JP3034786B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called ultrasonic Doppler diagnostic apparatus for measuring a moving speed of a subject tissue using ultrasonic information and diagnosing a moving state of the subject tissue.

[0002]

2. Description of the Related Art Conventionally, as an ultrasonic diagnostic apparatus for diagnosing the motion state of a subject, an ultrasonic Doppler diagnostic apparatus capable of real-time color display of a two-dimensional distribution of the motion speed of the subject has been known. In this ultrasonic Doppler diagnostic apparatus, for example, when diagnosing a heart, a high-pass filter is used to extract a Doppler signal relating to blood moving at a relatively high speed.
Further, a low-pass filter is used to extract a Doppler signal relating to a living tissue such as a heart valve or a myocardium that moves at a low speed. Then, by selectively displaying the obtained two Doppler information (high-speed Doppler information and low-speed Doppler information), the movement speed of a specific region of the subject moving at various speeds is measured, and the heart function and the like are measured. Diagnosis of abnormalities was performed.

FIG. 7 shows a display example of a motion velocity distribution of a living tissue by a conventional ultrasonic Doppler diagnostic apparatus. In this figure and the figures described below, the subject is described taking the heart as an example, and the subject tissue is the myocardium of the heart.

During the diastole of the heart, the myocardial tissue 12f in a region near the probe 10 moves in a direction approaching the probe 10, and the myocardial tissue 12b in a region far from the probe 10 is moved.
Moves in a direction away from the probe 10. Therefore, when the obtained Doppler signal is displayed in color in the same manner as the conventional blood flow display, the myocardial tissue 12f approaching the probe 10 is displayed in red, and the myocardial tissue 12b moving away from the probe 10 is displayed in blue.

On the other hand, during the systole of the heart (not shown), the myocardial tissue 12f near the probe 10 is
Displayed in blue to move away from 0,
The myocardial tissue 12b in a region far from the probe 10 moves in a direction approaching the probe 10 and is displayed in red.

[0006]

[SUMMARY OF THE INVENTION However, in the conventional ultrasonic diagnostic apparatus obtains a motion reference point is the center of movement of the subject, measuring the relative motion of each body tissue of the analyte to the movement reference point However, no consideration was given to diagnosing the subject tissue.

Therefore, the applicant of the present invention has proposed an ultrasonic diagnostic apparatus which obtains a motion reference point G of a subject tissue and calculates and displays a relative motion speed Vd of the subject with respect to the motion reference point G. (Japanese Patent Application No. 6-157470).

Hereinafter, this method will be described with reference to FIG. In FIG. 1, a probe 10 is a general sector scan probe for transmitting and receiving an ultrasonic beam to and from a heart as a subject. Also, the blood flow area 16
The (heart chamber region) is a heart chamber area surrounded by myocardial tissue and filled with blood. Assuming that the center of movement in the heart chamber region 16 is a movement reference point G and the movement velocity component of an arbitrary P point of the myocardial tissue with respect to the probe 10 obtained from the reflected beam is Vr, the movement in one frame of the ultrasonic image The relative movement speed Vd of the myocardial tissue P point with respect to the reference point G is obtained by the following equation (1).

[0009]

Vd = Vr × (1 / cosβ) (1) where β in the equation (1) is an angle between the ultrasonic beam axis at the point P and the straight line GP. , And the relative speed coefficient k
(= 1 / cos β) is a value determined based on the positional relationship between the movement reference point G and the point P.

However, for example, in the sector type ultrasonic image as shown in FIG. 1 where the number of lines of the ultrasonic beam axis is 64 and the depth from the probe 10 is 512 points, the area of the heart chamber region 16 is a line. Number n, depth is number m of points
, The relative speed coefficient k is [64 × 512 × (n
× m)].

Therefore, if the relative velocity coefficient k is calculated and obtained for each frame of the ultrasonic image, it takes time for the calculation process, and it is difficult to display the ultrasonic image in real time. On the other hand, there is a problem that a large-scale memory is required to store all the relative speed coefficients k.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of quickly obtaining a relative movement speed of a subject and displaying the same with a simple apparatus configuration.

[0013]

To achieve the above object, an ultrasonic diagnostic apparatus according to the present invention has the following features.

An ultrasonic diagnostic apparatus for transmitting and receiving an ultrasonic beam to and from an object and displaying an ultrasonic image based on the reflected beam from the object. A speed calculating means for calculating a movement speed of each point of the specimen; and a movement reference point calculating means for calculating a movement reference point of the subject. Further, a coefficient storage in which a relative velocity coefficient corresponding to an angle between a straight line passing from a predetermined reference reference point on the ultrasonic image to a reference point on the ultrasonic image and an ultrasonic beam axis to which the reference point belongs is stored. Means, wherein the relative speed calculation means is the relative speed coefficient stored in the coefficient storage means, wherein the relative speed is read out corresponding to the positional relationship between the movement reference point and each point of the subject. A relative motion speed of each point of the subject with respect to the motion reference point is obtained based on a coefficient and the motion speed of each point of the subject.

Thus, the relative motion coefficient of each point of the subject with respect to the motion reference point is calculated using the relative speed coefficient stored in the coefficient storage means without calculating the relative speed coefficient of each point of the subject for each frame. Speed can be determined. Accordingly, the calculation of the relative movement speed of each point of the subject is performed in a short time, and it is easy to display the obtained relative movement speed of each point of the subject in real time. Further, the coefficient storage means may store at least one relative speed coefficient of the reference point with respect to the reference reference point, and the storage capacity of the coefficient storage means may be small.

In the ultrasonic diagnostic apparatus according to the present invention, in addition to the above-described structure, an angle between an ultrasonic beam axis to which the motion reference point belongs and an ultrasonic beam axis to which each point of the subject belongs, Axial position calculating means for determining an ultrasonic beam axis to which a reference point on the ultrasonic image belongs based on an ultrasonic beam axis to which a reference reference point on the image belongs; and the motion reference point with respect to the origin of the ultrasonic beam. And a depth direction calculating means for calculating a depth of a reference point on the ultrasonic image with respect to an origin of the ultrasonic beam based on a ratio of two distances of the reference reference point. Then, by reading and using the relative velocity coefficient for the reference point specified by the two position calculation means from the coefficient storage means, the relative movement speed of each point of the subject with respect to the movement reference point is obtained.

Further, the moving speed component of the motion reference point is subtracted from the moving speed of each point of the subject in the ultrasonic beam axis direction to calculate the motion speed of each point of the subject in the ultrasonic beam axis direction. A speed component calculating unit for obtaining a component; wherein the relative speed calculating unit obtains a relative motion speed of each point of the subject with respect to the motion reference point by multiplying the motion speed component by the relative speed coefficient; Therefore, the motion of the whole subject is removed, and it becomes easy to confirm the unique motion of the living tissue or the like at each point of the subject.

Further, the relative movement speed of each point of the subject obtained as described above is displayed on a display means as a two-dimensional image, and moves in a direction approaching the movement reference point in the two-dimensional image. The relative movement speed of each object point is represented by a predetermined color, and the relative movement speed of each object point moving in a direction away from the movement reference point is the object movement point of the object moving in the approaching direction. Is represented by a predetermined color different from the relative movement speed. Therefore, for example, when the subject is a heart, during the systole of the heart, the myocardial tissue moves in a direction approaching the motion reference point regardless of the distance from the probe, and the entire myocardial region on the screen is the same. It is displayed in the color of. Conversely, during the diastole of the heart, the myocardial tissue moves in a direction away from the reference point of motion, so that it is displayed in the same color as the systole.

Therefore, it is easy to grasp the motion state of the subject in each time phase.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, the principle of calculating the relative movement speed Vd of each point P of the subject with respect to the movement reference point G is the same as that of FIG.

In this embodiment, in order to enable real-time display of the relative movement speed of the subject tissue, an arbitrary point is set as a reference reference point Gs, and each point on the ultrasonic image with respect to this reference reference point Gs is set. A coefficient table of the relative velocity coefficient k (= 1 / cos β) at the reference point Ps is created and stored in a memory (for example, a ROM) in advance.
For this reason, the relative motion speed of the P point of the subject can be quickly obtained by referring to the corresponding coefficient table without calculating the relative speed coefficient k at the P point of the subject.

Hereinafter, a method of referring to the coefficient table will be described with reference to FIG.

In FIG. 2, the probe has an origin O of polar coordinates,
The angle formed by each ultrasonic beam line 1 (for example, 1 to 64) is a constant value α, and the motion reference point of the subject is the motion reference point G
(L _G , d _G ), an arbitrary measurement point such as myocardial tissue is a point P (l
_P , d _P ). The reference reference point in the coefficient table is a reference reference point Gs ( _lGs , _dGs ), and the angle between the straight line OG and the straight line GP is γ.

As shown in FIG. 2, the relative velocity coefficient k (= 1 / cos) for the point P of the subject with respect to the movement reference point G
β) is the angle between the straight line OG and OP (n × α;
(n is the number between the lines of OG and OP) on the ultrasonic beam line (L) at a position away from the straight line OGs and on a straight line extending at an angle γ to the straight line OGs. L, D). Therefore,
By specifying the position (ultrasonic beam line L and depth D) of the reference point Ps corresponding to the measurement point P of the subject, it becomes possible to read out the necessary relative velocity coefficient k from the coefficient table ROM.

In this embodiment, since the angle α of each ultrasonic beam line is equal, the angle (n × α) between the straight line OG and the straight line OP, that is, the ultrasonic beam line (l _G ) And the difference in the number of lines between the ultrasonic beam line (l _P ) to which the measurement point P belongs is [l _G- l _P ].
The ultrasonic beam line L to which the reference point Ps belongs is based on the ultrasonic beam line (I _Gs ) to which the reference reference point Gs belongs as shown in the following equation (2) and the line number difference [I _G -I _P ]. You can ask.

[0026]

L = l _Gs- (l _G -l _P ) (2) where l _Gs indicates the ultrasonic beam line to which the reference reference point Gs belongs.

Since the triangle OGP and the triangle OGs Ps are similar, the depth D of the reference point Ps (= r _Ps : OP
s) can be obtained by the following equation (3) based on the similarity ratio of triangles.

[0028]

R _Ps = r _P × (d _Gs / d _G ) (3) In the equation (3), r _P is the length of the straight line OP.

By the above-described arithmetic processing, the position (coordinate) of the reference point Ps having the relative velocity coefficient k equal to the relative velocity coefficient k of the measurement point P with respect to the movement reference point G can be specified. Therefore, the relative velocity coefficient k of the specified reference point Ps is read from the coefficient table ROM, and the equation (1)
, The relative movement speed Vd of an arbitrary point P with respect to the movement reference point G of the subject specified for each frame of the ultrasonic image can be obtained.

The depth position of the reference reference point Gs is set to a depth position near the center of the ultrasonic image since the movement reference point G is often specified near the center on the ultrasonic image. It is preferable that the line position of the reference reference point Gs is also the ultrasonic beam position near the center on the ultrasonic image for the same reason.

Further, at the right point (PsR) and the left point (PsL) on the ultrasonic image which are symmetrical with respect to the ultrasonic beam to which the reference reference point Gs belongs, the relative velocity coefficient k (= 1 / cosβ) is the same. Therefore, as shown in FIG. 2, the reference reference point Gs is set on the center ultrasonic beam line on the ultrasonic image, and for example, the address of one relative velocity coefficient k on the coefficient table ROM is set on the ultrasonic image. Left and right points (P
sR, PsL), the relative velocity coefficient k to be stored
Can be reduced to about half. In this case, a ROM having a smaller storage capacity can be used for the coefficient table ROM.

[Configuration of Apparatus] Next, the configuration of an ultrasonic Doppler diagnostic apparatus according to an embodiment of the present invention will be described with reference to FIG.

The probe 10 is shown as a sector scan type probe in the examples of FIGS. 1 and 2, but a convex type probe or the like can also be used. The probe 10 transmits an ultrasonic beam to a subject based on a control signal supplied from the scanning control unit 53 to the transmission / reception unit 20, and receives a reflected echo thereof. Note that the scanning control unit 53 generates a control signal based on the timing signal supplied from the timing signal generation unit 55.

An amplifier 22 and a quadrature detector 30 are connected to the transmitter / receiver 20, and a detector 24 is further connected to the amplifier 22. The detection unit 24 includes the probe 1
The two-dimensional tomographic image (so-called B-mode image) information of the subject is extracted based on the amplitude information of the reflected wave from the subject supplied from 0 through the transmission / reception unit 20. The obtained tomographic image information is supplied to the A / D converter 26, where it is converted into digital data and supplied to the motion reference point calculator 40.

The motion reference point calculation unit 40 determines the area S of the heart chamber region 16 and the small area region ΔSi of the heart chamber region 16 as shown in FIG. . Specifically, when an arbitrary initial point G0 is set in the heart chamber by the operator of the apparatus, an axis extending radially from the initial point G0 is automatically set, and a heart wall point Pi on the axis is detected ( For example, when the number of radiation axes is 64, i is 0 to 63). Next, the area of the triangle G0 Pi Pi + 1 is determined, and the value is set as each minute area ΔSi.

Further, the motion reference point calculating section 40 calculates each ΔSi
And the area S of the heart chamber region 16 are determined. Then, using the obtained ΔSi, S, and Rgi,
The motion reference point G of the heart chamber region 16 and its position vector Rg are obtained by the following equation (4). In the text of the specification (excluding mathematical formulas), the symbol → of a vector is omitted.

[0037]

(Equation 4) The method of calculating the small area ΔSi is not limited to the above method. For example, as in the related Japanese Patent Application No. 6-157470, the small area ΔSi of the heart chamber region 16 between adjacent ultrasonic beam lines may be obtained. However, in the above method, ΔSi with high approximation can be obtained by relatively simple arithmetic processing, and the accuracy of the motion reference point and its position vector calculated based on ΔSi can be improved.

Next, the motion reference point calculating section 40 sets the motion reference point G obtained by the above method as an arbitrary initial point G0 in the heart chamber in the next frame. Then, by the same procedure, the motion reference point G of the heart chamber region 16 and its position vectors Rg (n), Rg (n) for each frame (n), (n + 1).
+1), and a reference motion speed vector v _G of the motion reference point _G is calculated based on the following equation (5).

[0039]

(Equation 5) The motion reference point G and the reference motion speed vector v _G obtained as described above are supplied to the coefficient calculation unit 50 and the speed component calculation unit 62 of the speed correction unit 60.

The contour between the myocardial tissue 12 and the heart chamber region 16 is determined, for example, at each intersection between the radiation axis and the ultrasonic beam line from the tomographic image information (amplitude information) obtained from the received wave. Can be determined by detecting the presence or absence of a peak occurring at the boundary of. Further, the tomographic image information is subjected to an averaging process, and the tomographic image information is converted using a predetermined threshold value lower than the amplitude value (luminance value) due to the myocardial tissue 12 and higher than the amplitude value (luminance value) due to blood. If the outline of the myocardial tissue 12 is determined based on the binarization, a more accurate outline can be extracted.

The quadrature detector 30 connected to the transmitter / receiver 20
Is a detector for obtaining a Doppler signal from the ultrasonic signal received by the probe 10, and multiplies the received signal by a reference signal having a phase difference of 90 degrees supplied from the timing signal generator 55. To perform quadrature detection.

The low-pass filter 32 connected to the quadrature detector 30 converts a Doppler signal composed of two signals of a real component and an imaginary component obtained by the quadrature detection from
Only Doppler signals in the low frequency band are extracted. Here, if the subject is a heart, the Doppler signal in the low frequency band is a signal relating to a living tissue such as a myocardium. Therefore, if the Doppler signal in the high frequency band caused by the blood flowing in the heart chamber region 16 in FIG. 5 is removed from the Doppler signal obtained by the quadrature detection using the low-pass filter 32, the Doppler signal in the myocardial tissue 12 region Are selectively extracted. It is not always necessary to provide the low-pass filter 32 to selectively extract the Doppler signal in the myocardial tissue 12 region, and the high-pass filter used in the conventional ultrasonic Doppler diagnostic apparatus may be simply removed.

The low-pass filter 32 includes an autocorrelation unit 3
The autocorrelation unit 34 performs a correlation operation on the extracted low frequency band Doppler signal. The velocity calculator 36 calculates an arbitrary point P of the subject with respect to the probe 10 based on the correlation signal obtained by the autocorrelator 34.
The motion velocity component v _r of the ultrasonic beam axis direction of the (eg, myocardial tissue 12) is determined (see FIG. 5). The obtained coordinates of the arbitrary point P of the subject and the movement speed component v _r thereof are temporarily stored in the Doppler frame memory 38 and supplied to the speed component calculation unit 62 of the speed correction unit 60 at a predetermined timing.

The velocity component calculating unit 62, the components on the ultrasound beam axis j of the reference motion velocity vector v _G from motion velocity component v _r of the object as in the following equation (6) [(Vector | v _G
|) × cos θ], and the velocity component Vr at point P of the subject
Ask for.

[0045]

(Equation 6) Here, θ is the angle between the ultrasonic beam axis j and the reference motion speed vector v _G, and the angle between the reference motion speed vector v _G at the motion reference point _G and the straight line OG and the straight line OP (n × α), that is, in this embodiment, the difference between the numbers of ultrasonic beam lines to which the motion reference points G and the points P belong, respectively.

As shown in FIG. 4, the coefficient calculator 50 has a line number calculator 52, a depth calculator 54, and a coefficient table ROM 56. The line number calculator 52 includes a line number 1 _G of the motion reference point G supplied from the motion reference point calculator 40 and a point P of the subject tissue supplied from the speed calculator 36 via the Doppler frame memory 38. (2) is calculated based on the line number l _{P of} the reference point Gs and the line number l _Gs of the reference reference point Gs set in advance, and the line number L to which the reference point Ps of FIG. 2 belongs is obtained.

On the other hand, the depth calculator 54 calculates the depth d _G of the motion reference point G supplied from the motion reference point calculator 40 and the depth d of the point P of the subject tissue supplied from the Doppler frame memory 38. numbered d _P, based on the depth d _Gs reference reference point Gs which is set in advance, calculates the equation (3), determine the depth D of the reference point Ps. As shown in FIG. 2, the coefficient table ROM 56 stores a relative velocity coefficient k (= 1 / cos) of each reference point Ps on the ultrasonic screen with respect to the reference reference point Gs.
β) is stored. Therefore, when the line number and the depth of the reference point Ps are obtained, the relative speed coefficient k of the reference point Ps is obtained from the corresponding address in the coefficient table ROM 56.
(= 1 / cos β) is read out and output to the relative speed calculation unit 66.

The relative speed calculator 66 calculates the relative speed coefficient k (= 1 / cos β) corresponding to the point P supplied from the coefficient calculator 50 and the speed component calculator 6 as shown in equation (1).
2 is multiplied by the velocity component Vr of the point P in the direction of the ultrasonic beam axis supplied from the point P.
Is obtained.

The obtained relative movement speed Vd is supplied to a display unit 74 via a DSC 70 and a D / A conversion unit 72 connected to a relative speed calculation unit 66. The display unit 74 includes a hatched portion in FIG. The two-dimensional relative movement velocity distribution 12r of the living tissue with respect to the movement reference point G is displayed as shown in FIG.

In the display, in the color Doppler method, the relative movement speed of the myocardial tissue moving in the direction approaching the movement reference point G is displayed in a predetermined color (for example, red), and the relative movement speed is determined in the direction away from the movement reference point G. The relative movement speed of the moving myocardial tissue is displayed in a different color (for example, blue) from the relative movement speed of the moving myocardial tissue.

Therefore, during the systole of the heart, the myocardial tissue moves in a direction approaching the movement reference point G irrespective of the distance from the probe 10, so that the relative movement velocity distribution of the myocardial tissue 1
2r is displayed in the same color. Conversely, during the diastole of the heart, the myocardial tissue moves in a direction away from the center of gravity G as shown in FIG.
Are displayed in the same color different from the systole.

Therefore, when such a color display is performed, it is possible to confirm the motion state of each time phase of the subject. Further, if the display luminance is changed according to the magnitude of the relative movement speed, a more detailed movement state at each point of the living tissue can be measured and diagnosed. Note that the position of the movement reference point G supplied from the movement reference point calculation unit 40 may be combined with the relative movement speed distribution 12r and displayed on the display unit 74 as needed.

Further, in this embodiment, the motion reference point is obtained based on the tomographic image information (amplitude information) of the myocardial tissue.
The contour of the heart chamber region 16 in the myocardial tissue 12 in FIG. 1 may be obtained from the two-dimensional motion velocity distribution of the myocardial tissue or the two-dimensional motion velocity distribution of the blood.

In general, in an ultrasonic Doppler diagnostic apparatus, the movement speed of a region moving in a direction perpendicular to the ultrasonic beam axis cannot be obtained due to the principle of the Doppler effect as shown in FIG. However, for example, by performing a predetermined interpolation process such as transmitting and receiving an ultrasonic wave from another direction, it is also possible to display a relative motion velocity distribution of a living tissue without any loss as shown in FIG. .

[0055]

As described above, according to the ultrasonic diagnostic apparatus of the present invention, the relative velocity coefficient stored in the coefficient storage means is used without calculating the relative velocity coefficient for each point of the subject. Thus, the relative movement speed of each point of the subject with respect to the movement reference point can be obtained. Accordingly, the calculation of the relative movement speed of each point of the subject is performed in a short time, and it is easy to display the obtained relative movement speed of each point of the subject in real time. Further, the coefficient storage means may store at least one relative speed coefficient of the reference point with respect to the reference reference point, and the storage capacity of the coefficient storage means may be small.

Further, by subtracting the moving speed component of the motion reference point of the subject from the relative motion speed of each point of the subject,
The movement of the entire subject is removed, and the unique movement speed of each living tissue or the like can be detected, and it is possible to accurately diagnose abnormal movement of the living tissue due to myocardial infarction or the like.

Further, by changing the color used for displaying on the display means according to the relative movement direction of each point of the subject with respect to the movement reference point, the movement state of each time phase of the subject can be easily confirmed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a method for obtaining a relative movement speed of each point P of a subject with respect to a movement reference point G of the subject.

FIG. 2 is a conceptual diagram illustrating a method of referring to a coefficient table according to the present embodiment.

FIG. 3 is a schematic configuration diagram of an ultrasonic diagnostic apparatus of the present embodiment.

FIG. 4 is a diagram illustrating a configuration of a coefficient calculation unit 50 of FIG. 3;

FIG. 5 is a conceptual diagram illustrating a calculation process performed in the ultrasonic diagnostic apparatus of FIG. 3;

FIG. 6 is a diagram showing a display example of a relative movement velocity distribution of myocardial tissue with respect to a movement reference point according to the embodiment.

FIG. 7 is a diagram showing a display example of a motion velocity distribution of myocardial tissue by a conventional ultrasonic Doppler diagnostic apparatus.

[Explanation of symbols]

Reference Signs List 10 probe, 12 myocardial tissue, 12r relative motion velocity distribution, 16 heart chamber region, 40 motion reference point calculation unit, 50
Coefficient operation unit, 52 line number operation unit, 54 depth operation unit, 56 coefficient table ROM, 60 speed correction unit, 6
2 speed component calculation unit, 66 relative speed calculation unit, 74 display unit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-303642 (JP, A) JP-A-8-19540 (JP, A) JP-A-6-285065 (JP, A) JP-A-5-205 56975 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 8/00-8/14 WPI / L (QUESTEL)

Claims (4)

(57) [Claims] 1. An ultrasonic diagnostic apparatus for transmitting and receiving an ultrasonic beam to and from an object and displaying an ultrasonic image based on a reflected beam from the object, comprising: Speed calculation means for calculating the movement speed of each point of the subject, motion reference point calculation means for calculating the movement reference point of the subject, and a reference point on the ultrasound image from a predetermined reference reference point on the ultrasound image. A passing straight line, an ultrasonic beam axis to which the reference point belongs, and a coefficient storage means storing a relative speed coefficient corresponding to an angle formed by the relative speed coefficient stored in the coefficient storage means, The relative velocity coefficient read out in correspondence with the positional relationship between the movement reference point and each point of the subject, and the movement speed of each point of the subject, based on the movement reference point, Phase for calculating relative motion speed Ultrasonic diagnostic apparatus characterized by comprising: a speed calculation means. 2. The ultrasonic diagnostic apparatus according to claim 1, further comprising: an angle between an ultrasonic beam axis to which the movement reference point belongs and an ultrasonic beam axis to which each point of the subject belongs; Axial position calculating means for determining the ultrasonic beam axis to which the reference point on the ultrasonic image belongs based on the ultrasonic beam axis to which the reference reference point on the image belongs; and the motion reference point with respect to the origin of the ultrasonic beam. And a depth direction calculating means for calculating a depth of a reference point on the ultrasonic image with respect to an origin of the ultrasonic beam based on a ratio of two distances of the reference reference point, and Reading the relative velocity coefficient for the reference point on the ultrasonic image specified by the position calculation means from the coefficient storage means, and obtaining the relative movement velocity of each point of the subject with respect to the movement reference point. And the ultrasonic diagnostic apparatus. 3. The ultrasonic diagnostic apparatus according to claim 1, further comprising: subtracting a moving speed component of the motion reference point from a moving speed of each point of the subject in an ultrasonic beam axis direction. Then, there is a speed component calculating means for obtaining a moving speed component of each point of the subject in the ultrasonic beam axis direction, the relative speed calculating means multiply the moving speed component by the relative speed coefficient An ultrasonic diagnostic apparatus, wherein a relative movement speed of each point of the subject with respect to the movement reference point is obtained. 4. The ultrasonic diagnostic apparatus according to claim 1, wherein the relative movement speed of each point of the subject is displayed on a display unit as a two-dimensional image. The relative movement speed of each point of the subject moving in a direction approaching the movement reference point is represented by a predetermined color, and the relative movement speed of each point of the subject moving away from the movement reference point is An ultrasonic diagnostic apparatus, wherein the ultrasonic diagnostic apparatus is represented by a predetermined color different from a relative movement speed of each point of the subject moving in the approaching direction.