JP6530961B2 - 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, for example, since the heart changes its shape relatively widely over multiple phases within the period of diastolic movement, in the diagnosis of blood flow in the heart, the shape change of the heart or the heart chamber in the heart is neglected Can not do it.

  The present invention has been made in view of the background art described above, and its object is to realize a diagnosis in line with a change in shape of the heart when diagnosing blood flow in the heart.

  A preferred ultrasonic diagnostic apparatus meeting the above object is 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, and a blood flow vector. A particle operation unit for tracking the movement destination of each virtual particle of blood flow in the heart chamber, and an inflow line and an outflow line as a calculation reference line of the tracking in an ultrasonic image including the heart chamber And a reference line setting unit configured to set at least one of the set inflow line and the outflow line to follow the shape change of the heart chamber in the ultrasound 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, one or more in blood flow to be diagnosed Virtual particles are generated.

  In the above configuration, at least one of the inflow line and the outflow line is set as a calculation reference line for tracking the movement destination of each particle. For example, the inner region of the heart chamber and the outer region of the heart chamber are identified with reference to the inflow line and the outflow line, and the movement destination of each particle is tracked for the active calculation target of the inner region of the heart chamber. Of course, the outside region of the heart chamber may be set as a calculation target according to the contents of diagnosis and the like.

  In the above configuration, at least one of the inflow line and the outflow line is set to follow the shape change of the heart chamber in the ultrasound image. Thus, for example, with respect to a heart chamber whose shape changes relatively largely in multiple phases within the period of dilation / contraction movement, a reference line (inflow line and outflow line corresponding to the shape of the heart chamber in each time phase) At least one) can be set.

  According to the ultrasonic diagnostic apparatus having the above configuration, at least one of the inflow line and the outflow line is set to follow the shape change of the heart chamber in the ultrasonic image, so that, for example, at each time phase According to the shape of the heart chamber in the phase, it is possible to distinguish the inner region of the heart chamber and the outer region of the heart chamber. In evaluating or diagnosing the function of the heart, it is important that the state of blood flow (flow of blood) in the heart, for example, the state of blood flow that flows into and out of the heart chamber of the left ventricle of the heart. Become one of the important indicators. According to the above-mentioned device, for example, when diagnosing the state of the blood flow which flows into the heart chamber and flows out of the heart chamber, etc., the diagnosis in line with the shape change of the heart chamber becomes possible.

  In a desirable embodiment, the ultrasonic diagnostic apparatus sets two inflow feature points with respect to the heart chamber in the ultrasonic image, and the plurality of inflow feature points are changed according to the shape change of the heart chamber over multiple phases. The movement destination of one inflow feature point is tracked, and the reference line setting unit sets the inflow line connecting the two inflow feature points for each time phase over a plurality of time phases. And allowing the inflow line to follow the shape change of the heart chamber.

  In a desirable embodiment, the ultrasonic diagnostic apparatus sets two outflow feature points with respect to the heart chamber in the ultrasonic image, and according to the shape change of the heart chamber over a plurality of phases, the 2 The movement destination of one outflow feature point is tracked, and the reference line setting unit sets the outflow line connecting the two outflow feature points for each time phase over the plurality of time phases. And the outflow line is made to follow the shape change of the heart chamber.

  In a preferred embodiment, the ultrasonic diagnostic apparatus further includes a lumen line setting unit for setting a lumen line corresponding to the boundary between the heart chamber of the heart and the myocardium in the ultrasonic image, and the lumen line The two inflow feature points and the two outflow feature points are set on top.

  In a desirable embodiment, the lumen line setting unit forms the lumen line based on a plurality of sample points corresponding to the boundary between the heart chamber of the heart and the myocardium in the ultrasound image, and The shape of the lumen line is changed by moving the plurality of sample points so as to follow the shape change, and the reference line setting unit selects the two inflow feature points from among the plurality of sample points. The two outflow feature points are selected.

  In a desirable embodiment, the ultrasonic diagnostic apparatus is configured to perform the ultrasonic wave detection for each time phase at a plurality of generation points on the inflow line which follow the shape change of the heart chamber over a plurality of time phases in the ultrasonic image. The apparatus is characterized by further comprising a particle generation unit that generates a plurality of virtual blood flow particles.

  In a desirable embodiment, when the blood flow vector at each generation point on the inflow line is the inflow direction into the heart cavity, the particle generation unit generates one or more particles at the generation point. It is characterized by

  In a desirable specific example, the particle operation unit calculates coordinate values of the movement destination of each particle for each time phase over a plurality of time phases based on the blood flow vector, and coordinates of the movement destination of each particle Based on the value, it is determined whether or not the particle has passed through the outflow line, and tracking of the movement destination after the passage of each particle having passed through the outflow line is ended.

  According to the present invention, when diagnosing blood flow in the heart, it is possible to realize a diagnosis in line with the change in shape of 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 which shows the specific example of the two-dimensional 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 for demonstrating the other completion | finish conditions of movement destination calculation. It is a figure which shows the specific example of a trace line. It is a figure which shows the specific example of a blood-flow display image.

  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 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 image forming unit 20 forms frame data for a B-mode image based on, for example, a received signal of an ultrasonic wave 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 image forming unit 20. Further, the inflow / outflow line setting unit 44 sets an inflow line in the flow path of blood flow into the heart lumen in the image data, and sets an outflow line in the flow path of 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. A specific example of the image data 22 obtained in the image forming unit 20 is illustrated in FIG. 2, and in the image data 22 of FIG. 2, the lumen of the left ventricle of the heart is surrounded by the myocardium and the 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 (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 generates velocity information of the myocardium (heart wall) on the lumen line (symbol 52 in FIG. 2) based on the image data formed in the image forming unit 20. Do. 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 calculation unit 46 uses, for example, a lumen line by pattern matching using correlation calculation or the like based on pixel values (such as luminance values) of image data between frames of image data obtained over a plurality of frames. For each sample point above, 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 processing unit 80 is formed in the display processing unit 80, which forms a blood flow display image based on the image data of the ultrasonic image obtained from the image forming unit 20 and the calculation result obtained from the particle calculation unit 70. The blood flow display image 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 image forming unit 20, the Doppler processing unit 30, the velocity vector calculating unit 40, the lumen line setting unit 42, 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 processing unit 80 can be realized using hardware such as an electric / electronic circuit or processor, for example. A device such as a memory may be used as necessary in its 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 shown as a basic example (1) in FIG. 7, a plurality of particles arranged in an example at equal intervals are generated on an inflow line 54 connecting a start point S and an end point E by straight lines. 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.

  The particle generation unit 60 may generate a plurality of particles in only one specific frame (only one time phase), but it is desirable to generate a plurality of particles in each frame periodically over a plurality of frames. For example, in a vector frame sequence consisting of a plurality of vector frames (FIG. 5 (A)), a plurality of particles may be generated for each vector frame, or in the frame sequence after correction (FIG. 5 (B)) Multiple particles may be generated in the vector frame and in each interpolated frame. Of course, multiple particles may be generated in each frame at intervals of several frames.

  If the inflow line 54 is set by the inflow / outflow line setting unit 44 so as to follow the motion of the heart in the image data of the ultrasonic image, the plurality of particles are corrected while following the motion of the heart. Can be generated.

  Further, as shown as a modified example (2) in FIG. 7, the generation mode of the plurality of particles may be made different depending on the size and the direction of the velocity vector V on the inflow line 54. In the modification (2), the number of particles at the position of the velocity vector V is increased as the magnitude of the velocity vector V (for example, the perpendicular component to the inflow line 54) is larger. Further, in the modification (2), particles are generated at the position of the velocity vector V only when the velocity vector V is in the positive direction. The direction (positive or negative direction) to generate the particles may be set by the user, for example.

  Further, instead of the specific example shown in FIG. 7, the particle generation unit 60 may generate a plurality of particles, for example, on the curved inflow line 54 (see FIG. 3). Furthermore, not only on the inflow line 54, for example, a plurality of particles may be generated on the generation line designated by the user or in the generation region, for example, two-dimensionally equally in the region of interest (for example, in a grid) ) Multiple particles may be generated.

  FIG. 8 is a diagram showing a specific example of two-dimensional generation of a plurality of particles. An example in which a plurality of particles are generated two-dimensionally in the particle generation area G is illustrated in the specific example 1 of FIG. 8. For example, the position, shape, and size of the particle generation area G may be adjusted by the user. The shape of the particle generation area G shown in FIG. 8 is a rectangle, but the shape of the particle generation area G is a polygon other than a rectangle, a circle, an ellipse, etc. For example, an appropriate shape is selected according to the contents of diagnosis. It is also good. Further, it is desirable that the number, the density, and the like of the plurality of particles generated in the particle generation area G can be appropriately set by the user, for example. When the particle generation area G is set, the setting of the inflow line 54 (see FIG. 2) may be omitted.

  Furthermore, as shown in Example 2 of FIG. 8, a plurality of particles may be generated two-dimensionally and uniformly in the lumen line 52. Also in the second example, it is desirable that the user can appropriately set the number, density, and the like of the plurality of particles. Also in the second example, the setting of the inflow line 54 (see FIG. 2) may be omitted.

  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. 9 is a diagram for describing a specific example of calculation of the movement destination of each particle. FIG. 9 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. 9, 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. 9, since the moving 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. 10 is a diagram for explaining exception processing of operation of movement destination of each particle. Although the particle operation unit 70 derives the moving destination of each particle by the basic processing described using FIG. 9, as shown in FIG. 10, 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. 10, 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. 10, 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. 11 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. 9 and the exception processing described using FIG. 10, and as shown in FIG. 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. 11, 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. 11, the position P9 'is an 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

  FIG. 12 is a diagram for explaining another ending condition of the movement destination calculation. In the specific example shown in FIG. 12, when the movement destination of each particle enters the annihilation region, the calculation of the movement destination of the particle ends.

  The annihilation region is set outside the region of interest (constituted by the lumen line 52, the inflow line 54 and the outflow line 56) with the outflow line 56 as a boundary. Since the lumen line 52 and the outflow line 56 are set to follow the shape change of the heart chamber, the position and the shape of the annihilation region also follow the shape change of the heart chamber. Then, when the coordinate value of the movement destination of each particle becomes the coordinate value in the annihilation area, it is determined that the movement destination of the particle has entered the annihilation area, and the calculation of the movement destination of the particle ends. When the calculation of the movement destination of each particle is ended, the final movement destination of the particle immediately before the end is corrected on the outflow line 56 or in the vicinity thereof as in the case of the specific example shown in FIG. It is desirable to do.

  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 across multiple time phases (multiple frames) of each particle, the display processing unit 80 calculates the multiple times A bloodstream display image is formed showing in the image the coordinates of the destination of each particle across the phase. The display processing unit 80 forms, for example, an image of a trajectory in which the coordinates of the movement destination of each particle in a plurality of time phases are indicated by a locus of at least one of a point and a line.

  FIG. 13 is a diagram illustrating a specific example of the trajectory. One trajectory L relating to the particle P, which is one of a plurality of particles, is illustrated in FIG. The trajectory L corresponds to the movement destination (plural time phases) of the particles P calculated one after another over plural time phases (multiple frames) in the frame sequence after correction (FIG. 5B, FIG. 6) Of multiple positions). For example, moving destinations (for example, positions P 0, P 1, P 2, P 3, P 4, P 5,... In FIG. 9) of particles P in multiple time phases are connected by a straight line or curve (for example, curve based on spline interpolation) in time phase order Thus, the trajectory L is formed. In addition, in place of the trajectory L or in place of the trajectory L, a plurality of movement destinations (for example, positions P0, P1, P2, P2, P3, P4, P5,... Of FIG. It may be displayed in a column by points.

  In addition, it is desirable that the length of the displayed trace L be appropriately adjusted. For example, the display processing unit 80 forms the trajectory L from the time phase (current phase) in which the trajectory of each particle is displayed to the time phase (remaining time phase) before a predetermined time. That is, as in the specific example shown in FIG. 13, a portion of the trajectory L from the position Pn of the particle P in the current phase to the remaining time phase before the current phase by a predetermined time as the trajectory L of the particle P Only (solid line portion) is displayed, and a portion (broken line portion) of the trajectory L formed before the remaining time phase is not displayed. Furthermore, it is desirable that the user can set a predetermined time. For example, when the user operates a key provided to the operation device 90, the user may be able to determine the predetermined time in units of 100 ms within the settable range of 100 ms to 1000 ms.

  The display processing unit 80 may display, for example, only a portion of the trajectory L from the time phase in which each particle is generated to the time phase after a predetermined time.

  FIG. 14 is a diagram showing a specific example of a blood flow display image. The display processing unit 80 forms a trajectory L for each of the plurality of particles, and for example, displays a blood flow indicating the trajectory L of the plurality of particles on the ultrasound image of the heart obtained from the image forming unit 20 Form an image. In addition, a blood flow display image may be formed on the color Doppler image formed by using the Doppler information obtained from the Doppler processing unit 30 and showing the trajectory L of the plurality of particles. The blood flow display image formed in the display processing unit 80 is displayed on the display unit 82.

  Moreover, the display number of the trajectory L may be thinned without displaying all of the plurality of trajectory L corresponding to all the generated particles. For example, by displaying only one out of every ten lines L formed, it is possible to eliminate the congestion of many lines L in the blood flow display image and to form an easy-to-see image. May be Furthermore, for example, when the user operates a key provided to the operation device 90, the user may be able to set the number of trace L to be displayed or the thinning rate.

  The display processing unit 80 forms a blood flow display image for each display time phase over a plurality of display time phases. For example, a blood flow display image (FIG. 14) corresponding to the display phase is formed on an ultrasound image or a color Doppler image of the heart corresponding to each display phase. Thereby, while confirming movement of the heart dynamically changing over multiple time phases with an ultrasonic image or a color Doppler image, it is visually observed that trajectories L of multiple particles change over multiple time phases. And can be checked dynamically. Of course, a still image (freeze image) at a specific cardiac phase (such as end diastole or end systole) desired by the user may be displayed. This makes it possible to visually and intuitively confirm, for example, the state of blood vortex, turbulence, stagnation, etc. in the heart.

  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 image forming unit 30 Doppler processing unit 40 velocity vector calculating unit 42 lumen line setting unit 44 inflow / outflow line setting unit 46 lumen line speed calculating unit 50 interpolation processing unit 60 particle generation unit, 70 particle operation unit, 80 display processing unit, 100 control unit.

Claims (8)

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 operation unit for tracking the destination of virtual particles of blood flow in the heart chamber based on the blood flow vector;
In the ultrasound image including the heart chamber, at least one of the inflow line and the outflow line is set as a calculation reference line of the tracking, and at least one of the set inflow line and the outflow line is the heart in the ultrasound image. A reference line setting unit for following the shape change of the cavity;
In order to form an image of a trajectory in which the coordinates of the movement destination of each particle in a plurality of time phases are indicated by a locus of at least one of a point and a line, a predetermined time before the time phase when the locus of each particle is displayed A display processing unit that forms an image of the trajectory until the time phase of
Have
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 1,
Two inflow feature points are set for the heart chamber in the ultrasound image, and the movement destinations of the two inflow feature points are tracked according to the shape change of the heart chamber over multiple phases;
The reference line setting unit sets the inflow line connecting the two inflow feature points for each time phase over a plurality of time phases, thereby changing the shape of the heart cavity over a plurality of time phases. Make the inflow line follow
An ultrasonic diagnostic apparatus characterized by The ultrasonic diagnostic apparatus according to claim 1 or 2
Two outflow feature points are set for the heart chamber in the ultrasound image, and the movement destinations of the two outflow feature points are tracked according to the shape change of the heart chamber over multiple phases.
The reference line setting unit sets the outflow line connecting the two outflow characteristic points for each time phase over a plurality of time phases, thereby changing the shape of the heart cavity over a plurality of time phases. Make the outflow line follow
An ultrasonic diagnostic apparatus characterized by The ultrasonic diagnostic apparatus according to any one of claims 1 to 3 .
And a lumen line setting unit for setting a lumen line corresponding to the boundary between the heart chamber of the heart and the myocardium in the ultrasonic image.
When the movement destination of each particle exceeds the lumen line from the lumen line, the particle operation unit places the movement destination of each particle on the lumen line or near the heart cavity side of the lumen line. Fix,
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 4,
The lumen line setting unit forms the lumen line based on a plurality of sample points corresponding to the boundary between the heart chamber of the heart and the myocardium in the ultrasound image, and follows the shape change of the boundary. Changing the shape of the lumen line by moving the plurality of sample points as
The reference line setting unit selects the more of either et two inflow characteristic points of the sample points and two outflow characteristic points,
An ultrasonic diagnostic apparatus characterized by The ultrasonic diagnostic apparatus according to any one of claims 1 to 5.
At the plurality of generation points on the inflow line following the shape change of the heart chamber over the plurality of time phases in the ultrasonic image, the plurality of virtual particles of the blood flow are generated for each time phase. It further has a particle generation unit,
An ultrasonic diagnostic apparatus characterized by In the ultrasonic diagnostic apparatus according to claim 6,
When the blood flow vector at each generation point on the inflow line is the inflow direction into the heart cavity, the particle generation unit is configured to generate the number of particles according to the size of the blood flow vector at the generation point. Produce one or more particles,
An ultrasonic diagnostic apparatus characterized by The ultrasonic diagnostic apparatus according to any one of claims 1 to 7.
The particle operation unit calculates coordinate values of movement destinations of the particles for each time phase over a plurality of time phases based on the blood flow vector, and based on the coordinate values of movement destinations of the particles. It is determined whether particles have passed through the outflow line, and tracking of the movement destination after the passage of each of the particles passing through the outflow line is ended.
An ultrasonic diagnostic apparatus characterized by

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