JPH03244444A - Ultrasonic doppler diagnostic device - Google Patents

Abstract

PURPOSE:To measure accurate rate of flow through computation with the section area of a flow path by computing the tangential speed from speed distribution of two reception signals having minute deflection angle difference, and using this tangential speed computed to the mentioned computation with the section area of flow path. CONSTITUTION:Transmission and reception of waves in sector scanning are made with two ultrasonic beams having a certain angle difference in the beam direction, and a tangential speed computing device 14 subjects two reflex signals to complex correlational computation, and on No.1 ultrasonic beam axis, the velocity component Vti in the sector scan arc tangential direction perpendicular to the beam axis is determined, and the mean tangential speed signal Vt=SIGMAVti/N is determined from the data number N thus obtained. A flow path section area setting device 16 sets the flow path section area Sc where a motion reflex body on the ultasonic beam axis exists, and the angle theta formed to the ultrasonic beam axis is set relation to the flow path by an angle setting device 18 and the section area signal corresponding to the section in question, and thus an angle signal sintheta corresponding to the current angle is obtained. A flow rate computing device 20 computes the tangential speed signal Vt and area S=Sc X sintheta obtained by multiplying the flow path section with the angle are computed from the above-mentioned tangential speed signal Vt, section area signal, and angle signal sintheta, thus accurate rate of flow Q=S X Vt is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is a medical ultrasonic Doppler diagnostic device, particularly for detecting blood flow in a moving reflector such as intracardiac blood flow or coronary artery blood flow inside a living body, The present invention relates to an ultrasonic Doppler diagnostic device that satisfactorily measures flow velocity, blood flow, etc.

[Prior Art] In the medical field, the ultrasonic pulsed Doppler method is used to measure the velocity of motion reflectors within a subject, such as organs such as the heart, blood flow in the circulatory system and blood vessels, body fluid flow, or the heart muscle. has been put into practical use, and this type of ultrasonic Doppler diagnostic equipment conventionally sends and receives ultrasound beams and detects moving reflectors based on the frequency shift of the reflected echo from the moving reflector within the subject. Detecting speed.

The velocity of the motion reflector is then displayed on the CRT screen in B mode or M mode display, making it possible to provide information useful for image diagnosis.

That is, for example, if an ultrasound beam with a constant repetition period is
The reflected wave from the moving reflector is received by the blood vessel inside the subject, and the velocity V of the moving reflector is measured based on this reflected wave, and the angle θ between the blood vessel and the ultrasound beam axis is measured. and the blood vessel radius r can be determined.

Then, the flow rate Q in the blood vessel is determined by calculation from the velocity V of these motion reflectors, the radius r of the blood vessel, and the angle θ.

Explanation of the basic principle of calculating the flow rate in the prior art, that is, the principle of the calculation method of the flow rate Q in a blood vessel is as follows: - As an example, when the cross section of the blood vessel is circular as shown in FIG. If the velocity component Vri in the ultrasound beam axis direction at a point, the angle θ formed between the blood vessel and the ultrasound beam axis, and the blood vessel radius r are given, the blood flow Q can be calculated using the following formula. .

That is, as shown in FIG. 7, if the velocity component Vri parallel to the beam axis direction at each point within the blood vessel and the average value of Vr within the blood vessel on the beam axis is <Vr>, it is expressed by the following equation.

<Vr>-(1/N)XΣVri-(1) However,
N is the number of data of the Vri.

Here, the flow velocity parallel to the blood vessel ■, and its average flow velocity <
V>, it is expressed as <V>-<Vr>/cosθ.

Therefore, the blood flow rate Q is expressed by the following equation.

Q-<V>XπX r2 -<V r >X (1/cosθ)×π×r2
... (2) Of course, in this equation (2), πX r 2 is the cross-sectional area of the blood vessel, and the velocity average value obtained by measuring N beam direction velocities Vri at each point on the cross section and dividing by the N values. The flow rate Q is determined by multiplying <Vr> by the πx r 2 .

As described above, with conventional ultrasound Doppler diagnostic equipment,
The blood flow Q is calculated by various calculation circuits based on the above equations (1) and (2), and thereby the blood flow is measured.

[Problems to be Solved by the Invention] However, in such conventional ultrasonic Doppler diagnostic devices, the blood flow can only be accurately measured using the equation (2) above at a flow velocity parallel to the blood vessel. There was a problem that it could not be measured.

That is, as shown in FIG. 7, if the equation (2) is satisfied,
The parallel flow velocity is determined as <Vr> If the angle θ- formed by the above <Vr> is (1/
Even if an attempt is made to find the velocity component of the flow parallel to the blood vessel by multiplying it by (cos θ), since the angle θ≠θ', there will be a flow rate error due to this angular difference, making it impossible to accurately measure the blood flow ff1Q. In the case of non-parallel flows in directions forming different angles θ', it was not possible to accurately determine the blood flow rate.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to obtain the tangential velocity and the cross section of the flow path such as the diameter of the blood vessel,
An object of the present invention is to provide an ultrasonic Doppler diagnostic device that accurately measures a flow rate by multiplying the tangential velocity and the cross-sectional area of the flow path.

[Means for Solving the Problems] In order to achieve the above object, according to the present invention, an ultrasonic beam with a fixed transmission repetition period is transmitted and received in a sector scanning manner in a flow path of a subject, and the reflected signal is received. In an ultrasonic Doppler diagnostic apparatus that detects the velocity of a motion reflector, the transmitted and received waves of the sector scanning are transmitted and received at a first beam direction having a predetermined angular difference in the beam direction.
, is carried out using a second ultrasonic beam, inputs a reflected signal in the first ultrasonic beam direction and a reflected signal in the second ultrasonic beam direction, calculates a complex correlation between both reflected signals, and performs a complex correlation calculation on the first ultrasonic beam. a tangential velocity calculator that calculates a velocity component Vti in the tangential direction of a sector scanning arc perpendicular to the beam axis on the ultrasound beam axis and outputs a tangential velocity signal Vt from this component; A flow path cross section setting device that sets a flow path cross section Sc in which a reflector exists and outputs a cross section signal corresponding to the cross section; and a flow path cross section setting device that sets an angle θ formed by the ultrasound beam axis with respect to the flow path. an angle setting device that outputs an angle signal sin θ corresponding to the angle, and the cross-sectional area signal and the angle signal si.
nθ, and calculates the area S-3cXs inθ multiplied by the flow path cross section and the angle and the tangential velocity signal Vt to obtain the flow rate g-sxvt.

Further, the tangential velocity calculator includes a delay device that inputs the reflected signal and outputs a delayed signal delayed by an integral multiple of a transmission repetition period, and multiplies the inputted reflected signal and the delayed signal. The flow path cross section setting device and the angle setting device each include a counter circuit.

Furthermore, the flow rate calculator includes an averaging circuit that inputs the tangential velocity signal Vt and the cross-sectional area signal, calculates an average value of tangential velocities on the beam axis, and outputs an average tangential velocity signal <Vt>; Input the channel cross-sectional signal and the angle signal sinθ, and calculate the cross-sectional area S=Sc in the direction in which the motion reflector moves.
Consisting of an area calculator that calculates ×sinθ and outputs an area value S, and a multiplier that calculates a flow rate value Q-8X<Vt> by multiplying this area value S and the tangential velocity signal <Vt>. It is characterized by being

[Operations] With the above-described configuration, the ultrasonic Doppler diagnostic apparatus of the present invention transmits and receives an ultrasound beam with a constant transmission repetition period to and from the flow path of the subject by sector scanning. receive the reflected signal.

This reflected reception signal is obtained by transmitting and receiving waves in sector scanning, which are a reflected signal in the first ultrasonic beam direction and a reflected signal in the second ultrasonic beam direction, which have a predetermined angular difference in the beam direction.

Therefore, by performing a complex correlation calculation on both reflected signals, a velocity component Vti in the sector scanning arc tangential direction perpendicular to the beam axis is obtained on the first ultrasound beam axis, and this V
From the data number N of ti, the average tangential velocity signal <Vt> - ΣV
ti/N can be found.

Here, the angle formed by the channel cross section and the beam axis is set in advance, and a cross-sectional area signal Sc corresponding to the channel section R where the motion reflector exists on the ultrasonic beam axis or the radius r of the channel
−πX (R/2) 2 or π×(r/siHθ)2 and an angle signal sin θ corresponding to the angle θ formed by the ultrasound beam axis with respect to the flow path can be obtained.

As a result, the tangential velocity signal <Vt>, the cross-sectional area signal, and the angle signal sinθ are input, and the area S−ScXsinθ, which is the product of the channel cross section and the angle, and the tangential velocity signal <Vt> are calculated. Then, the flow rate Q-8X<Vt>, that is, the flow rate Q-<Vt>×πX (R/2) 2xsi
nθ or <vt >XπX (r/s i nθ)2
It becomes possible to find.

Accordingly, the present invention calculates the average tangential velocity based on the tangential velocity component perpendicular to the ultrasound beam axis, and easily calculates the flow rate in the flow path cross section of the motion reflector without being influenced by the direction of the flow velocity. This makes it possible to measure quickly and with high precision.

[Example] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic Doppler diagnostic apparatus according to the present invention.

A characteristic feature of the present invention is that a tangential velocity component perpendicular to the ultrasound beam direction is determined, and the flow rate is determined from this velocity component and the region where the motion reflector is present on the ultrasound beam axis.

The basic principle of the present invention will be explained below using mathematical formulas based on the principle diagram of the present invention shown in FIG.

Note that explanations of the same symbols and formulas as in the conventional example shown in FIG. 7 will be omitted.

As shown in FIG. 6, the tangential velocity V at each point in the blood vessel
t t, the length that the ultrasound beam crosses the blood vessel is R1, the radius of the blood vessel is r, the average flow velocity parallel to the blood vessel is <V>, and the flow path cross section Sc, then the blood flow Q is calculated as follows: Become.

(Blood flow) Q-<v>XffXr2 - (3) Here, the blood vessel radius r is r= (R/2)Xs inθ, so the blood flow Q is Q-<V>xπx ((R /2) X sinθ
)2... (4) Here, the average value of tangential velocity <Vt> has a relationship with the average value of flow velocity parallel to the blood vessel <V> as shown in the following equation.

<vt>-<V>Xs inθ - (5) Therefore, from the above equation (5), the above equation (4)
scxs inθ − (5°)Q−<Vt>Xπ
X (R/2) 2X5 inθ... (6)

Note that <vt> is based on the above formula (1),
>−(1/N)X): Vt i −·−(7).

Therefore, by calculating the above equation (4), the blood flow rate Q in the blood vessel can be accurately determined without correcting the direction of the blood flow.

Here, the above equation (6) is expressed by the length R of the ultrasonic beam across the blood vessel, but if expressed by the blood vessel radius r, then R-D is expressed as
D/2Xsinθ-r Therefore, D-2r/sinθ, which can be converted to the above (6)
Substituting into the formula, we get the following formula.

Q-<vt>xscxs inθ-<Vt>XπX (D/2) 2Xs inθ-<
vt )xπx (r/s inθ)2Xsinθ・
... (8) becomes.

As described above, according to this principle, the flow rate Q can be easily obtained, and in the case of pulsatile flow in the heart, for example, the flow rate can be integrated between the R waves of the electrocardiogram and the time of the R waves. This makes it possible to determine the cardiac output.

To explain the specific circuit configuration and operation of this embodiment, based on the basic principle of this embodiment described above, the schematic configuration and operation of FIG. This will be explained in detail using

In FIG. 1, the ultrasound Doppler diagnostic apparatus of this embodiment is as follows:
Main circuits include a transmitting/receiving section 10, a radial velocity computing section 12, a tangential velocity computing section 14, a channel cross section setting device 16, an angle setting device 18, and a flow rate computing device 20, which are characteristic of the present invention. .

That is, the transceiver 10A that generates a stable high frequency signal from the transmitter/receiver section 10 outputs the high frequency signal by sector scanning via a scan controller (not shown).

As is well known, a transmission frequency signal (3 MHz) 10a of an ultrasonic pulse wave for transmission is output to the probe 10. As a result, the probe 10B transmits an ultrasound beam with a constant transmission repetition period, for example, multiple times, and the reflected signal 10b from within the subject 11 is received by the transducer 10A via the probe IOB.

Thereby, the reflected wave from the desired test site due to the well-known Doppler effect is converted into an electrical signal via the probe IOB and received by the transceiver 10A.

Specifically, if an ultrasonic beam is emitted as shown in Figure 6.7, at each point on the beam axis, for example, a,
Reflected waves in the first ultrasonic beam direction of b, c, .

In this case, if the ultrasonic pulse wave is emitted multiple times, a 1
．． a2. -=---, b 1. b2.・−
A received signal of =-, c IC2, . . . is obtained.

Then, the beam direction is changed by a minute deflection angle Δθ and the beam is emitted, and the beam direction corresponding to each point, for example, a−, b″, C
, . . . reflected waves in the second ultrasonic beam direction are obtained.

As a result, the transmitter/receiver 10 outputs the first and second received signals (reflected waves), and these received signals are input to the radial velocity calculator 12 .

That is, the radial velocity calculating section 12 inputs each of the received signals as shown in FIG. 1, and calculates velocity components for each point, for example, Va, Vb, and Vc.

...and Va-, Vb-, Vc-, ...
This is a circuit for calculating .

The radial velocity calculation unit 12 includes a complex signal converter 12A that inputs the reflected signal and outputs two complex signals having a complex relationship, and a complex signal converter 12A that inputs the complex signal and delays the complex signal for a predetermined time. A complex delay canceller 12B calculates the delayed signal and the complex signal, removes clutter components, and outputs the calculated signal, and inputs the calculated signal, calculates autocorrelation, and outputs a velocity signal corresponding to the Doppler frequency shift. 12C.

That is, in order to detect the Doppler shift frequency, which is velocity information, the radial velocity calculation unit 12 of this embodiment converts the received signal into a complex signal, and performs an autocorrelation calculation based on this complex signal. ing.

Speed calculations are performed using each of these circuit configurations, but
This speed calculation means was developed by the applicant in Japanese Patent Publication No. 62-44.
This method is described in detail in Japanese Patent No. 494 as a complex autocorrelation method.

Here, the complex signal converter 12A converts two signals having a complex relationship, for example, a real part signal R and an imaginary part signal I, and outputs them as a complex signal Z-R+i1.

These complex signals are then supplied to the complex delay canceller 12B in order to remove clutter components from, for example, a stationary reflector or a slow-moving reflector within the subject, where they are combined with the current complex signal and, for example, The difference between one period of the signal is calculated by successively comparing the delayed signal one period before the delay time that corresponds to one period of the transmitted repeated signal at the same depth, and as a result, the difference output of the difference calculation result is approximately It becomes close to zero, and clutter components can be suppressed.

As described above, the complex signal from which only the clutter component has been removed is input to the first autocorrelator 12C as a speed calculator and subjected to speed calculation. The complex signal of the reflected signal is subjected to an autocorrelation operation, and thereby the complex product or conjugate product of the complex signal is obtained.

Therefore, the autocorrelation signal Zs, which is a complex signal, is Zs■R
It is output as s+i1g.

Since this autocorrelation signal S includes signal fluctuation components and noise components generated from the device itself, it is averaged by an averaging circuit (not shown) to remove these noise components, and is expressed as Zs=Rs+i I s. and complex correlation is calculated.

Then, by this autocorrelation calculation, the velocity of the reflected signal with respect to the first ultrasonic beam is computed, and a velocity signal is output from the radial velocity computing unit 12 and input to the tangential velocity computing unit 14 at the next stage. .

Incidentally, such processing of the radial velocity calculation section 12 is described in detail in Japanese Patent Application Laid-Open No. 152436/1983 by the present applicant.

Description of tangential velocity computing unit The tangential velocity computing unit 14 to which the velocity signal is input,
As shown in FIG. 2, two delay devices 14A.

14B and four multipliers 14C, 14D, 14E.

14F, a second autocorrelator 14' consisting of two adders 14G and 14H, an arctangent operator 141, and an argument multiplier 14
It is composed of J.

That is, the tangential velocity calculation unit 14 compares the velocities of two received signals with a slight difference in deflection angle, and calculates the difference in velocity at the same distance, that is, the tangential velocity in the direction perpendicular to the ultrasound beam axis.

Particularly, this tangential velocity calculating section 14 constitutes a second autocorrelator 14' from the delay device, multiplier, and adder.

This second autocorrelator 14' is the same as the first autocorrelator 12C described above, and more specifically, the second autocorrelator 14' is a complex signal consisting of a real part R and an imaginary part I. The velocity of the reflected signal with respect to the second ultrasound beam is calculated.

As a result, the input complex signal is transmitted to the delay device 1.
4A and 14B, the delay signal is delayed by an integral multiple of the transmission repetition period, for example, by one period, and based on the complex signal with a difference of one period, 4
After multiplying the reflected signal and the delayed signal using the three multipliers 14C, 14D, 14E, and 14F, the adder 14G, and the adder (subtraction) 14H, an addition operation is performed to perform an autocorrelation operation. will be held.

As a result, the adders 14G and 14H output the autocorrelation signal Zs, which is a complex signal, that is, Zs-Rs+iI
s is output and further averaged as described above to obtain Rs and Is.

The tangential velocity calculator 14 compares the first autocorrelation signal and the second autocorrelation signal to perform a complex correlation calculation. This is performed, for example, by conjugate product calculation, and thereby a signal of the tangential velocity component can be obtained.

Next, these autocorrelation signals Rs and Is are calculated by the arctangent calculator 141 to calculate the angle, that is, the argument a
mt an-'' (I s/Rs) is determined. The argument α of this autocorrelation signal corresponds to the frequency shift of the Doppler signal subjected to the Doppler effect, and based on this, the tangential velocity signal is determined.

Further, in this tangential velocity calculation unit 14, the argument angle α is multiplied by the negative value of the reciprocal of the minute scanning angle Δθ, −1/KXΔθ, by the argument angle multiplier 14J (where K is a constant), thereby, As mentioned above, the velocity due to the first ultrasonic beam and the second
The tangential velocity Vti with respect to the velocity due to the ultrasonic beam is determined.

Of course, this calculation is performed on the velocity components at each point on the beam axis, and the minute deflection angle Δθ is sequentially calculated by 2Δθ
, 3Δθ, .

As described above, Vt1-VXsin θ is obtained, which represents the tangential velocity, and this Vti becomes the output signal of the tangential velocity calculation section 14.

A detailed explanation of the configuration of the tangential velocity calculator 14 is disclosed in Japanese Patent Application No. 1982-292 by the present applicant.
It is described in detail in Japanese Patent No. 112.

Explanation of the flow path cross section setting device and angle setting device On the other hand, the flow path cross section where the motion reflector exists, for example, the area where blood flow exists in the blood vessel, and the angle formed by the ultrasound beam axis with respect to the flow path are set. The flow path cross section setter 16 and the angle setter 18 are shown in FIG.

Settings of these fixed setting devices are controlled by using, for example, a trackball or a joystick.

That is, as shown in FIG. 4, the flow path cross-section setting device 16 receives a pulse signal 16a having a time width corresponding to the flow setting area, and counts the input signal of the time width by a counter circuit 16A. A channel cross section signal 16b corresponding to the counting result is output.

This is expressed by the length R of the beam across the blood vessel shown in equation (6) or equation (8) above, or π x (R/2)2, or the radius r of the blood vessel, expressed by π x (r/s This corresponds to the channel cross section Sc of i nθ)2.

The angle setter 18 also outputs a pulse signal 1 having a time width corresponding to the magnitude of the set angle θ, as shown in FIG.
8a is input, the counter circuit 18A counts the large-width signal of the time, and outputs the output signal (
Angle signal) 18b will be output (signal of sin θ).

In this way, the predetermined channel cross section Sc and angle θ are set.

Explanation of the flow rate calculator Next, FIG. 3 shows the averaging circuit 2OA and the area calculator 20.
The flow rate calculator 20 is shown, which is made up of a multiplier 20C and a multiplier 20C.The flow rate calculator 20 receives the tangential velocity signal Vti, the channel cross section signal 16b, and the angle signal 18b, and calculates the The flow rate Q is calculated.

That is, first, the averaging circuit 2OA inputs the tangential velocity Vti and the channel cross-sectional signal 16b, and calculates the average value <Vt>-ΣVt i/N of the tangential velocity in the blood vessel ((7) above). formula).

On the other hand, the area calculator 20B inputs the channel cross-sectional signal 16b and the angle signal 18b, and calculates the channel cross-sectional area S-8cxsinθ on the ultrasound beam axis of the blood vessel.

Specifically, as shown in Figure 3, (6
) The cross-sectional area of the flow path at the length R that the beam crosses the blood vessel is S = (R/2) 2xπX5inθ, or (8)
5-(r/sinθ) 2×π at the blood vessel radius r in the equation
It is determined by Xs in θ.

Therefore, from the above results, the average value of the tangential velocity <Vt> is multiplied by the flow path cross-sectional area S by the multiplier 20C according to the basic formula for the flow rate Q of equation (5-), and the multiplication result is A flow rate Q-<Vt>xScxs inθ is calculated, and a flow rate calculation signal 20b is output.

This corresponds to, for example, Q-<vt>XπX (D/2) 2xs inθ shown in equation (8) above.

In this way, the flow rate calculation signal 20b obtained by calculating the flow rate information is transmitted to the DSC 22 and the DSC shown in FIG.
The signal is outputted via the /A converter 24 to a CRT 26 or the like serving as a display.

In this DSC (digital scan converter) 22,
Echo signals for B-mode image display are written,
For example, the CRT 26 may be connected to the CRT 26 via the D/A converter 24.
The reflected reception signal is read out at a sweep period of a display device or the like.

As a result, the brightness-modulated B-mode display is displayed two-dimensionally as a tomographic image on the display device, and the flow rate information is displayed in an image distribution overlaid on, for example, the B-mode tomographic image.

As described above, according to the embodiment of the present invention, the tangential velocity can be calculated even in the case of blood flow having not only a velocity component of a flow parallel to a blood vessel but also an angle θ' formed by a non-parallel flow. It is possible to easily measure the flow rate with high accuracy by calculating the cross-sectional area of the flow path.

Furthermore, according to this embodiment, in addition to diagnostic information from conventional ultrasound diagnostic equipment, accurate flow rate and its distribution can be displayed as images at the same time as blood flow velocity and blood flow velocity distribution, making it possible to display images of accurate flow rate and its distribution. In addition, it is possible to obtain an ultrasonic diagnostic apparatus that can provide an extremely large amount of diagnostic information.

In addition, according to this embodiment, although an example was given regarding blood flow, it is of course possible to apply to urine or other body fluids as well.

[Effects of the Invention] As described above, according to the ultrasonic Doppler diagnostic apparatus according to the present invention, the tangential velocity is calculated from the velocity distribution of two received signals having a minute deflection angle difference, and the tangential velocity is calculated based on the tangential velocity. The flow rate can be determined by calculation with the cross-sectional area of the flow path.

As a result, even if the movement direction of the motion reflector is, for example, a velocity component in an oblique direction rather than a velocity component parallel to the blood vessel, an accurate blood flow rate can be calculated by determining the tangential velocity.

Therefore, it is possible to accurately and easily determine intracardiac blood flow and coronary artery blood flow regardless of the direction of blood flow, and to visualize it on an image.

Further, according to the present invention, since a conventional tangential velocity calculator is used, the flow rate can be determined simply by applying an area calculator, which has the advantage of simplifying the circuit configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an ultrasonic Doppler diagnostic device according to the present invention, FIG. 2 is a block diagram showing a circuit configuration of a tangential velocity calculator, and FIG. 3 is a circuit diagram of a flow rate calculator. 4 is a block diagram showing the relationship between the input and output signals of the flow path cross-section setting device. FIG. 5 is a block diagram showing the relationship between the input and output signals of the angle setting device. The figure is a diagram showing the principle of calculating flow rate using tangential velocity and area according to the present invention, and FIG. 7 is a diagram showing the principle of calculating flow rate using the conventional method. Vri ... Velocity component in the beam axis direction at the intravascular point ■ ... Flow velocity parallel to the blood vessel <V> ... Average velocity of the flow velocity parallel to the blood vessel θ ・
... Angle R between the blood vessel and the beam axis ... Length r that the beam crosses the blood vessel ... Radius of the blood vessel N ... Number of data for Vri Vt ... Tangential velocity <Vt> ... Tangential velocity The average value Sc...
Channel cross section Q...Blood flow rate 12...Radial velocity calculation unit 14...Tangential velocity calculation units 14A, B...Delay units 14C, D, E, F...Multiplier 14G
, H... Adder 141... Arctangent calculator 14J... Argument angle multiplier 16... Channel cross section setter 16A, 18A... Counter circuit 18...
Angle setting device 20... Flow rate calculator 2OA... Averaging circuit 20B... Area calculator 20C... Multiplier.

Claims (3)

[Claims] (1) In an ultrasonic Doppler diagnostic device that transmits and receives an ultrasound beam with a fixed transmission repetition period in a sector scanning manner in a flow path of a subject, and detects the velocity of a moving reflector by receiving the reflected signal, the sector Transmission and reception of scanning is performed using first and second ultrasonic beams having a predetermined angular difference in the beam directions, and a reflected signal in the first ultrasonic beam direction and a reflected signal in the second ultrasonic beam direction. is input, complex correlation calculation is performed on both reflected signals to obtain a velocity component Vti in the tangential direction of the sector scanning arc perpendicular to the beam axis on the first ultrasound beam axis, and from this component, a tangential velocity signal Vt is obtained. a tangential velocity calculator that outputs a tangential velocity calculator; a flow path cross section setting device that sets a flow path cross section Sc where the motion reflector exists on the ultrasound beam axis and outputs a cross section signal corresponding to the cross section; an angle setting device that sets an angle θ formed by the ultrasound beam axis with respect to the flow path and outputs an angle signal sin θ corresponding to the set angle; Area S = Sc x sin θ multiplied by the cross section and the above angle
and a flow rate calculator which calculates the flow rate Q=S×Vt by calculating the tangential velocity signal Vt and the tangential velocity signal Vt, based on the tangential velocity component perpendicular to the ultrasound beam axis by the tangential velocity calculator, An ultrasonic Doppler diagnostic device characterized by determining the flow rate in a cross section of a body channel. (2) In the device according to claim (1), the tangential velocity calculator has a delay device that inputs the reflected signal and outputs a delayed signal delayed by an integral multiple of the transmission repetition period. The channel cross section setting device and the angle setting device each include a counter circuit. Ultrasonic Doppler diagnostic equipment. (3) In the apparatus according to claim (1) or (2), the flow rate calculator inputs the tangential velocity signal Vt and the cross-sectional area signal, and calculates the average value of the tangential velocity on the beam axis. An averaging circuit that outputs an average tangential velocity signal <Vt>, the channel cross-sectional signal and the angle signal sinθ are input, and the cross-sectional area S=S in the direction of movement of the motion reflector is inputted.
An area calculator that calculates c×sinθ and outputs an area value S, and a multiplier that calculates a flow rate value Q=S×<Vt> by multiplying this area value S by the tangential velocity signal <Vt>. An ultrasonic Doppler diagnostic device comprising: