JP3776563B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that displays an image of motion information of a moving body (for example, blood flow) in a living body.
[0002]
[Prior art]
Ultrasound diagnostic apparatuses that display in-vivo tomographic images and blood flow images are used in the medical field. Various apparatuses have been put to practical use as ultrasonic diagnostic apparatuses. In recent years, there is also an apparatus that can implement ultrasonic diagnosis in a blood vessel by inserting a catheter-like ultrasonic probe into the blood vessel. Such an apparatus displays a two-dimensional tomographic image of blood vessels and a two-dimensional Doppler image of blood flow.
[0003]
The Doppler information is extracted by measuring the Doppler shift included in the echoes from the moving body in the living body. By analyzing the Doppler information, the velocity (instantaneous average velocity), power, and variance value (velocity of the blood flow) are analyzed. Movement information such as (dispersion value) is acquired. Here, the conventional two-dimensional Doppler image is obtained by assigning, for example, red and blue for each movement direction of the blood flow, and expressing the speed in each direction by color intensity. In this case, the magnitude of the velocity dispersion value is expressed by mixing other hues as necessary. In the conventional apparatus, the power is generally displayed as a power spectrum (a speed distribution in which the power component of each speed is represented by luminance).
[0004]
As is well known, the measured blood flow velocity corresponds to a component along the ultrasonic beam in the actual blood flow velocity (velocity vector). Therefore, if the angle between each ultrasonic beam and the blood flow is different, the speed measured on each ultrasonic beam is different.
[0005]
[Problems to be solved by the invention]
When imaging blood flow motion information using the catheter-like ultrasonic probe as described above, conventionally, the speed of each measurement point (sample point) is displayed as a two-dimensional Doppler image. .
[0006]
However, the speed display also displays the direction of blood flow, so depending on the running state of the blood vessel, for example, even though it is a blood flow flowing in the forward direction, it is expressed as a partial backflow. There was a case where it was done. For this reason, there was a problem that it was annoying at the time of diagnosis and there was a sense of incongruity.
[0007]
Therefore, it is conceivable to adopt a two-dimensional display of only the power independent of the flow direction or a two-dimensional display of only the absolute value of the velocity, but in that case, due to adhesion with other blood vessels, When blood regurgitation actually occurs, there is a problem that it cannot be expressed as an image.
[0008]
The present invention has been made in view of the above-described conventional problems. The purpose of the present invention is to display an image similar to a forward flow for an apparent reverse flow when displaying a two-dimensional Doppler image. The purpose of this is to make it possible to express an image of the backflow when the backflow occurs.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an ultrasonic diagnostic apparatus that processes Doppler information included in a received signal obtained by transmission / reception of ultrasonic waves and displays an ultrasonic image based on the Doppler information. A turbulent flow determining means for determining the presence or absence of turbulent flow for each sample point, and a first image display is selected for the sample points for which the turbulent flow is not determined in displaying motion information for each sample point, The sample point for which the flow is determined includes selection means for selecting a second image display different from the first image display.
[0010]
According to the above configuration, an appropriate display format is selected for each sample point (or each pixel), that is, the first image display is selected if it is not turbulent flow, and the first display is selected if it is turbulent flow (mainly reverse flow). 2 image display is selected. Since the velocity distribution is widened in turbulent flow, it is desirable to use the velocity dispersion value for turbulent flow determination.
[0011]
Therefore, according to the present invention, it is possible to solve the apparent backflow problem pointed out in the conventional two-dimensional velocity display, and to clearly express the turbulent flow when turbulent flow actually occurs. .
[0012]
In a preferred aspect of the present invention, the first image display is colored regardless of the flow direction, and the second image display is colored depending on the flow direction.
[0013]
According to the above configuration, when a turbulent flow occurs, it is possible to express what the state is. For example, when the flow direction as a whole is defined as the main direction, the flow direction and intensity at each sample point in turbulent flow can be expressed by hue (for example, hue, luminance, saturation, etc.).
[0014]
In order to achieve the above object, the present invention provides an ultrasonic diagnostic apparatus for processing Doppler information included in a reception signal obtained by transmission / reception of ultrasonic waves to display an ultrasonic image. A power calculation means for calculating power based on the speed, a speed calculation means for calculating speed based on the Doppler information, a dispersion calculation means for calculating a dispersion value based on the Doppler information, and for each sample point And selecting means for selecting image display of the power or image display of the speed according to the magnitude of the variance value.
[0015]
According to the above configuration, power image display or speed image display is selected for each sample point in accordance with the magnitude of the variance value. In power image display, the direction of flow is ignored, so the problem of apparent backflow is eliminated. In the velocity image display, since the flow direction is also expressed, the generation of the turbulent flow and the direction of the turbulent flow can be expressed. Therefore, useful image information can be provided for disease diagnosis.
[0016]
In displaying the speed image, the absolute value of the speed may be displayed. In this case, it is desirable to set a display form different from the power image display.
[0017]
In a preferred aspect of the present invention, the selecting means selects an image display of the power for a normal sample point where the variance value is smaller than a predetermined value, and for the turbulent sample point where the variance value is larger than a predetermined value. The speed image display is selected.
[0018]
In a preferred aspect of the present invention, different colors are used for the power image display and the speed image display. If the colors in each image display are different, the backflow can be clearly expressed.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
[0020]
FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall configuration of the ultrasonic diagnostic apparatus.
[0021]
The ultrasonic probe 10 is a catheter-like ultrasonic probe inserted into a blood vessel in the present embodiment, which will be described in detail later with reference to FIG. Ultrasonic waves are transmitted in the blood vessel by the ultrasonic probe 10, and echoes reflected by the blood flow as a moving body are received by the ultrasonic probe 10.
[0022]
The transmission / reception unit 12 is a circuit that supplies a transmission signal to the ultrasonic probe 10 and performs processing such as amplification on the reception signal from the ultrasonic probe 10.
[0023]
The reception signal output from the transmission / reception unit 12 is input to the Doppler information calculation unit 14. The Doppler information calculation unit 14 is a circuit that extracts Doppler information, that is, motion information, in the received signal by calculation, and includes, for example, a circuit that performs autocorrelation calculation. Although not shown in FIG. 1, a circuit for forming a two-dimensional tomographic image based on the reception signal output from the transmission / reception unit 12 may be provided. Then, the two-dimensional tomographic image may be combined with a two-dimensional Doppler image described later and displayed on the display 32.
[0024]
The Doppler information output from the Doppler information calculation unit 14 is input to the variance value calculation unit 16, the power calculation unit 18, and the speed calculation unit 20. Here, the variance value calculation unit 16 is a circuit that calculates a variance value related to the spread of speed based on the Doppler information output from the Doppler information calculation unit 14. The power calculation unit 18 is a circuit that calculates power based on the Doppler information output from the Doppler information calculation unit 14. The velocity calculation unit 20 is a circuit that calculates a blood flow velocity (average velocity) based on the Doppler information output from the Doppler information calculation unit 14. These arithmetic units 16, 18, and 20 are circuits known per se.
[0025]
The power image processing unit 22 is a circuit for forming a power image with respect to the power output from the power calculation unit 18. Specifically, as described later, the brightness of a predetermined color is adjusted in accordance with the magnitude of the power. Has been decided. The speed image processing unit 24 forms a speed image according to the speed output from the speed calculation unit 20, and specifically, brightness of a predetermined color for each of the positive direction and the negative direction of the speed. Is determined. Then, the power image output from the power image processing unit 22 and the speed image output from the speed image processing unit 24 are input to the signal switcher 30, and as will be described below, for each sample point (pixel), The image display, that is, the display format is selected.
[0026]
Note that the variance value from the variance value calculation unit 16 is also input to the velocity image processing unit 24, and image processing that reflects the variance value is performed when the velocity image is formed. Specifically, image processing is performed in which colors that are not used for coloring of power and speed are mixed according to the dispersion value.
[0027]
The display format selection unit 26 controls the operation of the signal switch 30 based on the variance value for each sample point. Specifically, when the variance value is smaller than the reference value stored in the reference value memory 28, a power image is selected for the sample point, while when the variance value is larger than the reference value, the power value is selected. A velocity image is selected for the sample point. Therefore, one display format is selected for each sample point, in other words, for each pixel. In this case, an image is displayed with a display format using a power image for a blood flowing normally, and an image is displayed with a velocity image for a turbulent flow such as a backflow. Therefore, by seeing the Doppler image constructed by such two types of image formats, as described above, the backflow that is actually generated can be clarified without being affected by an unsightly apparent backflow. Can be recognized. The coloring method in the power image processing unit 22 and the speed image processing unit 24 will be described in detail later.
[0028]
FIG. 2 shows a specific example of the ultrasonic probe 10 shown in FIG. The ultrasonic probe 10 includes a catheter 40 inserted into a blood vessel 200, a rotating wire 42 that rotates within the catheter 40, and an ultrasonic transducer 44 that is provided at the tip of the rotating wire 42. In addition, it includes a drive motor for rotating a rotating wire (not shown).
[0029]
The ultrasonic transducer 44 is provided so as to be inclined at a constant angle with respect to the central axis of the rotating wire 42. For this reason, the ultrasonic beam 100 and the central axis of the rotating wire 42 intersect at a constant angle. Therefore, if the rotating wire 42 is rotated, a conical data capturing area can be formed. If the direction of the ultrasonic beam 100 is directed in a direction orthogonal to the axial direction of the rotating wire 42, there is a problem that the ultrasonic beam 100 is orthogonal to the blood flow, and Doppler information cannot be obtained. If the ultrasonic beam 100 is set in parallel with the axial direction of the rotating wire 42, there is a problem that two-dimensional data cannot be captured, and the direction of the ultrasonic beam 100 is set in consideration of the above points. ing.
[0030]
FIG. 3 shows a problem when an ultrasonic diagnosis is executed, for example, in a bent aorta by the ultrasonic probe 10 shown in FIG. As shown in FIG. 3, the blood vessel 200 is partially bent. When the ultrasonic beam is rotationally scanned in such a state, the ultrasonic beam 100A in one direction and the ultrasonic beam in a different direction are used. With 100B, velocity components having different polarities are detected even though the blood flow is the same. That is, although the blood flow is essentially approaching the ultrasonic probe 10, the blood flow is observed as if flowing in the opposite direction on the ultrasonic beam 100B. In such a state, if the speed is simply displayed in a two-dimensional manner as in the prior art, there is a problem in that a backflow that does not actually occur in a partial region in the blood vessel is expressed, which is problematic in diagnosis.
[0031]
Therefore, in the ultrasonic diagnostic apparatus according to the present embodiment, a power image is used. That is, if the power at each sample point is imaged, the power itself has no polarity, so that it is possible to effectively prevent the problem of apparent backflow. That is, for example, if red is associated with power in the state as shown in FIG. 3, it is possible to display all the blood vessels in red, and the reverse color (blue) is partially colored as in the past. The problem that occurs can be solved.
[0032]
However, if the power is always imaged for each sample point, a problem occurs in the case shown in FIG. In FIG. 4, a blood vessel 200A and a blood vessel 200B are adhered to each other at a region 210, and a blood flow from the blood vessel 200B slightly flows into the blood vessel 200A. In such a state, when the ultrasound probe 10 is inserted into the blood vessel 200A and ultrasound diagnosis is executed, and only the power image is formed for each sample point, the backflow of blood in the adhered region 210 is imaged. The problem of not being able to do arise. Therefore, in the embodiment shown in FIG. 1, the above problem is solved by switching the display format for the sample point to the speed display format when the actual backflow as shown in FIG. 4 occurs. In this case, when such a backflow occurs, the dispersion value becomes large. Therefore, the dispersion value is used as a judgment material in selecting the display format.
[0033]
That is, as shown in FIG. 1, the power display format is selected for normal sample points with a variance value smaller than the reference value, while for turbulent sample points with a variance value greater than the reference value, the velocity is selected. The image display is selected. In this way, by determining the presence or absence of turbulence, that is, backflow for each sample point, a Doppler image faithful to the actual blood flow that is not confused by the apparent backflow can be constructed, thereby diagnosing disease Accuracy can be improved.
[0034]
FIG. 5 shows coloring functions in the power image processing unit 22 and the speed image processing unit 24. In the example shown in FIG. 5, the speed image processing unit 24 executes speed coloring according to the coloring function shown in FIG. In this example, the yellow brightness is set to gradually increase in the positive speed direction, and the green brightness is set to gradually increase in the negative speed direction. Further, as shown in (B), in the power image processing unit 22, the coloring function is set so that the luminance of red gradually increases as the power increases.
[0035]
By using such a function, in the expression of normal blood flow, red can be used as a basis, and in the case where turbulent flow has occurred in a certain part of the blood vessel, the direction of flow at each sample point Accordingly, yellow or green coloring can be applied. As a result, in many cases, green dots appear densely in the red color, so that it is possible to grasp at a glance that a backflow has occurred. Moreover, even if it is a forward flow, since a very high-speed flow etc. are expressed in yellow, such a state can also be grasped | ascertained easily. Of course, in the example shown in FIG. 5, different colors are set for each of the positive and negative speed directions, but the same color, for example, blue can be set in any direction. Alternatively, the absolute value of the speed can be calculated, and a specific color such as blue can be defined for the absolute value. Furthermore, the flow of blood flow is defined as the main direction when viewed as a whole in the blood vessel, and the velocity is expressed in the same color as the power in the main direction, and the color different from the power is expressed in the direction different from the main direction. You can also In this case, a circuit or the like for determining the main direction may be provided, and a signal output from the circuit for determining the main direction may be input to the speed image processing unit 24 to control the coloring process. Various functions can be adopted for coloring.
[0036]
In the above-described embodiment, the configuration in which the ultrasonic transducer rotates is shown, but the present invention can also be applied when a non-rotating ultrasonic probe is used. In the above-described embodiment, the ultrasonic transducer is disposed in an inclined manner, but the present invention is not limited to this.
[0037]
【The invention's effect】
As described above, according to the present invention, when displaying a two-dimensional Doppler image, it is possible to clearly represent the actual backflow without being affected by the apparent backflow.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of an ultrasonic diagnostic apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a specific configuration of an ultrasonic probe.
FIG. 3 is an explanatory diagram showing a problem that an apparent backflow occurs.
FIG. 4 is a diagram showing the backflow of blood due to adhesion of blood vessels.
FIG. 5 is an explanatory diagram showing a coloring function.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Ultrasonic probe, 14 Doppler information calculation part, 16 Dispersion value calculation part, 18 Power calculation part, 20 Speed calculation part, 22 Power image processing part, 24 Speed image processing part, 26 Display format selection part, 30 Signal switching vessel.

Claims (4)

In an ultrasonic diagnostic apparatus that processes Doppler information included in a reception signal obtained by transmission / reception of ultrasonic waves and displays an ultrasonic image,
Turbulence determination means for determining the presence or absence of turbulence for each sample point based on the Doppler information;
When displaying the motion information for each sample point, the first image display is selected for the sample point for which the turbulent flow is not determined, and the sample point for which the turbulent flow is determined is different from the first image display. Selection means for selecting a second image display;
Including
The ultrasonic diagnostic apparatus, wherein the first image display is a display independent of a flow direction, and the second image display is a display depending on a flow direction . The ultrasonic diagnostic apparatus according to claim 1,
The ultrasonic diagnostic apparatus according to claim 1, wherein coloring is performed regardless of a flow direction in the first image display, and coloring depending on a flow direction is performed in the second image display. In an ultrasonic diagnostic apparatus that displays Doppler information included in a reception signal obtained by transmission / reception of ultrasonic waves and displays an ultrasonic image,
Power computing means for computing power based on the Doppler information;
Speed calculating means for calculating a speed based on the Doppler information;
Dispersion calculation means for calculating a dispersion value based on the Doppler information;
For each sample point, selection means for selecting an image display of the power or an image display of the speed according to the size of the variance value;
Only including,
The selection means selects the image display of the power for the normal sample points whose variance value is smaller than the predetermined value, and selects the image display of the velocity for the turbulent sample points whose variance value is larger than the predetermined value An ultrasonic diagnostic apparatus characterized by the above. The apparatus of claim 3.
2. The ultrasonic diagnostic apparatus according to claim 1, wherein different colors are used for the power image display and the speed image display.

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