 into a straight line was shown in FIG. 2, lines other than a straight line may be utilized.

  FIG. 3 is a diagram illustrating another specific example of the inflow line 54 and the outflow line 56. For example, when a closed curved lumen line 52 is obtained as in the specific example shown in FIG. 3A, the start point S and the end point E are set to the lumen line 52 as shown in FIG. A curved inflow line 54 and an outflow line 56 connected along the line may be formed.

  Returning to FIG. 1, the lumen line speed calculator 46 calculates velocity information of the myocardium (heart wall) on the lumen line (reference numeral 52 in FIG. 2) based on the image data formed in the ultrasonic image forming unit 20. Is generated. The lumen line velocity calculation unit 46 generates myocardial velocity information for each sample point for a plurality of sample points on the lumen line.

  The lumen line speed calculation unit 46 performs pattern matching using, for example, correlation calculation based on pixel values (luminance values, etc.) of image data between frames of image data of ultrasonic 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. For example, a two-dimensional velocity vector is calculated based on the movement amount (movement vector) between frames and the time between frames. If the image data is data corresponding to the xy orthogonal coordinate system, the velocity vector in the xy orthogonal coordinate system is calculated, and if the image data is data corresponding to the rθ coordinate system, the velocity vector in the rθ coordinate system is calculated. .

  The tracking result of each sample point on the lumen line by the lumen line speed calculation unit 46 is sent to the lumen line setting unit 42 so that the lumen line setting unit 42 follows the movement of a plurality of sample points. The shape of the lumen line is changed.

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

  In the velocity vector calculation unit 40, when obtaining a two-dimensional velocity vector of blood flow by the method described in Patent Document 1, the motion information of the heart wall is used. In this case, the 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 calculation unit 44 is used.

  The processing and functions in the interpolation processing unit 50, the particle generation unit 60, and the particle calculation 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 ultrasound image obtained from the ultrasound image forming unit 20 and the computation result obtained from the particle computation unit 70. The blood flow display image formed in is displayed on the display unit 82.

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

  Among the configurations shown in FIG. 1 (respectively assigned parts), the transmission / reception unit 12, the ultrasonic image forming unit 20, the Doppler processing unit 30, the velocity vector calculation unit 40, the lumen line setting unit 42, the inflow / outflow line setting unit 44, the lumen line velocity calculation unit 46, the interpolation processing unit 50, the particle generation unit 60, the particle calculation unit 70, and the display image forming unit 80 are realized by using hardware such as an electric / electronic circuit or a processor. In the implementation, a device such as a memory may be used as necessary. In addition, at least some 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 between hardware such as a CPU, a processor, and a memory and software (program) that defines the operation of the CPU and the processor.

  A preferred specific example of the display unit 82 is a liquid crystal display or the like, and the operation device 90 can be realized by at least one of a mouse, a keyboard, a trackball, a touch panel, and other switches, for example. And the control part 100 is realizable by cooperation with hardwares, such as CPU, a processor, a memory, and the software (program) which prescribes | regulates operation | movement of CPU, a processor, for example.

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

  FIG. 4 is a diagram illustrating a specific example of the velocity vector distribution. For example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2013-192643), the velocity vector calculation unit 40 performs scanning using velocity information in the ultrasonic beam direction about blood flow and motion information of the heart wall. A two-dimensional velocity vector of blood flow at each position in the plane is obtained. 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 calculation unit 46. For example, the velocity vector distribution shown in FIG. 4 is formed.

  The velocity vector distribution shown in FIG. 4 is expressed in an xy coordinate system (orthogonal coordinate system) including the lumen line 52 (see FIG. 2) of the heart, and a plurality of velocities calculated at a plurality of coordinates in the xy coordinate system. It consists of a vector (blood flow velocity vector) V. For example, the velocity vector calculation unit 40 forms a two-dimensional velocity vector distribution in a scanning coordinate system corresponding to ultrasonic scanning, for example, an rθ coordinate system based on the beam depth direction r and the beam scanning direction θ, A coordinate conversion process is performed to obtain a velocity vector distribution in the xy coordinate system shown in FIG.

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

  FIG. 5 is a diagram for explaining the frame sequence. FIG. 5A shows a specific example of the 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 in a plurality of coordinates is generated using velocity information (Doppler information) in the ultrasonic beam direction obtained from the Doppler processing unit 30. In obtaining Doppler information, for example, when transmission / reception of the color Doppler method is used, ultrasonic waves are repeatedly transmitted and received in the same beam direction. For example, compared to obtaining a B-mode image, the transmission / reception frame rate for obtaining Doppler information Will be lower. Since the velocity vector constituting each vector frame is calculated using Doppler information, the frame rate of the vector frame sequence is relatively low.

  Therefore, the interpolation processing unit 50 performs inter-frame interpolation processing on the vector frame sequence. FIG. 5B shows a specific example of the post-interpolation frame sequence subjected to the inter-frame interpolation processing. In the specific example shown in FIG. 5B, the corrected frame sequence is added between a plurality of vector frames (1 to 5 typically shown in FIG. 5A) and those vector frames. Consists of multiple interpolation frames. Each interpolation frame is generated by applying an interpolation process based on a velocity vector between two adjacent vector frames.

  The frame rate of the interpolated frame sequence may be determined according to the display frame rate in the display unit 82, for example. 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 interpolated frame sequence is also 60 Hz. Of course, the display frame rate and the frame rate of the interpolated frame sequence need not necessarily match.

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

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

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

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

[Equation 1]
Interpolation vector at coordinate (x, y) of interpolation frame (1) x-direction component = {(Vx0 · 4Δt) + (Vx1 · Δt)} / 5Δt
y-direction component = {(Vy0 · 4Δt) + (Vy1 · Δt)} / 5Δt
[Equation 2]
Interpolation vector at coordinates (x, y) of interpolation frame (2) x-direction component = {(Vx0 · 3Δt) + (Vx1 · 2Δt)} / 5Δt
y-direction component = {(Vy0 · 3Δt) + (Vy1 · 2Δt)} / 5Δt
[Equation 3]
Interpolation vector at coordinates (x, y) of interpolation frame (3) x-direction component = {(Vx0 · 2Δt) + (Vx1 · 3Δt)} / 5Δt
y-direction component = {(Vy0 · 2Δt) + (Vy1 · 3Δt)} / 5Δt
[Equation 4]
Interpolation vector at coordinates (x, y) of 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 specific examples in the case of using linear interpolation according to the time interval, and linear interpolation may be realized using other equations, or linear interpolation. The interpolation vector may be calculated using an interpolation process other than the above. Furthermore, when calculating the interpolation vector at each coordinate, for example, a velocity vector near the coordinate other than the coordinate may be referred to. Further, for example, in the interpolation process between the vector frame (n) and the vector frame (n + 1), a velocity vector other than these two vector frames, for example, in a vector frame in the vicinity of these two vector frames is used. Good.

  The interpolation processing unit 50 performs inter-frame interpolation processing for each coordinate with respect to the plurality of coordinates from which the velocity vector distribution is obtained, thereby obtaining an interpolation vector, thereby forming each interpolation frame composed of interpolation vectors at the plurality of coordinates. To 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 interpolated frame sequence, a virtual multiple particle movement destination relating to blood flow is calculated. The virtual plural particles are generated by the particle generation unit 60.

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

  For example, as in the basic example shown in FIG. 7, a plurality of particles arranged in an example at regular intervals are generated on the inflow line 54 in which the start point S and the end point E are connected by a straight line. For example, 50 particles are generated on the inflow line 54 at equal intervals. In addition, when the length of the inflow line 54 is 50 pixels (pixels) or less, one particle is generated for each 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 be allowed to set or change the number of particles.

  The particle generator 60 desirably generates a plurality of particles in only one specific frame (only in one time phase). For example, the particle generation unit 60 generates a plurality of particles in the first frame that is the starting point of the calculation. The particle generator 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 so as not to impair the visibility of a blood flow display image described later.

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

  FIG. 8 is a diagram for explaining a specific example of the calculation of the movement destination of each particle. 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 calculation related to 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 the blood flow at the position P0. V0 is used. If a velocity vector having coordinates corresponding to the position P0 (coordinate P0) is present in the velocity vectors having a plurality of 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 (intraframe interpolation processing) based on the velocity vectors of a plurality of coordinates near 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 obtained in this way becomes the position (coordinate of the movement destination) of the particle P in the interpolation frame (1) which is the next frame (next time phase) of the vector frame (n).

  Next, the blood flow velocity vector V1 at the position P1 is used. If an interpolated vector corresponding to the position P1 (coordinate P1) exists in the interpolated vector constituting the interpolated frame (1), the interpolated vector is set as the velocity vector V1, and the coordinate corresponding to the position P1 If there is no interpolation vector, the velocity vector V1 is calculated by linear interpolation processing (intraframe interpolation processing) based on an interpolation vector of a plurality of coordinates in the vicinity of 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 a position P2 (only the movement vector is moved from the position P1) Coordinate P2) is derived. The position P2 obtained in this way 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 processing as described above is executed for 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, a blood flow velocity vector V4 at the position P4 is used. If there is an interpolation vector corresponding to the position P4 (coordinate P4) among the interpolation vectors of a plurality of coordinates constituting the interpolation frame (4), the interpolation vector is set as the velocity vector V4, and the coordinates corresponding to the position P4 If there is no interpolation vector, the velocity vector V4 is calculated by linear interpolation processing (intraframe interpolation processing) based on interpolation vectors of a plurality of coordinates near the position P4.

  Then, by multiplying the velocity vector V4 and the frame interval Δt, a movement vector (the magnitude is Δt times the velocity vector V4 and the same direction as the velocity vector V4) is calculated, and a position P5 (moved by the movement vector from the position P4) ( Coordinate P5) is derived. The position P5 obtained as a result 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).

  In this way, the particle calculation unit 70 performs the same processing as described above for a plurality of frames (interpolation frame or vector frame) subsequent to the vector frame (n + 1), and successively until an end condition described later is satisfied. The movement destination of the particle P is derived. Moreover, the particle | grain calculating part 70 derives | leads out the movement destination of the particle | grain from the flame | frame (time phase) in which each particle | grain was produced | generated about each of the several particle | grains which the particle | grain production | generation part 60 produced | generated.

  According to the specific example shown in FIG. 8, since the movement destination of each particle is derived based on the interpolated frame sequence in which a plurality of interpolation frames are added between vector frames, when a plurality of interpolation frames are not added. In comparison, the estimation accuracy of the destination can be improved.

  For example, without using the interpolation frames (1) to (4) in FIG. 8, the velocity vector V0 is multiplied by the vector frame interval ΔT (see FIG. 6) from the position P0 of the particle P in the vector frame (n). If the position moved by the obtained movement vector (the magnitude of which is ΔT times the velocity vector V0 and the same direction as the velocity vector V0) is set as the movement destination of the particle P in the vector frame (n + 1), it can be obtained in the specific example of FIG. A moving destination greatly different from the position P5 (coordinate P5) is obtained. This is because the change in the velocity vector of the particle P between the vector frame (n) and the vector frame (n + 1) is not reflected unless the interpolation frames (1) to (4) are used.

  FIG. 9 is a diagram for explaining exception processing of the calculation of the movement destination of each particle. The particle calculation unit 70 derives the movement destination of each particle by the basic processing described with reference to FIG. 8, but when the movement destination of each particle exceeds the lumen line 52 as shown in FIG. 9. Corrects the movement destination of each particle on the lumen line 52 or near the inner side (cardiac cavity 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 the basic processing is the position P7. In other words, that is, when the movement vector (broken arrow) and the lumen line 52 intersect, 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, and for example, the vicinity of the inner side of the lumen line 52 (the heart chamber side) is the position P7 ′. May be.

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

  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) and the outflow line 56 intersect, the particle calculation 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 vicinity of the upper side (heart chamber side) of the outflow line 56 is the position P9 ′. May be.

  When the particle generation unit 60 generates a plurality of particles, and the particle calculation unit 70 calculates the movement destination for each particle over a plurality of time phases (a plurality of frames) one after another, the display image forming unit 80 includes a plurality of display image forming units 80. A blood flow display image showing the movement destinations of the particles connected to each other is formed. The display image forming unit 80 forms a blood flow display image in which the movement destinations of the plurality of particles are connected to each other by wavefront lines passing through the plurality of positions corresponding to the movement destinations of the plurality of particles.

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

  The particle calculation unit 70 sequentially calculates the coordinate values of the movement destination for each particle over a plurality of time phases (a plurality of frames). FIG. 11 illustrates the movement destinations of the plurality of particles (1) to (18) in one time phase (one frame). In FIG. 11, each broken line circle indicates the movement destination of each particle.

  The display image forming unit 80 forms wavefront lines W passing through a plurality of positions corresponding to the movement 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 in which two particles adjacent at the time of generation are connected by a straight line and a plurality of particles (1) to (18) are connected by a broken line. The wavefront line W may be formed by a curve passing through the destinations of the plurality of particles (1) to (18), an approximate curve passing through the vicinity of the destinations of the plurality of particles (1) to (18), and the like. Further, the wavefront line W may be formed based on some of all the tracked particles.

  FIG. 11 illustrates a wavefront line W for only one time phase among a plurality of time phases, but the display image forming unit 80 has a plurality of particles in each time phase over a plurality of time phases. Wavefront lines W passing through a plurality of positions corresponding to the movement destinations (1) to (18) are formed, and a blood flow display image showing the wavefront lines W is formed.

  FIG. 12 is a diagram illustrating a specific example of a blood flow display image. The display image forming unit 80 forms a wavefront line W for each time phase over a plurality of time phases. For example, the blood showing the wavefront line W on the ultrasound image of the heart obtained from the ultrasound image forming unit 20 A stream display image is formed. Further, a blood flow display image showing the wavefront line W may be formed on a color Doppler image formed using Doppler information obtained from the Doppler processing unit 30.

  In FIG. 12, wavefront lines W1 to W5 having a plurality of time phases related to a plurality of particles generated on the inflow line 54 are illustrated. For example, wavefront lines W are successively formed in the order of wavefront lines W1, W2, W3, W4, W5,... For each frame of the interpolated frame sequence (see FIG. 5).

  A preferred specific example of the time phase interval at which the wavefront line W is formed is the frame interval of the interpolated frame sequence (see FIG. 5), but the time phase interval at 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 adjusted to a desired length by the user, for example.

  Further, the number of wavefront lines W to be displayed at one time (in the same display frame) in the blood flow display image (5 in the specific example of FIG. 12) and the selection conditions (from which time phase) of the wavefront lines W to be displayed at a time It is desirable that the time phase to be displayed is appropriately adjusted according to, for example, the diagnosis contents and user preferences.

  Users such as doctors and laboratory technicians can visually and intuitively grasp, for example, which part of a plurality of particles has reached which part of the heart from the blood flow display image. Become. Therefore, the blood flow display image is expected to be used for discovery and diagnosis of various diseases related to the heart.

  FIG. 13 is a diagram 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 or near the mitral valve in the image. . In the healthy example of FIG. 13 <A>, the wavefront lines W of a plurality of particles generated on the inflow line 54 are formed so as to spread as a whole in the left chamber (inside the lumen line 52). That is, the blood flow that flows into the left ventricle through the mitral valve spreads widely throughout the left ventricle.

  In contrast, the disease example shown in FIG. 13 <B> is a specific example of a blood flow display image in the left ventricle of the heart whose heart wall motion is not healthy due to, for example, myocardial infarction. In the disease example of FIG. 13 <B>, the wavefront line W of a 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 flow that flows into the left ventricle through the mitral valve does not reach the entire left ventricle.

  Moreover, the disease example shown in FIG. 13 <C> is a specific example of the blood flow display image in the left chamber of the heart where the aneurysm is formed. In the disease example of FIG. 13 <C>, it can be seen that blood does not flow in the region of the aneurysm or blood flow is insufficient.

  Thus, it is expected that the state of the heart can be visually diagnosed from the blood flow display image. In actual diagnosis, it goes without saying that cases and the like should be determined by the diagnosis of an expert such as a doctor.

  The display image forming unit 80 forms a particle distance graph showing the distance from the generation position of the particle to the destination for each particle of the plurality of particles.

  FIG. 14 is a diagram illustrating a specific example of a particle distance graph. For example, 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 specific example shown in FIG.

  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.

  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 the particle. For example, a linear distance from the generation position of each particle to the movement destination is preferable. Although there is a movement distance (a distance along the tracked path) from the generation position of each particle to the movement destination, it may be used. In the specific example shown in FIG. 14, the distance of each particle is indicated by the length of a broken line.

  The display image forming unit 80 forms a particle distance graph indicating the distance of a plurality of particles for each time phase over a plurality of time phases. For example, like the specific example shown in FIG. 14, the distance of a plurality of particles is 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 position of a black circle (filled circle) that can be shown for each time phase indicates the distance of each particle.

  The particle distance graph of FIG. 14 shows the maximum distance of each particle regarding a plurality of particles. The maximum value of the distance of each particle is maintained (peak hold) in the particle distance graph, and a maximum distance line in which the maximum distances of a plurality of particles are connected by a broken line or a curve is formed.

  Further, the display image forming unit 80 performs a coloring process according to the position where each particle is generated on the blood flow display image (FIGS. 12 and 13) and the particle distance graph (FIG. 14).

  FIG. 15 is a diagram for explaining 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 for 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 where 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. That is, colors corresponding to the respective positions on the inflow line 54 from the start point S to the end point E are shown in the color palette.

  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 values of the primary colors of red (R), green (G), and blue (B).

  In the RGB curve (1), at the position of the start point S, the blue luminance value is the maximum value (for example, 255), and the green and red luminance values are the minimum value (for example, 0). Further, from the position of the starting point S to the intermediate position M, the green luminance value is increased while lowering the blue luminance value, and the green luminance value is maximized at the intermediate position M, and the blue and red luminance values are minimum. Value. Further, from the intermediate position M to the end point E, the red brightness value is increased while decreasing the green brightness value. At the end point E position, the red brightness value is maximized, and the blue and green brightness values are increased. Is the minimum value.

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

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

  The display image forming unit 80 expresses the line portion corresponding to the movement destination of each particle in a color corresponding to the position where each particle is generated in the wavefront line W corresponding to each time phase in the blood flow display image. To do. For example, in the wavefront line W shown in FIG. 11, the line portion in the vicinity of the movement destination (dashed circle) of the particle (1) is expressed by a color corresponding to the position (filled circle) where the particle (1) is generated. . The color corresponding to the position where the particle (1) is generated is selected from, for example, the color palette shown in FIG. Similarly, for other line portions in the wavefront line W shown in FIG. 11, colors corresponding to positions (filled circles) where particles (broken circles) are generated in those portions are assigned.

  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 where 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 expressed by a color corresponding to the position where the particle is generated. For example, the color corresponding to the position where each particle is generated is selected from the color palette shown in FIG. In addition, it is desirable to perform the coloring process 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 to grasp the relationship 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 individually showing the blood flow display image and the particle distance graph.

  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, 12 Transmission / reception part, 20 Ultrasound image formation part, 30 Doppler processing part, 40 Velocity vector calculation part, 42 Lumen line setting part, 44 Inflow / outflow line setting part, 46 Lumen line speed calculation part, 50 Interpolation process Unit, 60 particle generation unit, 70 particle calculation unit, 80 display image forming unit, 100 control unit.

Claims (7)

A vector calculation unit for obtaining a blood flow vector of blood flow in the heart chamber of the heart based on a signal obtained by transmitting and receiving ultrasonic waves;
A particle generation unit that generates a plurality of virtual particles of blood flow in the heart chamber;
A particle calculation 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 showing the movement destinations of the plurality of particles connected to each other;
Having
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The image forming unit forms the blood flow image indicating the movement destinations of the plurality of particles connected to each other by the lines by indicating lines passing through a plurality of positions corresponding to the movement destinations of the plurality of particles.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 2,
The image forming unit forms the blood flow image expressing a line portion corresponding to a movement destination of each particle on the line with a color according to a position where the particle is generated.
An ultrasonic diagnostic apparatus. 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 the movement destinations of the plurality of particles in the time phase for each time phase over a plurality of time phases.
An ultrasonic diagnostic apparatus. In the ultrasonic diagnostic apparatus according to any one of claims 1 to 4,
The image forming unit forms a graph showing a distance from a generation position of the particle to a destination for each particle of the plurality of particles.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 5,
The image forming unit forms the graph showing the generation position of each particle on one axis and the distance of each particle on the other axis.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 6,
The image forming unit forms the graph expressing the distance of each particle in a color corresponding to the position where each particle is generated.
An ultrasonic diagnostic apparatus.