JP2001238884A - Method of quantitative analysis on aspect of tissue by ultrasound diagnostic equipment and ultrasound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain quantitative information on the degree of deviation of shapes of the particular tissue from normal accurately, automatically, and easily. SOLUTION: The ultrasound diagnostic equipment have a mechanism that computer-enhanced cross-sectional images are obtained by emitting ultrasound pulse to an examinee's body. This equipment is provided with following means: Means (13, 40, 36, 26) set up areas for analysis on a part of the cross-sectional images. Means (12, 21, 22, 23) pick up echo signals reflected at parts of the examinee's body after ultrasound pulses are emitted to parts of the examinee's body, which are the areas for analysis, according to the emitting conditions for quantitative analysis. Means (24,31-33) perform quantitative analysis on aspects of tissue depending on reflected echoes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic imaging apparatus and method for obtaining an ultrasonic image in an object based on an echo signal generated by an ultrasonic wave applied to the object, and more particularly, to the intensity of the echo signal. The present invention relates to an ultrasonic diagnostic apparatus having a function of quantitatively analyzing a tissue property of a subject from distribution and a quantitative analysis method.

[0002]

2. Description of the Related Art Medical applications of ultrasonic signals are diversified, and an ultrasonic diagnostic apparatus is one of them.

[0003] The mainstream of this ultrasonic diagnostic apparatus is of a type in which a tomographic image of a soft tissue of a living body is obtained using an ultrasonic pulse reflection method. This imaging method can obtain a tomographic image of tissue non-invasively, and it can be displayed in real time compared to other medical modalities such as X-ray diagnostic equipment, X-ray CT scanner, MRI equipment, and nuclear medicine diagnostic equipment, It has many advantages, such as a small and relatively inexpensive device, no exposure to X-rays and the like, and blood flow imaging based on the ultrasonic Doppler method. For this reason, it is widely used in the diagnosis of the circulatory organ (heart), abdomen (liver, kidney, etc.), mammary gland, thyroid gland, urology, obstetrics and gynecology. In particular, it is possible to observe the heart beat and the movement of the fetus in real time with a simple operation just by applying the ultrasonic probe to the body surface, and it is possible to repeatedly perform the examination because there is no worry about X-ray exposure, It also has various advantages such that the ultrasonic diagnostic apparatus can be easily moved to the bedside for easy examination.

Further, currently used ultrasonic diagnostic apparatuses usually have various measurement functions. The term "measurement" as used herein refers to quantifying a physical event in a subject, and the measurement result is converted into a numerical value itself and / or a quantity such as color or luminance corresponding to the numerical value and presented. You.

[0005] The main measuring functions mounted on the conventional ultrasonic diagnostic apparatus are listed below. Shape measurement: With this shape measurement function, for example, the size of a liver tumor, the wall thickness of a myocardium, the size of a fetus, and the like are measured. Velocity measurement: The velocity measurement function includes, for example, blood flow velocity of an artery using the Doppler method and blood flow velocity mapping of blood vessels in the liver using the color Doppler method. Measurement of volume, flow rate, etc .: With this measurement function, for example,
The volume of the heart chamber is estimated based on several lengths in the heart chamber, and the blood flow is measured from the temporal change of the signal intensity of the contrast agent.

Naturally, the measurement values obtained by such measurement often serve as useful information for evaluating the severity of the disease. For example, information such as the size of the tumor or the degree of regurgitation in the blood vessel immediately indicates the need for treatment.

[0007] On the other hand, there is a lot of measurement information which is not for directly evaluating a disease but is indirectly useful for diagnosing the health condition of a subject. This is more common as a familiar measurement in everyday life. For example, the height, weight, blood pressure, or various numerical values obtained by a blood test of the subject fall into this category.

[0008] Further, as a matter that is different from such various measurement functions, there is a diagnosis close to quantification based on empirical judgment of a doctor. This valuable diagnosis can be found everywhere in the medical field. For example, when an ultrasound diagnostic image of the liver is presented, visually observe the "uniformity" of the speckle pattern, and if the non-uniform appearance is strong,
He has been diagnosed with suspected abnormal liver cirrhosis. Until now, the “abnormality” as in the case of this example has not been quantified, and the diagnosis is based on the empirical judgment of the doctor.

[0009] As described above, it is intended to objectively and scientifically elucidate and quantify the question of what kind of recognition pattern of humans is used to make a diagnosis based on the empirical judgment of a doctor. Some research has already been done. For example, (1) Yamaguchi T, Hachiya H,
“Modeling of the Cirrhotic
LiverConsidering the Li
ver Lobe Structure ", Jp
n. J. Appl. Phys. Vol. 38 (199
9) pp. 3382-3392; (2) Otsuka, Yamaguchi, Hachiya: "Simulation of Ultrasound b-Mode Image of Lesioned Liver by Simulation", IEICE Tech.
6-16 (1996-06) pp. Articles such as 15-22 are known.

In any case, providing such a diagnosis based on the empirical judgment of a physician as an objective measurement method and a measurement value is expected to be useful for the diagnosis.

Here, a basic method of quantification based on the contents of the above research paper will be described.

FIGS. 15A and 15B schematically show tomographic images of the liver. FIG. 2A is a tomographic image of a normal person having no abnormality in the liver, and a pattern called a speckle pattern of the liver looks relatively uniform. Speckle pattern is a phenomenon that when countless scatterers in the liver are distributed with a fineness equal to or less than the resolution of ultrasound, countless superposition of scattered waves causes high and low portions of the echo signal intensity to occur. It is. This is a physical phenomenon similar to a so-called interference fringe,
It is known that white dots appearing in tomographic images do not directly reflect structures.

On the other hand, FIG. 2B schematically shows a tomographic image of an abnormal liver having a disease, and the speckle pattern has a non-uniformity compared to the image of FIG. Is increasing. A typical case in which this type of image is obtained is cirrhosis. As the cirrhosis progresses, the number and size of the nodules both increase anatomically, and an echo pattern that gradually reflects those structures (such as nodules) appears. Cirrhotic liver is not a disease in itself. However, it is very important to find cirrhosis liver early because cirrhosis liver is known to cause liver cancer thereafter.

FIG. 16A shows a probability density distribution of luminance values of echo signals reflected from a normal liver.
From a stochastic and statistical point of view, if the scatterers are randomly distributed, the probability density distribution P (x) of the amplitude value which is the intensity of the echo signal reflected from those scatterers
Is

According to a Rayleigh distribution represented by P (x) = (x / σ ² ) exp (−x ² / 2σ ² ). Here, σ ² represents the variance, and the average is normalized to 0.

If the liver is normal, it can be assumed that the scatterers in the liver are present at random. Therefore, the probability density function of the image luminance (amplitude) representing the liver is Rayleigh distribution as shown in FIG. Will be exhibited. However, when an abnormality such as a nodule occurs in the liver as described above, the speckle pattern reflects a structure and cannot be said to be random. As a result, the probability density function of luminance (amplitude) deviates from the Rayleigh distribution as shown in FIG.

As described above, it is possible to determine whether the liver is normal or abnormal by observing the general shape of the probability density distribution curve of the intensity of the echo signal.

According to the paper cited above, an error between the probability density distribution obtained by actual measurement and the Rayleigh distribution as a theoretical value is used as a criterion for evaluation.

[0018]

According to the contents of the above-mentioned paper, the degree of similarity between the probability density distribution concerning the intensity distribution of the echo signal and the Rayleigh distribution is considered from the viewpoint of the normal / abnormality of the organ tissue. It has been demonstrated that quantification is possible.

However, a problem regarding the quantification described in this paper is "How to accurately determine the probability density distribution." As already known, in order to find out how much a certain event has a probability distribution, the number of samples (the number of samples) needs to be sufficiently large. For example, the probability of rolling a dice to get a "1" is 1/6, but when the number of samples is small, the probability of such a probability actually increases. Only when the number of samples increases, does the probability approach 1/6. For example,
If the player shakes only six times, the probability that the number "1" will appear is 0 or 3 times. However, if the player shakes 6000 times, the probability approaches 1/6, such as 988 times.

However, according to the quantification method described in the above-mentioned article, the sample for obtaining the probability density distribution is a tomographic image (gray scale image which is a B-mode image) based on ultrasonic diagnosis recorded on a video tape or the like. Had been obtained from. This may cause the following problems.

(1) Various problems of accuracy caused by using a luminance image Since a luminance image is composed of image data which has been logarithmically compressed (compression processing of echo data by logarithmic calculation), image data is used for quantification. In order to return the luminance value of to the linear characteristic before compression, antilogarithmic conversion must be performed. As long as digital data is handled, errors occur in its processing.

In order to perform a significant antilog transformation,
The luminance gray scale on the device must be guaranteed to be linear. However, in practice, it is not always linear. Rather, luminance is often processed on a curved scale in order to enhance visibility.

Furthermore, the luminance characteristic when recording image data on a video tape is not actually linear, and it is inevitable that the luminance characteristic slightly changes depending on the type of video recorder and the type of video tape. Even when luminance saturation occurs during recording, accurate evaluation is no longer possible.

(2) Problems caused by the number of samples In the case of a video image, each video pixel corresponds to a sample. The normal video format is 640x480
= Consisting of about 300,000 pixels. However, since the evaluation target is a local region in the organ tissue, the number of samples is actually about 1000 pixels at most. in addition,
Attention must be paid to setting a local region avoiding high-brightness signals of the blood vessel wall and the organ boundary so as not to include them in the sample. For this reason, it is often necessary to further reduce the number of samples.

On the other hand, as shown in FIG. 17, the problem caused by the relationship between the "scanning line of the ultrasonic wave" and the "scanning line of the video image" must be emphasized. Ultrasound scan lines are often scanned in a sector around the probe, and in such a case, the scan line density is dense at a short distance from the body surface and conversely at a long distance. Then it becomes coarse.
Although the scanning line density of the ultrasonic wave can be set in various modes, it is often rough in comparison with a video pixel. In such a case, in order to convert the scanning line into a video format scanning line, an interpolation process is performed as schematically shown in FIG. 17, thereby generating a new pixel. Although the image is smoothed by this interpolation processing, the information amount of the image does not increase. For this reason, a situation where the amount of information is smaller than the number of pixels is actually caused.

The present invention has been made in view of the above-mentioned problems of the conventional quantification method, and presents quantitative information indicating how much the tissue property deviates from a normal state with high accuracy. It is a main object of the present invention to provide an ultrasonic diagnostic apparatus and a quantitative analysis method capable of performing the above.

The present invention also provides an ultrasonic diagnostic apparatus and a quantitative analysis system capable of presenting quantitative information indicating how much the tissue shape deviates from a normal state with high accuracy, automatically and easily. It is another purpose to provide the law.

[0028]

In order to achieve the above-mentioned various objects, the ultrasonic diagnostic apparatus of the present invention has, as a basic configuration, an apparatus for obtaining a tomographic image by irradiating an object with an ultrasonic pulse. Analysis area setting means for setting an analysis area in at least a part of the tomographic image; and transmitting the ultrasonic pulse to a subject site corresponding to the analysis area according to a transmission condition for quantitative analysis and transmitting the ultrasonic pulse. And a quantitative analysis transmitting / receiving means for receiving an echo signal generated from the subject site, and a quantitative analysis means for quantitatively analyzing a tissue property based on the echo signal. As a result, quantitative information indicating how much the tissue shape deviates from the normal state can be accurately, automatically and easily presented.

Preferably, the quantitative analysis means includes intensity calculation means for calculating the intensity of the echo signal, and probability density distribution calculation means for calculating a probability density distribution from the data of the intensity of the echo signal.

In this case, preferably, the quantitative analysis means comprises:
Distribution curve display means for displaying the probability density distribution as a curve on a monitor screen is provided. For example, the distribution curve display means is a means for comparing and displaying the probability density distribution curve and the reference probability density distribution curve on the same screen.
Further, for example, the probability density distribution curve serving as the reference may be a probability density distribution curve composed of theoretical values according to a Rayleigh distribution.

As another example, a transfer means for transferring the curve data of the probability density distribution to the outside of the apparatus via a recording medium or a communication means may be provided.

As still another example, the quantitative analysis means includes intensity calculation means for calculating the intensity of the echo signal, probability density distribution calculation means for calculating a probability density distribution from the data of the intensity of the echo signal, Error calculating means for calculating an error between the density distribution and a reference probability density distribution,
Quantification information presenting means for presenting the error as quantification information of the tissue property. For example,
The error calculating means is means for calculating an error between the calculated probability density distribution and the reference probability density distribution as a least square error based on a least square method.

Various configurations can be added to the above-described configurations. For example, it is desirable to have command means for commanding at least one of start and end of quantitative analysis by the quantitative analysis means. The transmission and reception according to the transmission condition may be transmission and reception in which the scanning line density of the ultrasonic pulse is set to be twice or more the scanning line density for an area other than the analysis area.
Further, this transmission / reception may be transmission / reception in which an echo signal on the same scanning line by an ultrasonic pulse is acquired twice or more under different transmission / reception conditions, or the transmission / reception of the ultrasonic pulse may be performed on an analysis area. Transmission and reception performed by parallel simultaneous reception in two or more directions may be performed, and scanning on the same scanning line by an ultrasonic pulse is performed two or more times by a combination of different transmission transducers, and the same echo 2 from the combination of different receiving oscillators for the signal
The transmission and reception may be performed in at least one of the modes of receiving more than once. Further, for example, transmission and reception according to the transmission condition may be transmission and reception in which scanning on the same scanning line by an ultrasonic pulse on the analysis region is performed two or more times while changing the transmission focal point. This transmission / reception may be transmission / reception performed using an ultrasonic pulse including a coded broadband frequency component as the ultrasonic pulse. Further, the transmission and reception according to the transmission condition may be transmission and reception performed using an ultrasonic pulse composed of a chirp signal including a wideband frequency component as the ultrasonic pulse.

Further, as another preferred example, there are monitoring means for monitoring the saturation state of the signal intensity at the time of calculating the intensity of the echo signal, and re-instruction means for instructing requantification analysis when the saturation state occurs. Can be prepared.

Further, preferably, in each of the above-described configurations, a condition setting means for presetting conditions necessary for quantitative analysis can be provided. In this case, the conditions include, for example, the transmission / reception frequency of the ultrasonic pulse, the initial shape of the analysis area, the presence / absence of real-time display of the probability density distribution curve generated by the quantitative analysis, the presence / absence of real-time display of the result generated by the quantitative analysis, Also, at least one of the display position, color, and size of the information can be included. The condition may include a total number of the echo signal samples used for the quantitative analysis. Further, an interface means capable of changing the size and shape of the analysis area by the operator can be provided.

Further, in each of the above-described devices,
It is also a desirable mode to include an exclusion unit that sets an area in which a signal group unnecessary for quantitative analysis of the echo signal is excluded from the analysis area. For example, the elimination unit is a unit that eliminates, as an unnecessary signal group, an echo signal corresponding to a tissue structure extracted by the contour extraction method. Further, the elimination unit is a unit that eliminates an echo signal corresponding to a blood vessel and a blood vessel wall based on blood flow information extracted from an ultrasonic Doppler signal obtained by separately transmitting an ultrasonic signal as an unnecessary signal group. There may be.

Further, in the ultrasonic diagnostic apparatus according to the basic configuration, the quantitative analysis means includes data acquisition means for acquiring data before the echo signal is converted into image data and subjecting the data to quantitative analysis. Can be.

As another preferred example, the quantitative analysis means may include an automatic stop means for automatically stopping transmission and reception in accordance with the transmission conditions when acquiring the total number of samples based on the echo signal. Good.

Further, as another preferred example, means for storing the data of the tomographic image, means for associating the signal intensity data calculated by the intensity calculating means with the spatial position of each pixel of the tomographic image, and an analysis area Means for performing a quantitative analysis by calling the corresponding signal strength data when set.

Further, in the ultrasonic diagnostic apparatus having the above-described basic configuration, an ultrasonic probe in which transducers for transmitting and receiving the ultrasonic pulse are two-dimensionally arranged, and an ultrasonic probe perpendicular to a tomographic plane in the subject. Scanning means that can be changed to the above, wherein the quantitative analysis transmitting / receiving means obtains an echo signal of a tomographic plane corresponding to the analysis area, and obtains an echo signal of another cross section in a direction perpendicular to the tomographic plane. With
The quantitative analysis means may be a means for quantitatively analyzing a tissue property based on the two echo signals.

On the other hand, in the method for quantitatively analyzing tissue properties by ultrasonic waves according to the present invention, a tomographic image is obtained by irradiating an object with an ultrasonic pulse, and an analysis area is set in a part of the tomographic image. And transmitting an ultrasonic pulse to the subject site corresponding to the analysis region according to the transmission conditions for quantitative analysis, and receiving an echo signal generated from the subject site with the transmission,
It is characterized in that a tissue property is quantitatively analyzed based on the echo signal. With this, quantitative information indicating how much the tissue shape deviates from the normal state with high accuracy,
It can be presented automatically and easily.

For example, preferably, the quantitative analysis includes a process of calculating the intensity of the echo signal and a process of calculating a probability density distribution from the data of the intensity of the echo signal. Further, for example, the quantitative analysis may include a process of calculating the intensity of the echo signal and a process of calculating the probability density distribution from the data of the intensity of the echo signal. In addition to this, the quantitative analysis may include a process of calculating an error between the probability density distribution and a reference probability density distribution, and a process of presenting the error as quantification information of the tissue property. Good.

Further, according to another configuration of the ultrasonic diagnostic apparatus of the present invention, in an apparatus for obtaining a tomographic image by irradiating an object with an ultrasonic pulse, an analysis area is set in a part of the tomographic image. The analysis region setting means and the ultrasonic pulse are transmitted to an object region corresponding to the analysis region under conditions for increasing the number of echo signal samples based on the independent event, and generated from the object region with this transmission. And a quantitative analysis transmitting / receiving means for receiving the echo signal to be transmitted and a quantitative analysis means for quantitatively analyzing the tissue property based on the echo signal. For example, the quantitative analysis unit is a unit that obtains an index representing the property of the tissue in the analysis region based on the intensity of the echo signal. As a result, quantitative information indicating how much the tissue shape deviates from the normal state with high accuracy,
It can be presented automatically and easily.

[0044]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) A first embodiment will be described with reference to FIGS.

The ultrasonic diagnostic apparatus according to this embodiment has a transmission / reception system for obtaining a B-mode tomographic image and a CFM (color flow mapping) image of the subject. Among them, the transmission / reception system for obtaining the B-mode tomographic image is a transmission system specialized in quantitative analysis necessary for analyzing the property of the tissue quantitatively and presenting an index of the property state based on the present invention. A system capable of transmitting conditions is provided. Hereinafter, this device will be specifically described.

FIG. 1 schematically shows the entire configuration of the ultrasonic diagnostic layer apparatus according to the first embodiment. The ultrasonic diagnostic apparatus includes an apparatus main body 11, an ultrasonic probe 12 connected to the apparatus main body 11, and an operation panel 13.

The operation panel 13 has a keyboard, a trackball, a mouse, and the like. These operating devices allow the operator to obtain patient information, device conditions,
In addition to being used to input or set an OI (region of interest) and the like, transmission / reception conditions necessary for quantitative analysis of tissue properties according to the present invention, analysis region command information, display mode selection information,
It is used to input a command to start and / or end quantitative analysis.

The ultrasonic probe 12 is a device that transmits and receives ultrasonic signals to and from the subject, and has a piezoelectric vibrator such as a piezoelectric ceramic as an electromechanical reversible conversion element. As a preferred example, a plurality of piezoelectric vibrators are arranged in an array and mounted at the tip of the probe, and a phased array type probe 12 is configured. Accordingly, the probe 12 converts the pulse drive voltage given from the apparatus main body 11 into an ultrasonic pulse signal and transmits the ultrasonic pulse signal in a desired direction within the scan area of the subject, and also converts the ultrasonic echo signal reflected from the subject into an ultrasonic echo signal. The signal is converted into an echo signal having a voltage corresponding to this.

As the diagnostic mode selected in the apparatus main body 11, "normal B mode", "CFM mode", and "quantitative analysis mode (belonging to B mode)" are used.

Specifically, the apparatus main body 11 includes the probe 1
Transmission unit 21 and reception unit 2 connected to
2. an adder 2 placed on the output side of this receiving unit 22
4, a receiver 25, a B-mode DSC (digital scan converter) 26, a data synthesizer 27 (containing a color coding circuit), and a display 27 in this order. An image memory 28 is connected to the DSC 25.

Further, a CFM unit 29 and a CFM mode DSC 30 for color flow mapping are provided in a state where the CFM unit 29 and the DSC 25 are provided side by side.

Further, a signal strength calculator 31 for calculating the strength (amplitude) of the echo signal and a quantitative analyzer 32 for performing a quantitative analysis of the echo signal are connected to the receiver 24 in this order. A storage medium 33 and an interface circuit 34 are connected to the quantitative analyzer 32. Further, the quantitative analyzer 32 can output the analysis result to the data synthesizer 26 as well.

Further, the apparatus main body 11 includes a controller 40 for receiving an operation signal from the operation panel 13,
A data generator 41 that operates in response to an instruction from the controller 40 is provided.

The configuration and operation of each of the above components will be described.

The transmitting unit 21 includes a pulse generator 51,
A transmission delay circuit 52 and a pulsar 53 are provided. The pulse generator 51 has a constant pulse repetition frequency (PRF: pu).
1se repetition frequency)
To generate a rate pulse. This rate pulse is
It is distributed to the number of transmission channels and sent to the transmission delay circuit. The transmission delay circuit 52 is supplied with a timing signal for determining a delay time from the controller 40 for each transmission channel. Thereby, the transmission delay circuit 5
2 assigns a command delay time to the rate pulse for each channel.

The rate pulse provided with the delay time is supplied to the pulser 53 for each transmission channel. This pulsar 5
For example, a circuit having a relatively simple configuration, which generates a rectangular pulse by turning on / off a switching circuit, or an arbitrary waveform generator represented by a linear amplifier, can be used as the component 3. The pulser 53 applies a voltage pulse to each of the piezoelectric vibrators (transmission channels) of the probe 12 at the timing of receiving the rate pulse. As a result, an ultrasonic signal is emitted from the probe 12. Ultrasonic probe 1
The ultrasonic signal transmitted from 2 is focused in a beam shape within the subject, and is set in the scan direction in which the transmission directivity is commanded.

The ultrasonic pulse signal transmitted into the subject is reflected on the discontinuous surface of the acoustic impedance.
The reflected ultrasonic signal includes a component scattered by a scatterer in the tissue. The reflected ultrasound signal is again
2 and is converted into an echo signal of a corresponding voltage amount. This echo signal is taken into the receiving unit 22 from the probe 12 for each receiving channel.

The receiving unit 22 includes a preamplifier 61, an A / D converter 62, and a receiving delay circuit 63 in order from the input side. Preamplifier 61, A / D converter 6
2 and the reception delay circuit 63 each have a built-in circuit for the reception channel, and are formed in a digital type receiver. The delay time of the reception delay circuit 63 is provided from the controller 40 as a signal of a delay time pattern in accordance with a desired reception directivity. Therefore, the echo signal is amplified by the preamplifier 61 for each reception channel,
The digital signal is converted into a digital signal by the A / D converter 62, the delay time is given by the reception delay circuit 63, and the signals are added to each other by the adder 23. By this addition, the reflection component from the direction corresponding to the desired reception directivity is emphasized. By integrating the performances of the transmission directivity and the reception directivity, the overall performance of the transmitted and received ultrasonic beams can be obtained.

As shown in FIG. 1, the output terminal of the adder 23 is connected to the receiver 24 and the CFM unit 29.
The receiver 24 forms a B-mode processing system.

As shown in FIG. 2, the receiver 24 includes an envelope detection circuit 61 for receiving a digital echo signal generated by the addition of the adder 23.
A gain correction circuit 62, an echo filter 62, a signal strength calculator 64, and a logarithmic compressor 65 are provided in this order. The output terminal of the logarithmic compressor 65 reaches the B-mode DSC 25 described above. The output terminal of the echo filter 63 is also connected to another signal strength calculator 31.

As a result, the echo signal is converted to the envelope detection circuit 6
The signal is envelope-detected by 1 and converted into a baseband echo signal. Further, a gain correction circuit 62 performs gain correction for attenuation in the depth direction.

The echo signal adjusted to have a substantially constant gain in the depth direction is subjected to various filterings by an echo filter 63 which is a digital filter.
The echo filter 63 is used as a filter as a so-called digital image optimizer (DIO) that aligns the waveform of an echo signal that has collapsed due to attenuation in the depth direction, or an ultrasonic pulse used when performing a harmonic imaging method. It functions as a high-pass type echo filter that passes only a harmonic component, for example, twice as high as the transmission frequency of the signal.

The echo signal that has been subjected to various filterings by the echo filter 63 is then sent to a signal strength calculator 64, where the signal strength (absolute value) is calculated. The signal intensity data is further logarithmically compressed (logarithmically amplified) by the logarithmic compressor 65, and sent to the DSC 25 as image data in each scanning line direction capable of expressing the signal intensity as luminance.

The image data in the scanning line direction sent to the DSC 25 is subjected to post-processing such as smoothing, and is then scan-converted into B-mode image data of a video format. This B-mode image data is DS
It is sent to C26 in real time.

On the other hand, by the DSC 25, at least one of the image data related to the ultrasonic scan before the scan conversion and the image data of the video format after the scan conversion generated during the scan is stored in the image memory for a plurality of frames, for example. 28. The image data stored in the image memory 28 can be read by an operator after scanning (that is, after real-time diagnosis) and can be reused for display or the like. For example, a plurality of frames of read image data can be reproduced as a moving image. Can be.

The data synthesizer 26 is provided with the CFM image data of the blood flow as required by the well-known operations of the CFM unit 29 and the CFM mode DSC 30. Although not shown, the controller 40
When the transmission unit 21, the reception unit 22, and the CFM unit 29 are instructed to perform the scan in the FM mode, the CFM image data is obtained.

As schematically shown in FIG. 2, in this reception processing system, the echo signal is an RF signal having the largest amount of information as an echo signal in a stage from the output of the probe 12 to the input to the detection circuit 61. The signal having the same information as that of the RF signal from the output of the detection circuit 61 to before input of the signal strength calculator 64, and the amount of information after the output of the signal strength calculator 64 is smaller than that of the RF signal. Takes the form of a video signal with reduced power.

Therefore, in the present embodiment, as shown in FIG. 2, the echo filter 63 is used as a second signal having a signal whose information amount is still equal to that of the RF signal.
The filtered echo data is taken out from the output terminal of, and is supplied to another signal strength calculator 63. The calculator 31 also calculates the signal strength from the echo data having the real part and the imaginary part, similarly to the signal strength calculator 64 described above. However, this calculator 31 calculates the signal intensity required for quantitative analysis of the tissue properties, and its calculation range is instructed by a controller 40 described later as an analysis area. The signal strength in the designated analysis area calculated in this way is recorded in the storage medium 33 such as a magnetic memory.

Since the analysis area is instructed by the controller 40 in the quantitative analysis mode, the latter signal strength calculator 31 also serves as the signal strength calculator 64 described above. You may. In this case,
The controller 40 sends the signal strength calculator 64 to
What is necessary is just to instruct the intensity calculation in the quantitative analysis mode.

When the intensity calculation in the signal intensity calculator 32 is completed, the completion is notified to the quantitative analyzer 32. Upon receiving the notification, the quantitative analyzer 32 reads the signal intensity data in the analysis area stored and held in the recording medium 33, processes the data according to a quantitative analysis algorithm given in advance, and analyzes the data. Perform quantitative analysis on tissue properties in the area.

The result of the quantitative analysis is output as a probability density distribution curve of the echo signal or an error value between the curve and a reference probability density distribution curve, as described later. This output destination is selectively instructed by the controller 40. In the present embodiment, one output destination is the data synthesizer 26 for displaying the image together or alone, and the other output destination is the interface circuit 34 for transferring the image to the outside of the apparatus. Interface circuit 3
Numeral 4 provides the quantitative analysis results to a storage medium outside the apparatus, a diagnostic database, an electronic medical record system, a printer, a separate computer, and the like via the communication network 35.

The program describing the quantitative analysis algorithm used in the quantitative analyzer 32 may be stored in the memory of the analyzer itself, but is stored in the storage medium 33 and updated as needed. It may be. When the calculation result of the signal strength calculator 31 is read one by one into the quantitative analyzer 32, a storage medium 33 provided separately is provided.
Can be configured to be detached from the device.

On the other hand, the data generator 36
Is provided. The generator 36 generates data such as characters and scales for annotation and / or graphic data in response to a command from the controller 40, and supplies the data to the data synthesizer 26. This data includes an analysis area (see FIGS. 5 and 6) specified by the operator on the tomographic image and an area whose shape has been corrected.

As described above, the data synthesizer 26 receives the image data of the B-mode image, the image data of the CFM mode image, the data representing the quantitative analysis results, such as graphs and / or numerical values, And data such as characters and scales and / or graphic data as data assisting the image processing, and synthesizes the image data with an appropriate display mode such as superimposing or arranging with an image, which is instructed by the controller 40.

The final image data thus synthesized is sent to the display 27. In the display 27, the image data is converted into an analog amount by a built-in D / A converter, and is displayed on a screen of a TV monitor or the like as an image of the tissue property of the subject and / or an image including a quantitative analysis result. . In this image, a desired portion and / or data is colored as necessary.

On the other hand, the controller 40 is a computer device having a CPU and a memory, and controls the operation of the entire device according to a procedure programmed in advance. The control operation includes a process for a diagnostic mode, a transmission / reception condition, a display mode, an output destination of a quantitative analysis result, and the like, which are instructed by the operator via the operation panel 13. The control operation includes transmission control (transmission timing, transmission delay, etc.) for the transmission unit 21 and the reception unit 22.
Control (reception delay, etc.) for the data generator 36
Command to generate display data such as character information and scales for
The instruction includes a command to start the calculation for the signal strength calculator 31, a command for an output destination of the analysis result to the quantitative analyzer 32, and a command for a display mode to the data synthesizer 26.

In the configuration described above, the operation panel 13,
The controller 40, the data generator 36, and the data synthesizer 26 form the main part of the analysis area setting means of the present invention,
Probe 12, transmitting unit 21, receiving unit 22,
The adder 23 and the controller 40 form a main part of the transmitting / receiving means for quantitative analysis of the present invention.
Signal strength calculator 31, storage medium 33, and quantitative analyzer 3
2 is a main part of the quantitative analysis means of the present invention.

Next, the operation and effect of this embodiment will be described.

The ultrasonic echo scattered by the tissue or the like in the subject with the transmission of the ultrasonic pulse from the transmission unit 21 is received by the probe 12 and converted into an electric echo signal by the vibrator. This echo signal is
To the receiving unit 22 for each channel. Then, the receiving unit 22 and the adder 23 beam-focus the echo signal for each channel, and form a converged echo signal as described above. This echo signal is supplied to the receiver 24 and the CFM unit 29.

Now, assuming that the diagnosis of the B mode is instructed, the echo signal is transmitted to the receiver 2 forming the B mode processing system.
4 and a B-mode D
The data is post-processed and format-converted by the SC 25 and sent to the data synthesizer 26 as B-mode image data. Necessary annotations and graphic data are further superimposed on the B-mode image data by the data synthesizer 26. In this state, the display 27 is displayed as a B-mode image.
Will be displayed.

From this state, it is assumed that the operator operates the operation buttons on the operation panel 13 to instruct the "quantitative analysis mode". In response, the controller 40 cooperates with the receiver 24, the signal strength calculator 31, and the quantitative analyzer 32 to execute a process according to the flow schematically shown in FIG. This processing will be described in detail below.

(Step S1) First, at the time of quantitative analysis of the tissue properties under the “quantitative analysis mode”, a preset function that allows the operator to set the parameters of the quantitative analysis is exerted via the controller 40 (step S1).
1). This may be immediately before the quantitative analysis is performed, or may be set in advance before starting the overall diagnosis. The parameters of quantitative analysis include the transmission / reception frequency at the time of quantitative analysis, the total number of samples (the more samples, the more accurate the analysis, but the longer the collection time), the shape of the analysis area, and the probability density distribution curve. The presence or absence of real-time screen display, the presence or absence of real-time display of quantitative analysis results, the display position, color, size, and the like of such information can be set.

(Step S2) Next, the analysis area is set at a desired position on the B-mode tomographic image displayed on the display 27 based on the operator's command, and the operation panel 13, the controller 40, and the data generator 36 are operated. Is set via Although the shape of the analysis region RG _ana is predetermined by the preset function as described above, the shape is shown in FIGS. 4 (A) and 4 (B).
As shown in FIG. 7, various types such as a square and an ellipse can be set. The analysis region RG _{a na} is long sides with a trackball or the like of the operation panel 13, by changing the size of such a short side, and is adjustable its shape (Fig. 4 (A), ( Regions RG _{ana1 to} RG in B)
_ana3 ). Further, by selecting “freehand mode” as the operation mode of the analysis area RG _ana ,
As shown in FIG. 4C, it is also possible to set an arbitrary shape by freehand.

In the process of step S2, when setting the analysis region RG _ana , it is important for the operator to take care not to include structures unnecessary for analysis, such as blood vessels and organ boundaries. In the present embodiment, however, as shown in FIG. 5A, even when those unnecessary structures are included in the analysis region RG _ana , the region is reset (corrected) so as to exclude the structures. It has a function (see FIG. 5C).

Specifically, the fact that echo signals reflected from blood vessel or organ boundaries are continuously connected is used. That is, as shown in FIG. 5B, the contour of the structure is extracted using a conventionally known contour extraction method, and the analysis region RG _ana is set so as to exclude the structure (see FIG. 5C). ). This makes it possible to relatively easily set the analysis region RG _ana excluding the structure.

As another exclusion method, there is a method using a well-known Doppler method. Since the present ultrasonic diagnostic apparatus has the imaging function of the CFM mode based on the Doppler method, the scan mode is temporarily switched to the CFM mode to extract the blood vessel portion BV as shown in FIG.
As shown in (C), the blood flow portion can be excluded from the analysis region RG _ana .

(Step S3) Next, a command to start quantitative analysis is made by the operator via the operation panel 13 (step S3). In response, the controller 40
, The transmission / reception state of the quantitative analysis mode is instructed to the transmission unit 21, the reception unit 22, and the receiver 24. Further, the controller 40 issues a command to the signal strength calculator 31 to start the calculation.

(Steps S4 to S7) In response, in steps S4 to S7, control, processing, and calculation in the transmission / reception state in the quantitative analysis mode are executed.

The most important purpose of the quantitative analysis mode is to collect more echo signal samples within a designated analysis area in a shorter time. A point to be noted in this collection is that "collecting a plurality of samples in exactly the same transmission / reception state does not necessarily increase the amount of information, but rather causes a bias in the probability density distribution." That is the fact.
For example, in the case of the above-mentioned dice, even if the event (three, two, five) of three times of rolling the dice is multiplied by 100, it is not necessarily the case that the dice is rolled 300 times. Therefore, in the transmission and reception in the quantitative analysis mode, various different transmission and reception states as described below can be adopted in order to avoid such a bias in the probability density distribution (step S4).

When the information of the transmission delay circuit 52 shown in FIG. 1 is changed, the scanning line density in the analysis area RG _ana becomes more than twice as dense as the conventional one (see FIG. 6). In general, the scanning line density and the frame rate (the number of acquired tomographic images per unit time) are in inverse proportion, but this method generates a locally dense scanning line state only for the analysis region RG _ana. As a result, the decrease in the frame rate can be kept relatively small.

The reception delay circuit 63 is provided with an analysis area RG
_ana only, 2 for the echo signal for one transmitted ultrasonic wave
Multiply more than one pattern delay by time division. Thus, so-called parallel simultaneous reception that obtains reception echoes in two or more directions is adopted.

Further, with respect to the probe 12, even if the scanning lines are in the same direction, the number or the position of the transmitting transducers to be driven and the number or the position of the receiving transducers are changed. As a result, as shown in FIG. 7, separate scattered echo signals (1) and (2) can be collected.

Further, the echo filter (digital filter) 63 of the receiver 24 performs filtering on one echo signal sequence with a plurality of cutoff frequencies and bands. As a result, a sample group including a plurality of different types of signal intensities can be obtained.

Further, similarly, the delay time pattern of the transmission delay circuit 52 is controlled, and the depth of the transmission focus can be changed. However, if the focus is changed too much, the total signal strength will change significantly.
It is desirable to change the focus within a relatively small range, or to correct the total signal strength in advance by normalizing the maximum value of the echo signal.

FIG. 8 shows an example of this normalization. Now, at the first focus, the signal A of FIG.
However, it is assumed that the signal B of FIG. 9B whose maximum amplitude is d2 is obtained at the second focus. At this time, normalization is performed by multiplying the data of the signal B by the value of d1 / d2. FIG. 9A shows another standardization method.
The averages E ₁ and E ₂ of the data sequence of (B), that is,

(Equation 2) In the above, the data of the signal B may be multiplied by E ₁ / E ₂ .

Further, the transmission frequency is also controlled to various values, whereby echo signals in different transmission / reception states are collected. However, even in this case, if the transmission frequency changes too much, the total signal strength will change greatly. Therefore, as described above, the transmission frequency is changed in a relatively small range, or the total signal strength is standardized in advance.

As described above, by changing at least one of the various parameters related to the transmission / reception state, the total number of samples in the analysis region RG _ana with the number of samples of different types of scattered echo signals increased. N can be significantly increased as compared with the conventional method.

When the number of samples N is fixed, the higher the resolution of the echo signal, the greater the amount of information contained therein. From this viewpoint, it is desirable that the transmission / reception frequency be as high as possible and that the pulse period (wave number) be small. However, if the transmission / reception frequency is excessively increased, the effect of living body attenuation also increases, and there is also a problem that S / N deteriorates in a deep part.

In order to secure S / N in wideband transmission, a pulse compression method is employed by using a pulser 53 having an arbitrary waveform generator. This technique is already known in radar technology and the like, and transmits a relatively long coded pulse train and compresses a received signal on a time axis, whereby the resolution can be increased. For long pulse trains,
As a whole, a higher power can be applied as compared with a single pulse having the same amplitude. Further, as another method related to the above-mentioned wideband transmission, a method using a chirp signal whose frequency continuously changes may be used, and the effect of securing an S / N can be similarly obtained.

By scanning in different transmission / reception states, a plurality of sample data are collected (step S5). Thereby, data collection with a large amount of information is performed.

In this data collection, in the present embodiment, a B-mode scan for generating a B-mode tomographic image of the entire field of view is performed at appropriate time intervals under the control of the controller 40. This allows the operator to set the analysis area RG
_Since the position of _ana can be determined from the entire B-mode tomographic image, the analysis region RG _ana is not lost,
It can always be kept in a fixed position.

In this B mode scan, B
Among the echo signals for generating the mode tomographic image, at least the echo signals scattered from the region outside the analysis region RG _ana are not sent to the signal intensity calculation unit 31 for quantitative analysis under the control of the controller 40. So that it is not subjected to quantitative analysis. As a result, the quantitative analysis is performed only on the echo signals scattered from inside the analysis area RG _ana .

The echo signal scattered from the analysis area RG _ana and taken from the receiving system at the echo filter output stage of the receiver 24 is sent to the signal strength calculator 31. The arithmetic unit 31 calculates the signal intensity from the acquired echo signal on each scanning line, and stores the intensity data in the storage medium 33 (step S6).

In general, the number of echo data per unit length for one scanning line is determined by the sampling frequency in the system and is, for example, 1000 data per cm. Now, the analysis area RG _ana
Is assumed to be a square with one side and 1 cm, under the exclusive transmission / reception conditions in the quantitative analysis mode, the transmission scan line density is n in the analysis area, the number of parallel simultaneous receptions is m, and the combination of the positions of the transmission transducers is Ct. If the combination of the positions of the receiving transducers is Cr and the type of the frequency is d, the total number of samples in the analysis area is

## EQU3 ## 1000 × n × m × Ct × Cr × d When the set quantitative analysis parameters include the total number of samples N, the above variables are appropriately adjusted to a combination of variables that provides the number of samples closest to the total number of samples N.

In the processing of intensity calculation and recording in step S6, the signal intensity calculator 31 is configured to also exhibit a function of checking the saturation state of the echo signal. When the digital amount of echo data has reached the maximum value that the system can take, the arithmetic unit 31 automatically detects this and sends the detection information to the controller 40. Thereby, the controller 40 automatically lowers the gain of the preamplifier 61 of the receiving unit 22, and performs exclusive transmission and reception again in the quantitative analysis mode. Since the remeasurement is performed automatically, labor saving of the operation of the operator can be achieved.

(Step S7) The collection of the sample data for quantitative analysis described above is continued until the total number of samples from the analysis area RG _ana reaches N (step S7).

(Steps S8 to S11) Next, when the number of samples reaches N, the controller 40 automatically notifies the relevant unit of the end of the exclusive transmission / reception state based on the quantitative analysis mode. The process returns to the scan (Step S8).

Thereafter, the signal strength calculator 31 notifies the quantitative analyzer 32 of the completion of the strength calculation. In response, the quantitative analyzer 32 reads the signal intensity data in the analysis area RG _ana from the storage medium 33, and performs the quantitative analysis and the error evaluation (step S9).

Specifically, the calculated signal strength data is mapped to a probability density distribution. This mapping is
This is a calculation process in which the range in which the intensity value of the echo signal can be taken is divided into appropriate minute sections, and how many pieces of data corresponding to those sections exist. For example, when signal strength values I _i (i = 1, 2,..., N) of the number of samples N are obtained,
A small displacement of the intensity value is represented by Δx,

## EQU4 _## The number P (x) of I _i satisfying x ≦ I _i ≦ x + Δx is obtained. In addition to this, the calculated signal strength data

Equation 5] (1 / C) was divided by ∫ ₀ ^∞ xP (x) satisfy dx = 1 the computing equation C, and creates data for displaying the probability density distribution curve.

Various techniques can be considered for evaluating the error of the analyzed probability density distribution curve. The most typical method has a least square error. This is calculated using the probability density function Pr (x) of the theoretical Rayleigh distribution, which is a kind of normal distribution.

[6] obtained by ^{_{∫ 0 ∞ (P (x)}} -Pr (x)) by calculating a 2 dx. Here, other methods may be used for the method of evaluating the error, that is, the method of quantitatively expressing the degree of deviation from the Rayleigh distribution. For example, conventionally known Q-
A probability distribution such as a Q probability density plot method or a Weibull distribution may be used. In this embodiment, these evaluation methods are updated as needed by software, stored in the recording medium of FIG. 33, and provided to the user as needed.

(Steps S10A, S10B, S11)
Next, the result of the quantitative measurement of the analysis region RG _ana is displayed. In the display 27, in addition to the curve of the analyzed probability density distribution, the numerical value of the error evaluation result, a quantitative analysis parameter such as the number of samples and the frequency used, or a representative parameter selected from some of the parameters Can be displayed simultaneously (steps S10A, S10B).
The result of the quantitative analysis can be recorded and stored through a printer or a recording medium (not shown) as necessary (step S11).

Further, this (steps S10A, S10
B, S11) (Steps S10A, S10B, S11)
The quantitative measurement result can be transferred to a device outside the device via a data transmission means (or a recording medium) such as the interface circuit 34 and the network 35 as needed under the control of the controller 40.

As described above, according to the ultrasonic diagnostic apparatus of the present embodiment, information indicating the degree of deviation from the case where the tissue property is normal is quantified, and more accurate quantification is performed. An optimal dedicated transmission / reception state has been established. Moreover, the intensity of the echo signal is RF
The calculation is performed using a signal after detection having substantially the same amount of information as the signal and before video signal conversion.

For this reason, the abnormal degree of the tissue property which has been conventionally empirically determined by the doctor is presented as a quantitative distribution curve or an evaluation value, so that a more accurate and prompt diagnosis can be made.

Furthermore, it is possible to achieve a unique effect not found in the conventional evaluation method described in the above-mentioned paper.

First, a sample for obtaining a probability density distribution is not one that is visually observed and selected from a tomographic image recorded on a video tape or the like as in the prior art. Can be collected in a short time, and a more accurate probability density distribution is required.

Second, the signal strength in this embodiment is:
Instead of using a video image that has already become a luminance image as in the related art, the calculation is performed using a signal having the same information amount as an RF signal. That is, according to the present embodiment, a signal that has undergone a video image generation process, called a post process such as smoothing, a signal that is stored once in a video device and for which linear characteristics are not guaranteed, according to the present embodiment,
Further, a signal whose intensity may be saturated is not used for the intensity calculation. Therefore, more accurate signal strength data can be provided for quantitative analysis.

Third, it is possible to easily set an analysis area so as not to include a high-brightness signal of a blood vessel wall or an organ boundary, and to collect more samples. This enables highly accurate and reliable quantitative analysis.

Further, from the viewpoint of usability, there is an effect that the analysis region as the region of interest can be manually and simply set, and unnecessary structures can be automatically eliminated.

The way of inputting an echo signal to the signal strength calculator 31 for quantitative analysis is not limited to the mode described in the above-described embodiment. The input method shown in FIGS. 9 to 11 may be adopted.

According to the input method shown in FIG.
4 (the echo filter 6).
3) is input to the signal strength calculator 31. Since this input signal has the same amount of information as the RF signal, as described with reference to FIG. 2, a highly accurate signal strength can be calculated.

According to the input system shown in FIG. 10, the echo signal as the RF signal generated by the adder 23 is directly input to the signal strength calculator 31 via the gain correction circuit 81. . As a result, it is possible to calculate the signal strength reflecting the information amount of the RF signal as it is.

Further, in the input system shown in FIG. 11, in the quantitative analysis mode, the existing signal strength calculator 64 in the receiver 24 is also used as a command of the controller 40 to convert the echo signal in the analysis area. After calculating the intensity and converting it into a video signal, the input is input to the quantitative analyzer 32. The echo signal converted into a video signal has a reduced amount of information as compared with the signal up to the previous stage, but is input without performing post processing such as smoothing by the DSC 25, so that compared with the conventional method using a video signal, High-precision quantitative analysis can still be performed.

(Second Embodiment) An ultrasonic diagnostic apparatus according to a second embodiment of the present invention will be described with reference to FIG.

This ultrasonic diagnostic apparatus has the same functions as those of the above-described ultrasonic diagnostic apparatus of the first embodiment, but differs from the above-described ultrasonic diagnostic apparatus in the quantitative analysis mode performed in the quantitative analysis mode as shown in FIG. In the parameter settings. Other configurations are the same as those of the first embodiment.

More specifically, FIG. 12 shows a case where the controller 40 responds when the operator instructs the “quantitative analysis mode” by operating the operation buttons or the like on the operation panel 13 and the receiver 24, the signal strength. The outline of the processing flow executed in cooperation with the arithmetic unit 31 and the quantitative analyzer 32 is shown.

In this processing flow, step S21
In, the quantitative analysis parameters are set. This setting is similar to that of step 1 in FIG. 3 described above, but the total number of samples N is not set. Steps S22 to S22
26 is a process similar to steps S2 to S6 in FIG.
Further, step S27 has the same processing contents as step S9 in FIG. 3, and steps S28A, S28B, S29, and S30 have the same processing contents as steps S10A, S10B to S11 in FIG. However, the processing of step S29 is added in this embodiment.

For this reason, the quantitative analysis is started without setting the total number of samples N, and this quantitative analysis is continued while switching the exclusive transmission / reception state until the operator presses the end button on the operation panel 13 (step S2
9).

As a result, in addition to the operation and effect obtained in the first embodiment, there is no limit to the number of samples.
Over time, a more accurate probability density distribution is obtained. Theoretically, if the number of different combinations of transmission / reception conditions is N, increasing the number of samples to 2N and 3N only reproduces the same conditions, so that the amount of information on tissue properties does not increase. However, in this case, the operator
When the scan cross section is changed by moving 2 by a very small distance, it is not necessary to retry quantitative analysis from the parameter setting, which is a convenient and effective usage. If the probe is moved too much, unnecessary structures may be newly included in the scan cross section. Therefore, it is preferable to keep the probe at a small distance.

Even during the scan in the quantitative analysis mode, the controller 40 is operated in the same manner as in the first embodiment.
Performs a normal B-mode scan at regular intervals. Thus, the tomographic image for setting the analysis area is updated and displayed periodically, so that the operator can continue to observe the desired cross section and reliably determine the position of the analysis area and the like.

(Third Embodiment) An ultrasonic diagnostic apparatus according to a third embodiment of the present invention will be described with reference to FIG.

This ultrasonic diagnostic apparatus has the same function as the ultrasonic diagnostic apparatus of the first embodiment described above, but the image stored in the image memory 28 in non-real time, that is, after scanning (diagnosis). It is characterized in that quantitative analysis is performed as post-processing using data.

Specifically, as in the above-described embodiments, the operator specifies an analysis area in advance and acquires a tomographic image. The image of this tomographic image is recorded in the image memory 28. In parallel with this, the intensity of the echo signal from the analysis area is calculated by the signal strength calculator 31, and the data is stored in the storage medium 33.

Thereafter, the operator presses, for example, a freeze button on the operation panel 13 to stop the B-mode scan. Next, the image data stored in the image memory 28 is reproduced, and the display 27 displays a tomographic image immediately before the stop of scanning. This reproduced and displayed image is a normal B-mode image, and does not reflect information on dedicated transmission and reception performed for quantitative analysis. The signal strength data relating to the dedicated transmission / reception is stored in the storage medium 33.

In this embodiment, the controller 40 associates the spatial position of each pixel of the tomographic image called out from the image memory 28 after scanning with the corresponding signal intensity data stored in the storage medium 33. Can be Therefore, the operator only has to specify an appropriate frame for the image data in the image memory 28 and an analysis area (scanning line number and depth range) in the frame. As a result, the quantitative analysis unit 32 reads the signal intensity data group corresponding to the analysis area from the storage medium 33, and instantaneously obtains and displays analysis results such as a probability density distribution curve and an error value.

As a result, the operator can easily change the analysis area. As long as the change is made within a range smaller than the analysis area specified in advance, it is possible to retry a number of times using the already calculated signal strength data. As a result, it is possible to correct the area by avoiding unnecessary structural parts by detailed observation and positively improve the analysis accuracy.

Needless to say, if the analysis area set in advance is made sufficiently large, the margin for changing the analysis area after scanning is increased. From this point of view, without setting the analysis area in advance,
An analysis area may be set in the image read from the image memory 28, and then, the signal strength data corresponding to the area may be read from the storage medium 33 and analyzed.

(Fourth Embodiment) An ultrasonic diagnostic apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS.

In this embodiment, a two-dimensional probe 12A schematically shown in FIG. 13 is used as an ultrasonic probe. In the probe 12A, ultrasonic transducers are two-dimensionally arranged on the ultrasonic radiation surface. In response to this, by giving the transmission unit 21 and the reception unit 22 an appropriate transmission delay time pattern and reception delay time pattern,
The beam can be deflected not only on the cross section but also in a direction perpendicular to the cross section, as shown in FIG.
Using this, as an exclusive transmission / reception performed in the quantitative analysis mode, a sample based on an echo signal when the ultrasonic beam is shifted by a small distance in a direction perpendicular to the cross section is also collected.

As a result, the degree of freedom to increase the number of independent event samples is increased, and the accuracy of analysis of the probability density distribution can be further improved.

The embodiments described above are not limited to the mode in which the tissue properties of the liver parenchyma are targeted, and the tissue properties of the heart, kidney, spleen and the like may be quantitatively analyzed.

The embodiments described above are merely examples, and are not intended to limit the scope of the present invention. The scope of the present invention is determined based on the description of the claims, and various embodiments can be carried out without departing from the gist of the present invention.

[0144]

As described above, according to the ultrasonic diagnostic apparatus and the method for quantitatively analyzing the tissue characteristics using ultrasonic waves according to the present invention, the probability of the intensity of the echo signal, which has been theoretically proposed, has been conventionally proposed. In a diagnosis based on a method of quantifying an abnormality of a tissue from a density distribution, quantitative information representing the abnormality can be accurately, automatically, and simply presented.

In particular, the number of samples due to independent events is greatly increased by dedicated transmission / reception specialized for quantitative analysis, and accurate quantitative analysis can be performed. Further, an operator can easily perform operations such as setting of an analysis area, and can provide an analysis system with good operability.

In addition, since the operator and the subject can perform the quantitative analysis of the present invention without special preparation, the body fat percentage measurement and the blood pressure measurement can be performed in a normal diagnosis or screening test. Like the above, it can be easily used as one of the medical examination items.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating how to take an input signal of a signal strength calculator for quantitative analysis according to the first embodiment.

FIG. 3 is a flowchart illustrating a schematic process of quantitative analysis according to the first embodiment.

FIG. 4 is a view for explaining a method of setting an analysis area.

FIG. 5 is an explanatory diagram for setting an area excluding a structure from an analysis area.

FIG. 6 is a view for explaining one (dedicated transmission) of a dedicated transmission / reception state in the quantitative analysis mode.

FIG. 7 is a view for explaining another dedicated transmission / reception state (transmission method) in the quantitative analysis mode.

FIG. 8 is a view for explaining signal normalization in a quantitative analysis mode.

FIG. 9 is a block diagram illustrating how to take an input signal of a signal strength calculator for quantitative analysis according to a modification.

FIG. 10 is a block diagram illustrating how to take an input signal of a signal strength calculator for quantitative analysis according to another modification.

FIG. 11 is a block diagram illustrating how to take an input signal of a signal strength calculator for quantitative analysis according to another modification.

FIG. 12 is a block diagram illustrating how to take an input signal of a signal strength calculator for quantitative analysis according to the second embodiment.

FIG. 13 is a schematic diagram of a two-dimensional probe according to a fourth embodiment.

FIG. 14 is a diagram illustrating the operation of a two-dimensional probe.

FIG. 15 is a view for explaining a speckle pattern as a tissue property in a B-mode tomographic image of a normal liver and an abnormal (cirrhotic) liver.

FIG. 16 is a view for explaining a luminance probability density distribution of B-mode tomographic images of a normal liver and an abnormal (cirrhosis) liver.

FIG. 17 is a view for explaining the positional relationship between sample data on an ultrasonic scanning line and pixels in a video format.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body 12 Ultrasonic probe 13 Operation panel 21 Transmission unit 22 Receiving unit 23 Adder 24 Receiver 25 B-mode DSC 26 Data synthesizer 27 Display 28 Image memory 29 CFM unit 30 CFM mode DSC 31 Signal intensity calculator 32 Quantitative analysis Device 33 storage medium 34 interface circuit 35 network 36 data generator 40 controller

Claims (33)

[Claims] 1. An ultrasonic diagnostic apparatus for obtaining a tomographic image by irradiating an object with an ultrasonic pulse, comprising: an analysis region setting unit configured to set an analysis region in at least a part of the tomographic image; A quantitative analysis transmitting / receiving means for transmitting the ultrasonic pulse to a corresponding subject site in accordance with a transmission condition for quantitative analysis and receiving an echo signal generated from the subject site along with the transmission, based on the echo signal An ultrasonic diagnostic apparatus comprising: quantitative analysis means for quantitatively analyzing tissue properties. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the quantitative analysis unit calculates an intensity of the echo signal, and a probability of calculating a probability density distribution from data of the intensity of the echo signal. An ultrasonic diagnostic apparatus comprising: a density distribution calculating unit. 3. The ultrasonic diagnostic apparatus according to claim 2, wherein said quantitative analysis means includes distribution curve display means for displaying said probability density distribution as a curve on a monitor screen. . 4. The ultrasonic diagnostic apparatus according to claim 3, wherein the distribution curve display means displays the probability density distribution curve and a reference probability density distribution curve by comparing them on the same screen. An ultrasonic diagnostic apparatus, comprising: 5. The ultrasonic diagnostic apparatus according to claim 4, wherein the probability density distribution curve serving as a reference is a probability density distribution curve composed of theoretical values according to a Rayleigh distribution. 6. The ultrasonic diagnostic apparatus according to claim 2, further comprising a transfer unit that transfers the curve data of the probability density distribution to outside the apparatus via a recording medium or a communication unit. apparatus. 7. The ultrasonic diagnostic apparatus according to claim 1, wherein the quantitative analysis unit calculates an intensity of the echo signal, and a probability of calculating a probability density distribution from the data of the intensity of the echo signal. Density distribution calculating means, error calculating means for calculating an error between the probability density distribution and the reference probability density distribution, and quantification information presenting means for presenting the error as quantification information of the tissue properties, An ultrasonic diagnostic apparatus comprising: 8. The ultrasonic diagnostic apparatus according to claim 7, wherein the error calculating means calculates an error between the calculated probability density distribution and the reference probability density distribution based on a least square method. An ultrasonic diagnostic apparatus characterized in that it is means for calculating as. 9. The ultrasonic diagnostic apparatus according to claim 1, further comprising command means for commanding at least one of start and end of quantitative analysis by said quantitative analysis means. Ultrasound diagnostic equipment. 10. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission / reception according to the transmission condition includes the step of determining a scanning line density of the ultrasonic pulse with respect to a region other than the analysis region. An ultrasonic diagnostic apparatus characterized in that transmission and reception are set to be twice or more. 11. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission and reception according to the transmission condition are performed by changing the echo signals on the same scanning line by the ultrasonic pulse to different transmission and reception conditions. An ultrasonic diagnostic apparatus characterized in that the transmission and reception are performed at least twice. 12. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission and reception according to the transmission condition are performed in two or more directions on the analysis area in parallel with the transmission of the ultrasonic pulse. An ultrasonic diagnostic apparatus characterized in that transmission and reception are performed by reception. 13. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission and reception according to the transmission conditions are performed by combining scans on substantially the same scan line by the ultrasonic pulse with different transmission transducers. An ultrasonic diagnostic apparatus characterized in that transmission / reception is performed at least one of a mode in which the same echo signal is received twice or more from a combination of different receiving transducers for the same echo signal. 14. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission and reception in accordance with the transmission conditions include: scanning on the same scanning line by the ultrasonic pulse on the analysis area; An ultrasonic diagnostic apparatus characterized in that transmission and reception are performed two or more times while being changed. 15. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission / reception according to the transmission condition is performed using an ultrasonic pulse including a coded wideband frequency component as the ultrasonic pulse. An ultrasonic diagnostic apparatus characterized by performing transmission and reception. 16. The ultrasonic diagnostic apparatus according to claim 1, wherein the transmission / reception according to the transmission condition is performed using an ultrasonic pulse including a chirp signal including a broadband frequency component as the ultrasonic pulse. An ultrasonic diagnostic apparatus characterized by performing transmission and reception. 17. The ultrasonic diagnostic apparatus according to claim 2, wherein a monitoring unit that monitors a saturation state of the signal intensity at the time of calculating the intensity of the echo signal, and performs a requantitative analysis when the saturation state occurs. An ultrasonic diagnostic apparatus comprising: a re-instruction unit for issuing an instruction. 18. The ultrasonic diagnostic apparatus according to claim 1, further comprising: condition setting means for setting conditions necessary for said quantitative analysis in advance. Diagnostic device. 19. The ultrasonic diagnostic apparatus according to claim 18, wherein the condition set by the condition setting means includes a transmission / reception frequency of the ultrasonic pulse, an initial shape of the analysis area, and a probability generated by the quantitative analysis. The presence or absence of real-time display of the density distribution curve, the presence or absence of real-time display of the result generated by the quantitative analysis, and the display position, color, and size of these pieces of information are included. Ultrasound diagnostic equipment. 20. The ultrasonic diagnostic apparatus according to claim 18, wherein the condition set by the condition setting means includes a total number of samples of the echo signal used for the quantitative analysis. apparatus. 21. The ultrasonic diagnostic apparatus according to claim 18, further comprising an interface unit that allows an operator to change a size and a shape of the analysis area. 22. The ultrasonic diagnostic apparatus according to claim 1, wherein a signal group unnecessary for the quantitative analysis among the echo signals is excluded from the analysis region. An ultrasonic diagnostic apparatus comprising means. 23. The ultrasonic diagnostic apparatus according to claim 22, wherein the elimination unit is a unit that eliminates, as the unnecessary signal group, an echo signal corresponding to a tissue structure extracted by a contour extraction method. An ultrasonic diagnostic apparatus characterized by the following. 24. The ultrasonic diagnostic apparatus according to claim 22, wherein the elimination unit adds, as the unnecessary signal group, blood flow information extracted from an ultrasonic Doppler signal obtained by separately transmitting an ultrasonic signal. An ultrasonic diagnostic apparatus, which is means for eliminating an echo signal corresponding to a blood vessel and a blood vessel wall based on the blood vessel. 25. The ultrasonic diagnostic apparatus according to claim 1, wherein the quantitative analysis unit captures data before the echo signal is converted into image data, and processes the data for the quantitative analysis. An ultrasonic diagnostic apparatus comprising: 26. The ultrasonic diagnostic apparatus according to claim 20, wherein said quantitative analysis means automatically stops transmission / reception according to said transmission condition when acquiring said total number of samples based on said echo signal. An ultrasonic diagnostic apparatus comprising means. 27. The ultrasonic diagnostic apparatus according to claim 2, wherein the means for storing the data of the tomographic image, the signal intensity data calculated by the intensity calculating means are associated with the spatial position of each pixel of the tomographic image. An ultrasonic diagnostic apparatus comprising: means for performing quantitative analysis by calling up corresponding signal strength data when the analysis area is set. 28. The ultrasonic diagnostic apparatus according to claim 1, wherein an ultrasonic probe in which transducers for transmitting and receiving the ultrasonic pulse are two-dimensionally arranged, and a direction perpendicular to a tomographic plane in the subject. Scan means that can be changed to, the quantitative analysis transmitting and receiving means, means for acquiring an echo signal of the tomographic plane corresponding to the analysis area, and an echo signal of another cross section in a direction perpendicular to the tomographic plane An ultrasonic diagnostic apparatus, comprising: an acquiring unit, wherein the quantitative analysis unit is a unit that quantitatively analyzes a tissue property based on the two echo signals. 29. A tomographic image is obtained by irradiating the subject with an ultrasonic pulse, and an analysis region is set in a part of the tomographic image. Ultrasound tissue characterized in that a pulse is transmitted in accordance with a transmission condition for quantitative analysis, and an echo signal generated from the subject site is received with the transmission, and a tissue property is quantitatively analyzed based on the echo signal. Method for quantitative analysis of properties. 30. The quantitative analysis method according to claim 29, wherein the quantitative analysis includes a process of calculating the intensity of the echo signal, and a process of calculating a probability density distribution from data of the intensity of the echo signal. A method for quantitative analysis of tissue properties by ultrasonic waves, characterized in that: 31. The quantitative analysis method according to claim 29, wherein, in the quantitative analysis, a process of calculating the intensity of the echo signal, a process of calculating a probability density distribution from data of the intensity of the echo signal, A process of calculating an error between a density distribution and a reference probability density distribution, and a process of presenting the error as quantification information of the tissue property, wherein a quantitative analysis of the tissue property using ultrasound is performed. Method. 32. An ultrasonic diagnostic apparatus for obtaining a tomographic image by irradiating an object with an ultrasonic pulse, comprising: an analysis area setting unit configured to set an analysis area in a part of the tomographic image; The ultrasonic pulse is transmitted under the condition of increasing the number of samples of the echo signal based on the independent event to the subject part to be subjected to the quantitative analysis for receiving the echo signal generated from the subject part with the transmission. An ultrasonic diagnostic apparatus comprising: a transmitting / receiving unit; and a quantitative analysis unit for quantitatively analyzing a tissue property based on the echo signal. 33. The ultrasonic diagnostic apparatus according to claim 32, wherein said quantitative analysis means is means for obtaining an index representing a property of a tissue in said analysis area based on an intensity of said echo signal. Ultrasound diagnostic equipment.