JPH069615Y2 - Ultrasonic diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to the display of a blood flow spectrum based on ultrasonic Doppler.

(B) Conventional technology and its problems In a conventional ultrasonic diagnostic apparatus, a Doppler signal is detected by phase detection of an echo signal obtained by pulse-radiating an ultrasonic beam into a living body, and the Doppler signal is detected by A / After D conversion, for example, fast Fourier transform is performed to obtain the power spectrum of each frequency. As shown in FIG. 2, the horizontal axis represents time,
There is a device in which an image is displayed by making the vertical axis correspond to the blood flow velocity (or frequency) and the brightness to the power of each frequency component.

By the way, when the blood flow velocity is large and exceeds the prescribed flow velocity Vmax determined by the pulse repetition frequency of the ultrasonic beam,
So-called aliasing (foldback phenomenon) occurs, and as a result, the blood flow velocity is displayed in reverse as shown by the portion A in FIG. In the prior art, even if the number of divisions of the blood flow velocity scale can be changed, as shown in FIG. 2, the above-mentioned specified flow velocity Vmax is only displayed as the maximum value of the blood flow velocity. When it occurred, the blood flow value of aliasing could not be read directly. Therefore, conventionally, when aliasing has occurred, it has been troublesome to manually calculate the magnitude of the blood flow velocity.

The present invention has been made in view of such circumstances, and it is possible to switch and display the numerical value on the scale according to the presence or absence of aliasing, so that even if aliasing occurs, the blood of that part can be displayed. The purpose is to make it easy to read the flow velocity value.

(C) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a frequency of an ultrasonic beam pulse-emitted from a probe, a pulse repetition frequency, an incident angle of the ultrasonic beam with respect to a blood flow, and Setting means for setting each value of the division number of the blood flow rate scale, maximum blood flow rate calculating means for calculating the maximum blood flow rate based on the value set by this setting means, and this maximum blood flow rate calculating means The ultrasonic wave provided with a numerical value sequence calculation means for calculating a positive / negative numerical value sequence of the blood flow rate scale corresponding to the number of divisions based on the maximum blood flow rate calculated in step 1 and the value of the number of divisions set by the setting means. In the diagnostic device, a display switching means for switching the numerical display of the blood flow rate scale, and a numerical sequence expanding means for doubling the numerical range in both positive and negative directions in response to a display switching signal from the display switching means, Numerical value sequence expansion The numerical sequence is enlarged twice in means is characterized in that a display address calculating means arranged on the blood flow velocity scale.

(D) Operation In the ultrasonic diagnostic apparatus of the present invention, the frequency of the ultrasonic beam pulse-emitted from the probe by the setting means, the pulse repetition frequency, the incident angle of the ultrasonic beam with respect to the blood flow, and the division of the blood flow velocity scale. When each value of the number is set, the maximum flow velocity calculating means calculates the maximum blood flow velocity based on the value set by the setting means. Then, the value of the maximum flow velocity and the value of the division number of the blood flow velocity scale are sent to the scale numerical value calculating means.

When aliasing occurs, the display switching signal output means operated by the observer outputs a numerical display switching signal. Since this display switching signal is input to the numerical sequence expanding means, the numerical sequence expanding means responds to this signal and the numerical sequence calculated by the scale numerical calculating means based on the maximum blood flow velocity and the number of divisions. 2 in both positive and negative directions
Double up. The display address calculating means arranges the numerical value sequence doubled by the numerical value sequence expanding means on the blood flow rate scale. Therefore, even when aliasing occurs, the size of the aliasing occurrence portion can be directly read by looking at the numerical value on the blood flow rate scale.

(E) Embodiment FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention. In the ultrasonic diagnostic apparatus 1 of this embodiment,
When the power spectrum is displayed as an image, the frequency c of the ultrasonic beam pulse-emitted from the ultrasonic probe 4, the pulse repetition frequency pr, the ultrasonic beam with respect to the blood flow, is set by the setting key 2 as the setting means in advance. Incident angle θ
And the respective values of the division number N of the blood flow rate scale are set.
Each set value is sent to the control circuit 8 via the set value register 6.
Therefore, the control circuit 8 controls the transmission / reception circuit 10 based on this set value, and the pulse repetition frequency pr of the ultrasonic beam emitted from the ultrasonic probe 4 and the incident angle of the ultrasonic beam. Set θ. The transmission / reception circuit 10 gives a drive pulse to the ultrasonic probe 4 based on a control signal from the control circuit 8, and the ultrasonic probe 4 is excited and driven in response to this. As a result, an ultrasonic beam is pulse-emitted from the ultrasonic probe 4 into the living body at regular time intervals. When the ultrasonic wave reflected from the living body is received by the ultrasonic probe 4,
Since an echo signal corresponding to this is output from the ultrasonic probe 4, this echo signal is amplified by the wave transmission / reception circuit 10 and then input to the Doppler signal detection circuit 12. The Doppler signal detection circuit 12 detects the Doppler signal by phase-detecting the input echo signal. The Doppler signal is A / D converted by the A / D converter 14, and then fast Fourier transformed by the fast Fourier transform circuit (FFT circuit) 16 in the next stage to calculate the power spectrum of each frequency. Then, the power spectrum data is temporarily stored in the image display memory 20 via the image selection circuit 18. The power spectrum data stored in the image display memory 20 is read by the control circuit 8 in synchronization with TV scanning, converted into a TV signal by the display circuit 22, and then displayed on the CRT 24. Further, when the power spectrum data is read from the image display memory 20, in parallel with this, the vertical axis and horizontal axis diagrams that give a measure of the blood flow velocity and time are displayed from the graphic display memory 26. Is read out, is combined with the power spectrum data in the display circuit 22, and is then similarly output to the CRT 24.

Next, a circuit configuration for displaying a numerical value as a measure of the blood flow velocity on the blood flow velocity scale (vertical axis), which is a feature of the present invention, will be described.

In FIG. 1, reference numeral 30 is the maximum blood flow velocity Vmax calculated based on the ultrasonic beam frequency c set by the setting key 2, the pulse repetition frequency pr, and the incident angle θ of the ultrasonic beam with respect to the blood flow. It is a flow velocity calculation means. That is, the relationship between the shift frequency d of the ultrasonic beam and the blood flow velocity V has the following relationship, where C is the speed of sound.

d = 2Vc · cos θ / C (1) In this case, the maximum value dmax of the shift frequency d in the pulse Doppler method is dmax = pr / 2 (2) from the sampling theorem, so it corresponds to the maximum shift frequency dmax. The maximum value Vmax of the blood flow velocity to be applied is given by Vmax = prC / (4ccos θ) (3) from the equations (1) and (2). Therefore, the maximum blood flow velocity calculation means 30 calculates the maximum value Vmax of the blood flow velocity based on the above equation (3).

32 is the maximum blood flow velocity calculated by the maximum blood flow velocity calculation means 30.
Numerical value sequence calculating means for calculating positive and negative numerical value sequences of each blood flow rate scale corresponding to the number of divisions N based on the value of the number of divisions N set by Vmax and the setting key 2, The divider 34 that divides by the number of divisions N, and the divider 3
And a numerical value string output means 36 for sequentially multiplying the divided value M of 4 by an integer and outputting each positive and negative value obtained by multiplying the integer.

Reference numeral 38 is a numerical value display switching key as a display switching means for switching the numerical value display of the blood flow rate scale. The numerical value display switching key 38 outputs a display switching signal by an observer's operation corresponding to the presence or absence of aliasing. It has become. 40 is a numerical display switching key 38
In response to the display switching signal from, the numerical value sequence expanding means doubles the numerical value sequence in both the positive and negative directions. That is, the numerical value string expanding means 40 sets the coefficient value k to "2" when the display switching signal output from the numerical value display switching key 38 is "H" level, and the coefficient value k when it is "L" level. A coefficient selecting unit 42 that outputs “1” as k, a multiplier 44 that multiplies the coefficient value k from the coefficient selecting unit 42 by the number of divisions N, and a counter 46 to which the value of the multiplication result of the multiplier 44 is set. Composed of and.

Reference numeral 48 is a character code conversion circuit for converting each numerical value output from the numerical value string output means 36 into character reading code data. Further, 50 is a character display memory for storing a character code, and 52 is a display of the enlarged portion of the numerical sequence enlarged by the numerical sequence enlarging means 40, arranged corresponding to the blood flow velocity at the aliasing occurrence portion. This is a display address calculation means, and the display address calculation means 50 designates the writing address of the character code to the character display memory 50.

In the ultrasonic diagnostic apparatus 1 of this embodiment, a blood flow rate scale
To display a numerical value as a measure of the blood flow velocity on the (vertical axis), use the setting key 2 to set the ultrasonic beam frequency c, the pulse repetition frequency pr, the ultrasonic beam incident angle θ to the blood flow, and When each value of the division number N of the blood flow rate scale is set, these values are given to the maximum blood flow rate calculation means 30 via the set value register 6. Further, the data of the division number N is given to the divider 34 and the multiplier 44, respectively. The maximum blood flow velocity calculation means 30 calculates the maximum blood flow velocity Vmax from the values of the ultrasonic beam frequency c, the pulse repetition frequency pr, and the incident angle θ of the ultrasonic beam with respect to the blood flow based on the equation (3). . For example, if the ultrasonic frequency c is 2.
5 MHz, pulse repetition frequency pr of 5 KHz, sound velocity C of 154 m / sec, ultrasonic beam incident angle θ of 0 °,
Vmax = 0.77 m / sec when the blood flow rate scale is divided into positive and negative (4) (N = 4). Since the calculation result is input to the divider 34 of the numerical value calculation means 32, the divider 34 divides the maximum blood flow velocity Vmax by the number of divisions N, and the division result M is sent to the numerical value sequence output means 36 of the next stage. Send out. On the other hand, when aliasing has not occurred and the numerical value display switching key 38 is not pressed, the numerical value display switching key 38 outputs the "L" level display switching signal. Therefore, the coefficient selecting means 42 outputs "1" as the coefficient value k. Then, the multiplier 44 multiplies the division number N and the coefficient value k. In this case, since k = 1, the division number N remains unchanged.
Then, the value of the division number N is set in the counter 46. Therefore, from the counter 46, first, the value of the number of divisions N is directly given to the numerical sequence output means 36. The numerical value sequence output means 36 multiplies the division value M of the divider 34 and the value N from the counter 46, and outputs the positive or negative value of the multiplication value to the character code conversion circuit 48. When this positive / negative multiplication value is output, the value of the counter 46 is decremented by one, and the value of (N-1) is then given from the counter 46 to the numerical value sequence output means 36. In this way, the numerical sequence output means 36 sequentially outputs positive and negative values obtained by multiplying the divided value M by an integer. For example, in the above example, ± 0.
The value of the blood flow velocity is output as 77, ± 0.58, ...

The character code conversion circuit 48 uses the numerical sequence output means 36.
Each value from is converted into a character code, and this character code is stored in the character display memory 50.
In this case, the write address of the character code to the character display memory 50 is designated by the display address calculation means 52. Then, the image display memory 2
0 and data is read from the graphic display memory 26, in parallel with this, the character display memory 5
The character code is also read from 0, and after this character code is converted into a character signal by the display circuit 22,
It is output to the CRT 24. Therefore, on the display screen of the CRT 24, a power spectrum is displayed with the horizontal axis representing time and the vertical axis representing the magnitude of blood flow velocity, as shown in FIG. In this case, on the vertical axis, numerical values at the respective positions of the blood flow rate scale according to the number of divisions N are 0, 0.19, and 0, 0.19 from the center of the vertical axis.
The numbers are arranged so that positive numbers sequentially increase, such as 0.39, and so on, and the negative numbers sequentially decrease, such as 0, -0.19, -0.39, and so on, on the lower side. Is displayed.

That is, as shown in FIG. 3, when an observer who judges that aliasing has occurred presses the numerical display switching key 38, the numerical display switching key 38 outputs a display switching signal of "H" level. In response to this, the coefficient selecting means 42 outputs "2" as the coefficient value k. Then, the multiplier 44 multiplies the division number N and the coefficient value k. In this case, since k = 2, the output of the multiplier 44 is (2N). Then, the value of (2N) is set in the counter 46. Therefore, the value of (2N) is first given from the counter 46 to the numerical sequence output means 36 as it is. The numerical sequence output means 36 multiplies the division value M of the divider 34 and the value (2N) from the counter 46,
The positive / negative value of the multiplication value is used as the character code conversion circuit 4
Output to 8. When the positive / negative multiplication value is output from the numerical value sequence output means 36, the value of the counter 46 is decremented by one, and the counter 46 next gives the value of (2N-1) to the numerical value sequence output means 36. In this way, the numerical sequence output means 3
From 6, the positive and negative values obtained by multiplying the divided value M by an integer are sequentially output, but the range of the numerical sequence output in this case is in both positive and negative directions as compared with the case where the numerical display switching key 38 is not operated. It will be twice as large. That is, in the case of N = 4, ± 1.53, ± 0.9
6, ..., ± 0.77, ± 0.58, ..., The blood flow rate values are sequentially output.

Further, since the "H" level display switching signal from the numerical display switching key 38 is also given to the control circuit 8,
The control circuit 8 outputs a control signal for switching the numerical display to the display address calculation means 52. In response to this control signal, the display address calculation means 52 changes the write address of the data converted from the character code conversion circuit 48 into the character code and output. That is,
In FIG. 3, when aliasing occurs in the positive blood flow rate, the part where the aliasing occurs is displayed below the center of the vertical axis on the screen, and aliasing occurs in the negative blood flow rate. When it occurs, the part where aliasing occurs is displayed above the center of the vertical axis on the screen. Therefore, the numerical display of the blood flow velocity is also made to correspond to the part where aliasing occurs. For example, as shown by the numerical value in the third (), ± 1.53 to ± 0.77 of the expanded numerical value sequence.
For the range up to 1.5 from the center of the vertical axis to the lower side
3, 1.34, 1.15, ..., Positive numerical values are arranged and displayed so as to become smaller toward the lower side, and -1.53, -1. 34,
-1.15, ..., Negative numerical values are arranged and displayed so that the numerical values gradually increase toward the upper side. ±
The numerical value sequence of 0 to ± 0.77 is displayed as it is before the operation of the numerical value display switching key 38. The array display of each numerical value column is set by the address designation by the display address calculation means 52 when the character code is written in the character display memory 50.

In this way, when aliasing occurs, the doubled numerical value sequence is arranged on the blood flow rate scale. The size of the part can be read directly.

When displaying an ultrasonic tomographic image, the transmitting / receiving circuit 1
The echo signal from 0 is detected by the echo signal detection circuit 54, A / D converted by the A / D converter 56, and stored in the image display memory 20 as image data via the image selection circuit 18. Then, the image data read from the image display memory 20 is converted into a TV signal by the display circuit 22, and then output to the CRT 24.

(F) Effects As described above, according to the present invention, since the numerical values on the scale can be switched and displayed depending on the presence or absence of aliasing, it becomes possible to directly read the blood flow velocity value at the portion where aliasing occurs, etc. The excellent effect of is demonstrated.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory views showing a display example of a blood flow spectrum, and FIG. 2 shows no aliasing. In the case, FIG. 3 shows each state when the aliasing occurs. 1 ... Ultrasonic diagnostic device, 2 ... Setting means (setting key), 3
0 ... Maximum blood flow velocity calculation means, 32 ... Numerical value sequence calculation means,
38 ... Display switching means (numerical value display switching key), 4
0: Numerical value sequence expanding means, 52: Display address calculating means.

Claims (1)

[Scope of utility model registration request] 1. A setting means for setting respective values of a frequency of an ultrasonic beam pulse-emitted from a probe, a pulse repetition frequency, an incident angle of the ultrasonic beam with respect to a blood flow, and a division number of a blood flow rate scale. Maximum blood flow velocity calculating means for calculating the maximum blood flow velocity based on the value set by the setting means, the maximum blood flow velocity calculated by the maximum blood flow velocity calculating means, and the division set by the setting means. In an ultrasonic diagnostic apparatus equipped with a numerical value sequence calculation means for calculating a positive / negative numerical value sequence of the blood flow rate scale corresponding to the number of divisions based on the value of the number, a display switching means for switching the numerical value display of the blood flow rate scale In response to a display switching signal from the display switching means, a numerical value sequence expanding means for doubling the numerical value sequence range in both positive and negative directions, and a numerical value sequence enlarged by the numerical value sequence expanding means for blood flow velocity. Distribute on the scale Ultrasonic diagnostic apparatus characterized by comprising a display address calculating means for.