JP2001340340A - Ultrasonic diagnosing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously image a perfusion and a blood vessel blood-stream. SOLUTION: A three-dimensional scanning by an ultrasonic beam is performed to a subject to whom an ultrasonic contrast medium of which the major component is minute air bubbles is applied. Thus, a three-dimensional image for the applicable scanning region is obtained, and the image is displayed on this ultrasonic diagnosing device. In such an ultrasonic diagnosing device, an ultrasonic beam at least for two frames, A and B, which continues while placing a specified stop period of time TB-A by a specified frame rate TA-B which is shorter than the stop period of time, is repeatedly cast, and thus, echo signals are collected from the subject. Then, respectively independent three-dimensional images are formed from the aggregate of the echo signals for the first frame and the aggregate of the echo signals for the second frame. Thus, a three- dimensional image mainly containing information for a perfusion, and a three- dimensional image mainly containing information for a blood vessel bloodstream can be approximately simultaneously obtained respectively.

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 for obtaining a three-dimensional image, and more particularly to an ultrasonic diagnostic apparatus which administers an ultrasonic contrast agent containing microbubbles as a main component to a subject to obtain a blood flow in a blood vessel. The present invention relates to an ultrasonic diagnostic apparatus suitable for observing the state of blood flow and the state of blood flow in organs.

[0002]

2. Description of the Related Art Ultrasound has a wide range of medical applications, and an ultrasonic diagnostic apparatus capable of observing a tomographic image, a blood flow velocity, and the like of a subject is one of typical examples. When an ultrasonic beam is radiated from the ultrasonic transducer into the subject, the ultrasonic beam propagates in the living body, and at the boundary of a biological tissue such as a blood vessel wall or an organ during propagation, that is, at a discontinuous surface of acoustic impedance. Reflection occurs one after another, and returns to the ultrasonic transducer as an echo signal. The amplitude of the echo signal depends on the difference in acoustic impedance at the discontinuous surface. Further, when the ultrasonic beam is reflected on the surface of a moving object such as a blood cell or a heart wall, the echo signal undergoes a frequency shift depending on the velocity component in the beam direction of the moving object due to the Doppler effect. . An ultrasonic diagnostic apparatus is a non-invasive medical diagnostic apparatus capable of obtaining a tomographic image of a soft tissue of a living body and observing a blood flow velocity or the like by processing such an echo signal. And
Compared to other medical modalities such as X-ray diagnostic equipment, X-ray CT equipment, MRI equipment and nuclear medicine equipment, real-time display is possible, the equipment is small and relatively inexpensive, there is no radiation exposure and high safety, blood flow imaging Is possible. For this reason, ultrasound diagnosis is performed in a wide range of areas such as the circulatory organ (heart), abdomen (liver, kidney, etc.), mammary gland, thyroid gland, urology and obstetrics and gynecology. It also has the advantage that the operation is simple and the apparatus can be moved to the bed side to easily perform the inspection.

[0003] In the field of such ultrasonic diagnosis, in recent years, when a heart or abdominal organ is examined, an ultrasonic contrast agent (hereinafter, simply referred to as a contrast agent) is injected from a vein of a subject. Attention has been focused on a contrast echo method for evaluating the state of blood flow. The technique of injecting a contrast agent from a vein
Since the method is less invasive than the technique of injecting a contrast medium from an artery using a catheter, diagnosis using this evaluation method is becoming widespread. Here, the physical characteristics of the contrast agent will be briefly described. As the ultrasonic contrast agent, one containing microbubbles as a main component is used. Microbubbles have a very small acoustic impedance, and the difference in acoustic impedance with the organs, tissues, or blood components in the subject is extremely large, so the intensity of the echo signal from the microbubbles is significantly stronger than that from the tissue boundary, It is suitable as a contrast agent. The higher the injection amount or concentration of the contrast agent, the greater the contrast effect. The contrast agent as a main component the microbubbles, for example Levovist mainly composed of galactose (Levovist ^(R); Schering) is known, if a property to enhance the intensity of the echo signal Alternatively, the main component may be other microbubbles or materials.

[0004] By the way, the microbubbles have a property that they are collapsed and disappear in a short time by ultrasonic irradiation at an ultrasonic irradiation power (sound pressure) of a level used for ordinary diagnosis. That is, it is known that bubbles in water (in blood) exhibit physical behavior of a primary vibration like a spring with respect to sound pressure. At this time, the bubbles depend on the size (diameter of the bubbles). Vibrates at a unique resonance frequency. Then, the bubble oscillates at the maximum amplitude under the resonance frequency and its disappearance is promoted. The microbubbles in the contrast agent have various sizes in the range of about several microns, and the resonance frequency differs for each individual microbubble. However, in practice, most of the microbubbles having a resonance frequency included in the frequency band of the transmission wave disappear instantaneously because the transmission wave has a wide frequency band with a certain width. It is thought to be done. Considering a clinical site, since the contrast agent is supplied to the region of interest (ROI) one after another by the blood flow, most of the microbubbles disappear at that site by one ultrasonic irradiation. However, if new microbubbles exist in the same region of interest at the time of the next ultrasonic irradiation, it is assumed that the contrast effect is maintained. However, in practice, ultrasound transmission / reception is performed several thousand times per second, and in consideration of the presence of blood flow in organ parenchyma or relatively small blood vessels having a low blood flow velocity, contrast is not sufficient on these diagnostic images. The microbubbles disappear one after another before confirming the brightness enhancement by the agent, and the contrast effect is instantaneously reduced.

[0005] Regarding the phenomenon in which microbubbles disappear due to such ultrasonic irradiation, the present inventors have described one research presentation in "Study of 67-95 Flash Echo Imaging (1), Naohisa Kamiyama et al. 7th Annual Meeting of the Japanese Society for Ultrasound Medicine, June 1996, and reported that the imaging method called flash echo imaging can improve the brightness enhancement.
No. 6,086,045. In principle, this imaging method uses an intermittent scan of one frame every few seconds instead of the conventional ultrasonic scan that is continuously performed at a speed of several tens of frames per second. Intermittent periods (that is,
During the ultrasonic irradiation stop time), the microbubbles filled without dividing into the scanning region (that is, the region of interest) are eliminated at a stretch by the next ultrasonic scanning to obtain a high echo signal. Method. With the development of such new imaging methods, expectations and needs for three-dimensional images are increasing in the field of ultrasonic diagnosis as well as in the field of X-ray CT and MRI. The three-dimensional image is three-dimensional, including information on the depth direction in addition to the two-dimensional tomographic image.
This is the reason why it is possible to more clearly observe the shape of the tissue, the running state of the blood vessels, and the like.

In order to form a three-dimensional image, it is necessary to perform three-dimensional ultrasonic scanning on the subject to acquire three-dimensional image data. ing. As one of them, a method has been proposed in which a two-dimensional array ultrasonic probe in which a large number of ultrasonic transducers are two-dimensionally arranged is used to simultaneously capture three-dimensional distribution echo signals. Also, as another method,
There is also known a method of relatively simply capturing an echo signal of a three-dimensional distribution using an ultrasonic probe in which a large number of conventional ultrasonic transducers are arranged one-dimensionally. Specifically, the method using the one-dimensional array ultrasonic probe scans a two-dimensional cross section while gradually moving the one-dimensional array ultrasonic probe to which the position sensor is attached, and scans the two-dimensional cross section. This is a method of simultaneously capturing and recording scanning position information from a position sensor together with an echo signal. Then, after scanning a desired three-dimensional space and collecting data, the recorded data is reconstructed with reference to the position information to form a three-dimensional image and displayed on a display. The method using the one-dimensional array of ultrasonic probes may be performed without using a position sensor. In this case, the echo signal is captured while moving the ultrasonic probe at a predetermined speed and angle on the subject, and the data of each two-dimensional cross section is spatially arranged to form a three-dimensional volume image. It is. Therefore, although accurate data cannot be obtained strictly in the depth direction, it is still possible to provide a sufficient image for grasping the three-dimensional structure of the subject. The construction and display of these three-dimensional images, especially with the recent advances in high-speed data processing equipment,
It can be done in a very short time.

As described above, microbubbles as a contrast agent are easily broken by irradiating an ultrasonic wave. In the observation, blood flow in a blood vessel having a relatively high inflow velocity is well visualized by the effect of a contrast agent, but micro blood flow (hereinafter, referred to as perfusion) in a tissue having a relatively low inflow velocity such as a capillary blood vessel. .)
Is not imaged because microbubbles disappear. However, when performing three-dimensional imaging, as a result, perfusion can be well imaged for the following reasons. In other words, moving the ultrasonic probe in a direction perpendicular to the tomographic plane in order to capture a three-dimensional distribution of echo signals requires a scanning section of the ultrasonic wave,
This is because the microbubbles move one after another into a new area where the microbubbles have not yet disappeared. Note that this method
It is only possible once per administration of the contrast agent or it is necessary to wait again until the contrast agent fills the microvessels of the tissue. The three-dimensional image reconstructed on the basis of such perfusion echo signals is expected to be used for, for example, a diagnosis of the presence or a differential diagnosis of a tumor and exert a great effect. That is, when a spherical space with low brightness exists in the perfusion space in the liver, the site is expected to be an ischemic metastatic liver cancer. Further, by simultaneously measuring the shape, volume, and the like of the site using the measurement function of the ultrasonic diagnostic apparatus, more accurate diagnostic information can be provided.

[0008]

However, a method of forming a three-dimensional image based on a contrast echo method for visualizing the state of blood flow by injecting a contrast agent from a vein of a subject as described above is described. There are various problems to be improved. One is that due to the effect of the disappearance of microbubbles as a contrast agent, the moving speed of the ultrasonic probe is uneven (ie, non-uniformity when moving the ultrasonic probe relatively quickly or slowly). In some cases, the brightness of the imaged perfusion is different.
Second, when imaging perfusion, echo signals of vascular blood flow (hereinafter simply referred to as vascular blood flow) having a higher blood flow velocity than that of capillaries are masked by tissue blood flow, Conversely, it becomes difficult to see. Regarding this problem, the target site (blood vessel) to be observed
Depending on the inflow velocity of the blood flow, the intermittent interval (interval of the stop time) of irradiating the ultrasonic beam, the ultrasonic irradiation power (sound pressure), or the speed at which the ultrasonic probe is moved can be adjusted. By taking countermeasures such as adjustment, it was intended to visualize either vascular blood flow or tissue blood flow, but it could respond to the strong desire to simultaneously image perfusion and vascular system. could not. The present invention has been made to solve the above-described problems, and has been made with the object of providing an ultrasonic diagnostic apparatus capable of forming a three-dimensional image by simultaneously acquiring perfusion and vascular blood flow information. .

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an ultrasonic beam applied to a subject to which an ultrasonic contrast agent containing microbubbles as a main component is administered. By performing three-dimensional scanning, in an ultrasonic diagnostic apparatus that obtains a three-dimensional image of the scanning area and displays the image,
Transmitting and receiving means for repeatedly irradiating an ultrasonic beam for at least two continuous frames to collect echo signals from the subject at a predetermined frame rate shorter than the predetermined stop time after the predetermined stop time; Three-dimensional image processing means for forming independent three-dimensional images from a set of echo signals of a first frame and a set of echo signals of a second frame among frames to be processed. Things. Accordingly, a three-dimensional image mainly including perfusion information and a three-dimensional image mainly including vascular blood flow information can be obtained almost simultaneously.

According to a second aspect of the present invention, an object to which an ultrasonic contrast agent containing microbubbles as a main component is administered is three-dimensionally scanned with an ultrasonic beam, thereby obtaining a tertiary scan of the scan area. In an ultrasonic diagnostic apparatus that obtains an original image and displays the image, while repeatedly irradiating the same scanning line with the ultrasonic beam at least twice, sequentially switching the scanning lines and collecting echo signals for one frame, Transmitting / receiving means for collecting an echo signal from the subject by repeatedly irradiating at least two consecutive ultrasonic beams at a predetermined frame rate shorter than the predetermined stop time after a predetermined stop time; Means for calculating a difference between two echo signals related to the same scanning line collected by the means to obtain a difference signal; A three-dimensional image forming an independent three-dimensional image from a set of difference signals obtained by the difference calculation means of the first frame and a set of difference signals obtained by the difference calculation means of the second frame Image processing means. In this case, the three-dimensional image processing unit includes a processing unit that forms a three-dimensional image independent of a set of one of the echo signals before performing the difference calculation of the first frame. The formed independent three-dimensional images may be superimposed and displayed with their spatial positions aligned. This removes the echo component from the biological tissue and obtains an image reflecting echo data from the contrast agent.Thus, while utilizing the characteristics of the so-called rate subtraction imaging method, a three-dimensional image mainly containing perfusion information is obtained. And a three-dimensional image mainly containing blood vessel blood flow information can be obtained almost simultaneously.

According to a third aspect of the present invention, an object to which an ultrasonic contrast agent containing microbubbles as a main component is administered is three-dimensionally scanned with an ultrasonic beam through an ultrasonic probe. An ultrasonic diagnostic apparatus that obtains a three-dimensional image of the scanning area and displays the image, a position information detecting unit that detects spatial position information of the ultrasonic probe, and the position detected by the position information detecting unit. When the moving distance of the ultrasonic probe exceeds a predetermined threshold value, an ultrasonic signal for at least two consecutive frames is repeatedly irradiated at a predetermined frame rate to collect echo signals from the subject. From the transmitting / receiving means, and a set of echo signals of the first frame and a set of echo signals of the second frame in the continuous frames, form independent three-dimensional images. And a three-dimensional image processing means. This makes it possible to collect echo data at necessary and sufficient intervals and acquire a three-dimensional image mainly containing perfusion information and a three-dimensional image mainly containing vascular blood flow information almost simultaneously. it can. Also, regardless of the moving speed of the ultrasonic probe, it is possible to uniformly obtain the echo luminance by the contrast agent in all tomographic images.

Further, according to the present invention, an ultrasonic probe having a two-dimensionally arranged ultrasonic transducer is applied to a subject to which an ultrasonic contrast agent containing microbubbles as a main component is administered. In an ultrasonic diagnostic apparatus that obtains a three-dimensional image of the scanning area by scanning with an acoustic beam and displays the image, the ultrasonic diagnostic apparatus repeatedly irradiates an ultrasonic beam for at least two frames having different elevation angles at a predetermined frame rate. Transmitting / receiving means for collecting echo signals from the subject, and a set of echo signals of the first frame and a set of echo signals of the second frame having different elevation angles, thereby forming independent three-dimensional images. And a three-dimensional image processing means.
As a result, a three-dimensional image mainly including perfusion information and a three-dimensional image mainly including vascular blood flow information are continuously obtained at a predetermined frame rate without providing an intermittent time (stop time). can do.

In the invention described in each of the above claims,
Acquisition of echo signals for two frames may be performed in synchronization with a desired phase of the electrocardiogram. Also, the first frame and the second frame
May be collected as signals of different video modes, such as B mode and color Doppler mode, for example. Furthermore, the three-dimensional images of the two frames respectively acquired are displayed in parallel with each other in a spatial position, displayed in a superimposed manner, or displayed as a difference image obtained by performing a difference operation for each pixel. In addition, a three-dimensional image formed from a set of echo signals of the first frame can be displayed as an interleaved image cut at a desired cross section. With these display modes, the tissue structure and the blood vessel structure can be grasped more clearly.

According to another aspect of the present invention, a subject to which an ultrasonic contrast agent containing microbubbles as a main component is administered is three-dimensionally scanned with an ultrasonic beam, thereby obtaining a three-dimensional scan of the scan area. In an ultrasonic diagnostic apparatus for acquiring an image and displaying the image, the object is irradiated with an ultrasonic beam for two consecutive frames at a predetermined frame rate shorter than the predetermined stop time after the stop time. The first frame sequentially switches the scan lines while irradiating the same scan line once with the ultrasonic beam, and the second frame scans the same scan line with the ultrasonic beam. Transmitting / receiving means for sequentially switching scanning lines while repeating irradiation at least twice, and a set of echo signals of the first frame are collected as B-mode signals, and a set of echo signals of the second frame are collected. The set of co-signals is collected as a difference signal obtained by performing a difference operation between two echo signals related to the same scanning line, and includes three-dimensional image processing means for forming independent three-dimensional images. The present invention is characterized in that the independent three-dimensional images formed by the three-dimensional image processing means are superimposed and displayed with their spatial positions aligned. As a result, the structure of the vascular blood flow can be very clearly observed in the perfusion image. Also in this case, the background image may be displayed as an interleaved image. In each of the above-mentioned inventions, if a signal containing a large amount of harmonic components with respect to the fundamental component of the echo signal is received as the signal of the first and / or second frame, a signal at a medium position from the body surface is obtained. Thus, a clear image can be obtained, and at least one of the independent three-dimensional images formed by the three-dimensional image processing means is displayed in color, so that the visibility can be further improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ultrasonic diagnostic apparatus according to the present invention will be described below in detail with reference to FIGS. It should be noted that the present invention can be applied to all regions of interest when a contrast medium is administered to a subject and the state of blood flow is observed according to the degree of contrast, but various implementations described below are possible. In the embodiment, the description will be made assuming that the state of blood flow is grasped from the degree of contrast of the contrast agent flowing into the liver parenchyma or heart muscle. 1 to 5 are system diagrams showing a first embodiment of an ultrasonic diagnostic apparatus according to the present invention. As shown in FIG. 1, the ultrasonic diagnostic apparatus includes an apparatus main body 11, which is detachably connected to the apparatus main body 11, transmits an ultrasonic wave to the subject P, and reflects the ultrasonic wave from the subject P with the ultrasonic wave. Ultrasonic probe 12 for receiving waves
And an operation panel 13 for giving various instructions and information of an operator or various setting conditions to the apparatus main body 11. The ultrasonic probe 12 is configured by arranging a large number of ultrasonic transducers made of a piezoelectric element such as a piezoelectric ceramic for converting an electric signal into an ultrasonic wave and conversely converting an ultrasonic wave into an electric signal. The operation panel 13 includes a trackball 13a, a keyboard 13b, an operation panel circuit 13c, and the like.

The apparatus main body 11 has a transmitting unit 21 and a receiving unit 22 connected to the ultrasonic probe 12. As shown in FIG. 2, the transmission unit 21 includes a rate pulse generator 21a, a transmission delay circuit 21b, and a pulser 21.
c. The rate pulse generator 21a is a rate frequency fr [Hz] (period: 1 / fr) for determining the transmission rate of ultrasonic waves (the number of ultrasonic pulses transmitted per second).
[Sec]), for example, a 5 kHz rate pulse. The rate pulse is distributed to the number of transmission channels and supplied to the transmission delay circuit 21b. The transmission delay circuit 21b is supplied with a timing signal for determining a delay time for each transmission channel from a controller 31, which will be described later, so that the rate pulse reduces the delay time required for determining the directivity of the ultrasonic wave. Is received for each channel and given to the pulser 21c as a trigger pulse. Then, in synchronization with the trigger pulse, a high-frequency voltage pulse having a center frequency fo is applied from the pulser 21c to the ultrasonic transducer of the ultrasonic probe 12 individually or in units of neighboring groups. In response to this voltage pulse,
An ultrasonic transducer provided at the tip of the ultrasonic probe 12 mechanically vibrates, whereby an ultrasonic pulse having a center frequency fo is generated and emitted to the subject P. The generation interval of the voltage pulse is controlled by the controller 31 as described later.

On the other hand, the ultrasonic pulse radiated from the ultrasonic probe 12 to the subject P propagates in the living body, and is reflected one after another on the discontinuous surface of the acoustic impedance during the propagation, and the ultrasonic pulse is reflected as an ultrasonic wave. It returns to the probe 12. The amplitude of the echo depends on the difference in acoustic impedance of the living body at the discontinuous surface that has been reflected. Further, an echo when the ultrasonic pulse is reflected by a moving blood flow or a surface such as a heart wall is subject to a frequency shift depending on the velocity component of the moving body in the beam direction due to the Doppler effect. . When the echo returns to the ultrasonic probe 12, the ultrasonic transducer at the tip of the ultrasonic probe vibrates mechanically, and the ultrasonic transducer generates a weak electric signal. This electric signal is taken into the reception unit 22 as a reception signal for each channel. As shown in FIG. 3, the receiving unit 22 has a preamplifier 22a, an A / D converter 22b, a reception delay circuit 22c, and an adder 22d. The electric signal from the ultrasonic probe 12 based on the ultrasonic echo introduced into the receiving unit 22 is first amplified by the preamplifier 22a for each channel. The amplified electric signal is converted from an analog signal to a digital signal by the A / D converter 22b, and is provided with a delay time necessary for determining the reception directivity by the reception delay circuit 22c, for example, the same as the transmission time. The addition is performed by the adder 22d. By this addition, one echo signal in which an echo component from a direction corresponding to the reception directivity is emphasized is obtained. With such transmission directivity and reception directivity, an overall ultrasonic beam for transmission and reception is formed.

Returning to FIG. 1, the apparatus main body 11 includes a rate signal calculation circuit 23, a receiver unit 24, and a B-mode DSC (digital scan converter) unit for sequentially processing echo signals received by the reception unit 22. 25,
It has an image memory circuit 26, a three-dimensional operation circuit 27, a Doppler unit 28, and a data synthesizer 29. Further, the display 30 for displaying images and the like, controls a central function for controlling the entire ultrasonic diagnostic apparatus, gives various instructions and information from an operator to each constituent unit of the apparatus main body 11, and operates an operation mode and a video mode. Controller 31, which controls the setting, drive timing, various calculations, and the like. The rate signal calculation circuit 23 has a memory function of holding an echo signal output from the reception unit 22, and has a function of performing, for example, a difference calculation or an averaging calculation on two or more rate pulse signals. I have.
The present circuit is used when executing a rate subtraction imaging (RSI) method described later, but when executing the B mode, the echo signal simply passes through the present circuit. Next, as shown in FIG.
4a, a logarithmic amplifier 24b, and an envelope detector 24c, which convert the intensity of the echo signal into a visual angle luminance signal to obtain a morphological information image (that is, a B-mode image) signal. The echo filter 24a is generally formed of a high-order digital filter, and passes only, for example, only harmonic components contained in a received signal. After the passed harmonic components are logarithmically amplified by the logarithmic amplifier 24b, the envelope detector 24c
, An envelope signal, that is, a signal of a B-mode image is obtained.

A method of generating an image by receiving a reflected wave of a harmonic generated in a process in which the ultrasonic beam propagates in the subject is based on harmonic imaging (Harmonic Imaging).
ing), this technique has a feature that a clear image can be obtained particularly at a medium distance (for example, 2 cm to 10 cm) from the ultrasonic probe, and has been frequently used recently. . Therefore, the receiver unit 24 functions as an effective band-pass filter when performing a so-called harmonic imaging method, and further has a purpose of shaping a signal shape and forming a uniform speckle pattern in the entire region of the image. used. However, when trying to draw a deep image, the image is generated by receiving the fundamental wave component of the echo signal.
4a needs to pass only the fundamental wave component of the received signal. The output of the receiver unit 24 is supplied to the B-mode DSC unit 25, and converts the raster signal sequence of ultrasonic scanning into a raster signal sequence of a video format.
That is, since the B-mode image signal output from the receiver unit 24 is a signal synchronized with the ultrasonic scanning, the B-mode image signal is synchronized with the standard television scanning by the DSC so that the signal can be displayed on the television scanning type display 30. Then, the scanning method is individually converted by reading. Then, the output of the B-mode DSC unit 25 is sent to the image memory circuit 26 to be recorded, and is also supplied to the data synthesizer 29. The data synthesizer 29 performs a synthesizing process such as arranging or superimposing information such as an image and setting parameters, and outputs the video signal to the display 30. As a result, a tomographic image representing the tissue shape of the subject is displayed on the display 30.

The echo signal received by the receiving unit 22 is also supplied to a Doppler unit 28. As shown in FIG. 5, the Doppler unit 28 includes a quadrature detector 28a, a clutter removing filter 28b, a Doppler shift frequency analyzer 2
8c, calculator 28d for calculating average speed, etc., DSC2
8e, a color processing circuit 28f, and the like. The quadrature detector 28a individually multiplies the echo signal supplied from the receiving unit 22 by a reference signal of the center frequency fo and a reference signal shifted by 90 degrees from the reference signal, respectively. By removing high frequency components, Doppler signals having shift frequency components are extracted. The Doppler signal mainly includes a high-frequency component subjected to frequency shift due to reflection from a fast moving body such as blood cells, and a low-frequency component subjected to frequency shift due to reflection from a slow moving body such as a heart wall. And is included.

The output of the quadrature detector 28a is supplied to a clutter removing filter 28b. Clutter removal filter 28
b functions as a high-pass filter, passes only high-frequency components (blood flow components) that have undergone frequency shift due to reflection of a fast moving body such as a blood flow, and is reflected mainly by a slow moving body such as a heart wall. This removes the low frequency component (clutter component) that has undergone the frequency shift. The Doppler signal that has passed through the clutter removal filter 28b and has become only a blood flow component is frequency-analyzed by a Doppler shift frequency analyzer 28c, and a shift frequency due to blood cells is obtained. further,
Based on the shift frequency, the calculator 28d calculates the blood flow velocity (average velocity) and its variance and mainly the blood flow rate (number of blood cells).
(The square of the amplitude of the Doppler signal) is calculated to obtain a signal of a blood flow information image (that is, a blood flow image). Since the signal of the blood flow information image is also a signal synchronized with the ultrasonic scanning, the signal is converted into a signal synchronized with the television scanning by the DSC 28e, and then supplied to the color processing circuit 28f, and the speed information of the color-processed blood flow and the like are output. Power information and the like are obtained as color flow data. The color flow data is synthesized by the data synthesizer 29 with a B-mode image representing the tissue shape of the subject, which is output from the B-mode DSC unit 25, and a blood flow information image with the B-mode image as a background is CFM ( Color flow mapping) image. This CFM
The image is displayed on the display unit 30 in the normal B-mode image portion in black and white, the blood flow information image portion in color, and the blood flow information image portion can be selectively displayed.

The output of the Doppler unit 28 is also sent to the image memory circuit 26 described above and recorded. The image memory circuit 26 has a memory for storing the output of the B-mode DSC unit 25 and the output of the Doppler unit 28 in the form of one or both of an ultrasonic scan raster signal sequence and a television scan raster signal sequence. Have. Therefore, this information can be read and used by the operator after the diagnosis is completed, for example. in this case,
The image data stored in the image memory circuit 26 is displayed on the display 30 via the data synthesizer 29. If the stored data is data synchronized with the ultrasonic scanning, the image data is transmitted through the DSC. After that, the data synthesizer 29
Is displayed on the display 30 via the. The image data stored in the image memory circuit 26 is supplied to a three-dimensional operation circuit 27 and used for constructing a three-dimensional image.
That is, the image data of a plurality of frames stored in the image memory circuit 26 is arranged in a three-dimensional space, and volume data having a depth in a direction perpendicular to the tomographic plane is constructed. The three-dimensional image constructed in this way is projected onto two-dimensional coordinates such as a bird's-eye view or a perspective view, and displayed on the display 30 via the data synthesizer 29. In addition,
An electrocardiograph (ECG) 14 is often used to display an electrocardiographic waveform of a subject along with an ultrasonic image. The electrocardiograph 14 attaches an electrode to the body surface of the subject P to obtain an electrocardiographic signal, sends the electrocardiographic waveform to the data synthesizer 29 via the heartbeat detection unit 32, and synthesizes it with an ultrasonic image. To be displayed on the display 30. The electrocardiographic signal is supplied to the transmitting unit 21 via the heartbeat detecting unit 32, and is used as a trigger signal for acquiring image data in synchronization with an electrocardiographic waveform, that is, for obtaining a so-called electrocardiographic synchronized image. That is, by supplying an electrocardiographic waveform to the transmission unit 21 and applying a voltage pulse from the pulsar 21c to the ultrasonic transducer of the ultrasonic probe 12 in synchronization with a desired time phase, synchronization with the desired time phase is achieved. Then, ultrasonic scanning is performed.

The basic circuit configuration as an embodiment of the ultrasonic diagnostic apparatus according to the present invention has been described above. Next, various characteristic operation sequences by the ultrasonic diagnostic apparatus will be described. FIG. 6 is a timing chart for explaining the transmission timing for acquiring an image in the ultrasonic diagnostic apparatus. FIG. 6A shows the concept of a conventional continuous transmission / reception mode. b)
3 illustrates a basic concept of an intermittent transmission / reception mode according to the present invention. In this figure, a large number of arrows arranged in an upward direction each indicate transmission / reception timing for acquiring an image for one frame. The intermittent transmission / reception mode shown in FIG. 6B will be referred to as a first embodiment of an operation sequence by the ultrasonic diagnostic apparatus of the present invention.

First, the conventional continuous transmission / reception mode shown in FIG. As is well known,
The number of images collected per unit time in the ultrasonic diagnostic apparatus is determined by the speed of the ultrasonic wave, the pulse repetition frequency, the scanning density,
It is determined depending on the scanning range and the like, and is usually 20 to 40 sheets (2
0 to 40 frames / sec). The frame generation interval is called a frame rate, and the normal frame rate R is about 1/20 to 1/40 second. Note that the frame rate R is the pulse rate fr described above.
And the number of pulse transmissions N required to generate one frame
R = fr / N [Hz] (N / fr seconds).
As described above, in the conventional transmission / reception mode, images are successively captured at the frame rate R continuously regardless of the number of frames to be obtained. However, in the present invention, intravenously to a subject, after injection of a contrast agent as a main component microbubbles, as shown in FIG. 6 (b), for example, two frames A, an image of only B, T _{A -B} and the image of frame A and frame B are acquired at the time interval of TB _-A (this time is the time during which the transmission of ultrasonic waves is stopped, ) To control the transmission / reception timing of the ultrasonic wave. Such an intermittent change to the transmission / reception mode of the present invention is performed by the operator using the keyboard 13 of the operation panel 13.
By issuing a command to the controller 31 using b or the like, the conventional continuous transmission / reception mode is appropriately changed. In addition, 2 of frame A and frame B
The time interval TA _-B of one frame is the same as the conventional frame rate (R = 1/20 to 1/40 seconds). On the other hand, the intermittent time TB _-A is 1/5 to 1 /
And about 10 seconds, it is preferable to set larger than the frame rate _{T A -B.} These values may be set in advance depending on other conditions of the ultrasonic diagnostic apparatus, or may be arbitrarily set by an operator.

Then, the ultrasonic probe 12 in which the ultrasonic transducers applied to the subject P are one-dimensionally arranged is slowly moved in a direction perpendicular to the tomographic plane, and the transmission and reception of ultrasonic waves are performed during that time. . So first,
An image of the frame A is acquired, and subsequently, an image of the frame B is acquired after TA _-B . Further, after the intermittent time TB _-A , an image of the next frame A is acquired, and subsequently, TA _-B
Thereafter, the operation is repeated so as to acquire the image of the next frame B. As described above, the image data of each frame acquired in the intermittent transmission / reception mode of the present invention is processed by each unit of the apparatus main body 11, and is processed by the image memory circuit 26.
Is sent to the three-dimensional operation circuit 27 via In the three-dimensional arithmetic circuit 27, independent three-dimensional reconstruction processing is performed on each of A and B using the data of the set of frame A and the data of the set of frame B shown in FIG. As described later, the three-dimensional image of the set of frame A and the three-dimensional image of the set of frame B formed in this way are
Are displayed in parallel with each other, or are superimposed and displayed.

Next, regarding the features of the two three-dimensional images, that is, the three-dimensional image of the set of frame A and the three-dimensional image of the set of frame B, independently acquired by the transmission / reception mode of the present invention as described above, This will be described with reference to FIG. FIG. 7 shows a cross section perpendicular to the tomographic plane of the subject P to which the ultrasonic probe 12 has been applied, and FIGS.
Moves the ultrasonic probe 12 in the direction perpendicular to the tomographic plane (arrow 1).
(2a direction) at a uniform speed. By the way, FIG. 7A shows the intermittent time TB _-A
5 shows the state of the contrast agent in the subject tissue when ultrasonic waves are repeatedly irradiated to acquire image data of frame A. That is, the region P101 in the subject tissue has already been subjected to the ultrasonic irradiation,
This indicates that the microbubbles of the contrast agent have disappeared. Since the intermittent time TB _-A is set to a time longer than the normal frame rate, the ultrasonic irradiation (scanning) for the frame A is performed on a new region P102 in which the microbubbles have not disappeared. Done. Therefore, an echo signal reflecting the perfusion is obtained from this area P102.

On the other hand, FIG. 7B shows that, after the frame A, an ultrasonic wave is irradiated after a time interval TA _- B,
5 shows the state of the contrast agent in the tissue of the subject when the image data is acquired. The time interval T _A-B, since a short time to about normal frame rate, the ultrasound probe 1
Insufficient time is required for 2 to move to the new region P102, and the region where the microbubbles have disappeared is again irradiated (scanned) with ultrasonic waves. Therefore, a perfusion echo signal cannot be obtained here. But,
Instead of the perfusion echo signal, an echo signal of a vascular blood flow having a high inflow rate can be observed. In the case or a very short time interval T _A-B, if irradiated sound pressure of the ultrasonic wave is relatively high, it will not be observed echo signal of the blood vessel the blood flow due to the contrast medium in the frame B. In other words, at this time, a B-mode image of a tissue unrelated to the contrast agent is obtained in the frame B. For these reasons, two separately formed three-dimensional images of the set of frame A and the set of frame B have the following features.
That is, the three-dimensional image formed by the set of the frame A is an image that reflects the perfusion dominantly, and the three-dimensional image formed by the set of the frame B has the morphology and tissue corresponding to that before the injection of the contrast agent. It is an image that reflects blood vessel blood flow dominantly. Observing both at the same time
This is useful for comparing the increase in brightness due to the contrast agent or for grasping the structure of the tissue corresponding to the distribution of the tissue blood flow. Needless to say, the time difference between the two data is very short, so that there is almost no difference in morphological movement, which is extremely convenient for comparing the two. Furthermore, the technique of the present invention is a very advantageous technique as compared with the conventional technique in which two data need to be acquired at a relatively long time interval before and after administration of a contrast agent. I can say.

Next, a second embodiment of the operation sequence by the ultrasonic diagnostic apparatus of the present invention will be described with reference to FIGS. The operation sequence according to the second embodiment is obtained by applying the present invention to a rate subtraction imaging (RSI) method. The RSI method is disclosed in Japanese Patent Application Laid-Open No. 8-336527 as an invention by the present inventor, and the validity of this method for two-dimensional tomographic images is described in "2-7-9 Ultrasound Imaging." Of Subtraction Imaging Using Transients of Agents, Naohisa Kamiyama
Proceedings of the Autumn Meeting of the Acoustical Society of Japan 1999, 1999
Year "has already been reported. Therefore, first, the RSI method will be briefly described. FIG. 8 shows a state in which sector scanning is being performed by the ultrasonic probe 12. Note that the scanning method is not limited to the sector scanning, but may be another scanning method such as linear scanning or convex scanning. In FIG. 8, it is assumed that a scanning area for one frame includes 100 scanning lines (rasters), and each scanning line is denoted by reference numerals (1), (2), (3), (4),. (19
8), (199) and (200).
Then, the ultrasonic beam is repeatedly transmitted to the subject P at a rate cycle of 1 / fr second, and an echo signal is received until the next transmission.

Therefore, every time the transmission and reception of the ultrasonic wave is repeated twice for the same scanning line, the scanning line is sequentially switched. Such an operation is performed one time from the first scanning line.
By performing the scanning up to the 00th scanning line, scanning for one frame is completed. Further, such scanning is similarly repeated for each frame. Accordingly, the adder 22d of the receiving unit 22 described with reference to FIGS. 1 and 3 synchronizes the detection data of the echo signal by the first transmission and the detection data of the echo signal by the second transmission with respect to the same point. And then added. Further, the output of the adder 22d is supplied to the rate signal operation circuit 23 in a time series for each rate. As shown in FIG. 9, the rate signal arithmetic circuit 23 is provided with an electronic switch 2 which is provided at an input terminal and is switched to two systems at a predetermined timing.
3a, line memories 23b and 23 provided for each system
c, and a difference calculator 23d for calculating a difference between the signals held in the line memories 23b and 23c. Therefore, the echo signal continuously supplied to the rate signal calculation circuit 23 for each rate is converted into an electronic switch 23a.
Signal 1 (received signal with odd number in FIG. 8) and signal 2 (received signal with even number in FIG. 8)
And assign them to the line memories 23b and 23c.
, And a difference calculator 23d calculates the difference between the two signals. Therefore, the difference signal S as the calculation result of the difference calculator 23d and the signal 2 before the calculation are output from the rate signal calculation circuit 23. The signal 1 before the calculation may be output instead of the signal 2. The signal S and the signal 2 (signal 1) are processed as separate signals in the receiver unit 24 and thereafter.

It should be noted here that signal 1 due to the first transmission and reception and signal 2 due to the second transmission and reception are:
There is a remarkable difference in the reflection phenomena from the contrast agent and the living tissue. That is, the first transmitted ultrasound
The signal 1 is reflected by the contrast agent and the living tissue. And
By the first ultrasonic irradiation, all or a part of the microbubbles as the contrast agent disappears. Therefore, in the signal 2 of the ultrasonic wave transmitted for the second time, the reflected component from the contrast agent is surely reduced, and the reflected component from the living tissue is the same as the signal 1. Therefore, the difference signal S obtained by taking the difference between the signal 1 and the signal 2 reflects the reflection data of only the lost contrast agent. The above is the basic operation of the RSI method. Therefore, as a second embodiment of the present invention, at intermittent time T _B-A predetermined frame rate (the time interval T
_AB ), two frames, that is, images of frame A and frame B are acquired. In this case, for both frames, transmission and reception of ultrasonic waves to the same scanning line are performed twice (N Times), echo signals are collected by the so-called RSI method. Therefore, a first signal A1 and a second signal A2 are obtained for the signal of frame A,
For the signal of frame B, a first signal B1 and a second signal B2 are obtained. Further, a difference signal AS between the first signal A1 and the second signal A2 of the frame A and a difference signal B between the first signal B1 and the second signal B2 of the frame B
S is also obtained. Here, as described above, an echo signal mainly reflecting the tissue and the perfusion is obtained in the frame A, and an echo signal mainly of the tissue and the vascular blood flow having a high inflow rate can be observed in the frame B. Therefore, the difference signal AS of the frame A represents only the perfusion from which the reflection signal from the living tissue has been removed, and the difference signal BS of the frame B represents the vascular blood flow from which the reflection signal from the living tissue has been removed. Is represented.

Next, a specific example of a three-dimensional image obtained by the first and second operation sequences by the above-described ultrasonic diagnostic apparatus of the present invention will be described with reference to FIGS. First, FIG. 10 shows that two three-dimensional images of frame A and frame B obtained by the first operation sequence (see FIG. 6B and FIG. And displayed. That is, FIG.
0 (a) is a three-dimensional image of the set of the frame A, and FIG.
0 (b) is a three-dimensional image of the set of frame B. FIG. 10C shows three-dimensional images of two frames, frame A and frame B, arranged on the display 30 with their spatial positions aligned. here,
The three-dimensional image of the frame A is configured by a tissue echo image including a micro blood flow (perfusion) of a tissue, while the three-dimensional image of the frame B is configured by a tissue echo image including a vascular blood flow. These are displayed in parallel and can be easily compared and observed. Further, according to an instruction from the operation panel 13 by the operator, rotation, enlargement,
In addition to the reduction, it is possible to display a general three-dimensional image by a known technique, such as cutting out an arbitrary cross section in the volume. As described above, in the harmonic imaging method, in addition to the method realized by a filter having a pass band including many harmonic components twice as much as the fundamental wave component of the echo signal, a method in which the phase is inverted is described. It can also be realized by a so-called pulse inversion method in which two transmission waves are transmitted twice and the received signal is added to cancel the fundamental wave component and extract a double harmonic. When this pulse inversion method is adopted, every time transmission and reception of ultrasonic waves are repeated twice for the same scanning line,
Scan lines are sequentially switched, and at this time, transmission is performed by transmitting a transmission wave having an inverted phase in two times, and reception is performed by adding the respective reception signals to cancel the fundamental wave component. The second harmonic is extracted.

Next, FIG. 11 shows the luminance of both pixels for each pixel based on the two image data of the set of frame A and the set of frame B by the harmonic imaging method shown in FIGS. 10 (a) and 10 (b). Is displayed on the display unit 30 as a frame difference image obtained by performing the difference operation on the frame. That is, FIG.
10A is a three-dimensional image of a set of frames A similar to FIG. 10A, and FIG. 11B is a three-dimensional image of a set of frames B similar to FIG. 10B. And FIG.
(C) is a three-dimensional difference image displayed on the display 30 by performing a difference operation for each pixel on the image data of the two frames, the frame A and the frame B, by aligning them spatially with each other. This difference image is a frame difference image (different from the rate difference image), and among the image data of the frame A and the frame B, the invariable tissue echo is canceled, and as a result, the contrast agent ( Only the echo signal of the microbubble is extracted and displayed. Therefore, the image shown in FIG. 11C is an image in which perfusion and vascular blood flow overlap. In addition,
The difference image may be obtained by calculating the difference between the image data of the frame A and the image data of the frame B in the image memory circuit 26 shown in FIG. 1 and then generating the three-dimensional image by the three-dimensional operation circuit 27. Alternatively, the two-dimensional image of the frame A and the frame B may be once generated in the three-dimensional arithmetic circuit 27, and then the difference image may be obtained in the three-dimensional arithmetic circuit 27.

FIG. 12 shows that the image of frame A is obtained by the first operation sequence, the image of frame B is obtained by the second operation sequence (see FIGS. 8 and 9), and these two images are superimposed. Is displayed on the display 30. That is, FIG.
11A is a three-dimensional image of a set of frames A obtained by the first operation sequence, similar to FIG. 11A.
FIG. 12B shows a three-dimensional image of a set of frame B obtained by the second operation sequence. The three-dimensional images of frame A and frame B are superimposed on each other with their spatial positions aligned. By doing so, an image as shown in FIG. In this case, an echo signal from the subject is collected by irradiating an ultrasonic beam for two consecutive frames at a frame rate shorter than the stop time after a predetermined stop time. Scans the scanning lines sequentially while irradiating the same scanning line once with an ultrasonic beam, and collects the signals as B-mode signals. On the other hand, the echo signal of the frame B is obtained by sequentially switching the scanning lines while repeating the irradiation of the ultrasonic beam on the same scanning line at least twice, and as described with reference to FIG. The two echo signals are collected as a difference signal S obtained by performing a difference operation. Then, the echo signals of the two sets of frames, frame A and frame B, form independent three-dimensional images. Therefore, the three-dimensional image of the frame A is constituted by a tissue echo image including many perfusion echoes, while the three-dimensional image of the frame B is a three-dimensional image of only the blood vessel blood flow. These are shown in FIG.
As shown in (c), it is superimposed and displayed, and the structure of the blood vessel blood flow can be very clearly observed in the tissue echo image including perfusion, which can greatly contribute to the diagnosis of the vascular system. In order to enhance the visibility of the discrimination between the two, it is preferable that one or both of the images of the frame A and the frame B are color-coded and displayed on a different hue scale. 11 (c) and FIG.
As shown in FIG. 13C, when a three-dimensional image of two frames A and B is superimposed and displayed as shown in (c), an interleave obtained by cutting a tissue echo image including a perfusion of frame A at a desired cross section as shown in FIG. As an image, this is frame B
When the three-dimensional image of the blood vessel blood flow is superimposed and displayed while adjusting the spatial position to each other, it becomes easier to grasp the tissue structure and the blood vessel structure.

FIG. 14 shows an image obtained by obtaining images of frames A and B by the second operation sequence, and superimposing the images on the display 30. That is, the RSI described in FIG.
Scan by the method. Then, for the echo signal of frame A, the first signal obtained from the rate signal arithmetic circuit 23
A signal A1 and a difference signal AS between the second signal A2 and a second signal A2 (or a first signal A1) that does not take a difference are sent to the three-dimensional operation circuit 27, respectively.
A three-dimensional image of each of the difference signal SA and the second signal A2 is generated. Therefore, the three-dimensional image based on the second signal A2 is
A tissue echo image including perfusion as shown in FIG. 14A is obtained.
Only the perfusion echo image from the contrast agent as shown in FIG. On the other hand, as for the echo signal of the frame B, only the difference signal BS between the first signal B1 and the second signal B2 obtained from the rate signal calculation circuit 23 is sent to the three-dimensional calculation circuit 27, and the three-dimensional image is obtained. Generate. Therefore, in this three-dimensional image, only the blood vessel blood flow as shown in FIG. 14C is visualized. As a result, FIG.
(A), (b), and (c), three different types of images are obtained. These images are superimposed on each other with their spatial positions adjusted and displayed on the display 30. Therefore, FIG.
As shown in (d), a three-dimensional image in which perfusion and vascular blood flow are fused is obtained. In this case, for example, FIG.
The image component of FIG. 14A is displayed in gray scale, and the image component of FIG. 14B is superimposed on the gray scale, and the image component of FIG. 14C is superimposed on the red scale. If they are displayed, they can be easily identified.

As described above, the first and second operation sequences in the first embodiment of the ultrasonic diagnostic apparatus according to the present invention shown in FIG. 1 and various modes of the image display mode in these operation sequences. Although described, it is not necessarily limited to the described items. For example,
By synchronizing the above operation sequence with the ECG,
It is also possible to capture three-dimensional data. That is,
By supplying an electrocardiographic signal from the electrocardiograph 14 to the transmitting unit 21 via the heartbeat detecting unit 32 for an organ whose shape changes greatly due to pulsation such as the heart, as shown in FIG. for each trigger Arutoki phase synchronized with the electrocardiogram waveform shown by the frame rate T _a-B as shown in FIG. 15 (b), performs transmission and reception of ultrasonic waves a, B2 frames, the same time phase What is necessary is just to acquire a plurality of image data while changing the scanning plane. At this time, the cycle of the pulsation substantially corresponds to the intermittent time TB _-A . Then, the collected image data may be processed in the same manner as the process described above.

In the above description, the intermittent time T
_Although transmission and reception for two frames A and B are performed at the frame rate T _{AB with B-} A, transmission and reception for two or more frames may be performed. That is, the main purpose of acquiring two volume data in the present invention is to visualize an image in which perfusion can be predominantly rendered and an image in which vascular blood flow can be predominantly rendered. This is because it is necessary to completely eliminate the contrast agent (microbubbles) filling the tissue by irradiation of ultrasonic waves. Therefore, for example, irradiation of ultrasonic waves for four frames is performed, and irradiation of ultrasonic waves for the second and third frames is performed for the purpose of eliminating the contrast agent.
If the frame is acquired as data corresponding to frame B, this becomes an image that can predominantly depict the vascular blood flow.
Of course, the first frame is acquired as data corresponding to frame A, and this is an image that can render perfusion superiorly. Further, the RSI method to which the present invention described as the second operation sequence is applied can be replaced with a color Doppler method for displaying the blood flow in color. However, since the color Doppler method requires transmission of 10 data or more per scanning line, there is a problem that the frame rate is reduced. Therefore, it is effective to draw a blood vessel blood flow by the RSI method. According to the first embodiment of the present invention described above, a three-dimensional image mainly containing information on tissue and perfusion and a three-dimensional image mainly containing information on tissue and vascular blood flow are approximately Since they can be acquired and displayed at the same time, it is possible to observe the state of blood flow in an organ with a higher information amount than before as a three-dimensional image.

Next, the second embodiment of the ultrasonic diagnostic apparatus according to the present invention will be described.
The embodiment will be described with reference to FIGS. FIG. 16 is a system diagram showing a second embodiment of the ultrasonic diagnostic apparatus according to the present invention, and is different from the system diagram of the first embodiment shown in FIG. A coordinate memory 42 and a distance calculation circuit 43 are added, and other configurations are the same as those in FIG. Therefore, in FIG. 16, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description of those parts will be omitted. FIG. 17 illustrates an example of the case where three-dimensional scanning is performed in the present embodiment. This three-dimensional scan is shown in FIG.
As shown in FIG. 7A, the scanning surface of the ultrasonic probe 12 is moved in a three-dimensional area of the subject P, and echo signals from each point in the three-dimensional area are collected. That is, as shown in FIG. 17B, the Z axis of the orthogonal coordinate system is set as an axis parallel to the body axis of the subject P, and the X axis is a horizontal direction perpendicular to the body axis of the subject P ( When the Y axis is the axis in the front-rear direction (thickness direction) orthogonal to the direction perpendicular to the body axis of the subject P, the ultrasonic probe 12 is centered on the X axis of the subject P. By operating in the rotation direction α, the rotation direction β about the Y axis, and the rotation direction γ about the Z axis, three-dimensional data is collected. In this case, the position of the ultrasonic probe 12 on the surface of the subject P is defined as a reference position P0.

Therefore, the position detector 41 is a mechanical detector integrally attached to the ultrasonic probe 12, or a magnetic sensor or the like in which only the detection section is directly attached to the ultrasonic probe 12, for example. Ultrasonic probe 12
Is to detect spatial position information. This position detector 41 is provided with a coordinate P0 of the reference position of the ultrasonic probe 12.
(X0, y0, z0) and the angle θα (X
Rotation angle about the axis), angle θβ (rotation angle about the Y axis), angle θγ (rotation angle about the Z axis)
, And these detection signals (position information) are supplied to the coordinate memory 42 and stored. The position information stored in the coordinate memory 42 is read out by the distance calculation circuit 43, and the distance between the plurality of tomographic images captured while moving the ultrasonic probe 12 is obtained. Is written to the circuit 26 so as to be added to the data of the image recorded in the. The data of the tomographic images sequentially collected and recorded in the image memory circuit 26 are sent to the three-dimensional operation circuit 27, and are arranged in the three-dimensional space based on the corresponding position information and the swing angle of the scanning line. Construct volume data according to the real space. And the reconstructed 3D image is
The data is projected onto two-dimensional coordinates such as a bird's-eye view or a perspective view, and is superimposed on necessary parameter values, electrocardiographic waveforms, and the like via the data synthesizer 29 and displayed on the display 30.

Here, the operation of the distance calculation circuit 43 will be described in detail with reference to FIG. FIG.
Position the ultrasonic probe 12 in the direction perpendicular to the tomographic plane (arrow 12b).
Direction) while moving in parallel to the plurality of tomographic planes S1, S
FIG. 4 is a conceptual diagram viewed from a direction perpendicular to a tomographic plane when a tomographic image is obtained at 2,..., Si-1, and Si.
The distance between the tomographic planes S1 and S2 is indicated by d2,
Hereinafter, the distance between the tomographic planes Si-2 and Si-1 is sequentially referred to as d.
i-1 and the distance between the tomographic plane Si-1 and Si are indicated by di. As is clear from this figure, when the operator moves the ultrasonic probe 12 by hand, it is easily assumed that the distance between the respective tomographic planes slightly varies even if the operator thinks that the ultrasonic probe 12 is moving at a uniform speed. Is done. The position information of these tomographic planes is detected by the position detector 41, and the position information from the position detector 41 is sent to the distance calculation circuit 43 via the coordinate memory 42. At this time, the position information is monitored in real time, and the distance di + 1 between the previous tomographic plane Si + 1 and the tomographic plane Si + 1 predicted by the current position of the ultrasonic probe 12 (at this time, ultrasonic waves have not been irradiated yet) is determined. calculate. Then, the calculated distance di + 1 is compared with a predetermined threshold value D, and when it is determined that the distance di + 1 is larger than the threshold value D (di + 1> D), the distance calculation circuit 43 sends the controller 31 Send a signal to inform it. Therefore, the controller 31 sends a signal to the rate pulse generator 21a of the transmission unit 21 at this timing, and as a result, the ultrasonic probe 12 irradiates the subject P with ultrasonic waves.

A position detector for detecting such spatial position information of the ultrasonic probe is provided, and every time the ultrasonic probe moves a predetermined distance, ultrasonic scanning is executed based on the position information from the position detector. A method of collecting three-dimensional data by using the method has already been proposed by the present inventor as Japanese Patent Application No. 11-143454. Therefore, the second embodiment of the present invention is realized by applying an intermittent transmission / reception operation sequence to this method. That is, it is determined that the moving distance di + 1 of the ultrasonic probe 12 is larger than the threshold value D, and the two frames already described, that is, the frame A and the frame B, are provided at one timing of ultrasonic irradiation. It is assumed that ultrasonic scanning corresponding to the above is performed. Here, the distance between the frame A and the frame B (that is, the frame rate R = T _A−B = 1 / 20-1 / 1/2)
The moving distance of the ultrasonic probe 12, which moves during about 40 seconds, is extremely shorter than di, and these two frames are almost included in the tomographic plane Si. Therefore, it is omitted to separately describe the frame A and the frame B on each tomographic plane. The threshold D is intermittent time _{T B-A}
The transmission frequency and transmission sound pressure of the ultrasonic wave or the sound of the ultrasonic probe depend on how much the contrast agent (microbubbles) in the spatial region disappears by one ultrasonic irradiation. It also changes depending on the focus of the lens.
Therefore, the threshold value D is set to an optimum value in advance based on the system specifications of the ultrasonic diagnostic apparatus, but can be set arbitrarily by the operator via the operation panel 13.

The processing of the signal after the reception of the echo signal by the receiving unit 22 and the formation of the three-dimensional image are the same as those in the first embodiment, so that the description thereof will be omitted. The three-dimensional image formed by the set A is a tissue echo image that reflects the perfusion dominantly, and the three-dimensional image formed by the set B is a tissue echo image after the microbubbles as the contrast agent disappear. And an image reflecting the form of the blood flow. Then, two formed three-dimensional images of the set of frame A and the set of frame B are displayed on the display 30 in the same manner as in FIGS.
As described in detail above, according to the second embodiment of the present invention, echo data can be collected at necessary and sufficient intervals to construct a three-dimensional image. Then, it is possible to selectively scan an area filled with microbubbles as a contrast agent, and to obtain a tomographic image having a high echo intensity. Similarly, regardless of the moving speed of the ultrasonic probe 12, the echo luminance by the contrast agent can be uniformly acquired in all the tomographic images.

Next, the third embodiment of the ultrasonic diagnostic apparatus according to the present invention will be described.
The embodiment will be described with reference to FIGS. 19 to 21. FIG. In this embodiment, as shown in FIG. 19, an ultrasonic probe 12 in which ultrasonic transducers 12c such as piezoelectric ceramics are two-dimensionally arranged is used as the ultrasonic probe 12. As a so-called 2D array ultrasonic probe in which such ultrasonic transducers 12c are two-dimensionally arranged, for example, a 256 × 256 channel having the same number of channels as a one-dimensional array in two dimensions has already been developed. By using this ultrasonic probe, it is possible to scan an arbitrary cross section in the space of the subject. In the present embodiment, such a 2D array ultrasonic probe may be used.
The so-called 1.5D array or 1.75D array ultrasonic probe (for example, the number of channels in the width direction and the number of channels in the thickness direction (lens direction)) is smaller than that in the one-dimensional array as shown in FIG. 256 × 1
(6 channels). In addition,
The 1.5D array ultrasonic probe cannot scan an arbitrary cross section, but can scan ultrasonic waves by changing the elevation direction (elevation direction) with the ultrasonic probe fixed. Therefore, it is possible to obtain images of cross sections having different elevation angles. In this case, the device body 11
The overall configuration is the same as that shown in FIG. 1, but the operation sequence is different, and a simple continuous scanning format corresponding to the conventional system as shown in FIG. 20 is employed.

That is, the data of the set of frame A and the data of the set of frame B are alternately and continuously obtained at a predetermined frame rate. At this time, as shown in FIG. In frame B and frame B, ultrasonic waves are emitted in directions with different elevation angles Θ, and echo signals from each direction are acquired. In FIG. 21, regions P101, P10
2 indicates the state of the contrast agent in the tissue of the subject similarly to FIG. 7, and in the region P101, the microbubbles of the contrast agent have disappeared due to the ultrasonic irradiation already performed. And a region P102 indicates a new region in which the microbubbles have not disappeared. Therefore, for the set of frame A, the area P102 where the microbubbles are always newly present is set.
Is irradiated with an ultrasonic wave, and an echo signal that reflects perfusion dominantly is obtained. On the other hand, in the group of frame B, the region P101 where the microbubbles have always disappeared.
Is irradiated with an ultrasonic wave, so that an echo signal that reflects blood vessel blood flow dominantly is obtained. That is, similarly to the first embodiment, it is possible to acquire an image in which perfusion is predominantly reflected and an image in which vascular blood flow is predominantly reflected almost simultaneously. Therefore, two three-dimensional images of the set of the frame A and the set of the frame B are individually formed in the same manner as described in the first embodiment, and FIG.
Is displayed on the display 30 as shown in FIG. Although the spatial position of the cross section is different between the set of frame A and the set of frame B at this time, when the three-dimensional image is generated, correction is performed based on the elevation angle を, and the spatially corresponding points match. Shall be allowed. The elevation angle Θ can be arbitrarily changed by the operator. As described above, according to the third embodiment, similarly to the first and second embodiments, it is possible to acquire a perfusion superior image and a vascular blood flow superior image almost simultaneously. In addition, since the spatial positions of the set of frame A and the set of frame B can be separated without changing the pulse rate, it is possible to reliably obtain an image in frame B by scanning the area where the microbubbles have disappeared.

[0044]

As described above in detail, according to the present invention, a three-dimensional image mainly including perfusion information,
Since three-dimensional images containing mainly blood vessel blood flow information can be acquired and displayed almost at the same time, it is necessary to observe the state of blood flow in organs with a higher amount of information than before as a three-dimensional image. And an ultrasonic diagnostic apparatus that contributes to more advanced diagnosis is provided.

[Brief description of the drawings]

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

FIG. 2 is a system diagram showing an outline of a transmission unit in FIG. 1;

FIG. 3 is a system diagram showing an outline of a receiving unit in FIG. 1;

FIG. 4 is a system diagram showing an outline of a receiver unit in FIG. 1;

FIG. 5 is a system diagram showing an outline of the Doppler unit in FIG. 1;

FIG. 6 is a timing chart for explaining the transmission / reception timing for acquiring an image by comparing the transmission timing with the present invention.

FIG. 7 is an explanatory diagram for explaining features of two images acquired in the present invention.

FIG. 8 is an explanatory diagram shown to explain an operation sequence of the rate subtraction imaging method.

FIG. 9 is a system diagram showing an outline of a rate signal operation circuit in FIG. 1;

FIG. 10 is a diagram showing a first display mode of a three-dimensional image obtained by the present invention.

FIG. 11 is a diagram showing a second display mode of a three-dimensional image obtained by the present invention.

FIG. 12 is a diagram showing a third display mode of a three-dimensional image obtained by the present invention.

FIG. 13 is a diagram showing a fourth display mode of a three-dimensional image obtained by the present invention.

FIG. 14 is a diagram showing a fifth display mode of a three-dimensional image obtained by the present invention.

FIG. 15 is an explanatory diagram illustrating an embodiment in which the present invention is performed in synchronization with an electrocardiogram.

FIG. 16 is a system diagram showing a second embodiment of the ultrasonic diagnostic apparatus according to the present invention.

FIG. 17 is an explanatory diagram of three-dimensional scanning according to the second embodiment of the present invention.

FIG. 18 is an explanatory diagram of an operation of the distance calculation circuit according to the second embodiment of the present invention.

FIG. 19 is an explanatory diagram of an ultrasonic probe in which ultrasonic transducers are two-dimensionally arranged.

FIG. 20 is an explanatory diagram of a scanning format according to the third embodiment of the present invention.

FIG. 21 is an explanatory diagram for explaining features of two images acquired in the third embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 11 apparatus main body 12 ultrasonic probe 13 operation panel 21 transmission unit 22 reception unit 23 rate signal operation circuit 24 receiver unit 25 B-mode DSC unit 26 image memory circuit 27 three-dimensional operation circuit 28 Doppler unit 29 data synthesizer 30 display 31 controller TA _-B frame rate TB _-A intermittent time (stop time)

Claims (15)

[Claims] An object to which an ultrasonic contrast agent containing microbubbles as a main component is administered is three-dimensionally scanned with an ultrasonic beam to obtain a three-dimensional image of the scanning area and display the image. An ultrasonic diagnostic apparatus that repeatedly emits an ultrasonic beam for at least two consecutive frames at a predetermined frame rate shorter than the stop time after a predetermined stop time to collect echo signals from the subject. A set of echo signals of a first frame and a set of echo signals of a second frame in the continuous frames,
An ultrasonic diagnostic apparatus, comprising: three-dimensional image processing means for forming independent three-dimensional images. 2. A three-dimensional scan with an ultrasonic beam is performed on an object to which an ultrasonic contrast agent containing microbubbles as a main component is administered to obtain a three-dimensional image of the scan area and display the image. Irradiating the same scanning line with at least two ultrasonic beams.
The scan lines are sequentially switched while repeating the above, to collect echo signals for one frame, and at a predetermined stop time, at a predetermined frame rate shorter than the stop time, an ultrasonic beam for at least two consecutive frames is formed. Transmitting / receiving means for repeatedly irradiating and collecting echo signals from the subject; difference calculating means for obtaining a difference signal by calculating a difference between two echo signals related to the same scanning line collected by the transmitting / receiving means; Independent three-dimensional images are obtained from a set of difference signals obtained by the difference calculation means of a first frame of a continuous frame and a set of difference signals obtained by the difference calculation means of a second frame. An ultrasonic diagnostic apparatus comprising: a three-dimensional image processing unit that forms the image. 3. A three-dimensional scan of an object to which an ultrasonic contrast agent containing microbubbles as a main component is administered by an ultrasonic beam through an ultrasonic probe to form a three-dimensional image of the scan area. An ultrasonic diagnostic apparatus that obtains and displays the image; a position information detecting unit that detects spatial position information of the ultrasonic probe; and a moving distance of the ultrasonic probe detected by the position information detecting unit is a predetermined distance. When the threshold is exceeded,
Transmitting / receiving means for repeatedly irradiating an ultrasonic beam for at least two consecutive frames at a predetermined frame rate to collect echo signals from the subject; and transmitting and receiving echo signals of a first frame of the consecutive frames. From the set and the set of echo signals of the second frame,
An ultrasonic diagnostic apparatus, comprising: three-dimensional image processing means for forming independent three-dimensional images. 4. An object to which an ultrasonic contrast agent containing microbubbles as a main component is administered is scanned with an ultrasonic beam through an ultrasonic probe having an ultrasonic transducer arranged in a two-dimensional manner. In an ultrasonic diagnostic apparatus that obtains a three-dimensional image of a scanning region and displays the image, an echo signal from the subject is repeatedly irradiated with an ultrasonic beam for at least two frames having different elevation angles at a predetermined frame rate. Transmitting / receiving means for collecting; and three-dimensional image processing means for forming independent three-dimensional images from a set of echo signals of the first frame and a set of echo signals of the second frame having different elevation angles. An ultrasonic diagnostic apparatus, comprising: 5. The apparatus according to claim 1, wherein acquisition of echo signals for at least two frames by said transmission / reception means is performed in synchronization with a desired time phase of an electrocardiogram of the subject. An ultrasonic diagnostic apparatus according to item 1. 6. The apparatus according to claim 1, wherein signals of the first frame and the second frame are collected as signals of different video modes. Ultrasound diagnostic device. 7. The ultrasonic diagnostic apparatus according to claim 6, wherein the different video modes are a B mode and a color Doppler mode. 8. From the set of echo signals of the first frame and the set of echo signals of the second frame, each independent three-dimensional image formed by the three-dimensional image processing means is spatially separated from each other. The ultrasonic diagnostic apparatus according to any one of claims 1 to 7, wherein the ultrasonic diagnostic apparatus is displayed in a state where the positions are aligned and arranged in parallel. 9. An independent three-dimensional image formed by the three-dimensional image processing means is spatially mutually separated from the set of echo signals of the first frame and the set of echo signals of the second frame. The ultrasonic diagnostic apparatus according to any one of claims 1 to 7, wherein the ultrasonic diagnostic apparatus is displayed in a superimposed state. 10. An independent three-dimensional image formed by the three-dimensional image processing means is spatially separated from the set of echo signals of the first frame and the set of echo signals of the second frame. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus displays a difference image obtained by performing a difference operation for each pixel by adjusting a position. 11. The three-dimensional image processing means includes processing means for forming a three-dimensional image independent of a set of one of the echo signals before the difference operation of the first frame is performed. 3. The ultrasonic diagnostic apparatus according to claim 2, wherein the independent three-dimensional images formed by the original image processing means are superimposed and displayed with their spatial positions aligned. 12. A three-dimensional scan of an object to which an ultrasonic contrast agent containing microbubbles is administered by an ultrasonic beam to obtain a three-dimensional image of the scan area and display the image. In the ultrasonic diagnostic apparatus, a predetermined stop time is set at a predetermined frame rate shorter than the stop time to irradiate an ultrasonic beam for two consecutive frames to collect echo signals from the subject. In the first frame, the scanning lines are sequentially switched while irradiating the same scanning line once with the ultrasonic beam.
A frame for transmitting and receiving the ultrasonic beam to the same scanning line at least twice, and sequentially switching the scanning line; and a set of echo signals of the first frame are collected as B-mode signals, A set of echo signals of the second frame is collected as a difference signal obtained by performing a difference operation between two echo signals related to the same scanning line, and a three-dimensional image processing unit that forms independent three-dimensional images is provided. ,
An ultrasonic diagnostic apparatus comprising: a display unit configured to display the independent three-dimensional images formed by the three-dimensional image processing unit in a manner that the three-dimensional images are spatially aligned with each other and overlap each other; 13. The signal according to claim 1, wherein the signal of the first frame and / or the signal of the second frame contain a large number of harmonic components with respect to a fundamental component of the echo signal. The ultrasonic diagnostic apparatus according to claim 1. 14. A three-dimensional image formed from a set of echo signals of the first frame by the three-dimensional image processing means as an interleaved image cut at a desired cross section. An ultrasonic diagnostic apparatus according to any one of claims 13 to 13. 15. The apparatus according to claim 1, wherein at least one of the independent three-dimensional images formed by said three-dimensional image processing means is displayed in color.
The ultrasonic diagnostic apparatus according to any one of the above.