JPS6257540A - Blood stream imaging apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention transmits and receives ultrasonic waves within a subject by sector scanning, and detects the inside of the subject based on the scattered ultrasound caused by the transmitted and received ultrasonic waves. A blood flow imaging device that obtains blood flow information data and performs imaging is designed to prevent deterioration of image quality at the turning point, especially when the flow velocity changes rapidly from one order to the other (or from the other way to the order). The present invention relates to a blood flow imaging device.

[Technical background of the invention and its problems]

An electronic scanning type ultrasound diagnostic device is used as a blood flow imaging device using ultrasound, and when ultrasound is transmitted and received at the same location within the subject by, for example, sector scanning, the echo component is lf[ Focusing on the fact that the blood flow information undergoes frequency deviation according to the velocity component of the I flow, phase detection is performed on the echo component to extract only the frequency deviation component, and frequency analysis of the signal is performed. Some devices display blood flow information such as the average blood flow velocity and its variance as the analysis results. Furthermore, in the B-mode image obtained by the sector scanning, the blood flow information is sometimes displayed in a two-dimensional manner, for example, by coloring forward flow in red and reverse flow in blue.

In this case, in the blood flow information data obtained by ultrasonic sector scanning, linear interpolation of N-1 points on an arc is performed between adjacent true data of the ultrasonic raster, and ultrasonic sector scanning and TV scanning are performed. We are trying to respond to these issues. However, if linear interpolation is performed on all data, if the aliasing phenomenon occurs, that is, the flow velocity changes rapidly from one order to the other (or vice versa), the aliasing blood spots will be displayed in black, which is caused by Red is defined as forward flow and blue is defined as reverse flow, but a black display with no definition appeared, and it could not be said that correct diagnostic information was shown.

Here, when the sampling interval is T and the frequency of blood flow is f, when f > 1/2T, a positive (
This is a phenomenon that exceeds the maximum value of the flow velocity (or negative) and appears in the region of the maximum negative (or positive) value, as shown in Figure 6.
The part B appears as a backward flow region A' when the forward flow frequency Wlf>1/2T, and the part B appears in the forward flow region B' when the reverse flow frequency Wlf>1/2T. There is.

FIG. 7 shows how the data at the turning point is linearly interpolated. In this case, it is assumed that there are three interpolated data, which are blood flow data obtained by transmitting and receiving ultrasonic waves four times.

In FIG. 7, sampling data (true data) 2 following true data 1 appears in a reverse flow region due to aliasing. At this time, if the forward flow is displayed in red and the reverse flow is displayed in blue light, and the display becomes black as the flow speed becomes slower, the interpolated data will be dark red (interpolation 1) and black (interpolation 2).
, dark blue (interpolation 3), and an undefined display appears between red and blue, resulting in overall deterioration of image quality.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its object is to provide blood flow imaging that prevents deterioration of image quality at a turning point when the flow velocity changes rapidly from one direction to the other (or from the other direction to the next direction). The goal is to provide equipment.

[Summary of the invention]

In order to achieve such an object, the present invention transmits and receives ultrasonic waves to the same location within the subject N times by sector scanning, and generates blood flow information data within the subject based on the scattered ultrasonic waves resulting from the transmitted and received ultrasonic waves. A blood flow imaging apparatus configured to perform imaging based on blood flow information includes a plurality of storage means for storing the blood flow information data, a storage control means for controlling input and output of the plurality of storage means, and a plurality of storage means for controlling the input and output of the plurality of storage means. a first selection means for selecting an output; a multiplication means for multiplying the output selected by the first selection means by the number 31; a coefficient control means for changing this coefficient; and an addition for adding the outputs of the multiplication means. and second selection means for selecting the output of the first selection means and the output of the addition means according to the output of the first selection means, wherein the blood flow information data is The data is input to one of the plurality of storage means at every N rate of sound wave transmission, and the other storage means repeatedly outputs the data input at least once and twice before N-1 times for each rate. These output data are controlled by the storage control means, and after being selected by the first selection means, are multiplied by the coefficients changed for each rate by the multiplication means, and these multiplied data are The addition means adds N-1 interpolated data for each rate, and uses these N-1 interpolated data to linearly interpolate N-1 points on an arc between adjacent true data. The second selection means selects the output of the first storage means instead of the output of the addition means in accordance with the output of the first storage means, and the previous true data itself is selected for each rate. N
−1 interpolated data, and these N−1 interpolated data ~
It is characterized by a configuration in which interpolation is performed on a circular arc between adjacent true data.

[Embodiments of the invention]

An embodiment of the blood flow imaging device according to the present invention will be described below with reference to the block diagram shown in FIG. 1, which is applied to a sector electronic scanning ultrasound diagnostic device.

In FIG. 1, reference numeral 1 denotes an ultrasonic probe consisting of a large number of ultrasonic transducers arranged in parallel, and this probe 1 receives ultrasonic pulses that are controlled to have a predetermined transmission delay in order to be scanned in sectors. to each ultrasonic transducer, and the echo signal from each ultrasonic transducer is given a reception delay of 1l corresponding to the above transmission delay.
ilJ l[lt, is electrically connected to the receiver group 3 which receives the signal. Reference numeral 4 denotes an adder for adding analog signals received from each transducer from the receiver group 3, and the addition output of this adder 4 is given to a B-mode image processing system and a blood flow imaging processing system, which will be described later.

The B-mode image processing system includes a detector 5. which detects the addition output of the adder 4. A/ which converts the detection output of the detector 5 into a digital signal
D converter6. A frame memory 7 generates one frame B-mode image based on the echo information converted into a digital signal by the A/D converter 6.

The blood flow imaging processing system includes a phase detector 81 that performs phase detection on the addition output of the adder 4 to obtain a frequency-shifted signal.
A/A for converting the phase detection output of the phase detector 8 into a digital signal
D converter9. Based on the phase detection output converted into a digital signal by the A/D converter 9, blood flow data such as the average flow velocity and its dispersion are calculated for each ultrasonic rask, color-processed such that red indicates forward flow and stomach flow is reflux. Arithmetic unit 10. A calculation unit 11 that uses blood flow data for each ultrasound rask from the calculation unit 10 to associate data between ultrasound sector scanning and TV scanning by data interpolation. It consists of a frame memory 12 that generates one frame blood flow imaging image based on the correction data from the calculation section 11.

13 is a synthesizer for synthesizing the frame mode image from the B-mode image processing system and the frame blood flow imaging image from the blood flow imaging processing system to obtain an image in which both are superimposed; 14;
15 is a D/A converter that converts the synthesized image obtained by superimposing the B-mode image and blood flow imaging image from the synthesizer 13 into an analog signal, and 15 converts the synthesized image converted into an analog signal by the D/A converter 14 into a color image. This is a display system that displays images.

In the above, the detailed configuration of the interpolation section 11 is shown in FIG. In FIG. 2, 21 is a first buffer into which blood flow data for each ultrasonic rask from the calculation unit 10 is input, and a second buffer 22 is connected to the rear stage. 23
is also a third buffer into which blood flow data is input, and a fourth buffer 4 is connected to the subsequent stage. These buffers 21゜22, 23, 24 have an input to the E terminal of °″0″.
When , the input data is output, and when it is "1", the output becomes high impedance and the memory 25 is connected to the subsequent stage.
．． 26.27.28.

These memories 25, 26, 27, and 28 perform a write operation, that is, write data from the pair of buffers (21, 22, 23° 24) in the previous stage, when the input to the R/W terminal is 0''. 1", read operation, that is, output the stored data. 29 is the first memory 25
a first multiplexer 30 that inputs the memory contents of the third memory 27 to the terminal 8 and the memory contents of the third memory 27 to the terminal A;
is a second multiplexer which inputs the memory contents of the second memory 26 to the B terminal and the memory contents of the fourth memory 28 to the A terminal, respectively.

These multiplexers 29 and 30 connect the data input to the △ terminal when the input to S@ is O゛', and the data input to the B terminal when the input is ゛1 to the subsequent stage. The signal is output to the A terminals of the first multiplier 31 and the second multiplier 32.

Arbitrary coefficients are input to the B terminals of these multipliers 31 and 32, respectively, and the multipliers 31 and 32 multiply the input of the other terminal A by the input of the 8 terminals, and output the data to the 8 terminal of the adder 33 and the A terminal.
Output to the terminal. This adder 33 adds the two human forces and outputs the result as output data. 34 is a memory controller;
An address signal S1 for setting the address of each memory 25°26.27.28; Third buffer 22.23
and second. A read/write control signal S2 that controls the third memory 26, 2A, and a read/write control signal S2 that controls the third memory 26, 2a; Fourth buffer 21.24
and 1st. The read/write control signal S3 controls the fourth memory 25, 28, and the first memory 25,28. Second multiplexer 29
．． 30 inputs and generates a select signal S4.

35 is a coefficient suppressor which outputs an UP coefficient to the first multiplier 31 and a DOWN coefficient to the second multiplier 32.

36 is a select signal S5 of the final stage multiplexer 37
It is a controller that generates. 37 is a multiplexer, which will be explained with reference to a mink chart of the output of the adder 33 and the output of the multiplexer 30 based on the output S5 of the controller 36. In this case, in order to simplify the explanation, a mode is assumed in which the ultrasonic beam is transmitted and received four times to scan the same location on the subject. In Figure 3, ■~■ are the ultrasound transmission directions, ■'~■' are the data for the wave transmission directions, T1 is the ultrasound beam transmission timing, T2 is the input data capture timing, and RD is the data for each memory. A read operation and WR indicate a write operation of each memory.

First, the data ■- obtained by transmitting the ultrasonic beam four times in the direction of ■ is delayed by two rates from the rate of the last fourth transmission in the direction of ■, due to arithmetic processing. It is output (T2). The same applies to ■- to ■'.

This output ■' is simultaneously input to the first buffer 23, but the memory controller 34 receives the read/write control signal $
3 is “O” and S2 is “°1”, the signal passes only through the first buffer 21 and is written into the first memory 25.

At this time, since the read/write control signal S2 input to the R/W terminals of the second and third memories 26 and 27 is "1", the second. The third memories 26 and 27 read invalid (INVALID) data, and since the read/write control signal S3 is 0'', the invalid data read from the third memory 27 is transferred to the fourth buffer 24.
and is written to the fourth memory 28.

At the first rate of the capture cycle of the next input data ■-, the read/write control signal S2 is "o", so the data ■' passes through the third buffer 23 and is written to the third memory 27. . At this time, since the read/write control signal S3 is 1'', the first memory 25 reads the data - written in the previous cycle, and the fourth memory 28 reads invalid. Signal S
Since 4 is "1", the data ``■'' read out from the first memory 25 is output from the first multiplexer 29. Further, since the read/write control signal $2 is 110 I+, data ■' passes through the second buffer 22 and is written to the second memory 26.

Furthermore, at the first rate of the capture cycle of the next input data ■-, the read/write control signal S3 is "Opa", so the data ■- passes through the first buffer 21 and is written to the first memory 25. It will be done.

At this time, since the read/write control signal S2 is 1'',
The third memory 27 is the data written in the previous cycle.
, and data ■' written in the previous cycle of the second memory 26 is read and output to the second multiplexer 30. Further, since the read/write control signal S3 is 11011 in the fourth memory 28, the read/write control signal S3 is
The data ■′ read in is written.

Here, since the select control signal S4 is 'O'', the data - read out in the second memory 26 passes through the second multiplexer 30 and is sent to the second multiplier 32, and the third The data ■- read out in the memory 27 of
The signal passes through two multiplexers and is sent to the first multiplier 31.

At the first rate of data acquisition, the DOWN coefficient is set to the maximum value of 1, so the data - sent to the second multiplier 32 is multiplied by 1 and sent to the B input terminal of the adder 33. It will be done. On the other hand, since the UP coefficient is set to the minimum value O, the data ■' sent to the first multiplier 31 is multiplied by O and sent to the B input terminal of the adder 33. This adder 33 adds 1X■- and Ox■' and outputs ■' as output data.

At the next rate, the read/write control signal S3 becomes 1, but since the other control signals 32 and 34 remain the same, the data ■' is sent to the second multiplier 32, and the data ■-
is sent to the first multiplier 31. At this time, the UP coefficient is 1/4. Since the DOWN coefficient has changed to 3/4, the data ■- is multiplied by 3/4 in the second multiplier 32, while the data ■- is multiplied by 1/4 in the first multiplier 31. is output to the adder 33, where it is added (3■-t■-
)/'4 is output as output data.

At roughly the next rate, data ■-1 is read from the second memory 26 and data ■- is read from the second memory 27, and the UP coefficient is 2/4 and the DOWN coefficient is 2/4.
The output of the adder 33 is (2■-+2■-)/
It becomes 4.

Also, at the next rate, the UP coefficient becomes 3/4, and the DO
The WN coefficient changes to 1/4, and the output of the adder 33 becomes (■
'+3■')/4.

Similarly, at the first rate of the acquisition cycle of the next data ■-, the output of the adder 33 is (3
■−+2■′)/4, and roughly the next rate is (■−+2■′)/4.
+3■-〉/4.

When transmitting and receiving ultrasound beams to the same place four times in this way, three interpolated data are calculated and determined based on two adjacent true data, and a fourth Figure (a
) As shown in (b), linear interpolation data can be generated by arranging them in the arc direction.

Furthermore, in this timing chart, if the data of ■- and ■' are data due to folding (data in which the blood flow directions of ■' and ■' are different), the output S5 of the controller 36 will be 0'', and the output of the multiplexer 37 will be The output of the multiplexer 30 is generated as interpolated data (output S5 of the controller 36
is "1" if the outputs of the multiplexers 29 and 30 are blood flows in the same direction, and "Opa" if the outputs are not in the same direction.)

Multiplexer 37 selects B if S5 is 1'';
If is °゛○'', select A. Therefore, by performing a plurality of linear interpolations between new data, it is possible to improve the image quality even if the spacing between scanning lines is quite wide.

Although one embodiment of the present invention has been described above in detail, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the gist. For example, if an ultrasound beam is transmitted and received N times at the same location, the UP coefficient is 0.1/N...(N-
1)/N, while the DOWN coefficient is 1. (N-1)
/N...changes to 1/N, and changes the adjacent true data tube (
N-1) This linear interpolation can be performed. The case of folding according to this embodiment is shown in FIG. 5 using the data in FIG. 7.

Furthermore, in the above embodiment, an example was described in which a B-mode image and weight are displayed in combination with an ultrasound diagnostic device that obtains a B-mode image, but a configuration that displays only blood flow imaging, that is, the B-mode image signal processing system is removed. It may also be applied to the configuration.

(Effects of the Invention) As detailed above, according to the present invention, when displaying blood flow information by transmitting and receiving an ultrasonic beam N times at the same location by sector scanning, the difference between adjacent true data is (N -1>(ii
Linear interpolation is performed on the arc using the interpolated data of l, and if the adjacent true data is data in a different direction due to folding, linear interpolation is not performed and the true data itself is (N-1)
Since the interpolation is performed on a circular arc, it is possible to provide a blood flow imaging device that improves image quality without turning the edges of folds into black.

[Brief explanation of drawings]

FIGS. 1 and 2 each show a practical example of a blood flow imaging device according to the present invention. FIG. FIG. 4(a) is a timing chart showing the timing of the number of times, and FIG.
b) is a partially enlarged view, FIG. 5 is a diagram explaining folding interpolation using the interpolation method according to the same embodiment, FIG. 6 is a diagram showing folding in the same embodiment, and FIG. 7 is a diagram showing conventional interpolation. FIG. 3 is a diagram illustrating folding interpolation using the method. DESCRIPTION OF SYMBOLS 1... Ultrasonic probe, 2... Transmitter group, 3... Receiver group, 4... Adder, 5... Detector, 6... A
/D converter, 7... Frame memory, 8... Phase detector, 9... A/D converter, 10... Arithmetic unit, 11
...Interpolation unit, 12...Frame memory, 13...
Synthesizer, 14... D/A converter, 15... Display system,
21,22.23.24...buffer, 25.26.
27.28...Memory (storage means), 29.30...
・Multiplexer (first selection means), 31.32...
- Multiplier (multiplication means), 33... Adder (addition means)
, 34... memory controller (storage control means), 35...
- System controller (counting control means), 36... Controller, 3
7 river multiplexer (controller 36 and multiplexer 37
and the second selection means). Applicant's agent Patent attorney Takehiko Suzue (a) (b > Figure 4 Figure 7 2

Claims (1)

[Claims] Blood flow in which ultrasonic waves are transmitted and received N times at the same location within the subject's body by sector scanning, and blood flow information data within the subject's body is obtained and imaged based on the scattered ultrasound waves caused by the transmitted and received ultrasound waves. In the imaging apparatus, a plurality of storage means for storing the blood flow information data, a storage control means for controlling input and output of the plurality of storage means, and a first selection means for selecting outputs of the plurality of storage means. , a multiplication means for multiplying the output selected by the first selection means;
a coefficient control means for changing the coefficient; an addition means for adding the output of the multiplication means; and an output of the first selection means and the output of the addition means in accordance with the output of the first selection means. a second selection means for selecting, the blood flow information data is inputted into one of the plurality of storage means at every N rate of the number of ultrasound transmissions, and the other storage means is inputted to one of the plurality of storage means at least once and two times before. The data entered in the previous
- controlled by the storage control means so as to be output repeatedly once; these output data are selected by the first selection means and then multiplied by the coefficients changed for each rate by the multiplication means; The multiplied data are added by the adding means to obtain N-1 interpolated data for each rate, and these N-1 interpolated data are used to divide adjacent true data at N-1 points on the arc. linear interpolation is performed, and the output of the first storage means is used instead of the output of the addition means according to the output of the first storage means to the second storage means.
The previous true data itself is obtained as N-1 total interpolated data for each rate, and this N-
A blood flow imaging apparatus characterized in that a single piece of interpolation data is used to perform interpolation between adjacent true data on an arc.