JP2000237191A - Cfm image display method and ultrasonic diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the sense of incompatibility caused by the change in a display color in a region where a turnover phenomenon occurs. SOLUTION: In an ultrasonic diagnostic device 200, a CFM process section 14a calculates a blood flow velocity V and the variance σ of the blood flow velocity V. A differential calculation section 4a outputs the function value f(ΔV, σ) including the difference ΔV between the blood flow velocity V corresponding to the latest frame and the blood flow velocity Vτstored in a frame memory 3 and the variance σ. A DSC 5a generates the CFM image data for displaying a CFM image in the same display color at least in a large-velocity region or in a display color giving little sense of incompatibility even if a region with a different flow direction is adjacently displayed for a flow region with a large function value f(ΔV, σ), thereby an offensive display is eliminated, and an obvious screen is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CFM image display method and an ultrasonic diagnostic apparatus, and more particularly, to a CFM image capable of reducing discomfort caused by a change in display color in an area where aliasing occurs. The present invention relates to a display method and an ultrasonic diagnostic apparatus. In particular, high-speed blood flow
Useful to display.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of a conventional ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus 500 includes an ultrasonic probe 11 and a beam former (Beam Former) 12.
, B-mode processing unit 13 and CFM (Color Flow Mappi
ng) Processing unit 14 and DSC (Digital Scan Converter)
55 and a CRT (Cathode Ray Tube) 16. The ultrasonic probe 11 and the beam former 12 collect ultrasonic echo signals from a plurality of sampling points distributed in the internal space of the subject. The B-mode processing unit 13 acquires ultrasonic echo signal data at a number of two-dimensionally distributed sampling points, performs processing such as envelope detection and logarithmic compression, and generates B-mode data. The CFM processing unit 14 obtains data of Doppler frequency at a number of sampling points distributed two-dimensionally, calculates and outputs a blood flow velocity V. The DSC 55
Converts the blood flow velocity V into display values (display color and luminance), performs two-dimensional mapping according to the position of each sampling point, and generates CFM image data. The CRT 16
Displays a CFM image on a screen based on the CFM image data.

FIG. 8 is a schematic diagram of a color bar B51 showing a relationship between a blood flow direction, a blood flow velocity (absolute value), and a display color in a CFM image. The blood flow in the direction approaching the ultrasonic probe 11 is displayed in “red”. The blood flow in the direction away from the ultrasonic probe 11 is displayed in “blue”. Said "red" or "blue"
Are displayed brighter as the blood flow velocity V is higher (faster blood flow), and darker as the blood flow velocity V is lower (slower blood flow).

FIG. 9 shows a state in which the ultrasonic probe 11 is
FIG. 4 is an explanatory diagram showing a state in which a blood flow flowing through a blood vessel T is photographed by applying a photograph. In the figure, the turbulence regions A1 and A2 are regions where the blood flow velocity V temporarily becomes extremely large and the Doppler frequency may exceed １ ／ of the repetition frequency.
FIG. 10 is a schematic diagram of the CFM image G51 displayed on the screen of the CRT 16 by the photographing of FIG. Most of the blood flow region approaching the ultrasonic probe 11 is displayed as a “bright red” region r. However, in the turbulent flow regions A1 and A2, a folding phenomenon occurs.
Apparently, the flow direction is reversed and displayed as "bright blue" areas b1 and b2.

[0005]

In the above-described conventional ultrasonic diagnostic apparatus 500, when a very high-speed blood flow is generated, the blood flow returns to the "bright red" (or "bright blue") region r due to the folding phenomenon. , And “bright blue” (or “bright red”) areas b1 and b2 are displayed together (FIG. 9, FIG.
Therefore, there is a problem that the interpreter (doctor or technician) can easily feel a strong sense of discomfort. That is, the boundary area between “bright red” and “bright blue” is apparently “bright white” and gives an unpleasant impression, and the degree of fatigue when reading CFM images of many patients increases. Causes inconvenience. Therefore, an object of the present invention is to provide a CFM image display method and an ultrasonic diagnostic apparatus that can reduce a sense of discomfort caused by a change in display color in a region where a folding phenomenon occurs.

[0006]

According to a first aspect of the present invention, an ultrasonic wave is transmitted into an object, an ultrasonic echo signal from a fluid flowing through the object is collected, and a two-dimensional distribution is obtained. A CFM image that obtains Doppler frequency data at a number of sampling points, calculates the flow direction and velocity of the fluid based on the data, and displays a CFM image that reflects the flow direction and velocity on the display color and brightness. In a display method, for a flow region in which at least one of the speed difference and the flow variance corresponding to different time phases is large, at least the region with a large speed has the same display color regardless of the flow direction or is different. Provided is a CFM image display method, characterized in that a display color is displayed with less discomfort even when regions in the flow direction are displayed adjacent to each other. The inventor of the present invention has conducted intensive studies and found that the state where the Doppler frequency exceeds 1/2 of the repetition frequency is likely to occur in a region where the difference between the velocities of the fluid and the dispersion of the flow are large, that is, the aliasing phenomenon. Was found to be highly likely to occur. Therefore, in the CFM image display method according to the first aspect, for a flow region in which at least one of the difference between the velocities of the fluid and the variance of the flow is large, at least the region with the large velocity has the same display color regardless of the flow direction. Alternatively, the display color is set to a display color with less discomfort even when regions in different flow directions are displayed adjacently. As a result, discomfort caused by a change in display color in an area where the aliasing phenomenon occurs can be sufficiently reduced, and an easy-to-view CFM image can be displayed.

In a second aspect, the present invention is directed to a method for transmitting ultrasonic waves into an object to collect ultrasonic echo signals from a fluid flowing through the object, and to obtain Doppler signals at a number of two-dimensionally distributed sampling points. Obtain frequency data, calculate the flow direction and velocity of the fluid based on the data,
A CFM image display method for displaying a CFM image in which the flow direction and the speed are reflected in a display color and brightness,
In a flow region in which a return phenomenon is highly likely to occur, the display color does not change even if the return phenomenon occurs or is displayed in a display color with little change.
An M image display method is provided. CF according to the second aspect
In the M-image display method, the flow area where the aliasing phenomenon is likely to occur is displayed with no change in the display color even if the aliasing phenomenon occurs or in a display color with little change. It is possible to prevent the change of the display color from becoming extremely large, and to sufficiently reduce the sense of discomfort.

[0008] In a third aspect, the present invention provides an ultrasonic probe which transmits an ultrasonic wave into an object from an ultrasonic probe, collects ultrasonic echo signals from a blood flow in the object, and performs two-dimensional distribution. A CFM image in which Doppler frequency data at a number of sampling points is obtained, the flow direction and the blood flow velocity of the blood flow are calculated based on the data, and the flow direction and the blood flow velocity are reflected on the display color and brightness. An ultrasonic diagnostic apparatus having a function of displaying at least one of a difference between the blood flow velocities corresponding to different time phases and a variance of the flow, wherein the difference or the variance is Regarding a large blood flow region, at least a region with a large velocity has the same display color regardless of the flow direction, or a display color with little discomfort even when regions with different flow directions are displayed adjacently. To provide an ultrasonic diagnostic apparatus characterized by comprising a 示色 determining means. The ultrasonic diagnostic apparatus according to the third aspect includes the CFM according to the first aspect.
Implementing an image display method to convert blood flow in a subject into CFM
Since the image is displayed as an image, it is possible to sufficiently reduce a sense of incongruity caused by a change in the display color in the blood flow region where the aliasing phenomenon occurs, and to display an easy-to-view CFM image. For this reason,
It is possible to reduce the degree of fatigue of the radiologist who interprets the CFM image and improve the diagnosis efficiency.

In a fourth aspect, the present invention provides an ultrasonic probe which transmits an ultrasonic wave into an object from an ultrasonic probe, collects ultrasonic echo signals from a blood flow in the object, and performs two-dimensional distribution. A CFM image in which Doppler frequency data at a number of sampling points is obtained, the flow direction and the blood flow velocity of the blood flow are calculated based on the data, and the flow direction and the blood flow velocity are reflected on the display color and brightness. Ultrasound diagnostic apparatus having a function of displaying, in a blood flow region that is highly likely to cause a return phenomenon, the display color does not change even if the return phenomenon occurs or is displayed in a display color with little change The present invention provides an ultrasonic diagnostic apparatus comprising a display color change suppressing means. Since the ultrasonic diagnostic apparatus according to the fourth aspect performs the CFM image display method according to the second aspect and displays a blood flow flowing through the subject in a CFM image, the ultrasonic diagnostic apparatus can be used in a blood flow region where a return phenomenon occurs. Can be prevented from becoming extremely large, and the sense of incongruity felt by the interpreter can be sufficiently reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments of the invention shown in the drawings. Note that the present invention is not limited by this. First Embodiment FIG. 1 is a configuration diagram illustrating an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. This ultrasonic diagnostic apparatus 100
Is configured to include an ultrasonic probe 11, a beam former 12, a B-mode processing unit 13, a CFM processing unit 14, a frame memory 3, a difference calculation unit 4, a DSC 5, and a CRT 16. ing. The ultrasonic probe 11 and the beam former 12 collect ultrasonic echo signals from a plurality of sampling points distributed in the internal space of the subject.
The B-mode processing unit 13 acquires ultrasonic echo signal data at a number of two-dimensionally distributed sampling points, performs processing such as envelope detection and logarithmic compression to generate B-mode data. The CFM processing unit 14 obtains data of Doppler frequency at a number of sampling points distributed two-dimensionally, calculates and outputs a blood flow velocity V. That is, the speed calculation unit 1 uses the autocorrelation method or the like to perform CFM.
An operation for calculating the value is performed, and the post-processing unit 2 performs a filtering process such as frame averaging. The frame memory 3 stores the blood flow velocity V for one frame. The difference calculation unit 4 includes:
The blood flow velocity V corresponding to the latest frame and the blood flow velocity V stored in the frame memory 3 one time earlier.
The difference ΔV from τ is calculated and output. The difference may be a simple subtraction or a function including a subtraction (however, since the sign of the blood flow velocity V and the sign of vτ may be different, the difference is calculated as an absolute value). The DSC 5 comprises:
The blood flow velocity V is converted into a display value (display color and luminance) for an area where the B-mode data is equal to or less than a predetermined value, and two-dimensional mapping is performed in accordance with the position of each sampling point to generate CFM image data. However, the display color of the CFM image is
It is determined depending on both the blood flow velocity V and the difference ΔV (described in detail later with reference to the two-dimensional color bar B1 in FIG. 2). The CRT 16 displays a CFM image on a screen based on the CFM image data.

FIG. 2 is a schematic diagram of a two-dimensional color bar B1 showing a relationship between a blood flow direction, a blood flow velocity V (magnitude of absolute value), and a display color in a CFM image. The blood flow in the direction approaching the ultrasonic probe 11 is displayed in “red”. The blood flow in the direction away from the ultrasonic probe 11 is displayed in “blue”. Said "red" or "blue"
Are displayed brighter as the blood flow velocity V is higher (faster blood flow), and darker as the blood flow velocity V is lower (slower blood flow). However, as the difference ΔV is larger, “yellow” is more strongly mixed, and when the difference ΔV is largest, the fastest blood flow in the direction approaching the ultrasonic probe 11 is displayed in “orange”, The fastest blood flow in the direction away from the ultrasonic probe 11 is displayed in “yellow green”. Note that the color mixing of “yellow” may be performed only for the difference ΔV equal to or larger than the predetermined threshold, or for the difference ΔV
You may go to. Therefore, in the chromaticity diagram C shown in FIG. 3, when the difference ΔV is small, the display color changes in the direction of the dashed line arrow S with respect to the change in the blood flow velocity V. On the other hand, when the difference ΔV is large,
In response to a change in the blood flow velocity V, the display color changes in the direction of the dotted arrow SΔ within the range of similar colors including “yellow” (range from orange to yellowish green). Can be prevented from becoming extremely large. That is, it is possible to prevent "bright white" from being observed and becoming annoying. The two-dimensional color bar B1 is CF
It may be displayed for reference on the screen displaying the M image,
It does not need to be displayed. When displaying the two-dimensional color bar B1, it is easy for a radiologist (doctor or technician) to grasp the blood flow velocity V and the difference ΔV corresponding to the display color. When a color bar similar to the conventional color bar B51 shown in FIG. 8 is displayed without displaying the two-dimensional color bar B1,
It is possible to avoid the inconvenience that an image reader is confused with a color bar in the conventional speed dispersion display.

FIG. 4 shows that the ultrasonic probe 11 is
FIG. 2 is an explanatory diagram showing a state in which a blood flow flowing through a blood vessel T is imaged by applying (see FIG. 1). In the figure, turbulent regions A1, A2
Is a region where the blood flow velocity V temporarily becomes very large and the Doppler frequency may exceed 繰 り 返 し of the repetition frequency. FIG. 5 shows a CRT by the photographing of FIG.
It is a schematic diagram of CFM image G1 displayed on the screen of No. 16. Most of the blood flow region approaching the ultrasonic probe 11 is displayed as a “bright red” region r. In the turbulent flow regions A1 and A2, a folding phenomenon occurs. However, since the difference ΔV is large, the “yellow-green” regions yb1 and yb
It is displayed as b2, and the feeling of discomfort with “bright red” is reduced as compared with “bright blue”.

According to the ultrasonic diagnostic apparatus 100 described above, in a region where the difference ΔV in the blood flow velocity V between frames is large (a region where the probability of occurrence of the aliasing phenomenon is high), the similar color to the blood flow velocity V is used. The display color of the CFM image G1 is determined by the two-dimensional color bar B1 (see FIG. 2) that changes the color within the range of. Therefore, even when the turbulence regions A1 and A2 where the aliasing phenomenon occurs are displayed adjacent to other regions (red or blue regions), it is possible to sufficiently reduce the sense of discomfort experienced by the reader.

In the two-dimensional color bar B1 according to the first embodiment, the display color is changed within the range of similar colors when the difference ΔV is large. May be displayed in the same display color (for example, “yellow”).

Second Embodiment FIG. 6 is a configuration diagram showing an ultrasonic diagnostic apparatus according to a second embodiment of the present invention. In the ultrasonic diagnostic apparatus 200, the CFM processing unit 14a (the speed calculation unit 1, the post-processing unit 2)
a) is the variance σ of the blood flow velocity V in addition to the blood flow velocity V
Is calculated.

The difference calculation unit 4a calculates a difference ΔV between the blood flow velocity V corresponding to the latest frame and the blood flow velocity Vτ stored in the frame memory 3, and a function value f (ΔV,
σ) is output. A specific example of the function value f (ΔV, σ) is as follows. (1) f (ΔV, σ) = MAX (ΔV, σ) where MAX is a function that adopts the larger one of the two values. (2) f (ΔV, σ) = ｛ΔV · σ｝ / ｛ΔV _full · σ
_full ｝ where ΔV _full and σ _full are values corresponding to the full scale of ΔV and σ, respectively.

The DSC 5a converts the blood flow velocity V into a display value (display color and luminance), performs two-dimensional mapping according to the position of each sampling point, and generates CFM image data. However, the display color is the blood flow velocity V and the function value f
(ΔV, σ) (the difference ΔV in the two-dimensional color bar B1 in FIG.
The display color is determined by the two-dimensional color bar replaced with σ)).

According to the ultrasonic diagnostic apparatus 200 described above, the display color is determined by reflecting the variance σ in addition to the difference ΔV of the blood flow velocity V between frames, so that the region where the aliasing phenomenon is more likely to occur is further increased. It can be determined appropriately.

[0019]

According to the CFM image display method and the ultrasonic diagnostic apparatus of the present invention, in the flow region where the return phenomenon is highly likely to occur, the display color does not change or does not change even if the return phenomenon occurs. Since the display is performed with the display color with less color, it is possible to sufficiently reduce the sense of discomfort when viewing the CFM image. In particular, a flow region in which a difference in blood flow velocity between a plurality of time phases or a variance of a blood flow is large is regarded as a flow region in which a return phenomenon is highly likely to occur. It is possible to provide a diagnostic image that gives a natural impression by sufficiently reducing the display drop between the flow region and the boundary region, and has high clinical utility.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an ultrasonic diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a two-dimensional color bar in the ultrasonic diagnostic apparatus of FIG.

FIG. 3 is a chromaticity diagram showing a change in display color in the ultrasonic diagnostic apparatus of FIG. 1;

FIG. 4 is an explanatory diagram showing a state in which a blood flow flowing through a blood vessel in a subject is imaged.

FIG. 5 is a CFM displayed by the ultrasonic diagnostic apparatus of FIG.
It is an illustration figure showing an image.

FIG. 6 is a configuration diagram showing an ultrasonic diagnostic apparatus according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram illustrating an example of a conventional ultrasonic diagnostic apparatus.

FIG. 8 is a schematic diagram showing a color bar in the ultrasonic diagnostic apparatus of FIG. 7;

FIG. 9 is an explanatory diagram showing a state in which a blood flow flowing through a blood vessel in a subject is imaged.

10 is a CF displayed by the ultrasonic diagnostic apparatus of FIG.
FIG. 4 is an explanatory diagram showing an M image.

[Explanation of symbols]

 Reference Signs List 100, 200 Ultrasound diagnostic apparatus 1 Speed calculation unit 2, 2a Post-processing unit 3 Frame memory 4, 4a Difference calculation unit 5, 5a DSC 11 Ultrasonic probe 12 Beam former 13 B-mode processing unit 14, 14a CFM processing unit 16 CRT B1 Two-dimensional color bar H Subject V Blood flow velocity ΔV Difference σ Dispersion

Claims (4)

[Claims] 1. An ultrasonic wave is transmitted into an object, an ultrasonic echo signal from a fluid flowing through the object is collected, and data of Doppler frequency at a number of two-dimensionally distributed sampling points is obtained. Calculating a flow direction and velocity of the fluid based on the data, and displaying a CFM image in which the flow direction and velocity are reflected in a display color and luminance;
An FM image display method, wherein, for a flow region in which at least one of the difference between the velocities corresponding to different time phases and the variance of the flow is large, whether at least the region with a large velocity has the same display color regardless of the flow direction. Alternatively, a CFM image display method characterized in that a display color that causes less discomfort even when regions in different flow directions are displayed adjacently. 2. An ultrasonic wave is transmitted into an object, an ultrasonic echo signal from a fluid flowing through the object is collected, and data of Doppler frequency at a number of two-dimensionally distributed sampling points is obtained. Calculating a flow direction and velocity of the fluid based on the data, and displaying a CFM image in which the flow direction and velocity are reflected in a display color and luminance;
A method for displaying an FM image, comprising: displaying, in a flow region having a high probability of occurrence of a folding phenomenon, a display color having no or little change in display color even when the folding phenomenon occurs.
M image display method. 3. An ultrasonic probe transmits ultrasonic waves into a subject, collects ultrasonic echo signals from a blood flow in the subject, and obtains Doppler frequencies at a number of two-dimensionally distributed sampling points. CF that obtains data, calculates a flow direction and a blood flow velocity of the blood flow based on the data, and reflects the flow direction and the blood flow velocity on a display color and luminance.
An ultrasonic diagnostic apparatus having a function of displaying an M image, comprising: a difference / dispersion detecting unit configured to detect at least one of a difference between the blood flow velocities corresponding to different time phases and a variance of the flow; A display color determining unit that sets a display color of a blood flow region having a large variance to have the same display color regardless of a flow direction at least in a region having a high velocity, or to provide a display color with less discomfort even when regions in different flow directions are displayed adjacent to each other. An ultrasonic diagnostic apparatus comprising: 4. An ultrasonic probe transmits ultrasonic waves into a subject, collects ultrasonic echo signals from a blood flow in the subject, and obtains Doppler frequencies at a number of two-dimensionally distributed sampling points. CF that obtains data, calculates a flow direction and a blood flow velocity of the blood flow based on the data, and reflects the flow direction and the blood flow velocity on a display color and luminance.
An ultrasonic diagnostic apparatus having a function of displaying an M image, wherein, for a blood flow region having a high probability of occurrence of a folding phenomenon, a display color does not change or a display color with little change even when the folding phenomenon occurs. An ultrasonic diagnostic apparatus, comprising: a display color change suppressing unit for displaying in (1).