JP2019146789A - Magnetic resonance imaging apparatus - Google Patents

Abstract

To provide a magnetic resonance imaging apparatus which more appropriately displays a reference image viewed to confirm positioning of a region of interest.SOLUTION: A magnetic resonance imaging apparatus comprises a positioning unit, a display control unit, and an imaging control unit. The positioning unit positions the region of interest on a positioning image of a subject displayed on a display unit. The display control unit generates a reference image corresponding to the position of the region of interest on the basis of an input image related to the subject, and displays the reference image on the display unit. After completion of positioning of the region of interest, the imaging control unit captures an image corresponding to the position of the region of interest in the subject. In response to the purpose of imaging to be performed after the completion of the positioning of the region of interest, the display control unit selects the input image out of at least one image related to the subject.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a magnetic resonance imaging apparatus.

  2. Description of the Related Art Conventionally, in a magnetic resonance imaging (MRI) apparatus, when a subject is imaged, a technique for positioning a region of interest to be imaged using a previously imaged image of the same subject as a positioning image. It has been known.

JP 2009-207777 A JP 2007-000629 A

  The problem to be solved by the present invention is to display a reference image referred to in order to confirm the positioning of the region of interest more appropriately.

  The magnetic resonance imaging apparatus according to the embodiment includes a positioning unit, a display control unit, and an imaging control unit. The positioning unit positions a region of interest on the positioning image of the subject displayed on the display unit. The display control unit generates a reference image corresponding to the position of the region of interest based on an input image related to the subject and displays the reference image on the display unit. The imaging control unit captures an image corresponding to the position of the region of interest in the subject after the positioning of the region of interest is completed. The display control unit selects the input image from at least one image related to the subject according to the purpose of imaging performed after the positioning of the region of interest is completed.

FIG. 1 is a diagram illustrating a configuration example of an MRI apparatus according to the first embodiment. FIG. 2 is a flowchart illustrating a processing procedure of processing performed by the MRI apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a display example of various images displayed by the MRI apparatus according to the first embodiment. FIG. 4 is a diagram illustrating an example of image alignment performed by the MRI apparatus according to the second embodiment.

  Hereinafter, embodiments of an MRI apparatus will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of an MRI apparatus according to the first embodiment.

  For example, as shown in FIG. 1, the MRI apparatus 100 according to the present embodiment includes a static magnetic field magnet 1, a gradient magnetic field coil 2, a gradient magnetic field power source 3, a whole body (WB) coil 4, a transmission circuit 5, and a local coil. 6, receiving circuit 7, RF shield 8, gantry 9, bed 10, interface 11, display 12, storage circuit 13, and processing circuits 14-17.

  The static magnetic field magnet 1 generates a static magnetic field in an imaging space for imaging the subject S. Specifically, the static magnetic field magnet 1 is formed in a hollow, substantially cylindrical shape (including a shape in which a cross-sectional shape orthogonal to the central axis of the cylinder is elliptical), and is an imaging space disposed in the cylinder. A static magnetic field is generated. For example, the static magnetic field magnet 1 includes a cooling container formed in a substantially cylindrical shape, and a magnet such as a superconducting magnet immersed in a coolant (for example, liquid helium) filled in the cooling container. Here, for example, the static magnetic field magnet 1 may generate a static magnetic field using a permanent magnet.

  The gradient magnetic field coil 2 is arranged inside the static magnetic field magnet 1 and generates a gradient magnetic field along a plurality of axial directions in an imaging space for imaging the subject S. Specifically, the gradient magnetic field coil 2 is formed in a hollow substantially cylindrical shape (including a shape in which a cross-sectional shape perpendicular to the central axis of the cylinder is elliptical), and is an imaging space disposed in the cylinder. In addition, gradient magnetic fields are generated along the X-axis, Y-axis, and Z-axis directions orthogonal to each other. Here, the X axis, the Y axis, and the Z axis constitute an apparatus coordinate system unique to the MRI apparatus 100. For example, the Z axis coincides with the cylinder axis of the gradient magnetic field coil 2 and is set along the magnetic flux of the static magnetic field generated by the static magnetic field magnet 1. The X axis is set along a horizontal direction orthogonal to the Z axis, and the Y axis is set along a vertical direction orthogonal to the Z axis. The configuration of the gradient coil 2 will be described later in detail.

  The gradient magnetic field power source 3 supplies a current to the gradient magnetic field coil 2 to generate a gradient magnetic field along the X-axis, Y-axis, and Z-axis directions in the space inside the gradient magnetic field coil 2. A current path for generating a gradient magnetic field along the X-axis direction is also referred to as an X channel, and a current path for generating a gradient magnetic field along the Y-axis direction is also referred to as a Y channel. The current path for generating a gradient magnetic field along the direction is also called a Z channel.

  In this way, the gradient magnetic field power supply 3 generates gradient magnetic fields along the X-axis, Y-axis, and Z-axis directions, so that the gradient magnetic fields along the readout direction, the phase encoding direction, and the slice direction, respectively. Can be generated. The axes along the readout direction, the phase encoding direction, and the slice direction constitute a logical coordinate system for defining a slice area or volume area to be imaged. Hereinafter, the gradient magnetic field along the readout direction is referred to as a readout gradient magnetic field, the gradient magnetic field along the phase encoding direction is referred to as a phase encoding gradient magnetic field, and the gradient magnetic field along the slice direction is referred to as a slice gradient magnetic field. .

  Each gradient magnetic field is superimposed on a static magnetic field generated by the static magnetic field magnet 1 and gives spatial position information to a magnetic resonance (MR) signal generated from the subject S. Specifically, the readout gradient magnetic field gives the MR signal position information along the readout direction by changing the frequency of the MR signal in accordance with the position in the readout direction. Further, the phase encoding gradient magnetic field changes the phase of the MR signal along the phase encoding direction, thereby giving position information in the phase encoding direction to the MR signal. Further, the slice gradient magnetic field gives positional information along the slice direction to the MR signal. For example, the slice gradient magnetic field is used to determine the direction, thickness, and number of slice areas when the imaging area is a slice area, and according to the position in the slice direction when the imaging area is a volume area. And used to change the phase of the MR signal.

  The WB coil 4 is disposed inside the gradient magnetic field coil 2 and functions as a transmission coil for applying an RF magnetic field to an imaging space for imaging the subject S and an MR generated from the subject S due to the influence of the RF magnetic field. An RF coil having a function of a receiving coil for receiving a signal. Specifically, the WB coil 4 is formed in a hollow, substantially cylindrical shape (including one that has an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and is supplied with an RF pulse supplied from the transmission circuit 5. Based on the signal, an RF magnetic field is applied to the imaging space arranged in the cylinder. The WB coil 4 receives an MR signal generated from the subject S due to the influence of the RF magnetic field, and outputs the received MR signal to the receiving circuit 7.

  The transmission circuit 5 outputs an RF wave signal corresponding to the Larmor frequency to the WB coil 4. Specifically, the transmission circuit 5 includes an oscillator, a phase selector, a frequency converter, an amplitude modulator, and an RF amplifier. The oscillator generates an RF wave (high frequency) signal having a resonance frequency (Larmor frequency) specific to a target nucleus placed in a static magnetic field. The phase selector selects the phase of the RF wave signal. The frequency converter converts the frequency of the RF wave signal output from the phase selector. The amplitude modulator generates an RF pulse signal by modulating the amplitude of the RF wave signal output from the frequency converter with, for example, a waveform of a sinc function. The RF amplifier amplifies the power of the RF pulse signal output from the amplitude modulator and outputs the amplified signal to the WB coil 4.

  The local coil 6 is an RF coil having a function of a receiving coil that receives MR signals generated from the subject S. Specifically, the local coil 6 is mounted on the subject S arranged inside the WB coil 4 and receives MR signals generated from the subject S due to the influence of the RF magnetic field applied by the WB coil 4. The received MR signal is output to the receiving circuit 7. For example, the local coil 6 is a receiving coil prepared for each part to be imaged, and includes a receiving coil for the head, a receiving coil for the neck, a receiving coil for the shoulder, a receiving coil for the chest, and a receiving coil for the abdomen. A receiving coil, a receiving coil for the lower limb, a receiving coil for the spine, and the like. The local coil 6 may further have a function of a transmission coil that applies an RF magnetic field to the subject S. In this case, the local coil 6 is connected to the transmission circuit 5 and applies an RF magnetic field to the subject S based on the RF pulse signal supplied from the transmission circuit 5.

  The receiving circuit 7 generates MR signal data based on the MR signal output from the WB coil 4 or the local coil 6, and outputs the generated MR signal data to the processing circuit 15. For example, the receiving circuit 7 includes a selector, a pre-stage amplifier, a phase detector, and an A / D (Analog / Digital) converter. The selector selectively inputs the MR signal output from the WB coil 4 or the local coil 6. The pre-stage amplifier power-amplifies the MR signal output from the selector. The phase detector detects the phase of the MR signal output from the pre-stage amplifier. The A / D converter generates MR signal data by converting the analog signal output from the phase detector into a digital signal, and outputs the generated MR signal data to the processing circuit 15.

  The RF shield 8 is disposed between the gradient magnetic field coil 2 and the WB coil 4 and shields the gradient magnetic field coil 2 from the RF magnetic field generated by the WB coil 4. Specifically, the RF shield 8 is formed in a hollow substantially cylindrical shape (including a shape in which a cross-sectional shape orthogonal to the central axis of the cylinder is elliptical), and on the inner peripheral side of the gradient coil 2. It arrange | positions so that the outer peripheral surface of WB coil 4 may be covered in space.

  The gantry 9 accommodates the static magnetic field magnet 1, the gradient magnetic field coil 2, the WB coil 4, and the RF shield 8. Specifically, the gantry 9 has a hollow bore B formed in a substantially cylindrical shape, and includes a static magnetic field magnet 1, a gradient magnetic field coil 2, a WB coil 4, and an RF shield 8 so as to surround the bore B. Each is accommodated in the state of arrangement. Here, the space inside the bore B of the gantry 9 is an imaging space in which the subject S is arranged when the subject S is imaged.

  Here, an example in which the MRI apparatus 100 has a so-called tunnel type configuration in which the static magnetic field magnet 1, the gradient magnetic field coil 2, and the WB coil 4 are each formed in a substantially cylindrical shape will be described. Is not limited to this. For example, the MRI apparatus 100 has a so-called open type configuration in which a pair of static magnetic field magnets, a pair of gradient magnetic field coils, and a pair of RF coils are disposed so as to face each other with an imaging space in which the subject S is disposed. You may do it.

  The bed 10 includes a top plate 10a on which the subject S is placed. When the subject S is imaged, the top plate 10a is inserted inside the bore B of the gantry 9. For example, the bed 10 is installed such that the longitudinal direction is parallel to the central axis of the static magnetic field magnet 1.

  The interface 11 receives various instructions and various information input operations from the operator. Specifically, the interface 11 is connected to the processing circuit 17, converts an input operation received from the operator into an electrical signal, and outputs the electrical signal to the processing circuit 17. For example, the interface 11 includes a touch pad for performing an input operation by touching a trackball, a switch button, a mouse, a keyboard, and an operation surface for setting an imaging condition, a region of interest (ROI), and the like, a display screen And a touch pad integrated with each other, a non-contact input circuit using an optical sensor, a voice input circuit, and the like. In the present specification, the interface 11 is not limited to the one having physical operation parts such as a mouse and a keyboard. For example, an example of the interface 11 includes an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the apparatus and outputs the electric signal to the control circuit. The interface 11 is an example of a means for realizing the input unit.

  The display 12 displays various information and various images. Specifically, the display 12 is connected to the processing circuit 17, converts various information and various image data sent from the processing circuit 17 into electrical signals for display and outputs them. For example, the display 12 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, or the like. The display 12 is an example of a means for realizing a display unit.

  The storage circuit 13 stores various data. Specifically, the storage circuit 13 stores MR signal data and image data. For example, the storage circuit 13 is realized by a semiconductor memory device such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like. The storage circuit 13 is an example of a storage unit realizing unit.

  The processing circuit 14 has a bed control function 14a. The couch control function 14 a is connected to the couch 10 and outputs an electric signal for control to the couch 10 to control the operation of the couch 10. For example, the couch control function 14a receives an instruction from the operator to move the couchtop 10a in the longitudinal direction, the up-down direction, or the left-right direction via the interface 11, and moves the couchtop 10a according to the received instruction. The drive mechanism of the top plate 10a which 10 has is operated.

  The processing circuit 15 has a data collection function 15a. The data collection function 15a collects MR signal data of the subject S by driving the gradient magnetic field power source 3, the transmission circuit 5, and the reception circuit 7.

  Specifically, the data collection function 15a collects MR signal data by executing various pulse sequences based on the sequence execution data output from the processing circuit 17. Here, the sequence execution data is information defining a pulse sequence indicating a procedure for collecting MR signal data. Specifically, the sequence execution data includes the timing at which the gradient magnetic field power supply 3 supplies current to the gradient coil 2 and the strength of the supplied current, and the strength and supply of the RF pulse signal that the transmission circuit 5 supplies to the WB coil 4. Information defining timing, detection timing at which the receiving circuit 7 detects the MR signal, and the like.

  The data collection function 15a receives MR signal data from the receiving circuit 7 as a result of executing various pulse sequences, and stores the received MR signal data in the storage circuit 13. The set of MR signal data received by the data acquisition function 15a is arranged two-dimensionally or three-dimensionally according to the position information given by the readout gradient magnetic field, phase encoding gradient magnetic field, and slice gradient magnetic field. Thus, the data is stored in the storage circuit 13 as data constituting the k space.

  The processing circuit 16 has an image generation function 16a. The image generation function 16 a generates an image based on the MR signal data stored in the storage circuit 13. Specifically, the image generation function 16a reads the MR signal data stored in the storage circuit 13 by the data collection function 15a, and performs post-processing, that is, reconstruction processing such as Fourier transform on the read MR signal data. To generate an image. In addition, the image generation function 16 a stores the image data of the generated image in the storage circuit 13.

  The processing circuit 17 performs overall control of the MRI apparatus 100 by controlling each component included in the MRI apparatus 100 based on an input operation received by the interface 11. For example, the processing circuit 17 receives an input of imaging conditions from the operator via the interface 11. Then, the processing circuit 17 generates sequence execution data based on the accepted imaging conditions, and transmits the sequence execution data to the processing circuit 15 to execute various pulse sequences. Further, for example, the processing circuit 17 reads out image data from the storage circuit 13 and outputs it to the display 12 in response to a request from the operator.

  Further, the processing circuit 17 has a positioning function 17a, a display control function 17b, and an imaging control function 17c. Here, the positioning function 17a is an example of a means for realizing the positioning unit. The display control function 17b is an example of a means for realizing a display control unit. The imaging control function 17c is an example of a means for realizing an imaging control unit. These functions will be described later in detail.

  For example, the processing circuits 14 to 17 described above are each realized by a processor. In this case, for example, the processing functions of each of the processing circuits 14 to 17 are stored in the storage circuit 13 in the form of a program that can be executed by a computer. Each processing circuit implements a function corresponding to each program by reading each program from the storage circuit 13 and executing it. In other words, each processing circuit in a state where each program is read has each function shown in each processing circuit of FIG. Here, although each processing function is described as being realized by a plurality of processors, a processing circuit may be configured by a single processor, and the functions may be realized by the processor executing a program. Absent. In addition, the processing functions of each processing circuit may be realized by being appropriately distributed or integrated into a single or a plurality of processing circuits. Further, here, a single storage circuit 13 has been described as storing a program corresponding to each processing function. However, a plurality of storage circuits are arranged in a distributed manner, and the processing circuits correspond to individual storage circuits. It may be configured to read the program.

  The overall configuration of the MRI apparatus 100 according to this embodiment has been described above. Under such a configuration, the MRI apparatus 100 according to the present embodiment has a function for confirming whether or not a cross section to be imaged is a desired cross section before performing the imaging.

  Specifically, the positioning function 17 a positions the region of interest on the subject positioning image displayed on the display 12. Further, the display control function 17b generates a reference image corresponding to the position of the region of interest based on the input image related to the subject and displays it on the display 12. Then, after the positioning of the region of interest is completed, the imaging control function 17c captures an image corresponding to the position of the region of interest in the subject.

  In such a function, it is required to display a reference image referred to in order to confirm the positioning of the region of interest more appropriately. For example, when displaying a reference image, it is required to secure an image quality that can recognize the anatomy, and to secure accurate position information.

  Therefore, in this embodiment, the display control function 17b selects an input image from at least one image related to the subject according to the purpose of imaging performed after the positioning of the region of interest is completed. Yes. Note that the purpose of imaging here includes a region to be imaged, a flow of an examination in which imaging is performed, and the like.

  Hereinafter, the function of the MRI apparatus 100 described above will be described in detail.

  FIG. 2 is a flowchart illustrating a processing procedure of processing performed by the MRI apparatus 100 according to the first embodiment. FIG. 3 is a diagram illustrating a display example of various images displayed by the MRI apparatus 100 according to the first embodiment.

  For example, as shown in FIG. 2, in this embodiment, first, the positioning function 17a displays a positioning image on the display 12 in accordance with an instruction from the operator received by the interface 11 (step S101).

  Specifically, the positioning function 17 a generates a positioning image based on the three-dimensional image data of the subject that has been imaged earlier in the same examination, and displays the generated positioning image on the display 12. The three-dimensional image data here may be volume data collected in a 3D sequence, or multi-slice data collected in a 2D sequence.

  For example, the positioning function 17a generates an MPR (Multi-Plane Reconstruction) image or a volume rendering image at a position and direction designated by the operator as a positioning image and displays it on the display 12. For example, as shown in FIG. 3, the positioning function 17 a generates a sagittal image 201 and an axial image 202 related to the same subject as the positioning image and displays them on the display 12.

  Subsequently, the positioning function 17a sets a region of interest on the positioning image displayed on the display 12 in accordance with an instruction from the operator received by the interface 11 (step S102).

  For example, as shown in FIG. 3, the positioning function 17a sets a region of interest on the sagittal image 201 displayed as a positioning image, and displays a rectangular graphic 203 indicating the position of the set region of interest. Similarly, the positioning function 17a displays a rectangular graphic 204 indicating a region of interest at a corresponding position in the axial image 202.

  Thereafter, the display control function 17b selects an input image from at least one image related to the subject according to the purpose of imaging performed after the positioning of the region of interest is completed (step S104).

  Specifically, the display control function 17b selects an input image according to a priority order determined in advance according to the purpose of imaging.

  For example, the display control function 17b displays on the display 12 the 3D image data of the subject that has been previously imaged in the same examination as the input image candidate. At this time, the display control function 17b displays the three-dimensional image data side by side in descending order of priority according to a priority determined in advance according to the purpose of imaging. The three-dimensional image data here may be volume data collected in a 3D sequence, or multi-slice data collected in a 2D sequence.

  For example, as illustrated in FIG. 3, the display control function 17 b displays one or more three-dimensional image data 205 of the same subject as thumbnails on the display 12 as input image candidates. Here, for example, the display control function 17b displays the three-dimensional image data 205 side by side in order from left to right in descending order of priority according to a priority determined in advance according to the purpose of imaging.

  At this time, the display control function 17b reads the three-dimensional image data of the subject that has been imaged earlier in the same examination from the storage circuit 13, and refers to the accompanying information attached to each read input image. The priority order of each image is determined. Here, the incidental information attached to the input image includes, for example, information indicating the imaging conditions (imaging parameters, etc.) used when the input image is captured, the region to be imaged, and the like.

  Then, the display control function 17b selects an image selected by the operator from the displayed candidates as an input image. Alternatively, the display control function 17b may automatically select the three-dimensional image with the highest priority as the input image from the three-dimensional image data of the subject that has been imaged earlier in the same examination. Here, the image selected as the input image may be the three-dimensional image data used for generating the positioning image, or may be another three-dimensional image data.

  Here, for example, when a specific part is imaged, the display control function 17b selects an image in which the specific part is most clearly depicted as an input image.

  As a specific example, for example, the display control function 17b can be used for blood flow and CSF (ASF (Arterial Spin Labeling) method, Time-Slip (Time-Spatial Labeling Inversion Pulse) method, PS Flow (Phase Shift Flow) method, etc. When imaging of cerebrospinal fluid (cerebrospinal fluid) is performed, an image in which blood flow is emphasized is preferentially selected as an input image from images captured in the preceding stage. In this case, for example, the display control function 17b is in the order of 3D-TOF (Time Of Flight) image> 3D-UTE (Ultrashort Echo Time) -ASL image> contrast 3D image> 2D-TOF image. Select a high image as the input image.

  For example, when imaging is performed in a specific cross-sectional direction, the display control function 17b selects an image having the highest resolution in the specific cross-sectional direction as an input image.

  As a specific example, for example, the display control function 17b preferentially selects an image having a high resolution in the axial direction as an input image when a T2-weighted image on the axial plane is captured. In this case, for example, the display control function 17b selects an image having a higher order as an input image in the order of 3D image> 2D image.

  Further, for example, when the moving subject is imaged, the display control function 17b selects an image related to the subject imaged at the nearest time point as the input image.

  As a specific example, for example, when imaging of a fetus is performed, the display control function 17b preferentially selects the same fetal image captured most recently as an input image. In this case, for example, the display control function 17b selects an image having a higher order as an input image in the order of an image picked up more recently> a higher resolution image.

  For example, the display control function 17b selects images of the same subject captured by different types of medical image diagnostic apparatuses (also called modalities) as input images.

  As specific examples, for example, an MR (Magnetic Resonance) image, a CT (Computed Tomography) image, a US (UltraSound) image, a PET (Positron Emission Tomography) / SPECT (Single Photon Emission Computed Tomography) image obtained by imaging the same subject. If there is an image, the display control function 17b selects an image with a higher order as an input image in the order of CT image> MR image> UL image when an image with higher resolution is required. Alternatively, the display control function 17b preferentially selects a function image such as a PET image as an input image when it is required to grasp the position of a lesion such as a tumor.

  Note that examples of input images selected by the display control function 17b are not limited to those described above. For example, the display control function 17b may select a subtraction image (difference image) as an input image when it is required to check a cross section of a tumor. For example, the display control function 17b may select three-dimensional image data (volume data or multi-slice data) of a quantitative map such as a WFS (Water Fat Separation) image as an input image. For example, when dynamic imaging or volume cine imaging is performed, the display control function 17b may select a contrast phase image in which a lesion is depicted as an input image. For example, the display control function 17b may select an image obtained by calculation, such as an image obtained by Synthetic MRI or MR fingerprinting, as the input image.

  As described above, by appropriately selecting the input image in accordance with the priority order determined in advance according to the purpose of imaging, it is possible to ensure the image quality that can be recognized by the anatomy when the reference image is displayed.

  Further, for example, the display control function 17b may appropriately select an input image depending on whether or not the imaging plan uses a distortion correction image.

  In this case, the display control function 17b determines whether the imaging plan uses a distortion correction image. Then, when the imaging plan is performed using the distortion correction image, the display control function 17b selects an image to which the gradient magnetic field distortion compensation processing is applied as the input image, and the imaging plan uses the distortion correction image. If not, an image to which the gradient magnetic field distortion compensation processing is not applied is selected as an input image. Here, for example, the gradient magnetic field distortion compensation processing is 3D-GDC (3 Dimension Gradient Distortion Correction) or the like.

  In general, when the imaging plan is executed, in order to secure the position information, the distortion correction image is consistently used throughout the inspection, or the distortion correction image is not consistently used. desirable. Therefore, by appropriately selecting an image to which the gradient magnetic field distortion compensation processing is applied or an image to which the gradient magnetic field distortion compensation processing is not applied as an input image depending on whether or not the imaging plan is performed using the distortion correction image, the reference image When displaying, accurate position information can be secured.

  Thus, after selecting the input image, the display control function 17b generates a reference image corresponding to the position of the region of interest positioned on the positioning image based on the input image (step S104) and displays it on the display 12. (Step S105).

  For example, as illustrated in FIG. 3, the display control function 17 b generates a MIP image 206 corresponding to the position of the region of interest positioned on the positioning image as a reference image and displays the MIP image 206 on the display 12. For example, the display control function 17b may generate an MPR (Maximum Intensity Projection) image or an SVR (Shaded Volume Rendering) image as the reference image.

  Thereafter, the positioning function 17a and the display control function 17b accept an operation for changing the region of interest from the operator via the interface 11 (step S106).

  For example, in the example illustrated in FIG. 3, the positioning function 17 a performs a rectangular graphic 203 displayed on the sagittal image 201 or a rectangular graphic displayed on the axial image 202 as an operation to change the region of interest. An operation for changing the position and the size of 204 is received. On the other hand, for example, the display control function 17b accepts an operation of enlarging or reducing the reference image by moving the cursor 208 on the slider 207 displayed on the display 12 as an operation of changing the region of interest. Here, for example, the size of the display area in which the reference image is displayed on the display 12 is fixed, and when the reference image is enlarged and displayed, the size of the region of interest is relatively small. When the reference image is reduced and displayed, the region of interest is relatively large.

  Then, when either one of the positioning function 17a and the display control function 17b receives an operation for changing the region of interest (Yes in step S106), the other region is also interlocked so as to correspond to the change. To change. That is, when one of the positioning function 17a and the display control function 17b accepts an operation for changing the region of interest, the positioning function 17a is displayed on the sagittal image 201 so as to indicate the region of interest after the change. The position and size of the rectangular graphic 203 and the rectangular graphic 204 displayed on the axial image 202 are changed, and the display control function 17b is enlarged or reduced so as to correspond to the changed region of interest. A reduced reference image is generated (step S104) and displayed on the display 12 (step S105).

  Here, when neither the positioning function 17a nor the display control function 17b accepts an operation for changing the region of interest (No in step S106), the display control function 17b changes the input image via the interface 11. An operation is accepted from the operator (step S107).

  For example, in the example illustrated in FIG. 3, the display control function 17 b receives an operation for selecting another image as an input image from the three-dimensional image data 205 displayed as a thumbnail on the display 12 from the operator.

  When the display control function 17b receives an operation for changing the input image (Yes in step S107), the display control function 17b newly generates a reference image based on the changed input image (step S104), and displays the display image. 12 (step S105).

  On the other hand, when neither the positioning function 17a nor the display control function 17b accepts an operation for changing the region of interest (No at Step S106) and the display control function 17b does not accept an operation for changing the input image (Step S106). (S107, No), the positioning function 17a receives an operation for changing the positioning image from the operator via the interface 11 (step S108).

  When the positioning function 17a receives an operation for changing the positioning image (step S108, Yes), the positioning function 17a displays a new positioning image on the display 12 (step S101).

  For example, the positioning function 17a generates a new positioning image on the display 12 based on the three-dimensional image data of the subject that has been previously captured in the same examination in accordance with an instruction from the operator. Alternatively, for example, the positioning function 17a displays the reference image displayed at that time on the display 12 as a new positioning image.

  Thereafter, the above-described processing is similarly performed until the imaging control function 17c receives an instruction to the effect that the region of interest has been positioned from the operator via the interface 11. When the imaging control function 17c receives an instruction from the operator that the region of interest has been positioned (step S109, Yes), the image corresponding to the position of the region of interest set at that time is displayed. Imaging is executed (step S110).

  Specifically, the imaging control function 17c generates sequence execution data for collecting MR signal data corresponding to the position of the region of interest, and transmits the sequence execution data to the processing circuit 15, whereby the data collection function 15a of the processing circuit 15 is obtained. Causes the pulse sequence to be executed. In addition, the imaging control function 17c causes the image generation function 16a of the processing circuit 16 to generate an image based on the data collected by the data collection function 15a of the processing circuit 15, thereby generating an image corresponding to the position of the region of interest. Take an image.

  Of the steps described above, steps S101, S102, S106, and S108 are realized, for example, when the processing circuit 17 reads a predetermined program corresponding to the positioning function 17a from the storage circuit 13 and executes it. Steps S103 to S107 are realized, for example, when the processing circuit 17 reads a predetermined program corresponding to the display control function 17b from the storage circuit 13 and executes it. Steps S109 and S110 are realized, for example, when the processing circuit 17 reads a predetermined program corresponding to the imaging control function 17c from the storage circuit 13 and executes it.

  As described above, in the first embodiment, the display control function 17b selects the input image according to the purpose of imaging performed after the positioning of the region of interest is completed, thereby confirming the positioning of the region of interest. The reference image referred to can be displayed more appropriately. For example, when displaying a reference image, it is possible to ensure image quality that can be recognized by anatomy, and to ensure accurate position information.

  Then, by appropriately displaying the reference image in this way, it is possible to avoid a decrease in the clinical value of the examination image obtained by the MRI apparatus 100. In addition, it is possible to avoid erroneous determination that may occur when an imaging cross section is confirmed with an inappropriate reference image. In addition, it is possible to avoid extending the inspection time due to re-imaging when there is an erroneous determination or the like. Further, it is possible to save time and effort for selecting an input image used for generating a reference image.

  In the above-described embodiment, the priority order of images is determined in advance according to the purpose of imaging, but the embodiment is not limited thereto. For example, the priority order may be learned based on the history of input images actually selected by the operator.

  In this case, for example, information indicating the priority order for each purpose of imaging is stored in the storage circuit 13, and the display control function 17b responds to the selection result each time an input image is selected by the operator. To update the stored priority. Alternatively, every time an input image is selected by the operator, the display control function 17b accumulates information indicating the image selected as the input image in the storage circuit 13, and is stored in the storage circuit 13 by night batch or the like. Update the priority. As a result, the priority order of images to be input images can be optimized in accordance with the result of selection actually performed by the operator.

(Second Embodiment)
In the first embodiment described above, an example in which an input image is selected from three-dimensional image data of a subject that has been imaged earlier in the same examination has been described. However, the embodiment is not limited thereto. . For example, when there is a past image obtained by imaging the same subject, an input image may be selected from the past image. Hereinafter, such an example will be described as a second embodiment. The second embodiment will be described with a focus on differences from the first embodiment, and components that play the same role as the components already described will be described with the same reference numerals. Is omitted.

  Specifically, in the present embodiment, the display control function 18b targets the past image obtained by imaging the same subject in addition to the three-dimensional image data of the subject previously captured by the same examination as the input image. Select.

  Here, past images obtained by imaging the same subject may include images taken by other medical image diagnostic apparatuses such as CT images, UL images, and PET / SPECT images. For example, when a CT image or a UL image is captured in the previous examination, a reference image can be generated using a higher-detailed image by selecting those images as input images. In addition, for example, when a functional image such as a PET / SPECT image is captured in the previous examination, by selecting the image as an input image, it is possible to grasp the state of the tumor and metabolism on the reference image. Become.

  As described above, when selecting a past image obtained by imaging the same subject as the input image, the display control function 17b positions the input image in the image previously captured in the examination being performed. Use together.

  At this time, for example, the display control function 17b uses a known registration method to align the past image with the image previously captured during the examination being performed. For example, the display control function 17b detects an anatomical feature point from each image by landmark detection technology, template matching using a brain map such as Atlas, machine learning, and the like, and the detected feature point is detected. As a reference, image alignment is performed.

  FIG. 4 is a diagram illustrating an example of image alignment performed by the MRI apparatus 100 according to the second embodiment.

  For example, as illustrated in FIG. 4, when there is a past image 301 such as a high-detail 3D image or a functional image related to the same subject, the display control function 17 b has captured the past image 301 by non-rigid deformation in the same examination. A past image 303 aligned with the coarse MR image is generated. Then, the display control function 17b selects the aligned past image 303 as an input image.

  As described above, in the second embodiment, by selecting a past image obtained by imaging the same subject as an input image, a more appropriate reference image according to the purpose of the examination can be presented. .

  In each of the above-described embodiments, an example in which the positioning unit, the display control unit, and the imaging control unit in this specification are realized by the positioning function 17a, the display control function 17b, and the imaging control function 17c of the processing circuit 17. Although described, the embodiment is not limited to this. For example, the positioning unit, the display control unit, and the imaging control unit in this specification are realized by the positioning function 17a, the display control function 17b, and the imaging control function 17c described in the embodiment, and are only hardware or software only. Alternatively, the same function may be realized by mixing hardware and software.

  The term “processor” used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an application specific integrated circuit (ASIC), or a programmable logic device. (For example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). Instead of storing the program in the storage circuit, the program may be directly incorporated in the processor circuit. In this case, the processor realizes the function by reading and executing the program incorporated in the circuit. In addition, each processor of the present embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining a plurality of independent circuits to realize its function. Good. Furthermore, a plurality of components shown in FIG. 1 may be integrated into one processor to realize the function.

  Here, the program executed by the processor is provided by being incorporated in advance in a ROM (Read Only Memory), a storage circuit, or the like, for example. This program is a file in a format installable or executable in these devices, and is a computer such as a CD (Compact Disk) -ROM, FD (Flexible Disk), CD-R (Recordable), DVD (Digital Versatile Disk), etc. And may be provided by being recorded on a storage medium readable by the computer. The program may be provided or distributed by being stored on a computer connected to a network such as the Internet and downloaded via the network. For example, this program is composed of modules including the above-described functional units. As actual hardware, the CPU reads a program from a storage medium such as a ROM and executes it, whereby each module is loaded on the main storage device and generated on the main storage device.

  According to at least one embodiment described above, it is possible to more appropriately display the reference image that is referred to in order to confirm the positioning of the region of interest.

  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 100 Magnetic Resonance Imaging (MRI) apparatus 17 Processing circuit 17a Positioning function 17b Display control function 17c Imaging control function

Claims (8)

A positioning unit for positioning the region of interest on the positioning image of the subject displayed on the display unit;
A display control unit that generates a reference image corresponding to the position of the region of interest based on an input image related to the subject and displays the reference image on the display unit;
An imaging control unit that captures an image corresponding to the position of the region of interest in the subject after positioning of the region of interest is completed;
The display control unit selects the input image from at least one image related to the subject according to the purpose of imaging performed after the positioning of the region of interest is completed.
Magnetic resonance imaging device. The display control unit selects the input image according to a priority order determined in advance according to the purpose of the imaging;
The magnetic resonance imaging apparatus according to claim 1. The display control unit selects, as the input image, an image in which the specific part is most clearly depicted when imaging of the specific part is performed.
The magnetic resonance imaging apparatus according to claim 1 or 2. The display control unit selects an image having the highest resolution in the specific cross-sectional direction as the input image when imaging is performed in the specific cross-sectional direction.
The magnetic resonance imaging apparatus according to any one of claims 1 to 3. The display control unit selects, as the input image, an image related to the subject imaged at the nearest time point when the moving subject is imaged.
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. The display control unit selects, as the input image, an image of the same subject captured by different types of medical image diagnostic apparatuses;
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. When the imaging plan is performed using a distortion correction image, the display control unit selects an image to which gradient magnetic field distortion compensation processing is applied as the input image, and the imaging plan uses the distortion correction image. If not, select an image to which the gradient magnetic field distortion compensation processing is not applied as the input image.
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. When the display control unit selects a past image obtained by imaging the subject as the input image, the input control image is used by aligning the input image with an image previously captured in an examination being performed.
The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus.

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