JP4660230B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus capable of presenting, as diagnostic information, a fine blood flow circulation at a capillary level and a fine structure of blood vessel blood flow faster than the capillary blood vessel in a contrast echo method performed using an ultrasonic contrast agent. .

  Ultrasound diagnosis is a simple operation by simply touching the ultrasound probe from the body surface, and heart beats and fetal movements can be obtained in real time. Compared with diagnostic equipment such as CT and MRI, the scale of the system is small, and the inspection can be easily performed while moving to the bedside.

  Ultrasound diagnostic devices vary depending on the types of functions they have, but small ones that can be carried with one hand have also been developed and are not affected by exposure, such as X-rays. It can also be used in home medical care.

  In recent years, intravenous administration-type ultrasound contrast agents have been commercialized, and contrast echoes have been performed. In contrast echo, an ultrasound contrast agent is injected from a vein to enhance a blood flow signal, and blood flow dynamics are evaluated by examination of the heart or liver. In many contrast agents, microbubbles function as a reflection source. Due to the nature of the delicate substrate, bubbles, even if ultrasonic transmission is performed at a normal diagnostic level, the bubbles are broken by the mechanical action, and the signal intensity from the scan section is reduced.

  Therefore, in order to observe the dynamic state of reflux in real time, it is necessary to reduce the collapse of bubbles due to scanning, such as imaging by ultrasonic transmission with low sound pressure. Further, such imaging by ultrasonic transmission with a low sound pressure reduces the signal / noise ratio (hereinafter referred to as “S / N ratio”), and thus various signal processing methods for compensating for it. Has also been devised.

  Furthermore, taking advantage of the feature that bubbles collapse, the following methods have been devised. That is, (a) observe the dynamics of bubbles filling the scan surface under low sound pressure irradiation, (b) switch the irradiation sound pressure to high sound pressure, and remove bubbles in the scan section (strictly in the irradiation volume). (C) This is a method of observing the state of bubbles that flow into the scan section by switching the irradiation sound pressure to a low sound pressure again. This method is called a replenishment method (for example, refer to Patent Document 1).

  Also, a method has been devised for observing the state of bubbles flowing into the scan section by the “maximum value holding method”. For example, a thick blood vessel into which an abundant contrast medium flows as shown in FIG. 10 can grasp the blood vessel structure without any special effort, but the contrast medium as shown in FIG. In the case of a blood vessel, even if one ultrasonic image at a certain moment is viewed, only sparse bubbles exist and the blood vessel structure cannot be grasped. However, if a plurality of ultrasonic images are superimposed and displayed using the “maximum value holding method”, bubbles existing in each image are linked together to construct a continuous blood vessel structure.

  However, when observation is performed for a long time by the “maximum value holding method”, the capillaries in the tissue are filled with the contrast agent, and the entire tissue becomes white as shown in FIG. 12, so that the blood vessel structure cannot be grasped. .

  Therefore, in recent years, an image method called “Micro Flow Imaging (hereinafter referred to as“ MFI ”)” which combines the recirculation method and the maximum value holding method has been devised (see, for example, Patent Document 2). Used in clinical ultrasonography (Toshiba Medical Systems Co., Ltd. Ultrasound Diagnostic Equipment SSA-770A).

  According to the MFI method, when the tissue is filled with the contrast agent, the bubbles in the scan section are collapsed by high sound pressure irradiation, so that the bubbles flowing into the scan section can be repeatedly depicted as shown in FIG. It is possible to accurately grasp the target blood vessel structure.

However, the MFI method still has problems to be solved. One of them is holding the cross section during image acquisition. In the maximum value holding operation, it is assumed that each frame scans the same cross section. If the scan section moves, the result of blood vessel reconstruction will be blurred. In order to maintain the same scan cross section, it is necessary for the operator not to move the ultrasonic probe at all for several seconds, which requires a relatively high level of skill compared to conventional diagnosis. Moreover, since the patient who is the subject must stop breathing and maintain his body position, the burden of fatigue and the like is relatively high.
Japanese Patent Laid-Open No. 11-155858 JP 2004-321688 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic diagnostic apparatus capable of suppressing blurring of an ultrasonic image caused by movement of a scan section. .

  In order to solve the problems and achieve the object, the ultrasonic diagnostic apparatus of the present invention is configured as follows.

(1) In an ultrasonic diagnostic apparatus that scans a predetermined portion of a subject to which a contrast medium bubble has been administered with an ultrasonic wave to acquire an ultrasonic image, the ultrasonic wave is transmitted to the subject, and an echo from the ultrasonic wave Based on an ultrasonic probe that receives a signal, a transmission unit that performs ultrasonic transmission via the ultrasonic probe, and an echo signal obtained by the ultrasonic transmission, a plurality of frames for imaging a tissue mainly. Of the first image information and the first image information generated by the generating means, the generating means for generating the second image information for a plurality of frames mainly for visualizing blood flow, and the i-1th frame And generating means for generating position correction information of the i-th frame with respect to the i-1th frame from the correlation value between the i-th frame and the position correction information generated by the generating means. Correction means for correcting the position of the i-th frame of the second image information generated by the display, and display means for displaying the ultrasonic image based on the i-th frame of the second image information whose position has been corrected by the correction means It comprises.

(2) In an ultrasonic diagnostic apparatus that scans a predetermined part of a subject to which a contrast agent bubble has been administered with an ultrasonic wave to acquire an ultrasonic image, the ultrasonic wave is transmitted to the subject, and an echo from the ultrasonic wave Based on an ultrasonic probe that receives a signal, a transmission unit that performs ultrasonic transmission via the ultrasonic probe, and an echo signal obtained by the ultrasonic transmission, a plurality of frames for imaging a tissue mainly. Generating the first image information and the second image information for a plurality of frames mainly for visualizing blood flow, and the first and second image information generated by the generating unit, Combining means for generating third image information for a plurality of frames including a part of the first image information and a part of the second image information; and a third image information generated by the combining means. included in the (i-1) th frame Creation means for creating position correction information of the i-th frame with respect to the i-1th frame from a correlation value between the image information of the i-th frame and the first image information included in the i-th frame of the third image information; , Based on the position correction information created by the creation means, a correction means for correcting the position of the i-th frame of the third image information, and the i-th frame of the third image information corrected by the correction means. And a display means for displaying the ultrasonic image.

(3) In the ultrasonic diagnostic apparatus described in (1) to (2), the generation unit may generate the first image information and the second image from the same echo signal acquired by the ultrasonic transmission. And image information.

(4) In the ultrasonic diagnostic apparatus described in (1) or (2), the generation unit may generate the first image information and the second image from different echo signals obtained by the ultrasonic transmission. And information.

(5) In the ultrasonic diagnostic apparatus described in (1) to (4), the generation unit performs a luminance value holding calculation based on second image information for a plurality of frames whose positions are corrected by the correction unit. By sequentially executing, luminance value holding image information is generated.

(6) In the ultrasonic diagnostic apparatus described in (5), the luminance value holding calculation is performed by echoing a spatially corresponding position in the second image information for a plurality of frames whose position is corrected by the correction unit. This is a maximum value holding operation for selecting the maximum value from the signal and generating the luminance value holding image information.

(7) In the ultrasonic diagnostic apparatus described in (5) to (6), the display unit displays the luminance value holding image information as the ultrasonic image.

(8) In the ultrasonic diagnostic apparatus described in (1), the generation unit performs frequency analysis based on an echo signal acquired by the ultrasonic transmission, and visualizes the blood flow velocity. The correction means corrects the position of the i-th frame of the second image information generated by the generation means based on the position correction information generated by the generation means, and the display means The i-th frame of the second image information whose position is corrected by the correcting means is displayed as the ultrasonic image.

(9) In the ultrasonic diagnostic apparatus according to any one of (5) to (7), the transmission means transmits a first supersonic wave by a first sound pressure that breaks the contrast agent bubble via the ultrasonic probe. And a plurality of second ultrasonic scans using a second sound pressure for imaging a blood flow and a sound pressure that does not destroy the contrast agent bubble, Generates second image information for the plurality of frames based on echo signals obtained by the plurality of second ultrasonic scans.

(10) In the ultrasonic diagnostic apparatus described in (9), when the first ultrasonic scan is executed, the generation unit initializes the luminance value holding calculation, and performs the next stage multiple times. The luminance value holding image information is generated by sequentially executing the luminance value holding calculation based on the second image information for a plurality of frames, the position of which is corrected by the correction unit, obtained by the second ultrasonic scan. .

(11) In the ultrasonic diagnostic apparatus described in (10), a setting for setting a reference frame for starting the luminance value holding calculation from second image information for a plurality of frames generated by the generation unit Means are further provided.

  ADVANTAGE OF THE INVENTION According to this invention, the blurring of the ultrasonic image resulting from the motion of a scanning cross section can be suppressed.

  Hereinafter, the first to fourth embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
[Configuration of Ultrasonic Diagnostic Apparatus 10]
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of an ultrasonic diagnostic apparatus 10 according to the first embodiment of the present invention. As shown in FIG. 1, the ultrasonic diagnostic apparatus 10 includes an ultrasonic probe 12, an input device 13, a monitor 14, a transmission / reception unit 21 (transmission means), a B-mode processing unit 22, a Doppler processing unit 23, and an image generation circuit 24. (Generating means), an image memory 25, a control processor 26, a software storage unit 27, an internal storage device 28, and an interface 29 are provided. The transmission / reception unit 21 or the like built in the apparatus main body 11 may be configured by hardware such as an integrated circuit, but may be a software program modularized in software. Hereinafter, individual components will be described.

  The ultrasonic probe 12 generates ultrasonic waves based on a drive signal from the transmission / reception unit 21, converts a reflected wave from the subject P into an electric signal, a matching layer provided on the piezoelectric vibrator, A backing material or the like for preventing the propagation of ultrasonic waves from the piezoelectric vibrator to the rear is provided. When ultrasonic waves are transmitted from the ultrasonic probe 12 to the subject P, the transmitted ultrasonic waves are successively reflected by the discontinuous surface of the acoustic impedance of the body tissue and received by the ultrasonic probe 12 as an echo signal. The amplitude of this echo signal depends on the difference in acoustic impedance at the discontinuous surface that is to be reflected. Further, an echo when the transmitted ultrasonic pulse is reflected by a surface such as a blood flow or a heart wall is subjected to a frequency shift due to the Doppler effect depending on the velocity component of the moving body in the ultrasonic transmission direction.

  The input device 13 is connected to the device main body 11, and includes a trackball 13 a and various switches for taking various instructions, conditions, region of interest (ROI) setting instructions, various image quality condition setting instructions, etc. from the operator into the device main body 11. 13b (setting means), buttons, a mouse, a keyboard, and the like. As an instruction from the operator, there is a setting of a reference frame for starting a maximum value holding calculation described later.

  The monitor 14 displays in-vivo morphological information and blood flow information as an image based on the video signal from the image generation circuit 24.

  The transmission / reception unit 21 includes a pulser circuit, a delay circuit, a trigger generation circuit, and the like (not shown). The pulsar circuit repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency fr [Hz] (period is 1 / fr [sec]). The delay circuit gives the delay time necessary for converging the ultrasonic wave into a beam for each channel and determining the transmission directivity for each rate pulse. The trigger generation circuit applies a drive pulse to the ultrasonic probe 12 at a timing based on the rate pulse.

  Note that the transmission / reception unit 21 has a function capable of instantaneously changing a transmission frequency, a transmission drive voltage, and the like in order to execute a scan sequence to be described later in accordance with an instruction from the control processor 26. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching the value or a mechanism for electrically switching a plurality of power supply units.

  Furthermore, the transmission / reception unit 21 includes an amplifier circuit, an A / D converter, an adder, and the like (not shown). The amplifier circuit amplifies the echo signal captured via the ultrasonic probe 12 for each channel. The A / D converter provides a delay time necessary for determining the reception directivity for the amplified echo signal. The adder adds echo signals given delay times. By this addition, the reflection component from the direction corresponding to the reception directivity of the echo signal is emphasized, and a comprehensive beam for ultrasonic transmission / reception is formed by the reception directivity and the transmission directivity.

  The B-mode processing unit 22 receives the echo signal from the transmission / reception unit 21, performs logarithmic amplification, normal detection processing, and the like, and generates data in which the signal intensity is expressed by brightness. This data is sent as a received signal to the image generation circuit 24, and after various processing, is displayed on the monitor 14 as a B-mode image in which the intensity of the reflected wave is expressed by luminance. The B-mode processing unit 22 has a frequency filter (not shown) that separates the echo signal from the transmission / reception unit 21 for each frequency.

  The Doppler processing unit 23 receives an echo signal from the transmission / reception unit 21, analyzes the velocity information from the echo signal, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and average velocity, dispersion, power, etc. Blood flow information is obtained for multiple points. The obtained blood flow information is sent to the image generation circuit 24 as a reception signal, and after various processing, is displayed in color on the monitor 14 as an average velocity image, a dispersion image, a power image, and a combination image thereof.

  The image generation circuit 24, together with the B-mode processing unit 22 and the Doppler processing unit 23, constitutes an image information generation unit 20 (generation unit) that generates various image data based on the echo signal. Further, the image generation circuit 24 is equipped with a storage memory for storing image data, and for example, an operator can call up image data recorded during examination after diagnosis. The image generation circuit 24 is an important point of the present invention, and details thereof will be described later.

  The image memory 25 includes a storage memory that stores image data received from the image generation circuit 24. This image data can be called by an operator after diagnosis, for example, and can be reproduced as a still image or as a moving image using a plurality of frames. Further, the image memory 25 outputs an output signal immediately after the transmission / reception unit 21 (referred to as a radio frequency (RF) signal), an image luminance signal after passing through the transmission / reception unit 21, other raw data, image data acquired via a network, and the like. Is stored as necessary.

  The internal storage device 28 stores a control program for executing a scan sequence, image generation, and display processing, which will be described later, diagnostic information (ID, doctor's findings, etc.), diagnostic protocol, transmission / reception conditions, and other data groups. Yes. Data in the internal storage device 28 can also be transferred to an external peripheral device via the interface 29.

  The control processor 26 (CPU) controls the operation of the apparatus main body 11 of the ultrasonic diagnostic apparatus 10 as an information processing apparatus. The control processor 26 reads out a control program for executing image generation / display, which will be described later, from the internal storage device 28, develops it on the software storage unit 27, and executes arithmetic / control related to various processes.

  The interface 29 is an interface related to the input device 13, the network, and a new external storage device (not shown). Data such as ultrasonic images and analysis results obtained by the apparatus can be transferred to another apparatus via the network by the interface 29.

[Configuration of Image Generation Circuit 24]
Next, the image generation circuit 24 which is an important point of the present invention will be described. FIG. 2 is a block diagram of the image generation circuit 24 according to the embodiment. As shown in FIG. 2, the image generation circuit 24 includes a scan converter 24a, a position detection circuit 24b, and an image composition circuit 24c. The scan converter 24a receives a received signal, which is a scanning line signal sequence of ultrasonic scanning output from the B-mode processing unit 22 or the Doppler processing unit 23, as a scanning line signal sequence of a general video format represented by a television or the like, That is, it is converted into a video signal. The position detection circuit 24b generates later-described position correction information related to the image display position based on the video signal output from the scan converter 24a. The image composition circuit 24c generates an ultrasonic image based on the video signal output from the scan converter 24a and the position correction information output from the position detection circuit 24b, and brightness and contrast are applied to the ultrasonic image. And image processing such as a spatial filter are performed or synthesized with character information and scales of various setting parameters and output to the monitor 14.

[Scan Sequence]
FIG. 3 is a flowchart of the scan sequence according to the embodiment. When the ultrasound scan is sequentially performed on the subject P, a plurality of reception signals S ₁ , S ₂ ,... Are obtained for each ultrasound scan. Note that the subscripts 1, 2,... Indicate the number of ultrasonic scans acquired by the scanning line signal sequence. That is, the reception signal S _i is a reception signal acquired by the i-th ultrasonic scan.

These received signals S ₁ , S ₂ ,... Are sent to the B-mode processing unit 22 to separate a fundamental wave component that is an echo signal from the tissue and a harmonic component that is an echo signal from the contrast agent. In addition, filtering is performed by a frequency filter. Thus, for each ultrasonic scan, a plurality of tissue signals So ₁ , So ₂ ,... That emphasizes the tissue shape and a plurality of blood flow signals Sb ₁ , Sb ₂ ,. Step S11).

The tissue signals So ₁ , So ₂ ,... And the blood flow signals Sb ₁ , Sb ₂ ,... It is converted into a scanning line signal sequence of a typical general video format.

Accordingly, the tissue signals So ₁ , So ₂ ,... And the blood flow signals Sb ₁ , Sb ₂ ,... Are respectively represented by a plurality of frames of tissue image information Go ₁ , Go ₂ ,. (First image information) and blood flow image information Gb ₁ , Gb ₂ ,... (Second image information) for a plurality of frames (step S12). The tissue image information Go ₁ ,... And the blood flow image information Gb ₁ , Gb ₂ ,... Are stored in the image memory 25 each time they are generated.

The tissue image information Go ₁ , Go ₂ ,... Is sent to the position detection circuit 24b (step S13), and position correction information between two consecutive frames Go _i-1 and Go _i is generated. In the present embodiment, as the position correction information, a movement vector V _i representing the shift width and the shift direction of the tissue image information Go _{i with} respect to the tissue image information Go _{i −1} is used (step S14).

[Generation of Movement Vector V _i ]
4A and 4B are conceptual diagrams of a generation process of the movement vector V _{i according to} the embodiment, where FIG. 4A is an image of the tissue image information Go _i-1 of the i−1 frame, and FIG. (C) shows an image of tissue image information Go _i-1 and Go _i superimposed so that the positions of the tissues T match, and (d) shows an image of the tissue image information Go _i of the eye. The generated movement vector V _i is shown. In addition, the code | symbol B in FIG. 4 represents the blood-vessel structure which exists on blood _- flow image information Gb _i-1 and Gb _i .

As shown in FIG. 4, the movement vector V _i is analyzed for the degree of superimposition while gradually shifting either _one of the tissue image information Go _i-1 and Goi, and the shift width when the spatial coincidence becomes the highest and It is generated from the deviation direction. There are various methods for obtaining the spatial coincidence. For example, a method of obtaining the absolute value of the luminance difference between the two tissue image information Go _i-1 and Go _i corresponding spatially, A method for obtaining a correlation function can be considered.

The blood flow image information Gb _i and the movement vector V _i are sent to the image synthesis circuit 24c (step S15), and the position of the blood flow image information Gb _i is corrected based on the movement vector V _i . Thus, the display position of the blood flow image information Gb _i is coincident with the display position of the blood flow image information Gb _i-1 of the previous one frame (see FIG. 4 (c).), Corrected blood that is position correction Stream image information H _i is generated (step S16). The corrected blood flow image information H _i is stored in the image memory 25 every time it is generated.

When n frames of corrected blood flow image information H ₁ , H ₂ ,..., H _n are stored in the image memory 25 by repeating the above procedure, these corrected blood flow image information H ₁ , H _{2 ,.} It was subjected to the maximum value holding operation (luminance value holding operation) using, to generate a luminance value holding image information I _n (step S17). The luminance value holding image information I _n is displayed each time it is generated on the monitor 14 as an ultrasonic image, it is used as a diagnostic material (step S18).

Incidentally, the maximum value holding operation, correction blood flow image information H _1, H 2, of _... H _n, and selecting and adopting the maximum luminance value from the luminance value of the pixel corresponding spatially, new image Is an arithmetic method for generating That is, the luminance value holding image information _{I n} is, as it were corrected blood flow image information _{H 1,} H 2, it can be said that by superimposing ... _{H n.}

Therefore, each time a new correction blood flow image information H _n is obtained, the Yuku are sequentially updated luminance value holding image information I _n, the monitor 14, and the contrast agent flows into the blood vessel over time The state of going is displayed in real time. Needless to say, the first frame of the luminance value holding image information I ₁ and the first frame of the corrected blood flow image information H ₁ are the same. Further, a general algorithm for the maximum value holding operation will be described in detail later.

[Operation according to this embodiment]
According to the ultrasonic diagnostic apparatus according to the present embodiment, based on the correlation value between the tissue image information Go _i and Go _i generated by the ultrasound scan, the positional deviation between the tissue image information Go _i-1 and Go _{i is} detected. A movement vector V _i to be expressed is generated, and the blood flow image information Gb _i is position-corrected based on the movement vector V _i .

Therefore, correction blood flow image information _{H 1,} H 2 that are sequentially generated, ... because the display position of the _{H n} match, these correction blood flow image information _{H 1,} H 2, ... the maximum value holding operation on the basis of the _{H n} It is performed, to generate a sharp luminance value holding image information I _n no blur, it is possible to perform delicate diagnosis as a result. As described above, the present invention exhibits particularly excellent effects when the “maximum value holding method” is used.

Further, according to the ultrasonic diagnostic apparatus according to the present embodiment, the tissue signals So ₁ , So ₂ ,... And the blood flow signals Sb ₁ , Sb ₂ ,. Is generated.

Therefore, since the tissue image information Go ₁ , Go ₂ ,... And the blood flow image information Gb ₁ , Gb ₂ ,... Represent the tissue state and blood flow state at exactly the same moment, the blood flow image information Gb ₁ , Position correction of Gb ₂ ... Can be performed accurately.

In the present embodiment, the tissue signals So ₁ , So ₂ ,... And the blood flow signals Sb ₁ , Sb ₂ ,... Are generated from one received signal S ₁ , S ₂ ,. It is not something.

For example, in ultrasonic scanning, ultrasonic transmission / reception is executed twice in the direction of one scanning line to generate blood flow signals Sb ₁ , Sb ₂ ,... From the first received signal, and from the second received signal. The tissue signals So ₁ , So ₂ ,... May be generated.

Specifically, in the first ultrasonic transmission, the transmission frequency is set to 2 MHz, the frequency filter of the B-mode processing unit 22 is set to 4 MHz, and a plurality of blood flow signals Sb ₁ , Sb ₂ , emphasizing blood flow components, ... is generated. Then, in the second ultrasonic transmission / reception, the transmission frequency is set to 4 MHz, the frequency filter of the B-mode processing unit 22 is set to 4 MHz, and a plurality of tissue signals So ₁ , So ₂ ,.

However, in this example, it is essential to generate tissue signals So ₁ , So ₂ ,... And blood flow signals Sb ₁ , Sb ₂ ... From _two ultrasonic transmissions / receptions, and the generation method is limited to this. It is not a thing.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment is an example in which color / power Doppler image information Gd ₁ , Gd ₂ ,... Is used instead of the blood flow image information Gb ₁ , Gb ₂ ,. is there.

[Scan Sequence]
FIG. 5 is a flowchart of a scan sequence according to the second embodiment of the present invention. When the ultrasonic scan is repeatedly performed on the subject P, reception signals S ₁ , S ₂ ,... Composed of a plurality of scanning line signal sequences are obtained for each ultrasonic scan.

These received signals S ₁ , S ₂ ,... Are sent to the B-mode processing unit 22 and the Doppler processing unit 23, and a plurality of tissue signals So ₁ , So ₂ ,. A plurality of color / power Doppler signals Sd ₁ , Sd ₂ ,... Are generated by the unit 23 (step S21).

The tissue signals So ₁ , So ₂ ,... And the color / power Doppler signals Sd ₁ , Sd ₂ ,... It is converted into a scanning line signal sequence of a general video format.

Accordingly, the tissue signals So ₁ , So ₂ ,... And the color / power Doppler signals Sd ₁ , Sd ₂ ,... Are tissue image information Go ₁ , Go ₂ for a plurality of frames in which the spatial positions in the living body are correctly arranged. ,... Are converted into color / power Doppler image information Gd ₁ , Gd ₂ ,... For a plurality of frames (step S22). The tissue image information Go ₁ , Go ₂ ,... And the color / power Doppler image information Gd ₁ , Gd ₂ ,.

The tissue image information Go ₁ , Go ₂ ,... Is sent to the position detection circuit 24b (step S23), and position correction information between two consecutive frames Go _i-1 and Go _i is generated. In the present embodiment, as the positional deviation information, a movement vector V _i representing the deviation width and deviation direction of the tissue image information Go _{i with} respect to the tissue image information Go _{i -1} is used (step S24).

Tissue image information Go _i, color / power Doppler information Gd _i, and the movement vector _{V i} is sent to the image synthesizing circuit 24c (step S25), and tissue image information Go _i and color / powered based on the movement vector _{V i} The position correction of the plastic image information Gd _i is performed.

Thereby, the display position of the tissue image information Go _{i and} the display position of the color / power Doppler image information Gd _i are respectively the display position of the tissue image information Go _i-1 and the color / power Doppler image information Gd. _The corrected tissue image information Jo _i and the corrected color / power Doppler image information K _i that coincide with the display position of _{i and} whose position is corrected are generated (step S26). The corrected tissue image information Jo _i and the corrected color / power Doppler image information K _i are stored in the image memory 25 each time they are generated, and are simultaneously superimposed and displayed on the monitor 14 as an ultrasonic image (step S27).

In the present embodiment, the corrected tissue image information Jo _i and the corrected color / power Doppler image information K _i are superimposed and displayed, but only the corrected color / power Doppler image information K _i may be displayed.

[Operation according to this embodiment]
Thus, according to the ultrasonic diagnostic apparatus according to the present embodiment, based on the tissue image information _{Go i-1, Go i} generated by ultrasonic scanning, the tissue image information _{Go i-1,} between Go _i of A movement vector V _i representing the positional deviation is generated, and the position of the color / power Doppler image information Gd _i is corrected based on the movement vector V _i .

Therefore, since the display positions of the tissue image information Go _i and the correction color / power Doppler image information K _i coincide with each other, when they are superimposed and displayed, the positional relationship between the tissue and the blood flow can be accurately understood, resulting in a delicate diagnosis. Can be performed.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment is a modification of the first embodiment, and the scan converter 24a uses the tissue image information Go ₁ , Go ₂ ,... And the blood flow image information Gb ₁ , Gb ₂ ,. ₁ , C ₂ ,... Are obtained, and correction information of these composite image information C ₁ , C ₂ ,.

[Configuration of Image Generation Circuit 24A]
FIG. 6 is a block diagram of an image generation circuit 24A according to the third embodiment of the present invention. As shown in FIG. 6, the image generation circuit 24A according to the present embodiment includes a scan converter 24a, a position detection circuit 24b, and an image synthesis circuit 24c, similarly to the image generation circuit 24 according to the first and second embodiments. Have. However, the flow of signal processing differs between the image generation circuit 24A according to the present embodiment and the image generation circuit 24 according to the first embodiment.

[Scan Sequence]
FIG. 7 is a flowchart of a scan sequence according to the embodiment. When the ultrasonic scan is repeatedly performed on the subject P, reception signals S ₁ , S ₂ ,... Composed of a plurality of scanning line signal sequences are obtained for each ultrasonic scan.

These received signals S ₁ , S ₂ ,... Are sent to the B-mode processing unit 22 to separate a fundamental wave component that is an echo signal from the tissue and a harmonic component that is an echo signal from the contrast agent. In addition, filtering is performed by a frequency filter. Thus, for each ultrasonic scan, a plurality of tissue signals So ₁ , So ₂ ,... That emphasizes the tissue shape, and a plurality of blood flow signals Sb ₁ , Sb ₂ ,. (Step S31).

These tissue signals So ₁ , So ₂ ,... And blood flow signals Sb ₁ , Sb ₂ ,... It is converted into a scanning line signal sequence of a general video format.

Accordingly, the tissue signals So ₁ , So ₂ ,... And the blood flow signals Sb ₁ , Sb ₂ ,... Are each a plurality of frames of tissue image information Go ₁ in which the spatial positions in the living body are correctly arranged. , Go ₂ ,... And blood flow image information Gb ₁ , Gb ₂ ,... (Step S32). The tissue image information Go ₁ , Go ₂ ,... And the blood flow image information Gb ₁ , Gb ₂ ,. Up to this point, the process is exactly the same as in the first embodiment.

The features of this embodiment will now be described. These tissue image information Go ₁ , Go ₂ ,... And blood flow image information Gb ₁ , Gb ₂ ,... Are synthesized by the scan converter 24a, and synthesized image information C ₁ , C ₂ ,. Is generated (step S33).

FIG. 8 is a schematic diagram when the composite image information C ₁ , C ₂ ,... According to the embodiment is visualized. As shown in FIG. 8, in the composite image information C ₁ , C ₂ ,..., The tissue region Ro occupied by the tissue image information Go ₁ , Go ₂ ,... And the blood occupied by the blood flow image information Gb ₁ , Gb ₂ ,. The flow region Rb is determined in advance. That is, in the present embodiment, the central portion of the composite image information C ₁ , C ₂ ,... Is the blood flow region Rb, and both side portions of the composite image information C ₁ , C ₂ ,.

The composite image information C ₁ , C ₂ ,... Is sent to the position detection circuit 24b (step S34), and position correction information between two consecutive frames C _i-1 and C _i is generated based on the tissue region Ro. Is done. In the present embodiment, as the position correction information, a movement vector U _i expressing the shift width and the shift direction of the tissue region Ro of the composite image information C _i with respect to the tissue region Ro of the composite image information C _i-1 is used ( Step S35).

The synthesized image information C _i and the movement vector U _i are sent to the image synthesis circuit 24c (step S36), and the position of the synthesized image information C _i is corrected based on the movement vector U _i . Thus, the display position of the tissue region Ro of the composite image information C _i coincides with the display position of the preceding frame of the composite image information C _i-1 tissue regions Ro. As a result, the display position of the blood flow region Rb of the composite image information C _i is coincident with the display position of the blood flow region of the preceding frame of the composite image information C _i, the position corrected corrected synthesized image information L _i It is generated (step S37). The corrected composite image information _Li is stored in the image memory 25 every time it is generated.

Correction synthetic image information _{L 1,} L 2 of the n frames in the image memory 25 by repeating the procedure, ... If _{L n} is stored, the correction synthetic image information _{L 1,} L 2, using ... _{L n} Then, the maximum value holding calculation is performed to generate luminance value holding image information M _n (step S38). The luminance value holding image information Mn is output to the monitor 14 as an ultrasonic image every time it is generated. Thereby, the state in which the contrast medium flows into the blood vessel as time passes is displayed on the monitor 14 in real time (step S39).

[Operation according to this embodiment]
Generating composite image information C ₁ , C ₂ ,... C _n based on tissue image information Go ₁ , Go ₂ ,... Generated by ultrasonic scanning and blood flow image information Gb ₁ , Gb ₂ ,. generating a motion vector U _i representing the positional deviation between the synthetic image information C _i-1 tissue regions Ro and the display position of the tissue region Ro of the composite image information C _i, and the composite image on the basis of the motion vector U _i information C _i are located corrected.

Thus, the composite image information C _1, C 2 are sequentially generated, _... because the display position of the C _n match, these synthetic image information C _1, C 2, subjected to the maximum value holding operation using the _... C _n However, it is possible to acquire clear brightness value holding image information M _n, and as a result, delicate diagnosis can be performed.

  In addition, since it is not necessary to perform correction and display while synchronizing two images as in the first embodiment, the apparatus configuration can be simplified compared to the first embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. The present embodiment is an example in which the present invention is applied to so-called “Micro Flow Imaging” in which the “recirculation method” and the “maximum value holding method” are combined. The details of the recirculation method are described in Patent Document 1 and will be briefly described here.

  In the present embodiment, a high sound pressure scan (first ultrasonic transmission) using a high sound pressure (first sound pressure) for collapsing the contrast agent bubble and a contrast agent bubble for acquiring an ultrasound image are not much. A low sound pressure scan (second ultrasonic transmission) with a low sound pressure (second sound pressure) that is not broken is alternately executed.

  That is, in this embodiment, at least one or more high sound pressure scans are performed in order to destroy the contrast agent bubbles in the scan section after performing the ultrasonic scans according to the first to third embodiments a plurality of times. To implement.

  In the present embodiment, as a contrast agent to be administered to the subject P, a so-called “next generation” capable of emitting a harmonic signal without being destroyed even when a low sound pressure ultrasonic wave is transmitted and being visualized for a long time. What is called "type contrast agent" is used.

[Scan Sequence]
FIG. 9 is a flowchart of a scan sequence according to the fourth embodiment of the present invention. First, a low sound pressure scan is repeatedly performed on the subject P, and reception signals P ₁ , P ₂ ,... Composed of a plurality of scanning line signal sequences are acquired for each low sound pressure scan (step S41).

These received signals P1, P2,... Are sent to the B-mode processing unit 22 to separate a fundamental wave component that is an echo signal from the tissue and a harmonic component that is an echo signal from the contrast agent. Filtering is performed by a frequency filter. Thus, for each low sound pressure scan, a plurality of tissue signals So ₁ , So ₂ ,... That emphasizes the tissue shape and a plurality of blood flow signals Sb ₁ , Sb ₂ ,. Step S42).

These tissue signals So ₁ , So ₂ ,... And blood flow signals Sb ₁ , Sb ₂ ,... Is converted into a scanning line signal sequence of a general video format. Accordingly, the tissue signals So ₁ , So ₂ ,... And the blood flow signals Sb ₁ , Sb ₂ ,... Are respectively converted into tissue image information Go ₁ , Go ₂ ,. Converted to image information Gb ₁ , Gb ₂ ,... (Step S43). The tissue image information Go ₁ , Go ₂ ... And the blood flow image information Gb ₁ , Gb ₂ ... Are stored in the image memory 25 each time they are generated.

The tissue image information Go ₁ , Go ₂ ,... Is sent to the position detection circuit 24b (step S44), and position correction information between two consecutive frames Go _i-1 and Go _i is generated. In the present embodiment, as the position correction information, a movement vector V _i that can express a shift width and a shift direction of the display position of the tissue image information Go _{i with} respect to the tissue image information Go _i-1 is used (step S45).

The blood flow image information Gb _i and the movement vector V _i are sent to the image synthesis circuit 24c (step S46), and the position of the blood flow image information Gb _i is corrected based on the movement vector V _i . Thus, the display position of the blood flow image information Gb _i is consistent with its previous frame of the display position of the blood flow image information Gb _i-1, the position corrected corrected blood flow image information H _i is generated ( Step S47). The corrected blood flow image information H _i is stored in the image memory 25 every time it is generated.

The Amendment of n frames in the image memory 25 by repeating the blood flow image information _{H 1,} H 2, ... When _{H n} is stored, the correction blood flow image information _{H 1,} H 2, ... to _{H n} based performs maximum value holding operation, to generate a luminance value holding image information I _n (step S48). The luminance value holding image information I _n is displayed each time it is generated on the monitor 14 as an ultrasonic image, it is used as a diagnostic material.

  By the way, when the number of executions of the low sound pressure scan increases, the inside of the tissue is filled with the contrast agent bubble, and the blood flow state of the blood vessel to be focused cannot be grasped. Therefore, the high sound pressure scan is executed when the number of executions of the low sound pressure scan reaches the predetermined number of times, and the maximum value holding calculation performed so far is initialized, that is, initialized (step S49). Thereby, the contrast agent bubble filled in the tissue of the subject P is destroyed, and the contrast agent bubble disappears from the luminance value holding image information In. The execution of the high sound pressure scan and the initialization of the maximum value holding calculation are started based on an instruction from the switch 13b.

When the high sound pressure scan is completed, the low sound pressure scan is executed again, and the luminance value holding image information I _2n is generated from the corrected blood flow image information H _{n + 1} , H _{n + 2} ,... H _2n (step S50). As described above, when the low sound pressure scan and the high sound pressure scan are alternately performed, the monitor 14 repeatedly displays the state in which the contrast agent flows into the blood vessel, and the change in the reflux state can be observed.

[Operation according to this embodiment]
According to the ultrasonic diagnostic apparatus according to the present embodiment, the present invention is applied to so-called “Micro Flow Imaging” in which the “reperfusion method” and the “maximum value holding method” are combined. Therefore, it is possible to clearly and repeatedly see the contrast agent flowing into the blood vessel.

  In addition, when the contrast agent bubble in the tissue is destroyed by the high sound pressure scan, the maximum value holding calculation so far is initialized. Therefore, it is possible to prevent the grasp of the blood vessel structure from being obstructed by the contrast agent bubble filling the tissue.

[Maximum value retention method]
Next, a general algorithm for holding a maximum value will be described. The maximum value holding method generates a new image by selecting the maximum value Pmax (x, y) from spatially corresponding luminance values in _n frames F _{1 to} F _n constituting an image. It is a method of doing.

Incidentally, a certain frame F _n consists of a set of spatially arranged P _n (x, y) or simply a set of one-dimensional luminance value array data P _n (x). As the value of P _n (x, y) or P _n (x), “signal intensity”, “signal amplitude”, “raw data such as RF data” or the like may be used instead of “luminance”. Good. Each of these data values generally means that the larger the numerical value, the higher the signal level of the echo signal.

When performing an operation based on the maximum value holding method, that is, the maximum value holding operation, using each of the data values described above, from n pixels spatially corresponding to n frames F _{1 to} F _n , The maximum luminance value Pmax (x, y) is selected based on the following formula [1].

Pmax (x, y) = max [P1 (x, y),..., P (x, y)] [1]
The algorithm for realizing the maximum value holding operation is not limited to the above contents. For example, the luminance value of each coordinate of the current frame F _i is P _i (x, y), the luminance value of the previous frame F _i−1 is P _n−1 (x, y), and these two The calculation process may be executed from i = 2 to n according to the following equation [2] using the frames F _i and F _i−1 .

If P _i (x, y)> P _i-1 (x, y),
then P _i (x, y) = P _i (x, y),
Else P _i (x, y) = P _i−1 (x, y)... [2]
This algorithm updates only the value of a pixel having a larger luminance value than the image related to the immediately preceding frame.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a block diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. FIG. 3 is a block diagram of an image generation circuit according to the embodiment. 6 is a flowchart of a scan sequence according to the embodiment. The conceptual diagram in the production | generation process of the movement vector which concerns on the same embodiment. 10 is a flowchart of a scan sequence according to the second embodiment of the present invention. The block diagram of the image generation circuit which concerns on 3rd Embodiment of this invention. 6 is a flowchart of a scan sequence according to the embodiment. FIG. 3 is a schematic diagram when a composite image according to the embodiment is visualized. The flowchart of the scan sequence which concerns on 4th Embodiment of this invention. The schematic diagram of the image showing the thick blood vessel into which abundant contrast agent flows. The schematic diagram of the some image showing the fine blood vessel with few flows of contrast agent. A schematic diagram of an image depicting even a minute blood flow. The schematic diagram of the image which represented the information of blood-flow running suitably.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Ultrasonic probe, 13b ... Switch (setting means), 14 ... Monitor (display means), 20 ... Image information generation part (generation means), 21 ... Transmission / reception unit (transmission means), 24b ... Position detection circuit (creation means) ), 24c ... image synthesizing circuit (synthesizing _{means), Go 1, Go 2,} ... Go n ... tissue image information (first image _{information), Gb 1, Gb 2,} ... Gb n ... blood flow image information (second image _{information), V 1, V 2,} ... V n ... moving vector (position correction information), I n _... luminance holding image _{information, C 1, C 2, ...} C n ... composite image information (third image information of ).

Claims (11)

In an ultrasonic diagnostic apparatus for acquiring an ultrasonic image by scanning a predetermined portion of a subject to which a contrast medium bubble is administered with an ultrasonic wave,
An ultrasonic probe for transmitting an ultrasonic wave to the subject and receiving an echo signal from the ultrasonic wave;
Transmitting means for performing ultrasonic transmission via the ultrasonic probe;
Based on the echo signal obtained by the ultrasonic transmission, first image information for a plurality of frames mainly for imaging a tissue and second image information for a plurality of frames for mainly imaging a blood flow are generated. Generating means;
A creation unit that creates position correction information of the i-th frame with respect to the i-1th frame from the correlation value between the i-1th frame and the i-th frame among the first image information generated by the generation unit. When,
Correction means for correcting the position of the i-th frame of the second image information generated by the generation means based on the position correction information generated by the generation means;
Display means for displaying the ultrasonic image based on the i-th frame of the second image information whose position is corrected by the correction means;
An ultrasonic diagnostic apparatus comprising: In an ultrasonic diagnostic apparatus for acquiring an ultrasonic image by scanning a predetermined portion of a subject to which a contrast medium bubble is administered with an ultrasonic wave,
An ultrasonic probe for transmitting an ultrasonic wave to the subject and receiving an echo signal from the ultrasonic wave;
Transmitting means for performing ultrasonic transmission via the ultrasonic probe;
Based on the echo signal obtained by the ultrasonic transmission, first image information for a plurality of frames mainly for imaging a tissue and second image information for a plurality of frames for mainly imaging a blood flow are generated. Generating means;
Third image information for a plurality of frames including the first and second image information generated by the generating unit and including a part of the first image information and a part of the second image information. A synthesis means for generating
Correlation value between the first image information included in the i-th frame of the third image information generated by the combining means and the first image information included in the i-frame of the third image information Generating means for generating position correction information of the i-th frame with respect to the i-1th frame;
Correction means for correcting the position of the i-th frame of the third image information based on the position correction information created by the creation means;
Display means for displaying the ultrasonic image based on the i-th frame of the third image information whose position is corrected by the correction means;
An ultrasonic diagnostic apparatus comprising:   3. The ultrasonic wave according to claim 1, wherein the generation unit generates the first image information and the second image information from the same echo signal acquired by the ultrasonic transmission. Diagnostic device.   3. The ultrasonic diagnosis according to claim 1, wherein the generation unit generates the first image information and the second image information from different echo signals obtained by the ultrasonic transmission. apparatus.   The generation unit generates luminance value holding image information by sequentially executing a luminance value holding calculation based on second image information for a plurality of frames whose positions have been corrected by the correction unit. Item 5. The ultrasonic diagnostic apparatus according to any one of Items 1 to 4.   The luminance value holding calculation generates the luminance value holding image information by selecting a maximum value from echo signals at spatially corresponding positions in the second image information for a plurality of frames whose positions are corrected by the correcting unit. 6. The ultrasonic diagnostic apparatus according to claim 5, wherein the maximum value holding calculation is performed.   The ultrasonic diagnostic apparatus according to claim 5, wherein the display unit displays the luminance value holding image information as the ultrasonic image. The generating means performs the frequency analysis based on the echo signal acquired by the ultrasonic transmission, and generates the second image information that visualizes the blood flow velocity,
The correcting unit corrects the position of the i-th frame of the second image information generated by the generating unit based on the position correction information generated by the generating unit;
The ultrasonic diagnostic apparatus according to claim 1, wherein the display unit displays the i-th frame of the second image information whose position is corrected by the correction unit as the ultrasonic image. The transmitting means includes a first ultrasonic scan with a first sound pressure that destroys the contrast agent bubble and a sound pressure that does not destroy the contrast agent bubble via the ultrasound probe, Performing a plurality of second ultrasound scans with a second sound pressure to image the reflux,
The ultrasonic wave according to claim 5, wherein the generation unit generates the second image information for the plurality of frames based on an echo signal obtained by the plurality of second ultrasonic scans. Diagnostic device.   The generation unit initializes the luminance value holding calculation when the first ultrasonic scan is executed, and obtains a position correction by the correction unit obtained by a plurality of second ultrasonic scans in the next stage. The ultrasonic diagnostic apparatus according to claim 9, wherein the luminance value holding image information is generated by sequentially executing a luminance value holding calculation based on the second image information for a plurality of frames.   11. The method according to claim 10, further comprising setting means for setting a reference frame for starting the luminance value holding calculation from second image information for a plurality of frames generated by the generating means. Ultrasonic diagnostic equipment.

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