JPH07328001A - Ultrasonic bloodstream image generating method and ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To remove the clutter constituent even when the frequency band of the clutter constituent and the frequency band of the bloodstream constituent are overlapped or proximately located. CONSTITUTION:The sound ray data read out from memories 6, 7 at the first time are inputted to an autocorrelation computation section 12 not through MTI filters 10, 11. The autocorrelation computation section 12 calculates the flow information at each observation point on one sound ray and sends it to a judgment section 14. The judgment section 14 judges whether each observation point is a flow portion or a structural portion based on the flow information at each observation point and writes the judged result on a register 15. The sound ray data read out from the memories 6, 7 at the second time are inputted to the MTI filters 10, 11, and the data are inputted to the autocorrelation computation section 12 after the low-frequency constituent is removed by the MTI filters 10, 11. The autocorrelation computation section 12 calculates the flow information at each observation point on one sound ray and sends it to an elimination section 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic blood flow image generation method and an ultrasonic diagnostic apparatus, and more specifically, to a motion artifact (Mot) caused by the movement of an organ or the like.
TECHNICAL FIELD The present invention relates to an ultrasonic blood flow image generation method and an ultrasonic diagnostic apparatus capable of reducing ion artifacts.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram of an ultrasonic Doppler diagnostic apparatus 500 disclosed in Japanese Patent Laid-Open No. 5-7588.
In this ultrasonic Doppler diagnostic apparatus 500, the ultrasonic probe 1 and the transmission / reception unit 2 scan the subject with sound rays, collect ultrasonic echoes from a large number of observation points on each sound ray, and collect each sound. An ultrasonic echo signal for each line is output. The quadrature detection unit 3 multiplies a reference signal from a reference signal generator (not shown) by the ultrasonic echo signal to generate sound ray data Q,
I (Q: quadrature signal, I: in-phase signal) is output. A / D
The converters 4 and 5 convert the sound ray data Q and I into digital values and pass them to MTI (Moving Target Indication) filters 10 and 11. The MTI filters 10 and 11 are
The low frequency components of the sound ray data are cut. The first autocorrelation etc. computing unit 12 uses the MTI filters 10, 1
The velocity and / or dispersion of the flow at each observation point is calculated from the sound ray data passing through 1. DSC (Digital Scan C)
The onvertor 17 generates a blood flow image based on the position of each observation point on the whole sound ray in the scanning area and the velocity and / or dispersion. This blood flow image is displayed on the CRT monitor 18. On the other hand, the A / D converters 4 and 5 generate the sound ray data Q,
I is converted into a digital value, and the second autocorrelation etc. computing unit 19
Pass it on. The second autocorrelation etc. computing unit 19 uses the MTI.
The velocity and / or variance of the flow at each observation point is calculated from the sound ray data that does not pass through the filters 10 and 11, and the clutter component (the velocity component due to the movement of the organ) is removed from the velocity and / or the variance of the flow. The filter characteristic for performing the above is obtained, and the filter characteristic is stored in the filter characteristic memory 20. The filter characteristic memory 20 gives the filter characteristic to the MTI filters 10 and 11.

Therefore, as shown in FIG. 5, when there is a clutter component C and a blood flow component B, and a filter characteristic H is given, only the clutter component C is removed by the MTI filters 10 and 11, so that motion is detected. A blood flow image without artifacts will be obtained.

[0004]

In the conventional ultrasonic Doppler diagnostic apparatus 500, the MTI filters 10 and 11 remove clutter components in the frequency domain. When the clutter component C and the blood flow component B are in separate frequency bands as shown in FIG. 5, this allows the clutter component to be successfully removed. However, as shown in FIG. 6, when the frequency band of the clutter component C and the frequency band of the blood flow component B overlap, the clutter component cannot be removed, and there is a problem that motion artifacts appear. When the frequency bands of the clutter component C and the blood flow component B are close to each other,
It becomes impossible to determine an appropriate filter characteristic, and there is a problem that motion artifacts still appear. Therefore, an object of the present invention is to eliminate the clutter component and reduce motion artifacts even when the frequency band of the clutter component C and the frequency band of the blood flow component B overlap or are close to each other. An object is to provide an ultrasonic blood flow image generation method and an ultrasonic diagnostic apparatus.

[0005]

In a first aspect, the present invention acquires sound ray data from ultrasonic echoes from a large number of observation points on each sound ray scanned by a subject, and the sound ray data is obtained. Flow information including at least one of velocity, power or dispersion of flow at each observation point on one sound ray is calculated from
In an ultrasonic blood flow image generation method that generates a blood flow image based on the position and flow information of each observation point in the scanning region, whether each observation point is a flow part based on the flow information of each observation point on one sound ray. Provide an ultrasonic blood flow image generation method characterized in that it is determined whether it is a structural portion, the flow information of the flow portion is used for generating the blood flow image, and the flow information of the structural portion is not used for generating the blood flow image To do.

According to a second aspect, the present invention obtains sound ray data from ultrasonic echoes from a large number of observation points on each sound ray scanned by a subject, and obtains one sound ray from the sound ray data. Ultrasonic diagnosis that calculates flow information including at least one of flow velocity, power, or dispersion at each observation point, and generates and displays a blood flow image from the position and flow information of each observation point in the scanning region. In the device, a determination means for determining whether each observation point is a flow portion or a structural portion based on the flow information of each observation point on one sound ray, and the flow information of the flow portion can be used for generating a blood flow image. An ultrasonic diagnostic apparatus is provided, comprising: a removing unit that removes remaining flow information of a structural portion so that it cannot be used for generating a blood flow image.

According to a third aspect of the present invention, an ultrasonic wave transmitting / receiving means for scanning an object with a sound ray and collecting ultrasonic wave echoes from a large number of observation points on each sound ray, and a large number of ultrasonic rays on each sound ray. Sound ray data acquisition means for acquiring sound ray data from the ultrasonic echoes from the observation points, an MTI filter for cutting low frequency components of the sound ray data, and its MT.
First calculation means for calculating flow information including at least one of velocity, power or dispersion of flow at each observation point on one sound ray from the sound ray data which has passed through the I filter, and each observation point in the scanning region In the ultrasonic diagnostic apparatus having a blood flow image generation means for generating a blood flow image based on the position and flow information, and a display means for displaying the blood flow image, the MTI
Second calculation means for calculating the flow information at each observation point on one sound ray from the sound ray data before passing through the filter, and one based on the flow information at each observation point calculated by the second calculation means Determination means for determining whether each observation point on the sound ray is a flow portion or a structural portion; and flow information of the observation point determined to be a flow portion by the determination means among the flow information calculated by the first calculation means, and There is provided an ultrasonic diagnostic apparatus comprising: a removing unit that removes flow information of an observation point determined to be a structural portion.

According to a fourth aspect, in the ultrasonic diagnostic apparatus according to the third aspect, the present invention serves as both a memory for storing sound ray data and both the first computing means and the second computing means. The sound ray data read from the memory for the first time is input to the calculation means without passing through the MTI filter, and the sound ray data read for the second time from the memory is calculated by the MTI filter. Through the first switching means for inputting to the arithmetic means through the arithmetic means, and the flow information output from the arithmetic means for the first sound ray data is processed by the judging means and for the second sound ray data. An ultrasonic diagnostic apparatus is provided, comprising: a second switching unit that processes the flow information output from the computing unit by the removing unit.

According to a fifth aspect of the present invention, in the ultrasonic diagnostic apparatus according to the third aspect, the flow information of an observation point determined to be a flow portion by the determination means is replaced by the flow information of the observation point instead of the removal means. (EN) Provided is an ultrasonic diagnostic apparatus, characterized by comprising control means for calculating flow information of an observation point which is calculated by one calculation means and which is determined to be a structural portion, by the first calculation means.

According to a sixth aspect, in the ultrasonic diagnostic apparatus according to the fifth aspect, the present invention serves as both a memory for storing sound ray data and both the first computing means and the second computing means. The sound ray data read from the memory for the first time is input to the calculation means without passing through the MTI filter, and the sound ray data read for the second time from the memory is calculated by the MTI filter. Through the first switching means for inputting to the arithmetic means through the arithmetic means, and the flow information output from the arithmetic means for the first sound ray data is processed by the judging means and for the second sound ray data. The flow information output from the arithmetic means is provided with a second switching means for processing by the blood flow image generating means, and the control means stores it in the first reading from the memory. The line data is read as it is, and in the second reading from the memory, the data of the observation point determined to be the flow portion of the stored sound ray data is read as it is and the observation point determined to be the structural portion. The above data is replaced with dummy data to provide an ultrasonic diagnostic apparatus.

According to a seventh aspect, the present invention provides the ultrasonic diagnostic apparatus according to the fourth or sixth aspect, wherein the interval between the first read and the second read from the memory is the sound ray data. Provided is an ultrasonic diagnostic apparatus characterized by being shorter than 1/2 of the acquisition cycle.

[0012]

In the ultrasonic blood flow image generating method and the ultrasonic image diagnostic apparatus of the present invention, first, based on the flow information (at least one of velocity, power or dispersion of flow) of each observation point on one sound ray. , Determine whether each observation point is a flow part or a structure part. Next, the flow information of the observation point that is determined to be the flow portion of each observation point on one sound ray is used to generate the blood flow image, and the flow information of the observation point that is determined to be the structural portion is used to generate the blood flow image. Do not use for. In this way, the clutter component is removed not by removing the clutter component in the frequency domain but by removing the flow information at the observation point that is determined to be the structural part, so the frequency band of the clutter component and the frequency band of the blood flow component are removed. Even if and are overlapping or close to each other,
Clutter components can be removed and motion artifacts can be reduced.

The ultrasonic diagnostic imaging apparatus according to the third aspect calculates flow information regardless of whether it is a flow portion or a structure portion, but discards the flow information at the observation point of the structure portion. On the other hand, the ultrasonic diagnostic imaging apparatus according to the fifth aspect described above calculates the flow information of the observation points of the flow portion, but does not calculate the flow information of the observation points of the structural portion.

In the ultrasonic diagnostic imaging apparatus according to the fourth and sixth aspects, one computing means is shared by the computing means for the determination and the computing means for the blood flow image. . In the ultrasonic diagnostic imaging apparatus according to the seventh aspect, the calculation for determination and the calculation for blood flow image are performed within the acquisition period of the sound ray data, and one calculation means is shared. Even in the case, the processing is not delayed.

[0015]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. The present invention is not limited to this.

First Embodiment FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus 1000 including the ultrasonic Doppler diagnostic apparatus 100 of the first embodiment. In this ultrasonic diagnostic apparatus 1000, the ultrasonic probe 1 and the transmission / reception unit 2 scan the subject with sound rays, collect ultrasonic echoes from a large number of observation points on each sound ray, and detect each sound ray. An ultrasonic echo signal for each is output. This ultrasonic echo signal is input to the quadrature detection unit 3 and the B mode processing unit 23 of the ultrasonic Doppler diagnostic apparatus 100.

The quadrature detection section 3 of the ultrasonic Doppler diagnostic apparatus 100 multiplies a reference signal from a reference signal generator (not shown) by the ultrasonic echo signal to obtain sound ray data Q, I.
(Q: quadrature signal, I: in-phase signal) is output. The A / D converters 4 and 5 convert the sound ray data Q and I into digital values and store them in memories 6 and 7, respectively.

From the memories 6 and 7, the sound ray data Q,
When I is read for the first time, the changeover switches 8 and 9 are
The read sound ray data Q and I are transferred to the MTI filter 10,
The value is input to the autocorrelation calculation unit 12 without passing through 11. The autocorrelation calculation unit 12 calculates flow information including at least one of flow velocity, power, or dispersion at each observation point from the sound ray data input without passing through the MTI filters 10 and 11. The flow information calculated by the autocorrelation calculation unit 12 from the sound ray data input without passing through the MTI filters 10 and 11 is not input to the removal unit 16 but input to the determination unit 14 by the changeover switch 13. It

The determination unit 14 stores the determination rule as shown in the following example, which is experimentally and empirically determined. If the velocity is below a predetermined threshold velocity, the observer is a tissue part. If the power is greater than the predetermined threshold power, the observation point is a tissue part. If the variance is less than the predetermined threshold variance, then the observer is a tissue part. If the velocity is lower than the predetermined velocity and the power is higher than the predetermined power, the observation point is the tissue portion. If the observation point is not a tissue part, it is a flow part. The determination unit 14 determines whether each observation point on the sound ray is a flow portion or a tissue portion based on the above determination rule, and as shown in FIG. Then, "1" is written in the register 15 and "0" is written in the register 15 for the observation point determined as the tissue portion. When this writing is completed, the sound ray data Q and I are read from the memories 6 and 7 for the second time. Since the above determination rule considers elements other than velocity, even if the frequency band of the clutter component and the frequency band of the blood flow component overlap or are close to each other, the flow portion and the tissue portion are not separated. It can be judged properly.

From the memories 6 and 7, the sound ray data Q,
When I is read for the second time, the changeover switches 8 and 9 are
The read acoustic line data Q and I are used to calculate the autocorrelation calculation unit 12
It is input to the MTI filters 10 and 11 without being input to. M
The TI filters 10 and 11 cut the low frequency components of the sound ray data and then pass the sound ray data to the autocorrelation calculation unit 12. The auto-correlation calculation unit 12 calculates flow information including at least one of flow velocity, power, and dispersion at each observation point from the sound ray data passed from the MTI filters 10 and 11. The changeover switch 13 determines the flow information calculated by the autocorrelation calculating unit 12 from the sound ray data input through the MTI filters 10 and 11 to the judging unit 1.
Instead of inputting to 4, it is input to the removing unit 16. The removal unit 16
Is the flow information at the same observation point and the register 15
Is multiplied by the value written in and the result of the multiplication is passed to the DSC 17 as flow information. As a result, the flow information of the observation point of the flow portion is input to the DSC 17 as it is, and the flow information of the observation point of the structure portion is set to "0" and input to the DSC 17.

The DSC 17 generates a blood flow image based on the position of each observation point on all sound lines in the scanning area and the flow information. Since the removal unit 16 sets the flow information of the observation points of the structure portion to "0", the blood flow image has reduced motion artifacts. The CRT monitor 18 displays the blood flow image.

The B-mode processing unit 23 processes the ultrasonic echo signal to generate B-mode data, and the DSC 17
Pass to. The DSC 17 generates a B-mode image from the B-mode data. The CRT monitor 18 displays the B-mode image.

According to the ultrasonic diagnostic apparatus 1000 described above, the clutter component is removed in the frequency domain by removing the clutter component by removing the flow information of the observation point determined as the structural portion, instead of removing the clutter component. Even when the frequency band and the frequency band of the blood flow component overlap or are close to each other, the clutter component can be removed and the motion artifact can be reduced.

When the calculation for determination and the calculation for blood flow image are performed by one autocorrelation calculation unit 12 as described above, the memory 6 is operated within a normal sound ray data acquisition cycle. , 7, it is preferable to determine the processing speed of the autocorrelation calculation unit 12 and the like so that the reading can be performed twice. on the other hand,
If the calculation for the determination and the calculation for the blood flow image are performed by different calculation units, if the calculation timing for the blood flow image is slightly delayed from the calculation timing for the determination, It is only necessary to read from the memories 6 and 7 once.

Second Embodiment FIG. 3 is a block diagram of the ultrasonic Doppler diagnostic apparatus 101 according to the second embodiment. The ultrasonic Doppler diagnostic apparatus 101 has a data read control unit 26 instead of the removing unit 16 in the ultrasonic Doppler diagnostic apparatus 100 of the first embodiment.
The data read control unit 26 permits the read as it is when the value written in the register 15 at a certain observation point is “1” at the time of the second read of the sound ray data from the memories 6 and 7. If the value written in the register 15 is "0", "0" is forcibly read. In the ultrasonic Doppler diagnostic apparatus 101, since the data of the observation point of the structural portion is forcibly set to “0”, the flow information of the observation point of the structural portion is substantially removed. Therefore, the clutter component is removed, and the motion artifact is reduced.

[0026]

According to the ultrasonic blood flow image generating method and the ultrasonic diagnostic apparatus of the present invention, the clutter component is not removed in the frequency domain, but the flow information of the observation point determined as the structural portion is removed. Since the clutter component is removed by the method, the clutter component can be removed even when the frequency band of the clutter component and the frequency band of the blood flow component overlap or are close to each other, and motion artifacts can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the principle of the present invention.

FIG. 3 is a block diagram of an ultrasonic Doppler diagnostic apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a block diagram of an example of a conventional ultrasonic Doppler diagnostic apparatus.

5 is an explanatory view of the principle of the conventional device of FIG.

6 is an explanatory diagram of a problem in the conventional device of FIG.

[Explanation of symbols]

 1000 Ultrasound Diagnostic Device 100, 101 Ultrasound Doppler Diagnostic Device 6, 7 Memory 8, 9, 13 Changeover Switch 10, 11 MTI Filter 12 Autocorrelation Computation Unit 14 Judgment Unit 15 Register 16 Removal Unit 17 DSC 18 CRT Monitor 23 B Mode processing unit 26 Data reading control unit

Claims (7)

[Claims] 1. Sound velocity data obtained from ultrasonic echoes from a large number of observation points on each sound ray scanned on a subject, and the velocity of the flow at each observation point on one sound ray from the sound ray data. , An ultrasonic blood flow image generation method for calculating a flow information including at least one of power or dispersion and generating a blood flow image based on the position of each observation point in the scanning region and the flow information. Based on the flow information of each observation point, it is determined whether each observation point is a flow part or a structure part, the flow information of the flow part is used to generate a blood flow image, and the flow information of the structure part is used to generate a blood flow image. An ultrasonic blood flow image generation method characterized by not using. 2. The velocity of the flow at each observation point on one sound ray is obtained from the acoustic ray data obtained from ultrasonic echoes from a large number of observation points on each sound ray scanned by the subject. , An ultrasonic diagnostic apparatus that calculates flow information including at least one of power and dispersion, and generates and displays a blood flow image based on the position and flow information of each observation point in the scanning region. A determination unit that determines whether each observation point is a flow portion or a structure portion based on the flow information of each observation point, and the flow information of the flow portion is left so that it can be used to generate a blood flow image, and the flow information of the structure portion is An ultrasonic diagnostic apparatus, comprising: a removing unit that removes the bloodstream image so that it cannot be used for generation. 3. Ultrasonic transmission / reception means for scanning an object with sound rays and collecting ultrasonic echoes from a large number of observation points on each sound ray, and ultrasonic echoes from a large number of observation points on each sound ray. Sound ray data obtaining means for obtaining more sound ray data, and M for cutting low frequency components of the sound ray data
A TI filter, first calculation means for calculating flow information including at least one of velocity, power or dispersion of flow at each observation point on one sound ray from sound ray data that has passed through the MTI filter, and a scanning area Blood flow image generation means for generating a blood flow image by the position and flow information of each observation point in the,
In an ultrasonic diagnostic apparatus having a display unit for displaying the blood flow image, a second arithmetic unit for calculating flow information at each observation point on one sound ray from the sound ray data before passing through the MTI filter, Determination means for determining whether each observation point on one sound ray is a flow portion or a structural portion based on the flow information of each observation point calculated by the second calculation means, and the flow information calculated by the first calculation means The ultrasonic diagnostic apparatus is characterized by further comprising: removing means for leaving the flow information of the observation point determined to be the flow portion by the determination means and removing the flow information of the observation point determined to be the structure portion. 4. The ultrasonic diagnostic apparatus according to claim 3, wherein the memory stores sound ray data, and a computing unit that serves as both the first computing unit and the second computing unit.
The sound ray data read from the memory for the first time is input to the calculation means without passing through the MTI filter, and the sound ray data read for the second time from the memory is passed through the MTI filter to the calculation means. First to enter
The switching means and the flow information output from the calculating means for the first sound ray data are processed by the determining means, and the flow information output from the calculating means for the second sound ray data. Is equipped with a second switching means for processing by the removing means. 5. The ultrasonic diagnostic apparatus according to claim 3, wherein, instead of said removing means, flow information of an observation point determined to be a flow portion by said determining means is calculated by said first calculating means and structured. An ultrasonic diagnostic apparatus comprising: a control unit that does not allow the first arithmetic unit to calculate the flow information of the observation points determined to be a part. 6. The ultrasonic diagnostic apparatus according to claim 5, further comprising: a memory for storing sound ray data; and a computing unit that serves as both the first computing unit and the second computing unit.
The sound ray data read from the memory for the first time is input to the calculation means without passing through the MTI filter, and the sound ray data read for the second time from the memory is passed through the MTI filter to the calculation means. First to enter
The switching means and the flow information output from the calculating means for the first sound ray data are processed by the determining means, and the flow information output from the calculating means for the second sound ray data. And a second switching unit for processing by the blood flow image generating unit, the control unit causes the stored sound ray data to be read as it is in the first reading from the memory, and The second reading is characterized in that the data of the observation point determined to be the flow portion of the stored sound ray data is read as it is, and the data of the observation point determined to be the structural portion is replaced with dummy data. Ultrasonic diagnostic equipment. 7. The ultrasonic diagnostic apparatus according to claim 4 or 6, wherein the interval between the first read and the second read from the memory is 1/2 of the acquisition period of the sound ray data. An ultrasonic diagnostic device characterized by being short.