JP2013153831A - X-ray ct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus capable of easily obtaining the positional relationships between images that are referenced in diagnosis.SOLUTION: An X-ray CT apparatus in the embodiment includes a collection unit, an image forming unit, a generation unit, a display unit, and a control unit. The collection unit collects data by scanning a subject with X-rays. The image forming unit forms a first image and a second image by reconstructing the collected data under a first reconstruction conditions and a second reconstruction condition, respectively. The generation unit generates positional relationship information representing positional relationships between the first and second images based on the collected data. The control unit displays, on the display unit, display information based on the positional relationship information.

Description

  Embodiments described herein relate generally to an X-ray CT apparatus.

  An X-ray CT (Computed Tomography) device is a device that scans a subject with X-rays, collects data, and processes the collected data with a computer, thereby imaging the inside of the subject.

  Specifically, the X-ray CT apparatus emits X-rays to a subject a plurality of times from different directions, detects X-rays transmitted through the subject with an X-ray detector, and generates a plurality of detection data. collect. The collected detection data is A / D converted by the data collection unit and then transmitted to the data processing system. The data processing system forms projection data by pre-processing the detection data. Subsequently, the data processing system executes a reconstruction process based on the projection data to form tomographic image data. The data processing system forms volume data based on a plurality of tomographic image data as further reconstruction processing. The volume data is a data set representing a three-dimensional distribution of CT values corresponding to a three-dimensional region of the subject.

  The reconfiguration process is performed by applying an arbitrarily set reconfiguration condition. In addition, a plurality of volume data is formed from one projection data by applying various reconstruction conditions. The reconstruction conditions include FOV (field of view), reconstruction function, and the like.

  The X-ray CT apparatus can perform MPR (Multi Planar Reconstruction) display by rendering volume data in an arbitrary direction. The cross-sectional image (MPR image) displayed in MPR includes an orthogonal three-axis image and an oblique image. An orthogonal triaxial image is an axial image showing a cross section orthogonal to the body axis, a sagittal image showing a cross section of the subject along the body axis, and a coronal showing a cross section of the subject along the body axis. Show the image. The oblique image is an image showing a cross section other than the orthogonal three-axis image. Further, the X-ray CT apparatus renders volume data by setting an arbitrary line of sight, thereby forming a pseudo 3D image when the 3D region of the subject is viewed from this line of sight.

JP 2005-95328 A

  In image diagnosis, a large number of images (MPR images, pseudo three-dimensional images, etc.) obtained from volume data under various reconstruction conditions are referred to. These images differ in the size of the visual field, the position of the visual field, the cross-sectional position, and the like. Therefore, it is extremely difficult to make a diagnosis while grasping the positional relationship between these images. It is also difficult to grasp the reconstruction conditions for each image.

  The problem to be solved by the present invention is to provide an X-ray CT apparatus capable of easily grasping the positional relationship between images referred to in diagnosis.

  The X-ray CT apparatus according to the embodiment includes a collection unit, an image forming unit, a generation unit, a display unit, and a control unit. The collection unit scans the subject with X-rays and collects data. The image forming unit reconstructs the collected data under the first reconstruction condition and the second reconstruction condition, respectively, and forms a first image and a second image. The generation unit generates positional relationship information representing a positional relationship between the first image and the second image based on the collected data. The control unit causes the display unit to display display information based on the positional relationship information.

It is a block diagram showing the structure of the X-ray CT apparatus which concerns on embodiment. It is a flowchart showing the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is a flowchart showing the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is a flowchart showing the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment. It is a flowchart showing the operation example of the X-ray CT apparatus which concerns on embodiment. It is the schematic for demonstrating the operation example of the X-ray CT apparatus which concerns on embodiment.

  An X-ray CT apparatus according to an embodiment will be described with reference to the drawings.

[Constitution]
A configuration example of an X-ray CT apparatus 1 according to the embodiment will be described with reference to FIG. Since “image” and “image data” have a one-to-one correspondence, they may be regarded as the same.

  The X-ray CT apparatus 1 includes a gantry device 10, a bed device 30, and a console device 40.

(Mounting device)
The gantry device 10 is an apparatus that irradiates the subject E with X-rays and collects X-ray detection data transmitted through the subject E. The gantry device 10 includes an X-ray generator 11, an X-ray detector 12, a rotating body 13, a high voltage generator 14, a gantry driver 15, an X-ray diaphragm 16, a diaphragm driver 17, And a data collection unit 18.

  The X-ray generator 11 includes an X-ray tube that generates X-rays (for example, a vacuum tube that generates a cone-shaped or pyramid-shaped beam (not shown)). The generated X-rays are exposed to the subject E.

  The X-ray detection unit 12 includes a plurality of X-ray detection elements (not shown). The X-ray detection unit 12 detects X-ray intensity distribution data (hereinafter sometimes referred to as “detection data”) indicating the intensity distribution of X-rays transmitted through the subject E with an X-ray detection element, and the detection data is Output as a current signal.

  As the X-ray detector 12, for example, a two-dimensional X-ray detector (surface detector) in which a plurality of detection elements are arranged in two directions (slice direction and channel direction) orthogonal to each other is used. The plurality of X-ray detection elements are provided, for example, in 320 rows along the slice direction. By using a multi-row X-ray detector in this way, a three-dimensional region having a width in the slice direction can be imaged with one scan (volume scan). The slice direction corresponds to the body axis direction of the subject E, and the channel direction corresponds to the rotation direction of the X-ray generation unit 11.

  The rotating body 13 is a member that supports the X-ray generation unit 11 and the X-ray detection unit 12 at positions facing each other with the subject E interposed therebetween. The rotating body 13 has an opening that penetrates in the slice direction. A top plate on which the subject E is placed is inserted into the opening. The rotating body 13 is rotated along a circular orbit centered on the subject E by the gantry driving unit 15.

  The high voltage generator 14 applies a high voltage to the X-ray generator 11. The X-ray generator 11 generates X-rays based on this high voltage. The X-ray diaphragm unit 16 forms a slit (opening), and changes the size and shape of the slit so that the X-ray fan angle (divergence angle in the channel direction) output from the X-ray generation unit 11 and the X-rays are changed. Adjust the cone angle (spreading angle in the slice direction). The diaphragm drive unit 17 drives the X-ray diaphragm unit 16 to change the size and shape of the slit.

  A data collection unit 18 (DAS: Data Acquisition System) collects detection data from the X-ray detection unit 12 (each X-ray detection element). Further, the data collection unit 18 converts the collected detection data (current signal) into a voltage signal, periodically integrates and amplifies the voltage signal, and converts it into a digital signal. Then, the data collecting unit 18 transmits the detection data converted into the digital signal to the console device 40.

(Bed apparatus)
A subject E is placed on a top plate (not shown) of the bed apparatus 30. The couch device 30 moves the subject E placed on the top plate in the body axis direction. Moreover, the couch device 30 moves the top plate in the vertical direction.

(Console device)
The console device 40 is used for operation input to the X-ray CT apparatus 1. Further, the console device 40 reconstructs CT image data (tomographic image data and volume data) representing the internal form of the subject E from the detection data input from the gantry device 10. The console device 40 includes a control unit 41, a scan control unit 42, a processing unit 43, a storage unit 44, a display unit 45, and an operation unit 46.

  The control unit 41, the scan control unit 42, and the processing unit 43 include, for example, a processing device and a storage device. As the processing apparatus, for example, a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), or an ASIC (Application Specific Integrated Circuit) is used. The storage device is configured to include, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disc Drive). The storage device stores a computer program for executing the function of each unit of the X-ray CT apparatus 1. The processing device implements the above functions by executing these computer programs. The control unit 41 controls each unit of the apparatus.

  The scan control unit 42 integrally controls operations related to X-ray scanning. This integrated control includes control of the high voltage generation unit 14, control of the gantry driving unit 15, control of the aperture driving unit 17, and control of the bed apparatus 30. The control of the high voltage generator 14 is to control the high voltage generator 14 so that a predetermined high voltage is applied to the X-ray generator 11 at a predetermined timing. The control of the gantry driving unit 15 controls the gantry driving unit 15 so as to rotationally drive the rotating body 13 at a predetermined timing and a predetermined speed. The control of the diaphragm control unit 17 controls the diaphragm driving unit 17 so that the X-ray diaphragm unit 16 forms a slit having a predetermined size and shape. The control of the couch device 30 is to control the couch device 30 so that the top plate is moved to a predetermined position at a predetermined timing. In the volume scan, the scan is executed with the position of the top plate fixed. In the helical scan, the scan is executed while moving the top plate.

  The processing unit 43 performs various processes on the detection data transmitted from the gantry device 10 (data collection unit 18). The processing unit 42 includes a preprocessing unit 431, a reconstruction processing unit 432, a rendering processing unit 433, and a positional relationship information generation unit 434.

  The preprocessing unit 431 performs preprocessing including logarithmic conversion processing, offset correction, sensitivity correction, beam hardening correction, and the like on the detection data from the gantry device 10 to generate projection data.

  The reconstruction processing unit 432 generates CT image data (tomographic image data or volume data) based on the projection data generated by the preprocessing unit 431. As the reconstruction processing of the tomographic image data, for example, any method such as a two-dimensional Fourier transform method or a convolution / back projection method can be applied. The volume data is generated by interpolating a plurality of reconstructed tomographic image data. As volume data reconstruction processing, for example, an arbitrary method such as a cone beam reconstruction method, a multi-slice reconstruction method, an enlargement reconstruction method, or the like can be applied. In the volume scan using the multi-row X-ray detector described above, a wide range of volume data can be reconstructed.

  The reconstruction process is executed based on preset reconstruction conditions. The reconstruction condition includes various items (sometimes referred to as condition items). Examples of condition items include FOV (field of view) and reconstruction function. FOV is a condition item that defines the visual field size. The reconstruction function is a condition item that defines image quality characteristics such as image smoothing and sharpening. The reconstruction condition may be set automatically or manually. As an example of automatic setting, there is a method of selectively applying the contents set in advance for each imaging region corresponding to the designation of the imaging region. As an example of manual setting, there is a method of displaying a predetermined reconstruction condition setting screen on the display unit 45 and operating the reconstruction condition setting screen using the operation unit 46. The FOV is set by referring to an image or scanogram based on projection data. It is also possible to automatically set a predetermined FOV (for example, when setting the entire scan range as an FOV).

  The rendering processing unit 433 can execute, for example, MPR processing and volume rendering. The MPR process is an image process for generating MPR image data representing a section by setting an arbitrary section to the volume data generated by the reconstruction processing unit 42b and performing a rendering process. Volume rendering generates pseudo three-dimensional image data representing the three-dimensional region of the subject E by sampling volume data along an arbitrary line of sight (ray) and adding the values (CT values). Image processing.

  The positional relationship information generation unit 434 generates positional relationship information representing the positional relationship between images based on the detection data output from the data collection unit 18. The positional relationship information is generated when a plurality of images having different reconstruction conditions, particularly a plurality of images having different FOVs, are formed.

  When the reconstruction condition including the FOV is set, the reconstruction processing unit 432 identifies the data area of the projection data corresponding to the set FOV, and the reconstruction is performed based on the data area and other reconstruction conditions. Execute the process. Thereby, the volume data of the set FOV is generated. The positional relationship information generation unit 434 acquires positional information of this data area.

  When two or more volume data based on different reconstruction conditions are generated, position information about each volume data is obtained. These two or more pieces of position information can be associated with each other. As a specific example, coordinates based on a coordinate system defined in advance for the entire projection data are used as position information. Thereby, the position of two or more volume data can be expressed by the coordinates of the same coordinate system. These coordinates (combinations) serve as positional relationship information of these volume data, and further serve as positional relationship information of two or more images obtained by rendering these volume data.

  It is also possible to generate positional relationship information using a scanogram instead of projection data. Also in this case, as in the case of the projection data, the positional relationship information can be generated by expressing the FOV set by referring to the scanogram with the coordinates of the coordinate system defined in advance for the entire scanogram. This process is applicable not only in the case of volume scanning but also in the case of other scanning modes (helical scanning or the like).

(Storage unit, display unit, operation unit)
The storage unit 44 stores detection data, projection data, image data after reconstruction processing, and the like. The display unit 45 is configured by a display device such as an LCD (Liquid Crystal Display). The operation unit 46 is used for inputting various instructions and information to the X-ray CT apparatus 1. The operation unit 46 includes, for example, a keyboard, a mouse, a trackball, a joystick, and the like. The operation unit 46 may include a GUI (Graphical User Interface) displayed on the display unit 45.

[Operation]
The operation of the X-ray CT apparatus 1 according to this embodiment will be described. Hereinafter, first to fourth operation examples will be described. In the first operation example, a case where two or more images with overlapping FOVs are displayed will be described. In the second operation example, a case where an image having a maximum FOV (global image) is used as a map representing the distribution of FOV images (local images) included in the image will be described. In the third operation example, a case where a list of FOVs of two or more images is displayed will be described. In the fourth operation example, a case where the setting contents of the reconstruction condition are displayed will be described.

[First operation example]
In this operation example, two or more images with overlapping FOVs are displayed. Here, a case where two images having different FOVs are displayed will be described. Similar processing is executed when three or more images are displayed. The flow of this operation example is shown in FIG.

(S1: Collection of detection data)
First, the subject E is placed on the top plate of the bed apparatus 30 and inserted into the opening of the gantry apparatus 10. When a predetermined scan start operation is performed, the control unit 41 sends a control signal to the scan control unit 42. Upon receiving this control signal, the scan control unit 42 controls the high voltage generation unit 14, the gantry drive unit 15, and the aperture drive unit 17 to scan the subject E with X-rays. The X-ray detection unit 12 detects X-rays that have passed through the subject E. The data collection unit 18 collects detection data sequentially generated from the X-ray detector 12 along with the scan. The data collection unit 18 sends the collected detection data to the preprocessing unit 431.

(S2: Generation of projection data)
The preprocessing unit 431 performs the above-described preprocessing on the detection data from the data collection unit 18 to generate projection data.

(S3: First reconstruction condition setting)
A first reconstruction condition for reconstructing an image based on the projection data is set. This setting process includes FOV setting. The setting of the FOV is performed manually with reference to an image based on projection data, for example. When a scanogram is acquired separately, the FOV can be set with reference to this scanogram. Also, a predetermined FOV can be set automatically.

(S4: Generation of first volume data)
The reconstruction processing unit 432 generates first volume data by performing a reconstruction process based on the first reconstruction condition on the projection data.

(S5: Setting of second reconstruction condition)
Subsequently, the second reconstruction condition is set in the same manner as in step 3. This setting process also includes FOV settings.

(S6: Generation of second volume data)
The reconstruction processing unit 432 generates second volume data by performing a reconstruction process based on the second reconstruction condition on the projection data.

  FIG. 3 shows an outline of the processing of Step 3 to Step 6. Through the above process, the first volume data V1 generated by applying the reconstruction process based on the first reconstruction condition to the projection data P and the reconstruction process based on the second reconstruction condition are applied to the projection data P. The second volume data V2 generated by the application is obtained.

  The FOV of the first volume data V1 and the FOV of the second volume data V2 overlap. Here, it is assumed that the FOV of the first volume data V1 is included in the FOV of the second volume data V2. Such a setting is used, for example, when observing a wide area with an image based on the second volume data and observing a site of interest (an organ, a diseased part, etc.) with an image based on the first volume data.

(S7: Generation of positional relationship information)
The positional relationship information generation unit 434 acquires positional information about the set volume data of each FOV based on the projection data or scanogram, and generates positional relationship information by associating the two acquired positional information.

(S8: Generation of MPR image data)
The rendering processing unit 433 generates MPR image data (wide area MPR image data) based on the wide area volume data V2. The wide-area MPR image data may be any image data of orthogonal three-axis images, or may be image data of oblique images based on arbitrarily set cross sections.

  Also, the rendering processing unit 433 generates MPR image data (narrow band MPR image data) based on the narrow volume data V1 for the same cross section as the wide area MPR image data.

(S9: Display of wide area MPR image)
The control unit 41 causes the display unit 45 to display an image (wide area MPR image) based on the wide area MPR image data.

(S10: Display of FOV image)
Further, the control unit 41, based on the positional relationship information regarding the two volume data V1 and V2, outputs an FOV image representing the position of the image based on the narrow area MPR image data (the narrow area MPR image) in the wide area MPR image. Display over a wide area MPR image. Note that the FOV image may be displayed in response to the user performing a predetermined operation using the operation unit 46, or the FOV image may be always displayed while the wide area MPR image is displayed. .

  A display example of the FOV image is shown in FIG. In FIG. 4, the FOV image F1 representing the position of the narrow area MPR image in the wide area MPR image G2 is superimposed on the wide area MPR image G2.

(S11: Designation of FOV image)
The user designates the FOV image F1 using the operation unit 46 in order to display the narrow area MPR image. This designation operation is, for example, a click operation of the FOV image F1 with the mouse.

(S12: Display of narrow area MPR image)
When the FOV image F1 is designated, the control unit 41 causes the display unit 45 to display a narrow-area MPR image corresponding to the FOV image F1. The display mode at this time is, for example, one of the following: (1) Switching display from the wide MPR image G2 to the narrow MPR image G1 shown in FIG. 5A; (2) Wide MPR image G2 shown in FIG. And parallel display of the narrow area MPR image G1; (3) The superimposed display of the narrow area MPR image G1 on the wide area MPR image G2 shown in FIG. 5C. In the superimposed display, the narrow area image G1 is displayed at the position of the FOV image F1. The display mode to be executed may be set in advance, or may be selectable by the user. In the latter case, it is possible to switch the display mode according to the operation content by the operation unit 46. For example, in response to right-clicking on the FOV image F1, the control unit 41 displays a pull-down menu that presents the above three display modes. When the user clicks a desired display mode, the control unit 41 executes the selected display mode. This is the end of the description of the first operation example.

[Second operation example]
In this operation example, a global image is used as a map representing the distribution of local images. Here, the case where the distribution of two local images with different FOVs is presented will be described. The same process is executed when three or more local images are displayed. The flow of this operation example is shown in FIG.

(S21: Collection of detection data)
Similarly to the first operation example, the gantry device 10 collects detection data, and sends the collected detection data to the preprocessing unit 431.

(S22: Generation of projection data)
The preprocessing unit 431 performs the above-described preprocessing on the detection data from the gantry device 10 to generate projection data.

(S23: Generation of global volume data)
The reconstruction processing unit 432 generates volume data (global volume data) of the maximum FOV by reconstructing the projection data based on the reconstruction condition to which the maximum FOV is applied as the FOV condition item.

(S24: Setting of reconstruction condition for local image)
Similar to the first operation example, reconstruction conditions for each local image are set. The FOV in this reconstruction condition is included in the maximum FOV. Here, a reconstruction condition for the first local image and a reconstruction condition for the second local image are set.

(S25: Generation of local volume data)
The reconstruction processing unit 432 generates first local volume data by performing reconstruction processing based on the first local image reconstruction condition on the projection data. Further, the reconstruction processing unit 432 generates second local volume data by performing a reconstruction process based on the reconstruction condition for the second local image on the projection data.

  FIG. 7 shows an outline of the processing of Step 23 to Step 25. Through the above processing, the global volume data VG obtained by performing the reconstruction process on the projection data P based on the reconstruction condition (global reconstruction condition) of the maximum FOV and the reconstruction condition (local reconstruction) of the local FOV included in the maximum FOV. Local volume data VL1 and VL2 obtained by subjecting the projection data P to reconstruction processing based on (configuration conditions) are obtained.

(S26: Generation of positional relationship information)
The positional relationship information generation unit 434 acquires positional information on the set volume data VG, VL1, and VL2 of each FOV based on the projection data or scanogram, and associates the acquired three positional information with the positional relationship information. Is generated.

(S27: Generation of MPR image data)
The rendering processing unit 433 generates MPR image data (global MPR image data) based on the global volume data VG. This global MPR image data may be any image data of orthogonal three-axis images, or may be image data of oblique images based on arbitrarily set cross sections.

  In addition, the rendering processing unit 433, for the same cross section as the global MPR image data, MPR image data based on the local volume data VL1 (first local MPR image data) and MPR image data based on the local volume data VL2 (second Local MPR image data).

(S28: Display of FOV distribution map)
The control unit 41 displays a map (FOV distribution map) representing the local FOV distribution in the MPR image (global MPR image) based on the global MPR image data on the display unit 45 based on the positional relationship information generated in step 26. Let

  An example of the FOV distribution map is shown in FIG. The FOV distribution map includes a first FOV image (first local FOV image) FL1 that represents a range of first local MPR image data, and a second FOV image (a first FOV image that represents a range of second local MPR image data). The second local FOV image) FL2 is displayed superimposed on the global MPR image GG. Here, the local FOV images FL1 and FL2 may be displayed corresponding to the user performing a predetermined operation using the operation unit 46, or the local FOV is always displayed while the global MPR image GG is displayed. Images FL1 and FL2 may be displayed.

(S29: Designation of local FOV image)
The user designates a local FOV image corresponding to the local MPR image using the operation unit 46 in order to display a desired local MPR image. This designation operation is, for example, a click operation on a local FOV image with a mouse.

(S30: Display of local MPR image)
When the local FOV image is designated, the control unit 41 causes the display unit 45 to display a local MPR image corresponding to the designated local FOV image. The display mode at this time is, for example, switching display, parallel display, or superimposed display similar to the first operation example. This is the end of the description of the second operation example.

[Third operation example]
This operation example displays a list of FOVs of two or more images. Here, a case where a list of local FOVs is displayed within the maximum FOV will be described, but other list display modes may be applied. For example, it is possible to attach a name (part name, organ name, etc.) to each FOV and display a list of these names. The flow of this operation example is shown in FIG.

(S41: Collection of detection data)
Similarly to the first operation example, the gantry device 10 collects detection data, and sends the collected detection data to the preprocessing unit 431.

(S42: Generation of projection data)
The preprocessing unit 431 performs the above-described preprocessing on the detection data from the gantry device 10 to generate projection data.

(S43: Generation of global volume data)
Similar to the second operation example, the reconstruction processing unit 432 generates global volume data by reconstructing projection data based on a reconstruction condition to which the maximum FOV is applied.

(S44: Setting of reconstruction condition for local image)
Similar to the first operation example, reconstruction conditions for each local image are set. The FOV in this reconstruction condition is included in the maximum FOV. Here, two reconstruction conditions for the first and second local images are set, respectively.

(S45: Generation of local volume data)
In the same manner as in the second operation example, the reconstruction processing unit 432 performs the reconstruction processing based on the reconstruction conditions for the first and second local images on the projection data, respectively, thereby performing the first and second operations. Generate local volume data. By this processing, the global volume data VG and local volume data VL1 and VL2 shown in FIG. 7 are obtained.

(S46: Generation of positional relationship information)
The positional relationship information generation unit 434 acquires positional information on the set volume data VG, VL1, and VL2 of each FOV based on the projection data or scanogram, and associates the acquired three positional information with the positional relationship information. Is generated.

(S47: Generation of MPR image data)
Similar to the second operation example, the rendering processing unit 433 generates global MPR image data, first local MPR image data, and second local MPR image data based on the global volume data VG.

(S48: Display of FOV list information)
Based on the positional relationship information generated in step 46, the control unit 41 includes an FOV corresponding to the global MPR image data (global FOV), a first local FOV corresponding to the first local MPR image data, The second local FOV corresponding to the second local MPR image data is displayed on the display unit 45 as the list information (the FOV list information).

  A first example of the FOV list information is shown in FIG. In this FOV list information, the first local FOV image FL1 and the second local FOV image FL2 are presented in the global FOV image FG representing the range of the global FOV. A second example of the FOV list information is shown in FIG. The FOV list information includes a first local volume data image WL1 representing the range of the local volume data VL1, and a second local volume data image WL2 representing the range of the local volume data VL2, and the range of the global volume data VG. This is presented in the global volume data image WG.

(S49: FOV designation)
The user designates an FOV corresponding to the MPR image using the operation unit 46 in order to display a desired MPR image. This designation operation is, for example, a click operation of the name of the global FOV image, local FOV image, local volume data image, or FOV with the mouse.

(S50: MPR image display)
When the FOV is designated, the control unit 41 causes the display unit 45 to display an MPR image corresponding to the designated FOV. This is the end of the description of the third operation example.

[Fourth operation example]
In this operation example, the setting contents of the reconstruction condition are displayed. Here, a case will be described in which condition items having the same setting contents and condition items having different setting contents are displayed in different modes between two or more reconstruction conditions. This operation example can be added to any of the first to third operation examples. In addition, this operation example can be applied to any other operation. The flow of this operation example is shown in FIG. In this operation example, the case where two reconstruction conditions are set will be described, but the same processing can be performed when three or more reconstruction conditions are set. In the following description, the same steps as those in the first to third operation examples are included.

(S61: Reconfiguration condition setting)
A first reconstruction condition and a second reconstruction condition are set. It is assumed that the condition item of each reconstruction condition includes an FOV and a reconstruction function. As an example, in the first reconstruction condition, the FOV is the maximum FOV, the reconstruction function is a lung field function, and in the second reconstruction condition, the FOV is a local FOV, and the reconstruction function is the lung field. Suppose that it is a function.

(S62: Identification of condition items with different settings)
The control unit 41 specifies condition items having different setting contents between the first reconstruction condition and the second reconstruction function. In this operation example, since the FOV is different and the reconstruction function is the same, the FOV is specified as a condition item having different setting contents.

(S63: Display of reconstruction conditions)
The control unit 41 displays the condition item specified in step 62 and the other condition items in different modes. This display processing includes, for example, wide area MPR image and FOV image display processing in the first operation example, FOV distribution map display processing in the second operation example, or FOV list information display processing in the third operation example. It is executed at the same time.

  FIG. 13 shows a display example of reconstruction conditions when this operation example is applied to the first operation example. As shown in FIG. 4 of the first operation example, the wide area MPR image G2 and the FOV image F1 are displayed on the display unit 45.

  The display unit 45 includes a first condition display area C1 and a second condition display area C2. The control unit 41 displays the setting contents of the first reconstruction condition corresponding to the FOV image F1 (the narrow area MPR image G1) in the first condition display area C1, and the second corresponding to the wide area MPR image G2. The setting contents of the reconstruction condition are displayed in the second condition display area C2.

  In this operation example, the setting contents of the FOV are different and the setting contents of the reconstruction function are the same, so the setting contents of the FOV and the setting contents of the reconstruction function are presented in different modes. In FIG. 13, the setting contents of the FOV are presented in bold and underlined, and the setting contents of the reconstruction function are usually presented in bold letters and without underlining. Note that the display mode is not limited to this. For example, it is possible to apply an arbitrary display mode such as displaying differently set contents in a shaded manner or changing a display color.

[Action / Effect]
The operation and effect of the X-ray CT apparatus 1 according to this embodiment will be described.

  The X-ray CT apparatus 1 includes a collection unit (the gantry device 10), an image forming unit (a preprocessing unit 431, a reconstruction processing unit 432, and a rendering processing unit 433), a generation unit (a positional relationship information generation unit 434), A display unit 45 and a control unit 41 are provided. The collection unit scans the subject E with X-rays and collects data. The image forming unit reconstructs the collected data under a first reconstruction condition to form a first image, and reconstructs under the second reconstruction condition to form a second image. The generation unit generates positional relationship information representing a positional relationship between the first image and the second image based on the collected data. The control unit 41 causes the display unit 45 to display display information based on the positional relationship information. Examples of display information include FOV images, FOV distribution maps, and FOV list information. According to such an X-ray CT apparatus 1, it is possible to easily grasp the positional relationship between images reconstructed under different reconstruction conditions by referring to display information.

  The positional relationship information can be generated based on projection data or a scanogram. Any data can be used when performing a volume scan, and a scanogram can be used when performing a helical scan.

  When generating positional relationship information based on projection data, the following configuration can be applied. As described above, the image forming unit includes the preprocessing unit 431, the reconstruction processing unit 432, and the rendering processing unit 433. The preprocessing unit 431 performs preprocessing on the data collected by the gantry device 10 to generate projection data. The reconstruction processing unit 432 performs reconstruction processing on the projection data based on the first reconstruction condition to generate first volume data, and performs reconstruction processing on the projection data based on the second reconstruction condition. To generate second volume data. The rendering processing unit 433 performs rendering processing on the first volume data to form a first image, and performs rendering processing on the second volume data to form a second image. Then, the positional relationship information generation unit 434 generates positional relationship information based on the projection data.

  On the other hand, when the positional relationship information is generated based on the scanogram, the following configuration can be applied. The gantry device 10 acquires a scanogram by scanning the subject E with the X-ray irradiation direction fixed. The positional relationship information generation unit 434 generates positional relationship information based on the scanogram.

  When the FOV of the first image and the FOV of the second image overlap, information indicating the position of one image can be displayed on the other image. The following is an example of the configuration for that purpose. The first reconstruction condition and the second reconstruction condition include overlapping FOVs as condition items. The control unit 41 displays an FOV image (display information) representing the FOV of the first image so as to overlap the second image. Thereby, the position of the first image in the second image (that is, the positional relationship between the first image and the second image) can be easily grasped.

  When this configuration is applied, the first image can be displayed on the display unit 45 in response to the FOV image being specified using the operation unit 46. This display process is performed by the control unit 41. Thereby, the transition to the browsing of the first image can be performed smoothly. Examples of display control in this case include switching display from the second image to the first image, parallel display of the first image and the second image, and the first image and the second image. There is a superimposed display.

  Although the FOV image can be always displayed, the FOV image can be displayed in response to the user's request. In that case, the control unit 41 superimposes the FOV image on the second image in response to the operation unit 46 being operated (clicked or the like) while the second image is displayed on the display unit 45. Configured to display. Thereby, since it is possible to display the FOV image only when it is desired to confirm the position of the first image or when it is desired to view the first image, the FOV image does not interfere with the browsing of the second image.

  The image with the maximum FOV can be used as a map representing the distribution of local images. As an example of the configuration, the image forming unit forms a third image by performing reconstruction with the third reconstruction condition including the maximum FOV as the setting content of the FOV condition item. Then, the control unit 41 displays the FOV image of the first image and the FOV image of the second image so as to overlap the third image. This is an FOV distribution map as display information. By displaying such an FOV distribution map, it is possible to easily grasp how an image obtained under an arbitrary reconstruction condition is distributed within the maximum FOV. Even when this configuration is applied, it is possible to display the FOV image only when requested by the user. In addition, in response to any one of the FOV images displayed on the third image being designated by the user, a CT image corresponding to the FOV image can be displayed.

  It is possible to display a list of FOVs used in this diagnosis. This example does not display FOV images of other CT images on a certain CT image (third image) as described above, but displays a list of all or part of FOVs used in this diagnosis. Is. As a configuration example therefor, there is the following. Each of the first reconstruction condition and the second reconstruction condition includes FOV as a condition item. The control unit 41 causes the display unit 45 to display FOV information representing the FOV of the first image and FOV list information (display information) of the FOV information representing the FOV of the second image. Thereby, it is possible to easily grasp how the FOV used in this diagnosis is distributed. In this case, a (rough) position of each FOV may be recognized by displaying a simulated image (such as a contour image) of each organ together with the FOV image. When the user designates FOV information using the operation unit 46, the control unit 41 can be configured to display a CT image corresponding to the designated FOV on the display unit 45. Each FOV information is displayed in a display area having a size corresponding to the maximum FOV, for example.

  When displaying a list of some FOVs used in this diagnosis, for example, it is possible to classify the FOV for each organ and selectively display only the FOV relating to the designated organ. As a specific example, all FOVs applied in chest diagnosis are classified into a group of FOVs related to the lung and a group of FOVs related to the heart, and each group is selectively (exclusively) according to designation by the user or the like. It can be displayed. Further, it is possible to classify FOVs according to the setting contents of reconstruction conditions other than the FOV and selectively display only FOVs having the specified setting contents. As a specific example, in the condition item “reconstruction function”, all FOVs are classified into the FOV group of the setting content “lung field function” and the FOV group of “mediastinal function”, and according to the designation by the user or the like Each group can be selectively (exclusively) displayed.

  Not only the setting contents regarding the FOV but also arbitrary reconstruction conditions can be displayed. In that case, when there are condition items having different setting contents between different reconstruction conditions, the setting contents of the condition item can be displayed in a different manner from the setting contents of other condition items. Thereby, the user can easily recognize whether the setting contents are the same or different.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 X-ray CT apparatus 10 Base apparatus 11 X-ray generation part 12 X-ray detection part 13 Rotating body 14 High voltage generation part 15 Base drive part 16 X-ray aperture part 17 Aperture drive part 18 Data collection part 30 Bed apparatus 40 Console apparatus 41 Control unit 42 Scan control unit 43 Processing unit 431 Preprocessing unit 432 Reconstruction processing unit 433 Rendering processing unit 434 Position relation information generation unit 44 Storage unit 45 Display unit 46 Operation unit

Claims (12)

A collection unit that scans a subject with X-rays and collects data;
An image forming unit that reconstructs the collected data under a first reconstruction condition and a second reconstruction condition to form a first image and a second image;
Based on the collected data, a generating unit that generates positional relationship information representing a positional relationship between the first image and the second image;
A display unit;
An X-ray CT apparatus comprising: a control unit that causes the display unit to display display information based on the positional relationship information. The image forming unit includes:
A pre-processing unit that pre-processes data collected by the collecting unit to generate projection data;
A reconstruction processing unit that performs reconstruction processing on the projection data based on the first reconstruction condition and the second reconstruction condition to generate first volume data and second volume data, respectively;
A rendering processing unit that performs rendering processing on the first volume data and the second volume data to form the first image and the second image, respectively.
The X-ray CT apparatus according to claim 1, wherein the generation unit generates the positional relationship information based on the projection data. The acquisition unit acquires a scanogram by scanning the subject with a fixed X-ray irradiation direction,
The X-ray CT apparatus according to claim 1, wherein the generation unit generates the positional relationship information based on the scanogram. The first reconstruction condition and the second reconstruction condition include FOV (field of view) overlapping each other as a condition item,
The said control part displays the FOV image showing FOV of the said 1st image as the said display information so that it overlaps with the said 2nd image. The Claim 1 characterized by the above-mentioned. X-ray CT system. It further has an operation part,
The X-ray CT apparatus according to claim 4, wherein when the FOV image is designated using the operation unit, the control unit displays the first image on the display unit. When the FOV image is designated using the operation unit, the control unit switches the first display from the second image to the first image, the first display control, the first image, and the first image The second display control for displaying two images in parallel and the third display control for displaying the first image and the second image in a superimposed manner are executed. 5. The X-ray CT apparatus according to 5. It further has an operation part,
In response to the operation unit being operated when the second image is displayed on the display unit, the control unit displays the FOV image so as to overlap the second image. The X-ray CT apparatus according to claim 4. The image forming unit forms a third image by performing reconstruction with a third reconstruction condition including the maximum FOV as the setting content of the FOV condition item,
The said control part displays the FOV image of the said 1st image, and the FOV image of the said 2nd image as the said display information so that it may overlap and display on the said 3rd image. The X-ray CT apparatus as described in any one. It further has an operation part,
Each of the first reconstruction condition and the second reconstruction condition includes FOV as a condition item,
The control unit causes the display unit to display list information of FOV information representing the FOV of the first image and FOV information representing the FOV of the second image as the display information,
The control unit causes the display unit to display an image corresponding to the designated FOV when the FOV information is designated using the operation unit. An X-ray CT apparatus according to claim 1. The image forming unit forms a third image by performing reconstruction with a third reconstruction condition including the maximum FOV as the setting content of the FOV condition item,
The control unit causes the FOV information of the first image and the FOV information of the second image to be displayed as the list information so as to overlap the FOV information representing the maximum FOV. The X-ray CT apparatus described. The control unit causes the display unit to display setting contents of one or more condition items included in the first reconstruction condition and the second reconstruction condition. X-ray CT apparatus as described in any one of these. When there are condition items having different setting contents between the first reconstruction condition and the second reconstruction condition, the control unit sets the setting contents of the condition item as the setting contents of other condition items. The X-ray CT apparatus according to claim 11, wherein the display is performed in a different manner.

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