JP5209184B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus, and in particular, by calculating the strain and / or elasticity of a point corresponding to each coordinate of a tomographic image obtained using ultrasonic waves, the hardness or softness of a living tissue is calculated. The present invention relates to an ultrasonic diagnostic apparatus capable of obtaining an elastic image shown.

  The ultrasonic diagnostic apparatus irradiates an ultrasonic probe while scanning an ultrasonic beam from an ultrasonic probe used in contact with the subject, and sequentially detects reflected ultrasonic waves in the process. A tomographic image made up of, for example, a B-mode image is obtained by imaging the reflection intensity at each position on the scan plane.

  In addition to a tomographic image, an elastic image is displayed by being juxtaposed with or superposed on the tomographic image, and a device capable of recognizing the degree of hardness or softness of a living tissue at a location corresponding to the tomographic image is known. It is like that.

  Here, the elasticity image is obtained by applying a pressure (increase / decrease) to the subject and using the correlation calculation of the ultrasonic reception signals of two frames adjacent in time series obtained in the process. It is constructed by calculating an elastic modulus corresponding to the pressure value based on the displacement calculation.

Such an ultrasonic diagnostic apparatus is disclosed in detail in, for example, Patent Document 1 or Patent Document 2 below.
JP-A-5-317313 JP 2000-60853 A

  However, when the ultrasonic diagnostic apparatus includes a tissue that is displaced at a high speed in the time interval between the ultrasonic reception signals of two frames adjacent in time series, the displacement calculation range of the tissue deviates. There may be an error (correlation calculation error) area where displacement cannot be calculated correctly.

  For example, when an elastic image of a tissue surrounded by blood, which is a fluid that moves at high speed around a thrombus or plaque in a blood vessel, is constructed, the above-described error region is marked and a high-quality elastic image cannot be obtained. Inconvenience may occur.

  An object of the present invention is to provide an ultrasonic diagnostic apparatus capable of avoiding the display of a correlation calculation error region as described above and obtaining a high-quality elastic image.

   Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

(1) The ultrasonic diagnostic apparatus according to the present invention calculates , for example, the displacement of a measurement point on a tomographic image, and generates an elastic image generation unit that generates an elastic image indicating the hardness or softness of a living tissue based on the displacement. An ultrasonic diagnostic apparatus comprising: a velocity distribution detection unit that obtains velocity information of a specific region by a Doppler method, and selects an image region based on the velocity information; and an image region selected by the velocity distribution detection unit And an elastic image selection means for selecting an elastic image corresponding to.

(2) The ultrasonic diagnostic apparatus according to the present invention is based on, for example, the configuration of (1), and the elastic image information selected by the elastic image selecting means gives hue or luminance information, and the elastic image not selected. The area corresponding to the information is provided with means for giving the speed information .

(3) The ultrasonic diagnostic apparatus according to the present invention includes, for example, a pulsation signal processing unit that calculates the amount of displacement of a portion displaced by pulsation and performs correction to restore the displacement based on the configuration of (1). And an elastic image is generated by the elastic image generating means based on information from the pulsation signal processing unit.

(4) The ultrasonic diagnostic apparatus according to the present invention is premised on the configuration of (1), for example, the velocity distribution detecting means compares the threshold value obtained in advance with the velocity information , and the elastic image selecting means is The elastic image does not display a region where the velocity information is larger than the threshold value.

  In addition, this invention is not limited to the above structure, A various change is possible in the range which does not deviate from the technical idea of this invention.

  According to the ultrasonic diagnostic apparatus having such a configuration, a high-quality elastic image can be displayed.

  Embodiments of an ultrasonic diagnostic apparatus according to the present invention will be described below with reference to the drawings.

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

  First, there is an ultrasonic probe 1 used in contact with a subject (not shown). The ultrasonic probe 1 is configured to include a large number of ultrasonic transducers arranged in parallel on the contact surface side with the subject.

  In addition, the ultrasonic probe 1 irradiates ultrasonic waves into the subject by performing ultrasonic beam scanning of the ultrasonic transducers in a plane including the ultrasonic transducers, for example. An ultrasonic wave reflected in the subject is received. Here, the surface (scanning surface) on which ultrasonic beam scanning is performed corresponds to the surface in the tomographic image of the subject to be obtained.

  In this embodiment, the contact of the ultrasonic probe 1 with the subject is operated so as to press the subject and cause displacement. This is because it is necessary to calculate a displacement from tomographic images on at least two scan planes that are temporally different and generate an elastic image based on the displacement.

  Irradiation of ultrasonic waves by the ultrasonic probe 1 is performed by driving the transmission circuit 2, and reception of reflected ultrasonic waves is performed by driving the reception circuit 3. The timings of driving the transmission circuit 2 and the reception circuit 3 are ultrasonic waves. It is controlled by the transmission / reception control circuit 4.

  The transmission circuit 2 includes a transmission phasing / adding circuit (not shown), and the convergence point of the ultrasonic wave transmitted by the transmission phasing / adding circuit can be set to a certain depth. .

  Ultrasound reflected in the subject (ultrasound from the beam scanning surface of the ultrasound transducer) is input to the receiving circuit 3 as a reflected echo signal via the ultrasound probe 1, and further, a phasing addition circuit. 5 is output. In the phasing addition circuit 5, the phase of the reflected echo signal is controlled to form an ultrasonic beam at one point or a plurality of convergence points.

  The reflected echo signal (RF signal) from the phasing / adding circuit 5 whose phase is controlled is input to the signal processing unit 6, where the reflected echo signal is A / D converted, Processing such as gain correction, log compression, detection, and ring enhancement is performed.

  A plurality of tomographic image data (for example, B-mode image data) continuously output in time series from the signal processing unit 6 is stored in each frame memory by the black-and-white scan converter 7, respectively, and in a television system cycle. It is designed to be read out.

  The tomographic image data from the black and white scan converter 7 is output to the image display 9 through the switching adder 8 so that the black and white tomographic image is displayed on the screen.

  Here, the switching adder 8 is configured to receive color tomographic image data from a color scan converter 13 (to be described later) together with the tomographic image data from the monochrome scan converter 7, and an operation via the control unit 16. By operating the console 15, the images are added (superimposed), arranged in parallel, or switched to be output to the image display 9.

  On the other hand, the reflected echo signal (RF signal) from the phasing addition circuit 5 is input to the RF signal frame data selection unit 10, and the RF signal corresponds to the scan plane in the RF signal frame data selection unit 10. Each frame is sequentially stored in the frame memory.

  Here, when each of the frame memories stores the currently stored RF signal frame data as the frame data N, the frame data (N−1), frame data (N−2), frame data ( N-3), ..., frame data (NM) exists. Then, the frame data other than the frame data N (N-1), (N-2), (N-3),... And a set of frame data composed of the frame data N and the frame data X is output to the displacement measuring unit 11. Here, the selection of the frame data X is made based on a selection command from the console 17 via the control unit 16, for example.

Data from the RF signal frame data selection unit 10 is input to the displacement measurement unit 11, which is based on a set of RF signal frame data sequentially output from the RF signal frame data selection unit 10. Dimensional or two-dimensional correlation processing is executed, the displacement or movement vector (direction and magnitude of displacement) of each measurement point on the tomographic image is measured, and displacement frame data is generated. As a method for detecting the movement vector, for example, a block matching method can be used as described in JP-A-5-317313. In this block matching method, an image is divided into blocks of, for example, N × N pixels, a block closest to the block of interest in the current frame is searched from the previous frame, and a prediction code is referred to this It is a thing to do.
The displacement frame data generated by the displacement measuring unit 11 is input to the strain amount and elastic modulus calculation circuit 12, and the distortion amount and elastic modulus calculation circuit 12 generates elastic frame data EFD.

  In this case, although not shown, for example, a pressure sensor is disposed on the surface of the ultrasonic probe 1 that contacts the subject, and data relating to the pressure at the time corresponding to the generation of the displacement frame data is the distortion. The data relating to the pressure is used in the generation from the displacement frame to the elastic frame data EFD, which is input to the quantity and elastic modulus calculation circuit 12.

  Note that the data relating to the pressure is not necessarily obtained from the pressure sensor arranged on the ultrasonic probe 1 as described above. For example, the data on the contact surface of the ultrasonic probe 1 with the subject is used. A pressure measurement deformable body is attached, and the pressure measurement deformable body and the cover are coated using the RF frame signal output from the RF signal frame data selection unit 10 or the tomographic image data output from the monochrome scan converter 7. The pressure distribution at the boundary of the specimen may be calculated according to the degree of deformation of the pressure measuring deformable body, and the calculation result may be used as pressure data. The degree of deformation of the pressure measurement deformable body is based on the fact that, for example, the ultrasonic wave transmitted through the pressure measurement deformable body has a smaller amplitude than the ultrasonic wave transmitted through the subject. It can be calculated by measuring the distance passing through the measurement deformable body.

  Here, each data Ymi, j in the elastic frame data EFD is represented by the following equation (1). Here, the indices i and j indicate the coordinates of the elastic frame data.

Ymi, j = pressure i, j / strain amount i, j (i, j = 1, 2, 3,...)
...... (1)
Note that the strain amount distribution (εi, j) is obtained by performing spatial differentiation (ΔLi, j / Xi, j) of the displacement distribution.

  The strain and elastic modulus calculation circuit 12 performs various image processing such as smoothing processing in the coordinate plane, contrast optimization processing, smoothing processing in the direction of the time axis direction between frames on the elastic frame data EFD, The frame data subjected to such image processing may be output as elastic frame data.

  The RF signal from the phasing addition circuit 5 is input to the velocity distribution detection circuit 14. The velocity distribution detection circuit 14 is configured as a circuit for obtaining the velocity of a specific area from the RF signal, a so-called pulse Doppler circuit, or a so-called color flow mapping circuit for calculating a tomographic image of velocity distribution.

  The velocity distribution detection circuit 14 may generate velocity frame data VFD by a velocity measurement method that does not use the Doppler method.

  The velocity distribution detection circuit 14 generates velocity frame data VFD from the velocity at each measurement point on the tomogram, determines the magnitude relationship with the signal Vth input from the console 15 via the control unit 16, and evaluates the velocity. It is output as frame data EEFD.

  If the velocity data of the coordinates (i, j) in the velocity frame data VFD is Vi, j and the velocity evaluation data of the coordinates (i, j) in the velocity evaluation frame data VAFD is Xi, j, Vi, j is a threshold value. When it is larger than Vth, “0” is set to Xi, j of the same coordinate in the velocity evaluation frame data VAFD, and when Vi, j is smaller than the threshold value Vth, Xi, j of the same coordinate in the velocity evaluation frame data. Is set to “1”.

  That is, the speed evaluation data Xi, j on the speed evaluation frame data VAFD is generated under the following conditions (2) and (3) with respect to the speed data Vi, j on the speed frame data VFD.

If speed data Vi, j> threshold value Vth,
Speed evaluation data Xi, j = 0 (i, j = 1, 2, 3,...)
(2)
If velocity data Vi, j <threshold value Vth,
Speed evaluation data Xi, j = 1 (i, j = 1, 2, 3,...)
(3)
The speed evaluation frame data VAFD generated in this way is output to the color scan converter 13.

  As shown in FIG. 2, the color scan converter 13 includes a gradation circuit 13A and a hue conversion circuit 13B.

  The gradation circuit 13A receives the elastic frame data EFD from the strain amount and elastic modulus calculation circuit 12 and the velocity evaluation frame data VAFD from the velocity distribution detection circuit 14, respectively. The elastic frame data EFD and velocity evaluation frame data are input to the gradation circuit 13A. Elastic gradation data EEFD is generated from VAFD.

  That is, the data of each coordinate in the elastic frame data EFD is not gradationized when the corresponding coordinate data on the velocity evaluation frame data VAFD is “0”, and the coordinate is the velocity evaluation. When the data of the corresponding coordinates on the frame data VAFD is “1”, the data is converted into gradations, for example, in 255 levels according to the magnitude of the value of the data, and the elastic gradation data EEFD is generated.

  That is, the elastic gradation data Si, j on the elastic gradation frame data EEFD is generated under the following conditions (4) and (5) with respect to the velocity evaluation data Xi, j on the velocity evaluation frame data VAFD. Is done.

If the speed evaluation data Xi, j = 1,
Elastic gradation data Si, j = value of “1” to “255” depending on the magnitude of the elastic data Ymi, j (4)
(I, j = 1, 2, 3, ...)
If speed evaluation data Xi, j = 0,
Elastic gradation data Si, j = 0 (5)
(I, j = 1, 2, 3, ...)
In other words, the elastic gradation frame data EEFD is obtained by removing (rejecting) the data of the coordinates corresponding to the coordinates where the velocity evaluation frame data VAFD is “0” from the elastic frame data EFD. The data at the coordinates is generated with gradation.

  The hue conversion circuit 13B operates so as to give hue information such as red, green, and blue as elastic image data based on the elastic gradation frame data EEFD. For example, for a region where a large strain is measured, the region is converted into a red code in the elastic image data. Conversely, for a region where a small strain is measured, the region is converted into a blue code in the elastic image data. It has become.

  The elastic image data configured in this way is output to the image display 9 via the switching adder 8, and the elastic image is displayed on the screen. In this case, as described above, it can be added (superimposed), paralleled, or switched and displayed together with the tomographic image by operating the console 15 via the control unit 16.

  FIG. 3 is an explanatory diagram showing the relationship among the velocity frame data VFD, velocity evaluation frame data VAFD, elasticity frame data EFD, and elasticity gradation frame data EEFD in the operation of the ultrasonic diagnostic layer described above.

  First, the velocity frame data VFD is generated based on the signal from the phasing addition circuit 5 in the velocity distribution detection circuit 14, and is stored in the velocity frame memory vfm as shown in FIG. Speed data Vi, j is stored at each coordinate (i, j) corresponding to the data.

  The speed distribution detection circuit 14 further generates speed evaluation frame data VAFD based on the speed frame data VFD. At this time, the operator inputs data corresponding to the speed threshold value by the console 15, and the data is input to the speed distribution detection circuit 14 via the control unit 16. The velocity data Vi, j at each coordinate (i, j) of the velocity frame data VFD is compared with the threshold value. If the velocity data Vi, j is larger than the threshold value, the velocity evaluation frame memory vafm “0” is recorded as the velocity evaluation data Xi, j at the corresponding coordinate (i, j), and when the velocity data Vi, j is smaller than the threshold value, the corresponding coordinate (i, j) of the velocity evaluation frame memory is recorded. “1” is recorded as the speed evaluation data Xi, j in j), thereby generating speed evaluation frame data VAFD.

  On the other hand, the elastic frame data EFD is generated in the strain amount and elastic modulus calculation circuit 12 based on a signal from the displacement measuring unit 11 and data corresponding to a pressure (not shown). The elastic frame data EFD is stored in the elastic frame memory efm, and elastic data Ymi, j is stored at each coordinate (i, j) corresponding to the image data.

  The elastic frame data EFD and the velocity evaluation frame data VAFD are input to a gradation circuit 13A in the color scan converter 13, and the gradation circuit 13A generates elastic gradation frame data EEFD. That is, the gradation circuit 13A sequentially reads the elasticity data Ymi, j at each coordinate (i, j) of the elasticity frame data EFD, and at that time, the corresponding coordinates (i, j) in the velocity evaluation frame data VAFD. Also read the speed evaluation data Xi, j. When the speed evaluation data Xi, j is “0”, “0” is recorded as the elastic gradation data Si, j at the corresponding coordinates (i, j) of the elastic gradation frame memory eefm. . If the speed evaluation data Xi, j is “1”, the elasticity data Ymi, j is stored as the elasticity gradation data Si, j in the corresponding coordinates (i, j) of the elasticity gradation frame memory eefm. The value assigned to “1” to “255” according to the value of j is recorded.

  The elastic gradation frame data EEFD generated in this way is input to a hue conversion circuit 13B in the color scan converter 13, and each hue (i, The elastic gradation data Si, j in j) is converted into a hue corresponding to the value to generate elastic image frame data.

  The ultrasonic diagnostic apparatus configured in this way can avoid displaying an error area where the displacement cannot be calculated correctly, even when a tissue that is displaced at a high speed is included, and has high quality elasticity. An image can be obtained.

  In the above-described embodiment, as shown in FIG. 3D, the elastic gradation frame data EEFD including an area not displayed as an elastic image (an area storing a value of “0”) is formed. An elastic image based on the frame data is displayed on the image display 9. For this reason, the area not displayed as an elastic image is displayed as no information is given. However, the present invention is not limited to this, and for example, displacement speed information is given in an area that is not displayed as an elastic image of the elastic gradation frame data EEFD (an area in which a value of “0” is stored). You may make it comprise. Specifically, for example, information on the region corresponding to the velocity frame data VFD shown in FIG. 3A is stored in the region of the elastic gradation frame data EEFD (region storing the value of “0”). May be stored, and hue or luminance information may be given by the color scan converter 13 based on the stored information.

  FIG. 4 is a block diagram showing another embodiment of the ultrasonic diagnostic apparatus according to the present invention and corresponds to FIG.

  A configuration different from the case of FIG. 1 is that a pulsation signal processing unit 17 is provided between the displacement measurement unit 11 and the strain amount and elastic modulus calculation unit 12.

  The pulsation signal processing unit 17 corrects the displacement caused by the pulsation in the data from the displacement measuring unit 11 so as to return to the original state, and distorts it as data of the displacement produced only by the compression of the ultrasonic probe 1. The quantity and elastic modulus calculation unit 12 is made to output.

  As shown in FIG. 5, the detailed configuration of the pulsation signal processing unit 17 is displayed on the screen by operating the console 15 on, for example, an arterial tube wall of an ultrasonic tomographic image displayed on the image display 9. A coordinate specifying unit 17A formed by performing a setting operation with the pointers overlapped, a displacement amount calculating unit 17B for calculating a displacement amount of a pulsation site (arterial vessel wall) specified by the coordinate specifying unit 17A, Based on the displacement amount of the artery wall of the artery calculated by the displacement amount calculation unit 17B, the displacement correction unit 17C corrects the position of the artery wall of the artery to return to the original position.

  FIG. 6 shows an ultrasonic tomogram displayed on the image display 9, and an artery ART and a vein VEN are displayed on the ultrasonic tomogram.

  Further, this ultrasonic tomographic image changes in time series due to the pulsation of the arterial ART. FIG. 6A shows an image in the previous frame, and FIG. 6B shows an image in the subsequent frame. Yes.

  Due to the pulsation, the tube walls W1 and W2 of the artery ART are displaced outward from the state shown in FIG. 6A by Δd1 and Δd2, respectively, as shown in FIG. 6B. In this case, since the ultrasound P is applied to the ultrasonic tomogram by the ultrasonic probe 1 in contact with the body surface, in the vein VEN on the body surface side with respect to the artery ART, It can be seen that the tube wall w1 is hardly displaced, whereas the opposite tube wall w2 is displaced in accordance with the displacement of the artery wall W1.

  However, such a displacement of the vein VEN is based on the pulsation of the artery ART and the compression P by the ultrasonic probe 1, and the ultrasonic diagnostic apparatus according to the embodiment shown in FIG. Cannot be obtained.

  Therefore, the ultrasonic diagnostic apparatus according to the embodiment shown in FIG. 4 takes out only the displacement of the vein VEN based on the compression P by the ultrasonic probe 1 by newly providing the pulsation signal processing unit 17. The elasticity data of the vein VEN can be obtained.

  FIG. 7 shows an ultrasonic tomographic image displayed on the image display 9 in the ultrasonic diagnostic apparatus of the embodiment shown in FIG. 4, and the ultrasonic tomographic image shows an artery ART as in the case of FIG. And vein VEN are displayed.

  FIG. 7A is a diagram corresponding to FIG. 6A. Unlike FIG. 6A, FIG. 7A is displayed on the screen by operation on the console 15 along the vessel walls W1 and W2 of the artery ART. Marking m1 and m2 displayed by performing a setting operation with the pointers displayed on the screen overlapped.

  The markings m1 and m2 are made by driving the coordinate specifying unit 17A, whereby the pulsation signal processing unit 17 recognizes the position coordinates of the vessel walls W1 and W2 of the artery ART.

  Even if the position coordinates of the tube walls W1 and W2 of the arterial ART are displaced by the pulsation of the arterial ART, the position coordinates are detected, for example, by tracking pixels having the same luminance. In this case, as shown in FIG. 7B, the displacement amount due to the pulsation of the artery ART is Δd1 on the tube wall W1 and Δd2 on the tube wall W2, and the values of these displacement amounts Δd1 and Δd2 are It is calculated by the displacement amount calculation unit 17B. Then, the displacement amount correction unit 17C corrects the data from the displacement measurement unit 11 so that the positions of the tube walls W1 and W2 of the artery ART are restored based on the displacement amounts Δd1 and Δd2. Yes.

  FIG. 7B shows an ultrasonic tomographic image corresponding to the corrected data from the displacement measuring unit 11, and the position and width of the artery ART are substantially the same as those shown in FIG. 7A. ing. Further, the position of the tube wall w1 on the artery ART side in the vein VEN is almost the same as that shown in FIG. 7A, but the tube wall w2 on the body surface side is displaced by Δd toward the artery ART side. ing. The displacement due to Δd of the vein VEN is displayed as a displacement excluding the displacement due to the pulsation of the artery ART.

  Therefore, it is possible to recognize an accurate pulsation of the vein VEN and to accurately detect hardness information such as a thrombus in the blood.

  In the above-described embodiment, in order to specify the coordinates of the vessel walls W1 and W2 of the arterial ART, the pointer displayed on the screen of the image display 9 is set and operated by overlapping the position. It is. However, the coordinates of the blood vessel walls W1 and W2 of the artery ART may be automatically specified by detecting the boundary of the blood drawn in red, for example, by the so-called Doppler method.

  Each of the embodiments described above may be used alone or in combination. This is because the effects of the respective embodiments can be achieved independently or synergistically.

It is a block block diagram which shows one Example of the ultrasonic diagnosing device by this invention. FIG. 2 is a block configuration diagram illustrating an example of a main part of the configuration of FIG. 1 in more detail. It is explanatory drawing which showed notionally the operation | movement performed by the structure shown in FIG. It is a block block diagram which shows the other Example of the ultrasonic diagnosing device by this invention. FIG. 5 is a block configuration diagram showing an example of a main part of the configuration of FIG. 4 in more detail. It is explanatory drawing which showed notionally the operation | movement performed with the structure shown in FIG. It is explanatory drawing which showed notionally the operation | movement performed with the structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic probe, 2 ... Transmission circuit, 3 ... Reception circuit, 4 ... Ultrasonic transmission / reception control circuit, 5 ... Phased addition circuit, 6 ... Signal processing part, 7 ... Monochrome scanning Converter: 8 ... Switching adder, 9 ... Image display, 10 ... RF signal frame data selection unit, 11 ... Displacement measurement unit, 12 ... Strain amount and elastic modulus calculation circuit, 13 ... Color scan converter , 14... Velocity distribution detection circuit, 15... Console, 16... Control unit, 17 .. pulsation signal processing unit, VFD... Speed frame data, EFD ... elasticity frame data, VAFD. Data, EEFD: Elastic gradation frame data, vfm: Speed frame memory, efm: Elastic frame memory, vafm: Speed evaluation frame memory, eefm: Elastic gradation frame memory, ART ... artery, VEN ...... vein,

Claims (3)

An ultrasonic diagnostic apparatus comprising elastic image generation means for calculating a displacement of a measurement point on a tomographic image and generating an elastic image indicating the hardness or softness of a biological tissue based on the displacement, and specified by a Doppler method The velocity distribution detecting means for obtaining the speed information of the area and selecting the image area to be displayed based on the speed information, and the elastic image information for selecting the elastic image information corresponding to the image area selected by the speed distribution detecting means A selection means, and a pulsation signal processing unit that calculates a displacement amount of a pulsation location that is displaced by a pulsation, and performs correction to restore the position of the pulsation location,
The elasticity image generation means gives hue or luminance information to elasticity image information corresponding to the image area selected by the elasticity image information selection means, and based on the correction by the pulsation signal processing unit Generating an ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus according to claim 1, further comprising means for giving the velocity information to elastic image information corresponding to an image region not selected by the elastic image information selecting means.   The velocity distribution detection means compares the threshold information obtained in advance with the velocity information, and the elasticity image generation means does not display a region where the velocity information is larger than the threshold in the elasticity image. The ultrasonic diagnostic apparatus according to claim 1.

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