JP4350994B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic diagnostic apparatus that measures blood flow velocity.

  For example, Patent Document 1 below discloses an ultrasonic diagnostic apparatus that measures a blood flow velocity. According to this apparatus, the first beam is set so as to be orthogonal to the blood vessel, and tracking on the front wall and the rear wall of the blood vessel, that is, a minute displacement measurement is started on the first beam. On the other hand, the second beam for Doppler measurement is automatically set so as to intersect the midpoint of the front wall and the rear wall, and the blood flow velocity is measured on the second beam. Then, a wave intensity as a circulatory dynamic index is calculated from the blood vessel diameter and blood flow velocity obtained by the minute displacement measurement. FIG. 7 shows that the blood flow velocity vector is calculated by the two-beam simultaneous forming technique.

JP 2001-218768 A

  In an ultrasonic diagnostic apparatus that measures blood flow velocity by the Doppler method, velocity information that can be directly measured from Doppler information is blood flow velocity information in the beam direction for Doppler measurement. That is, the blood flow velocity component in the Doppler measurement beam direction that obliquely intersects the blood flow direction is measured. Therefore, in order to measure the blood flow velocity in the blood flow direction, the true blood flow velocity in the blood flow direction is calculated from the blood flow velocity component in the beam direction using the intersection angle between the Doppler measurement beam and the blood flow. It is desirable to derive. However, Patent Document 1 does not describe deriving the blood flow velocity from the intersection angle between the Doppler measurement beam (second beam) and the blood flow.

  In order to measure the true blood flow velocity in the blood flow direction, a method is known in which the user measures the crossing angle on the tomographic image displayed on the display when determining the crossing angle between the Doppler measurement beam and the blood flow. It has been. However, this method requires a complicated operation by the user.

  Therefore, an object of the present invention is to easily obtain the true blood flow velocity in the blood flow direction without causing a special burden on the user.

  In order to achieve the above object, an ultrasonic diagnostic apparatus according to a preferred aspect of the present invention specifies a first beam setting means for setting a first beam that intersects a blood vessel at a predetermined angle, and is specified by the first beam. Second beam setting means for setting a second beam that passes through a reference point in the blood vessel and intersects the blood flow in the blood vessel at an angle, and Doppler information acquired by the second beam Based on the velocity component calculating means for calculating the blood flow velocity component in the second beam direction, the intersection angle of the first beam with respect to the blood vessel, the deflection angle of the first beam, and the deflection angle of the second beam. An angle calculating means for calculating a crossing angle of the second beam with respect to the blood flow, and a speed calculating means for calculating a blood flow speed based on the blood flow velocity component and the crossing angle of the second beam with respect to the blood flow. It shall have the.

  According to the above configuration, the angle calculation means calculates the intersection angle of the second beam with respect to the blood flow, and the speed calculation means calculates the blood flow velocity based on the intersection angle and the blood flow velocity component. The true blood flow velocity in the blood flow direction can be easily obtained without causing a special burden on the user.

  Preferably, the first beam is a blood vessel wall displacement measuring beam, and a front wall position and a rear wall position of the blood vessel are specified on the first beam, and a reference point in the blood vessel is the front wall. It shall be set based on the position and the rear wall position. More preferably, the front wall position and the rear wall position of the blood vessel are specified following the movement of the blood vessel wall.

  Desirably, the second beam setting means sets the deflection angle of the second beam so that the crossing angle of the second beam with respect to the blood flow is not more than a predetermined angle. Desirably, blood vessel diameter calculating means for calculating a blood vessel diameter based on the front wall position and the rear wall position of the blood vessel specified on the first beam, and blood based on the blood vessel diameter and the blood flow velocity. And an evaluation value calculating means for calculating an evaluation value related to the flow. Desirably, the velocity component calculating means calculates the blood flow velocity component for each position on the second beam in the blood vessel, and the velocity calculating means calculates the blood flow velocity corresponding to each position. The blood flow velocity is calculated for each position based on the component.

  With the ultrasonic diagnostic apparatus according to the present invention, it is possible to easily obtain the true blood flow velocity in the blood flow direction without causing a special burden on the user.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the overall configuration of an ultrasonic diagnostic apparatus that is a preferred embodiment of the present invention. In FIG. 1, a probe 10 is an ultrasonic probe that transmits ultrasonic pulses and receives echoes. The probe 10 has a plurality of array transducers, and an ultrasonic beam is electronically scanned by electronic scanning of the array transducers. Examples of the electronic scanning method include electronic linear scanning and electronic sector scanning. The ultrasonic diagnostic apparatus according to the present embodiment has a function of measuring the properties of the blood vessel 14, and the scanning plane formed by scanning the ultrasonic beam coincides with the central axis of the blood vessel 14 in the measurement. Thus, the contact position and contact posture of the probe 10 with respect to the living body surface 12 are adjusted by manual operation.

  The transmission / reception unit 16 supplies a transmission signal to the probe 10 and performs processing such as amplification and phasing addition on the reception signal from the probe 10. The operation of the transmission / reception unit 16 is controlled by the transmission / reception control unit 18.

  The transmission / reception control unit 18 executes transmission / reception control for forming a transmission beam and a reception beam. As will be described later, the transmission / reception control unit 18 generates an ultrasonic beam (blood vessel wall displacement measurement beam) for blood vessel wall displacement measurement based on the deflection angle set in the blood vessel wall displacement measurement beam direction setting unit 2. In addition, an ultrasonic beam (flow velocity measurement beam) for blood flow velocity measurement is formed based on the deflection angle set in the blood flow velocity measurement beam direction setting unit 4.

  Here, the deflection angles of the blood vessel wall displacement measurement beam and the flow velocity measurement beam will be described with reference to FIG. The deflection angle φ of the blood vessel wall displacement measurement beam 40 is set so as to intersect perpendicularly to the blood vessel wall 44 of the blood vessel 14. The deflection angle φ is a beam angle with respect to the normal line of the transducer surface of the probe 10. The deflection angle φ is set in the blood vessel wall displacement measurement beam direction setting unit 2 (FIG. 1). The blood vessel wall displacement measuring beam direction setting unit 2 performs deflection based on the beam direction designated by the user using a pointing device such as a trackball while viewing the image displayed on the display unit 36 (FIG. 1), for example. Set the angle φ. Of course, the vascular wall displacement measurement beam direction setting unit 2 itself may automatically set the deflection angle φ using, for example, a known method.

  The deflection angle ξ of the flow velocity measurement beam 42 is set so as to intersect the blood flow in the blood vessel 14 from an oblique direction. The deflection angle ξ is a beam angle with respect to the normal line of the transducer surface of the probe 10. The deflection angle ξ is set in the blood flow velocity measuring beam direction setting unit 4 (FIG. 1). The blood flow velocity measuring beam direction setting unit 4 calculates the position of the midpoint 50 based on the position of the front wall 46 and the position of the rear wall 48 of the blood vessel 14 output from the displacement calculation unit 26 described later. The flow velocity measurement beam 42 is set so that the flow velocity measurement beam 42 passes through the midpoint 50. The midpoint 50 is only an example of a position that is determined based on the position of the front wall 46 and the position of the rear wall 48. For example, the position of the front wall 46 or the position of the rear wall 48 itself may be used instead of the midpoint 50, or an arbitrary point between the front wall 46 and the rear wall 48 may be used. Good.

  Returning to FIG. 1, the displacement calculation unit 26 detects the displacement of the position of the blood vessel wall, specifically, the position of the front wall 46 (FIG. 2) on the near side as viewed from the probe 10, and the back side as viewed from the probe 10. The position of a certain rear wall 48 (FIG. 2) is calculated. The position information of the front wall 46 and the rear wall 48 calculated by the displacement calculation unit 26 is used by the blood flow velocity measurement beam direction setting unit 4 to set the deflection angle ξ. The displacement calculator 26 also has a function of calculating a blood vessel diameter from the position of the front wall 46 and the position of the rear wall 48.

  At this time, the displacement calculator 26 tracks the position of the blood vessel wall on the blood vessel wall displacement measurement beam 40 (FIG. 2). The position of the blood vessel wall is specified by comparing the level of the echo data with a predetermined threshold, and the displacement of the blood vessel wall is tracked by detecting the phase change of the echo data signal. This is a known technique.

  The velocity component calculation unit 28 extracts Doppler information from echo data in the blood vessel 14 on the flow velocity measurement beam 42 (FIG. 2), and calculates a blood flow velocity component based on the extracted Doppler information. The blood flow velocity calculation unit 30 calculates the blood flow velocity from the blood flow velocity component calculated by the velocity component calculation unit 28 and the intersection angle between the flow velocity measurement beam 42 calculated by the intersection angle calculation unit 6 and the blood flow. Calculate.

  Here, the calculation of the blood flow velocity will be described with reference to FIG. In the following description, the parts shown in FIG. The velocity information that can be directly measured by the Doppler method is a velocity component in the beam direction for acquiring Doppler information. That is, blood flow velocity information acquired in the flow velocity measurement beam 42 is a blood flow velocity component Vr in the direction of the flow velocity measurement beam 42. The flow velocity measuring beam 42 is set so as to intersect the blood flow in the blood vessel 14 from an oblique direction. For this reason, in order to calculate the blood flow velocity V that is the velocity in the direction of the blood flow based on the blood flow velocity component Vr, the crossing angle θ with respect to the blood flow of the flow velocity measurement beam 42 is required. The intersection angle θ is calculated by the intersection angle calculation unit 6 as follows.

  The deflection angle φ of the blood vessel wall displacement measuring beam 40 is set so as to intersect perpendicularly to the blood vessel wall 44 of the blood vessel 14. On the other hand, the deflection angle ξ is set so that the flow velocity measurement beam 42 passes through the midpoint 50 on the blood vessel wall displacement measurement beam 40. That is, the intersection angle θ satisfies the relationship θ = 90− | φ | − | ξ |. The intersection angle calculation unit 6 calculates θ = 90− from the deflection angle φ set in the blood vessel wall displacement measurement beam direction setting unit 2 and the deflection angle ξ set in the blood flow velocity measurement beam direction setting unit 4. Based on the relationship of | φ | − | ξ |, the intersection angle θ is calculated.

  When the intersection angle θ is calculated, the blood flow velocity V can be calculated from the relationship V = Vr / cos θ. That is, the blood flow velocity calculation unit 30 calculates the blood flow velocity V from the blood flow velocity component Vr calculated by the velocity component calculation unit 28 and the intersection angle θ calculated by the intersection angle calculation unit 6.

  The blood flow velocity V can be calculated for each position on the flow velocity measurement beam 42 in the blood vessel 44. That is, as the blood flow velocity component Vr, the velocity component can be acquired for each position on the flow velocity measurement beam 42, and the blood flow velocity can be calculated from the relationship of V = Vr / cos θ for each velocity component. For example, it is possible to set a sample gate in a range including the midpoint 50, acquire velocity components at each position in the sample gate, and calculate an average blood flow velocity in the sample gate from the average value. .

  Returning to FIG. 1, the evaluation value calculator 34 calculates an evaluation value related to the vascular function from the blood vessel diameter calculated by the displacement calculator 26 and the blood flow velocity calculated by the blood flow velocity calculator 30. A wave intensity disclosed in Patent Document 1 is preferable as the evaluation value. That is, the evaluation value calculation unit 34 performs unit conversion on the time-varying waveform of the blood vessel diameter based on the blood vessel diameter output from the displacement calculation unit 26 to form a blood pressure waveform, and performs time differentiation of the blood pressure waveform. At the same time, a time differentiation of the time variation waveform of the blood flow velocity output from the blood flow velocity calculation unit 30 is executed, and the wave intensity is obtained by multiplying the blood pressure differentiation result and the blood flow velocity differentiation result.

  The wave intensity value calculated by the evaluation value calculation unit 34 is output to the display processing unit 24. The display processing unit 24 captures image information of the tomographic image formed by the tomographic image forming unit 22, and the display processing unit 24 displays the tomographic image of the blood vessel 14 and the time waveform of the wave intensity on the display unit 36. indicate.

  Next, an operation example of the ultrasonic diagnostic apparatus according to the present embodiment will be described with reference to FIG. The parts described in FIGS. 1 and 2 will be described with reference numerals in FIGS. 1 and 2.

  First, the contact position and contact posture of the probe 10 are adjusted by a user by a user, and a tomographic image of the blood vessel is displayed on the display unit 36 (S101). Next, the blood vessel wall displacement measuring beam 40 is set so as to intersect the blood vessel wall 44 perpendicularly (S102). The deflection angle φ of the blood vessel wall displacement measurement beam 40 is determined based on the beam direction specified by the user while viewing the tomographic image displayed on the display unit 36.

  Next, a tracking point is set by the user at each position of the front wall 46 and the rear wall 48 (S103), and the displacement calculation unit 26 moves on the blood vessel wall displacement measurement beam 40 based on the set tracking point. The position of the blood vessel wall is tracked (S104). Then, the blood flow velocity measurement beam direction setting unit 4 calculates the position of the midpoint 50 based on the position of the front wall 46 and the position of the rear wall 48 (S105), and the flow velocity measurement beam 42 determines the midpoint 50. The flow velocity measurement beam 42 is temporarily set so as to pass (S106).

  When the flow velocity measurement beam 42 is temporarily set, the intersection angle calculator 6 calculates the intersection angle θ from the deflection angle ξ at that time and the deflection angle φ of the blood vessel wall displacement measurement beam 40 set in S102. . However, in order to measure the blood flow velocity more accurately, it is desirable that the crossing angle θ is small. Therefore, the deflection angle ξ of the flow velocity measurement beam 42 is corrected so that the intersection angle θ is equal to or less than a predetermined angle (for example, 60 ° or less) (S107). The deflection angle ξ is corrected by the user specifying the beam direction while viewing the flow velocity measurement beam 42 displayed on the display unit 36. Alternatively, the blood flow velocity measurement beam direction setting unit 4 may automatically set the crossing angle θ output from the crossing angle calculating unit 6.

  Next, the intersection angle θ is calculated from the relationship θ = 90− | φ | − | ξ | in the intersection angle calculation unit 6 from the deflection angle ξ corresponding to the corrected flow velocity measurement beam 42 (S108). The blood flow velocity calculation unit 30 calculates the blood flow velocity V from the relationship of V = Vr / cos θ (S109), and the evaluation value calculation unit 34 calculates the wave intensity that is an evaluation value based on the blood vessel diameter and the blood flow velocity. A city is calculated (S110).

  Although the preferred embodiments of the present invention have been described above, the above-described embodiments are merely examples in all respects and do not limit the scope of the present invention. For example, applying a so-called color Doppler function that calculates a true blood flow velocity in the blood flow direction by a method similar to that of the above-described embodiment and displays a color corresponding to the blood flow velocity on a tomographic image of the blood vessel. Is also possible. In addition, a graph display of a temporal change in the true blood flow velocity in the blood flow direction, a numerical display of the blood flow velocity, or the like may be performed.

1 is a block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present invention. It is a figure for demonstrating the calculation of the deflection angle of a blood vessel wall displacement measurement beam and a flow velocity measurement beam, and a blood flow velocity. It is a figure for demonstrating the operation example of the ultrasonic diagnosing device which concerns on this embodiment.

Explanation of symbols

  2 Beam direction setting unit for measuring blood vessel wall displacement, 4 Beam direction setting unit for measuring blood flow velocity, 6 Crossing angle calculating unit, 26 Displacement calculating unit, 28 Speed component calculating unit, 30 Blood flow rate calculating unit, 34 Evaluation value calculation Department.

Claims (6)

First beam setting means for setting a first beam that intersects the blood vessel at a predetermined angle;
Second beam setting means for setting a second beam that passes through a reference point in the blood vessel specified by the first beam and intersects the blood flow in the blood vessel obliquely;
Velocity component calculating means for calculating a blood flow velocity component in the second beam direction based on Doppler information acquired by the second beam;
Angle calculating means for calculating a crossing angle of the second beam with respect to blood flow based on a crossing angle of the first beam with respect to the blood vessel, a deflection angle of the first beam, and a deflection angle of the second beam;
A velocity calculation means for calculating a blood flow velocity based on an intersection angle of the blood flow velocity component and the blood flow of the second beam;
I have a,
The second beam setting means sets the deflection angle of the second beam so that the crossing angle of the second beam with respect to the blood flow is a predetermined angle or less;
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The first beam is a blood vessel wall displacement measurement beam, and the front wall position and the rear wall position of the blood vessel are specified on the first beam,
The reference point in the blood vessel is set based on the front wall position and the rear wall position.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 2,
The anterior wall position and the posterior wall position of the blood vessel are specified following the movement of the blood vessel wall.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The second beam setting means sets the deflection angle of the second beam so that the crossing angle of the second beam with respect to the blood flow is 60 ° or less.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 2,
A blood vessel diameter calculating means for calculating a blood vessel diameter based on the front wall position and the rear wall position of the blood vessel specified on the first beam;
Based on the blood vessel diameter and the blood flow velocity, evaluation value calculating means for calculating an evaluation value related to blood flow;
And an ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1,
The velocity component calculating means calculates the blood flow velocity component for each position on the second beam in the blood vessel,
The velocity calculation means calculates a blood flow velocity for each position based on a blood flow velocity component corresponding to each position.
An ultrasonic diagnostic apparatus.

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