JPH0678924A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To obtain the blood flow speed of a desired portion easily without complicated operation by detecting the blood flow direction from the speed distribution condition in an area inside a tomographic image specified by a specifying means, and computing the blood flow speed from the blood flow direction. CONSTITUTION:At the time of receiving a reflection echo of an ultrasonic probe by the ultrasonic probe 1 and outputting the same to a display part 5, a doppler arithmetic part 3 obtains the speed distribution in a specified beam direction of a tomographic image. A color doppler arithmetic part 4 obtains speed information on all points in the respective beam directions of a tomographic image, and two-dimensional speed information is pseudo-colored to obtain a color doppler image. In the case of obtaining the blood flow speed in a blood vessel of a tomographic image, the doppler sample points are displayed by operating a console 7, and an area of a fixed width centering round the sample points is specified by a blood speed distribution extract part 8. Subsequently, a blood flow direction arithmetic part 9 computes the blood flow direction from the speed distribution condition of an area corresponding to a specified area, and the blood flow speed is computed from the blood flow direction by means of a main controller 10.

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 capable of obtaining blood flow velocity information using a so-called Doppler measurement method.

[0002]

2. Description of the Related Art When the blood flow velocity is obtained by using the Doppler measurement method, the blood flow velocity v'detected by the ultrasonic diagnostic apparatus itself is detected.
Is v ′ = v · cos θ. Here, v is the actual blood flow velocity, and θ is the angle between the blood flow direction and the Doppler beam direction.

Therefore, in order to obtain the actual blood flow velocity v, the following equation

[0004]

## EQU1 ## v = v '/ cos θ …………………
(1) needs to be calculated, but the value of θ needs to be known before that.

In order to detect the value of θ, conventionally,
First, a tomographic image including blood vessels is displayed on a display device (CRT), and a bar having a predetermined length centering on the Doppler sample point is displayed by an appropriate operation using an operation console. Then, likewise, the bar is rotated about its center point by the appropriate operation by the console so that the bar coincides with the blood flow direction.

As a result, the apparatus itself detects the direction (angle θ) of the bar matched with the blood flow direction, and the actual blood flow velocity v is calculated by using the above-mentioned equation (1). Has become.

[0007]

However, the ultrasonic diagnostic apparatus configured as described above must perform a rotating operation for matching the displayed bar with the blood flow, and the examination site is Since the same operation must be repeated each time it changes, there remains a problem that the operation was extremely complicated.

Further, there is a problem that such an operation is often forgotten, which may cause a misdiagnosis.

Therefore, the present invention has been made under such circumstances, and the object of the present invention is to be able to automatically calculate the actual blood flow velocity without complicated operations. It is to provide an ultrasonic diagnostic apparatus capable of performing

[0010]

In order to achieve such an object, an ultrasonic diagnostic apparatus according to the present invention basically comprises a display device for displaying a tomographic image including blood flow, and a display device for displaying the tomographic image. A memory for storing velocity information in each pixel corresponding to an image, an instruction means for instructing a portion where the velocity in the blood flow is to be obtained, and a constant width centered on the portion instructed by the instruction means Designating means for designating an area, detection means for detecting a blood flow direction from a velocity distribution state in the area of the memory corresponding to the area designated by the designating means, and blood flow direction detected by the detecting means And a calculating means for calculating the blood flow velocity in the blood flow direction.

[0011]

According to the ultrasonic diagnostic apparatus configured as described above,
First, while observing a display device that displays a tomographic image including blood flow, the pointing means is used to point to a location where the velocity in the blood flow is to be obtained.

Then, the designating means designates a region having a predetermined width centered on the location designated by the designating means.

On the other hand, a memory for storing velocity information in each pixel corresponding to the image on the display device is provided, and the blood flow is calculated from the velocity distribution state in the region of the memory corresponding to the region designated by the designating means. The direction is detected by the detecting means.

The blood flow velocity in the blood flow direction is calculated by the calculation device from the blood flow direction detected by the detection device.

From this fact, since the actual blood flow velocity can be automatically calculated only by the operation of designating the place where the blood flow velocity is to be obtained, it is not necessary to perform a complicated operation.

[0016]

FIG. 2 is a schematic block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention.

First, there is an ultrasonic probe 1 which is used by being brought into contact with the body surface of a subject. The ultrasonic probe 1 is configured to irradiate ultrasonic waves into the subject by driving the ultrasonic wave transmission / reception control unit 2.

The emitted ultrasonic waves are reflected echoes which are input to the ultrasonic probe 1, and the received signals are amplified and detected by the ultrasonic wave transmission / reception control unit 2 and output to the display unit 5. Has become. This display unit 5 is, for example, a CRT.
The tomographic image of the subject is displayed. Then, in this embodiment, the tomographic image is an image including blood flow.

Further, there is a Doppler calculation unit 3, and this Doppler calculation unit 3 is adapted to obtain the velocity distribution of one point or several points in the specific beam direction of the tomographic image. The velocity distribution for several seconds is displayed as a Doppler image on the screen.

Further, there is a color Doppler calculation unit 4, and this color Doppler calculation unit 4 is adapted to obtain velocity information of all points in each beam direction of the tomographic image. The color Doppler image is constructed by converting the dimensional speed information into pseudo color corresponding to the size of the speed. Here, normally, the color Doppler image is displayed on the display unit 5 so as to be superimposed on the tomographic image.

Here, the color Doppler image is inferior to the mere Doppler image in the velocity accuracy of the blood flow velocity, but has the advantage that the two-dimensional blood flow distribution can be observed in real time.

Further, there is an angle correction unit 6, which is conventionally provided, and is capable of detecting the direction of blood flow by manual operation. That is, as shown in FIG.
The tomographic image 32 including 1 is displayed on the display unit 5, and the angle correction bar 34 having a predetermined length centering on the Doppler sample point 33 is displayed by an appropriate operation using the operation console 7. Then, again, as shown in FIG. 3B, the angle correction bar 34 is rotated about the center point thereof so as to be aligned with the blood flow direction by an appropriate operation on the operation console 7. . As a result, the Doppler wave 35 displayed near the tomographic image 32 is displayed as being along the blood flow direction.

In this embodiment, a new mechanism for automatically calculating the blood flow direction without using the angle correction unit 5, that is, the blood flow velocity distribution extraction unit 8 and the blood flow direction calculation is used. A blood flow velocity distribution variation calculation unit 11 and a blood flow direction setting determination unit 13 are provided, and the blood flow velocity distribution extraction unit 8, the blood flow direction calculation unit 9, and the blood flow velocity distribution variation calculation unit 11 are provided. , And the blood flow direction setting determination unit 13 will be described in detail later.

The above-mentioned blocks are controlled by the main controller 10 having a CPU, and
The main controller 10 is adapted to be given a command by the console 7.

Next, the blood flow velocity distribution extraction unit 8 and the blood flow direction calculation unit 9 newly provided in this embodiment will be described.

Blood flow velocity distribution extraction unit 8 In response to an instruction from the console 7, a Doppler sample point 23 is set at a position of the blood vessel 22 in the tomographic image 21 displayed on the display unit 5 where the blood flow velocity is to be obtained. indicate. The relationship between the tomographic image 21 and the Doppler sample points 23 is shown in FIG. In the same figure (a), it is shown that the Doppler sample point 23 is located in a part of the blood vessel 22.

Then, the blood flow velocity distribution extraction unit 8 is designed to specify a region having a constant width with the Doppler sample point 23 as the center. In this embodiment, as shown in FIG. 1B, the width is x = 3, x = −3, y = 3, y = using the sample point as the origin (0, 0).
7 × 7 pixels in the area surrounded by -3 are designated.

Then, the speed information of each pixel corresponding to the area in the color Doppler image is read out. The speed information of each pixel thus obtained is
For example, as shown in (b) of the figure, it is represented by a point having a diameter according to the velocity, and is information indicating the velocity distribution itself.

Blood flow direction calculation unit 9 From the velocity distribution shown in FIG. 1B, a straight line passing through the sample points: y = ax is obtained by the so-called least squares method. This straight line: y = ax is a straight line matched along a relatively high velocity portion of the velocity distribution, and is matched with the blood flow direction. The slope a of the straight line becomes a value indicating the direction of blood flow.

The method of calculating a using the least squares method will be described below.

The velocity information at each pixel is represented by Xi, Yi, V
i (i = 1, ..., N), and Doppler sample point 2
A straight line having a slope matching the blood flow direction passing through 3 is assumed to be y = ax.

The ordinate Y'of this straight line with respect to the abscissa Xi
The ordinate difference between i and the point (Xi, Yi) can be expressed by the following equation.

[0033]

## EQU00002 ## Yi-Y'i = Y-aXi ..........
(2) Here, according to the generally known least-squares method, it is only necessary to obtain a such that the sum of the squares of the above equation becomes the minimum. However, in this embodiment, the above equation (2) is weighted by the velocity value,

[0034]

[Equation 3]

The value a that minimizes is calculated. Equation (3)
Is transformed into

[0036]

[Equation 4]

[0037] In the above equation, the only variable is a, so

[0038]

[Equation 5]

At the time of, the above equation (3) becomes the minimum. That is, a obtained from the equation (5) is the direction of blood flow to be obtained.

Further, by replacing X and Y, a straight line x = a'y
When assuming,

[0041]

[Equation 6]

Can be obtained as the direction of blood flow.
Further, it goes without saying that the blood flow direction may be obtained by averaging the above equations (5) and (6).

In order to further simplify such calculation, another calculation method will be described. The velocity value of each pixel in the designated area is binarized. That is, it is determined whether or not there is blood flow, and the calculation is performed only on the coordinates of the pixel determined to have blood flow. Let N ′ (<N) be the total number of pixels, and Vi = 1 for the above equation (3).
If is set, the equation (3) becomes

[0044]

[Equation 7]

It becomes like. The same applies to the equation (6).

Further, in this embodiment, a mechanism is provided for checking whether or not the blood flow direction a calculated by the blood flow direction calculation unit 9 matches the actual blood flow direction. This mechanism is configured by a blood flow velocity distribution variation degree calculation unit 11 and a blood flow direction determination unit 13 in FIG. 1. The reason for providing such a mechanism is extremely small in probability, but when the velocity distribution happens to be equalized around the sample point, the blood flow direction a may not be accurately calculated. Is.

This mechanism is designed to be operated in the steps shown in FIG.

Step 1. From the blood flow velocity distribution extraction unit 8, the blood flow velocity distribution is read from a fixed area centered on the Doppler sample point 33. In addition, a straight line indicating the blood flow direction obtained from the blood flow direction calculation unit 9 is read out: y = ax.

Step 2. Variance degree k of blood flow velocity distribution for the straight line: y = ax
To calculate. The variation degree k is calculated based on the following equation, for example.

[0050]

[Equation 8]

This calculation is performed by the blood flow velocity distribution variation calculation unit 11.

Step 3. It is determined whether or not the calculated variation degree k is larger than the variation degree K obtained in advance.

Here, the variation degree K obtained in advance is
It is a value set when the blood flow direction obtained by the calculation is equal to or almost equal to the actual blood flow direction, and is obtained based on the above-mentioned equation (8).

This determination is performed by the blood flow direction setting determination unit 1
It is supposed to be done by 3.

Step 4. When k> K, it is determined that the blood flow direction obtained by the calculation is not equal to the actual blood flow direction, and therefore the angle correction unit 6 performs correction.

Step 5. In the case of k ≦ K, it is determined that the blood flow direction obtained by the calculation is equal to or substantially equal to the actual blood flow direction, and therefore a is set as the blood flow direction.

According to the ultrasonic diagnostic apparatus according to such an embodiment, first, while observing the display unit 5 which displays a tomographic image including blood flow, the operator console 7 is used to obtain the velocity in the blood flow. It is designed to indicate the location.

Then, an area having a predetermined width centered on the location designated by the console 7 is designated by the designating means.

On the other hand, a memory (color Doppler image) for storing speed information in each pixel corresponding to the image on the display unit 5 is provided, and the area of the memory corresponding to the area designated by the operation console 7 is provided. The blood flow velocity distribution extraction unit 8 extracts the velocity distribution in the blood flow direction, and the blood flow direction is detected from the velocity distribution by the detection means (the blood flow direction calculation unit 9).

Then, the blood flow velocity in this blood flow direction is calculated and calculated by the calculation means (main controller 10) from the blood flow direction detected by this detection means.

From this fact, the actual blood flow velocity can be automatically calculated only by the operation of designating the place where the velocity of the blood flow is to be obtained, so that a complicated operation need not be performed.

In the above-described embodiment, the velocity distribution information is read from the color Doppler image, but it goes without saying that it is not always necessary to read it from the color Doppler image. The point is that the speed information at each pixel corresponding to the image on the display device can be read.

Further, in the above-described embodiment, the blood flow velocity distribution variation degree calculation unit 11 and the blood flow direction setting determination unit 13 are provided, but the blood flow velocity distribution variation degree calculation unit 11 and the blood flow rate variation determination unit 13 are not necessarily required. Needless to say, the flow direction setting determination unit 13 need not be provided. This is because if the calculation of the blood flow direction a is reliable, it is not particularly necessary. In order to make the calculation of the blood flow direction a reliable, for example, a color Doppler image that changes with time is traced back to the past, some information is read, and based on each of these information (for example, at each time This can be done by obtaining the blood flow velocity distribution (by adding or averaging the blood flow velocity distributions of).

In the above-described embodiment, the conventional angle correction unit 6 is left as it is, and the blood flow direction a is obtained even by the manual operation. However, by applying the present invention, Of course, the angle correction unit 6 may be omitted.

[0065]

As is apparent from the above description,
According to the ultrasonic diagnostic apparatus of the present invention, it becomes possible to automatically calculate the actual blood flow velocity without performing a complicated operation.

[Brief description of drawings]

FIG. 1A and FIG. 1B are principle diagrams showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 2 is a schematic block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention.

FIG. 3 is an operation explanatory view showing an example of a conventional angle correction unit provided in the ultrasonic diagnostic apparatus according to the present invention.

FIG. 4 is a diagram showing an operation flow of a mechanism included in the ultrasonic diagnostic apparatus according to the present invention, which mechanism automatically checks the inclination of the blood flow.

[Explanation of symbols]

 21 ... tomographic image, 22 ... blood vessel, 23 ... Doppler sample point.

Claims (1)

[Claims] 1. A display device for imaging a tomographic image including blood flow, a memory for storing velocity information in each pixel corresponding to the image on the display device, and a portion for obtaining velocity in the blood flow. Instructing means for instructing, designating means for designating an area having a constant width centered on the location designated by the designating means, and velocity distribution state in the area of the memory corresponding to the area designated by the designating means An ultrasonic diagnostic apparatus comprising: detection means for detecting a blood flow direction from the blood flow direction; and calculation means for calculating a blood flow velocity in the blood flow direction from the blood flow direction detected by the detection means.