JP2772048B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention scans a living body with an ultrasonic beam to display an M-mode display image (motion image), a B-mode display image (Tomography), D
Mode display image (blood velocity image), DF mode display image (CFM image: Col
The present invention relates to an ultrasonic diagnostic apparatus that obtains an ultrasonic image such as a flow mapping image or the like and provides it for display for diagnosis.

(Prior Art) An image diagnosis of the heart as a circulatory organ is performed using this type of ultrasonic diagnostic apparatus. At the time of such a diagnosis, a doctor or the like obtains a B-mode display image to obtain anatomical information of the heart to be diagnosed, or obtains an M-mode display image to obtain functional information of the heart, A D-mode display image and a DF-mode display image are obtained in order to know the behavior of the blood flow flowing through the device.

In particular, obtaining a B-mode display image and a D-mode display image at the same time and observing them at the same time is a diagnostic mode that is very often performed, and a diagnostic result of the heart can be obtained effectively. . In this case, the D-mode display uses the Doppler effect, and the moving body in this case is generally a blood flow (blood cell). The angle between the direction and the ultrasonic beam needs to be non-perpendicular.

And since the blood flow direction is a direction along the body surface, linear scanning for transmitting and receiving the ultrasonic beam in a direction perpendicular to the body surface is not suitable, and the ultrasonic beam is directed in a direction non-perpendicular to the body surface, that is, obliquely. Sector scanning for transmission and reception is suitable.

(Problems to be Solved by the Invention) However, the B-mode display image by sector scanning is fan-shaped, and the field of view near the probe is very narrow. It is difficult to observe an image as compared with an image formed by other scanning such as a square image or a trapezoidal image formed by trapezoidal scanning.

Therefore, an object of the present invention is to provide an ultrasonic diagnostic apparatus that facilitates observation and enables diagnosis of a circulatory organ.

[Structure of the Invention] (Means for Solving the Problems) An ultrasonic diagnostic apparatus according to the present invention includes a transmitting / receiving unit that linearly scans an ultrasonic beam transmitted / received to / from a subject from a linear scanning probe, A sample point setting means for setting a sample point at an arbitrary position on the propagation path of the ultrasonic beam according to an operator's request; and setting a deflection angle of the ultrasonic beam to an arbitrary value according to an operator's request. When the deflection angle is reset by the deflection angle setting means and the deflection angle setting means, the position of the previously set sample point on the subject is fixed, and the fixed sample point is Changing means for changing a set value of the sample point setting means so that a position is a sample point of the ultrasonic beam under the reset deflection angle; A video system having at least a D-mode processor for calculating a Doppler shift frequency fd by frequency-analyzing a received signal at the sample point and calculating blood flow velocity information of the subject from the Doppler shift frequency fd; It is characterized by having.

(Operation) According to such a configuration, when a certain sample point is initially set, the position of this sample point is not changed, and the vibrator is set to perform oblique linear scan at a desired swing angle in the Doppler mode. Vibrator selection control including aperture control, delay amount control, and focus control are performed. Therefore, even if the swing angle changes, Doppler information at the same position can be automatically obtained, and scanning can be facilitated and highly accurate diagnosis can be performed.

(Embodiment) First, prior to the description of the embodiment, a scanning method of this type of ultrasonic diagnostic apparatus will be described. Typical examples of the scanning method of the ultrasonic diagnostic apparatus include a linear scanning method and a sector scanning method.

The linear scanning method is a method in which an ultrasonic beam is linearly moved integrally with a transmitting (receiving) point and a transmitting (receiving) direction, and the sector scanning method is a method in which an ultrasonic beam is transmitted by the transmitting (receiving) point. This is a method in which the point of reception (wave reception) is fixed and the direction of transmission (wave reception) is changed.

In this case, there are two methods for performing the scanning: a mechanical method and an electrical method. Hereinafter, a description will be given assuming that a typical electrical method is used.

Usually, the ultrasonic beam is not transmitted (received) by a single ultrasonic transducer, but is transmitted (received) by a plurality of ultrasonic transducers. In this case, the group of ultrasonic transducers that generate the ultrasonic beam in the transmission (reception) is hereinafter referred to as a group of simultaneous driving transducers.

That is, in the linear scanning method, the simultaneously driven transducer group is linearly moved, and in the linear scanning method, the simultaneously driven transducer group is fixed, and each beam from each transducer is matched by the phase control method to transmit (receive). The direction is changed. In this case, the linear scanning method does not actually move the same group of simultaneously driven transducers.Each of the transducers to be simultaneously driven among the many ultrasonic transducer groups is electrically switched. One group or a plurality of groups are sequentially shifted while sequentially shifting one or more groups.

For example, the linear scanning method uses an array-type ultrasonic probe for linear scanning in which a large number of ultrasonic transducers such as 256 are arranged in parallel, and the sector scanning method has a smaller number than the linear scanning method, such as 56. An array-type ultrasonic probe for sector scanning, in which ultrasonic transducers are arranged side by side, is used. In the linear scanning method, a plurality of ultrasonic transducer groups having different combinations in a plurality of ultrasonic probes having different combinations in the array-type ultrasonic probe for linear scanning are regarded as simultaneous driving transducer groups. Further, in the sector scanning method, all ultrasonic transducers of the array type ultrasonic probe for sector scanning are set as a simultaneous drive transducer group (SDTG).

The display modes include M mode display, B mode display, and D mode display.
Mode display, DF mode display, etc. The M mode display is
A change in the time axis of an envelope detection of a received signal of a beam that scans a specific position is displayed. The B mode display is two-dimensionally performed by an ultrasonic beam over a wide range. The received signal is scanned and subjected to envelope detection to two-dimensionally synthesize an image corresponding to the wide range to display a tomographic image.

The D-mode display uses the Doppler effect,
The moving object is generally a blood flow (blood cells). The D mode display includes a PWD mode (pulse Doppler method) and a CWD mode (continuous wave Doppler method) depending on the type of ultrasonic wave used.
According to the PWD mode, a blood flow pattern at an arbitrary specific point can be known, and according to the CWD mode, the maximum flow velocity can be known.

Detection of information in the D mode display is performed as follows. For example, in the PWD mode, for example, an ultrasonic pulse beam is transmitted to a blood vessel in a living body in a direction that is not orthogonal to the blood vessel running method, and only a signal from a specific point (position) in the received signal is transmitted. The signal is extracted (sampled), the signal is subjected to frequency analysis by a fast Fourier transform process or the like, and a blood flow pattern is known. In the PWD mode described above, Doppler information for a specific point is obtained, that is, one-point Doppler measurement. This is extended to multiple points, that is, DF mode display is for multipoint Doppler measurement.

In the DF mode display, for example, in the case of the correlation method, the same region is scanned a plurality of times, and a blood flow profile (blood flow direction, average flow) as a CFM image is obtained based on the correlation between the plurality of received signals. Flow velocity, degree of flow velocity dispersion, power in blood flow direction, etc.)
Are displayed at the levels of luminance, hue, and color tone. The DF mode display is usually used together with the M mode display and the B mode display, and is called an MDF mode display and a BDF mode display.

On the other hand, as already described in the section of the prior art, in an actual device, the PWD mode display is often applied to sector scanning due to the principle of the Doppler effect. This is because the use of the Doppler effect requires that the direction of the blood flow and the angle formed by the ultrasonic beam be non-orthogonal. At this point, sector scanning obliquely moves the ultrasonic beam. Because of this, application is easy. However, since the B-mode display image obtained by sector scanning has a sector shape, image observation is not performed as compared with a square image or a trapezoidal image obtained by trapezoidal scanning, such as a B-mode display image obtained by linear scanning. It is a leap thing.

Therefore, to approximate, the inventor uses a linear scanning probe to perform oblique linear scanning at a desired deflection angle with respect to D-mode display in order to obtain a B-mode display image by linear scanning for easy image observation. It was investigated.

In the apparatus at the examination stage in this examination, for example, a deflection angle setting knob is provided on the console, and by turning this knob clockwise or counterclockwise, the deflection angle can be set. Further, a sample point setting means for setting a sample point is provided on the console. Then, linear scanning for normal B-mode display and scanning for PWD mode display under the set deflection angle are performed for each ultrasonic raster, and B-mode display data and PWD mode display data are obtained. And got to get.

It has been found that an ultrasonic diagnostic apparatus that performs oblique linear scanning at a desired deflection angle with respect to D mode display using such a linear scanning probe has the following problems.

That is, the oblique linear scanning is realized in the ultrasonic transmission and reception system by selecting a group of transducers to be transmitted and received including the aperture of the transducer to be transmitted and received, and setting a delay amount for each element of the selected transducer group, Since the setting of the sample point is realized by the Doppler signal processing system,
Initially set a certain deflection angle and a certain sample point, and then PWD based on ultrasonic beams from different directions
When the deflection angle is changed to obtain blood flow velocity information as information,
The position of the sample point in the living body in the ultrasonic wave transmitting / receiving space changes. This is exactly because the sample point is determined by the beam propagation distance from the ultrasonic transmission / reception point.

This is shown in FIG. That is, the group of pulsed Doppler driving transducers (SDTG) is fixed, and initially transmitted and received by the transducers at the deflection angle θ1 (θ1 = 90 °), and the position of the sample point at the ultrasonic wave propagation distance d is set to SP1. Suppose you have set it. When transmission and reception are performed with the same transducer group (SDTG) at the deflection angle θ2, the ultrasonic wave propagation distance d does not change, so the position of the sample point is SP2.
become. Similarly, the same transducer group (SD
TG), since the ultrasonic wave propagation distance d does not change, the position of the sample point is SP3.

Therefore, the PWD mode display image (blood flow velocity data) obtained together with the B mode display image is different for each deflection angle, and it has been impossible to make an accurate diagnosis. Also, in order to prevent such a situation from occurring, it is necessary to perform an operation for redoing the setting so that the sample point is set at the same position every time the deflection angle is changed, which is very complicated. I will.

Therefore, when performing the PWD mode display by linear scanning, even if the deflection angle changes, the blood flow velocity information is automatically obtained as the PWD information at the same position, so that the operation is easy and high-precision diagnosis is performed. Techniques have been developed for this.

Here, as shown in FIG. 2, the sample point when the deflection angle θ2 is 90 ° is d (corresponding to the ultrasonic wave propagation distance), and the sample point is set at the same position even if the deflection angle changes. , An arbitrary deflection angle θ1
The sample point on the ultrasonic beam at d / cos
becomes α. Then, it can be seen that the transducer group may be shifted by d · tanα (vibrator selection control).

Therefore, as shown in FIG. 3, the blood flow velocity information as PWD information from the same sample point SP existing in the ultrasonic wave transmitting and receiving space is converted to an arbitrary deflection angle θ1 (beam propagation distance d).
1), deflection angle θ2 (beam propagation distance d2), deflection angle θ3
(Beam propagation distance d3).

According to this method, the blood flow velocity information as the PWD information obtained together with the B-mode image is obtained from the sample point SP at the same position even if the deflection angle changes, and an accurate diagnosis can be performed. There is. Further, it is not necessary to perform an operation for redoing the setting so that the sample point is set at the same position every time the deflection angle is changed. Only the initial setting is required, and the operability is good. Improvement is achieved.

Next, an embodiment of an ultrasonic diagnostic apparatus according to the present invention capable of performing the above-described technique will be described with reference to FIG.

As shown in FIG. 1, a linear scanning probe 10 in which ultrasonic transducer groups for N channels in the form of small strips are arranged in an array is applied to a body surface of a subject (not shown). The linear scanning probe 10 is driven to be transmitted by an ultrasonic transmission system 20 and is driven to be received by an ultrasonic reception system 30.

Here, the ultrasonic transmission system 20 is an ultrasonic linear probe 10
A transmission / reception transducer switch 22 for performing transmission / reception switching, an n (<N) channel pulsar 24 for applying an excitation pulse to each of the transducers selected for transmission by the transmission / reception transducer switching switch 22, The transmission delay controller 26 shifts the pulse application timing for each transducer according to the beam diameter, deflection angle, focus depth, and the like.

The ultrasonic receiving system 30 includes an n-channel preamplifier 32 that amplifies a reception echo signal due to reflected ultrasonic waves received by each transducer of the ultrasonic linear probe 10 that is selected by the transmission / reception transducer switch 22. An n-channel reception delay line 34 for delaying and adding the amplified signal output from each of the vibrators according to the aperture, the deflection angle, the focus depth, and the like, and a reception delay that is provided to the reception delay line 34 and provides delay data. And a controller 36.

The transmission delay controller 26 of the ultrasonic transmission system 20 and the reception delay controller 36 of the ultrasonic reception system 30 are under the control of a system control circuit 40, and the system control circuit 40 includes a PWD mode processing system 60 described later. Based on the sample point, generation of an ultrasonic rate related to transmission / reception timing and setting of a transmission delay time and a reception delay time corresponding to the aperture, the deflection angle, and the focus depth are performed.

On the other hand, as a B-mode image detection system, there is an envelope detector 50 that performs envelope detection of the added echo signal.

The D mode (PWD mode) processing system 60 performs phase detection on the added echo data relating to the ultrasonic transmission and reception in the Doppler mode,
A pulse Doppler detector 62 that obtains a Doppler signal for a sample point portion described later from the detection output, a sample circuit 64, and a frequency analysis is performed on the output of the pulse Doppler detector 62 by a fast Fourier transform (FFT) method to perform blood analysis. A frequency analysis circuit 66 for obtaining flow velocity data.

The CFM arithmetic unit 70 as the DF mode processing system scans the same portion a plurality of times, for example, in the case of the correlation method, and performs a blood flow as a CFM image based on the correlation between the plurality of received signals. It is possible to obtain CFM data that displays the profile (blood flow direction, average flow velocity, flow velocity dispersion degree, power in the blood flow direction, etc.) at the level of luminance, hue, and color tone.

The display system 80 stores the detection output of the envelope detector 50, the blood flow velocity data from the Doppler mode processing system 60, and the output from the CFM arithmetic unit 70 for each ultrasonic raster, and converts these into an ultrasonic raster. By making them compatible, a plurality of ultrasonic rasters having B-mode image data, blood flow velocity data, and CFM data are created, and this is used to form an ultrasonic image in frame units and convert it to a standard TV scan DSC (digital -Scan converter (82) and DAC (Digital-to-Analog converter) 8 that converts the output of this DSC82 to an analog signal
4 and control output signal added to DAC84 output
And a TV monitor 86 that performs display by TV scanning.

Here, the data writing control to the DSC 82 is performed by the system control circuit 40, and the system control circuit 40 performs the delay control based on the sample point related to the ultrasonic transmission and reception as described above. The CPU 90 receives a scan mode setting device 102, a deflection angle setting device 104, and a sample point setting device.
106, a console 100 having a focus setting device 108 and the like. Here, a scanning mode setting device 102, a deflection angle setting device 104, a sample point setting device 106,
The focus setting device 108 includes a plurality of switches, dial switches, and the like. Also, the CPU 90 gives a command to a GDC (Graphic Display Controller) 98 to generate a marker or the like indicating the sample point set by the console 100, and adds it to the output of the DSC 82 described above. I have.

In the B mode and the DF mode, a normal linear scan (deflection angle θ = 90 °) is performed by the control system including the console 100, the CPU 90, and the system control circuit 40 based on the principle of setting the positions of the sample points as described above. ) And the deflection angle setting device 104 provided on the console 100 can set oblique linear scanning with an arbitrary value of the deflection angle θ according to the operator's desire.
It is assumed that an arbitrary value of the deflection angle θ can be set by a deflection angle setting device 104 provided on the console 100 if desired by the operator, and a sample point is set at an arbitrary position by a sample point setting device 106 provided on the console 100. Can be set, and a B mode, a DF mode, and a D mode are set by a focus setting device 108 provided on the console 100.
One or more stages of focus can be set to arbitrary depths for each mode.

In this case, the position of the sample point is fixed, and as shown in FIG. 3, the selection of the transducer group and the beam deflection angle under the selection are performed so that the ultrasonic beam rotates around the position. The settings are made.

Next, the operation of the present embodiment configured as described above will be described. That is, as shown in FIG. 5, in step 1, the operator operates the preset switch provided on the console 100 to initialize the apparatus.

Next, in step 2, the operator sets a deflection angle setting device.
By operating 104, the deflection angle θ is set. In this step, in addition to this, for example, the depth of the one-step focus is set to be close to the SP shown in FIG. 6A, and the position of the sample point is also set to be the SP shown in FIG. 6A. (Deflection angle 90 °), and the deflection angle is set to a desired value by the deflection angle setting unit 104 only in the D mode. Thereby, the focus and the sample point are fixed to the SP.

Next, in step 3, the CPU 90 calculates, by calculating, the center vibrator of the group of simultaneous driving vibrators to obtain the propagation path of the ultrasonic beam under the deflection angle θ. Calculation is performed to shift the sound beam to a position where it intersects the transducer surface of the probe 10, that is, a position that is an equivalent sound source of the probe 10.

Here, as shown in FIG. 2, the position where the center oscillator of the group of simultaneously driven ultrasonic transducers is shifted is e _c ′, the position of the center element of the probe 10 is e _c , and e _c and If the distance between SP and d is e, the distance between e _c 'and SP is d', and the angle between the line segment of distance d and the line segment of distance d 'is α, then The following relational expression holds.

e _c ′ = e _c −d tan α, d ′ = d / cos α Next, in step 4, the CPU 90 calculates the distance d of the ultrasonic beam propagation path under the deflection angle θ calculated by step 3. And a focus point and a sample point under the deflection angle θ are calculated by using the distance d ′.

Next, in step 5, the delay time of at least one of transmission and reception for having the deflection angle and the focus point set under the fixed SP is calculated,
By being given to the system control circuit 40,
The transmission delay controller 26 and the reception delay controller 36 are driven, and the probe 10 transmits and receives an ultrasonic beam having a deflection angle and a focus point under the fixed SP. Here, the delay time τ _i is as follows.

Here, a is the transducer pitch and c is the speed of sound.

In addition to this operation, scanning in the D mode based on the deflection angle θ based on the selection control and the delay amount control of the group of simultaneously driven transducers is performed, and normal scanning is performed in the B mode. Therefore, as shown in FIG. 3, the blood flow velocity information is used as the PWD information from the SP to convert the blood flow velocity information to an arbitrary deflection angle θ (the beam propagation distance is d1, d2, d3).
Under will be able to collect.

A timing chart showing the operation of the ultrasonic diagnostic apparatus is shown in FIGS. 7A to 7F. FIG. 7A is a timing chart of a rate pulse, in which one pulse indicates one ultrasonic transmission / reception. FIG. 7B is a timing chart of the raster address, where 0, 1, 2,... Indicate the ultrasonic raster numbers in the B mode, and D indicates that the raster is in the D mode. FIG. 7C is a timing chart of the sampling time for the B mode, and shows the sampling timing for forming the ultrasonic rasters 0, 1, 2,... In the B mode. FIG. 7D is a timing chart for data input in the CFM operation processing (DF mode), and shows data input timings for creating ultrasonic rasters 0, 1, 2,... In the BDF mode. FIG. 7E is a timing chart for data output in the CFM operation processing (DF mode), and shows data output timings for generating ultrasonic rasters 0, 1,... In the BDF mode. FIG. 7F is a timing chart of a sampling time for the PWD mode (D mode).

According to the above, the blood flow velocity information as the PWD information obtained together with the B-mode image is obtained from the same position SP even when the deflection angle changes, and there is an advantage that an accurate diagnosis can be performed. Also, unlike the conventional method, it is not necessary to perform an operation for redoing the setting so that the sample point is set at the same position each time the deflection angle is changed. Becomes

In the above-mentioned B mode or BDF mode, it is assumed that the normal scanning is performed with the deflection angle θ = 90 °. However, as shown in FIG. 6B, the B mode or BDF mode and the D mode have the same deflection. Oblique linear scanning at angles θ1 and θ2 (θ1 = θ2) may be performed. Further, as shown in FIG. 6C, the B mode or BDF mode and the D mode are set to different deflection angles θ1, θ2.
Oblique linear scanning of (θ1 ≠ θ2) may be performed.

Here, an example of mode combinations will be described. That is, B
Example of performing mode oblique linear scanning and D mode oblique scanning,
Example of performing B-mode linear scanning and D-mode oblique scanning;
There are examples in which mode oblique linear scanning, D mode oblique scanning, and D mode oblique DF mode scanning are performed, and examples in which B mode linear scanning, D mode oblique scanning, and D mode oblique DF mode scanning are performed. Here, the D mode scanning is typically a PWD mode scanning.

In the above example, when the sample point is set, the control elements of the ultrasonic transmission / reception system (vibrator group selection control including aperture control, delay amount control, focus control) are determined based on the setting. Among the control elements of the transmission / reception system, the vibrator group selection control including the aperture control and the delay amount control may be determined, and the focus control may be adjustable.

As described above, according to the present embodiment, the deflection angle setting unit 104 that sets the deflection angle in oblique linear scanning, and the D mode (P
By operating the sample point setting device 106 for setting the sample point in the WD mode) and the deflection angle setting device 104, the position of the sample point in the living body is kept constant even when the deflection angle changes. Since it is possible to perform control such as at least one of transducer selection control, delay amount control, and focus control including transducer aperture control in oblique linear scanning, when a certain sample point is initially set, the position of this sample point Is maintained, vibrator selection control including vibrator aperture control, delay amount control, and focus control are performed so as to perform oblique linear scanning at a desired deflection angle in the D (PWD mode) mode. Therefore, even if the deflection angle changes, the PW at the same position
The blood flow velocity information is automatically obtained as the D information, which has an effect that the operation is facilitated and a highly accurate diagnosis can be performed.

In addition, the setting of the deflection angle of the ultrasonic beam in the D-mode scanning can be in a mode as shown in FIGS. 8A to 8D. For example, as shown in FIGS. 8A and 8B, an example in which a limit is applied at the end of the linear scanning probe, and an example in which a return is applied at the end of the linear scanning probe as shown in FIGS. 8C and 8D. is there. These include adding a limiter or return setting device to the deflection angle setting device, or the equivalent sound source of the ultrasonic beam is located at the end of the linear scanning probe.
This is realized by a configuration that the CPU 90 obtains by calculation.

The absolute flow velocity value V can be measured by utilizing the fact that a plurality of deflection angles can be easily set by operating the deflection angle setting device. The principle is described below with reference to FIGS.
This will be described with reference to FIG.

As shown in FIG. 9, by operating the deflection angle setting device, the beam 1 and the beam 2 are transmitted and received at the illustrated angles β1 and β2 in the D mode. In this case, beam 1 and beam 2 transmit and receive alternately according to the rate pulse.

Then, the Doppler shift frequency fd1 at the sample point of beam 1 is as follows.

The Doppler shift frequency fd2 at the sample point of the beam 2 is as follows.

When h = 2f _0, When fd1 = hVcosβ1 fd2 = hVcosβ2 a = fd1 / h, b = fd2 / h, V, a, the relationship b is as shown in Figure 10.

Here, ΔACB, ΔADB, ΔACE, and ΔADE are right triangles, and AE = b / cosβ and DE = ab−cosβ.

DB = DE / tanβ = (ab / cosβ) / tanβ = acotβ−b / sinβ Therefore, for ΔACB, from the relation AB ² = AD ² + DB ² , An apparatus embodying the above principle is shown in FIGS. 11A and 11B.

The configuration of FIG. 11A is such that the output from the PWD detector 72 is input to a frequency analyzer 77-1 for obtaining the Doppler shift frequency fd1 at the sample point of the beam 1, and the Doppler shift at the sample point of the beam 2 The frequency fd2 is input to a frequency analyzer 77-2 for obtaining the frequency fd2.
The values fd1 and fd2 obtained in 1,77-2 are supplied to an absolute flow velocity calculator 78, where V is calculated.

The configuration shown in FIG. 11B is different from the configuration shown in FIG. 11B in that the outputs of the beam 1 and the beam 2 from the PWD detector 72 are alternately input to the frequency analyzer 77 and are alternately obtained as fd1 and fd2. ,
Fd held in memory 79-1 and 79-2
1, fd2 is given to an absolute flow velocity calculator 78, where V is calculated.

As described above, according to the present invention, at least one of the transducer selection control including the transducer aperture control in the oblique linear operation, the delay amount control, and the focus control is performed so that the position of the sample point in the living body is constant. Since the blood flow velocity information is automatically obtained as PWD information at the same position even if the deflection angle changes, the operation can be easily performed and highly accurate diagnosis can be performed. This has the effect.

In addition, various modifications can be made without departing from the scope of the present invention.

[Effects of the Invention] As described above, according to the present invention, a transmission / reception unit that linearly scans an ultrasonic beam transmitted / received from a linear scanning probe to a subject, and propagation of the ultrasonic beam as desired by an operator. Sample point setting means for setting a sample point at an arbitrary position on a road; deflection angle setting means for setting a deflection angle of the ultrasonic beam to an arbitrary value as desired by an operator; When the deflection angle is reset by the means, the position of the sample point already set on the subject is fixed,
Changing means for changing a set value of the sample point setting means so that a position of the fixed sample point becomes a sample point of the ultrasonic beam under the reset deflection angle; And a video system having at least a D-mode processor for calculating the Doppler shift frequency fd by calculating the Doppler shift frequency fd by calculating the Doppler shift frequency fd and calculating the blood flow rate information of the subject from the Doppler shift frequency fd. Initially, when a certain sample point is set, the position of this sample point is not changed, and a transducer selection control including a transducer aperture control is performed so that an oblique linear scan at a desired swing angle in the Doppler mode is performed. The delay amount control and the focus control are performed. Therefore, even if the swing angle is changed, Doppler information at the same position is automatically obtained, and there is an effect that the operation is facilitated and a highly accurate diagnosis can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing that the position of the sample point changes when the deflection angle of the ultrasonic beam in linear scanning is changed, and FIG. 2 is a diagram showing the sample point, the deflection angle of the ultrasonic beam and the propagation path in linear scanning. Diagram showing the relationship,
FIG. 3 is a diagram showing changes in the deflection angle and propagation path of an ultrasonic beam when a sample point in linear scanning is fixed, and FIG. 4 is an embodiment of an electronic linear scanning type ultrasonic diagnostic apparatus according to the present invention. FIG. 5 is a block diagram showing the configuration of the example, FIG. 5 is a flowchart showing the operation of the ultrasonic diagnostic apparatus shown in FIG. 4, and the operating procedure of the operator. FIGS. 6A to 6C are deflection angles of the ultrasonic beam for B-mode scanning. FIG. 6B is a diagram showing an example of the combination of D and the deflection angle of the ultrasonic beam for D-mode scanning,
In the figure, the deflection angle of the ultrasonic beam in the B-mode scanning is different from the deflection angle of the ultrasonic beam in the D-mode scanning, the deflection angle of the ultrasonic beam in the B-mode scanning is 90 °, and the FIG. 6B shows a case where the deflection angle of the sound beam is non-90 °, and FIG.
FIG. 6C shows a case where the deflection angle of the ultrasonic beam for mode scanning is the same and the deflection angle is both non-90 °, and FIG. 6C shows the deflection angle of the ultrasonic beam for B mode scanning and the ultrasonic wave for D mode scanning. FIG. 13 is a diagram showing a case where the deflection angle of the beam is different from the deflection angle of the ultrasonic beam for B-mode scanning is non-90 ° and the deflection angle of the ultrasonic beam for D-mode scanning is also non-90 °;
7A to 7F are timing charts showing the operation of the ultrasonic diagnostic apparatus shown in FIG. 4, FIG. 7A is a timing chart of a rate pulse, FIG. 7B is a timing chart of a raster address, and FIG. Timing chart of sampling time for B mode, Fig. 7D is timing chart for data input of CFM operation processing (DF mode), Fig. 7E is timing chart for data output of CFM operation processing (DF mode) FIG. 7F is a timing chart of a sampling time for the PWD mode (D mode), and FIGS. 8A to 8D are diagrams showing setting modes of the deflection angle of the ultrasonic beam in the D mode scanning. Figures and No.
8B is a diagram showing an example in which a limit is applied at the end of the linear scanning probe, FIGS. 8C and 8D are diagrams showing an example in which a return is applied at the end of the linear scanning probe, and FIG. Diagram showing the principle of measuring the absolute flow velocity value using two ultrasonic beams, FIG. 10 is a diagram geometrically showing the principle of measuring the absolute flow velocity value, and FIG. 11A is a configuration for measuring the absolute flow velocity value 11B is a block diagram of the first embodiment, and FIG. 11B is a block diagram of the second embodiment according to the configuration for measuring the absolute flow velocity value. 10 ... Linear scanning probe, 20 ... Ultrasonic transmission system, 22
… Transmitter / receiver selector switch, 24… Pulsa, 26…
Transmission delay control circuit, 30 ... Ultrasonic reception system, 32 ...
... preamplifier, 34 ... reception delay line, 36 ... reception delay control circuit, 40 ... system control circuit, 50 ...
... Envelope detector, 60 ... D-mode processing system, 62 ... Pulse Doppler detector, 64 ... Sample circuit, 66 ... Frequency analysis circuit, 70 ... CFM calculator, 80 ... Display system, 82 ... DSC, 84
…… DAC, 86 …… Display, 88 …… GDC, 90 …… CP
U, 100: Console, 102: Scan mode setting device, 104
…… Deflection angle setting device, 106 …… Sample point setting device, 1
08 ... Focus setting device.

Claims (1)

(57) [Claims] 1. A transmission / reception unit for linearly scanning an ultrasonic beam transmitted / received to / from a subject from a linear scanning probe, and a sample point at an arbitrary position on a propagation path of the ultrasonic beam as desired by an operator. Sample point setting means for setting the deflection angle, a deflection angle setting means for setting the deflection angle of the ultrasonic beam to an arbitrary value as desired by the operator, and the deflection angle is reset by the deflection angle setting means. At this time, the position of the sample point already set on the subject is fixed, and the position of the fixed sample point is changed to the sample point of the ultrasonic beam under the reset deflection angle. Changing means for changing the set value of the sample point setting means so that the frequency of the received signal at the sample point is analyzed and Doppler polarization Determined frequency fd, the ultrasonic diagnostic apparatus characterized by comprising a video system with the at least a D-mode processor for calculating a blood flow velocity information of the subject from the Doppler shift frequency fd.