JPH04126137A - Ultrasonic doppler diagnostic device - Google Patents

Abstract

PURPOSE:To quickly derive the three-dimensional velocity vector of a motion reflecting body with high accuracy by setting two receiving beams against a transmitting beam in each scanning face, and calculating a velocity component at every receiving beam. CONSTITUTION:The scanning face 10 is formed, for instance, by scanning electronically an array vibrator in which plural vibration elements are arrayed. Also, in this scanning face 10, two receiving beams 102, 104 for intersecting from each different direction are set against a transmitting beam 100. Moreover, an angle of a two-dimensional velocity vector U against the transmitting beam 100 is shown by theta, and on the other hand, an angle of each receiving beam 102, 104 against the transmitting beam 100 is shown by phi. This angle phi is derived by an expression I. Also, a velocity component UR running along the receiving beam 102 and a velocity component UL running along the receiving beam 104 are shown by an expression II. In this regard, U denotes and absolute value of the velocity vector U.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic Doppler diagnostic apparatus, and particularly to an ultrasonic Doppler diagnostic apparatus that measures the three-dimensional velocity of a motion reflector such as blood flow within a subject.

[Prior Art] Conventionally, moving parts within a subject, such as organs such as the heart,
In order to measure the velocity of motion reflectors such as blood flow and body fluid flow in the circulatory system and blood vessels, an ultrasonic Doppler diagnostic device using the ultrasonic pulse Doppler method is used.

This ultrasonic Doppler diagnostic device transmits ultrasonic pulses into the subject at a constant repetition rate and analyzes the Doppler shift frequency of the reflected waves from the moving reflectors within the subject. I'm looking for speed.

For measuring the two-dimensional distribution of the frequency shift (Doppler shift) of reflected waves in such an ultrasonic Doppler diagnostic apparatus, an autocorrelation method is used, for example, as disclosed in Japanese Patent Publication No. 62-44494.

By the way, as an apparatus for determining the three-dimensional velocity vector of a motion reflector within a subject, for example, Japanese Patent Application No. 1-341197
The device proposed in No.

In this device, the velocity components (two-dimensional velocity vectors) of the motion reflector on two scanning planes whose scanning directions differ by a predetermined angle are determined, and the three-dimensional I am looking for the original velocity vector.

As a method for determining the two-dimensional velocity vector in each scanning plane, there is, for example, the method described in Japanese Patent Laid-Open No. 152436/1983.

In this method, a sector scanning type ultrasound probe first transmits and receives waves in a first ultrasound beam direction, and then transmits and receives waves in the first ultrasound beam direction.
Waves are transmitted and received in a second ultrasonic beam direction that differs by a small angle from the direction of the ultrasonic beam, and from the two received signals obtained by these transmitted and received waves, the velocity component of the motion reflector along the ultrasound beam ( From these two radial velocities, calculate the velocity component in the tangential direction perpendicular to the radial direction (tangential velocity), and from the radial velocity and tangential velocity obtained above. Velocity component in the scanning plane of the ultrasonic beam of the motion reflector (two-dimensional velocity vector)
This is what we seek.

Therefore, as mentioned above, by setting two scanning planes in which the scanning directions of the ultrasonic beam differ by a predetermined angle, and finding the two-dimensional velocity vector of the motion reflector in each scanning plane using the above method, it is possible to obtain From the two two-dimensional velocity vectors, the velocity component perpendicular to the scanning plane can be determined by vector calculation, and it is also possible to calculate the three-dimensional velocity vector of the motion reflector.

[Problems to be Solved by the Invention] However, the above-mentioned conventional ultrasound Doppler diagnostic apparatus for determining a three-dimensional velocity vector has the following two problems.

The first problem is that when determining the two-dimensional velocity vector, the radial velocity of the motion reflector is determined using two ultrasonic beams radially with the ultrasonic probe as the apex at slightly different angles. The problem is that the data acquisition positions are different, making it impossible to determine the velocity component in the radial direction at the same position.

The second problem is that the two velocity components cannot be determined simultaneously from the time difference required for scanning the two ultrasonic beams within the scanning plane.

Therefore, due to the above two problems, the accuracy of the three-dimensional velocity vector of the motion reflector deteriorates, and the three-dimensional velocity vector cannot be measured quickly.

The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to have two
To provide an ultrasonic Doppler diagnostic device that can quickly and accurately determine the three-dimensional velocity vector of a motion reflector by setting two receiving beams and calculating the velocity component for each receiving beam. be.

[Means for Solving the Problems] In order to achieve the above object, an ultrasound Doppler diagnostic device according to the present invention transmits and receives ultrasound within a first scanning plane formed by scanning an ultrasound beam. and a first wave transmitting/receiving/velocity calculation means for calculating a first two-dimensional velocity vector on the first scanning plane of the motion reflector from the received wave signal, and a scanning direction different from the first scanning plane by a predetermined angle. Transmit and receive ultrasonic waves within a second scanning plane, and from the received signal, the second
a second wave transmitting/receiving/velocity calculation means for calculating a second two-dimensional velocity vector in a scanning plane; and a three-dimensional velocity calculating means for calculating a three-dimensional velocity vector of the motion reflector from the first and second two-dimensional velocity vectors. vector calculation means, and the first and second wave transmission/reception/velocity calculation means are arranged to intersect the transmission beam from two different directions in the scanning plane.
a wave transmitting/receiving section configured to receive the reflected waves from the moving reflector in the two specific directions simultaneously; two velocity calculation units that calculate velocity components along the received beams of the motion reflector from the signals; and an intersection angle between the two velocity components found by the two velocity calculation units and the two received beams. A two-dimensional velocity vector calculation unit that calculates a two-dimensional velocity vector of the motion reflector in the scanning plane from the following.

[Function] According to the above configuration, in the first and second scanning planes, two receiving beams that intersect with the transmitting beam are set,
It is possible to simultaneously receive the reflected waves from the motion reflector in two different directions, and it is also possible to process these two received signals in parallel by the two velocity calculation units. In other words,
It becomes possible to simultaneously obtain two velocity components using these two velocity calculation units.

Then, based on the two radial velocities determined by the two velocity calculation units, the two-dimensional velocity vectors of the motion reflector in each scanning plane are determined, and the motion reflector is further determined by the three-dimensional vector calculation means. The three-dimensional velocity vector of

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

First, the measurement principle of the present invention will be explained using FIGS. 1 and 2.

Here, FIG. 1 shows the principle of obtaining a two-dimensional velocity vector, and FIG. 2 shows the principle of obtaining a three-dimensional velocity vector.

In FIG. 1, the three-dimensional velocity vector of the motion reflector Q is indicated by V, and the projection of this three-dimensional velocity vector V onto the scanning plane 10 is the two-dimensional velocity vector indicated by a broken line in the figure. It is.

The scanning surface 10 is formed, for example, by electronically scanning (for example, sector scanning) an array vibrator in which a plurality of vibrating elements are arranged.

In this scanning plane 10, two receiving beams 102 and '104 are set which intersect with the transmitting beam 100 directed in the Z-axis direction in the figure from different directions. That is, the reflected wave from the moving reflector Q located at a predetermined distance in the transmission beam 100 is received at a position separated from the origin O by a predetermined distance a in the Y-axis direction.

The velocity components of the two-dimensional velocity vector σ in the scanning plane 10 along each receiving beam 102 and 104 are indicated by UR and UL, respectively, in the figure.

In addition, the two-dimensional velocity vector “
The angle of is indicated as θ in the figure, while the transmit beam 10
The angle of each received beam 102, 104 with respect to zero is designated φ.

This angle φ can be determined using the first equation below.

φ-tan' (a/L) -(1)
The velocity component UR along the receiving beam 102 and the velocity component U along the receiving beam 104 are expressed by the following equation.

U,, −Ucos (θ ten φ) −
(2) UR-Ucos (θ-φ)
-(3) Here, U is the absolute value of the velocity vector σ.

From the second and third equations obtained above, the following fourth and fifth equations can be derived.

U R+ U t, -2U cosθcosφ
・(4) UR-UL-2Us1nθs1nφ
-(5) Therefore, the Y-axis and Z-axis components UY of the two-dimensional velocity vector on the scanning plane 10 on the YZ plane
, Uz can be determined as follows.

UY-Usinθ-(URU L) / 2 sin
φ... (6) Uz-UcosO-(UR+UL)/2
eosφ... (7) Here, UR, U in the sixth and seventh equations.

can be determined from the respective received signals in the received beams 102 and 104 using the Doppler method, and since the angle φ is a known value obtained from the first equation, from the above equations 6 and 7, , it is possible to obtain the velocity components of the two-dimensional velocity vectors and the scanning plane 10, respectively.

Note that the magnitude and angle θ of the two-dimensional velocity vector can be determined from the following equations 8 and 9.

θwmtan (UY/Uz) = tan ((UU) / (UR1UL)L tanφ) ... (8)
U-(U +U 21 ”'...(
9) Z In this way, by setting the two receiving beams 102 and 104 that intersect with the transmitting beam 100, two velocity components in the scanning plane 10 of the two-dimensional velocity vector can be obtained in one transmission. Is possible.

Note that in the above explanation, it is assumed that the moving reflector Q is on two axes for the sake of simplicity. It is possible to find the velocity component of the dimensional velocity vector ".

Next, a method for determining the three-dimensional velocity vector V will be explained using FIG. Note that the following method for determining a three-dimensional velocity vector from this two-dimensional velocity vector is the same as that described in the conventional example.

FIG. 2 shows a first scanning surface 11 extending in the Y-Z direction, and a second scanning surface 12 ( (indicated by a dashed line in the figure).

As shown in FIG. 1, the three-dimensional velocity vector V projected onto the first scanning plane 11 is the two-dimensional velocity vector V, while the one projected onto the second scanning plane 12 is the two-dimensional velocity vector V. vector σ′.

The two-dimensional velocity vector in the first scanning plane is a unit vector in the XYz rectangular coordinate system, respectively, σ8. σ7.
σ2 is expressed by the following equation 10.

ff-UYσ, 10U2σ7...(10)
On the other hand, the three-dimensional velocity vector V is the sum of the two-dimensional velocity vector σ expressed by the above equation 10 and the component UX perpendicular to the first scanning plane 11, and is expressed as the following equation .

v-bi+uXe, -(11)
Next, the first scanning plane 11 is rotated by an angle of y--
Consider a second scanning plane 12 extending in the z'' plane.

The two-dimensional velocity vector “′” on this second scanning plane 12
As explained using FIG. 1, the velocity component U-U- along the receiving beam is R'L. Expressed by the formula.

U −-(U −U −L ) / 2slnφ−(1
2) Y R U= −(U−+U″L)/2cosφ...(13
) Z R On the other hand, the three-dimensional velocity vector V is expressed in two coordinate systems as (UUU) and (U=, respectively).

X'Y'ZU-y, U-z), the following relationships exist between these components.

U x-U -X cosβ-U -YsinIJ
−U″X slnβ 0U″YcosUz″″Uz By calculating U−X from the 15th equation and doing the same, the following m17 equation is obtained.

β ... (14) β ... (15) ... (16) Substitute into equation 4 U - (UY-U-y eO8β) /lanβ-U
Y sin β −(
17) In this 17th equation, Uy and U −y are
As mentioned above, the above 6th and 12th equations are obtained using the Doppler method.
Since the angle β is a set angle and is known, Ux can be found from the above equation 17.

Therefore, the three-dimensional velocity vector V can be determined as (UX, U, , U2) as velocity components in the XYZ orthogonal coordinate system.

The magnitude of the three-dimensional velocity vector V and the angle γ that the vector makes with the first scanning plane 11 can be determined from the following equations 18 and 19.

(19) As described above, the first scanning plane 11 and the second scanning plane 12
The three-dimensional velocity vector V of the motion reflector can be determined from the two-dimensional velocity vector V and '', and it becomes possible to understand the blood flow velocity in the living body and the movement of living tissues in a three-dimensional manner. .

Next, the configuration of the ultrasonic Doppler diagnostic apparatus according to the present invention to which the above principle is applied will be explained using FIG.

FIG. 3 shows the first part of the ultrasound Doppler diagnostic apparatus according to the present invention.
An example is shown.

In FIG. 3, the ultrasonic probe 20 includes an array transducer in which a plurality of transducer elements are arranged, and a rotation mechanism for rotating the array transducer. It is something that forms.

This ultrasonic probe 20 is supplied with a predetermined transmission pulse signal from a transmitter 22, and the ultrasonic probe 20
A predetermined rotation control signal is supplied from the rotation control section 24 to the rotation mechanism at 0.

In the figure, the scan control section 26 is the timing signal generation section 2
8, and based on this signal, the ultrasonic probe 20
It controls the transmission and reception of waves and the scanning of ultrasonic beams.

As explained using FIG. 1, the ultrasonic probe 2
0 transmission/reception, two reception beams are set, and two reception signals SR related to these two reception beams are set.
, SL are each sent to the scanning plane vector analysis section 18. Here, the scanning plane vector analysis section 18 is composed of two reception sections 30.degree. 32, two velocity calculation sections 34 and 36, and a two-dimensional velocity vector calculation section 38.

The received signals SR and SL are sent to two receiving sections 30 and 32 provided in the scanning plane vector analysis section 18, respectively. Here, the receiving sections 30, 32 are composed of amplifiers, quadrature detectors, etc., and their output signals are sent to speed calculating sections 34 and 36, respectively. In addition, the receiving section 3
0.32, a predetermined reference wave signal for performing orthogonal detection is supplied from the scanning control section 26 in addition to the phase control signal of the received signal.

The speed calculating sections 34 and 36 calculate Doppler information along each receiving beam, that is, the speed component of the moving reflector, from the input received signal by using an autocorrelation method or the like.

The determined velocity components UR, U along the two receiving beams are input to the two-dimensional velocity vector calculation unit 38.

The two-dimensional velocity vector calculation unit 38 uses the input velocity component UR1Ut and information on the angle φ supplied from the scan control unit 26 to calculate the component (U
, , U2) are calculated based on the above-mentioned formulas 6 and 7.

Information on the magnitude of the two-dimensional velocity vector and information on the angle θ obtained by the two-dimensional velocity vector computing unit 38 are sent to the three-dimensional velocity vector computing unit 40.

The three-dimensional velocity vector calculation unit 40 calculates the three-dimensional velocity vector of the motion reflector from the respective two-dimensional velocity vectors in the first scanning plane and the second scanning plane, as explained using FIG. It is something to seek.

Note that in this example, data is acquired on the second scanning plane after data is acquired on the first scanning plane, so the information on the two-dimensional velocity vector on the first scanning plane is , is temporarily stored in the three-dimensional velocity vector calculation unit 40, and when the two-dimensional velocity vector information on the second scanning plane is obtained, a three-dimensional velocity vector is calculated from the two two-dimensional velocity vector information. are doing.

Then, the information on the size of the three-dimensional velocity vector V and the information on the angle γ obtained by the three-dimensional velocity vector calculation unit 40 are sent to a digital scan converter (D, S, C).
The data is sent out to the computer, temporarily stored, read out using a predetermined readout signal, and displayed on the display section 44.

Next, a second embodiment of the ultrasonic Doppler diagnostic apparatus according to the present invention will be described. FIG. 4 shows a second embodiment of the ultrasonic Doppler diagnostic apparatus according to the present invention. In this embodiment, two-dimensional In order to obtain the velocity vector, two systems of scanning plane vector analysis sections 18 shown in FIG. 3 are provided.

That is, in the ultrasonic probe 20, the first scanning plane and the second scanning plane are formed simultaneously, and it is possible to obtain information on two two-dimensional velocity vectors at once.
The two received signals on the scanning plane are sent to the first scanning plane vector analysis section 50, while the two reception signals on the second scanning plane are sent to the second scanning plane vector analysis section 52.

Here, the first and second scanning plane vector analysis units 50.52
has almost the same configuration as the two-dimensional velocity vector analysis section shown in FIG.

That is, each vector analysis section 50.52 has two receiving sections, two velocity calculating sections corresponding to these two receiving sections, and information on velocity components along the received beam from these two speed calculating sections. and a two-dimensional velocity vector calculation unit that receives input and calculates a two-dimensional velocity vector.

and first and second scanning plane vector analysis units 50.52;
The two-dimensional velocity vector information from the two-dimensional velocity vectors is input to the three-dimensional velocity vector calculation unit 40, and three-dimensional velocity vectors are obtained.

Note that in FIG. 4, illustrations of the transmitting section, the scanning control section, etc. are omitted.

As described above, according to the ultrasonic Doppler diagnostic apparatus according to the second embodiment, the two-dimensional velocity vector of the first scanning plane and the second
Since it is possible to process the two-dimensional velocity vector of the scanning plane in parallel and obtain them at the same time, the calculation processing time required to analyze the three-dimensional velocity vector can be reduced compared to the first embodiment shown in Fig. 3. It has the advantage of being able to be displayed quickly.

On the other hand, the first embodiment shown in FIG. 3 has a simpler configuration than the second embodiment shown in FIG. 4, so it has the advantage that the apparatus can be simplified.

In either case, each scanning plane simultaneously receives the reflected wave from the moving reflector from two different directions for one wave transmission, and further extracts the velocity component along the received beam from the received signal. Since the calculation can be performed in parallel, it is possible to perform the processing more quickly than with conventional devices, and it is also possible to calculate the three-dimensional velocity vector with high accuracy.

Next, FIGS. 5 and 6 show other embodiments of the transducer array structure in the ultrasonic probe 20.

FIG. 5 shows the concept of a matrix array type transducer 60 in which ultrasonic transducer elements are arranged in a two-dimensional matrix.

According to such a matrix array type vibrator 60, the rotation control unit 24 shown in FIG. 3 is not required, and by switching between transmission and reception of each vibrating element, as shown in FIG. Furthermore, it is possible to form the scanning plane 62 of t81 and the second scanning plane 64 at a desired intersecting angle.

Note that the matrix array type vibrator 6 shown in FIG.
In the transmission and reception of ultrasonic waves by 0, the provision of two reception beams for the transmission beam is the same as described above.

Further, FIG. 6 shows a pipe lane type transducer 70 in which a plurality of rectangular ultrasonic transducers are arranged orthogonally to each other.

According to such a pie-brane type vibrator, the intersection angle of the two scanning planes is set to 90°, but compared to the matrix array type vibrator 60 shown in FIG. It has the advantage of simplifying the process.

Using such a vibrator, the first scanning plane 62 and the second scanning plane 64 can be formed at the same time, and by simultaneously capturing the velocity information of the motion reflector, for example, as shown in FIG. By applying the ultrasonic Doppler diagnostic apparatus according to the second embodiment shown, it is possible to perform calculation processing of a three-dimensional velocity vector even more quickly.

Note that the frequencies of the ultrasonic waves forming each scanning surface do not have to be the same, and may be different frequencies.

Furthermore, the arrangement structure of the ultrasonic transducers in the ultrasonic probe 20 is not limited to that shown above, and may be any other structure as long as the intersection angle between the first scanning plane and the second scanning plane is known. It is also possible to apply the following.

[Effects of the Invention] As explained above, according to the ultrasonic Doppler diagnostic apparatus according to the present invention, reflected waves from a motion reflector are simultaneously received from different positions, and velocity components along each receiving beam are detected. can be obtained in parallel, so it is possible to quickly measure the three-dimensional velocity vector of the motion reflector, and it is also possible to measure the three-dimensional velocity vector with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a principle explanatory diagram showing the principle of obtaining a two-dimensional velocity vector according to the present invention, Fig. 2 is a principle explanatory diagram showing the principle of obtaining a three-dimensional velocity vector according to the present invention, and Fig. 3 is a principle explanatory diagram illustrating the principle of obtaining a three-dimensional velocity vector according to the present invention. FIG. 4 is a block diagram showing a first embodiment of the ultrasonic Doppler diagnostic device according to the present invention, FIG. 4 is a block diagram showing a second embodiment of the ultrasonic Doppler diagnostic device according to the present invention, and FIG. 5 is a concept of a matrix array type transducer. Fig. 6 is a conceptual diagram showing the concept of a pie-brane type resonator. 10, 11. 12. 62. 64 ... Scanning plane 20 ... Ultrasonic probe 30.32 ... Receiving section 34.36 ... Velocity calculation section 38 ... Two-dimensional velocity vector calculation section 40 ...
Three-dimensional velocity vector calculation unit 42 ... Digital scan converter 100 ... Transmission beam 102.104 ... Reception beam ■ ... Three-dimensional velocity vector U ... Two-dimensional velocity vector UR/UL Reception wave velocity component along the beam

Claims (1)

[Scope of Claims] Ultrasonic waves are transmitted and received within a first scanning plane formed by scanning an ultrasound beam, and a first two-dimensional waveform in the first scanning plane of the motion reflector is detected from the received signal. The first step is to find the velocity vector.
transmitting and receiving ultrasonic waves in a second scanning plane whose scanning direction differs by a predetermined angle from the first scanning plane, and scanning the second scanning of the motion reflector based on the received wave signal. A second transmitting/receiving wave to obtain a second two-dimensional velocity vector on the surface.
velocity calculation means; and three-dimensional velocity vector calculation means for determining a three-dimensional velocity vector of the motion reflector from the first and second two-dimensional velocity vectors, the first and second wave transmission/reception/velocities The calculation means is configured to set two reception beams that intersect the transmission beam from two different directions in the scanning plane, and to transmit and receive the reflected waves from the motion reflector simultaneously in the two different directions. a wave unit; two velocity calculating units provided for each of the two receiving beams in the wave transmitting/receiving unit, each of which calculates a velocity component along the receiving beam of the motion reflector from the receiving signal; a two-dimensional velocity vector calculation unit that calculates a two-dimensional velocity vector in the scanning plane of the motion reflector from the two velocity components determined by the calculation unit and the intersection angle of the two received beams; An ultrasonic Doppler diagnostic device featuring: