JP7106291B2 - Magnetic resonance imaging system - Google Patents

Description

Embodiments of the present invention relate to magnetic resonance imaging apparatus.

Conventionally, in a Magnetic Resonance Imaging (MRI) apparatus, when imaging a subject, an image of the same subject that has already been imaged is used as a positioning image to position a region of interest to be imaged. It has been known.

JP 2010-000144 A JP 2012-115635 A WO2012/074039

The problem to be solved by the present invention is to better display the reference image that is referenced to confirm the positioning of the region of interest.

A magnetic resonance imaging apparatus according to an embodiment includes a positioning section, a display control section, and an imaging control section. The positioning unit positions the 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 the input image of 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 positioning of the region of interest is completed. The display control unit varies image processing to be performed when generating the reference image according to the input image.

FIG. 1 is a diagram showing a configuration example of an MRI apparatus according to the first embodiment. FIG. 2 is a flow chart showing the procedure of processing performed by the MRI apparatus according to the first embodiment. FIG. 3 is a diagram showing display examples of various images displayed by the MRI apparatus according to the first embodiment. FIG. 4 is a diagram showing an example of annotation display performed by the MRI apparatus according to the second embodiment.

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

(First embodiment)
FIG. 1 is a diagram showing 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 supply 3, a whole body (WB) coil 4, a transmission circuit 5, a local coil 6, a receiving circuit 7, an RF shield 8, a pedestal 9, a bed 10, an interface 11, a display 12, a memory circuit 13, and processing circuits 14-17.

The static magnetic field magnet 1 generates a static magnetic field in an imaging space in which the subject S is imaged. Specifically, the static magnetic field magnet 1 is formed in a hollow, substantially cylindrical shape (including one having an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and an imaging space arranged in the cylinder. to generate a static magnetic field. For example, the static magnetic field magnet 1 has a substantially cylindrical cooling container 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 use a permanent magnet to generate a static magnetic field.

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

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

In this way, the gradient magnetic field power supply 3 generates gradient magnetic fields along the respective axial directions of the X-axis, the Y-axis and the Z-axis. can be generated. Axes along the readout direction, the phase encoding direction, and the slice direction constitute a logical coordinate system for defining a slice region or volume region to be imaged. Hereinafter, the gradient magnetic field along the readout direction is called the readout gradient magnetic field, the gradient magnetic field along the phase encode direction is called the phase encode gradient magnetic field, and the gradient magnetic field along the slice direction is called the slice gradient magnetic field. .

Each gradient magnetic field is superimposed on the 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. FIG. Specifically, the readout gradient magnetic field changes the frequency of the MR signal according to the position in the readout direction, thereby imparting positional information along the readout direction to the MR signal. Also, the phase-encoding gradient magnetic field changes the phase of the MR signal along the phase-encoding direction, thereby imparting positional information in the phase-encoding direction to the MR signal. In addition, the slice gradient magnetic field imparts positional information along the slice direction to the MR signal. For example, if the imaging region is a slice region, the slice gradient magnetic field is used to determine the direction, thickness, and number of slice regions. is used to change the phase of the MR signal.

The WB coil 4 is arranged 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 MR generated from the subject S due to the influence of the RF magnetic field. It is an RF coil that has the function of a receiving coil for receiving signals. Specifically, the WB coil 4 is formed in a hollow, substantially cylindrical shape (including one having an elliptical cross section perpendicular to the central axis of the cylinder), and the RF pulse supplied from the transmission circuit 5 is Based on the signal, an RF magnetic field is applied to an imaging volume located within the cylinder. The WB coil 4 also receives MR signals generated from the subject S under the influence of the RF magnetic field, and outputs the received MR signals 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 (radio frequency) signal at a resonance frequency (Larmor frequency) unique to the nuclei of interest placed in a static magnetic field. A phase selector selects the phase of the RF wave signal. A 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 sinc function waveform. The RF amplifier power-amplifies the RF pulse signal output from the amplitude modulator and outputs it to the WB coil 4 .

The local coil 6 is an RF coil having the function of a receiving coil for receiving MR signals generated from the subject S. Specifically, the local coil 6 is attached to the subject S placed inside the WB coil 4, receives MR signals generated from the subject S under the influence of the RF magnetic field applied by the WB coil 4, It outputs the received MR signal to the receiving circuit 7 . For example, the local coils 6 are receiving coils prepared for each region to be imaged, such as 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. These include receiving coils, receiving coils for the lower extremities, receiving coils for the spine, and the like. Note that the local coil 6 may further have the function of a transmission coil that applies an RF magnetic field to the subject S. In that 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 preamplifier, 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 preamplifier power-amplifies the MR signal output from the selector. The phase detector detects the phase of the MR signal output from the preamplifier. The A/D converter converts the analog signal output from the phase detector into a digital signal to generate MR signal data, and outputs the generated MR signal data to the processing circuit 15 .

The RF shield 8 is arranged between the gradient coil 2 and the WB coil 4 and shields the gradient 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 one having an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and the inner peripheral side of the gradient magnetic field coil 2 It is arranged in the space so as to cover the outer peripheral surface of the WB coil 4 .

A pedestal 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 frame 9 has a hollow bore B formed in a substantially cylindrical shape, and surrounds the bore B with a static magnetic field magnet 1, a gradient magnetic field coil 2, a WB coil 4, and an RF shield 8. Each is accommodated in the arranged state. Here, the space inside the bore B of the gantry 9 serves as 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 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 configuration in which a pair of static magnetic field magnets, a pair of gradient magnetic field coils, and a pair of RF coils are arranged to face each other across an imaging space in which the subject S is arranged. You may have

The bed 10 has a tabletop 10a on which the subject S is placed. For example, the bed 10 is installed so that its 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 electric signal, and outputs the electric signal to the processing circuit 17 . For example, the interface 11 includes a trackball, a switch button, a mouse, a keyboard, a touch pad for performing input operations by touching the operation surface, a display screen, and the like for setting imaging conditions and regions of interest (ROI). It is realized by a touch screen integrated with a touch pad, a non-contact input circuit using an optical sensor, an audio input circuit, and the like. In this specification, the interface 11 is not limited to having physical operation parts such as a mouse and a keyboard. For example, the interface 11 also includes an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to the control circuit. Note that the interface 11 is an example of means for implementing 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 image data sent from the processing circuit 17 into electrical signals for display, and outputs the electrical signals. For example, the display 12 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, or the like. Note that the display 12 is an example of means for realizing the 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 implemented by a semiconductor memory device such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, or the like. Note that the storage circuit 13 is an example of a means for realizing a storage unit.

The processing circuit 14 has a bed control function 14a. The bed control function 14 a is connected to the bed 10 and outputs control electric signals to the bed 10 to control the operation of the bed 10 . For example, the bed control function 14a receives an instruction from the operator via the interface 11 to move the tabletop 10a in the longitudinal direction, the vertical direction, or the horizontal direction, and controls the bed so as to move the tabletop 10a according to the received instruction. The drive mechanism of the top plate 10a of 10 is operated.

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

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

The data acquisition function 15 a 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 positional information given by the readout gradient magnetic field, the phase-encoding gradient magnetic field, and the slice gradient magnetic field. Thus, it is stored in the storage circuit 13 as data forming 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 memory 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 the image. Further, the image generation function 16a causes the storage circuit 13 to store the image data of the generated image.

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

The processing circuit 17 also 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 means for realizing the positioning unit. Also, the display control function 17b is an example of means for realizing the display control unit. Also, the imaging control function 17c is an example of means for realizing the imaging control unit. Note that these functions will be described later in detail.

For example, the processing circuits 14 to 17 described above are each implemented by a processor. In this case, for example, the processing functions of the processing circuits 14 to 17 are stored in the storage circuit 13 in the form of programs executable by a computer. Each processing circuit reads each program from the storage circuit 13 and executes it, thereby realizing a function corresponding to each program. In other words, each processing circuit with each program read has each function shown in each processing circuit in FIG. Here, although each processing function is implemented by a plurality of processors, the processing circuit may be configured by a single processor, and the functions may be implemented by the processor executing a program. do not have. Also, the processing functions of each processing circuit may be appropriately distributed or integrated in a single or a plurality of processing circuits. Also, although the single memory circuit 13 stores the programs corresponding to the respective processing functions here, a plurality of memory circuits may be distributed and arranged so that the processing circuits correspond to the individual memory circuits. A configuration for reading a program may be used.

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

Specifically, the positioning function 17 a positions the region of interest on the positioning image of the subject displayed on the display 12 . Also, the display control function 17 b generates a reference image corresponding to the position of the region of interest based on the input image of the subject and displays it on the display 12 . 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.

Such functionality requires a better display of the reference image that is referenced to confirm the positioning of the region of interest. For example, when displaying a reference image, it is required to ensure an image quality that enables recognition of the anatomy, to ensure accurate position information, to ensure agile movement, and the like.

For this reason, in the present embodiment, the display control function 17b varies the image processing performed when generating the reference image according to the input image. Note that the image processing here includes not only processing performed on generated images, but also processing performed to generate images, such as rendering processing.

The functions of the MRI apparatus 100 described above will be described in detail below.

FIG. 2 is a flowchart showing the procedure of processing performed by the MRI apparatus 100 according to the first embodiment. FIG. 3 is a diagram showing display examples 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 operator's instruction accepted by the interface 11 (step S101).

Specifically, the positioning function 17a generates a positioning image based on the three-dimensional image data of the subject previously imaged in the same examination, and displays the generated positioning image on the display 12. FIG. The three-dimensional image data referred to here may be volume data acquired in a 3D sequence, or may be multi-slice data acquired in a 2D sequence.

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

Subsequently, the positioning function 17a sets a region of interest on the positioning image displayed on the display 12 according to the operator's instruction received by the interface 11 (step S102).

For example, as shown in FIG. 3, the positioning function 17a sets a region of interest on a 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 the region of interest at the corresponding position in the axial image 202 as well.

After that, the display control function 17b selects an input image used for generating a reference image according to an instruction from the operator accepted by the interface 11 (step S103).

Specifically, the display control function 17b displays the three-dimensional image data of the subject previously imaged in the same examination on the display 12 as input image candidates, and the operator selects from the displayed candidates. Select an image as the input image. The three-dimensional image data referred to here may be volume data acquired in a 3D sequence, or may be multi-slice data acquired in a 2D sequence. Also, the image selected as the input image here may be the three-dimensional image data used to generate the positioning image, or may be another three-dimensional image data.

For example, as shown in FIG. 3, the display control function 17b displays thumbnails of one or more three-dimensional image data 205 of the same subject on the display 12 as input image candidates. Then, the display control function 17b selects an image selected by the operator from the thumbnail-displayed three-dimensional image data 205 as an input image.

After that, the display control function 17b determines image processing to be performed when generating the reference image according to the selected input image (step S104).

Specifically, the display control function 17b reads out the selected input image from the storage circuit 13, refers to additional information attached to the read input image, and determines appropriate image processing. Here, the supplementary information attached to the input image includes, for example, information indicating the imaging conditions (imaging parameters, etc.) used when the input image was captured, the region of the imaging target, and the like.

For example, the display control function 17b changes the rendering processing mode for generating the reference image according to the input image.

As a specific example, for example, the display control function 17b automatically selects which of MPR, MIP (Maximum Intensity Projection), and SVR (Shaded Volume Rendering) modes should be used for rendering processing.

For example, the display control function 17b controls that the input image is MRA (Magnetic Resonance Angiography) by a TOF (Time Of Flight) method, ASL (Arterial Spin Labeling) method, Time-Slip (Time-Spatial Labeling Inversion Pulse) method, or the like. imaging), MRCP (Magnetic Resonance Cholangio Pancreatography), or CSF (Cerebrospinal Fluid) imaging, rendering processing is performed in MIP mode. Further, the display control function 17b performs rendering processing in SVR mode when the input image is an image of an aneurysm in the head, chest, abdomen, or the like. If the input image is an image other than these images, the display control function 17b performs rendering processing in the MPR mode.

In this way, by appropriately changing the rendering processing mode according to the input image, it is possible to ensure an image quality that allows the anatomy to be recognized when the reference image is displayed.

Also, for example, the display control function 17b determines whether or not to execute at least one of image interpolation processing, resolution adjustment processing, and gradient magnetic field distortion compensation processing according to the input image. Then, the display control function 17b performs at least one of image interpolation processing, resolution adjustment processing, and gradient magnetic field distortion compensation processing according to the input image.

For example, the display control function 17b determines whether it is necessary to perform image interpolation processing according to the input image. As a specific example, for example, the display control function 17b performs interpolation processing such as Nearest Neighbor interpolation, linear interpolation, and bicubic interpolation as image interpolation processing.

Also, for example, the display control function 17b determines whether super-resolution processing needs to be executed according to the input image. As a specific example, for example, the display control function 17b performs filter processing such as unsharp masking as super-resolution processing.

In this case, for example, the display control function 17b determines whether it is necessary to perform image interpolation processing and resolution adjustment processing according to the resolution of the input image.

As a specific example, for example, when the input image is a gapless image acquired in a 3D sequence, a high spatial resolution image, or an isotropic voxel image, the display control function 17b is high resolution. Also, for example, if the input image is an image containing gaps acquired in a 2D sequence for the purpose of eliminating the effects of body movement or fetal movement or for analysis purposes, the input image has a low resolution. I judge. Alternatively, for example, the display control function 17b determines that the resolution of the input image is high when it is higher than the first threshold, and is low when it is equal to or lower than the second threshold, which is lower than the first threshold. Otherwise, it may be determined that the resolution is middle resolution.

Then, for example, as shown in the table below, the display control function 17b applies neither interpolation processing nor filtering processing when the input image has a high resolution, and applies interpolation processing when the input image has a medium resolution. Only filter processing is applied without processing, and if the resolution is low, both interpolation processing and filter processing are applied.

In this way, by appropriately determining whether or not to perform image interpolation processing and resolution adjustment processing, it is possible to reduce the load of image processing when displaying a reference image, thereby ensuring smooth operation. be able to

Note that, for example, the display control function 17b displays the reference image instead of performing the above-described image interpolation processing and resolution adjustment processing for high detail when the input image is selected. You may make it perform at the predetermined timing after it carries out. For example, the display control function 17b may perform processing for increasing detail at the timing when an operation to enlarge and display a reference image is performed. As a result, only when the enlarged display causes the reference image to be blurred, processing for increasing the detail is performed, and the load of image processing can be further reduced.

Further, for example, the display control function 17b preliminarily sets an upper limit to the processing speed or processing time for processing that can cause a high load, such as the above-described image interpolation processing and resolution adjustment processing. It is also possible not to perform processing with a large amount of calculation. This makes it possible to further reduce the image processing load.

Also, for example, the display control function 17b determines whether or not 3D-GDC (3 Dimensional Gradient Distortion Correction: 3D gradient magnetic field distortion compensation processing) needs to be executed according to the input image. For example, the display control function 17b executes 3D-GDC as preprocessing for rendering when an imaging plan is implemented using a distortion-corrected image. On the other hand, when the imaging plan is implemented using the image without distortion correction, the display control function 17b performs the 3D-GDC when the imaging plan is implemented using the distortion corrected image. don't run

In general, to ensure positional information when the imaging plan is performed, it is desirable to consistently use the dewarped image or not to use the dewarped image consistently throughout the examination. desirable. Therefore, by appropriately determining whether or not the gradient magnetic field distortion compensation process needs to be executed according to the input image, accurate position information can be secured when displaying the reference image.

In this way, after determining the image processing to be performed when generating the reference image, the display control function 17b performs the determined image processing so that the position of the region of interest positioned on the positioning image is displayed based on the input image. A corresponding reference image is generated (step S105) and displayed on the display 12 (step S106).

For example, as shown in FIG. 3, the display control function 17b generates a MIP image 206 corresponding to the position of the region of interest positioned on the positioning image and displays it on the display 12 as a reference image. Here, as the reference image, an MPR image or an SVR image may be generated according to the rendering processing mode determined according to the input image.

After that, the positioning function 17a and the display control function 17b receive an operation to change the region of interest from the operator via the interface 11 (step S107).

For example, in the example shown in FIG. 3, the positioning function 17a operates to change the region of interest by using a rectangular graphic 203 displayed on the sagittal image 201 or a rectangular graphic displayed on the axial image 202. It accepts an operation to change the position and size of 204 . On the other hand, for example, the display control function 17b accepts an operation to enlarge or reduce the reference image by moving the cursor 208 on the slider 207 displayed on the display 12 as an operation to change 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 assumed to be fixed, and when the reference image is enlarged and displayed, the size of the area of interest becomes relatively small, It is assumed that when the reference image is displayed in reduced size, the region of interest becomes relatively large.

Then, when one of the positioning function 17a and the display control function 17b receives an operation to change the region of interest (step S107, Yes), the other also interlocks to change the region of interest so as to correspond to the change. to change That is, when one of the positioning function 17a and the display control function 17b receives an operation to change the region of interest, the positioning function 17a is displayed on the sagittal image 201 so as to show the changed region of interest. The position and size of the rectangular graphic 203 displayed on the axial image 202 and the rectangular graphic 204 displayed on the axial image 202 are changed. A reduced reference image is generated (step S105) and displayed on the display 12 (step S106).

Here, when neither the positioning function 17a nor the display control function 17b accepts an operation to change the region of interest (step S107, No), the display control function 17b changes the input image via the interface 11. An operation is accepted from the operator (step S108).

For example, in the example shown in FIG. 3, the display control function 17b receives an operation from the operator to select another three-dimensional image data from among the three-dimensional image data 205 thumbnail-displayed on the display 12 as an input image.

When the display control function 17b receives an operation to change the input image (step S108, Yes), the display control function 17b determines the image processing to be performed when generating the reference image according to the changed input image ( Step S104), a new reference image is generated (step S105), and displayed on the display 12 (step S106).

On the other hand, when neither the positioning function 17a nor the display control function 17b receives an operation to change the region of interest (step S107, No) and the display control function 17b does not receive an operation to change the input image (step S108, No), the positioning function 17a receives an operation to change the positioning image from the operator via the interface 11 (step S109).

When the positioning function 17a receives an operation to change the positioning image (step S109, Yes), the positioning function 17a generates a new positioning image specified by the operator and displays it on the display 12 (step S101).

For example, the positioning function 17a generates a new positioning image and displays it on the display 12 in response to an instruction from the operator, based on the three-dimensional image data of the subject previously imaged in the same examination. Alternatively, for example, the positioning function 17a displays the reference image displayed at that time on the display 12 as a new positioning image.

After that, until the imaging control function 17c receives an instruction from the operator via the interface 11 to the effect that the positioning of the region of interest has been completed, the above-described processing is performed in the same manner. Then, when the imaging control function 17c receives an instruction from the operator to the effect that the positioning of the region of interest has been completed (step S110, Yes), the image corresponding to the position of the region of interest set at that time is reproduced. Imaging is performed (step S111).

Specifically, the imaging control function 17c generates sequence execution data for acquiring MR signal data corresponding to the position of the region of interest, and transmits it to the processing circuit 15, so that the data acquisition function 15a of the processing circuit 15 to execute the pulse sequence. The imaging control function 17c also 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.

Among the steps described above, steps S101, S102, S107 and S109 are realized, for example, by the processing circuit 17 reading out a predetermined program corresponding to the positioning function 17a from the storage circuit 13 and executing it. Further, steps S103 to S108 are realized, for example, by the processing circuit 17 reading out a predetermined program corresponding to the display control function 17b from the storage circuit 13 and executing it. Further, steps S110 and S111 are realized by, for example, the processing circuit 17 reading out a predetermined program corresponding to the imaging control function 17c from the storage circuit 13 and executing it.

As described above, in the first embodiment, the display control function 17b changes the image processing to be performed when generating the reference image according to the input image, thereby making the reference image for confirming the positioning of the region of interest. The reference image to be displayed can be displayed more appropriately. For example, when displaying a reference image, it is possible to ensure an image quality that allows anatomy to be recognized, to ensure accurate position information, and to ensure agile movement.

By appropriately displaying the reference image in this way, it is possible to avoid the deterioration of the clinical value of the examination image obtained by the MRI apparatus 100 . In addition, it is possible to avoid misjudgment that may occur when an imaging section is confirmed using an inappropriately displayed reference image. Further, it is possible to avoid extension of inspection time due to redoing imaging when an erroneous determination is made. In addition, it is possible to save time and labor for setting the display conditions of the reference image.

(Second embodiment)
Note that the function for confirming whether or not the cross section to be imaged is the desired cross section before imaging, as described in the above-described first embodiment, furthermore, when displaying the reference image, Assistance in comprehending anatomy may also be required. Therefore, for example, in the MRI apparatus 100 according to the first embodiment, information indicating tissues detected by anatomical feature analysis may be superimposed on the reference image. Such an example will be described below as a second embodiment. In the second embodiment, differences from the first embodiment will be mainly described. Constituent elements that play the same role as the constituent elements already described are denoted by the same reference numerals, and detailed description will be given. is omitted.

Specifically, in the present embodiment, the display control function 17b detects anatomical feature points in the image of the subject to identify the tissue included in the reference image, and generates information indicating the identified tissue. Display superimposed on the reference image.

For example, the display control function 17b detects feature points from the input image used to generate the reference image, and identifies tissue based on the detected feature points. At this time, for example, the display control function 17b analyzes the image of the subject using a landmark detection technology for detecting anatomical feature points, thereby detecting organs, muscles, ligaments, tendons, bones, etc. identify the organization of Alternatively, the display control function 17b may specify the tissue by analyzing the image of the subject by template matching using a brain map such as Atlas, machine learning, or the like.

Note that, for example, the display control function 17b individually detects detectable feature points from each of a plurality of captured images of the same subject, aligns the images, and integrates the detected feature points. You may Note that the display control function 17b may detect feature points by further using a reference image generated by image processing in addition to the input image and the captured image.

Here, even if the captured images of the same subject include images captured by other medical image diagnostic apparatuses (also called modalities), such as CT images, UL images, and PET/SPECT images, good. For example, by using images with higher resolution than MR images, such as CT images and UL images, feature points that cannot be detected from MR images can be detected, and tissues can be identified in more detail. .

When displaying the reference image, the display control function 17b superimposes information indicating the specified tissue on the reference image.

FIG. 4 is a diagram showing an example of annotation display performed by the MRI apparatus 100 according to the second embodiment.

For example, as shown in FIG. 4, when the MIP image 206 is displayed as a reference image, the display control function 17b selects tissue names such as "corpus callosum", "lateral ventricle", "frontal lobe", and "occipital lobe". is displayed as an annotation on the MIP image 206 .

Here, for example, when a plurality of images are used, the display control function 17b may, after detecting feature points from all images, collectively display information indicating tissue at the timing of displaying a reference image. Alternatively, after the reference image is displayed, feature points may be detected from each image by background processing, and information indicating the tissue may be displayed in order from the detected feature points.

In addition, for example, the display control function 17b stores the detection results of the feature points detected from each image in association with each image individually, and when the same image is used later, the stored detection results are stored. You may make it use a result.

As described above, in the second embodiment, by superimposing the information indicating the tissue detected by the anatomical feature analysis on the reference image, it is possible to assist understanding of the anatomy when displaying the reference image. be able to

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

In addition, 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), a programmable logic device (eg, Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). Instead of storing the program in the memory circuit, the program may be directly incorporated in the circuit of the processor. In this case, the processor implements its functions by reading and executing the program embedded in the circuit. Further, each processor of the present embodiment is not limited to being configured as a single circuit for each processor, but may be configured as one processor by combining a plurality of independent circuits to realize its function. good. Furthermore, a plurality of components in FIG. 1 may be integrated into one processor to realize its functions.

Here, the program to be executed by the processor is provided by being pre-installed in, for example, a ROM (Read Only Memory), a storage circuit, or the like. This program is a file in a format that can be installed in these devices or in a format that can be executed. may be recorded in a readable storage medium and provided. Also, this 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 each functional unit described above. As actual hardware, the CPU reads out a program from a storage medium such as a ROM and executes it, so that each module is loaded onto the main storage device and generated on the main storage device.

According to at least one of the embodiments described above, it is possible to more appropriately display the reference image referred to for confirming the positioning of the region of interest.

While several embodiments of the invention have been described, these embodiments have been 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 modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

100 magnetic resonance imaging (MRI) apparatus 17 processing circuit 17a positioning function 17b display control function 17c imaging control function

Claims (5)

a positioning unit that positions the region of interest on the positioning image of the subject displayed on the display unit;
A reference image corresponding to the position of the region of interest is generated by performing image processing on an input image that is a captured image of the subject or on an image generated from the input image. a display control unit for displaying on the display unit by
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 varies the image processing performed when generating the reference image according to the imaging conditions used when the input image was captured.
Magnetic resonance imaging equipment. The display control unit is required to execute at least one of image interpolation processing, resolution adjustment processing, and gradient magnetic field distortion compensation processing according to imaging conditions used when the input image was captured. determine no,
The magnetic resonance imaging apparatus according to claim 1. The display control unit performs at least one of image interpolation processing, resolution adjustment processing, and gradient magnetic field distortion compensation processing according to the imaging conditions used when the input image was captured.
3. The magnetic resonance imaging apparatus according to claim 1 or 2. The display control unit detects an anatomical feature point from at least one of the input image, another captured image of the subject, and the reference image, thereby detecting tissue included in the reference image. and displaying information indicating the identified tissue superimposed on the reference image;
The magnetic resonance imaging apparatus according to any one of claims 1-3. The display control unit changes a mode of rendering processing for generating the reference image according to imaging conditions used when the input image was captured.
The magnetic resonance imaging apparatus according to any one of claims 1-4.

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