JP5041907B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic beam scanning technique.

  In general, in an ultrasonic diagnostic apparatus, the image range of a diagnostic image, that is, the scan range of the ultrasonic beam, the frame rate of the diagnostic image, that is, the number of scans of the scanning range per unit time, and the resolution of the diagnostic image are mutually There is a trade-off relationship. For example, when trying to obtain a wide range of diagnostic images with high resolution, the frame rate is low, and when trying to obtain a high resolution image while maintaining the frame rate, it is necessary to narrow the image range.

  In contrast, for example, in Patent Documents 1 and 2, a wide area image is formed by scanning an ultrasonic beam relatively coarsely, and a narrow area image is formed by scanning an ultrasonic beam relatively densely. A technique for synthesizing narrow area images to form a synthesized image is described. With this technique, it is possible to achieve a high resolution within a limited narrow range while suppressing a decrease in the frame rate.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a technique for narrowing the beam interval by forming a beam interpolated between beams for data with a coarse beam interval. Incidentally, Patent Document 4 describes a technique for individually setting beam forming conditions such as a beam address and a beam length for each beam line constituting a beam scanning space.

JP 2005-152346 A JP 2000-232978 A JP 2001-231781 A JP 2004-275223 A

  As described above, several attempts have been made to align image ranges, frame rates, and resolutions for diagnostic images that are in a trade-off relationship with each other without degrading as much as possible. With this situation as the background, the present inventor has conducted research and development on a technique for satisfactorily aligning the image range, the frame rate, and the resolution. In particular, we focused on the ultrasonic beam scanning technology.

  The present invention has been made in the course of its research and development, and an object thereof is to provide an ultrasonic beam scanning technique that satisfactorily aligns an image range, a frame rate, and a resolution.

  In order to achieve the above object, an ultrasonic diagnostic apparatus according to a preferred embodiment of the present invention scans an ultrasonic beam by controlling a plurality of vibration elements and a probe including a plurality of vibration elements that transmit and receive ultrasonic waves. A transmitting / receiving unit, an image forming unit that forms ultrasonic image data based on a reception signal obtained from the scanning region via an ultrasonic beam, and a display unit that displays an ultrasonic image corresponding to the ultrasonic image data The transmission / reception unit sequentially forms an ultrasonic beam corresponding to each of a plurality of beam numbers based on beam position data calculated for each beam number, thereby generating an ultrasonic beam in the scanning region. The beam position data is calculated using beam interval data corresponding to the beam interval of the ultrasonic beam that is changed in accordance with the position of the region of interest within the scan region. The features.

  In a preferred aspect, the beam interval data is calculated using minimum beam interval data corresponding to the minimum value of the beam interval and a pitch conversion coefficient for adjusting the beam interval according to the beam number. To do.

  In a preferred aspect, the pitch conversion coefficient includes region end position data corresponding to the beam position of the ultrasonic beam at the region end of the scanning region, and region end beam number corresponding to the beam number of the ultrasonic beam at the region end of the scanning region. And the minimum beam interval data.

  In a desirable aspect, the probe includes a user operation device that receives a change operation for at least one of the minimum beam interval data and the pitch conversion coefficient.

  In a preferred embodiment, the beam interval data includes a step coefficient corresponding to the number of steps of the beam interval changed in stages, scan angle data corresponding to the size of the scan region, and ultrasonic waves formed in the scan region. It is calculated based on beam number data corresponding to the number of beams.

  In a preferred aspect, the transmission / reception unit forms a reception beam corresponding to each of a plurality of beam numbers based on beam position data calculated for each beam number using the beam interval data, and is adjacent to each other. By forming one transmission beam in the middle of the two reception beams, transmission / reception processing in which the two reception beams correspond to the one transmission beam is performed.

  The present invention provides a scanning technique of an ultrasonic beam that satisfactorily aligns an image range, a frame rate, and a resolution.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a functional block diagram showing the overall configuration thereof.

  The probe 10 is an ultrasonic probe that transmits and receives ultrasonic waves, and includes a plurality of vibration elements. The plurality of vibration elements, for example, are arranged in one row and electronically controlled to transmit and receive ultrasonic waves two-dimensionally within the scanning region 30. Note that ultrasonic waves may be transmitted and received three-dimensionally by arranging a plurality of vibration elements two-dimensionally in a lattice shape and electronically controlling.

  The transmission / reception unit 12 outputs a transmission signal corresponding to each of the plurality of vibration elements included in the probe 10. The transmission / reception unit 12 applies a delay process or the like corresponding to the vibration element to the transmission signal of each vibration element. The transmission signal output from the transmission / reception unit 12 is supplied to each vibration element of the probe 10. That is, the transmission / reception unit 12 functions as a transmission beamformer, each vibration element vibrates in accordance with a transmission signal formed by the transmission / reception unit 12, an ultrasonic transmission beam is formed, and scanning of the transmission beam is controlled. The ultrasonic transmission beam is scanned within a fan-shaped scanning region 30 having a vertex angle θ, for example.

  In addition, the transmission / reception unit 12 forms a reception beam based on reception signals obtained from a plurality of vibration elements included in the probe 10. The transmission / reception unit 12 performs a delay process or the like according to the vibration element on the reception signal of each vibration element, and adds the reception signals obtained from the plurality of vibration elements. That is, the transmission / reception unit 12 functions as a reception beam former, and forms reception beam data by performing, for example, phasing addition processing on reception signals output from a plurality of vibration elements. Thus, for example, the received beam data is collected from the entire area within the fan-shaped scanning region 30.

  The ultrasonic image forming unit 14 forms image data of an ultrasonic image based on the reception beam data formed in the transmission / reception unit 12. For example, image data of a two-dimensional B-mode image corresponding to the scanning region 30 is formed based on reception beam data obtained by two-dimensionally scanning an ultrasonic transmission beam. Of course, image data of a three-dimensional ultrasonic image may be formed based on received beam data obtained by three-dimensionally scanning an ultrasonic transmission beam. Further, image data such as a Doppler image may be formed as the image data.

  The display image forming unit 16 forms a display image based on the ultrasonic image (image data) formed in the ultrasonic image forming unit 14. Further, the display image forming unit 16 forms a display image, a user interface image, and the like corresponding to the apparatus state of the ultrasonic diagnostic apparatus. The display image formed in the display image forming unit 16 is displayed on the display unit 18.

  The operation panel 22 is an operation device that accepts user operations. The operation panel 22 is, for example, a trackball, a mouse, a keyboard, a touch panel, etc.

  The control unit 20 controls each unit in the ultrasonic diagnostic apparatus. For example, the control unit 20 controls each unit in the apparatus in accordance with a user operation input via the operation panel 22. In this embodiment, scanning control of the ultrasonic beam is performed so that the image range, frame rate, and resolution of the ultrasonic image are arranged side by side. In the control, if necessary, an operation is received from the user via, for example, an operation panel 22 provided in the apparatus main body or an operation device (see FIGS. 4 and 5) provided in the probe 10. Therefore, the scanning control of the ultrasonic beam in this embodiment will be described below.

  In this embodiment, scanning is performed by changing the beam interval according to the position of the region of interest. For example, in the scanning region 30, in order to maintain the beam density of the ultrasonic beam relatively densely in the region of interest where the tissue to be diagnosed exists, and to observe the wide scanning region 30, the region of interest In other areas, the beam density of the ultrasonic beam is made relatively coarse.

  FIG. 2 is a diagram for explaining the change of the beam interval according to the position of the region of interest. FIG. 2A shows an example (comparative example) in which the ultrasonic beam is scanned at a constant interval without changing the beam interval in the scanning region 30. On the other hand, in FIG. 2B, the beam interval is relatively narrow in the region of interest located in the center of the scanning region 30, and the beam interval is gradually increased toward the both ends of the scanning region 30 as the distance from the region of interest increases. An example of this case (this embodiment) is shown.

  In the present embodiment, for example, even if the number of ultrasonic beams is the same as in the comparative example, high resolution can be realized because the interval between the ultrasonic beams is narrow at the position of the region of interest, and the number of ultrasonic beams Therefore, the ultrasonic beam can be scanned within the scanning area 30 having the same area as that of the comparative example without reducing the frame rate.

  In the case of the comparative example shown in FIG. 2A, the ultrasonic beam formed in the scanning area 30 is a scanning area (SCAN_AREA) that is the vertex angle of the fan-shaped scanning area 30 (vertex angle θ in FIG. 1). Is divided by the number of beams (BEAM_NUM), the pitch (Pitch), which is the beam interval between the ultrasonic beams, is calculated by the following equation.

  Further, using the pitch, the beam position (BEAM_POS) that is the beam angle of the ultrasonic beam corresponding to each beam number (BEAM_NO) is calculated as follows.

  In the comparative example, since the pitch that is the beam interval is fixed in the scanning region 30, the beam interval is constant throughout the scanning region 30, as shown in FIG.

  On the other hand, in this embodiment, the beam interval of the ultrasonic beam is changed in the scanning region 30 according to the position of the region of interest. That is, a comparative example using a minimum beam interval (minPitch) corresponding to the minimum value of the beam interval, a beam number (BEAM_NO), and a pitch conversion coefficient (Pc) for adjusting the beam interval according to the beam number. The beam interval data (minPitch + (Pc × | BEAM_NO |)) is calculated instead of the fixed pitch (Pitch), and the beam position (BEAM_POS) is calculated as follows using this beam interval data. .

Incidentally, the beam interval data may be (minPitch + (Pc × | BEAM_NO |) ⁿ ) and the beam interval data including the nth power may be used.

  In the equation (3), the pitch conversion coefficient (Pc) is calculated based on the scan end position (END_AREA) that is the beam position of the ultrasonic beam at the end of the scanning region 30 and the ultrasonic beam at the end of the scanning region 30. Based on the scan end beam number (END_BEAM_NO), which is the beam number, and the minimum beam interval (minPitch) corresponding to the minimum value of the beam interval, the following equation is calculated.

  For example, if the scan area (SCAN_AREA) is 60 degrees (-30 to 30 degrees), the scan end position (END_AREA) is 30 degrees, and if the number of beams (BEAM_NUM) is 31 (-15 to 15), the scan end beam When the number (END_BEAM_NO) is 15 and the minimum beam interval (minPitch) is 1 degree, the pitch conversion coefficient is Pc = 0.0666666667 from equation (4). Further, when the beam position (BEAM_POS) in this case is calculated for each beam number from the equation (3), it is as shown in FIG.

  FIG. 3 is a diagram illustrating a correspondence relationship between each beam number (BEAM_NO) and a beam position (BEAM_POS). FIG. 3 shows the beam position of the present embodiment calculated using the above equations (3) and (4) and the beam position of the comparative example calculated using the above equations (1) and (2). It is shown.

  In the comparative example, the beam interval of the ultrasonic beam is constant throughout the scanning region. On the other hand, in the present embodiment, the beam position is relatively narrow near the beam number 0, that is, near the center of the scanning region (reference numeral 30 in FIG. 2), and the beam number increases as the absolute value of the beam number increases. The position interval is wide. In other words, there is a region of interest near the center of the scanning region, the beam density of the ultrasonic beam is relatively dense near the center, and the beam density of the ultrasonic beam gradually increases as the distance from the region of interest near the center increases. .

  As described above, in the present embodiment, the beam density is the same as the number of beams in the comparative example, that is, the same frame rate as in the comparative example can be realized, but the beam density in the region of interest near the center of the scanning region. To achieve high resolution in the region of interest. Furthermore, in the present embodiment, a scanning region having the same size as that of the comparative example can be formed.

  The transmitter / receiver 12 illustrated in FIG. 1 controls the probe 10 so as to form an ultrasonic beam at a beam position calculated using, for example, the above equations (3) and (4). The probe 10 is provided with a user operation device for changing the scanning control mode. And the control part 20 operate | moves according to the user operation received via the user operation device, control information is transmitted from the control part 20 to the transmission / reception part 12, and the control mode of a scan is changed.

  FIG. 4 is a diagram for explaining the user operation device 120 provided in the probe 10. The user operation device 120 is used, for example, when the user changes the pitch conversion coefficient (Pc) and the minimum beam interval (minPitch) in the above equations (3) and (4). The user can perform a change operation while holding the probe 10. Therefore, the user operation device 120 is provided, for example, on the side surface on the distal end side (the ultrasonic wave transmission / reception side) of the probe 10.

  FIG. 4A shows the probe 10 using the electrostatic pad 120A as an operation device. The user slides his / her finger on the surface of the electrostatic pad 120 </ b> A while holding the probe 10. Thereby, for example, the value of the pitch conversion coefficient or the minimum beam interval changes depending on the direction in which the finger slides.

  On the other hand, FIG. 4B shows the probe 10 using the slide lever 120B as an operation device. The user slides the slide lever 120B with a finger. Thereby, for example, the value of the pitch conversion coefficient and the minimum beam interval changes according to the sliding direction of the slide lever 120B. A recess 122 corresponding to the user's finger is provided in the center of the surface of the slide lever 120B, and the user's finger is fitted in the recess 122, thereby facilitating the slide operation.

  FIG. 5 is a diagram for explaining another aspect of the user operation device 120 provided in the probe 10, and shows the probe 10 using a dial 120C as the operation device. The user rotates the dial 120C, and the pitch conversion coefficient and the minimum beam interval change according to the rotation.

  Each of the operation devices shown in FIGS. 4 and 5 is provided with a button function. For example, each time the button is pressed, the minimum beam interval is “narrow, medium, wide, narrow, medium, wide” or “narrow, medium, The size may be changed to “wide, medium, narrow” and the size may be sequentially switched. Further, one of the pitch conversion coefficient and the minimum beam interval is operated by the operation devices shown in FIGS. 4 and 5, and the pitch conversion coefficient and the minimum are controlled by an operation panel (reference numeral 22 in FIG. 1) provided in the apparatus body. The other of the beam intervals may be operated.

  In the above-described example, the beam interval is changed using the equations (3) and (4). However, the beam interval may be changed stepwise. For example, the step coefficient (dk) indicating the number of steps of the beam interval changed stepwise, the scan angle (SCAN_AREA) corresponding to the size of the scan region, and the number of ultrasonic beams formed in the scan region A certain number of beams (BEAM_NUM) may be used, and the pitch (Pitch) that is the beam interval may be changed step by step as S_pitch, M_pitch, and L_pitch as in the following equation.

  For example, when the scanning angle (SCAN_AREA) is 90 degrees (−45 to 45), the number of beams (BEAM_NUM) is 30, and the step coefficient (dk) is 3, S_pitch = 0.97261, M_pitch = 1.956522, and L_pitch = 5.869565. Further, when the beam position (BEAM_POS) in this case is calculated for each beam number, it is as shown in FIG.

  FIG. 6 is a diagram illustrating a correspondence relationship between each beam number (BEAM_NO) and a beam position (BEAM_POS). FIG. 6 also shows the pitch (Pitch), which is stepwise from S # pitch, M_pitch, and L_pitch from beam number 0 in the center of the scanning region to beam numbers -14 and 15 at the end of the scanning region. It has been switched. In the example shown in FIG. 6 as well, for example, it is possible to increase the beam density in the region of interest near the center of the scanning region while maintaining the size of the scanning region, thereby realizing high resolution in the region of interest.

  The transmission / reception unit 12 shown in FIG. 1 corresponds to each of a plurality of beam numbers based on the beam position (for example, BEAM_POS shown in FIGS. 3 and 6) calculated for each beam number using the beam interval data. A parallel reception process is performed in which two transmission beams are made to correspond to one transmission beam by forming one transmission beam between two adjacent reception beams. May be.

  FIG. 7 is a diagram for explaining parallel reception processing in the present embodiment. For example, when the number of transmission beams is 31, the number of reception beams is 62, and the beam position of the reception beam is calculated using the above-described equations (3) and (4). Based on the beam positions of two reception beams RXA and RXB adjacent to each other, the beam position of the transmission beam TX1 is set to “TX1 beam position = (RXA beam position + RXB beam position) / 2”. Similarly, the beam position of the transmission beam TX2 is “TX2 beam position = (RXC beam position + RXD beam position) / 2”. In this way, parallel reception processing in which two transmission beams are associated with one transmission beam may be executed.

  The preferred embodiments of the present invention have been described above. However, according to the above-described embodiments, for example, it is possible to obtain a wide range of information at high speed while maintaining high resolution in the region of interest. In particular, in recent years, an ultrasonic diagnostic apparatus has been used as an operation support apparatus. For example, the ultrasonic diagnostic apparatus of the present embodiment can be used as such an intraoperative support apparatus.

  For example, a two-dimensional or three-dimensional ultrasonic image is formed by the ultrasonic diagnostic apparatus of the present embodiment, and an image when the treatment instrument is inserted into the patient's body is displayed. Immediately after the insertion is started, an ultrasonic beam is scanned at a uniform beam interval in the scanning region to form an image, and when the treatment instrument approaches the affected area, the image is high in the interested area including the affected area. The ultrasonic beam is formed at a density, and the ultrasonic beam is formed at a low density in other areas. Thereby, it is possible to increase the resolution in the region of interest including the affected area while suppressing a decrease in the processing speed of image formation, and it is possible to observe the state of the treatment instrument that has reached the affected area with a high resolution image.

  By the way, the positional relationship between the ultrasonic probe and the tip of the treatment instrument is tracked using an infrared sensor or magnetic sensor, and an ultrasonic beam is formed so that the vicinity of the tip of the treatment instrument is always high density based on the positional information. Such an embodiment is also possible.

  In addition, embodiment mentioned above and its effect are only illustrations in all the points, and do not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof.

1 is a functional block diagram showing an overall configuration of an ultrasonic diagnostic apparatus according to the present invention. It is a figure for demonstrating the change of the beam interval according to the position of a region of interest. It is a figure which shows the correspondence of each beam number and a beam position. It is a figure for demonstrating the user operation device provided in a probe. It is a figure for demonstrating another aspect of a user operation device. It is a figure which shows the correspondence of each beam number and a beam position. It is a figure for demonstrating the parallel reception process in this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Probe, 12 Transmission / reception part, 14 Ultrasonic image formation part, 20 Control part.

Claims (4)

A probe having a plurality of vibration elements for transmitting and receiving ultrasonic waves;
A transmission / reception unit that controls a plurality of vibration elements to scan an ultrasonic beam;
An image forming unit for forming ultrasonic image data based on a reception signal obtained from the scanning region via an ultrasonic beam;
A display unit for displaying an ultrasonic image corresponding to the ultrasonic image data;
Have
The transmission / reception unit scans the ultrasonic beam in the scanning region by sequentially forming an ultrasonic beam corresponding to each of the plurality of beam numbers based on the beam position data calculated for each beam number,
The beam position data is calculated using beam interval data corresponding to the beam interval of the ultrasonic beam that is changed according to the position of the region of interest within the scanning region ,
The beam interval data is calculated using minimum beam interval data corresponding to the minimum value of the beam interval and a pitch conversion coefficient for adjusting the beam interval according to the beam number.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1 ,
The pitch conversion coefficient includes region end position data corresponding to the beam position of the ultrasonic beam at the region end of the scanning region, region end beam number corresponding to the beam number of the ultrasonic beam at the region end of the scanning region, and the minimum Calculated based on the beam interval data,
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1 or 2 ,
The probe includes a user operation device that receives a change operation for at least one of the minimum beam interval data and the pitch conversion coefficient.
An ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to any one of claims 1 to 3 ,
The transmission / reception unit forms reception beams corresponding to each of a plurality of beam numbers based on beam position data calculated for each beam number using the beam interval data, and two adjacent reception beams By performing one transmission beam in the middle of the two, a transmission / reception process in which the two reception beams correspond to the one transmission beam is executed.
An ultrasonic diagnostic apparatus.

Images