JP2012245092A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus capable of detecting a reflection signal of a puncture needle reflected in a direction away from a probe and appropriately rendering the puncture needle.
An ultrasonic diagnostic apparatus according to an embodiment transmits a transmission beam corresponding to a predetermined transmission direction and a predetermined transmission focal point from the ultrasonic probe, and supports at least two reception directions different from the transmission direction. Generating at least two receive beams, and using the at least two receive beams, calculate a position of a predetermined reflector existing in a transmission region to which the transmission beam is transmitted and an echo signal from the reflector. The first ultrasonic image in which the reflector is visualized is generated using the calculated position of the reflector and the echo signal, and the first ultrasonic image is displayed.
[Selection] Figure 1

Description

  The present invention relates to an ultrasonic diagnostic apparatus that is used for imaging a tomography of an organ or the like by scanning the inside of a subject with an ultrasonic wave to perform image diagnosis of a disease or the like, or for monitoring an affected area in real time in a puncture operation or the like.

  An ultrasonic diagnostic apparatus is a diagnostic apparatus that displays an image of in-vivo information, and is cheaper, less exposed, and less invasive than other diagnostic imaging apparatuses such as an X-ray diagnostic apparatus and an X-ray computed tomography apparatus. It is used as a useful device for time observation. The application range of the ultrasonic diagnostic apparatus is wide, and it is applied to the diagnosis of circulatory organs such as the heart, abdomen such as the liver and kidney, peripheral blood vessels, obstetrics and gynecology, and breast cancer.

  Usually, an ultrasonic diagnostic apparatus transmits a focused ultrasonic wave (transmission beam) with a transmission direction along one scanning line (scanning direction) once, and performs reception by setting a focus in the transmission / reception direction. Diagnostic information (ultrasound image data) on the scanning line is acquired, and by sequentially changing the scanning direction and repeating the same ultrasonic transmission / reception for each scanning line, a two-dimensional or three-dimensional diagnostic image is finally generated. . In recent years, a method (simultaneous reception) of obtaining diagnostic information on a plurality of scanning lines by one transmission is also used. This is a method for transmitting a convergent ultrasonic wave, thereby giving parallel reception delays corresponding to a plurality of (different) reception directions within the main beam width of the transmission ultrasonic wave to echo signals obtained in each ultrasonic transducer. In other words, a plurality of reception beams corresponding to a plurality of directions are generated by executing delay addition a plurality of times. In ultrasonic image diagnosis, in order to obtain the best quality diagnostic image, the reception focus is generally set in the transmission direction, and ultrasonic transmission / reception with the transmission direction and the reception direction matched is generally performed. .

  By the way, the frame rate of the ultrasonic diagnostic apparatus is usually 30 Hz or higher, and it is a great feature that the dynamics of the organ or blood flow can be observed in real time. Taking advantage of this feature, ultrasonic diagnostic apparatuses are often used as guides for puncture needles. The use of puncture needles includes tissue collection (biopsy) and, in recent years, puncture techniques such as puncture acupuncture treatment in which microwaves and radio waves are emitted from the needle tip. The surgeon monitors in real time the state until the needle reaches a treatment site such as a tumor, for example, via an ultrasound image obtained using the ultrasound diagnostic image.

  As a conventional technique for improving the visibility of a puncture needle, for example, a phase difference between reception signals from two transmission pulses is detected, thereby superimposing the presence position of the needle from information on the movement of the puncture needle. One that generates a sound image (for example, refer to Patent Document 1), one that analyzes the phase information of an ultrasonic reception signal to extract features of an artifact from a living tissue (for example, refer to Patent Document 2), There are some which change a plurality of ultrasonic transmission directions and adopt an image composed of the strongest received signal as a needle image (see, for example, Patent Document 3).

JP 2006-150069 A JP 2009-254780 A Japanese Patent No. 438344

  However, the conventional ultrasonic diagnostic apparatus has the following problems with respect to the drawing performance of the puncture needle, for example. A normal puncture needle is made of metal and should reflect an ultrasonic pulse to a great extent, but there may be a case where it is not imaged as an echo signal. This is because the normal subject tissue is called a scatterer, which scatters the ultrasound in all directions and can be detected as a received signal even if it is weak, whereas the surface of the puncture needle is smooth, so the ultrasound is This is because specular reflection occurs. That is, if the reflection direction on the needle surface is an angle that returns to the probe, the puncture needle is imaged with a strong received signal. On the other hand, when the ultrasonic wave is incident on the needle obliquely, it is reflected in a direction different from that of the probe, so that the reflected signal from the needle is not received well. Therefore, in clinical practice, a technique may be employed in which the puncture needle is inserted at an angle that is as parallel as possible to the transducer of the ultrasonic probe. However, when the puncture target is in the deep part or when a convex probe is used, it is often difficult to create an angle at which the reflected signal returns to the probe.

  In view of the above circumstances, by combining transmission and reception in a completely different direction from conventional diagnostic methods, the reflected signal of the puncture needle reflected in the direction away from the probe is detected, and the puncture needle is depicted appropriately An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of performing the above.

An ultrasonic diagnostic apparatus according to an embodiment includes a plurality of ultrasonic transducers that generate an ultrasonic wave in response to a drive signal supplied thereto and generate an echo signal in response to the received ultrasonic wave. The ultrasonic probe and the drive signal given different transmission delays are supplied to the ultrasonic transducers, and the ultrasonic waves are generated from the ultrasonic transducers at a predetermined timing. A transmission means for transmitting a transmission beam corresponding to the transmission focal point of the ultrasonic probe from the ultrasonic probe, and a different reception delay for each ultrasonic transducer to each echo signal generated by each ultrasonic transducer, and the reception delay Receiving means for generating at least two reception beams corresponding to at least two reception directions different from the transmission direction by adding the respective echo signals given by A calculation means for calculating a position of a predetermined reflector existing in a transmission area where the transmission beam is transmitted and an echo signal from the reflector using the at least two reception beams; and the calculated reflection Image generating means for generating a first ultrasonic image in which the reflector is imaged using a body position and an echo signal; and display means for displaying the first ultrasonic image;
It is characterized by comprising.

FIG. 1 shows a block diagram of an ultrasonic diagnostic apparatus 1 according to the first embodiment. FIG. 2 is a schematic diagram showing a state in which a puncture needle that is a strong reflector is inserted obliquely into a scanned region (for example, in a two-dimensional cross section). FIG. 3 is a diagram showing a typical example of the sound field of convergent ultrasonic waves formed by electronic delay. FIG. 4 is a schematic diagram showing an ultrasonic propagation path when ultrasonic transmission / reception is executed in a state where the puncture needle is inserted obliquely into the scanned region. FIG. 5 is a diagram schematically showing echo signals on each scanning line obtained by transmission / reception according to the puncture needle rendering function. FIG. 6 is a diagram for explaining a signal value calculation method at each position of the puncture needle. FIG. 7 is a flowchart showing the flow of the puncture needle rendering process. FIG. 8 is a diagram showing echo signals on each scanning line obtained by transmission / reception according to the puncture needle rendering function. FIG. 9 is a diagram for explaining a puncture needle rendering function according to the second embodiment.

  Hereinafter, first and second embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

(First embodiment)
FIG. 1 shows a block diagram of an ultrasonic diagnostic apparatus 1 according to this embodiment. As shown in the figure, the ultrasonic diagnostic apparatus 1 includes an apparatus main body 11, an ultrasonic probe 12, an input device 13, and a monitor 14. The apparatus main body 11 includes an ultrasonic transmission unit 21, an ultrasonic reception unit 22, a B-mode processing unit 23, a Doppler processing unit 24, an image generation unit 25, an image memory 26, a display processing unit 27, a control processor 28, and a storage unit 29. An interface unit 30 is provided.

  The ultrasonic transmission unit 21 and the reception unit 22 incorporated in the apparatus main body 11 may be configured by hardware such as an integrated circuit, or may be a software program modularized in software. . Hereinafter, the function of each component will be described.

  The ultrasonic probe 12 generates ultrasonic waves based on a drive signal from the ultrasonic receiving unit 21 and converts a reflected wave from the subject into an electric signal, and a matching layer provided in the piezoelectric vibrator. And a backing material for preventing the propagation of ultrasonic waves from the piezoelectric vibrator to the rear. When convergent ultrasonic waves (transmission beams) are transmitted from the ultrasonic probe 12 to the subject P, the transmitted ultrasonic waves are reflected one after another on the discontinuous surface of the acoustic impedance of the body tissue, and the ultrasonic probe is used as an echo signal. 12 is received. The amplitude of this echo signal depends on the difference in acoustic impedance at the discontinuous surface that is to be reflected. In addition, the echo when the transmitted ultrasonic pulse is reflected by the moving blood flow or the surface of the heart wall or the like depends on the velocity component in the ultrasonic transmission direction of the moving object due to the Doppler effect, and the frequency deviation. Receive a move.

  The input device 13 is connected to the device main body 11, and includes various switches, buttons, tracks 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. In addition to the ball, it has a mouse, a keyboard, and the like.

  The monitor 14 displays in vivo morphological information and blood flow information as an image based on the video signal from the image generation unit 25.

  The ultrasonic transmission unit 21 includes a pulse generator 21A, a transmission delay unit 21B, and a pulsar 21C. In the pulse generator 21A, a rate pulse for forming a transmission ultrasonic wave is repeatedly generated at a predetermined rate frequency fr Hz (period: 1 / fr second). Further, in the transmission delay unit 21B, the delay time (transmission delay) necessary for focusing the ultrasonic wave into a beam shape for each channel and determining the transmission directivity (transmission direction) is included in each rate pulse for each transducer. Given. The pulsar 21C applies a drive signal (drive pulse) to the probe 12 at a timing based on this rate pulse.

  The ultrasonic reception unit 22 includes a preamplifier 22A, an A / D converter 22B, a reception delay unit 22C, an adder 22D, and the like. The preamplifier 22A amplifies the echo signal captured via the probe 12 for each channel. The A / D converter 22B converts the echo signal as an analog signal into a digital signal. In the reception delay unit 22C, a delay time (reception delay) necessary for determining the reception directivity (reception direction) is given to the echo signal for each transducer, and thereafter, an adder 22D performs addition processing. By this addition, the reflection component from the direction corresponding to the reception directivity of the echo signal is emphasized, and a comprehensive reception beam for ultrasonic transmission / reception is formed by the reception directivity and the transmission directivity.

The form of the output signal immediately after the ultrasonic receiving unit 22 may be various forms such as a signal including phase information called a radio frequency (RF) signal, or amplitude information after envelope detection processing. Can be selected.
The B-mode processing unit 23 receives the echo signal from the receiving unit 22 and performs logarithmic amplification, envelope detection processing, and the like, and generates data for each scanning line whose signal intensity is expressed by brightness. This data is transmitted to the image generation unit 25 and is displayed on the monitor 14 as a B-mode image in which the intensity of the reflected wave is represented by luminance.

  The Doppler processing unit 24 performs frequency analysis on velocity information from the echo signal received from the receiving unit 22, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and obtains blood flow information such as average velocity, variance, and power. Ask for multiple points. The obtained blood flow information is sent to the image generation unit 25 and 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 unit 25 converts a plurality of scanning line signal sequences obtained by ultrasonic scanning into a scanning line signal sequence of a general video format represented by a television or the like, and converts an ultrasonic diagnostic image as a display image. Generate. The image generation unit 25 is equipped with a storage memory for storing image data. For example, an operator can call up an image recorded during an examination after diagnosis. Furthermore, the image generation unit 25 performs predetermined processing such as volume rendering, multi-planar reconstruction display (MPR), maximum intensity projection (MIP), and the like on the obtained volume data as necessary. Perform image processing. Note that data before entering the image generation unit 25 may be referred to as “raw data”.

  The image memory 26 includes a storage memory for storing scanning line data received from the B mode unit 23 or the Doppler processing unit 24. The scanning line data can be called by an operator after diagnosis, for example, and becomes an ultrasound diagnostic image via the image generation unit 25. This image can be reproduced as a still image or as a moving image using a plurality of images.

  The display processing unit 27 executes various types such as dynamic range, brightness (brightness), contrast, γ curve correction, and RGB conversion on various image data generated and processed by the image generation unit 25.

The control processor 28 has a function as an information processing apparatus (computer) and controls the operation of the main body of the ultrasonic diagnostic apparatus. The control processor 28 reads, from the storage unit 29, a dedicated program for realizing a puncture needle rendering function, which will be described later, and a dedicated program for executing various calculation processes, and executes calculation / control and the like related to the various processes. In particular, the control processor 28 reads the transmission delay pattern and the reception delay pattern stored in the storage unit 29, and switches the transmission delay and the reception delay according to the transmission direction and the reception direction. The transmission / reception delay pattern in the puncture needle rendering function described later can also be controlled by the processor.
The storage unit 29 realizes a puncture needle position in a puncture needle rendering function (to be described later), an estimation calculation of a signal value at the puncture needle position, display of an ultrasonic image generated using the estimated puncture needle position, and the like Dedicated program for executing various calculation processes, such as a dedicated program for transmission, a plurality of combination patterns for transmission delay, a plurality of combination patterns for reception delay, etc., for executing a predetermined scan sequence, image generation, and display processing A control program, diagnostic information (patient ID, doctor's findings, etc.), diagnostic protocol, transmission / reception conditions, and other data groups are stored. Further, it is also used for storing images in the image memory 26 as necessary. Data in the storage unit 29 can be transferred to an external peripheral device via the interface unit 30.

  The interface unit 30 is an interface related to the input device 13, a network, and a new external storage device (not shown). Data such as ultrasonic images and analysis results obtained by the apparatus can be transferred by the interface unit 30 to another apparatus via a network.

(Puncture needle rendering function)
Next, the puncture needle rendering function provided in the ultrasonic diagnostic apparatus will be described. This function detects the reflected signal of the puncture needle reflected in the direction away from the probe by combining transmission and reception in a direction completely different from the conventional diagnostic method, and appropriately displays the puncture needle.

  FIG. 2 is a schematic diagram showing a state in which a puncture needle that is a strong reflector is inserted obliquely into a scanned region (for example, in a two-dimensional cross section). The ultrasound reflection mechanism of the puncture needle generated in the scanned region and the rendering method realized in the present puncture needle rendering function using the mechanism will be described with reference to FIG. It should be noted that the sound field (ie, the transmission beam and the reception beam) of the convergent ultrasonic wave formed by the electronic delay has a shape that converges at the focal point, for example, as indicated by B1 in FIG. However, in the example shown in FIG. 2 and the following description, for the sake of concrete explanation, the center line 102 representing the beam is used to represent the transmission direction T1, the reception direction R1, R2, or the scanning line. Shall. For the sake of simplicity, it is assumed that the scanning lines along the transmission direction T1 and the reception directions R1 and R2 are parallel.

  In the present puncture needle rendering function, as shown in FIG. 2, the reception direction R1 is set at a position substantially deviated from the width of the main beam formed by transmission ultrasonic waves. In normal ultrasonic image diagnosis, the reception focus is generally set in the transmission direction, and ultrasonic transmission / reception in which the transmission direction matches the reception direction is generally performed. Therefore, depending on the ultrasonic transmission / reception that does not match the transmission direction and the reception direction as shown in FIG. 2, the echo signal obtained by normal ultrasonic transmission / reception is substantially obtained (the transmission direction and the reception direction are matched). I can't do it.

  However, as shown in FIG. 2, the transmission ultrasonic wave is actually reflected at the same angle θ as the incident angle θ at the position where the transmission direction T1 intersects the puncture needle (point A), and becomes a reflected beam. Propagate in the direction of B. The scatterer existing at the position B scatters the reflected beam, and as a result, the scatterer is received as a reception beam whose reception direction is R1.

  That is, the propagation path of the ultrasonic wave in the transmission / reception passes through the scanning line along the transmission direction T1 from the ultrasonic transducer, passes through the scanning line along the reception direction R1 via A and B, and returns to the transducer again. It will be back. In the actual ultrasonic diagnostic apparatus, the echo signal acquired through the path appears as a signal from a position (point C) where the reciprocal propagation distance is equal on the scanning line along the reception direction R1. On the other hand, since the reception direction R1 is substantially deviated from the transmission direction T1 from other positions on the scanning line along the reception direction R1, a proper echo signal cannot be acquired. As a result, on the scanning line along the reception direction R1, the echo signal at the position C is relatively emphasized and reception data is obtained.

  FIG. 4 shows an ultrasonic propagation path when ultrasonic transmission / reception is executed with the transmission direction as T1 and the reception direction as R2 in a state where the puncture needle is obliquely inserted into the scanned region (for example, in a two-dimensional cross section). It is the schematic diagram which showed. As shown in the figure, the reception direction R2 is located on the opposite side of the reception direction R1 with respect to the transmission direction T1. When the intersection between the scanning line along the receiving direction R2 and the puncture needle is expected from the scanning line along the transmission direction T1, the scattered echo generated at the position (point A ′) at the angle θ due to the transmission beam is , Reflected at the position B (point B), returns to the ultrasonic transducer through the scanning line along the reception direction R2. That is, the propagation path at this time passes through the scanning line along the transmission direction T1 from the transducer, passes through the scanning line along the reception direction R2 via the position A ′ and the position B ′, and again returns to the transducer. It will be back. As a result, on the scanning line along the reception direction R2, the echo signal at the position C 'is relatively emphasized, and reception data is obtained. As described above, the echo signal reflected by the puncture needle can be received using the transmission beam along the transmission direction T1.

  By the way, the positions C and C ′ are different from the actual depth d of the puncture needle on the scanning line along the transmission direction T1. Therefore, even if the echo signals obtained from the position C and the position C ′ are superimposed on the scanning line along the transmission direction T1, the puncture needle is not correctly drawn. However, for example, if the echo signal acquired in each reception direction is visualized while shifting the transmission and reception positions little by little while maintaining the relative positional relationship between the transmission direction T1 and the reception direction R1, as a result, FIG. A linear pattern as shown in 51 is obtained as a two-dimensional image. Similarly, if the echo signal in each reception direction is visualized while shifting the reception position little by little while maintaining the relative positional relationship between the transmission direction T1 and the reception direction R2, as shown in 52 of FIG. Can be obtained. At this time, it is clear that the position of the puncture needle exists between the pattern 51 and the pattern 52.

  The position of the puncture needle existing between the pattern 51 and the pattern 52 in FIG. 5 can be estimated by, for example, the following analytical (mathematical) technique. That is, as shown in FIGS. 2 and 4, the distance of each scanning line is w, the depth of the puncture needle existing on the scanning line along the transmission direction T1 (the actual depth from the subject surface) is d, The depth at which the position C appears (false observation point D1) is d + h, and the incident angle (reflection angle) is θ. For the sake of simplicity, the scanning lines are parallel, and θ is the same everywhere.

The depth at which the position C appears (false observation point D1) can be expressed by the following equation (1).

Here, h can be expressed by the following equation (2).

Next, considering the receiving direction R2 existing on the opposite side of the receiving direction R1 with respect to the transmitting direction T1, the distance B′C ′ is equal to h because of the geometric relationship. The difference in depth between A and B ′ is w / tan θ. Therefore, the observation depth D2 at the position C ′ can be expressed by the following equation (3).

The difference in depth between the observation points D1 and D2 can be expressed by the following equation (4).

  Here, the observation point depths D1 and D2 can be acquired by actual observation by ultrasonic transmission / reception. If the observation depths D1 and D2 are known, θ is found from the equation (4), h is found from the equation (2), and finally the depth d of the puncture needle is found from the equation (1).

  The distance h is equal to “the difference between the observation depth D1 and the true depth”. Therefore, the luminance observed on the scanning line along the reception direction R1 is drawn by shifting the luminance upward on the scanning line along the transmission direction T1 by h (that is, shifted from point C to point A). Thus, the luminance can be mapped to the position of the true (real) puncture needle.

By the way, it is desirable that the positions of the observation point depths D1 and D2 are clearly and singly detected. However, in actuality, as shown in FIG. 6, it is expected to be detected as a blurred and wide state. Therefore, the mutual correlation coefficient R12 of both is defined by the following equation (5).

However, in Expression (5), I ₁ (t) and I ₂ (t) are amplitude values (or echo intensities) at depth t on each scanning line along the reception directions R1 and R2, respectively, E []. Means the expected value in [].

  The procedure for reconstructing an image in which a puncture needle is drawn on a scanning line along the transmission direction T1 is as follows.

First, a coefficient α (x) based on the magnitude of the cross-correlation coefficient of signals on the scanning lines in the receiving directions R1 and R2 is defined by the following equation (6), for example.

Next, the coefficient α (x) is calculated by gradually shifting x in the equation (6), and the “mixing ratio” of the corresponding I ₁ (t) is calculated by the following equation (7).

The data of one scanning line corresponding to one reception direction thus obtained corresponds to the ultrasonic signal value reflected by the puncture needle. When the signal value is drawn on the scanning line along the transmission direction T1, an image with enhanced brightness can be generated at the intersection of the scanning line along the transmission direction T1 and the puncture needle. Incidentally, the shift width when calculating the cross-correlation coefficient R12, shifting width for overlapping with I ₁ is necessary to be careful different.

  By executing the analytical method described above for the corresponding points on the pattern 51 and the pattern 52 shown in FIG. 5, each position on the puncture needle is mapped, and as a result, the puncture needle is suitably depicted. 2D images can be acquired.

  In the above description, the case where the scanning line corresponding to the transmission direction and the scanning line group corresponding to the reception direction are parallel to each other has been described. On the other hand, the puncture needle rendering function according to the above embodiment can be applied even when the scanning line group has a fan shape like a sector probe. In such a case, the reflection angle (incident angle) θ changes for each scanning line. Even in such a case, the same analysis can be performed using the geometric relationship.

(Operation)
Next, a process (puncture needle rendering process) according to the puncture needle rendering function realized by the ultrasonic diagnostic apparatus will be described.

  FIG. 7 is a flowchart showing the flow of the puncture needle rendering process. The contents of processing executed in each step will be described with reference to FIG.

[Input of patient information, imaging mode, etc .: Step S1]
First, input of patient information via the input device 13, transmission / reception conditions (scanned region, focal position, transmission voltage, positional relationship between the transmission direction and the reception direction, etc.), ultrasonic scanning of a predetermined region of the subject Input / selection of imaging mode, scan sequence, etc. is executed (step 1). Various information / conditions inputted and selected are automatically stored in the storage unit 31. Here, the puncture needle rendering mode is selected as the imaging mode.

[Ultrasonic scanning for puncture needle rendering: Step S2]
Next, the control processor 28 controls the ultrasonic transmission unit 21 and the ultrasonic reception unit 22 so that the ultrasonic scanning for puncture needle rendering is executed (step S2). That is, for example, the control processor 28 controls the ultrasonic transmission unit 21 so that ultrasonic transmission is performed with the transmission direction T1 and a predetermined position on the T1 as a transmission focal point, and the reception direction is R1. The ultrasonic receiving unit 22 is controlled so that ultrasonic reception is executed. Thereby, the reception data corresponding to the scanning line along the reception direction R1 is acquired. Similarly, the control processor 28 controls the ultrasonic transmission unit 21 so that, for example, ultrasonic transmission with the transmission direction T1 is executed, and ultrasonic waves so that the ultrasonic reception with the reception direction R2 is executed. The receiving unit 22 is controlled. Thereby, the reception data corresponding to the scanning line along the reception direction R2 is acquired.

  Further, the control processor 28 changes the positions in the transmission direction and the reception direction little by little (while gradually shifting) while maintaining the relative positional relationship between the transmission direction and the reception direction, Perform sonic scanning multiple times. As a result, reception data such as the pattern 51 and the pattern 52 shown in FIG. 5 can be acquired on the scanning line along each reception direction. FIG. 8 shows an actual image acquired by the inventors. In the figure, pattern 81 and pattern 82 correspond to pattern 51 and pattern 52, respectively.

[Puncture Needle Position / Puncture Needle Signal Value Calculation: Step S3]
Under the control of the control processor 28, the image generation unit 25 calculates the puncture needle position and the ultrasonic signal value (puncture needle signal value) reflected by the puncture needle based on the obtained received signal (step S3). ). In other words, the image generation unit 25 has a geometric relationship (positional relationship) between one transmission direction and at least two reception directions acquired with reference to the transmission direction, sound speed, and each scanning line along each reception direction. Based on the reception timing at, the analysis using the above-described equations (1) to (4) is executed, and the puncture needle position is calculated. Further, the image generation unit 25 performs analysis using the above-described equations (5) to (7) using the received signals on each scanning line along each receiving direction, and calculates the puncture needle signal value. . The calculation for obtaining the puncture needle position and the puncture needle signal value is executed for each puncture needle rendering ultrasonic scan.

[Generation / Display of Punctured Needle Image: Step S4]
Each process in steps S1 to S3 is repeatedly executed for each frame. The image generation unit 25 maps the corresponding puncture needle signal value to each puncture needle position calculated in step S3, thereby generating a puncture needle rendered image for each frame in which the locus of the puncture needle is clearly indicated. The puncture needle rendered image is generated in real time for each frame. Each puncture needle rendered image is subjected to a predetermined display process in the display processing unit 27 and then superposed on or parallel to a B-mode tomographic image that is acquired as needed together with, for example, the puncture needle rendered image on the monitor 14. Displayed in real time (step S4).

(Modification 1)
In the above description, the received signal on the scanning line along the receiving direction R1 and the received signal on the scanning line along the receiving direction R2 opposite to the receiving direction R1 with respect to the transmitting direction T1 are used. An example of calculating the position and signal value is shown. However, the present puncture needle rendering function is not limited to this example, and the reception signal on the scanning line along the reception direction R1 and the reception different from the reception direction R2 on the same side as the reception direction R1 with respect to the transmission direction T1. The position and signal value of the puncture needle may be calculated by the same analysis using the received signal on the scanning line along the direction R3. That is, according to the present puncture needle rendering function, by using the received signals corresponding to one transmission direction and at least two reception directions acquired with reference to the transmission direction and their geometrical relationship, The exact position and the signal value at that position can be calculated.

(Modification 2) Another example of feature extraction>
In the embodiment described above, for example, the position of the puncture needle is obtained by an analytical method according to equations (1) to (4), and the puncture needle signal value is obtained by an analytical method according to equations (5) to (7). . On the other hand, for example, the position of the puncture needle may be obtained by extracting a predetermined feature amount using the pattern 51 and the pattern 52 shown in FIG. Many methods for extracting features such as straight lines from images have been reported for a long time in the field of image processing. Also in this puncture needle rendering function, for example, a typical feature amount extraction algorithm such as a Hough transform can be used. In such a case, a dedicated program for executing the algorithm is stored in the storage unit 29. For example, in step S3, feature amount extraction is performed using the dedicated program, and the extracted linear pattern is obtained as a result. As a result, a puncture needle rendering image in which each puncture needle signal value is mapped to an appropriate position can be generated.

(effect)
In the ultrasonic diagnostic apparatus described above, a plurality of reception directions are set at positions substantially deviating from the width of the main beam T formed by transmission ultrasonic waves, and acquired in correspondence with the reception directions. Using a plurality of received beams, geometrical analysis or feature value extraction of the position of a predetermined reflector (puncture needle) existing in the ultrasonically scanned region and the signal value corresponding to each position of the reflector Calculate by Then, a puncture needle rendered image is generated by mapping a signal value corresponding to the calculated position of the reflector, and is displayed in real time together with a normal B-mode tomographic layer. Therefore, the operator can simultaneously observe in real time the puncture needle rendered image and the B-mode image in which the puncture needle is accurately depicted, and can accurately and quickly visually recognize the puncture needle in the subject. As a result, it is possible to contribute to quality improvement in puncture or the like that performs monitoring using an ultrasonic diagnostic apparatus.

(Second Embodiment)
A puncture needle rendering function according to the second embodiment will be described. The puncture needle rendering function according to the present embodiment acquires reception signals corresponding to a plurality of reception directions by parallel simultaneous reception, and calculates puncture needle positions and puncture needle signal values based on the reception signals.

  FIG. 9 is a diagram for explaining a puncture needle rendering function according to the present embodiment. In this embodiment, in order to perform parallel simultaneous reception, by sequentially changing the interval between the transmission direction T1 and the reception direction R1, a plurality of scanning lines along the reception direction R1 (in the example of FIG. 7, a, b, It is assumed that a reception beam corresponding to five of c, d, and e) is formed. A plurality of reception beams having substantially different directivities are subjected to reception processing in which, for example, the reception delay of the preamplifier 22A is changed for each channel with respect to one transmission beam along the transmission direction T1. Is possible.

  If necessary, ultrasonic transmission / reception is performed a plurality of times, such as beam transmission to T1, beam reception from R1-a, beam transmission to T1, beam reception from R1-b, and so on. You may make it do.

  The reception signals obtained from the scanning lines R1-a to R1-e include a reflection signal from the puncture needle that intersects the transmission direction T1 as described above. The image generation unit 25 uses this reflected signal to generate a pattern 53 shown in FIG. 7, for example, by mapping on each of the scanning lines R1-a to R1-e according to the method described based on the geometric relationship. . Further, the image generation unit 25 regards the pattern 53 as a line and performs a predetermined feature amount extraction such as a Hough transform to obtain an intersection with the transmission direction T1. Thereby, the position of the puncture needle in the transmission direction T1 (that is, the reflection position of the transmission beam on the puncture needle) can be estimated, and the position of the puncture needle can be obtained.

  Even with the configuration described above, the same effects as those of the first embodiment can be realized.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Specific examples of modifications are as follows.

  (1) Each function according to the present embodiment can also be realized by installing a program for executing the processing in a computer such as a workstation and developing the program on a memory. At this time, a program capable of causing the computer to execute the technique is stored in a recording medium such as a magnetic disk (floppy (registered trademark) disk, hard disk, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory. It can also be distributed.

  (2) In each of the embodiments described above, the locus of the puncture needle calculated from, for example, the pattern 51 and the pattern 52 shown in FIG. However, the present invention is not limited to this example. For example, the pattern 51 and the pattern 52 may be displayed together with the trajectory of the puncture needle. In such a case, it is preferable to display the trajectory of the puncture needle in a form in which the pattern 51 and the pattern 52 are distinguishable.

  (3) In each of the above embodiments, the case where the scanned region is a two-dimensional region (two-dimensional cross section) is taken as an example. On the other hand, it is also possible to perform puncture needle drawing with the scanned region as a three-dimensional region. In such a case, the position of a predetermined reflector existing in the scanned region and the signal value corresponding to each position of the reflector may be calculated by three-dimensional geometric analysis or feature amount extraction. .

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic diagnostic apparatus, 11 ... Apparatus main body, 12 ... Ultrasonic probe, 13 ... Input device, 14 ... Monitor, 21 ... Ultrasonic transmission unit, 22 ... Ultrasonic reception unit, 23 ... B mode processing unit, 24 ... Doppler processing unit, 25 ... image generation unit, 26 ... image memory, 27 ... display processing unit, 28 ... control processor (CPU), 29 ... storage unit, 30 ... interface unit

Claims (6)

An ultrasonic probe having a plurality of ultrasonic transducers each generating an ultrasonic wave in response to a supplied drive signal and generating an echo signal in response to the received ultrasonic wave;
A transmission beam corresponding to a predetermined transmission direction is generated by supplying the drive signals given different transmission delays to the ultrasonic transducers and generating the ultrasonic waves from the ultrasonic transducers at a predetermined timing. Transmitting means for transmitting from the ultrasonic probe;
Different transmission delays are given to the respective echo signals generated by the respective ultrasonic transducers for each of the ultrasonic transducers, and the respective echo signals to which the reception delays are added are added to be different from the transmission direction. Receiving means for generating at least two receive beams corresponding to at least two receive directions;
A calculation means for calculating a position of a predetermined reflector existing in a transmission region to which the transmission beam is transmitted and an echo signal from the reflector using the at least two reception beams;
Image generation means for generating a first ultrasonic image in which the reflector is imaged using the calculated reflector position and echo signal;
Display means for displaying the first ultrasonic image;
An ultrasonic diagnostic apparatus comprising:   The reception means generates a first reception beam corresponding to a first reception direction different from the transmission direction, and a second direction located on the opposite side with respect to the first reception direction and the transmission direction. The ultrasonic diagnostic apparatus according to claim 1, wherein at least a reception beam to be generated is generated.   The reception means is a first reception beam corresponding to a first reception direction different from the transmission direction, and the first reception direction is located on the same side with respect to the first reception direction and the transmission direction. The ultrasonic diagnostic apparatus according to claim 1, wherein at least a reception beam generated in a third direction different from the generation direction is generated.   The calculation means calculates a position of a predetermined reflector and an echo signal from the reflector using a geometric relationship between the transmission direction and the at least two reception directions. The ultrasonic diagnostic apparatus according to claim 1.   4. The calculation unit according to claim 1, wherein the calculation unit calculates a position of a predetermined reflector and an echo signal from the reflector by a feature amount extraction process using the at least two reception directions. The ultrasonic diagnostic apparatus according to one item.   2. The display unit according to claim 1, wherein the display unit displays the first ultrasonic image and a B-mode image in which a structure in the transmission area is visualized in a superimposed manner or in parallel. The ultrasonic diagnostic apparatus according to any one of 5.

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