JPH10328188A - Ultrasonic diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To image-express an actually generated back flow by judging the presence/absence of a turbulent flow at each sampling point based on doppler information so as to select first image display concerning a sample point where a turbulent flow is not judged and to select second image display concerning a sample point where a turbulent flow is judged. SOLUTION: A received signal outputted from a transmission and reception part 12 is inputted to a dappler information arithmetic part 14 to extract doppler information in the received signal by arithmetic, a distributed value arithmetic part 16 calculates a distributed value concerning the spreading of a velocity based on doppler information, a power arithmetic part 18 calculates power and a velocity arithmetic part 20 calculates the velocity of a blood flow. A display form selecting part 26 selects a power image concerning a sample point of a distributed value smaller than a reference value housed in a reference value memory 28 but selects a velocity image when the distributed value is larger. In this case, image display is executed by a displaying form by a power image concerning a normally flowing blood flow and image display is executed by the velocity image with respect to a turbulent flow such as a back flow.

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, and more particularly to an ultrasonic diagnostic apparatus for displaying motion information of a moving body (for example, blood flow) in a living body.

[0002]

2. Description of the Related Art An ultrasonic diagnostic apparatus for displaying a tomographic image or a blood flow image in a living body is used in the medical field.
Various apparatuses have been put into practical use as ultrasonic diagnostic apparatuses. In recent years, there is a device that can insert a catheter-shaped ultrasonic probe into a blood vessel and realize ultrasonic diagnosis in the blood vessel. Such a device can be used for two-dimensional tomographic images of blood vessels and two-dimensional blood flow.
A two-dimensional Doppler image is displayed.

The Doppler information is extracted by measuring a Doppler shift included in an echo from a moving body in a living body, and by analyzing the Doppler information, a velocity (an instantaneous average velocity), a power, and a variance value relating to a blood flow are obtained. Exercise information such as (variance value of speed) is acquired. Here, the conventional two-dimensional Doppler image is one in which, for example, red and blue are assigned to each direction of blood flow movement, and the speed in each direction is expressed by color density. In this case, if necessary, the magnitude of the dispersion value of the speed is expressed by mixing other hues. In the conventional device, the power is generally displayed as a power spectrum (a speed distribution in which a power component of each speed is represented by luminance) by itself.

As is well known, the measured blood flow velocity corresponds to the 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]

When imaging the blood flow motion information using the catheter-like ultrasonic probe as described above, conventionally, at each measurement point (sample) as a two-dimensional Doppler image. Point) speed was displayed.

However, since the velocity display also indicates the direction of movement of the blood flow, depending on the running state of the blood vessel, for example, a reverse flow occurs partially despite the blood flow flowing in the forward direction. Sometimes it was expressed as something. For this reason, there has been a problem that it is bothersome at the time of diagnosis and a sense of discomfort.

Therefore, it is conceivable to adopt a two-dimensional display of only the power or a two-dimensional display of only the absolute value of the speed irrespective of the direction of the flow. For this reason, when blood backflow actually occurs, there is a problem that it cannot be expressed as an image.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. An object of the present invention is to display a two-dimensional Doppler image so that an apparent reverse flow can be expressed in the same way as a forward flow. Another object of the present invention is to make it possible to express an image of the backflow when the backflow actually occurs.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an ultrasonic diagnostic system which processes Doppler information contained in a received signal obtained by transmitting and receiving ultrasonic waves to display an ultrasonic image. In the apparatus, turbulence determining means for determining the presence or absence of turbulence for each sample point based on the Doppler information, and displaying the motion information for each sample point, the sample point for which the turbulence is not determined,
And selecting means for selecting a second image display different from the first image display at the sample point where the turbulence is determined.

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, and the first image display is selected if it is turbulent (mainly countercurrent). If so, the second image display is selected. Since the velocity distribution is widened in the turbulent flow, it is desirable to use the variance value of the velocity to determine the turbulent flow.

Therefore, according to the present invention, it is possible to solve the problem of the apparent backflow pointed out in the conventional two-dimensional velocity display, and to further clarify the turbulence when it actually occurs. Can be expressed as

In a preferred aspect of the present invention, coloring is performed irrespective of the flow direction in the first image display, and coloring depending on the flow direction is performed in the second image display. I do.

According to the above configuration, when a turbulent flow is generated, it is possible to express the state of the turbulent flow. For example, when the direction of the flow as a whole is defined as the main direction, the direction and strength of the flow at each sample point in the turbulent flow are shaded (eg, hue, luminance, saturation, etc.).
Can be expressed by

According to another aspect of the present invention, there is provided an ultrasonic diagnostic apparatus which processes Doppler information included in a reception signal obtained by transmitting and receiving ultrasonic waves to display an ultrasonic image. Power calculating means for calculating power based on Doppler information; speed calculating means for calculating speed based on the Doppler information; distributed calculating means for calculating variance based on the Doppler information; Selecting means for selecting the image display of the power or the image of the speed in accordance with the magnitude of the variance value for each point.

[0015] According to the above arrangement, the power image display or the speed image display is selected for each sample point according to the magnitude of the variance value. In the image display of power, the problem of apparent backflow is eliminated because the flow direction is ignored. In the image display of the velocity, since the direction of the flow is also expressed, the generation of the turbulence and the direction of the turbulence can be expressed. Therefore, image information useful in diagnosing a disease can be provided.

In displaying the speed image, an absolute value of the speed may be displayed. In this case, it is desirable to set a display mode different from the power image display.

In a preferred aspect of the present invention, the selecting means selects the image display of the power at a normal sample point at which the variance is smaller than a predetermined value, and selects a turbulent sample point at which the variance is larger than a predetermined value. Is characterized in that the image display of the speed is selected.

In a preferred aspect of the present invention, different colors are used for the power image display and the speed image display, respectively. If the color of each image display is different, the backflow can be clearly expressed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

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.

The ultrasonic probe 10 is a catheter-like ultrasonic probe inserted into a blood vessel in the present embodiment, and will be described later in detail with reference to FIG. Ultrasonic waves are transmitted in the blood vessel by the ultrasonic probe 10, and echoes reflected by a blood flow as a moving body are received by the ultrasonic probe 10.

The transmission / reception unit 12 is a circuit that supplies a transmission signal to the ultrasonic probe 10 and executes processing such as amplification on a signal received from the ultrasonic probe 10.

The received signal output from the transmitting / receiving unit 12 is
The information 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 a received signal by calculation, and is configured by a circuit that performs, for example, an autocorrelation calculation. FIG.
Although not shown, a circuit for forming a two-dimensional tomographic image based on a 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.

The Doppler information output from the Doppler information calculation unit 14 is input to a variance value calculation unit 16, a power calculation unit 18, and a speed calculation unit 20. Here, the variance value calculation unit 16 is a circuit that calculates a variance value related to the spread of the speed based on the Doppler information output from the Doppler information calculation unit 14. The power calculator 18 is a circuit that calculates power based on the Doppler information output from the Doppler information calculator 14. The speed calculation unit 20 is a circuit that calculates a blood flow speed (average speed) based on the Doppler information output from the Doppler information calculation unit 14. These operation units 16, 1
8, 20 are circuits known per se.

The power image processing unit 22 includes a power calculation unit 18
This is a circuit for forming a power image with respect to the power output from the printer. Specifically, as described later, the luminance of a predetermined color is determined in accordance with the magnitude of the power. Also,
The speed image processing unit 24 forms a speed image according to the speed output from the speed calculation unit 20. Specifically, the speed image processing unit 24 determines the luminance of a predetermined color in each of the positive direction and the negative direction of the speed. doing. 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 switch 30, and as described below, for each sample point (pixel), That image display, that is, the display format is selected.

The variance value from the variance value calculation unit 16 is also input to the speed image processing unit 24, and image processing is performed so that the variance value is reflected in forming the speed image. Specifically, image processing is performed such that colors not used for coloring power and speed are mixed according to the dispersion value.

The display format selector 26 controls the operation of the signal switch 30 based on the variance value for each sample point. Specifically, when the variance is smaller than the reference value stored in the reference value memory 28, a power image is selected for the sample point. On the other hand, when the variance is larger than the reference value, the power image is selected. A velocity image is selected for a sample point. Therefore, one of the display formats is selected for each sample point, in other words, for each pixel. In this case, the image display is performed by the display form based on the power image for the blood flow flowing normally, and the image display is performed by the velocity image for the turbulent flow such as the backflow. Therefore, by looking at the Doppler image constructed by such two types of image formats, as described above, it is possible to clarify the backflow that is actually occurring without being affected by an unsightly apparent backflow or the like. Can be recognized. The coloring method in the power image processing unit 22 and the speed image processing unit 24 will be described later in detail.

FIG. 2 shows the ultrasonic probe 10 shown in FIG.
Are shown. The ultrasonic probe 10 is a blood vessel 20
0, a rotating wire 42 that rotates in the catheter 40, and an ultrasonic vibrator 44 provided at a distal end of the rotating wire 42,
Further, a drive motor for rotating a rotating wire (not shown) is included.

The ultrasonic transducer 44 is provided to be inclined at a fixed angle with respect to the central axis of the rotating wire 42. Therefore, the ultrasonic beam 100 and the central axis of the rotating wire 42 intersect at a fixed angle. ing. Therefore, the rotating wire 42
Is rotated, a conical data capturing area can be formed. If the direction of the ultrasonic beam 100 is oriented in a direction orthogonal to the axial direction of the rotating wire 42, the ultrasonic beam 100 is orthogonal to the blood flow, and there is a problem that Doppler information cannot be obtained. However, 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.

FIG. 3 shows the ultrasonic probe 10 shown in FIG.
Thus, for example, a problem in a case where an ultrasonic diagnosis is performed in a bent aorta is shown. As shown in FIG. 3, the blood vessel 200 is partially bent, and when the ultrasonic beam is rotated and scanned in such a state, the ultrasonic beam 100A in one direction and the ultrasonic beam in another direction are different. With 100B, velocity components of different polarities are detected even though they have the same blood flow. That is, although the blood flow originally approaches the ultrasonic probe 10, the blood flow is observed on the ultrasonic beam 100B as if it were a blood flow flowing in the opposite direction. In such a state, if the velocity is simply two-dimensionally displayed as in the related art, a backflow which does not actually occur in a partial region in the blood vessel is expressed, and there is a problem that there is a problem in diagnosis.

Therefore, the ultrasonic diagnostic apparatus according to the present embodiment utilizes a power image. That is, if the power at each sample point is imaged, the power itself has no polarity, so that the problem of apparent backflow can be effectively prevented. That is, for example, FIG.
If the power is associated with red in the state shown in FIG. 1, it is possible to display the inside of the blood vessel in red, which causes a problem that the color in the opposite direction (blue) is partially generated as in the related art. Can be resolved.

However, if power is always imaged for each sample point, a problem occurs in the case shown in FIG. In FIG. 4, the blood vessel 200A and the blood vessel 200B are adhered to each other at the site 210, and the 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 to perform ultrasound diagnosis, and only an image of power is formed for each sample point, the backflow of blood at the site 210 where the adhesion has occurred is imaged. A problem arises that it is not possible. Therefore, in the embodiment shown in FIG. 1, when the backflow actually occurs as shown in FIG. 4, the above problem is solved by switching the display format of the sample point to the display format of the speed. In this case, if such a backflow occurs, the variance value increases, and thus the variance value is used as a criterion in selecting the display format.

That is, as shown in FIG. 1, a power display format is selected for a normal sample point having a variance value smaller than the reference value, while a turbulence sample point having a variance value larger than the reference value is selected. Indicates that the speed image display is selected. In this manner, by determining the presence or absence of turbulence, that is, backflow at each sample point, it is possible to construct a Doppler image that is faithful to the actual blood flow that is not disturbed by apparent backflow, thereby enabling disease diagnosis. Accuracy can be improved.

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 performs speed coloring according to the coloring function shown in FIG. In this example, the yellow luminance is set to gradually increase in the positive direction of the speed, while the green luminance is set to gradually increase in the negative direction of the speed. Also, as shown in (B), the power image processing unit 2
In 2, the coloring function is set such that the luminance of red gradually increases as the power increases.

By using such a function,
Red can be used as a standard in the expression of normal blood flow, and if turbulence occurs in a certain part of the blood vessel, color it yellow or green according to the flow direction at each sample point Becomes possible. As a result, in many cases, green dots appear densely in red, which makes it possible to grasp at a glance that backflow has occurred. Also, even in the case of a forward flow, an extremely high-speed flow or the like is expressed in yellow, so that such a state can be easily grasped. 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 for any direction. Alternatively, the absolute value of the speed may be calculated, and a specific color, for example, blue, may be defined for the absolute value. Furthermore, when viewed as a whole in a blood vessel, the flow of blood flow is defined as a main direction, and the speed of the main direction is expressed in the same color as power, and the direction different from the main direction is expressed in a color different from power. 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.

In the above embodiment, the configuration in which the ultrasonic vibrator rotates is shown. However, the present invention can be applied to a case where a non-rotating ultrasonic probe is used. Further, in the above embodiment, the ultrasonic vibrator is disposed at an angle, but the present invention is not limited to this.

[0037]

As described above, according to the present invention,
When displaying a two-dimensional Doppler image, it is possible to express the actual backflow clearly 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 apparent backflow occurs.

FIG. 4 is a diagram showing a backflow of blood due to adhesion of blood vessels.

FIG. 5 is an explanatory diagram showing a coloring function.

[Explanation of symbols]

10 ultrasonic probe, 14 Doppler information calculation unit, 16
Variance calculator, 18 power calculator, 20 speed calculator,
22 power image processing unit, 24 speed image processing unit, 26
Display format selection unit, 30 signal switch.

Claims (5)

[Claims] 1. An ultrasonic diagnostic apparatus that processes Doppler information included in a reception signal obtained by transmitting and receiving ultrasonic waves to display an ultrasonic image, wherein a turbulent flow is generated for each sample point based on the Doppler information. Turbulence determination means for determining the presence / absence of turbulence; and selecting a first image display for sample points for which turbulence is not determined in displaying motion information for each sample point; And a selecting unit for selecting a second image display different from the first image display. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the first image display performs coloring independent of the flow direction, and the second image display performs coloring depending on the flow direction. An ultrasonic diagnostic apparatus characterized by being performed. 3. An ultrasonic diagnostic apparatus which processes Doppler information included in a reception signal obtained by transmitting and receiving ultrasonic waves to display an ultrasonic image, wherein a power operation for calculating a power based on the Doppler information is performed. Means, speed calculation means for calculating a speed based on the Doppler information, variance calculation means for calculating a variance value based on the Doppler information, and for each sample point, the variance value according to the magnitude of the variance value An ultrasonic diagnostic apparatus comprising: a selection unit that selects an image display of power or an image of the speed. 4. The apparatus according to claim 3, wherein the selecting means selects the image display of the power at a normal sample point at which the variance is smaller than a predetermined value, and selects the turbulent flow at which the variance is larger than a predetermined value. An ultrasonic diagnostic apparatus, wherein an image display of the speed is selected for a sample point. 5. The ultrasonic diagnostic apparatus according to claim 3, wherein different colors are used for the power image display and the speed image display.