JP5924971B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to a technique for dealing with defective elements.

  Ultrasound diagnostic apparatuses are used in the medical field. An ultrasonic diagnostic apparatus generally includes an array transducer composed of a plurality of vibration elements, a transmission beam former, a reception beam former that generates beam data by phasing addition processing for a plurality of reception signals, and a plurality of beam data. A scan converter that generates image data by applying an interpolation process; An ultrasonic beam is formed in the array transducer and scanned electronically. In electronic linear scanning (including electronic convex scanning), the transmission / reception aperture is scanned on the array transducer, and ultrasonic waves are transmitted and received using a plurality of vibration elements in the transmission / reception aperture at each scanning position. Is done. In some cases, the transmission aperture and the reception aperture are set separately.

  Some vibration elements in the array vibrator may become defective elements due to impact or aging deterioration. When a defective element occurs, the element cannot properly transmit ultrasonic waves, and cannot properly receive ultrasonic waves. In the case of a defective element, the level of the received signal output therefrom is lowered, and if the function is completely impaired, only thermal noise is output. In the receive beamformer, for example, 32 received signals output from the receive aperture are added. Therefore, if one defective element is generated, the effect on the beam data is not so great. Degradation is hardly noticeable. However, for example, when several elements are damaged at the same time due to dropping of the probe or the like, and when they are densely packed, image degradation becomes conspicuous. For example, a strip-shaped dark streak occurs on the image. Patent Documents 1 and 2 disclose techniques for dealing with defective elements by determining pass / fail for each vibration element.

JP 2010-172411 A JP 2009-178262 A

  It is ideal to determine pass / fail for each vibration element. However, when doing so, the input / output signals of the individual vibration elements are referred to, which significantly increases the circuit scale. Along with this, determination and handling are also complicated.

  In the case where damage that cannot be ignored occurs in the array transducer, the probe should be essentially replaced. However, in emergency medicine or the like, there may be no such time margin. Even in such a case, it is desired to eliminate and reduce annoying dark stripes when observing an image.

  An object of the present invention is to deal with defective elements with a simple configuration. Alternatively, a defective element is dealt with at a stage after phasing addition.

  The present invention executes a phasing addition process on an array transducer composed of a plurality of transducer elements and a plurality of reception signals output from a reception aperture set on the array transducer, and outputs beam data A phasing addition unit, a determination unit that determines whether or not the plurality of beam data generated by scanning the reception aperture is defective, and a plurality of effective beams other than the defective beam data in the plurality of beam data And an interpolation processing means for generating display frame data by performing an interpolation process using the data.

  According to the above configuration, when one or a plurality of defective elements exist in the array transducer, and the beam data after phasing addition becomes defective (usually, when the level drops), It is determined as defective beam data. In the display frame data generation stage, display frame data is generated by interpolation processing based on a plurality of other effective beam data (excellent beam data) without using defective beam data. Therefore, it is possible to eliminate or reduce annoying black streaks caused by defective beam data on an ultrasonic image (particularly a two-dimensional tomographic image). According to the above configuration, it is not necessary to conduct individual investigations in units of vibrating elements, and it is possible to perform defect determination and defect handling at the later stage of the beamformer, so that it is not necessary to add a complicated configuration while taking advantage of the existing basic configuration. Thus, problems caused by defective elements can be easily solved or reduced. In addition, it is also possible to determine the degree of quality (defectiveness) instead of the quality determination. In this case, the weight given to the beam data may be varied according to the degree of quality (even in this case, it is determined to be defective). Beam data is excluded from the reference). However, since the received signal becomes extremely small in the case of an element breakage, it is sufficient to make a judgment only for pass / fail when it is assumed to deal with it, and it is simpler.

  The interpolation processing means is preferably a scan converter that performs coordinate system conversion (generation of display frame data from received frame data) from a transmission / reception coordinate system to a display coordinate system. In such a configuration, a conversion table for performing the scan conversion process is generated in advance in consideration of the defective beam address specified in advance, that is, under the condition that the defective beam address data is not used. It is used for image generation at the time of ultrasonic diagnosis.

  Preferably, each effective beam data referred to in the interpolation processing is composed of a plurality of effective data arranged in the depth direction, and the interpolation processing means uses the effective data existing around the interpolation pixel on the display frame as a reference. An interpolated pixel value for the interpolated pixel is generated with reference to the group. When generating interpolated pixel values by interpolation processing from received frame data using individual pixels constituting a display frame as interpolated pixels, typically the nearest neighboring pixel group (for example, four neighbors) existing around the interpolated pixel Reference is made to the pixel value of the pixel. Compared with that, the above configuration will be described. Since the defective beam data is excluded from the reference object in the interpolation process, the nearest pixel group except for them is referred to. At that time, the distance from the interpolation pixel to the reference destination changes depending on the number of defective beams generated adjacent to the interpolation pixel. Normally, in the linear interpolation process, the weight changes according to the distance to the reference destination, so that the contribution of the effective data located far away becomes relatively small.

  Desirably, a conversion table generating unit that specifies a defective beam address where the defective beam data is generated by the determination unit during a calibration operation and generates a conversion table for interpolation processing to be given to the interpolation processing unit based on the defective beam address. Is provided. According to this configuration, a conversion table for performing the calibration operation to deal with the defective beam data is created in advance, and an ultrasonic image is generated using the conversion table in the subsequent normal operation. Although it is desirable that the calibration is periodically performed at a predetermined frequency, the calibration may be performed according to a user instruction or during ultrasonic diagnosis.

  Preferably, at the time of the calibration operation, an identifier recognition unit that recognizes a probe identifier of a connected probe, a storage unit that stores the generated conversion table in association with the probe identifier, and the calibration Control means for reading a specific conversion table associated with the probe identifier of the connected probe from the storage means and supplying it to the interpolation processing means during normal operation after the operation. According to this configuration, the conversion table corresponding to the newly connected probe can be used immediately without performing calibration at the time of probe replacement.

  According to the present invention, it is possible to deal with defective elements with a simple configuration. Alternatively, it is possible to deal with a defective element at a stage after phasing addition.

1 is a block diagram showing a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention. It is a figure for demonstrating formation of a defective beam. It is a figure which shows the ultrasonic image which has the black stripe | line equivalent to a bad beam. It is a figure for demonstrating the interpolation process in the place which excluded bad beam data. It is a figure which shows the ultrasonic image after an interpolation process. 3 is a flowchart illustrating an operation example of the apparatus illustrated in FIG. 1. It is a figure for demonstrating the operation mode at the time of the normal operation | movement after calibration.

  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 block diagram showing the overall configuration thereof. This ultrasonic diagnostic apparatus is used in the medical field and forms an ultrasonic image by transmitting / receiving ultrasonic waves to / from a living body.

  In FIG. 1, a probe 10 is a transducer that transmits and receives an ultrasonic wave, and the probe 10 is used in contact with a body surface, for example. The probe 10 has a 1D array transducer 12 in this embodiment. The 1D array transducer 12 includes a plurality of vibrating elements 12a arranged in a straight line. An ultrasonic beam is formed by the array transducer 12, and the ultrasonic beam is electronically scanned. As the electronic scanning method, electronic linear scanning, electronic sector scanning, and the like are known.

  The probe 10 is attached to and detached from the apparatus main body, and a memory 14 is provided inside the probe head or probe connector of the probe 10. A probe ID indicating the identifier of the probe 10 is stored in the memory 14. Of course, a technique for expressing a probe code depending on whether or not a plurality of pins are connected may be employed.

  The transmission unit 16 is a transmission beamformer, and a plurality of transmission signals are supplied in parallel from the transmission unit 16 to the array transducer 12 at the time of transmission. As a result, a transmission beam is formed. The reflected wave from the living body is received by the array transducer 12, and a plurality of received signals are output to the receiving unit 18. The reception unit 18 is a reception beam former (DBF), and generates beam data by phasing addition processing for a plurality of reception signals. The beam data corresponds to one ultrasonic beam. As will be described later, in the present embodiment, the operation mode includes a calibration operation and a normal operation, and the transmission unit 16 and the reception unit 18 perform the operation according to each operation mode. In the calibration operation, the probe is left in the air, and at that time, a plurality of transmission signals are supplied with full power to the transmission aperture, and a plurality of reception signals output from the same reception aperture as the transmission aperture are received. The phasing addition process is executed. Such a calibration operation is premised on electronic linear scanning (including convex scanning). That is, calibration transmission / reception is repeatedly executed while the transmission aperture and the reception aperture are electronically scanned.

  The beam data output from the receiving unit 18 is output to the signal processing unit 20. The beam data is also output to the cine memory 24. The cine memory 24 has a ring buffer structure, and outputs beam data in time-series order by a user operation after freezing. The signal processing unit 20 includes various circuits such as a detection circuit and a logarithmic conversion circuit in the present embodiment, and includes a pass / fail determination unit 22 in the present embodiment.

  The pass / fail judgment unit 22 functions during the calibration operation and has a function of judging pass / fail of the beam data for each beam data. For example, when a transmission / reception aperture is set at a certain position on the array transducer and the amplitude or power of the beam data after phasing addition obtained from the transmission / reception aperture is extremely small, the pass / fail judgment unit 22 converts the beam data into a defective beam. Judge as data. The other data is determined as effective beam data (excellent beam data). For example, when one or more defective elements exist in the transmission / reception opening, the level of the beam data is lowered. Therefore, the pass / fail judgment unit 22 indirectly determines the presence of the defective element. It can be said that. The determination result of the pass / fail determination unit 22 is output to the control unit 34.

  A digital scan converter (DSC) 26 converts received frame data according to the transmission / reception coordinate system into display frame data according to the display coordinate system. It has a coordinate conversion function and an interpolation function. The reception frame data is composed of a plurality of beam data corresponding to a plurality of beams constituting one scanning plane. The display frame data is composed of a plurality of horizontal line data. In the DSC 26, specifically, display pixel addresses are sequentially generated in accordance with raster scanning, and a reception address data set for interpolation processing corresponding to each display address is generated. Based on the interpolation processing, an interpolation value is generated. In this case, the interpolation table 28 is used. That is, the interpolation table 28 converts the display address into a reception data address set, and the reception data address set is the four nearest receptions existing around the pixel of interest in the present embodiment, excluding the defective beam data. It specifies the address of data.

  In this embodiment, the interpolation table 28 is generated during the calibration operation, and individual display frames are generated from individual received frames during normal operation using the interpolation table generated in advance. Has been. The display frame constitutes a tomographic image.

  The display processing unit 30 has an image composition function and the like, and image data is output from the display processing unit 30 to the display unit 32. A tomographic image as a B-mode image is displayed on the display unit 32.

  The control unit 34 controls the operation of each component shown in FIG. 1. In the present embodiment, the control unit 34 controls each component particularly during the calibration operation and the normal operation. During the calibration operation, the aperture position is sequentially set on the array transducer and transmission is performed with the full power using the aperture, and the received signals from a plurality of elements in the aperture are received within a certain period thereafter. Observed. During the calibration operation, the transmission delay and the reception delay need not be performed specially. Of course, the transmission focus may be set to a predetermined depth, and the reception focus may be set dynamically. Such transmission / reception is performed at each aperture position, that is, calibration beam data is obtained for each beam address. This beam data is an output signal of the DBF 18. Details of the operation during the calibration operation will be described later with reference to FIG.

  An operation panel 36 is connected to the control unit 34. The operation panel 36 has a keyboard, a trackball, and the like. The control unit 34 includes a memory (not shown), and an interpolation table associated with the probe ID, that is, a conversion table for interpolation processing, is stored in the memory. The control unit 34 also has a function of generating a graphic image. In the display processing unit 30, the graphic image is synthesized on the ultrasonic image, and image data as a result of the synthesis is output to the display unit 32.

  Incidentally, when referring to each beam data in the pass / fail judgment unit 22 during the calibration operation, all of the received signal power within a certain depth range may be referred to, or only the power of a predetermined depth may be referred to. May be referred to. In any case, it is desirable to refer to the defective element so that it can be determined.

  As described above, when an interpolation table is generated as a result of calibration transmission / reception during the calibration operation, a tomographic image is generated using the interpolation table during the subsequent normal operation. . In this embodiment, as described above, the probe ID of the probe connected to the apparatus main body is automatically read, and an interpolation table is stored in association with the probe ID. Therefore, when probe replacement occurs, it is possible to automatically identify the most suitable interpolation table for the probe by reading the probe ID of the newly connected probe and use it to immediately generate an ultrasound image. It is.

  FIG. 2 conceptually shows the electronic linear scanning of the ultrasonic beam. The probe 10 has the array transducer 12 as described above, and the array transducer 12 is composed of a plurality of transducer elements. Here, reference numerals 38, 40, and 42 among the plurality of vibration elements indicate defective elements, and the degree of defect of the element 40 is particularly large. When a transmission / reception aperture 44 is set on the array transducer 12 and a transmission beam and a reception beam are formed using the transmission / reception aperture 44, an ultrasonic beam 46 as a transmission / reception integrated beam is generated. When the same transmission / reception is repeatedly performed while shifting the position of the transmission / reception aperture 44 in units of elements, a plurality of ultrasonic beams are formed along the element arrangement direction of the array transducer, and a plurality of beam data corresponding thereto. Will be obtained. At this time, if the defective elements 38, 40, 42 are included in the transmission / reception opening 44, the larger the number of defective elements, the lower the power of the beam data.

  As a result, the phenomenon shown in FIG. 3 occurs. That is, a tomographic image 50 is displayed on the display screen 48, and black streaks 52 are generated there. This is caused by a defective element, and has been expressed relatively black because the level of the beam data is low. Since a plurality of received signals are added in the phasing addition process, for example, if there are about one defective element, black streaks are hardly noticeable, or if a plurality of defective elements are formed side by side, for example, Even after the addition, a level down due to the number of defective elements occurs, and as a result, black streaks 52 as shown in FIG. 3 occur. Such black streaks 52 hinder image observation. In the present embodiment, the generation of the black streak 52 can be prevented or reduced by generating a unique interpolation table by the calibration operation.

  A countermeasure against the defective element will be specifically described with reference to FIG. Incidentally, FIG. 4 shows a case where a plurality of ultrasonic beams extending in a fan shape are formed for the purpose of explaining the invention. Of course, electronic linear scanning that forms a plurality of ultrasonic beams in parallel with each other may be applied.

  Reference numeral 46A indicates effective beam data, and reference numeral 46B indicates defective beam data. The effective beam data 46A is composed of a plurality of effective data 54 arranged in the depth direction, and each piece of data is indicated by a white circle. The defect beam data 46B is composed of a plurality of defect data arranged in the depth direction, and in the present embodiment, these defect data are not used as reference objects for interpolation processing. That is, when the defective beam data is excluded, four nearest neighbor data existing around the target pixel are specified, and interpolation data is generated based on them. Specifically, in the display pixel matrix 56, each point in the grid corresponds to a display pixel, and a pixel value is determined by interpolation processing from four effective data existing around each display pixel. That is, the interpolation value generated by the interpolation process is set as the pixel value of the pixel. At that time, it is conditioned so that the reference on the defective beam data is not performed. For example, for the pixel 58, the nearest neighbor data on the effective beam data beyond the defective beam data 46 is referred to and weighted by them. Interpolated values are generated by linear interpolation processing. Similarly, in the pixels 60 and 62, the defective beam data is excluded from the reference destination, and four data constituting the effective beam data are referred to. Therefore, when defective beam data is connected, the distance from the target pixel to the reference destination becomes longer. In view of image quality, it should be avoided that the distance becomes long. However, in the present embodiment, priority is given to prevention of black streaks and a reference destination is secured. However, since the smaller weight value is given as the distance becomes longer, the closer effective data contributes more greatly.

  Therefore, under the above interpolation processing conditions, specifically, an ultrasonic image 64 as shown in FIG. 5 can be generated by using an interpolation table that satisfies such conditions. That is, as indicated by reference numeral 66, the black streak is inconspicuous, that is, the black streak can be substantially eliminated or effectively reduced. In this case, the interpolated portion may be specified by the marker 68, for example. In that case, the center of the defective beam data area may be indicated, or the range thereof may be indicated. In any case, the user can perceive a portion or a range to which a special interpolation process is applied for image observation, so that convenience in image diagnosis can be achieved.

  FIG. 6 shows the operation of the apparatus shown in FIG. 1 as a flowchart, and particularly shows the calibration operation. The calibration operation can be executed periodically, or can be executed by a user instruction. It is desirable to perform calibration for each connectable probe in advance and register an interpolation table in advance. According to such a configuration, it is possible to read out a necessary interpolation table and use it immediately after the probe is connected.

  In S100, the currently connected probe ID is recognized. In the embodiment described above, information in the memory provided in the probe is referred to. However, the probe ID may be registered by the user. In S102, a transmission / reception opening is set at a predetermined opening position, and transmission using the transmission / reception opening, that is, block transmission is executed. In this case, it is desirable to perform transmission at full power, and transmission delay may or may not be applied.

  In S104, reception processing is executed in the transmission / reception opening. That is, block reception is executed. The reception delay may or may not be applied at the time of reception. However, it is necessary to operate the DBF so that an output after phasing addition is generated.

  In the present embodiment, the block transmission and the block reception as described above are performed after the probe is left in the air. In S106, the level of the beam data obtained by the transmission / reception is determined. For example, a predetermined depth value in the beam data is referred to, or a power integrated value within a predetermined depth range is referred to, and these are compared with a predetermined threshold value to determine whether the beam data is defective or good. become. For example, when a certain number of defective elements are included in the transmission / reception aperture, the beam data is determined to be defective. In this case, the address of the defective beam is specified in S108 and stored in the memory. In S110, it is determined whether or not calibration transmission / reception has been executed at all transmission / reception aperture positions. If all have not been completed, the transmission / reception aperture position is shifted by one in S112, and each step after S102 is repeated. Executed. It is also possible to set the transmission aperture and the reception aperture with different sizes. It is desirable that calibration transmission / reception be executed under the same transmission / reception conditions as in normal diagnosis.

  In S114, an interpolation table is generated based on the defective beam address stored in the memory. That is, as described with reference to FIG. 4, a table for interpolation processing is generated under the condition that the defective beam data is not used. In S116, the interpolation table thus generated is stored on the memory. In that case, storage is performed in association with the probe ID. The above operation is executed for each connectable probe as necessary.

  Therefore, when a normal diagnosis operation is performed after performing calibration, an optimum interpolation table is read according to the ID of the connected probe and registered in the DSC 26. Therefore, if ultrasonic waves are transmitted and received using such an interpolation table, the defective beam is automatically excluded and the interpolation process is performed. As a result, the influence of the defective beam data is minimized. Ultrasonic images can be displayed. That is, it is possible to display on the screen an ultrasonic image in which black stripes are not generated or inconspicuous. In that case, the control unit 34 generates a graphic image including a marker based on the defective beam data address, and such an image is displayed as an overlay on the ultrasonic image.

  FIG. 7 shows an operation mode during normal operation. Each operation mode represents a specific operation content corresponding to the defective beam address 206. In the first operation mode 202, a normal operation is performed on the defective beam address 200 during transmission, and a normal operation is performed during reception. However, as described above, the defective beam data is invalidated in the conversion process, that is, the interpolation process is applied as a countermeasure for the defect. In the second operation mode 204, the power is turned off for the defective beam address 200 at the time of transmission, that is, transmission is not substantially performed. At the time of reception, the beam data corresponding to the defective beam address 200 is acquired as usual, and is invalidated because it is excluded from the conversion processing target. Even in this case, a countermeasure by the interpolation process is executed for the defective beam address. In the third operation mode 206, the defective beam address 200 is skipped during transmission and skipped during reception. That is, both the transmission action and the reception action for the defective beam address 200 are omitted, and the transmission / reception frame rate is increased accordingly. In the digital scan converter, interpolation data is generated by high-speed processing, that is, necessary interpolation values are generated by interpolation processing using an interpolation table as described above.

  As described above, in this embodiment, since a defective beam address can be specified in advance by calibration transmission / reception, normal transmission / reception operation conditions are appropriately determined on the assumption that a conversion table suitable for the address is used. Is possible.

  10 probe, 12 array transducer, 20 signal processing unit, 22 pass / fail judgment unit, 28 interpolation table.

Claims (4)

An array vibrator comprising a plurality of vibration elements;
A phasing addition unit that performs phasing addition processing on a plurality of reception signals output from the reception aperture set on the array transducer and outputs beam data;
Determination means for determining whether or not the plurality of beam data generated by scanning the reception aperture is defective;
Interpolation processing means for generating display frame data by performing interpolation processing using a plurality of effective beam data other than defective beam data in the plurality of beam data;
Only including,
Conversion table generation means for generating a conversion table for interpolation processing to be given to the interpolation processing means based on a defective beam address where the defective beam data occurs is provided,
The interpolation processing conversion table is a conversion table for the interpolation processing for generating the display frame data from reception frame data including a plurality of effective beam data other than the defective beam data.
An ultrasonic diagnostic apparatus. The apparatus of claim 1.
The defective beam address the defective beam data is generated by said judging means during the calibration operation is specified,
An ultrasonic diagnostic apparatus. The apparatus of claim 2 .
During the calibration operation, the probe including the array transducer is left in the air,
An ultrasonic diagnostic apparatus. The apparatus of claim 2 .
Identifier recognition means for recognizing the probe identifier of the connected probe during the calibration operation;
Storage means for storing the generated conversion table in association with the probe identifier;
Control means for reading a specific conversion table associated with a probe identifier of a connected probe from the storage means and providing it to the interpolation processing means in a normal operation after the calibration operation;
An ultrasonic diagnostic apparatus comprising: