JP3210088B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus provided with a so-called color flow mapping (CFM) method for displaying a spatial spread of a blood flow velocity in a heart or a blood vessel.

[0002]

2. Description of the Related Art Information on the blood flow in the heart or blood vessels is referred to as 2.
A method of obtaining a dimensional spread image (hereinafter, referred to as a “blood flow image”), a so-called color flow mapping (CFM) method, utilizes the Doppler effect of ultrasonic waves. That is, when the ultrasonic beam transmitted into the living body is reflected by the moving reflector (blood cells), the frequency (reception frequency) of the reflected wave shifts according to the moving speed of the blood cells as compared with the transmission frequency. (Doppler effect) is used to obtain a distribution of the shift frequency (Doppler signal), that is, a blood flow image having a spatial spread.

Normally, blood vessels exist in a living body vertically and horizontally, that is, three-dimensionally. However, the blood flow image is a two-dimensional image corresponding to the scanning plane of the ultrasonic beam. So 3
Part of the blood flow of the blood vessels that exist in a dimension,
That is, only the blood flow at the portion intersecting the scanning plane is displayed fragmentarily, and the entire blood flow over a wide range of the blood vessel cannot be recognized by one blood flow image. Therefore, the state of the entire blood flow of the blood vessel has been recognized using the following method.

That is, by changing the direction of the ultrasonic probe or moving the contact position of the ultrasonic probe with the living body, the scanning plane is changed, and a plurality of blood flow images having different scanning ranges are obtained. By looking at these blood flow images individually, the state of the entire blood flow was inferred. However, this method has the following problems.

(1) In order to analogize the state of the entire blood flow, the diagnostician requires sufficient anatomical knowledge and very skill, and the degree of recognition of the state of the entire blood flow is determined by the diagnosis. It is highly dependent on the anatomical knowledge and skill of the individual.

[0006] (2) Since the anatomical knowledge obtained by the diagnosing person is mainly related to the normal state (normal state), it is difficult to analogize an abnormal part outside the range of the anatomical knowledge. is there.

(3) In order to analogize the state of the whole blood flow, it is necessary to determine at which position in the living body and in what direction the ultrasonic probe is brought into contact with each of the plurality of blood flow images. You need to know, However, only the operator (diagnostic person) who actually engaged in the operation of the ultrasonic probe knows the position and direction, and even if another person views multiple blood flow images, Since the other person does not know the position and direction, it is difficult to estimate the state of the entire blood flow. In addition, even if a plurality of blood flow images are stored on a video tape or the like, and the person views the plurality of blood flow images at a later date, the state of the entire blood flow estimated when the plurality of blood flow images were obtained. Is questionable.

(4) In connection with the content of the above (3), the state of the whole blood flow is obtained by acquiring a plurality of blood flow images in the head of the operator (diagnostic person) who was involved in operating the ultrasonic probe. It is very difficult for the person to communicate the state of the whole blood flow to a third party because of the analogy to the base.

As described above, the conventional means for recognizing the state of the entire blood flow has no objectivity such as transmissibility and recordability. Therefore, development of a means for recognizing the state of the entire blood flow having objectivity has been desired.

On the other hand, there are the following three-dimensional display methods of blood vessels currently used. That is, a surface display method of a part of interest in an image acquisition apparatus such as an X-ray CT apparatus or a magnetic resonance imaging (MRI) apparatus, a three-dimensional display method by volume rendering, and a catheter in an X-ray imaging apparatus having two focal points. A method of injecting a contrast agent into a blood vessel by using the method, obtaining two types of images for both the left and right eyes only of a portion (blood vessel) where the contrast agent exists, and displaying the two types of images in stereo, and a blood vessel in MR angio Rotation display method. However, according to any of the methods, only information on the presence of blood vessels is obtained, and information on blood flow cannot be obtained.

In the ultrasonic diagnostic apparatus for obtaining a two-dimensional image, the scanning plane is changed by changing the direction of the ultrasonic probe or moving the contact position of the ultrasonic probe with the living body. A method of detecting the position of the probe, obtaining a plurality of two-dimensional blood flow images having different scanning ranges from each other, obtaining a three-dimensional image from the obtained two-dimensional blood flow images, and displaying the three-dimensional image in three dimensions has been considered. I have.
However, in this method, since the three-dimensional display is performed after the operation of the ultrasonic probe is completed, if the desired three-dimensional image cannot be obtained, the diagnosis must be performed again, and the three-dimensional blood flow image is displayed in real time. There was a drawback that it could not be seen in.

[0012]

As described above,
In the conventional ultrasonic diagnostic apparatus, three-dimensional information of blood flow having objectivity such as transmissibility and recordability cannot be obtained in real time. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an ultrasonic diagnostic apparatus capable of displaying a three-dimensional image in real time.

[0013]

Means for Solving the Problems Claim 1 according to the present invention.
The described ultrasonic diagnostic apparatus, in order to achieve the above object,
An ultrasonic probe for transmitting an ultrasonic wave into the subject and receiving an echo signal from the subject, a unit for obtaining movement information of a moving body in the subject based on the echo signal, Means for detecting at least one of the position and the direction of the probe and obtaining position information of the moving body in a three-dimensional space based on the detection result; and a three-dimensional image of the movement information based on the movement information and the position information. Memory for storing distribution data, operation means for performing operations related to holding and updating of images, state for holding three-dimensional distribution data stored in the memory, and three-dimensional distribution data stored in the memory Means for switching the state of updating partially based on the movement information and the position information in accordance with an input to the operation means, and projecting from a plurality of directions shifted by a predetermined angle. A two-dimensional image, characterized by comprising a three-dimensional image display means for continuously displaying the order determined in real time from three-dimensional distribution data stored in the memory was. In order to achieve the above object, an ultrasonic diagnostic apparatus according to claim 2 of the present invention scans the inside of a subject with ultrasonic waves to obtain an echo signal, and obtains an echo signal for a B-mode image based on the echo signal. Means for obtaining movement data of the moving object in the subject based on the echo signal, operation means for performing operations related to holding and updating of an image, and means for operating the B-mode image. Means for displaying a two-dimensional tomographic image obtained based on the data and the movement information; a memory for storing three-dimensional distribution data of the movement information based on the movement information; A three-dimensional image display means for obtaining a two-dimensional image projected from a plurality of directions displaced by a predetermined angle from the two-dimensional distribution data and sequentially displaying the two-dimensional images sequentially; In a state in which the update, the 2
Means for switching between a state in which the three-dimensional distribution data is updated in real time and a state in which the three-dimensional distribution data is held without being updated, according to an input to the operation means.

[0014]

According to the present invention, movement information of a moving object in response to an echo signal from the moving object obtained by performing an ultrasonic beam scan on a desired three-dimensional space in the subject, and the movement information A three-dimensional distribution of the movement information of the moving object from the position information in the three-dimensional space, and updates the three-dimensional distribution each time the ultrasonic beam scan is performed; A plurality of two-dimensional images obtained by projecting from the camera are displayed in real time in a predetermined order, and an image capable of three-dimensionally recognizing the state of the entire blood flow by a human visual characteristic called “motion parallax”. Obtainable. As described above, a three-dimensional image can be obtained in real time.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The scanning method of the ultrasonic probe includes linear scanning, sector scanning and the like, and the scanning means is manual scanning, mechanical scanning,
There is electronic scanning, and any of them may be employed. However, the following description is based on the assumption that the sector electronic scanning method is employed.

The ultrasonic diagnostic apparatus according to the first embodiment shown in FIG. 1 has a system controller 13 as a control center of the whole system, and a position detecting circuit 1, an ultrasonic probe 2, a transmitting system 3, a receiving system 4, B Mode processing system 5, color flow mapping (CFM) processing system 6, digital scan converter (DSC) 7, three-dimensional digital scan converter (3D-DSC) 8, two-dimensional display system 9, three-dimensional display system 10, operation switch 12 Is provided.

The ultrasonic probe 2 includes a plurality of piezoelectric vibrators arranged side by side. When the ultrasonic probe 2 is driven to transmit by the transmission system 3, it transmits ultrasonic pulses to the subject P, and the blood flowing in the subject P Receives echo signals with Doppler shift due to flow. Since the scanning method of the ultrasonic probe 2 is the sector electronic scanning method as described above, the scanning surface is a fan-shaped two-dimensionally spread plane. Here, the echo signal obtained from one scanning plane is referred to as scanning data. This ultrasonic probe 2
Is brought into contact with the body surface 20 of the subject P as shown in FIG. 3 so that the direction of the scanning plane can be changed in various ways. By changing the direction of the scanning plane, a plurality of scan data within a desired three-dimensional range (hereinafter, referred to as “real space”) of the subject P is obtained, and the data having a three-dimensional spread is obtained by the plurality of scan data. Volume data) is generated. Here, the operation of the ultrasonic probe 2 for changing the direction of the scanning plane may be performed manually or may be performed by mechanical means. In this embodiment, the operation of the ultrasonic probe 2 is performed manually. Here, the operation of the ultrasonic probe 2 for obtaining a plurality of scan data is referred to as a three-dimensional scan.

The position detecting circuit 1 determines the position of the ultrasonic probe 2 in each scanning plane, the scanning plane direction, specifically, the positions x, y, and z shown in FIG. (Referred to as "data position information"), and supplies this scan data position information to the 3D-DSC 8. FIG. 5 shows an external view of a three-dimensional position detection arm 20 as an example of this position detector.
The ultrasonic probe 2 is attached to the tip of the arm 21, and several positions of the arm 21 (one axis, two axes, three axes,
Axes, 5 axes, and 6 axes) are rotatably connected to each other, and position information is obtained based on the rotation angles. The scan data position information is obtained by converting the two-dimensional blood flow information (hereinafter referred to as “CFM data”) obtained through the CFM processing system 6 into the X, Y, and Z coordinates of the 3D-DSC 8 corresponding to the real space. It is used to calculate an address when generating volume data by distributing it in the original three-dimensional memory range (hereinafter referred to as “three-dimensional memory space”), which will be described later in detail.

The transmission system 3 includes a pulse generator 3A, a transmission delay circuit 3B, and a pulser 3C. In the transmission system 3, the pulse generator 3A generates a rate pulse and sends the rate pulse to the transmission delay circuit 3B. The transmission delay circuit 3B gives a predetermined delay time to each of the transducers so as to converge the ultrasonic beam in a predetermined direction with respect to the rate pulse received from the pulse generator 3A, and sends the delay rate pulse to the pulser 3C. . The pulser 3C repeatedly drives each transducer of the ultrasonic probe 2 a predetermined number of times based on the delay rate pulse received from the transmission delay circuit 3B.

A receiving system 4 for receiving an echo signal obtained by transmitting and receiving the ultrasonic wave includes a preamplifier 4A, a reception delay circuit 4B,
An adder 4C is provided. In the receiving system 4, the preamplifier 4A amplifies the echo signal to a predetermined level, and sends out the amplified signal to the reception delay circuit 4B. The reception delay circuit 4B gives a delay time to each of the transducers that restores the delay time given by the transmission delay circuit 3B to the amplified signal received from the preamplifier 4A. The adder 4C adds and combines the signals from the respective vibrators passed through the reception delay circuit 4B, and combines the added and combined signal with the B-mode processing system 5 and the C-mode signal.
The data is sent to the FM processing system 6.

The B-mode processing system 5 includes a logarithmic amplifier 5A, an envelope detection circuit 5B, and an A / D converter 5C, and performs the following processing under the control of the system controller 13. That is, in the B-mode processing system 5, the logarithmic amplifier 5A
A logarithmically amplifies the signal received from the adder 4C of the receiving system 4 and sends it out to the envelope detection circuit 5B. Envelope detection circuit 5
B detects the envelope of the output of the logarithmic amplifier 5A,
This detection output is sent to the A / D converter 5C. Therefore A
The detection output from the envelope detection circuit 5B is converted into a digital signal in the / D converter 5C, and is output to the DSC 7 as B-mode image data.

On the other hand, the CFM processing system 6 includes a phase detection circuit 6
A, A / D converter 6B, MTI (Moving-Tar)
A get-Indicator) filter 6C, an autocorrelator 6D, and an operation unit 6E are provided, and perform the following processing under the control of the system controller 13. That is, CF
In the M processing system 6, the transfer detection circuit 6A receives a signal from the adder 4C of the reception system 4, performs quadrature phase detection on the signal, removes high-frequency components by a low-pass filter (not shown), and outputs a Doppler shift signal. That is, a Doppler detection output for a blood flow image is obtained. The Doppler detection output includes unnecessary reflected signals (clutter components) from slow-moving objects such as the heart wall in addition to blood flow information. Therefore, the Doppler detection output is converted into a digital signal by the A / D converter 6B and passes through the MTI filter 6C. Here, MTI is a technology used in radar, and as described above, Moving-Target-Indica
It is an abbreviation of tor , and is a method of detecting only a moving target using the Doppler effect. Therefore, the MTI filter 6C
Detects only the movement of the blood flow based on the phase change between the same pixels in the rate pulse repeatedly transmitted a predetermined number of times, and removes the clutter component from the Doppler detection output.

The autocorrelator 6D analyzes the frequency of the signal from which the clutter component has been removed in real time for each two-dimensional multipoint. The number of operations in the frequency analysis by the autocorrelator 6D is much smaller than the number of operations in the FFT (fast Fourier transform) method, so that real-time processing has become possible. The operation unit 6E receives the output of the autocorrelator 6D, and includes an average speed operation unit, a dispersion operation unit, and a power operation unit. In this calculation unit 6E, the average speed calculation unit obtains the average Doppler shift frequency fd, and the variance calculation unit calculates the variance σ ² , And the power calculation unit calculates the total power TP. The total power TP is proportional to the intensity of the scattered echo from the blood flow, but the echo component from the moving object corresponding to the cut-off frequency of the MTI filter 6C or lower is removed. This average Doppler shift frequency fd, variance σ ² , C consisting of total power TP
FM data is obtained for each scan data, and DSC7 and 3D-
Output to DSC8. Here, the CFM data supplied to the 3D-DSC 8 will be described. The CFM data includes the following three types of values (voxel values) according to the presence or absence of blood flow and the direction of blood flow. That is, a value “1” indicating that there is no blood flow, a value “2” indicating that the blood flow direction is toward the probe, and a value indicating that the blood flow direction is away from the probe. "3". DSC
Numeral 7 outputs the output of the B-mode processing system 6 and each image data input from the CFM processing system 6 to the display system 9 in accordance with the scanning method of the color monitor 9C described later.

The 3D-DSC 8 receives the output of the CFM processing system 6, distributes a plurality of CFM data obtained by three-dimensional scanning in a three-dimensional memory space, generates volume data, and uses the volume data. To generate a plurality of projection image (two-dimensional image) data from a plurality of projection directions, and supply the plurality of projection image data to the three-dimensional display system 10 in a predetermined order.

FIG. 2 is a block diagram showing the configuration of the 3D-DSC 8. 3D-DSC8, as shown in FIG.
It has a volume memory (VM) 8A, an address controller 8B, a maximum value filter 8C, an intermediate buffer 8D, a coordinate rotation unit 8E, a Z buffer algorithm unit 8F, a projection image memory 8G, and a 3D-DSC controller 8I.
Volume memory (VM) 8A in 3D-DSC8
Has a three-dimensional memory space corresponding to the real space, and distributes a plurality of CFM data input from the CFM processing system 6 in this three-dimensional memory space to generate volume data. The volume data is cleared before the start of the three-dimensional scan. The three-dimensional memory space has a plurality of voxels, which are minute stereoscopic pixels. The distribution of the CFM data is performed according to a write address signal supplied from the address controller 8B. The address controller 8B inputs the scan data position information input from the position detection circuit 1, and mainly uses the scan data position information to generate the VM data.
The write address of the CFM data in the three-dimensional memory space of 8A is calculated, and the write address is supplied to the VM 8A at an appropriate timing. Here, if there is data of the same address in the three-dimensional memory space (which occurs when a three-dimensional scan is performed so that the scanning planes overlap),
Select the one with the larger voxel value. This means that even if the data is obtained from the inside of a blood vessel, the data does not include a Doppler component at a specific timing (diastole) of the heartbeat, that is, the above-mentioned blood flow is set to “1”. There are cases (Doppler disappearance). Data with a large value is selected in order to prevent Doppler disappearance as much as possible.

The maximum value filter 8C is a so-called interpolation circuit. That is, voxel data at a point (interpolation point) to which no data is supplied despite being within the three-dimensional scan range in the three-dimensional memory space is interpolated.
This interpolation is performed by convolution in an N × N × N field. However, N is set to be larger than the number of interpolation points included in this field. This interpolation processing is performed as follows. Here, assuming that the coordinates of the interpolation point in the three-dimensional memory space are vm (x, y, z), the coordinate range of the voxel data included in the field is vm (xi, y
-j, zk). However, -N / 2 ≦ i ≦ N / 2, −N
/ 2 ≦ j ≦ N / 2 and −N / 2 ≦ k ≦ N / 2. Then, the maximum voxel value in vm (xi, yj, zk) is applied to the interpolation point vm (x, y, z). The volume data interpolated by the maximum value filter 8C is supplied to the intermediate buffer 8D. The intermediate buffer 8D has the same three-dimensional memory space as the VM 8A, and stores the volume data VD interpolated by the maximum filter 8C.

FIGS. 6 and 7 are views schematically showing operations for obtaining a plurality of types of projection images. Next, FIG. 2, FIG. 6 and FIG.
The operation of this embodiment will be described with reference to FIG. The coordinate rotation unit 8E and the Z buffer algorithm unit 8F obtain a plurality of projection image data obtained from a plurality of projection directions from the volume data VD stored in the intermediate buffer 8D. Here the volume data VD is rotated about the y-axis and parallel projection rotation axis AR to specify the operator in the coordinate rotating portion 8E in the direction of arrow a ₄ every predetermined angle [theta] d. Here, assuming that the coordinates before rotation are (x0, y0, z0) and the coordinates after rotation of the angle θd are (x, y, z), the relationship is as follows. x0 = x · cos θd + z · sin θd (1) y0 = y (2) z0 = x · (−sin θd) + z · cos θd (3) Based on this relationship, the volume data VD is changed for each angle θd. Rotate.

The Z-buffer algorithm section 8F creates a projection image every time the volume data VD rotates by an angle θd. As shown in FIG. 6, the projection method is as follows: a xy plane of the volume data VD via a projection plane SF from a predetermined position (viewpoint) VP fixed on the plus side on the z-axis, in this case, in the three-dimensional memory space. , A number of projection rays (rays) are defined, and for each ray, specific voxel data existing on that ray is extracted. The voxel data to be extracted is specified as follows. If all the voxel data on the ray is outside the three-dimensional scan range, that is, if the voxel value remains zero, the pixel value on the projected image for that ray is set to “0”. The pixel value “0” is displayed in, for example, green when displayed. Next, assuming the voxel values of the voxel data on the ray in order from the viewpoint VP side toward the xy plane, the voxel data having the voxel value of “2” or “3” appearing first is extracted, and the voxel value is calculated as The pixel value on the projected image related to the ray. If there is no “2” or “3” in the voxel data on the ray and there is “1”, “1” is set as the pixel value on the projection image for this ray. These pixel values “1”, “2”, and “3” are displayed in black, red, and blue when displayed.

Further, the Z buffer algorithm unit 8F includes:
A brightness value (brightness value) is given to the projection image according to the distance in the z-axis direction from the viewpoint VP. By giving this luminance value, a sense of perspective can be expressed on the monitor. Here, each x, y, z that can be taken in the three-dimensional memory space
It is assumed that the coordinate range on the axis is -126 to 126, and the coordinates of a certain pixel on the projected image are (xa, ya, za). If the pixel values are “0” and “1”,
No luminance value is given for that pixel. When the pixel value is “2”, 128 is added to za, and when the value of the pixel is “3”, the value of which is the pixel value of the pixel is “3”, 384 is added to za, and the value is added to that value. Let be the pixel value for the pixel. That is, the output from the Z buffer algorithm unit 8F is "0",
It takes one of the values "1", "2-254", and "258-510".

The projection memory 8G has a plurality of plane memories (PM) 8G1, 8G2... 8Gm. The projection image data stored in each plane memory is predetermined. For example, the plane memory 8G1 stores the projection image G obtained first.
1 and the plane memory 8G2 stores the projection image G
2 is stored in the plane memory according to the order in which the projection images are obtained. At the time of output, the projection image G1 stored in the plane memory 8G1 is output, then the projection image G2 stored in the plane memory 8G2 is output, and so on. This continuous output operation is repeatedly performed under the control of the 3D-DSC controller 8I until the operator designates termination. The output from the projection memory 8G can be variously changed by the operator's instruction from the operation switch 12. The change in the output is, for example, stopping at a desired projection image, changing the display interval by changing the output interval, or enlarging or reducing a desired portion.

The two-dimensional display system 9 displays CFM image data or B-mode image data supplied from the DSC 7. The three-dimensional display system 10 performs color processing on the projection image data supplied from the 3D-DSC 8 and displays the data. The three-dimensional display system 10 includes a color processing circuit 10A, a D / A converter 1
0B and a color monitor 10C. The color processing circuit 10A gives hue and luminance according to each pixel value of the projection image data.

The D / A converter 10B is a color processing circuit 1
The output from 0A is converted to analog and the color monitor 10C
Displays projection image data. A conventional B mode or CFM image is displayed on the color monitor 9C, and a projected image is simultaneously displayed on the color monitor 10C in real time. The processing format of the color processing circuit 10A is RG
The B format shall be used. Of course, other formats may be used. Each pixel value of the projection image data supplied from the 3D-DSC 8 is classified into four types according to the state of the blood flow as described above, and the pixel value of the portion where the blood flow is present is constant according to the distance from the viewpoint. Has a range of
The hue is determined by the type of the pixel value, and the brightness is determined by the magnitude of the pixel value. That is, if the pixel value is “0”, it is green, if it is “1”, it is black, and “2”
R (red) signal, G (green) signal, B (blue) so as to be red in the case of "254" and blue in the case of "258 to 510".
Signal, and if the pixel value is in one of the ranges of “2-254”, the brightness of each pixel is set such that the pixel value “254” has the maximum brightness and the pixel value “2” has the minimum brightness. Set. If the pixel value is “25”
8 to 510 ”.
The luminance of each pixel is set so that the maximum luminance is set at "10" and the minimum luminance is set at the pixel value "258". Next, the operation of the present embodiment apparatus configured as described above will be described.

FIG. 3 is a diagram showing an example of a three-dimensional scan. An alternate long and short dash line indicates an operation direction of a plurality of scan data. As shown in FIG. 3, the ultrasonic probe 2 is brought into contact with the body surface 20 of the subject P, and the contact point (the ultrasonic radiation point P0)
3), the three-dimensional scan is performed while tilting or rotating in the directions indicated by arrows a1, a2 and a3. Here, the inclination of the ultrasonic probe 2 in the direction of arrow a1 is represented by an angle θ, and similarly, the inclination of the ultrasonic probe 2 in the direction of arrow a2 is represented by an angle φ,
The rotation in the direction of arrow a3 is represented by angle ψ. The angle between the raster at the end of one scanning plane and each raster (the divergence angle of the ultrasonic beam) is represented by ω.

By this three-dimensional scan, an echo signal from a three-dimensional scan range in a desired real space (three-dimensional space) of the subject P can be obtained. Here, in order to reduce the influence of the heart beat, scanning may be performed according to the heart beat cycle. This echo signal is supplied to a B-mode processing system 5 and a CFM processing system 6 via a reception system 4, and a B-mode image and a CFM image are obtained for each scanning plane. The B-mode image data and the CFM data are sent to the DSC 7, and the CFM data is sent to the 3D-DSC 8.

All CFM data obtained by three-dimensional scanning (one CFM data corresponds to one scanning plane)
Is supplied to the 3D-DSC8. FIG. 4 shows 3D-DSC
FIG. 8 is a diagram showing a state of distribution of CFM data in an eight-dimensional memory space SV. Position and rotation angle of the ultrasonic probe 2, that is, scan data position information (position x, y, z
And angles θ, φ, ψ) are determined by the position detection circuit 1 for each scanning plane.
And the address controller 8 of the 3D-DSC 8
B. The angle θ is 3 in the three-dimensional memory space SV.
The angle between the y-axis of the three-dimensional memory space SV and the center line CL of the scanning plane, the angle φ is the angle between the x-axis and the center line CL of the scanning plane, and the angle φ is the rotation angle of the scanning plane. . The angle information determines the range of the scanning plane in the three-dimensional memory space SV, and furthermore, the swing angle ω of each raster, the depth of each point in the scanning plane, and the coordinates of the ultrasonic radiation point P0 in the three-dimensional memory space SV. Thus, an address in the three-dimensional memory space SV for each point of the CFM data is obtained.

The CFM data is sent one by one from the CFM processing system 6 and stored in a predetermined position on the volume memory VM by the address controller 8B based on the position data at that time. The volume data is interpolated by passing through the maximum value filter 8C,
D. A plurality of projection image data is obtained using the volume data VD. Here, the projection image creation operation is started after setting the position of the projection rotation axis, the position of the viewpoint, and the angle θd. This setting is input from the operation switch 12. By changing the position of the projection rotation axis and the setting of the viewpoint position, projected images from various directions can be obtained and displayed.

FIGS. 6 and 7 are diagrams showing the operation of creating a plurality of projection image data. The volume data VD is turned around the projection rotation axis AR parallel to the y axis by an arrow a4 in the coordinate rotation unit 8E.
, And is projected by the Z-buffer algorithm unit 8F on the projection plane SF in the three-dimensional memory space SV based on the viewpoint VP.
Information according to the distance in the z-axis direction from is added. This information is information corresponding to the luminance at the time of display. This angle θd is preferably set to about 11.25 degrees,
In this case, 32 projection images can be obtained during one rotation of the volume data VD. Here, the projection image data obtained when the rotation angle of the volume data VD is the angle θd is G
If the projection image data obtained at an angle of 2θd is G2 and the projection image data obtained at an angle of 32θd is G32, each of the projection image data G1, G2.
, Projection image data G1 is output first, and then G1
2 is output, and is continuously output and displayed at time intervals specified by the operator up to G32. If this time interval is set so that the time required to display the 32 types of projected images as one cycle is 1 second, the 32 types of projected images can be displayed as an animation image that rotates very smoothly. .

FIG. 7 is a conceptual diagram showing continuous display of a plurality of projection images. In FIG. 7, four types of projected images are obtained for convenience of explanation. Arrow Q1 shown in FIG.
Each of Q2, Q3, Q4 corresponds to the projection direction when obtaining the projection images G1, G2, G3, G4. Also, the volume data V
D represents three-dimensionally arranged blood vessels Pa and P as shown in the figure.
b, and it is assumed that the blood flow directions of the blood vessels Pa and Pb are directions indicated by arrows Sa and Sb. The projection images G1, G2, G3, G4 are obtained by rotating the volume data VD and changing the projection direction to a predetermined angle θd, here 9
Obtained every 0 degrees. The projection images G1, G2, G3, and G4 are displayed with a sense of perspective such that the front portion is displayed bright and the rear portion is displayed dark because the luminance information is added. Further, since the blood flow directions of the blood vessels Pa and Pb are opposite, the blood flow image Pb 'is displayed in red, for example, and the blood flow image Pa' is displayed in blue. Other parts without blood flow are displayed in black, and parts outside the scan range are displayed in green. These projected images G1, G
2, G3, G4 are displayed continuously in the order of G1, G2, G3, G4. With this continuous display, the diagnostician can recognize as if the three-dimensional model of the blood vessel is rotating. As a result, the three-dimensional state of the blood flow of the blood vessels Pa and Pb can be recognized without analogy by the diagnostician, and can be easily transmitted to a third party because there is no need for analogy. The state of rotation can be recorded as an animation image. In FIG. 7, the projection image viewed from the direction of Q5 is as shown by G5.

The operation of the apparatus of this embodiment described above is based on CF
Since the operation is performed at a very high speed independently of the input of the M data, the three-dimensional display using the rotational projection image is performed from the time when the three-dimensional scan is not completed. At the beginning of the three-dimensional scan, only a part of the whole is visible, but as the three-dimensional scan is performed, the whole image of the three-dimensional space becomes visible.

The currently scanned tomographic image is always displayed in real time on the color monitor 9C. 3
The dimensional display is displayed on the color monitor 10C. The operator can adjust the movement of the probe so as to obtain an optimal three-dimensional image while viewing the two monitors.

If the operator determines that a desired three-dimensional image cannot be obtained on the way, the three-dimensional scan can be interrupted by the operation switch 12 and the operation can be restarted from the beginning.

The operation switch 12 is provided with a freeze switch. When the freeze switch is turned on, scanning is stopped and the image is held at that time. In this embodiment, three freeze switches (FS1, FS2, FS3) are provided. When any one of these three switches is pressed, the other switches are released. When the FS1 is ON, the scanning is stopped and the two-dimensional image and the three-dimensional image are held at that time. The held three-dimensional image is rotated and displayed. F
When S2 is ON, only the three-dimensional image is held, the scan is continued, and the latest two-dimensional image is displayed. FS
When 3 is on, the latest image is displayed for both the two-dimensional image and the three-dimensional image. Next, how to use these freeze switches will be described.

First, FS2 is pressed to freeze only a three-dimensional image. Next, a three-dimensional image clear switch (not shown) provided on the operation panel 12 is pressed to initialize the three-dimensional image. The range of the three-dimensional scan is determined while observing the two-dimensional image, and the probe is brought to the first scan position. Then, press FS1 and the real-time 2
Observing 3D images and real-time 3D images
Perform a dimensional scan. When the three-dimensional scan is completed, the user presses FS2 to freeze the three-dimensional image. Although the whole is observed with a three-dimensional image, it may be difficult to observe a detailed part only with the three-dimensional image. Therefore, while observing the frozen three-dimensional image, the ultrasonic probe can be further moved to observe the details in real-time two-dimensional images.

Further, in the case where the three-dimensional image is partially insufficient or unclear, if the organ does not move, it is possible to add a scan to the three-dimensional image once created. Press FS2 to freeze the 3D image. When the three-dimensional image is observed and is insufficient, the ultrasonic probe is moved to a position at which the ultrasonic probe is to be replenished while observing the real-time two-dimensional image and the frozen three-dimensional image. Then, when FS3 is pressed, the subsequent scanned images are added to the three-dimensional image, and the three-dimensional image can be displayed in real time. When the additional three-dimensional scan is completed, FS1 or FS2 is pressed to freeze the three-dimensional image.

When the FS2 is pressed, the plane currently being scanned on the three-dimensional image, that is, the surface of the two-dimensional image may be displayed on the three-dimensional image with a marker or the like. Good.

When FS1 is pressed, both the two-dimensional image and the three-dimensional image are frozen. In this case, as in the conventional ultrasonic diagnostic apparatus, a fixed number of two-dimensional images temporally before the freeze point, for example, 64 are stored. Any of these images can be displayed by operating the image selection switch. Therefore, 3
While observing the two-dimensional image, it is also possible to observe the already scanned two-dimensional image. In that case, the surface of the currently displayed two-dimensional image may be displayed on the three-dimensional image using a marker or the like.

Although a three-dimensional image is created using all the scanned two-dimensional images, a three-dimensional image may be created using only a two-dimensional image synchronized with a specific signal of an electrocardiogram. Good. In this case, while observing a real-time three-dimensional image, the moving speed of the probe is adjusted and
Perform a dimensional scan. In this way, even a fast-moving organ such as the heart can observe a three-dimensional image in real time.

When a three-dimensional image is created from a two-dimensional image, if the same address is present in the three-dimensional memory space (when the scan planes partially overlap), the one with the larger voxel value is selected. I have to. This is to prevent Doppler disappearance due to heart beats and the like. Therefore, if the probe is moved slowly to perform a three-dimensional scan, the same surface is scanned a plurality of times, so that Doppler disappearance can be prevented. However, once a large voxel value is entered, it may not disappear due to the half-sided noise, artifact, movement of the organ, and the like. For this reason, if the three-dimensional scan is performed for a long time, there is a problem in that artifacts increase in the three-dimensional image. Therefore, a recursive filter is applied to the voxel values of the three-dimensional memory corresponding to the scan plane,
Old information may be sequentially deleted. The recursive filter is, for example, as shown in Table 1. Table 1
FIG. 9 shows a relationship when a current voxel value of a three-dimensional memory is updated with data of a scanned image. To do this, the volume memory 8A allows each voxel to store a two digit number. Further, the output from the memory outputs a value as shown in Table 2 below. In the three-dimensional memory, it is assumed that all zeros are stored in the initial state. Tables 1 and 2 are examples, and various modifications are possible without being limited to them.

[0050]

[Table 1]

[0051]

[Table 2]

In the embodiment described above, three-dimensional display is performed by a TV monitor. Next, an embodiment in which a three-dimensional display method is different will be described. FIG. 8 shows a part of the configuration of this embodiment. FIG. 8 shows 3D-D of the configuration of the embodiment shown in FIG.
The SC 8 and the three-dimensional display system 10 are respectively connected to the 3D display control unit 8
0 and 3D display device 90. Therefore, portions not shown in FIG. 8 are the same as those in FIG. 8 and FIG. 1, the same components are denoted by the same reference numerals.

FIG. 9 shows an example of the configuration of the three-dimensional display control section 80. Until a voxel value is created in the volume memory 8A, it is the same as the above-described embodiment. A rotation angle indicating a display direction, a moving amount for moving the center of the display, and an enlargement / reduction ratio for determining a display size are input to the three-dimensional address controller 84 from an operation panel (not shown). 3D address controller 8
4 calculates the relationship between the three-dimensional coordinates of the display and the coordinates of the three-dimensional image created in the volume memory 8A from these data. This calculation can be obtained by a simple affine transformation. The three-dimensional address controller 84 obtains an address of the volume memory 8A corresponding to each point on the three-dimensional display, reads out the voxel value, and stores it in the three-dimensional display memory 82.

Next, the 3D display device 90 will be described with reference to the conceptual diagram shown in FIG. The LEDs 101 are arranged in, for example, a 128 × 128 matrix to represent the X and Y planes. The LED 101 may be a single color or a plurality of colors. The entire matrix is moved in the Z direction, for example, 1
Reciprocate at 0 times / sec. Then, the position of one LED at a certain time point exists at one point on three dimensions. Each point on the three-dimension corresponds twice in one round trip, but usually only the forward path is used and the return path is not used. Therefore, 1
There are three-dimensional points every 0 times / sec. By blinking the LED corresponding to the voxel value of the three-dimensional image,
A dimensional image can be displayed. As for one point, the light is turned on only every 10 times / sec. However, since a human eye has an afterimage effect, it looks like a continuous three-dimensional image.

The three-dimensional display device 90 reads the voxel value of the three-dimensional display memory 82 corresponding to the current three-dimensional coordinates of the LED and blinks the LED. At this time, a display method is instructed from an operation panel (not shown), and the display is performed in a display method based on the display method. As the display method, for example, as shown in Table 3, the voxel value and the blinking of the LED are displayed in correspondence.

[0056]

[Table 3] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible as long as the gist described in the claims is not changed.

[0057]

As described in detail above, according to the first aspect of the present invention, since the two-dimensional images obtained by projecting the three-dimensional distribution data from a plurality of directions are successively displayed in sequence, the state of the entire blood flow can be three-dimensionally displayed. In addition, it is possible to partially update the data of the missing part or the unclear part in the frozen three-dimensional distribution data as necessary. According to the second aspect of the present invention, the state of the entire blood flow can be three-dimensionally recognized by sequentially displaying two-dimensional images obtained by projecting three-dimensional distribution data from a plurality of directions. And a two-dimensional image obtained from the movement information, it is possible to perform a detailed observation on a part that is difficult to observe in detail with three-dimensional distribution data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus according to a first embodiment.

FIG. 2 is a block diagram showing a schematic configuration of the three-dimensional digital scan converter shown in FIG.

FIG. 3 is a diagram showing an example of a three-dimensional scan.

FIG. 4 is a diagram illustrating an operation of generating volume data.

FIG. 5 is an external view of a three-dimensional position detection arm.

FIG. 6 is a view for explaining an operation of obtaining a projection image from the volume data shown in FIG. 4;

FIG. 7 is an exemplary view for explaining three-dimensional display of blood flow by a plurality of projection images obtained by repeating the operation shown in FIG. 6;

FIG. 8 is a block diagram showing a part of the configuration of an embodiment having a different three-dimensional display method.

FIG. 9 is a block diagram showing a configuration of a three-dimensional display unit 80.

FIG. 10 is a conceptual diagram of a three-dimensional display device 90.

[Explanation of symbols]

 Reference Signs List 1 position detection circuit 2 ultrasonic probe 3 transmission system 4 reception system 5 B-mode processing system 6 color flow mapping processing system 7 digital scan converter 8 3D digital scan converter 9 2D display system 10 3D display system 12 Operation switch 13 system controller

Continuation of the front page (56) References JP-A-61-128948 (JP, A) JP-A-2-36851 (JP, A) JP-A-4-174655 (JP, A) Takeshi Sato, Hiroshi Sasaki, Yoichi Sumino , Hongo Nobuhiro, Doji Masayoshi. "3D colored Doppler". April 25, 1992. Proceedings of the 60th Annual Meeting of the Japanese Society of Sonographers. Published by The Japan Society of Sonographers. Pp. 137-138 (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 8/00-8/15

Claims (3)

(57) [Claims] 1. An ultrasonic probe for transmitting an ultrasonic wave into a subject and receiving an echo signal from the subject, and means for obtaining movement information of a moving body in the subject based on the echo signal. Means for detecting at least one of the position or the direction of the ultrasonic probe, and obtaining position information of the moving body in a three-dimensional space based on the detection result, based on the movement information and the position information, A memory for storing three-dimensional distribution data of movement information; an operation unit for performing operations related to holding and updating of images; a state for holding three-dimensional distribution data stored in the memory; Means for switching the three-dimensional distribution data to be partially updated based on the movement information and the position information in accordance with an input to the operation means; An ultrasonic diagnostic apparatus, comprising: three-dimensional image display means for obtaining two-dimensional images projected from several directions in real time from three-dimensional distribution data stored in the memory and sequentially displaying the three-dimensional images sequentially. Means for scanning the inside of the subject with ultrasonic waves to obtain an echo signal, means for obtaining data for a B-mode image based on the echo signal, and means for obtaining data for a B-mode image based on the echo signal. Means for obtaining movement information of a moving object; operation means for performing operations relating to holding and updating of an image; means for displaying a two-dimensional tomographic image obtained based on the data for the B-mode image and the movement information A memory storing three-dimensional distribution data of the movement information based on the movement information; and a two-dimensional image projected from a plurality of directions shifted by a predetermined angle from the three-dimensional distribution data of the movement information stored in the memory. A three-dimensional image display means for sequentially displaying the two-dimensional tomographic images and sequentially updating the two-dimensional tomographic images and the three-dimensional distribution data, and updating the two-dimensional tomographic images in real time. Ultrasonic diagnostic apparatus to and the three-dimensional distribution data and state held without updating, characterized by comprising a means for switching in response to an input to the operating means. 3. The ultrasonic diagnostic apparatus according to claim 1, wherein three-dimensional distribution data is generated using an echo signal synchronized with a specific signal of an electrocardiogram.