JP2005253572A - Image processor, x-ray diagnosis apparatus, medical image information system and calibration table attaching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor, an X-ray diagnosis apparatus, a medical image information system and a calibration table attaching method capable of simply creating and supplying precise image data at any time. <P>SOLUTION: This image processor is characterized in having an incidental data creation part 160 attaching a calibration table for correcting an imaging error of the X-ray diagnosis apparatus in the same imaging direction as image data obtained from X-ray imaging of a subject by the X-ray diagnosis apparatus, to the image data; and an image processing part 170 correcting the incidental image data of the calibration table formed by attaching the calibration table by the incidental data creation part 160 based on the calibration table attached to the incidental image data and creating correction image data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus that performs processing of image data obtained by X-ray imaging, an X-ray diagnostic apparatus, a medical image information system, and a calibration table supplementary method.

  Examination of the circulatory system using an X-ray diagnostic apparatus is performed by X-ray imaging of a blood vessel in which a contrast medium is injected into the blood vessel to enhance the contrast. In such a case, it is necessary to accurately grasp the three-dimensional structure of the blood vessel and the affected part.

  In order to meet such demands, an X-ray diagnostic apparatus for a circulatory system has an X-ray generator and an X-ray detector and a C arm that movably supports them. Thus, a three-dimensional blood vessel image can be reconstructed based on a plurality of image data obtained from multiple directions by moving the C-arm and X-ray imaging.

  However, since the C-arm of the X-ray diagnostic apparatus supports the heavy objects of the X-ray generator and the X-ray detector, rotation blur occurs due to the change over time due to the deflection of the C-arm, and the image data is reproduced. This causes problems of imaging errors that cannot be ignored, such as the occurrence of artifacts, and makes it difficult to accurately grasp the affected area of the subject.

  Further, the X-ray detector of the X-ray diagnostic apparatus includes the following problems. That is, in the case of an X-ray detector using an image intensifier, a problem of imaging error of X-ray projection data caused by distortion peculiar to the image intensifier is caused.

  In order to avoid the problem of imaging errors due to the above-described rotational shake of the C-arm, a rotational shake correction phantom is imaged in advance, a calibration table is created based on the image data obtained by imaging, and the subject There is disclosed a method of correcting image data obtained by photographing the image data using these calibration tables (see, for example, Patent Document 1).

  Further, in order to avoid the problem of distortion caused by the X-ray detector, a calibration for correcting based on the captured image data is performed in the same manner as in the case of the above-described rotational shake by capturing an image distortion correction phantom. An image table is created, and image data obtained by imaging the subject is corrected using these calibration tables.

  Such correction is performed by DA image (Digital Angiography) data obtained by imaging in a state in which a contrast medium is injected into the blood vessel, or mask image data and contrast medium obtained by imaging before injecting the contrast medium. It is often used when reconstructing DSA (Digital Subtraction Angiography) image data from which only blood vessel images are extracted by subtraction processing (subtraction processing) with contrast image data obtained by imaging after injection into 3D blood vessel images. The

By the way, various image data generated by the X-ray diagnostic apparatus is centrally managed in a hospital information system (HIS) or a radiation department information system (RIS) connected via a network. By reading out desired image data from the stored image data, for example, comparison of image data obtained by different image diagnostic apparatuses for the same patient (hereinafter referred to as a subject), or the same Comparison of past image data obtained by an image diagnostic apparatus with the latest image data is performed to improve diagnostic accuracy.
JP 2001-149363 A (page 4-6, FIG. 3)

  However, since the imaging error due to rotational fluctuation of the C-arm of the X-ray diagnostic apparatus and distortion of image data projected on the X-ray detector may change in the long term, the calibration table is updated in a predetermined period. There is a need to.

  Therefore, if it is necessary to correct the image data of the subject imaged before updating the calibration table after updating the calibration table, the calibration is performed by mixing the calibration table that has expired before the update and the calibration table after the update. In order to avoid misuse of the calibration table, it is necessary to store the calibration table before update in another location.

  The calibration table is unique to each X-ray diagnostic apparatus, and further, the field size (FOV) of the X-ray detector set in the X-ray diagnostic apparatus and the distance between the X-ray generator and the X-ray detector. For each shooting condition such as (SID), it is necessary to have a calibration table for correcting rotational blur and image data distortion.

  Therefore, in order to correct the image data of the subject and reconstruct it into an accurate three-dimensional image, it can be obtained from the same imaging direction and the same imaging conditions of the same X-ray diagnostic apparatus as the image data was captured. It is necessary to use a calibration table that is obtained from imaging within a predetermined period with respect to the imaging time of the image data.

  In addition, when supplying image data using a workstation, various image data and calibration tables having different imaging timings or imaging conditions are separately transmitted from the image processing apparatus, X-ray diagnostic apparatus, or data management system via a network. Therefore, the workstation side needs to select a calibration table for each image data, which complicates image processing.

  As described above, the calibration table is indispensable for obtaining an accurate image. However, if the calibration table is selected incorrectly, an accurate image cannot be obtained.

  The present invention has been made to solve the above problems, and is an image processing apparatus, an X-ray diagnostic apparatus, a medical image information system, and a calibration table capable of easily generating and supplying accurate image data at any time. The purpose is to provide incidental methods.

In order to achieve the above object, an image processing apparatus according to a first aspect of the present invention is provided with a calibration table that attaches a calibration table to image data obtained from X-ray imaging of a subject of an X-ray diagnostic apparatus. And image processing means for generating corrected image data by correcting the auxiliary image data with the calibration table attached thereto from the calibration table auxiliary means, and the calibration auxiliary means is in the same photographing direction as the image data. Attached with a calibration table for imaging error correction of the X-ray diagnostic apparatus,
The image processing means corrects the incidental image data based on a calibration table associated with the incidental image data.

  Next, the X-ray diagnostic apparatus of the present invention according to claim 2 is an X-ray generation unit that irradiates a subject with X-rays, and an X-ray that is irradiated with X-rays from the X-ray generation unit and transmitted through the subject. X-ray detection means for detecting a line, imaging direction setting means for setting an imaging direction of X-ray imaging by the X-ray generation means and the X-ray detection means, and the imaging direction with respect to the subject injected with a contrast agent An image data generation unit that generates image data based on X-ray projection data obtained in the imaging direction set by the setting unit, and a calibration table for correction of imaging errors in the imaging direction of the X-ray generation unit and the X-ray detection unit. Calibration table creation means to create, and a calibration table attached to the image data with a calibration table obtained from the same shooting direction as the image data Characterized by comprising a stage.

  According to a third aspect of the present invention, there is provided an X-ray diagnostic apparatus according to the present invention, wherein an X-ray generation unit irradiates a subject with X-rays, and X-rays irradiated with X-rays from the X-ray generation unit X-ray detection means for detecting the imaging, imaging direction setting means for setting the imaging direction of X-ray imaging by the X-ray generation means and the X-ray detection means, and the imaging direction setting for the subject injected with a contrast agent An image data generation means for generating image data based on X-ray projection data obtained in the imaging direction set by the means, and a calibration table for correction of imaging errors in the imaging direction of the X-ray generation means and the X-ray detection means A calibration table creating means for performing calibration, and a calibration table associated with a calibration table obtained from the same photographing direction as the image data. And a calibration table supplementary means comprising image processing means for correcting the supplementary image data supplemented with the calibration table and generating corrected image data, wherein the image processing means comprises calibration associated with the supplementary image data. The incidental image data is corrected based on a table.

  Furthermore, the medical image information system of the present invention according to claim 10 is obtained via an image database system for storing and supplying image data obtained from X-ray imaging of a subject by an X-ray diagnostic apparatus, and a network. A medical image information system including a workstation for generating the image data, wherein the image database system performs calibration for correction of imaging error of the X-ray diagnostic apparatus in the same imaging direction as the image data. Ancillary image data storage means of a calibration table for storing the ancillary image data of the calibration table, and image data transmission for transmitting the ancillary image data stored in the auxiliary image data storage means to the workstation via the network And the workstation has the network. Image processing for generating the corrected image data by correcting the incidental image data of the calibration table received from the image database system via the image based on the calibration table attached to the incidental image data It has the means.

  In the calibration table supplementary method of the present invention according to claim 11, an X-ray imaging direction by the X-ray generation unit and the X-ray detection unit is set by the imaging direction setting unit, and the X-ray generation unit and the X-ray are set. An X-ray obtained in the imaging direction set by the imaging direction setting unit with respect to the subject into which the contrast medium has been injected is created by a calibration table creating unit by means of a calibration table creation unit. Image data is generated by image data generation means based on projection data, and the calibration table obtained from the same photographing direction as the image data is attached to the image data by a calibration table auxiliary means. To do.

  According to the present invention, a calibration table suitable for image data can be easily used at any time by attaching a calibration table for correcting imaging errors by the X-ray diagnostic apparatus to image data obtained by X-ray imaging. Thus, the image data can be corrected to accurately reconstruct the image data.

  In addition, it is possible to provide image data that can be easily reconstructed accurately through a network.

  Embodiments of the present invention will be described below with reference to the drawings.

  The first embodiment of the X-ray diagnostic apparatus according to the present invention is characterized in that X-ray imaging is performed based on phantom image data obtained by imaging phantoms from a plurality of imaging directions in advance under predetermined imaging conditions. Create a calibration table for correcting shooting errors, and the created calibration table has a valid period for which a predetermined period is valid, and then within the valid period of the calibration table, the same shooting conditions and the same as the phantom In the case where the calibration table is attached to the image data of the subject obtained by photographing from the photographing direction, and then the image data of the subject attached with the calibration table is reconstructed into a three-dimensional image, The object is to correct the image data of the subject based on the attached calibration table.

  Embodiments of an X-ray diagnostic apparatus according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a diagram showing a configuration of an X-ray diagnostic apparatus according to the present invention. The X-ray diagnostic apparatus 100 two-dimensionally detects the X-ray generator 1 that irradiates the subject P with X-rays and the X-rays that have passed through the subject P, and based on the X-ray detection data, In the X-ray detection unit 2 that generates line image data, the X-ray generation unit 1 and the C-arm 5 that supports the X-ray detection unit 2, the top plate 17 on which the subject P is placed, and the X-ray generation unit 1 A high voltage generation unit 4 that generates a high voltage necessary for X-ray irradiation is provided.

  The X-ray diagnostic apparatus 100 creates and stores a calibration table based on the X-ray image data generated by the mechanism unit 3 that moves the C-arm 5 or the top plate 17 and the X-ray detection unit 2, Image data based on the incidental data generation unit 6 that attaches a calibration table to the X-ray image data and the incidental information of the image data (calibration incidental image data) generated by the accompanying data generation unit 6 And a display unit 8 for displaying desired corrected image data from the calibration-accompanying image data stored in the image processing unit 7.

  Furthermore, the X-ray diagnostic apparatus 100 supervises the operation unit 9 for selecting and inputting subject information, imaging conditions, and various display-related conditions, and inputting various commands, and the above units of the X-ray diagnostic apparatus 100. The system control part 10 to control is provided.

  The X-ray generator 1 includes an X-ray tube 15 that irradiates the subject P with X-rays, and an X-ray diaphragm that forms an X-ray weight (cone beam) with respect to the X-rays irradiated from the X-ray tube 15. 16 is provided.

  The X-ray detection unit 2 detects X-rays transmitted through the subject P by the image intensifier 21 and converts them into light, and the converted light forms image data that is an electrical signal by photographing with the television camera 22.

  The image intensifier 21 includes a moving mechanism that can move the position of the image intensifier 21 back and forth in the direction of the X-ray tube 15 (not shown), and the distance (SID) between the X-ray tube 15 and the image intensifier 21. Can be adjusted. The image intensifier 21 has an X-ray image receiving surface (not shown) on which X-rays transmitted through the subject P are incident. The image intensifier 21 controls the electrode voltage to input an X-ray input field size (FOV) on the X-ray image receiving surface. ) Can be adjusted.

  In addition, for an imaging error caused by a specific distortion known as a pincushion distortion or the like that the image intensifier 21 has in its structure, an image distortion correction calibration table obtained in advance based on an image distortion correction phantom is used. Thus, it is possible to correct the distortion of the image data obtained in the imaging of the subject P.

  The mechanism unit 3 includes a mechanism for moving the top plate 17 on which the subject P is placed in the longitudinal direction, moving in the width direction, moving up and down, and rotating to a predetermined angle. The top arm moving mechanism 32, the C arm rotating / moving mechanism 31 for rotating the C arm 5 supporting the X-ray generator 1 and the X-ray detector 2 around the subject P by a predetermined angle, and the C arm 5 A column turning / moving mechanism 34 for rotating and moving the supporting column 35, a column rotating / moving mechanism 34, a C arm rotating / moving mechanism 31, and a C arm / top plate mechanism 32 for controlling the table moving mechanism 32. A control unit 33 is provided.

  The C-arm / top plate mechanism control unit 33 then sets the optimum image magnification (that is, between the X-ray tube focus and the X-ray detector) for the diagnosis target region of the subject P according to the control signal from the system control unit 10. Distance) is set, and the C arm rotation / movement mechanism 31 is controlled to set the direction and size of the C arm 5 or the movement of the top plate 17, and the speed.

  Next, FIG. 2 is a diagram for explaining the moving directions of the X-ray generation unit 1 and the X-ray detection unit 2 driven by the C-arm rotation / movement mechanism 31 and the column rotation / movement mechanism 34.

  In FIG. 2, which shows a schematic configuration of the X-ray generation unit 1 and the X-ray detection unit 2, and the C arm 5, the C arm rotation / movement mechanism 31, and the column rotation / movement mechanism 34 for moving them, Alternatively, the C-arm rotation / movement mechanism 31 is supported on the column 35 installed on the ceiling so as to be rotatable in the R1 direction with the body axis direction of the subject P as the rotation axis.

  The C arm 5 is slidably attached to the C arm rotating / moving mechanism 31 in the R2 direction, and an X-ray generation unit 1 and an X-ray detection unit 2 are provided in the vicinity of both ends of the C arm 5. Is provided.

  Further, the column turning / moving mechanism 34 rotates in the R3 direction around the column 35 as a rotation axis, and horizontally moves in the L1 direction in the longitudinal direction of the top plate 17 at a rotation angle of the top plate 17 of 0 °. The horizontal movement of the top plate 17 in the L2 direction in the width direction is performed when the rotation angle of the top plate 17 is 0 °.

  Then, the X-ray generation unit 1 and the X-ray detection unit 2 slide in the R2 direction of the C arm 5, for example, in the head direction with the affected part (for example, heart) of the subject P as the rotation center (isocenter) C0 of the X-ray beam. Rotate in (CRA) and tail direction (CAU).

  Further, the X-ray generator 1 and the X-ray detector 2 rotate the C arm 5 in the R1 direction, for example, the first oblique direction (RAO) and the second oblique center around the isocenter of the subject P. It rotates with respect to the lateral direction (LAO).

  That is, the X-ray generator 1 and the X-ray detector 2 rotate in directions such as RAO, LAO, CRA, and CAU as the C-arm 5 rotates in the R1 and R2 directions. X-ray imaging from an arbitrary direction of the subject P is possible.

  Further, the imaging error due to the rotational shake of the C-arm 5 is obtained in the imaging of the subject P using the calibration table for rotational shake correction obtained in advance based on the imaging of the rotational shake correction phantom. It is possible to correct the rotational blur of the image data.

  Next, the high voltage generator 4 shown in FIG. 1 generates a high voltage applied between the anode and the cathode in order to accelerate the thermal electrons generated from the cathode of the X-ray tube 15. And an X-ray control unit 41 that controls X-ray irradiation conditions such as tube current, tube voltage, and irradiation time in the high voltage generator 42 in accordance with an instruction signal from the system control unit 10.

  The incidental data generation unit 6 generates a calibration table 61 for generating a calibration table, and generates image data of projection data of the subject P formed in the X-ray detection unit 2 as image data, and adds image data. A circuit 62 and an accompanying data generating circuit 65 for generating image data with calibration by attaching the calibration table generated by the calibration processing unit 61 to the image data generated by the image data generating circuit 62.

  Here, the calibration table creation circuit 63 of the calibration processing unit 61 uses the X-ray image projection data formed by the X-ray detection unit 2 by imaging of an imaging error correction phantom for image distortion correction and rotational distortion correction. A calibration table is created based on the above, and the created calibration table is stored in the calibration table storage circuit 64 with the shooting time of the shooting error correction phantom.

  Further, the incidental data generation circuit 65 selects the image data of the subject P from the calibration table stored in the calibration table storage circuit 64 for the image data of the subject P generated by the image data generation circuit 62. A calibration table selected within the predetermined period with respect to the time at which the image data was captured, and from the same imaging direction as the image data and from the same imaging conditions, and selected as the image data of the subject P Attached image data with a calibration table is generated.

  Next, the auxiliary data calculation circuit 71 of the image processing unit 7 uses the calibration table auxiliary image data generated by the auxiliary data generation unit 6 on the basis of the calibration table attached to the calibration auxiliary image data. It has a function of correcting image data.

  Further, the auxiliary data calculation circuit 71 is based on the calibration table that attaches the mask image data and the contrast image data with the calibration table obtained from the imaging in the same imaging direction and the same imaging conditions before and after the injection of the contrast medium. And a function of generating DSA image data by differential processing.

  Further, the incidental data calculation circuit 71 also has a function of reconstructing a three-dimensional image based on the calibration table incidental image data obtained from a plurality of imaging directions of the subject P.

  On the other hand, the supplementary data storage circuit 72 stores calibration supplementary image data such as DA image data and DSA image data supplemented with a calibration table. Various image data stored in the incidental data storage circuit 72 can be transmitted to the outside of the X-ray diagnostic apparatus 100 via the interface 90.

  The operation unit 9 is an interactive interface including an input device such as a keyboard, a trackball, a joystick, and a mouse, a display panel, and various switches, and is used to input subject information and a region to be imaged (target organ). Various imaging conditions such as X-ray irradiation conditions, image magnification, and the imaging direction by rotating the C-arm 5 are set, and various commands are input.

  The X-ray irradiation conditions include tube voltage applied to the X-ray tube 15, tube current, X-ray irradiation time, etc., and subject information includes age, sex, physique, examination site, examination method, and past diagnosis history and so on.

  The display unit 8 is for displaying two-dimensional image data such as DA image data, DSA image data, or three-dimensional image data with a calibration table stored in the auxiliary data storage circuit 72, A liquid crystal or CRT monitor is provided.

  The system control unit 10 includes a CPU and a storage circuit (not shown), and once stores information such as an operator command signal and imaging conditions supplied from the operation unit 9, X-ray image data based on these information is stored. The entire system is controlled such as generation, generation, reconstruction, and display of the above-described various image data, storage of control programs for various photographing operation processes, and control related to the moving mechanism.

  FIG. 3 is a diagram illustrating an image obtained by photographing the rotational shake correction phantom 110 and the rotational shake correction phantom 110. Here, the contents described in JP 2001-149363 A will be described as an example.

  The rotational blur correction phantom 110 shown in FIG. 3A is made of, for example, acrylic resin and is formed of two types of cylinders having a predetermined dimension and a hollow cross section having a different cross section diameter, and a cylinder 110a having a small cross section diameter, Cylinders 110b having a large cross-sectional diameter are arranged at both ends in the direction of the main axis 114 of the cylinder 110a having a small cross-sectional diameter so that the respective central axes coincide with each other.

  A plurality of metal balls 112 are spirally arranged with respect to the direction of the main axis 114 on the surface of the rotational shake correction phantom 110, and the metal of the cylinder 110b having a large distance between the metal balls 112 of the small cylinder 110a. They are arranged to be smaller than the distance between the spheres 112. Further, the plurality of metal balls 112 are arranged at intervals so as not to overlap on the X-ray projection image. Further, in the plurality of metal spheres 112, a metal sphere 112a serving as a central index larger than the other metal spheres 112 is arranged so that the metal spheres 112 can be distinguished from the other metal spheres 112 on the X-ray projection image.

  Next, the rotational shake correcting phantom 110 is used in accordance with the following usage. For example, when the image intensifier 21 of FIG. 2 having a size of 16 inches is used and image data is collected in the enlargement mode with the FOV set to 7 inches, the metal spheres 112 arranged on the entire small cylinder 110a are arranged. When a calibration table based on the image data is created and the FOV is set to 16 inches, a calibration table based on the image data of the metal ball 112 of the entire rotation blur correcting phantom 110 is created.

  Next, a procedure for creating a calibration table using the rotational shake correction phantom 110 will be described with reference to FIGS. 3B and 3C and FIGS.

  First, the rotational shake correcting phantom 110 is arranged so that its main shaft 114 is parallel to the plane of the image intensifier 21. For example, the rotational shake correction phantom 110 is placed on the top plate 17 of FIG. 2, and the focal point of the X-ray tube of the X-ray generator 1 supported by the C arm 5 of FIG. The line connecting the centers is arranged so as to be substantially perpendicular to the main axis 114. That is, the rotational shake correcting phantom 110 is arranged on the top plate 17 so that the longitudinal direction thereof is parallel to the top plate 17.

  Next, a shooting condition for shooting the rotation blur correcting phantom 110 is set. The FOV and SID described in FIG. 1 are set according to the size of the image intensifier 21 being used under a predetermined photographing condition, and C is set in the RAO and LAO directions shown in FIG. 2 for each FOV and SID condition. While the arm 5 is rotated, the rotation blur correcting phantom 110 is photographed at every predetermined angle.

  For example, when the size of the image intensifier 21 is 9 inches, the enlargement mode is set such that the SID and the FOV are 121 cm and 7 inches. Further, if the shooting range is set to 100 ° in the RAO and LAO directions, and the image data obtained from an arbitrary angle is set to one frame, the setting of one frame per 1 ° gives a total of 200 frames of image data. It will be.

  The image data obtained from the imaging of the rotational blur correction phantom 110 by X-ray irradiation of the X-ray tube 15 is temporarily stored in the calibration table storage circuit 64 of FIG.

  Next, the rotation blur correction phantom 110 is removed from the top plate 17 and image data without the rotation blur correction phantom 110 is collected under the same shooting conditions and procedure as when the rotation blur correction phantom 110 was photographed. I do. This operation may be performed before photographing the rotation blur correcting phantom 110.

  Then, for each frame, image data without the rotational shake correction phantom 110 and the rotational shake correction stored in the calibration table storage circuit 64 and photographed from the same angle as the image data without the rotational shake correction phantom 110 are taken. DSA image data from which only the metal sphere image is extracted from the image data of the phantom 110 for use by the subtraction processing of the calibration table creation circuit 63 in FIG. 1 is generated.

  3B and 3C, the DSA image 113 shown in FIG. 3B is an angle closest to the metal sphere 112a that serves as a center index of the rotation blur correcting phantom 110 when the C-arm 5 in FIG. 3 shows a part of the DSA image obtained by photographing at the position of the metal ball 112a, the projection point P0 of the metal sphere 112a image serving as the center index projected on the DSA image 113 of FIG. 3B, and the metal spheres 112b to 112f. The projected points P1 to P5 of the image are represented as projected points P0 to P5 arranged without overlapping each other in FIG.

  Next, the calibration table creation circuit 63 creates a rotation shake correction calibration table based on the generated DSA image 113, and the rotation shake correction phantom 110 is added to the created rotation shake correction calibration table. Is stored in the calibration table storage circuit 61.

  If a calibration table obtained from the same shooting direction and shooting conditions as the created calibration table is stored in the calibration table storage circuit 61, it is updated to the latest calibration table.

  By the way, the DSA image 113 obtained by photographing with the rotation blur correcting phantom 110 calculates the positions of all the metal spheres displayed in the image data on the basis of the largest metal sphere 112a from among the two-dimensional images. Expand to coordinates. Then, based on the two-dimensional image of the projection image of the three-dimensional coordinates of the metal sphere developed with reference to the largest metal sphere 112a of the rotational shake correction phantom 110, the DSA image 113 obtained by photographing the correction phantom 110. The projection error of the metal sphere 112 in the two-dimensional coordinates can be calculated. By selecting a parameter that minimizes the projection error for all the metal spheres projected by a predetermined parameter calculation algorithm, a correction coefficient associated with each rotation angle of the C arm 5 can be calculated.

  The above calculation is performed by the calibration table creation circuit 63, and the calculated correction coefficient is stored in the calibration table storage circuit 64 of FIG. 1 as a rotation shake correction calibration table.

  FIG. 4 is a diagram showing image data obtained by photographing the image distortion correction phantom 120 and the image distortion correction phantom 120. The image distortion correcting phantom 120 is a disk made of, for example, acrylic resin. In the disk, metal wires 122 are arranged in a lattice shape forming a substantially square shape at a predetermined interval.

  Next, a procedure for creating a calibration table using the image distortion correction phantom 120 will be described.

  First, the image distortion correcting phantom 120 is attached to the front surface of the image intensifier 21 of FIG. 2 so that the wire center 121 of the image distortion correcting phantom 120 is positioned at the center of the image intensifier 21.

  Next, shooting conditions for shooting the image distortion correction phantom 120 are set. The FOV and SID described in FIG. 1 are set according to the size of the image intensifier 21 used under a predetermined shooting condition, and the C-arm is set in the RAO and LAO directions shown in FIG. 2 for each FOV condition. While rotating, the image distortion correcting phantom 120 is photographed at every predetermined angle.

  For example, when the image intensifier 21 having a size of 9 inches is used, the SID and the FOV are set to 121 cm and 9 inches as in the case of shooting with the rotational blur correction phantom 110. Further, if the shooting range is set to 100 ° in the RAO and LAO directions, and the image data obtained from an arbitrary angle is set to one frame, the setting of one frame per 1 ° gives a total of 200 frames of image data. It will be.

  The image data obtained from the image distortion correction phantom 120 is temporarily stored in the calibration table storage circuit 64 of FIG.

  Next, the image distortion correction phantom 120 is removed from the image intensifier 21, and image data without the image distortion correction phantom 120 is collected under the same shooting conditions and procedure as those for the image distortion correction phantom 120. This operation may be performed before the image distortion correcting phantom 120 is photographed.

  Then, the image data obtained by photographing without the image distortion correction phantom 120 for each frame and the image data of the image distortion correction phantom 120 photographed from the same angle as this image data are used as the calibration table creation circuit 63 in FIG. The DSA image 123 from which only the wire 122 is extracted is generated by the subtraction process.

  Next, based on the generated DSA image 123, the calibration table creation circuit 63 creates an image distortion correction calibration table, and the created image distortion correction calibration table is captured by the image distortion correction phantom 120. The time is added and stored in the calibration table storage circuit 61.

  If a calibration table obtained from the same shooting direction and shooting conditions as the created image distortion correction calibration table is already stored in the calibration table storage circuit 61, the latest image distortion correction calibration table is stored. Updated to

  By the way, the DSA image 123 obtained by photographing with the image distortion correcting phantom 120 forms a substantially square lattice shape assumed when there is no distortion in the image data as it moves away from the center 121 of the wire. Compared with the ideal wire image 122b shown by (2), a distorted wire image 122a shown by a solid line is formed.

  Then, based on the two-dimensional image developed based on the ideal wire image 122b of the image distortion correction phantom 120, the distorted wire image in the two-dimensional coordinates of the DSA image 123 obtained by photographing the image distortion correction phantom 120. The distortion error of 122a can be calculated. A correction coefficient associated with each rotation angle of the C-arm 5 can be calculated by selecting parameters that minimize the projection error for all the gratings projected by a predetermined parameter calculation algorithm.

  The above-described calculation is performed by the calibration table creation circuit 63, and the calculated correction coefficient is stored in the calibration table storage circuit 64 of FIG. 1 as an image distortion correction calibration table.

  Next, a procedure from the creation of the calibration table described with reference to FIGS. 3 and 4 until the subject P is X-rayed and an image of the subject P is displayed on the display unit 8 will be described.

  First, various information such as the ID of the subject P, the imaging conditions, the imaging direction, the organ to be imaged, and the like are input by the operation of the operation unit 9, and the input imaging conditions and Projection data obtained by X-ray imaging of the subject P from the imaging direction is accompanied by information such as the imaging time, imaging conditions, and imaging direction of the subject P, and is once generated into DA image data by the image data generation circuit 62. Is done.

  Next, the incidental data generation circuit 65 is based on the incidental information of the DA image data of the subject P generated by the image data generation circuit 62, and from among the calibration tables stored in the calibration table storage circuit 61, A calibration table created based on the same imaging direction and the same imaging conditions as the X-ray imaging of the subject P is selected within a predetermined period with respect to the time when the subject P is imaged, and the selected calibration table is selected. Is generated with the calibration table attached to the DA image data of the subject, and then sent to the attached data storage circuit 72.

  The accompanying data storage circuit 72 stores the calibration accompanying image data of the subject P generated by the accompanying data generation circuit 65.

  Furthermore, by specifying the input information such as the three-dimensional image display of the subject P from the operation unit 9, that is, the target subject ID, the target organ, and the data acquisition date, the target calibration is performed based on the designation information. Table auxiliary image data is selected from the auxiliary data storage circuit 72, and the calibration auxiliary image data of the selected subject P is stored in the calibration table attached to the DA image data of the subject P by the auxiliary data calculation circuit 71. Based on this, the DA image data is corrected, a three-dimensional image is reconstructed, and the reconstructed three-dimensional image is displayed on the monitor of the display unit 8.

  In addition, before and after the injection of the contrast medium for the subject P, each of the accompanying image data of the calibration table obtained by performing the X-ray imaging in the same procedure as described above is generated by performing the difference processing in the accompanying data calculation circuit 71. The DSA image data to be corrected can be corrected based on the calibration table, reconstructed into a three-dimensional image, and displayed on the monitor of the display unit 8.

  According to the first embodiment of the present invention described above, the image data obtained from the X-ray imaging of the subject is within the effective period with respect to the time of the X-ray imaging of the subject and the X-ray of the subject. A calibration table for correcting a shooting error, which is created based on phantom shooting from the same shooting conditions and shooting direction as the shooting, is attached. This eliminates the need to select an appropriate calibration table for the image data of the subject, and easily corrects the image data using the calibration table attached to the image data of the subject at any time, thereby obtaining an accurate three-dimensional image. Can be reconfigured.

  Specifically, by supporting a heavy image intensifier, the deflection of the C-arm tends to increase over time, and the image intensifier supported by the C-arm changes slightly in its direction. This change in orientation is influenced by the geomagnetism, and for example, the image intensifier itself known as pincushion distortion causes structural changes in the structure and the C-arm rotation shake. For example, it is possible to provide a correctly corrected image using a calibration table in which the shooting time is taken into consideration for such distortion and rotational shake.

  A feature of the image processing apparatus according to the second embodiment of the present invention is that image data obtained from X-ray imaging of a subject by an X-ray diagnostic apparatus is within an effective period with respect to the X-ray imaging time of the image data. An imaging error correction calibration table created on the basis of the phantom imaging of the X-ray diagnostic apparatus in the same imaging conditions and in the same imaging direction as the image data is attached, and then the subject with the calibration table attached When the image data is reconstructed into a three-dimensional image, the subject image data is corrected based on the attached calibration table.

  Hereinafter, an embodiment of the image processing apparatus according to the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing the configuration of the image processing apparatus according to the present invention. The image processing apparatus 150 uses a calibration table obtained based on phantom imaging for correcting imaging errors in X-ray imaging, and image data obtained from X-ray imaging of a subject in the X-ray diagnostic apparatus 190. , An auxiliary data generation unit 160 for receiving a calibration table and adding the calibration table to the image data.

  Further, the image processing apparatus 150 includes an image processing unit 170 that corrects image data based on incidental information of image data (calibration table incidental image data) with the calibration table generated by the incidental data generation unit 160. The display unit 181 displays desired corrected image data from the calibration table-accompanying image data stored in the image processing unit 170.

  Further, the image processing apparatus 150 is a system that controls the above-mentioned units of the image processing apparatus 150 and the operation unit 182 that selects and inputs and inputs image processing conditions and various display-related conditions and inputs various commands. A control unit 180 is provided.

  The calibration table storage circuit 161 and the image data storage circuit 162 of the incidental data generation unit 160 correct an X-ray imaging error in the X-ray diagnostic apparatus 190 sent from the X-ray diagnostic apparatus 190 via the interface 183. The calibration table obtained from the phantom imaging and the image data obtained from the X-ray imaging of the subject are stored.

  Further, the incidental data generation circuit 163 of the incidental data generation unit 160 adds the image data stored in the image data storage circuit 162 to the image data within a predetermined period from the time when the image data was captured. A calibration table obtained from the same shooting direction and the same shooting conditions is attached to generate calibration-added image data.

  Next, the incidental data storage circuit 177 of the image processing unit 170 stores the calibration table incidental image data sent from the incidental data generation unit 160.

  The image calculation circuit 171 of the image processing unit 170 has a function of correcting the calibration-accompanying image data based on a calibration table accompanying the calibration-accompanying image data stored in the incidental data storage circuit 172. Yes.

  The image calculation circuit 171 also includes mask image data and contrast image data, which are obtained from X-ray imaging in the same imaging direction and under the same imaging conditions before and after the contrast agent injection by the X-ray diagnostic apparatus 190, and are accompanied by a calibration table. And a function of generating DSA image data by differential processing while correcting based on the calibration table.

  Furthermore, the image calculation circuit 171 also has a function of reconstructing three-dimensional image data based on calibration table-accompanying image data obtained from a plurality of imaging directions of the subject.

  On the other hand, the accompanying data storage circuit 172 also saves DA image data and DSA image data accompanied by a calibration table.

  Various image data stored in the auxiliary data storage circuit 172 can be transmitted to the outside of the image processing apparatus 150 via the interface 183.

  The operation unit 182 is an interactive interface including an input device such as a keyboard, a trackball, a joystick, and a mouse, a display panel, and various switches. The operation unit 182 sets various image processing conditions and inputs various commands.

  The display unit 181 includes image data after correction of image data such as DA image data and DSA image data with a calibration table stored in the auxiliary data storage circuit 172, and three-dimensional image data reconstructed in three dimensions. Etc., and a liquid crystal or CRT monitor is provided.

  The system control unit 180 includes a CPU and a storage circuit (not shown), and once stores information such as an operator command signal and image processing conditions supplied from the operation unit 182, the above-described various images based on the information. It controls the entire system such as data generation, reconstruction and display.

  According to the image processing apparatus 150 described above, input information of desired image data from the operation unit 182, that is, a target subject ID, a target organ, and a data acquisition date are specified, and the target is based on the specified information. The image data accompanied by the calibration table is selected from the accompanying data storage circuit 172, and the selected calibration-accompanying image data is displayed on the display unit 181.

  According to the second embodiment of the present invention described above, the image data obtained from the X-ray imaging of the subject can be easily attached at any time by attaching the calibration table for correcting the imaging error by the X-ray diagnostic apparatus. The image data of the subject can be corrected using a calibration table suitable for the image data of the subject.

  Further, not only the X-ray diagnostic apparatus 190 but also image data obtained from other X-ray diagnostic apparatuses such as the X-ray diagnostic apparatus 191 has a unique calibration table similar to the X-ray diagnostic apparatus 190 included in the image data. By storing the data together, it is possible to easily correct the image data using a calibration table suitable for the image data and display an accurate image.

  The third embodiment relating to the medical image information system of the present invention shown in FIG. 6 described below is characterized in that image data with a calibration table obtained from an X-ray diagnostic apparatus or image processing apparatus is obtained from a medical image database system. The image data sent to the workstation via the network, on the other hand, the image data with the calibration table transmitted from the medical image database system is generated based on the attached calibration table. It is in. Below, it demonstrates according to the image data which attached the calibration table transmitted from the X-ray diagnostic apparatus 100. FIG.

  The configuration of the medical image information system in the third embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing a configuration of the medical image information system. The medical image information system 200 includes a medical image database system 210 connected via a network 201 and a plurality of workstations 230-1 to 230-N. It has. The medical image database system 210 stores image data (hereinafter, referred to as first image data) attached with a calibration table obtained by the X-ray diagnostic apparatus 100, and also stores predetermined data via the network 201. Supply to a workstation (eg, workstation 230-1).

  On the other hand, the workstation 230-1 receives the first image data from the medical image database system 210, and corrects the first image data based on a calibration table attached to the first image data. The corrected image data is generated.

(Medical image database system)
Next, a medical image database system 210 in the medical information system 200 includes a data filing unit 211 that stores a plurality of first image data supplied from the separately installed X-ray diagnostic apparatus 100, and a data filing unit 211. A filing control unit 212 that controls storage of the first image data is provided.

  The medical image database system 210 also includes an interface 219 for transmitting / receiving first image data, control signals, and the like to / from the X-ray diagnostic apparatus 100, and a control signal and first image for the workstation 230-1. A network interface 220 for transmitting and receiving data and the like is provided.

  Then, the data filing unit 211 collects the two-dimensional or three-dimensional first image data of the subject collected using the X-ray diagnostic apparatus 100 and supplied via the interface 219, from the filing control unit 212. The data is stored in a predetermined storage area (not shown) according to the control signal.

  The filing control unit 212 controls the above units of the medical image database system 210 in an integrated manner.

  On the other hand, the workstation 230-1 includes an operation unit 231 that operates the workstation 230-1, a storage unit 232 that temporarily stores the first image data supplied from the medical image database system 210, and a first image. An auxiliary data calculation unit 233 for correcting the first image data based on a calibration table with data attached thereto, and a display unit 234 for displaying the second image data obtained by the correction, further comprising the above units. A control unit 235 for controlling and a network interface 236 for transmitting user information and receiving first image data to the medical image database system 210 are provided.

  The operation unit 231 of the workstation 230-1 includes an input device such as a keyboard, a trackball, and a mouse and a display panel on the operation panel. In the operation unit 231, the identification information of the medical image database system 210, Identification information (subject ID, data acquisition date, data ID, etc.) of the first image data stored in the data filing unit 11 of the medical image database system 210 is input by the user.

  Further, the storage unit 232 temporarily stores the identification information of the first image data input from the operation unit 231.

  Next, the display unit 234 includes a display image memory (not shown), a conversion circuit, and a monitor, and medical image data such as first image data obtained by the auxiliary data calculation unit 233 is temporarily stored in the storage unit 232. After that, the image data is synthesized in the display image memory of the display unit 234, and the conversion circuit of the display unit 234 converts the medical image data stored in the display image memory of the display unit 234 into D / A conversion and TV format conversion. The converted medical image data is displayed on the monitor of the display unit 234.

  Then, the control unit 235 controls the system control unit 218 of the medical image database system 210 through the above units of the workstation 230-1 and the network 201.

  The first image data generated by the image data generation and storage circuit 72 of the X-ray diagnostic apparatus 100 of FIG. 1 in this way is sent to the data filing unit 211 via the interface 90 of FIG. 1 and the interface 219 of the image database system 210. Supplied and stored.

  A medical image data generation procedure of this embodiment for generating medical image data using the first image data obtained by the X-ray diagnostic apparatus 100 will be described. In the following description, the first image data desired by the user of the workstation 230-1 is selected from the plurality of first image data stored in the medical image database system 210, and the selected first image data is selected. The procedure of the second image data obtained by correcting the image data will be described.

  The user uses the input device and the display panel provided in the input unit 31 of the workstation 230-1 to store the medical subject ID, the target organ name, and the first image data of the subject. The identification information of the image database system 210 and the date of acquisition of the data are input (step S1 in FIG. 3). The control unit 235 of the workstation 230-1 temporarily stores the input information in a storage circuit (not shown) of the control unit 235 and performs filing via the network interface 36, the network 5, and the network interface 220 of the medical image database system 210. It supplies to the control part 212. In the following description, when various data is transmitted / received via the network 201, the description of the network interface 236 and the network interface 220 is omitted.

  The filing control unit 212 of the medical image database system 210 that has received the input information via the network 201 sets the target information based on the input information, that is, the target subject ID, the target organ, and the data acquisition date. 1 image data is selected from the data filing unit 211, and the selected first image data is temporarily stored in a buffer memory (not shown) and then stored in the storage unit 232 of the workstation 230-1 via the network 201. To do. Next, the control unit 235 of the workstation 230-1 reads the first image data stored in the storage unit 232, and first uses the calibration table attached to the first image data by the auxiliary data calculation unit 233. After the image data is corrected, the three-dimensionally reconstructed image data and the two-dimensional image data are displayed on a monitor (not shown) of the display unit 234.

  According to the present invention described above, by supplying the image data with the calibration table stored in the medical image database system 210 to the workstation 230-1 via the network 5, the workstation 230-1 Since the user can correct the image data without error, it is possible to easily obtain correct image data anytime and anywhere.

The figure which shows the structure of the X-ray diagnostic apparatus which concerns on Example 1 of this invention. The figure which shows operation | movement of the arm which concerns on Example 1 of this invention. FIG. 5 is a diagram illustrating creation of a rotation shake correction calibration table according to the first embodiment of the invention. FIG. 6 is a diagram illustrating creation of an image distortion correction calibration table according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating a configuration of an image processing apparatus according to a second embodiment of the invention. The figure which shows the medical image information system which concerns on Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 X-ray diagnostic apparatus 150 Image processing apparatus 160 Attached data generation part 161 Calibration table storage circuit 162 Image data storage circuit 163 Attached data generation circuit 170 Image processing part 171 Image arithmetic circuit 172 Attached data storage circuit 180 System control part 181 Display part 182 Operation unit 183 Interface 190 X-ray diagnostic apparatus 191 X-ray diagnostic apparatus

Claims (11)

A calibration table auxiliary means for attaching a calibration table to the image data obtained from the X-ray imaging of the subject of the X-ray diagnostic apparatus;
The calibration table supplementary means comprises image processing means for correcting the supplementary image data with the calibration table and generating corrected image data,
The calibration accessory means attaches a calibration table for correction of imaging errors of the X-ray diagnostic apparatus in the same imaging direction as the image data,
The image processing apparatus, wherein the image processing unit corrects the incidental image data based on a calibration table associated with the incidental image data. X-ray generation means for irradiating the subject with X-rays;
X-ray detection means for irradiating X-rays from the X-ray generation means and detecting X-rays transmitted through the subject;
An imaging direction setting means for setting an imaging direction of X-ray imaging by the X-ray generation means and the X-ray detection means;
Image data generating means for generating image data based on X-ray projection data obtained in the imaging direction set by the imaging direction setting means for the subject injected with a contrast agent;
Calibration table creation means for creating a calibration table for imaging error correction in the imaging direction of the X-ray generation means and the X-ray detection means;
An X-ray diagnostic apparatus comprising: a calibration table auxiliary means for attaching a calibration table obtained from the same imaging direction as the image data to the image data. X-ray generation means for irradiating the subject with X-rays;
X-ray detection means for irradiating X-rays from the X-ray generation means and detecting X-rays transmitted through the subject;
An imaging direction setting means for setting an imaging direction of X-ray imaging by the X-ray generation means and the X-ray detection means;
Image data generating means for generating image data based on X-ray projection data obtained in the imaging direction set by the imaging direction setting means for the subject injected with a contrast agent;
Calibration table creation means for creating a calibration table for imaging error correction in the imaging direction of the X-ray generation means and the X-ray detection means;
A calibration table auxiliary means for attaching a calibration table obtained from the same photographing direction as the image data to the image data;
The calibration table auxiliary means comprises image processing means for correcting the auxiliary image data attached with the calibration table and generating corrected image data,
The image processing apparatus, wherein the image processing unit corrects the incidental image data based on a calibration table associated with the incidental image data.   4. The imaging direction setting means sets the FOV and SID of X-ray imaging by the X-ray generation means and X-ray detection means together with the imaging direction. An X-ray diagnostic apparatus according to any one of the above.   The calibration table auxiliary means includes a calibration table obtained by imaging a phantom that corrects imaging errors due to distortion of X-ray projection data to the X-ray detection means in the same imaging direction as the image data. 4. The X-ray diagnostic apparatus according to claim 2, wherein the X-ray diagnostic apparatus is attached.   The calibration table auxiliary means is a calibration obtained by photographing a phantom that corrects photographing errors caused by rotational shaking in the photographing direction of the X-ray generating means and X-ray detecting means in the photographing direction of the image data. The X-ray diagnostic apparatus according to claim 2 or 3, wherein an X-ray diagnostic table is attached.   The calibration table supplement means is configured to attach a calibration table obtained from the same photographing direction as the image data within a predetermined period with respect to the time when the image data was photographed to the image data. The X-ray diagnostic imaging apparatus according to claim 2, wherein the X-ray diagnostic imaging apparatus is provided.   The image processing means is obtained by X-ray imaging of the subject under the same imaging conditions as the mask image data obtained by X-ray imaging before contrast medium injection and the mask image data after contrast medium injection. The X-ray image diagnostic apparatus according to claim 3, wherein the apparatus generates DSA (Digital Subtraction Angiography) image data based on the contrast image data obtained.   8. The three-dimensional image according to claim 3, wherein the image processing means generates a three-dimensional image based on auxiliary image data of a calibration table obtained by X-ray imaging from a plurality of imaging directions. The X-ray diagnostic imaging apparatus according to any one of the above. Medical image information including an image database system that stores and supplies image data obtained from X-ray imaging of a subject by an X-ray diagnostic apparatus, and a workstation that generates the image data obtained via a network A system,
The image database system includes:
Ancillary image data storage means of a calibration table for storing ancillary image data of an imaging error correction calibration table of the X-ray diagnostic apparatus in the same imaging direction as the image data;
Image data transmission means for transmitting the auxiliary image data stored in the auxiliary image data storage means to the workstation via the network;
The workstation is
Image processing for generating corrected image data by correcting the incidental image data of the calibration table received from the image database system via the network based on the calibration table attached to the incidental image data A medical image information system comprising means. The radiographing direction setting unit sets the radiographing direction of the X-ray radiographing by the X-ray generation unit and the X-ray detection unit
A calibration table creation unit creates a calibration table for correction of imaging errors in the imaging direction of the X-ray generation unit and the X-ray detection unit,
Generating image data by the image data generating means based on the X-ray projection data obtained in the imaging direction set by the imaging direction setting means for the subject injected with the contrast agent;
A calibration table attachment method characterized in that the calibration table obtained from the same photographing direction as the image data is attached to the image data by a calibration table attachment means.

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