JPH07178086A - Method for ultrasonic diagnosis and system therefor - Google Patents

Abstract

PURPOSE:To perform three-dimensional display of a blood vessel wall by determining a bloodstream distribution image of each slice of an examinee to be inspected from Doppler information of ultrasonic echo, extracting therefrom the blood vessel wall certainly, connecting correctly vessel walls together which belong to the same blood vessel for all slices. CONSTITUTION:A motion compensating circuit 22 compensates distortion due to motion of a bloodstream distribution image. A blood vessel wall extracting circuit 24 extracts the vessel wall in accordance with the degree of expansion of the flow speed distribution, in the case the blood vessel is thick and free of turbulent flow, and extracts the edge of the bloodstream distribution image as the vessel wall in the case the blood vessel is thin and free of turbulent flow or the one is with turbulence. A blood vessel wall connecting circuit 26 judges whether the vessel walls belong to the same vessel or the vessel is diverging or intersecting in accordance with the vessel diameter, flow speed, rate of flow, flow direction, intra-vessel speed change pattern, intra-vessel speed distribution, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic diagnostic method, and more particularly, it is for medical use in which blood flow information in a subject is obtained from Doppler information of ultrasonic echoes and displayed three-dimensionally. The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic diagnostic method.

[0002]

2. Description of the Related Art An ultrasonic wave is three-dimensionally scanned with respect to a subject, a blood flow distribution image of each slice of the subject is obtained from Doppler information of an ultrasonic echo, a blood vessel wall is extracted from the blood flow distribution image, and the same in all slices. An ultrasonic diagnostic apparatus has been developed which connects blood vessel walls belonging to a blood vessel and displays the blood vessel wall three-dimensionally.

In such an apparatus, first, a predetermined slice is set, and ultrasonic pulses are transmitted and received for a fixed time for each raster (scanning line) as in the case of displaying a normal two-dimensional blood flow distribution image. Then, the phase change of the reflected ultrasonic echo based on the Doppler effect is detected, and blood flow information at each depth position on the scanning line is obtained. A two-dimensional blood flow distribution image is obtained by scanning this scanning line within the slice. This blood flow distribution image information is stored in image storage means such as a magneto-optical disk device.
Then, a blood flow distribution image is similarly obtained while slightly shifting the slice position, a blood flow distribution image for a plurality of slices is created, and blood flow distribution information of a certain thickness portion of the subject is obtained.
As means for obtaining blood flow distribution information, other than the above-mentioned Doppler method, a method for obtaining a moving speed by correlation of echo waveforms, a method for measuring fluctuations in the envelope of echoes, and a granularity generated in blood flow There is also a method using an echo trace.

Next, it is determined whether or not blood vessels are present in each slice of the collected blood flow distribution images of a plurality of slices. Then, in the slice in which the existence of the blood vessel is recognized, only the blood vessel wall is extracted by the edge extraction technique. Further, it is judged which blood vessel wall of each extracted slice is connected to the blood vessel wall of an adjacent slice (belongs to the same blood vessel), and three-dimensionally displays the blood vessel wall as a surface. Thereby, the blood vessel traveling can be recognized three-dimensionally.

However, the conventional device has the following drawbacks. (1) When two blood vessels are overlapped or the blood flow velocity detection sensitivity is insufficient and the blood vessel wall cannot be extracted in the middle slice, the position of the blood vessel wall, the number of blood vessels, and the connection are erroneously determined. Sometimes, the judgment was complicated and it took time.

(2) There is a lot of uncertainty in the connection information of the blood vessels in the three-dimensional display, the blood vessel walls are not connected and displayed only by the automatic processing, and it is necessary to provide the connection information through the dialogue with the operator. There was also a heavy burden on the operator. further,
In an ultrasonic diagnostic apparatus that obtains a blood flow distribution image by the Doppler method, it is necessary to transmit and receive a pulse for a certain period of time on one scanning line to capture the phase change due to the Doppler effect. When the blood flow velocity changes accordingly, there is a problem that the blood flow is not detected and the blood vessel is interrupted at the place where the scanning is performed at the time phase when the velocity decreases such as diastole.

(3) In order to detect the phase change of the reflected ultrasonic echo based on the Doppler effect, it is necessary to transmit and receive the ultrasonic pulse for each raster for a certain time. However, there is a drawback that the three-dimensional scanning of 3 requires a very long time.

(4) Since slices or regions having different scan times are combined and displayed as one three-dimensional image, when the subject moves due to respiration or pulsation, the blood vessels are blurred and displayed thicker. In some cases, they were connected discontinuously.

(5) Due to the restriction of the collection time of three-dimensional data and the restriction of the storage capacity, the scanning line density becomes coarse between the slices and within the slices, the amount of information for automatic recognition is small, and the automatic recognition rate is low. There are problems such as deterioration and the quality of the reconstructed three-dimensional image. Further, when storing an image, it is conceivable to store a three-dimensional image of a combined blood vessel wall or a two-dimensional blood flow distribution image of all slices before combination. There is also a problem that the three-dimensional image viewed cannot be reconstructed and the storage capacity becomes huge when the two-dimensional blood flow distribution image of all slices is stored.

As described above, in the conventional ultrasonic diagnostic apparatus, when performing three-dimensional display of a blood vessel or the like, surface display is performed by recognizing a blood vessel wall of a plurality of blood vessels running or a vessel running in a complicated manner. When performing 3D display of a blood vessel wall by interpolating between different slices, the blood vessel running is erroneously recognized, and it may not be recognized correctly or the automatic recognition may not be performed automatically. There were problems such as the inability to do so, and the intervention of the operator was necessary.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to address the above-mentioned circumstances, and an object thereof is to detect a slice in the middle because two blood vessels overlap each other or the blood flow velocity detection sensitivity is insufficient. To provide an ultrasonic diagnostic apparatus capable of correctly determining the position of the blood vessel wall, the number of blood vessels, and the connection between the blood vessel walls in a short time even when the blood vessel wall cannot be extracted, and performing three-dimensional display of the blood vessel wall. Is.

Another object of the present invention is to provide an ultrasonic diagnostic apparatus capable of three-dimensionally displaying a blood vessel wall by automatically extracting the blood vessel wall from the blood flow distribution image without the operator interactively giving connection information. It is to be.

Another object of the present invention is to be able to detect blood flow even in a time phase in which the velocity decreases, such as diastole, when the blood velocity changes according to the heartbeat of an artery or the like, and a three-dimensional display is possible. It is an object of the present invention to provide an ultrasonic diagnostic apparatus in which the blood vessel is not interrupted during the case.

Still another object of the present invention is to perform a three-dimensional scan of a subject within a short time, extract a blood vessel wall from a blood flow distribution image of a plurality of slices, and perform a three-dimensional display of the blood vessel wall. It is to provide a possible ultrasonic diagnostic method.

Still another object of the present invention is that when the blood vessel walls extracted from slices at different scan times are combined and displayed as one three-dimensional image, the subject moves due to breathing or pulsation during scanning. Another object of the present invention is to provide an ultrasonic diagnostic apparatus in which blood vessels do not appear blurred and thick and are not connected discontinuously.

Still another object of the present invention is to combine blood vessel walls extracted from blood flow distribution images of a plurality of slices and display them as one three-dimensional image, and store the blood flow distribution images of all slices in a small capacity. An object of the present invention is to provide an ultrasonic diagnostic apparatus that can efficiently store in a medium.

[0017]

The present invention takes the following means in order to solve the above problems and achieve the object. The ultrasonic diagnostic apparatus according to claim 1, wherein means for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, means for extracting a blood vessel wall from each of the blood flow distribution images of the plurality of slices, Means for displaying the three-dimensional display of the blood vessel wall by synthesizing the extracted blood vessel wall. The extraction means extracts the blood vessel wall according to the degree of spread of the flow velocity distribution for a thick blood vessel without turbulence. It is characterized in that the edges of the blood flow distribution image are extracted as blood vessel walls for thin blood vessels without flow and blood vessels with turbulent flow.

In the ultrasonic diagnostic apparatus of the second aspect, the extraction means is a fast flow having a narrow velocity distribution in the central portion,
The peripheral portion is characterized in that the blood vessel wall is determined based on the fact that the velocity is wide and the flow is slow.

An ultrasonic diagnostic apparatus according to a third aspect of the present invention is a means for obtaining blood flow distribution images of a plurality of slices of a subject using ultrasonic waves, and a blood vessel wall is extracted from each of the blood flow distribution images of the plurality of slices. And a synthesizing unit for synthesizing the extracted vascular wall to display the vascular wall three-dimensionally, the synthesizing unit including a blood vessel diameter, a blood flow velocity, a blood flow rate, a blood flow direction, and a velocity change in the blood vessel. It is characterized in that whether or not the blood vessel wall belongs to the same blood vessel is determined according to at least one of the pattern and the velocity distribution in the blood vessel.

An ultrasonic diagnostic apparatus according to claim 4 is a means for obtaining blood flow distribution images of a plurality of slices of a subject using ultrasonic waves, and a blood vessel wall is extracted from each of the blood flow distribution images of the plurality of slices. And a synthesizing means for synthesizing the extracted blood vessel walls and performing three-dimensional display, the synthesizing means including a blood vessel diameter, a blood flow velocity, a blood flow rate, a blood flow direction, a velocity change pattern in the blood vessel, and a blood vessel. It is characterized in that it is determined whether or not the blood vessel branches or intersects according to at least one of the velocity distributions in the inside.

An ultrasonic diagnostic apparatus according to a fifth aspect obtains a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizes blood flow distribution images of the plurality of slices, and displays a blood vessel wall three-dimensionally. The ultrasonic diagnostic apparatus is characterized by obtaining a blood flow distribution image of an artery by performing a slow motion scan synchronized with a heartbeat so as to obtain velocity information of all time phases.

In the ultrasonic diagnostic method according to the sixth aspect, blood flow distribution images of a plurality of slices of the subject are obtained using ultrasonic waves, and the blood flow distribution images of the plurality of slices are combined to display the blood vessel wall three-dimensionally. In the ultrasonic diagnostic method, first, the slice interval and the scanning line density are roughly set so that the outline of the blood vessel can be grasped, the subject is scanned to obtain a blood flow image, and then the slice interval and the scanning line density are finely set. The feature is that only the vicinity of the blood vessel is set and scanned.

An ultrasonic diagnostic apparatus according to a seventh aspect obtains a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizes the blood flow distribution images of the plurality of slices, and displays a blood vessel wall three-dimensionally. When an ultrasonic diagnostic apparatus detects a motion of a subject based on a three-dimensional movement vector based on a three-dimensional correlation of reflected waves and synthesizes blood flow distribution images of a plurality of slices based on the detected motion of the subject It is characterized in that the movement of the subject is corrected.

An ultrasonic diagnostic apparatus according to claim 8 obtains a blood flow distribution image of a plurality of slices of a subject by using ultrasonic waves, synthesizes the blood flow distribution images of the plurality of slices, and displays a blood vessel wall three-dimensionally. In the ultrasonic diagnostic apparatus, the blood flow distribution images of two slices are simultaneously obtained while shifting the slice position, and the distortion of the blood flow distribution image of the new slice is temporally used by using the distortion of the image of the old slice as a reference value. The feature is that correction is performed.

The ultrasonic diagnostic apparatus according to claim 9 transmits and receives ultrasonic waves using an ultrasonic probe brought into contact with the body surface of the subject, and obtains blood flow distribution images of a plurality of slices of the subject,
In an ultrasonic diagnostic apparatus that synthesizes blood flow distribution images of multiple slices and displays a blood vessel wall three-dimensionally, when a motion of an ultrasonic probe is detected, a portion newly entered into the transmitting / receiving surface is connected to the transmitting / receiving surface so far. It is characterized in that the field of view is widened, the last information is held in the part outside the transmitting / receiving surface, and the image distortion is corrected in the part where both old and new information can be obtained.

The ultrasonic diagnostic apparatus according to claim 10 obtains a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves,
In an ultrasonic diagnostic apparatus that synthesizes blood flow distribution images of a plurality of slices and three-dimensionally displays a blood vessel wall, a low-speed respiratory fluctuation component that is not synchronized with a heartbeat in the blood flow distribution image and a fast heartbeat fluctuation that is synchronized with the heartbeat It is characterized by comprising means for detecting a component, and means for performing motion compensation by a low-pass filter process in the time axis direction for a respiratory fluctuation component and by averaging processing for each cardiac time phase for a heartbeat fluctuation.

The ultrasonic diagnostic apparatus according to claim 11 obtains a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves,
In an ultrasonic diagnostic apparatus that synthesizes blood flow distribution images of a plurality of slices and three-dimensionally displays a blood vessel wall, when storing the blood flow distribution image of each slice, only the region where the blood vessel exists in each slice image is stored. However, the storage capacity is saved by not storing the region where no blood vessel exists.

[0028]

[Action] By taking such means, the following action is exhibited. According to the ultrasonic diagnostic apparatus of claims 1 to 4, even if two blood vessels are overlapped or the blood vessel velocity cannot be extracted in a slice in the middle because of insufficient detection sensitivity of the blood flow velocity, The position of the blood vessel wall, the number of blood vessels, and the connection can be correctly determined in a short time, and the three-dimensional display of the blood vessel wall can be performed. Further, the operator can automatically extract the blood vessel wall from the blood flow distribution image without interactively giving the connection information, and can display the blood vessel wall three-dimensionally.

According to the ultrasonic diagnostic apparatus of the fifth aspect, when the blood flow velocity changes according to the heartbeat of an artery or the like, the blood flow can be detected even in the time phase when the velocity decreases such as diastole. It is possible to prevent the blood vessels from being interrupted during the three-dimensional display.

According to the ultrasonic diagnostic method of the sixth aspect, the three-dimensional scanning of the subject is performed within a short time, the blood vessel wall is extracted from the blood flow distribution image of a plurality of slices, and the three-dimensional blood vessel wall is extracted. Display can be performed.

According to the ultrasonic diagnostic apparatus of any one of claims 7 to 10, when the blood vessel walls extracted from the slices at different scan times are combined and displayed as one three-dimensional image, breathing is performed during the scan. Even if the subject moves due to pulsation or pulsation, the blood vessels will not be blurred and displayed thickly, or will not be connected discontinuously.

According to the ultrasonic diagnostic apparatus of claim 11, the blood vessel walls extracted from the blood flow distribution images of a plurality of slices are combined and displayed as one three-dimensional image, and the blood flow distribution images of all the slices are displayed. Can be efficiently stored in a small-capacity storage medium.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ultrasonic diagnostic apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the entire first embodiment. The ultrasonic probe 10 is generally a sector-type electronic scanning ultrasonic probe,
It consists of many (linear array) ultrasonic transducers arranged in one dimension. By changing the timing of the voltage applied to each transducer, the ultrasonic beam can be electronically scanned in a fan shape or focused. The probe 10 is not limited to the sector type electronic scanning type, and may be a linear scanning type or a mechanical scanning type. Further, as will be described later, in the present embodiment, the probe is manually moved or sequentially shifted along the surface of the subject by an actuator (not shown) to scan a plurality of slices. An ultrasonic probe including a large number of (matrix array) ultrasonic transducers may be used.

The ultrasonic probe 10 is connected to the transmitting / receiving circuit 12. In the transmission / reception circuit 12, as shown in FIG. 2, the output of the oscillator 30 that determines the frequency for vibrating the ultrasonic transducer is supplied to the probe 10 via the delay circuit 32 and the pulse generator 34. The pulse generator 34 supplies a drive pulse to the probe 10 at a constant cycle. The reciprocal of this cycle is the repetition frequency (rate frequency) of the ultrasonic beam. The delay circuit 32 is composed of a large number of delay lines each having a different delay time, and the output of each delay line is supplied to each of a large number of vibrators. By changing the delay time, the direction (raster direction) of the ultrasonic beam emitted from the probe 10 can be changed. The delay time is controlled by the scan controller 70 described later.

The reflected wave signal received by the probe 10 is supplied to the adder 38 via the preamplifier 36 and the delay circuit 32. Here again, the output of each transducer is supplied to the adder 38 via the respective delay lines with the same delay time as at the time of transmission. The output of the adder 38 is input to the amplitude detector 14, and the intensity of the reflected wave of the ultrasonic beam in each raster direction is detected. The output of the amplitude detector 14 is input to a digital scan converter (DSC) 18 as brightness information of each raster, that is, B mode image (tomographic image) information. The raster of the ultrasonic probe 10 is fan-shaped, and the raster of the display unit 28 is horizontal as in the normal television system. Therefore, the DSC 18 changes the raster direction (scan direction) of the input image and outputs it. It is a thing.

The output of the adder 38 and the output of the oscillator 30 in the transmission / reception circuit 12 are supplied to the Doppler shift detector 16a. The Doppler shift detector 16a is a circuit for detecting the Doppler shift frequency by the quadrature detection method, and the mixer 40a,
40b, 90 ° phase shifter 42, low-pass filter (LP
F) 44a and 44b. The output of the adder 38 is output from the oscillator 30 by the mixers 40a and 40b, and the 90 ° phase shifter 4
It is multiplied with the output of 2. Therefore, the mixer 40a,
A Doppler shift frequency and a high frequency component (twice the transmission frequency + Doppler shift frequency) are obtained from 40b. LPF4
Reference numerals 4a and 44b remove high-frequency components from the outputs of the mixers 40a and 40b, and their outputs are the cosine and sine components of the Doppler shift frequency, respectively. The Doppler shift frequency has two channels, the cosine and the sine, so that the polarity of the shift frequency can be detected.

The output of the Doppler shift detector 16a is supplied to an MTI (Moving Target Indicator) calculator 16b for color Doppler. A detailed block diagram of the MTI calculator 16b is shown in FIG. The outputs of the LPFs 44a and 44b are input to the autocorrelator 54 via the A / D converters 50a and 50b and the MTI filters 52a and 52b, respectively.
The output of the autocorrelator 54 is an average speed calculation circuit 56, a dispersion calculation circuit (speed distribution calculation circuit) 58, and a power calculation circuit 60.
The average velocity (or maximum velocity), the velocity distribution (or velocity distribution width), and the scattered power information from the blood flow, which are supplied to the arithmetic circuits 56, 58, and 60, are supplied to the DSC1.
8 are supplied. The MTI filters 52a and 52b are for removing unnecessary reflected waves (clutter components) from fixed reflectors (blood vessel wall, heart wall, etc.), and are high pass characteristic digital filters. Alternatively, the MTI filter may be configured in an analog manner with a delay line for subtracting a reflection signal after a fixed time from each reflection signal to remove a clutter component and a subtracter. Average speed calculation circuit 5
6, the output of the distributed arithmetic circuit 58 and the power arithmetic circuit 60 is D
Supplied to SC18.

The two-dimensional blood flow image information output from the DSC 18 is supplied to the memory 20 and the blood vessel wall extraction circuit 24. A motion compensation circuit 22 is also connected to the memory 20. The blood vessel wall extraction circuit 24 uses 2 for each slice.
The blood vessel portion is detected from the three-dimensional blood flow distribution image, and the edge thereof is extracted. The blood vessel wall extraction circuit 24 includes a scan controller 70.
Are connected. The scan controller 70 controls the transmission / reception circuit 12 according to the extracted region of the blood vessel wall to control the scanning range and scanning density. The blood vessel wall information of each slice is supplied to the blood vessel wall connection circuit 26, blood vessel walls belonging to the same blood vessel are connected, and a three-dimensional image of the blood vessel wall is created.
It is displayed on the display unit 28. An image storage unit 29 such as a magneto-optical disk device is also connected to the blood vessel wall connection circuit 26. An electrocardiograph 72 is also connected to the scan controller 70 for heartbeat synchronization.

Next, the operation of this embodiment will be described. First,
The scan controller 70 aligns the scanning plane of the ultrasonic probe 10 with a predetermined slice of the subject, and the scan controller 70 applies ultrasonic pulses to each raster for a certain time as in the case of displaying a normal two-dimensional blood flow distribution image. Send and receive waves. Amplitude detector 1
4, the amplitude of the reflected ultrasonic echo is detected, and the blood flow information detector 16 detects the phase change of the reflected ultrasonic echo based on the Doppler effect to obtain the blood flow information at each depth position on the scanning line. By scanning this raster within a slice, a two-dimensional blood flow distribution image is obtained within the DSC 18. Then, a blood flow distribution image is similarly obtained while slightly shifting the slice position, a blood flow distribution image for a plurality of slices is created, and blood flow distribution information of a certain thickness portion of the subject is obtained. The blood vessel wall extraction circuit 24 extracts the blood vessel wall from the blood flow distribution image of each slice, and the blood vessel wall connection circuit 26 connects the blood vessel walls of adjacent slices to obtain three-dimensional image information of the blood vessel wall.
The blood vessel wall image is displayed on the display unit 28 as a three-dimensional image. The cardiac phase is used as display timing information when displaying a blood vessel wall.

Although it is necessary to perform high-density scanning in order to obtain the blood flow distribution, it is not necessary to perform three-dimensional scanning of the entire region with the same accuracy, and it is sufficient to densely perform only the blood vessel portion. This allows for high resolution, even when
An image with desired accuracy can be obtained without increasing the storage capacity of the two-dimensional blood flow distribution image or the time required to create the three-dimensional image of the blood vessel wall. Therefore, first, as shown in FIG. 4, the whole is roughly scanned with a coarse scanning line density (the slice interval is increased and the ultrasonic beam width is increased).
In FIG. 4, a plane orthogonal to the slice is also indicated by a broken line for convenience of description.

By this rough scanning, a blood flow distribution image with a small amount of information can be collected at high speed. From this information, the blood vessel wall extraction circuit 24 distinguishes the place where blood vessels exist and the place where blood vessels do not exist in the slice.

When this distinction is completed, the scan controller 70 reduces the scan volume, and as shown in FIG. 5, only the region where the blood vessel exists or the edge of the blood vessel has a dense scan line density (narrow the slice interval, Make the ultrasonic beam narrower and scan with. FIG. 5 is a plan view of FIG. 4 seen from above and having the same depth. As a result, a high-resolution blood flow distribution image can be collected at high speed, and the scan time can be shortened. Also, since the scan time can be shortened, the time difference between the beginning and the end of the scan will be small, and even if there is a change in the flow velocity of the artery etc., the blood flow distribution can be detected for all time phases, and the dead part will be eliminated. It is possible to prevent the three-dimensional display of the wall from becoming discontinuous.

If data is collected by applying the aperture synthesis method, the collection time can be further shortened. Since the collection time is short in this way, it is easy to redo the scan, and as shown in FIG. 6, the determination accuracy is determined for the portion 66 where the blood vessel wall connection circuit 24 cannot determine the blood vessel connection status (branch or intersection). The location can be scanned again to improve. It is preferable that the scanning density of the second scanning is finer than that of the first scanning.

When diagnosing a subject that moves rapidly, the scan controller 70 performs motion compensation by the following control. If the blood vessel is running as shown in FIG. 7,
As shown in FIG. 8, data of two adjacent slice planes are simultaneously acquired (T0, T1, T2, T3 ... Denote data acquisition timing), and the slice position is set to 1 for each data acquisition.
Only the slices are shifted, and the data of each slice # 1, # 2, # 3 ... Are collected twice in total. This makes it possible to increase the amount of information for compensating for the movement of the subject based on the time difference. That is, two slices, old and new, are acquired at the same time, and the image of the old slice acquired earlier in time is used as a reference value to perform motion correction on the new slice acquired later in time, and then the blood vessel wall is connected. As a result, even when the subject moves due to respiration or pulsation, blood vessels are displayed thick and it is possible to prevent some blood vessels from being discontinuously connected.

The DSC 18 stores a two-dimensional blood flow distribution image consisting of echo amplitude information of the subject tissue and blood flow velocity information in the image memory 20 of multi-section / multi-time phase. On this memory, the blood flow distribution information is not yet three-dimensionally connected,
It is in the state of collection of blood flow information at points on some lines obtained by ultrasonic beam scanning. The DSC 18 obtains blood flow information between the scanning lines by interpolation. Memory 20
Has a capacity to store not only data for one three-dimensional scan but also data for a long time corresponding to several heartbeat periods.

The motion compensation circuit 22 connected to the memory 20 has a function of correcting the image distortion in the memory 20 due to the influence of the motion of the subject being different due to the scanning time difference (scanning time difference between slices), and the memory. It has a function of rearranging a large number of images in 20 into images of the same time phase. With these functions, the spatial or temporal distortion of the image can be removed. Therefore, the structure of the data / address in the memory 20 is not an address map in a spatial / temporal order, but the spatial position (coordinate) / time (temporal phase) of each data is data as shown in FIG. It is given as the label of and the temporal rearrangement and the spatial distortion correction are realized by changing this label.

Since the data is labeled in this way, the memory capacity can be reduced,
A large amount of data can be efficiently stored even if data is collected by two scans, a rough scan of the entire subject and a dense scan only near the blood vessel.

Next, the image distortion correction operation of the motion compensation circuit 22 will be described. Image distortion includes spatial distortion and temporal distortion. First, the spatial image distortion correction function will be described. As means for detecting the motion of the subject, a three-dimensional displacement detection correlator that is suitable for detecting relatively fast motion and that detects changes in three-dimensional position of tissue echo information, and a diagram suitable for extremely fast motion There is a two-dimensional correlator such as 8 that captures changes in the data collected with a relatively short time difference. From these, the movement of the subject at each location is obtained. Since the main cause of image distortion is respiration or pulsation, the spatial resolution of motion detection need not be so good.

When motion is detected, it is determined if this motion is merely a probe movement to change slice position. This can be determined based on the motion detector and the direction of motion. That is, if there is a movement along the body surface near the body surface contact surface, it can be determined that the movement of the probe.

When it is determined that the movement of the probe has occurred, as shown in FIG.
(Collected at time T2) uses the obtained data itself,
The part OLD out of the field of view (collected at time T1) retains (freezes) the previous data for a certain period of time or until the operator deletes it, and the part in the field of view before and after the movement is locally affected by respiration. After the movement is corrected, the pre-movement data and the post-movement data are added and combined (compound processing).

For the portion not determined to be the movement of the probe, the position is corrected by the pulsation as shown in FIG. 9 to virtually reproduce the position at the same time. Further, as shown in FIGS. 11 and 12, corrections due to camera shake and pulsation are performed.

Next, as correction of temporal distortion, FIG.
The cardiac phase is divided appropriately as shown in (for example, T1 to T6
6), and the blood flow information is processed for each time phase using a fluctuation removing means such as an average to remove respiratory fluctuations. And
The slices are rearranged for each temporary phase. In particular, when scanning the arterial system, the start time of scanning is slightly shifted with respect to the pulsation timing of the patient such as an electrocardiogram so that the scanning time phase at the same site is always the same as that of diastole. It is preferable not to be late and difficult to detect.

The blood vessel wall extraction circuit 24 extracts the blood vessel wall based on the blood flow information from which the spatial / temporal distortion has been removed in this way, and the adjacent slices are spatially close to each other, or the velocity, direction, The three-dimensional shape of the blood vessel is recognized by estimating the extent of the thick blood vessel from the similarity of the velocity distribution and the like.

In the conventional ultrasonic three-dimensional blood vessel display device, in order to display the blood vessel wall as a surface, the boundary of the blood vessel is extracted from the display of the ultrasonic blood flow imaging device as the edge of the blood vessel display. However, if two blood vessels overlap or if there is a lack of sensitivity and there is a dropout, the position and number of blood vessel edges,
Sometimes the connection was misjudged. Moreover, since the judgment is complicated, it takes time to judge.

On the other hand, the blood vessel wall extraction circuit 2 of this embodiment
In the case of imaging a thick blood vessel without turbulence, the feature 4 is that the central flow is a fast flow with a narrow velocity distribution (BW) and the peripheral flow is a slow flow with a wide velocity distribution, as shown in FIG. Then, the peripheral flow is detected, and thereby the blood vessel wall is extracted.

When imaging a thin blood vessel without turbulence, the resolution cell (pixel) is 1 as shown in FIG.
Since there is only one, the center and the periphery cannot be distinguished from the velocity distribution, so the edge of the pixel is detected as the blood vessel wall.

When imaging blood vessels with turbulence,
The edges of the blood flow imaging display are extracted as is conventional. Accordingly, when displaying the blood vessel traveling as a perspective image, the display color near the center of the thick blood vessel can be made a bright color to give a stereoscopic effect, and the thick blood vessel can be easily recognized.

Further, in the conventional ultrasonic three-dimensional blood vessel display device, the blood vessels are not connected and displayed, and there is a lot of uncertainty in the blood vessel connection information in the three-dimensional display, and the connection information is given by the dialogue with the operator. Needed to be installed. Conventionally, the blood vessel wall connection is basically determined only by whether or not they are in contact with each other, but the blood vessel wall connection circuit 26 of the present embodiment additionally has the following: (1) Blood vessel diameter ( Cross-sectional area: S), flow velocity V,
The direction, the intra-vascular velocity distribution BW, and the temporal change pattern of the flow velocity (PI: determined by the pulsarity index, etc.) are almost the same, and (2) the original flow rate Q of the original blood vessel and the two after the bifurcation Whether or not there is a bifurcation is also utilized by using the fact that the sum of the blood flow rates is the same, and (3) the characteristics of the central flow and the features of the peripheral flow are concentrically distributed in the blood vessel cross section in a thick blood vessel other than the bifurcation. . For example, in the case of FIG. 6 shown above,
The following two decisions are included.

[0059]

[Equation 1] The bifurcation pattern is between blood vessel A and blood vessels B and C (non-concentric velocity distribution), that is, blood vessel A branches into blood vessel B and blood vessel C.

[0060]

[Equation 2]

The blood vessel D and the blood vessel E are connected and there is no branch of a large blood vessel (there may be a branch of a fine blood vessel). Further, as shown in FIG. 16, the direction of connection is determined by paying attention to the position of the central flow, not the closest position.

In order to image blood flow in the arterial system, it is preferable to perform slow motion scanning synchronized with heartbeat to avoid a period in which blood flow cannot be detected during diastolic velocity reduction.

By adopting these techniques, it is possible to reduce the probability of mistakenly connecting different blood vessels to display three-dimensionally, and the operator can display the blood vessels in a connected state without inputting connection information. Can be easily grasped. Also,
If there is an error in the automatic recognition of the device, the operator may need to confirm the connection again. In this case, the next closest candidate is displayed as the connection target, and the operator is asked to make a decision.
If it is still incorrect, only the target part is rescanned and connection display is performed. Note that the operator may specify the connection target by dialogue during this process. When the velocity of the artery or the like in the diastole is low and cannot be recognized, the blood vessel wall connection circuit 26 interpolates from the information of the preceding and following time phases, so that the three-dimensional display image for each cardiac time phase reproduces the heartbeat cycle and the like. It is displayed at the timing.

The memory 20 may be connected to the DSC 18 via a digital data interface so that multi-section / multi-time phase data can be stored as digital data.

[0065]

According to the ultrasonic diagnostic apparatus of the present invention,
The following effects can be obtained. The determination of whether or not they are the same blood vessel between adjacent slices or in a tomographic image, and the discrimination of bifurcations and intersections are performed not only by the proximity of the blood vessel center but also by their blood vessel diameter, flow velocity, direction proximity, blood vessel The similarity of the internal velocity change pattern, the closeness of the intravascular velocity distribution, etc. are also comprehensively used for recognition. Also, regarding the extraction of the blood vessel wall, in order to ensure reliability, detection of the arterial system is performed by slow motion scanning synchronized with heartbeat so that velocity information of all time phases can be obtained at all locations,
Information about the period when blood flow cannot be detected during diastolic velocity is not determined to be a blood vessel even without blood flow information, and in the case of a thick blood vessel without turbulence, the central flow is a fast flow with a narrow velocity distribution. , The surrounding area is judged to be a blood vessel wall using the characteristic of slow flow with a wide velocity distribution, and for thin blood vessels without turbulence or blood vessels with turbulence,
Let the edge of a pixel be a blood vessel wall. This reduces the probability of accidentally connecting different blood vessels for three-dimensional display,
Blood vessels are correctly connected and displayed even if the operator does not input connection information.

A three-dimensional movement vector based on the three-dimensional correlation of the tissue echo is calculated, and this is integrated. The old and new slices are collected at the same time, the image distortion of the old slice is used as a reference value, and the new slice is corrected and combined. If the body surface is also moving, it is judged that the probe is moving and not the distortion correction but the part newly entered in the scan area and the previous scan area are connected and combined to display a wide field of view. . The last information is retained where the information deviates from the scan area due to movement, and image distortion is corrected and image quality is improved by compounding in the area where both old and new information can be obtained. Regarding the detection and correction of image distortion, in consideration of the difference in heartbeat time phase, respiratory fluctuation (slow one that is not synchronized with heartbeat) is subjected to LPF processing in the time direction at various places and synchronized with heartbeat fluctuation heartbeat. ) Performs average processing for each cardiac phase at each location. By providing a means for detecting the movement of these objects, and correcting the position when synthesizing the three-dimensional images, even if there is movement of the object, position information can be stored when synthesizing as a three-dimensional image. It is possible to correct the blurring and discontinuity of an image, reduce the patient's burden such as breath holding at the time of examination, and provide a high-quality three-dimensional image. This is important for making the display color near the center of the thick blood vessel a bright color to give a three-dimensional effect when the running state of the blood vessel is three-dimensionally displayed as a perspective image, and to facilitate the recognition of the thick blood vessel.

Further, when the blood flow distribution image of each slice is stored, only the portion with blood vessels is stored, and the portion without blood vessels is not stored, so that the storage capacity can be saved.

Further, the scanning time can be shortened by obtaining a blood flow distribution image with a slice interval and scanning line density set roughly so that an outline of the blood vessel can be grasped and then finely scanning only the vicinity of the blood vessel. it can.

[Brief description of drawings]

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

FIG. 2 is a detailed block diagram of the transmission / reception circuit and the Doppler shift detector of FIG.

FIG. 3 is a detailed block diagram of an MTI calculation unit in FIG.

FIG. 4 is a diagram for explaining a rough scan.

FIG. 5 is a diagram for explaining a fine scan.

FIG. 6 is a diagram for explaining a connection state of blood vessels.

FIG. 7 is a diagram showing an example of a running state of blood vessels.

8 is a diagram showing motion compensation in the blood vessel shown in FIG. 7. FIG.

FIG. 9 is a diagram showing a method of storing blood flow information in a memory and a method of correcting distortion.

FIG. 10 is a diagram showing distortion correction and image combination when the probe is moved.

FIG. 11 is a diagram showing a method of correcting image distortion due to camera shake.

FIG. 12 is a diagram showing a method of correcting image distortion due to pulsation.

FIG. 13 is a diagram showing a method of correcting spatial / temporal distortion.

FIG. 14 is a diagram showing a blood vessel wall extraction principle in the case of a thick blood vessel without turbulence.

FIG. 15 is a diagram showing the principle of blood vessel wall extraction in the case of a thin blood vessel without turbulence.

FIG. 16 is a diagram showing a method of determining a connection direction by paying attention to the position of the central flow.

[Explanation of symbols]

10 ... Ultrasonic probe, 12 ... Transceiver circuit, 14 ... Amplitude detector, 16 ... Blood flow information detector, 18 ... DSC, 20 ...
Memory, 22 ... Motion compensation circuit, 24 ... Blood vessel wall extraction circuit,
26 ... Blood vessel wall connection circuit, 28 ... Display unit, 29 ... Storage unit,
70 ... Scan controller, 72 ... Electrocardiograph.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shin Hirama 1385-1 Shimoishigami, Otawara-shi, Tochigi Stock company Toshiba Nasu factory (72) Inventor Yasuhiko Abe 1385-1 Shimoishi, Otawara-shi, Tochigi Company Toshiba Nasu Factory

Claims (11)

[Claims] 1. A means for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, a means for extracting a blood vessel wall from each of the blood flow distribution images of the plurality of slices, and the extracted blood vessel wall And a means for performing three-dimensional display of the blood vessel wall, wherein the extracting means extracts the blood vessel wall according to the extent of the flow velocity distribution for a thick blood vessel having no turbulent flow, and a thin blood vessel having no turbulent flow. An ultrasonic diagnostic apparatus characterized by extracting the edge of a blood flow distribution image as a blood vessel wall for a blood vessel having turbulent flow. 2. The extracting means determines the blood vessel wall based on the fact that the central portion is a fast flow with a narrow velocity distribution and the peripheral portion is a slow flow with a wide velocity distribution. Ultrasonic diagnostic equipment. 3. A means for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, a means for extracting a blood vessel wall from each of the blood flow distribution images of the plurality of slices, and the extracted blood vessel wall And a synthesizing means for performing three-dimensional display of the blood vessel wall, wherein the synthesizing means includes at least the blood vessel diameter, the blood flow velocity, the blood flow rate, the blood flow direction, the velocity change pattern in the blood vessel, and the velocity distribution in the blood vessel. An ultrasonic diagnostic apparatus characterized by determining whether or not the blood vessel walls belong to the same blood vessel according to one. 4. A means for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, a means for extracting a blood vessel wall from each of the blood flow distribution images of the plurality of slices, and the extracted blood vessel wall And synthesizing means for performing three-dimensional display by synthesizing the blood vessel, the blood flow velocity, the blood flow rate, the blood flow direction, the velocity change pattern in the blood vessel, and the velocity distribution in the blood vessel. An ultrasonic diagnostic apparatus according to which it is determined whether or not a blood vessel branches or intersects. 5. An ultrasonic diagnostic apparatus for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizing the blood flow distribution images of the plurality of slices and displaying a blood vessel wall three-dimensionally. An ultrasonic diagnostic apparatus characterized in that a slow motion scan synchronized with a heartbeat is performed to obtain a blood flow distribution image of an artery so as to obtain velocity information of. 6. An ultrasonic diagnostic method for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizing blood flow distribution images of the plurality of slices, and displaying a blood vessel wall three-dimensionally. The interval and scan line density are roughly set to the extent that the outline of the blood vessel can be grasped, and the subject is scanned to obtain a blood flow image. Then, the slice interval and scan line density are finely set, and only the vicinity of the blood vessel is scanned. An ultrasonic diagnostic method characterized by the above. 7. An ultrasonic diagnostic apparatus for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizing the blood flow distribution images of the plurality of slices and displaying a blood vessel wall three-dimensionally, Detecting the motion of a subject based on a three-dimensional movement vector by three-dimensional correlation and correcting the motion of the subject when synthesizing blood flow distribution images of a plurality of slices based on the detected motion of the subject An ultrasonic diagnostic apparatus characterized by: 8. An ultrasonic diagnostic apparatus for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizing the blood flow distribution images of the plurality of slices, and displaying a blood vessel wall three-dimensionally. A blood flow distribution image of two slices is simultaneously obtained while shifting, and the distortion of the blood flow distribution image of a new slice is temporally corrected by using the distortion of the image of an old slice as a reference value. Sound wave diagnostic equipment. 9. An ultrasonic probe that is brought into contact with a body surface of a subject is used to transmit and receive ultrasonic waves to obtain blood flow distribution images of a plurality of slices of the subject and synthesize blood flow distribution images of the plurality of slices. In an ultrasonic diagnostic device that three-dimensionally displays a blood vessel wall, when the movement of the ultrasonic probe is detected, the part newly entering the transmitting / receiving surface is connected to the existing transmitting / receiving surface to widen the field of view and deviates from the transmitting / receiving surface. The ultrasonic diagnostic apparatus is characterized in that the part holds the last information, and the image distortion is corrected in the part where both old and new information can be obtained. 10. An ultrasonic diagnostic apparatus for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizing the blood flow distribution images of the plurality of slices, and displaying a blood vessel wall three-dimensionally. The means for detecting low-speed respiratory fluctuation components that are not synchronized with the heartbeat in the image and high-speed heartbeat fluctuation components that are synchronized with the heartbeat, and the low-pass filter processing in the time axis direction for respiratory fluctuation components An ultrasonic diagnostic apparatus comprising: means for performing motion compensation by averaging processing for each cardiac phase. 11. An ultrasonic diagnostic apparatus for obtaining a blood flow distribution image of a plurality of slices of a subject using ultrasonic waves, synthesizing the blood flow distribution images of the plurality of slices, and displaying a blood vessel wall three-dimensionally. When storing the blood flow distribution image, only the region where blood vessels exist in each slice image is stored, and the region where blood vessels do not exist is not stored, thereby saving storage capacity. .