JP6943663B2 - Magnetic resonance imaging device and image processing device - Google Patents

Description

Embodiments of the present invention relate to magnetic resonance imaging devices and image processing devices.

Magnetic resonance imaging (MRI) magnetically excites the nuclear spins of a subject placed in a static magnetic field with RF (Radio Frequency) pulses of Larmor Frequency, and is accompanied by this excitation. This is an imaging method in which an image is reconstructed from an NMR (Nuclear Magnetic Resonance) signal generated.

For example, in the case of a cardiac examination in magnetic resonance imaging, a reference cross section, which is a cross section based on the anatomical features of the heart, is set prior to imaging for diagnosis. Further, in magnetic resonance imaging, various imaging parameters such as FOV (Field Of View), number of phase encodes, number of slices, and acceleration rate of parallel imaging (Parallel Imaging) are set prior to imaging for diagnosis. ..

As a method of these settings, for example, there is a method of setting by displaying the morphological information of the cross-sectional position on the display unit (display) prior to the imaging for diagnosis.

However, for example, in the case of an inexperienced radiological technologist, imaging for diagnosis may be performed without considering the image quality, and imaging may be required again due to poor image quality.

Japanese Unexamined Patent Publication No. 62-270143 Japanese Unexamined Patent Publication No. 2009-45274 Japanese Unexamined Patent Publication No. 6-189935 Japanese Patent No. 5323194

An embodiment of the present invention provides a magnetic resonance imaging apparatus and an image processing apparatus capable of confirming information on image quality.

The magnetic resonance imaging apparatus according to the embodiment includes an imaging unit, an estimation unit, and a control unit. The imaging unit executes a first imaging and a second imaging after the first imaging on the subject. The estimation unit estimates information on the image quality when the second imaging is performed based on the magnetic resonance image related to the first imaging and the imaging conditions set for the second imaging. The control unit superimposes the estimation result on the magnetic resonance image and displays it on the display unit, receives a designated operation for the magnetic resonance image from the operator, and based on the designated operation, determines the imaging conditions related to the second imaging. Change the settings.

FIG. 1 is a diagram showing a magnetic resonance imaging apparatus according to an embodiment. FIG. 2 is a flowchart showing a procedure of processing performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 3 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 4 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 5 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 6 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 7 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 8 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 9 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 10 is a diagram illustrating a process performed by the magnetic resonance imaging apparatus according to the embodiment. FIG. 11 is a diagram illustrating a hardware configuration of the image processing device according to the embodiment.

Hereinafter, the magnetic resonance imaging apparatus and the image processing apparatus according to the embodiment will be described in detail with reference to the accompanying drawings.

(Embodiment)
FIG. 1 is a diagram showing a magnetic resonance imaging device 100 according to an embodiment. Subject P (within the frame of the dotted line in FIG. 1) is not included in the magnetic resonance imaging apparatus 100.

The static magnetic field magnet 1 is formed in a hollow cylindrical shape and generates a uniform static magnetic field in the internal space. The static magnetic field magnet 1 is, for example, a permanent magnet, a superconducting magnet, or the like. The gradient magnetic field coil 2 is formed in a hollow cylindrical shape and generates a gradient magnetic field in the internal space.

Specifically, the gradient magnetic field coil 2 is arranged inside the static magnetic field magnet 1 and receives a gradient magnetic field pulse from the gradient magnetic field power supply 3 to generate a gradient magnetic field. The gradient magnetic field power supply 3 supplies the gradient magnetic field pulse to the gradient magnetic field coil 2 according to the control signal transmitted from the sequence control circuit 10.

The bed 4 includes a top plate 4a on which the subject P is placed, and the top plate 4a is inserted into the cavity of the inclined magnetic field coil 2 which is an image pickup port in a state where the subject P is placed. Normally, the sleeper 4 is installed so that the longitudinal direction is parallel to the central axis of the static magnetic field magnet 1.

The sleeper control circuit 5 drives the sleeper 4 to move the top plate 4a in the longitudinal direction and the vertical direction.

The transmission coil 6 generates a magnetic field. Specifically, the transmission coil 6 is arranged inside the gradient magnetic field coil 2, and receives an RF (Radio Frequency) pulse from the transmission circuit 7 to generate a magnetic field. The transmission circuit 7 supplies the RF pulse corresponding to the Larmor frequency to the transmission coil 6 according to the control signal transmitted from the sequence control circuit 10.

The receiving coil 8 receives a magnetic resonance signal (hereinafter, MR (Magnetic Resonance) signal). Specifically, the receiving coil 8 is arranged inside the gradient magnetic field coil 2 and receives the magnetic resonance signal radiated from the subject P due to the influence of the magnetic field. Further, the receiving coil 8 outputs the received magnetic resonance signal to the receiving circuit 9.

The receiving circuit 9 generates magnetic resonance signal data based on the magnetic resonance signal output from the receiving coil 8 according to the control signal sent from the sequence control circuit 10. Specifically, the receiving circuit 9 generates magnetic resonance signal data by digitally converting the magnetic resonance signal output from the receiving coil 8, and images the generated magnetic resonance signal data via the sequence control circuit 10. It is transmitted to the processing device 200. The receiving circuit 9 may be provided on the gantry device side including the static magnetic field magnet 1, the gradient magnetic field coil 2, and the like.

The sequence control circuit 10 (imaging unit) controls the gradient magnetic field power supply 3, the transmission circuit 7, and the reception circuit 9. Specifically, the sequence control circuit 10 transmits a control signal based on the pulse sequence execution data transmitted from the image processing device 200 to the gradient magnetic field power supply 3, the transmission circuit 7, and the reception circuit 9. For example, the sequence control circuit 10 is an integrated circuit such as an ASIC (Application Specific Integrated Circuit) and an FPGA (Field Programmable Gate Array), and an electronic circuit such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).

The image processing device 200 includes a processing circuit 150, a memory 132, an input interface 134, and a display 135. Further, the processing circuit 150 has a control function 150a, a generation function 150b, an estimation function 150c, an interface function (not shown), a reception function, and a determination function. Detailed processing of the control function 150a, the generation function 150b, and the estimation function 150c will be omitted.

Each processing function performed by the control function 150a, the generation function 150b, and the estimation function 150c is stored in the memory 132 in the form of a program that can be executed by a computer. The processing circuit 150 is a processor that realizes a function corresponding to each program by reading a program from the memory 132 and executing the program. In other words, the processing circuit 150 in the state where each program is read has each function shown in the processing circuit 150 of FIG. In FIG. 1, it has been described that the processing functions performed by the control function 150a, the generation function 150b, and the estimation function 150c are realized by a single processing circuit 150, but a plurality of independent processors are combined. The processing circuit 150 may be configured to realize the function by executing a program by each processor.

In other words, each of the above-mentioned functions may be configured as a program, and one processing circuit may execute each program, or a specific function may be implemented in a dedicated and independent program execution circuit. You may. The control function 150a, the generation function 150b, the estimation function 150c, the reception function, and the determination function of the processing circuit 150 are examples of a control unit, a generation unit, an estimation unit, a reception unit (control unit), and a determination unit, respectively. The display 135 is an example of a display unit.

The term "processor" used in the above description refers to, for example, a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), an integrated circuit for a specific application (Application Specific Integrated Circuit: ASIC), a programmable logic device (for example, a simple programmable logic device). A circuit of a programmable logic device (Single Programmable Logical Device: SPLD), a composite programmable logic device (Complex Programmable Logical Device: CPLD), and a field programmable gate array (field programmable gate array (meaning FPGA)). The processor realizes the function by reading and executing the program stored in the memory 132. Instead of storing the program in the memory 132, the program may be directly embedded in the circuit of the processor. In this case, the processor realizes the function by reading and executing the program embedded in the circuit. For example, the memory 132 is a RAM (Random Access Memory), a semiconductor memory element such as a flash memory, a hard disk, an optical disk, or the like.

The memory 132 stores the image data stored by the generation function 150b and other data used in the magnetic resonance imaging apparatus 100. For example, the memory 132 is composed of a semiconductor memory element such as a RAM (Random Access Memory) and a flash memory (Flash Memory), a hard disk, an optical disk, and the like.

The input interface 134 receives various instructions and information inputs from the operator. The input interface 134 is, for example, a pointing device such as a mouse or a trackball, or an input device such as a keyboard.

The display 135 displays various information such as image data under the control of the processing circuit 150. A display 135, for example, a display device such as a liquid crystal display.

The processing circuit 150 is connected to the sequence control circuit 10 by an interface function (not shown), and controls the input / output of data transmitted / received between the sequence control circuit 10 and the image processing device 200.

The processing circuit 150 controls the entire magnetic resonance imaging device 100 by the control function 150a, and controls imaging, image generation, image display, and the like. For example, the control function 150a is an integrated circuit such as an ASIC or FPGA, or an electronic circuit such as a CPU or MPU.

The processing circuit 150 efficiently confirms and corrects the determination of the imaging position of the reference cross section and the information on the image quality at the determined reference cross section position by the control function 150a, as will be described later.

The processing circuit 150 reconstructs image data from the magnetic resonance signal data transmitted from the sequence control circuit 10 by the generation function 150b, and stores the reconstructed image data in the memory 132. Further, the processing circuit 150 acquires the three-dimensional data including the minimum imaging of the subject P and the cross-sectional position being set via the input interface 134 from the memory 132 by the generation function 150b, and corresponds to the MPR (Multi Planar). Generate an image. The generated MPR image is stored in the memory 132.

The processing circuit 150 acquires the three-dimensional data including the subject P, the cross-sectional position being set, and the imaging parameter from the memory 132 via the input interface 134 by the estimation function 150c, and relates to the image quality of the image for diagnosis. Estimate the information. The estimated image quality information is stored in the memory 132.

Subsequently, the background of the embodiment will be briefly described.

As an examination procedure by magnetic resonance imaging, for example, in the case of the heart, a body axis cross-sectional image (Axial) called a scout image (Scout) or a locator image (Locator), a sagittal cross-sectional image (Sagittal), and a sagittal image (Sagittal), and After imaging a coronal section image, a multi-slice image (Axial multi-slice) which is a plurality of body axis cross sections is imaged, and then a reference section is imaged. Here, the reference cross section is a cross-sectional image based on anatomical features, and in the case of the heart, a left ventricular vertical long-axis image and a left ventricular horizontal long-axis image (Left ventricular horizontal long). -axis, Left ventricular short-axis, Left ventricular 2-chamber long-axis, Left ventricular 3-chamber long- axis), left ventricular 4-chamber long-axis, etc. In the inspection, for example, it is necessary to set the cross-sectional position of the reference cross section. The reference cross section and the method of setting the reference cross section are defined not only for the heart but also for various objects such as the brain, shoulders, and knees.

Further, in the inspection, it is necessary to set various imaging parameters in addition to the setting of the cross-sectional position described above. Here, the imaging parameters include, for example, the FOV, the number of phase encodes, the number of slices, the reduction factor of parallel imaging (Parallel Imaging) such as the SENSE (Sensitivity Encoding) method for thinning out sampling and imaging at high speed, and the like. Is.

A method of setting a cross-sectional position or the like based on information regarding a form of a cross-sectional position is known. However, since these technologies do not include information on image quality, for example, inexperienced radiological technologists often have to retake images due to poor image quality as a result of taking images without considering information on image quality in advance. As a result, the inspection throughput may decrease.

Against this background, the magnetic resonance imaging apparatus 100 according to the embodiment estimates information regarding image quality, superimposes the estimated information on image data or a cross-sectional image, and displays the information on a display unit (display 135).

FIG. 2 is a flowchart showing a procedure of processing performed by the magnetic resonance imaging apparatus according to the embodiment. 3 to 10 are diagrams illustrating the processing performed by the magnetic resonance imaging apparatus according to the embodiment.

The sequence control circuit 10 executes the first imaging (step S100). Subsequently, the processing circuit 150 acquires image data (for example, three-dimensional data) based on the first imaging performed by the sequence control circuit 10 in step S100 by an acquisition unit (not shown) (step S110).

Here, an example of such image data is a locator image showing morphological information of the subject P to be imaged. At this time, in step S100, the sequence control circuit 10 executes imaging for acquiring a locator image as the first imaging. Here, as a specific example of the first imaging which is an imaging for acquiring a locator image, for example, a 3D FFE (Fast Field Echo) sequence, which is a GE (Gradient Echo) system pulse sequence, or a 3D SSFP (3D SSFP) Steady-state Free Precession) sequence. Further, the sequence control circuit 10 may add a pulse sequence for applying a T2 preparation pulse prior to the 3D FFE sequence or the 3D SFP sequence. When the sequence control circuit 10 applies the T2 preparation pulse, the processing circuit 150 can generate an image in which the tissue contrast is emphasized by the generation function 150b.

Further, for example, as another example of such image data, an image (sensitivity map) showing the sensitivity distribution of the receiving coil 8 can be mentioned. At this time, in step S100, the sequence control circuit 10 executes imaging for acquiring the sensitivity map as the first imaging. Specifically, the sequence control circuit 10 performs imaging using, for example, a body coil having high spatial uniformity and a receiving coil 8 (multi-coil) having low spatial uniformity.

Subsequently, the processing circuit 150 generates an image related to the body coil from the image taken by using the body coil by the generation function 150b. Further, the processing circuit 150 generates a plurality of images for each element of the receiving coil 8 from the imaging performed by using the receiving coil 8 by the generation function 150b. In step S110, the processing circuit 150 takes an image representing the sensitivity distribution of the receiving coil 8 (sensitivity map) by taking the ratio of the image related to the body coil and the plurality of images generated for each element of the receiving coil 8. To get.

Further, for example, as another example of such image data, a shimming image showing a magnetic field distribution of a static magnetic field (B0) or a high-frequency magnetic field (B1) can be mentioned. That is, in step S100, the sequence control circuit 10 performs imaging for obtaining a shimming image. Subsequently, the processing circuit 150 generates a shimming image based on the imaging performed in step S100 by the generation function 150b. For example, the processing circuit 150 calculates an image representing the distribution of B0, which is the intensity distribution of the static magnetic field, from the phase difference of a plurality of magnetic resonance imaging images having different echo times by the generation function 150b. Further, for example, the processing circuit 150 calculates an image representing the distribution of B1, which is the intensity distribution of the high-frequency magnetic field, from the intensity ratio of a plurality of magnetic resonance imaging images to which different excitation pulses are applied, for example, by the generation function 150b.

Subsequently, the sequence control circuit 10 determines whether or not to end the process (step S120). When it is determined that the inspection sequence to be processed does not remain and the sequence control circuit 10 ends the process (step S120 Yes), the sequence control circuit 10 ends the process. On the other hand, when the inspection sequence to be processed remains, the sequence control circuit 10 determines that the processing is not completed (step S120 No.), and the processing proceeds to step S130.

Subsequently, the processing circuit 150 sets the cross-sectional position of the inspection sequence and the imaging parameter (step S130). Specifically, first, the processing circuit 150 performs information for specifying the cross-sectional position of the inspection sequence and information regarding the imaging parameters (when the second imaging after the first imaging is executed) through the input interface 134. Accepts input of image quality information).

The processing circuit 150 receives input of information for specifying the cross-sectional position of the inspection sequence. Here, the processing circuit 150 uses the input interface 134 as an example of information for specifying the cross-sectional position of the inspection sequence, for example, the position of one point o on the cross section and the two unit vectors u constituting the plane. , V direction input is accepted. When the components of o, u, and v are specifically written, they are represented by the following formulas (1) and (2), for example.

An example of such an input screen is shown in FIG. Image 13 represents a reconstructed image of the inspection sequence that has already been imaged. The cross section 11 represents a cross section of the inspection sequence set by the processing circuit 150 in step S130. The processing circuit 150 receives, for example, inputs in the direction of the center position (point o) of the cross section 11 and the two unit vectors u and v constituting the cross section 11.

Further, the processing circuit 150 accepts input of information regarding imaging parameters. FIG. 4 shows such a situation. The edit box 21 is an edit box for setting the matrix size. The check box 22 is a check box for setting whether or not to use each element of the receiving coil 8. The edit box 23 is an edit box for setting the shooting range.

The processing circuit 150 inputs, for example, information regarding the matrix size in the read direction (RO (Readout) direction), the matrix size in the phase encoding direction (PE (Phase Endode) direction), and the matrix size in the slice (Slice) direction. Accept through 21.

The processing circuit 150 receives, for example, whether or not the receiving coil 8 is used for each element through the edit box 22.

The processing circuit 150 receives, for example, input of information regarding an imaging range in the reading direction (RO direction) and, for example, a phase encoding direction (PE direction) through the edit box 23.

The processing circuit 150 receives, for example, the acceleration rate and slice thickness in the PE direction of parallel imaging through the edit box 24 and the like.

The processing circuit 150 sets the cross-sectional position and the imaging parameter of the inspection sequence based on the received information. The processing circuit 150 stores the set cross-sectional position and imaging parameter of the inspection sequence in the memory 132.

Further, the processing circuit 150 may treat parameters such as the current value flowing through the static magnetic field correction coil and the waveform, phase, and intensity of each transmission port for high-frequency magnetic field adjustment as imaging parameters.

Returning to FIG. 2, the processing circuit 150 generates an MPR image (cross-sectional image) including a predetermined region of interest in a predetermined cross section from the image data (for example, three-dimensional data) acquired in step S110 (step S140). Subsequently, the processing circuit 150 causes the control function 150a to display the cross-sectional image (MPR image) generated in step S140 on the display 135 (step S150).

FIG. 5 shows an example of such an MPR image. The cross-sectional image area 41 represents an area in which an MPR image corresponding to the cross-sectional position being set is generated. On the other hand, the imaging range 40 represents the imaging range being set. In step S140, the processing circuit 150 generates a cross-sectional image at a cross-sectional image region 41 that is wider than the imaging range 40, which is the imaging range being set, and is the same as the cross-sectional position being set.

In this way, for example, the processing circuit 150 generates a cross-sectional image in a cross-sectional image region 41 wider than the imaging range 40, which is the imaging range being set, so that, for example, the imaging range being set from outside the imaging range being set. Makes it easier for the user to predict the size of incoming artifacts.

Subsequently, the processing circuit 150 uses the estimation function 150c to estimate information on the image quality when imaging is performed based on the cross-sectional image generated in step S140 and the parameters related to the setting of imaging by magnetic resonance imaging (). Step S160). That is, the processing circuit 150 obtains information on the image quality when the second imaging that is later than the first imaging is executed, the imaging conditions set for the second imaging, and the magnetic resonance image related to the first imaging. Estimate based on. Subsequently, the processing circuit 150 superimposes the information on the image quality estimated by the estimation function 150c in step S160 on the above-mentioned image data or the cross-sectional image by the control function 150a and displays it on the display 135 (step S170). That is, the processing circuit 150 superimposes the estimation result on the magnetic resonance image related to the first imaging by the control function 150a and displays it on the display 135.

Here, in step S170, the estimation result is superimposed on the magnetic resonance image because the information on the image quality is superimposed and displayed on the morphological image, the functional image, and the like, so that, for example, the information on the image quality is relative to the position of the tumor. This is because the positional relationship becomes more intuitive and easy to understand.

FIG. 6 shows an example of such a case. The cross-sectional image area 41 represents an area of the MPR image corresponding to the cross-sectional position being set. On the other hand, the imaging range 40 represents the imaging range being set. The fold-back areas 42a and 42b represent fold-back artifacts from outside the imaging range 40. Further, the arrow D indicates the direction of the phase encoding being set.

In step S160, the processing circuit 150 is based on the cross-sectional image generated in step S140 by the estimation function 150c and the imaging range 40 (imaging range 40 when the second imaging is performed) of the imaging by magnetic resonance imaging. Therefore, information on the folded regions 42a and 42b from outside the imaging range, which is information on the image quality when imaging (second imaging) is performed, is estimated. Subsequently, the processing circuit 150 superimposes the information on the image quality estimated by the estimation function 150c in step S160 on the image data or the cross-sectional image and displays it on the display 135 by the control function 150a.

Further, the processing circuit 150 displays the phase encoding direction D being set with an arrow, and estimates a return artifact from outside the assumed imaging range. The processing circuit 150 causes the control function 150a to highlight the estimated folding artifacts on the display 135, for example.

By performing such processing, the user can more easily and intuitively predict the presence or absence of the wrapping artifact. As a result, the user can adjust the imaging conditions so that the folding artifact does not occur. For example, the user can adjust the imaging conditions by expanding the imaging range 40, changing the direction of the phase encoding direction D, applying a saturation pulse, and the like. The user can intuitively adjust the imaging conditions with a small amount of movement of the viewpoint. This point is advantageous, for example, in the case where it is difficult to fix the subject P to the bed 4 in a fixed position at all times, and imaging of parts such as elbows and knees.

In FIG. 6, the case where the cross-sectional image on which the information on the image quality estimated by the estimation function 150c in step S160 is superimposed is the MPR image has been described, but the embodiment is not limited to this. For example, the cross-sectional image on which the information on the estimated image quality is superimposed may be an image for one slice collected in the multi-slice imaging. Further, the cross-sectional image on which the information on the estimated image quality is superimposed may be, for example, projected image data obtained by projecting the three-dimensional volume data by the MIP (Maximum Industry Projection) method. Further, in FIG. 6, the case where the information on the image quality estimated by the estimation function 150c in step S160 is superimposed on the cross-sectional image has been described, but the embodiment is not limited to this. For example, the information regarding the estimated image quality may be superimposed on the image data which is the original data before cutting out the cross section, for example, instead of the cross section image such as MPR.

FIG. 7 shows an example of processing in a case different from that of FIG. The cross-sectional image area 41 represents an area of the MPR image corresponding to the cross-sectional position being set. On the other hand, the imaging range 40 represents the imaging range being set. The fold-back region 42 represents a fold-back artifact from outside the imaging range 40. Further, the arrow D indicates the direction of the phase encoding being set. The image quality information 50 is information regarding the magnetic field strength in the cross-sectional image region 41 (or the imaging range 40).

In the example of FIG. 7, in step S160, the processing circuit 150 relates to the magnetic field strength in the photographing range based on the cross-sectional image generated in step S140 by the estimation function 150c and the shimming adjustment value of the static magnetic field or the high frequency magnetic field. Estimate the information. That is, the processing circuit 150 uses the estimation function 150c to estimate, for example, information on the non-uniformity distribution of the static magnetic field as information on the image quality when the second imaging is executed. Subsequently, the processing circuit 150 superimposes the information on the magnetic field strength in the photographing range estimated by the estimation function 150c in step S160 on the image data or the cross-sectional image and displays it on the display 135 by the control function 150a. That is, the processing circuit 150 superimposes information on the distribution of the non-uniformity of the static magnetic field estimated in step S160 on the magnetic resonance image related to the first imaging by the control function 150a and displays it on the display 135. For example, the processing circuit 150 superimposes a contour map of the static magnetic field on the magnetic resonance image related to the first imaging and the region including the region of interest in the second imaging on the display 135 by the control function 150a. Let me. As another example, when the value of the static magnetic field has an outlier value that is different from the normal value, the processing circuit 150 uses the control function 150a to display the magnetic resonance image of the static magnetic field on the magnetic resonance image according to the first imaging. Information about the position where the value is an outlier is superimposed and displayed on the display 135.

By performing such processing, when the information regarding the magnetic field strength in the imaging range is, for example, the MPR image of the B0 or B1 map, the MPR image of the B0 or B1 map is superimposed on the cross-sectional image generated in step S140. By displaying the images in a hurry, it becomes possible to easily grasp whether or not the static magnetic field and the high-frequency magnetic field are sufficiently uniform at the point of interest.

As another example, in step S160, the processing circuit 150 estimates information about the g-factor by the estimation function 150c based on the cross-sectional image generated in step S140 and the acceleration rate of parallel imaging. May be good. Subsequently, the processing circuit 150 superimposes the information on the g-factor estimated by the estimation function 150c in step S160 on the image data or the cross-sectional image and displays it on the display 135 by the control function 150a.

In this way, the processing circuit 150 calculates the g-factor based on the sensitivity map, the imaging range, and the acceleration rate of the parallel imaging by the estimation function 150c, and superimposes it on the cross-sectional image by the control function 150a, for example, on the display 135. To display. This makes it easy to determine whether or not the point of interest is at a position where folding artifacts are likely to occur.

As another example, in step S160, the processing circuit 150 uses the estimation function 150c to capture the cross-sectional image generated in step S140 and the imaging range of the imaging by magnetic resonance imaging (imaging when the second imaging is performed). Information about the distribution of the sensitivity of the receiving coil may be estimated based on the range).

In this case, the processing circuit 150 subsequently superimposes the information on the sensitivity distribution of the receiving coil estimated by the estimation function 150c in step S160 on the cross-sectional image and displays it on the display 135 by the control function 150a. This makes it possible to grasp how much the coil sensitivity is at each position on the imaging cross section.

As another example, in step S160, the processing circuit 150 uses the estimation function 150c to start from the magnetic field center based on the cross-sectional image generated in step S140 and the information of the imaging range of each element of the receiving coil 8. Information about the distance may be estimated. In this case, the processing circuit 150 subsequently superimposes the information estimated by the estimation function 150c in step S160 on the cross-sectional image, for example, by the control function 150a and displays it on the display 135.

This allows, for example, the user to see how far the cross-sectional position being set is from the center of the magnetic field.

FIG. 8 shows an example of processing in a case different from that of FIGS. 6 and 7. The cross-sectional image area 41 represents an area of the MPR image corresponding to the cross-sectional position being set. On the other hand, the imaging range 40 represents the imaging range being set. The folding area 51 and the folding area 52 represent the area where the folding artifact occurs.

In the example of FIG. 8, in step S160, the processing circuit 150 estimates the information about the folded image before unfolding based on the cross-sectional image generated in step S140 and the acceleration rate of parallel imaging by the estimation function 150c. do. Subsequently, the processing circuit 150 superimposes the information estimated by the estimation function 150c in step S160 on the cross-sectional image and displays it on the display 135 by the control function 150a.

As described above, the processing circuit 150 causes the display 135 to display the folded image before unfolding of the parallel imaging estimated from the imaging range and the acceleration rate of the parallel imaging by the control function 150a. This allows the user to see if the point of interest is at a position where fold-back artifacts are likely to occur.

FIG. 9 shows an example of processing different from that of FIGS. 6 to 8. The cross-sectional image area 41 represents an image area corresponding to the cross-sectional position being set. On the other hand, the imaging range 40 represents the imaging range being set. The numbers 53a, 53b, 53c and 53d represent the numbers of the coil elements displayed on the MPR image (cross-sectional image). For example, the number 53a means that the number of the coil element in the vicinity of the corresponding place is "3". Further, for example, the number 53b means that the number of the coil element in the vicinity of the corresponding place is "4".

In the example of FIG. 9, in step S160, the processing circuit 150 estimates information about the position of the receiving coil used in imaging by the estimation function 150c. Subsequently, in step S170, the processing circuit 150 superimposes the information estimated by the estimation function 150c in step S160 on the cross-sectional image and displays it on the display 135 by the control function 150a.

As described above, the processing circuit 150 causes the control function 150a to display the coil element number of the receiving coil 8 on the MPR image (cross-sectional image). As a result, the user can confirm the arrangement of the coil elements on the setting screen position. As a result, the user can easily determine whether the coil element is selected correctly.

In step S170, the processing circuit 150 uses the control function 150a to obtain information estimated by the estimation function 150c in step S160, and information on whether the coil element is in the back or in front with respect to the cross-sectional position is a numerical value or a shape. In addition to the information represented by, the image data or the cross-sectional image may be superimposed and displayed on the display 135.

Further, the processing circuit 150 may accept the input of the selection and non-selection of the coil element of the input interface 134, and execute the estimation function 150c based on the received input. In such a case, in step S160, the processing circuit 150 is used in imaging (second imaging) based on the cross-sectional image and information on whether or not to use each element of the receiving coil 8 by the estimation function 150c. Information about the position of the receiving coil 8 is estimated. Subsequently, in step S170, the processing circuit 150 superimposes the information estimated by the estimation function 150c in step S160 on the image data or the cross-sectional image and displays it on the display 135 by the control function 150a.

FIG. 10 shows an example of processing in a case different from FIGS. 6 to 9. The cross-sectional image area 41 represents an area of the MPR image (cross-sectional image) corresponding to the cross-sectional position being set. On the other hand, the imaging range 40 represents the imaging range being set. The magnetostrictive correction image 54 refers to an image of magnetostriction correction displayed on the MPR image (cross-sectional image). Here, the magnetic field distortion correction means that the image is distorted when the gradient magnetic field at the time of encoding such as the reading direction does not become an ideal straight line due to design restrictions or the like (for example, a perfect circular object is imaged as an ellipse). ) The phenomenon is corrected by post-processing such as image deformation.

In the example of FIG. 10, in step S160, the processing circuit 150 corrects the magnetic field distortion based on the cross-sectional image generated in step S140 by the estimation function 150c and the information of the imaging range for each element of the receiving coil. Estimate the image. Subsequently, in step S170, the processing circuit 150 superimposes the information estimated by the estimation function 150c in step S160 on the image data or the cross-sectional image and displays it on the display 135 by the control function 150a.

As described above, the processing circuit 150 displays the imaging range and the image after magnetostriction correction on the display 135 by the control function 150a. In particular, when the subject P is set in a place far from the center of the magnetic field such as the shoulder, elbow, and hand, the correction amount of the magnetic field distortion correction becomes large, and the user's assumption when the imaging position is set and after the magnetic field distortion correction are performed. It is easy to happen that the position of the image is different. Even in such a case, the user can confirm the change of the image before and after the magnetic field distortion correction in advance.

There are various possibilities for the timing of step S170, that is, the timing at which the processing circuit 150 superimposes the information on the image quality on the cross-sectional image and displays it on the display 135 by the control function 150a.

As an example of such a possibility, for example, the processing circuit 150 receives a correction input of a parameter related to an imaging setting by magnetic resonance imaging from a user by a reception function (not shown). While the processing circuit 150 receives the correction input by the reception function, the processing circuit 150 superimposes the information on the image quality on the cross-sectional image and displays it on the display 135 by the control function 150a. On the other hand, while the reception function does not accept the correction input, the processing circuit 150 hides the information related to the image quality by the control function 150a.

Further, as another example of such a possibility, for example, the processing circuit 150 receives a correction input of a parameter related to an imaging setting by magnetic resonance imaging from a user by a reception function (not shown). After the acceptance of the correction input is completed, the processing circuit 150 superimposes the information on the image quality on the cross-sectional image and displays it on the display 135 by the control function 150a. Further, the processing circuit 150 may automatically hide the information on the image quality by the control function 150a, for example, when a predetermined button is pressed or after a certain period of time has elapsed from the completion of the correction input.

Further, as another example of such a possibility, for example, the processing circuit 150 makes a determination by comparing a value representing information on image quality with a predetermined threshold value by a determination function (not shown). The processing circuit 150 superimposes information on image quality on the cross-sectional image and displays it on the display 135 based on the determination result by the determination function by the control function 150a. For example, the processing circuit 150 automatically displays the cross-sectional image and the image quality information when the estimated image quality information exceeds a predetermined threshold value.

Returning to the flowchart of FIG. 2, the processing circuit 150 receives the input of the parameter correction from the user who sees the information on the image quality superimposed on the cross-sectional image on the display 135 in step S170 through the input interface 134 (step). S180). That is, the processing circuit 150 receives the designated operation for the first magnetic resonance image from the operator through the input interface 134 by the reception function. When the input of the parameter modification is accepted (step S180 Yes), the process returns to step S130. That is, the processing circuit 150 changes the setting of the imaging condition regarding the second imaging based on the designated operation. If the parameter is not modified (step S180 No), the process proceeds to step S190.

That is, the processing circuit 150 receives, for example, the designation of the region of interest for shimming from the operator in step S180 by the reception function. For example, the processing circuit 150 receives from the operator, for example, the designation of the region of interest in imaging by the reception function. In such a case, when focusing on the heart, for example, the operator specifies the region of interest by selecting the region around the heart on the screen. Further, as another example, the processing circuit 150 receives from the operator the designation of the area to be excluded from the calculation processing in, for example, the shimming by the reception function. That is, for example, in step S170, when the contour map of the static magnetic field is superimposed on the magnetic resonance image and displayed on the display 135, the operator reads the deviation value from the contour map displayed on the display 135. Based on the reading result, specify the area to be excluded from the calculation processing in shimming. This makes it possible to reduce image artifacts by excluding the selected area from the calculation process.

Subsequently, the processing circuit 150 calculates the value for shimming based on the designation of the region of interest by the control function 150a, and changes the setting of the imaging condition of the second imaging so as to apply the calculated value. do. For example, in the above step, when the operator specifies a region to be excluded from the calculation processing in shimming, the processing circuit 150 uses the control function 150a to set the value of the static magnetic field around the designated region. The value in the region of is replaced with the interpolated value, and the setting of the imaging condition for the second imaging is changed based on the replaced value.

The processing circuit 150 may automatically correct the imaging parameters based on the MPR image generated in step S140 and the image information estimated in step S160. As an example, for example, the processing circuit 150 has information such as the current value flowing through the static magnetic field correction coil and the strength, waveform, and phase of the multi-transmission coil based on the values of the B0 distribution and the B1 distribution at the cross-sectional position being set. May be adjusted (simming). Further, for example, the processing circuit 150 may calculate the center of gravity of the region other than air of the image after the magnetic field distortion, and correct the imaging position so that the object comes to the center of the imaging range after the magnetic field distortion. Further, the processing circuit 150 specifies, for example, a region of interest on the cross-sectional image through the input interface 134, and the imaging range, encoding direction, etc. You may perform shimming and correction of the imaging position.

Finally, the sequence control circuit 10 executes a second imaging, which is a diagnostic imaging (imaging of the inspection sequence), based on the determined cross-sectional position and imaging parameters (step S190). The second imaging is, for example, an imaging after the first imaging. After the end of step S190, the process returns to step S120.

It should be noted that the above-mentioned image quality information has different valid information depending on the inspection site and the inspection sequence. For example, in the case of contrast-enhanced dynamic examination of the breast, the information of the B0 and B1 maps, which have a high correlation with the fat suppression performance, is effective. In addition, for example, since the setting position of the shoulder, elbow, hand, etc. often changes depending on the state of the subject P, the information of the folding outside the FOV, the sensitivity distribution image of the receiving coil, and the image before and after the magnetic field distortion is effective. be. Further, in a general magnetic resonance imaging inspection, the memory 132 holds a memory 132 in which the imaging parameters for each sequence grouped according to the inspection site and the inspection content are adjusted in advance. Subsequently, the sequence control circuit 10 selects the imaging sequence group held according to the examination content, sets the cross-sectional position and fine-tunes the imaging parameters according to the patient's situation, and starts the examination. From such a background, the memory 132 may set whether or not to display the cross-sectional image and the image quality information and the type of the image quality information to be displayed for each imaging sequence held in advance.

The embodiment is not limited to this.

In the example of the case where the processing circuit 150 generates the locator image, in the embodiment, the case where the locator image is three-dimensional data has been described as an example. However, for example, in step S100, the sequence control circuit 10 may perform multi-slice imaging using, for example, a 2D sequence. In such a case, in step S110, the processing circuit 150 generates a locator image based on the multi-slice imaging performed by the sequence control circuit 10 in step S100.

In an example where the three-dimensional data in step S110 is a sensitivity map, for example, in step S110, the processing circuit 150 uses the ratio of the image of each element of the coil 8 to the SOS (Sum of Squares) of all element images. You may generate a sensitivity map.

In the example where the three-dimensional data in step S110 is a shimming image, in step S110, the processing circuit 150 may calculate the B0 distribution from the MRS (Magnetic Resolution Spectroscopy) image.

In an example of generating the three-dimensional data of step S110 as a shimming image, in step S110, the processing circuit 150 may calculate the B1 distribution based on the deviation of a plurality of tagging images.

Further, for example, the three-dimensional data acquired in step S110 may have a plurality of roles. For example, the three-dimensional data acquired in step S110 may have both a role as image data representing a sensitivity map and a role as a locator image showing morphological information. Further, for example, the three-dimensional data acquired in step S110 may have both a role as image data representing a shimming map and a role as a locator image showing morphological information.

In step S130, the processing circuit 150 may specify, for example, three points on the cross section as an example of information that identifies the location of the cross section of the inspection sequence through the input device 134.

As an input interface for the cross-sectional position of the inspection sequence in step S130, when the reconstructed image of the inspection sequence that has already been imaged and the set cross section are not orthogonal to each other, the processing circuit 150 makes the FOV a parallelogram by the control function 150a. By doing so, the positional relationship between the reconstructed image and the set cross section may be displayed on the display 135.

In step S130, the processing circuit 150 may display a plurality of reconstructed images on the display 135 and accept input of information regarding the set cross section.

The data formats of the three-dimensional data and the image quality information in the embodiment are not limited to the above examples. For example, for the B0 / B1 map and the distance image from the center of the magnetic field, an arbitrary threshold value may be set as a dangerous water area reference and may be a binary image of an OK area or an NG area. Further, the data format may be configured by numerically displaying whether or not the NG region exists in the first place and how much the volume NG region exists.

In step S170, the processing circuit 150 superimposes the estimation result on the magnetic resonance image and displays it on the display 135 because the information on the image quality is superimposed on the morphological image, the functional image, and the like. It has been explained that the relative positional relationship of the information with respect to the position of the tumor is more intuitive and easy to understand, but the embodiment is not limited to this. That is, the processing circuit 150 may independently display the estimation result on the display 135. In such a case, the magnetic resonance imaging device 100 according to the embodiment includes a sequence control circuit 120 and a processing circuit 150. The sequence control circuit 120 executes a first imaging and a second imaging after the first imaging on the subject. The processing circuit 150 estimates information on the image quality when the second imaging is performed based on the magnetic resonance image related to the first imaging and the imaging conditions set for the second imaging. The processing circuit 150 displays the estimated result on the display 135. The processing circuit 150 receives a designated operation for the magnetic resonance image from the operator. The processing circuit 150 changes the setting of the imaging condition regarding the second imaging based on the designated operation.

(program)
The instructions given in the processing procedure shown in the above-described embodiment can be executed based on a program that is software. A general-purpose computer system stores this program in advance, and by reading this program, it is possible to obtain an effect similar to the effect of the magnetic resonance imaging apparatus or image processing apparatus of the above-described embodiment. The instructions described in the above-described embodiments can be executed by a computer as a program such as a magnetic disk (flexible disk, hard disk, etc.) or an optical disk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD). ± R, DVD ± RW, etc.), semiconductor memory, or similar recording medium. The storage format may be any form as long as it is a storage medium that can be read by a computer or an embedded system. If the computer reads the program from this recording medium and causes the CPU to execute the instructions described in the program based on this program, the same operation as the magnetic resonance imaging device and the image processing device of the above-described embodiment can be realized. can do. Of course, when the computer acquires or reads the program, it may be acquired or read through the network.

Further, the OS (operating system) running on the computer based on the instruction of the program installed on the computer or the embedded system from the storage medium, the database management software, the MW (middleware) such as the network, and the like are the above-described embodiments. You may execute a part of each process to realize.

Further, the storage medium is not limited to a medium independent of a computer or an embedded system, but also includes a storage medium in which a program transmitted by a LAN (Local Area Network), the Internet, or the like is downloaded and stored or temporarily stored.

Further, the storage medium is not limited to one, and when the processing in the above-described embodiment is executed from a plurality of media, the storage medium in the embodiment is included, and the configuration of the medium may be any configuration. ..

The computer or embedded system in the embodiment is for executing each process in the above-described embodiment based on the program stored in the storage medium, and is a device including one such as a personal computer and a microcomputer, and a plurality of devices. The device may have any configuration such as a system connected to a network.

Further, the computer in the embodiment is not limited to a personal computer, but also includes an arithmetic processing unit, a microcomputer, etc. included in an information processing device, and is a general term for devices and devices capable of realizing the functions in the embodiment by a program. ..

(Hardware configuration)
FIG. 11 is a diagram showing a hardware configuration of the image processing device 200 according to the embodiment. The image processing device 200 according to the above-described embodiment is connected to a network with a control device such as a CPU (Central Processing Unit) 310 and a storage device such as a ROM (Read Only Memory) 320 or a RAM (Random Access Memory) 330. It is provided with a communication interface 340 for communicating with the user and a bus 301 for connecting each unit. The program executed by the image processing apparatus 200 according to the above-described embodiment is provided by being incorporated in a ROM 320 or the like in advance. Further, the program executed by the image processing device 200 according to the above-described embodiment can make the computer function as each part of the above-mentioned image processing device 200. This computer can read a program from a computer-readable storage medium onto the main storage device and execute the program by the CPU 310.

Although the magnetic resonance imaging device 100 has been described in the embodiment, the embodiment can be similarly applied to the image processing device 200. For example, the image processing apparatus 200 according to the embodiment includes a processing circuit 150. The processing circuit 150 uses the estimation function 150c to set information regarding the image quality when the second imaging after the first imaging is performed with respect to the magnetic resonance image related to the first imaging and the second imaging. Estimate based on the imaging conditions. The processing circuit 150 superimposes the estimated result on the magnetic resonance image and displays it on the display 135 by the control function 150a, receives a designated operation for the magnetic resonance image from the operator, and based on the designated operation, the second Change the setting of imaging conditions related to imaging.

According to the magnetic resonance imaging apparatus and the image processing apparatus of at least one embodiment described above, information on image quality can be confirmed.

Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

150 Processing circuit 150a Control function 150b Generation function 150c Estimation function

Claims (9)

An imaging unit that executes a first imaging and a second imaging after the first imaging of a subject, and an imaging unit.
An estimation unit that estimates information on image quality when the second imaging is performed based on the magnetic resonance image related to the first imaging and the imaging conditions set for the second imaging.
The estimation result is superimposed on the magnetic resonance image and displayed on the display unit, the designated operation for the magnetic resonance image is accepted from the operator, and the setting of the imaging condition for the second imaging is changed based on the designated operation. Equipped with a control unit
The estimation unit estimates information on the non-uniformity distribution of the static magnetic field as information on the image quality.
The control unit superimposes information on the estimated non-uniformity distribution of the static magnetic field on the magnetic resonance image and displays it on the display unit, and specifies a region to be excluded from the calculation process in shimming. receiving from the operator, based on the specified area to be the target out to calculate a value for shimming, to apply the calculated value, to change the settings of the imaging conditions of the second imaging, magnetic Resonance imaging device. Further provided with a generation unit that generates a cross-sectional image including a predetermined region of interest in a predetermined cross section from the image data.
The estimation unit estimates the information based on the cross-sectional image and the imaging conditions.
The magnetic resonance imaging apparatus according to claim 1, wherein the control unit superimposes the information on the image data or the cross-sectional image and displays the information on the display unit. The magnetic resonance according to claim 2 , wherein the image data is any one of a locator image showing morphological information of an imaging target, an image showing the sensitivity distribution of the receiving coil, and a shimming image showing the magnetic field distribution of a static magnetic field or a high-frequency magnetic field. Imaging device. The control unit receives the correction input of the information from the user, and while receiving the correction input, superimposes the information on the cross-sectional image and displays it on the display unit, and while the correction input is not received. The magnetic resonance imaging apparatus according to claim 2 or 3, which hides the information. The second or third aspect of claim 2 or 3, wherein the control unit receives a correction input of the information from the user, and after the reception of the correction input is completed, superimposes the information on the cross-sectional image and displays it on the display unit. Magnetic resonance imaging device. Wherein the control unit performs a determination by comparing the value with a predetermined threshold representing the said information, the determination based on the result, and displays the information on the display unit is superimposed on the cross-sectional image, claim 2 or 3 The magnetic resonance imaging apparatus according to. The estimation unit obtains information on the image quality when the second imaging is performed, based on the magnetic resonance image related to the first imaging and the imaging conditions set for the second imaging. The magnetic resonance imaging apparatus according to claim 1. An imaging unit that executes a first imaging and a second imaging after the first imaging of a subject, and an imaging unit.
An estimation unit that estimates information on image quality when the second imaging is performed based on the magnetic resonance image related to the first imaging and the imaging conditions set for the second imaging.
A control unit that displays the result estimated by the estimation unit on a display, accepts a designation operation for the magnetic resonance image from an operator, and changes the setting of imaging conditions related to the second imaging based on the designation operation. Prepare ,
The estimation unit estimates information on the non-uniformity distribution of the static magnetic field as information on the image quality.
The control unit receives the designation of the area to be excluded from the calculation process in the shimming from the operator, calculates the value for shimming based on the designation of the area to be excluded from the target, and applies the calculated value. as such, to change the settings of the imaging conditions of the second imaging, magnetic resonance imaging device. Information on the image quality when the second imaging after the first imaging is executed is estimated based on the magnetic resonance image related to the first imaging and the imaging conditions set for the second imaging. And the estimation part to do
The estimated result is superimposed on the magnetic resonance image and displayed on the display, and the designated operation for the magnetic resonance image is accepted from the operator.
A control unit that changes the setting of the imaging condition related to the second imaging based on the designated operation is provided .
The estimation unit estimates information on the non-uniformity distribution of the static magnetic field as information on the image quality.
The control unit receives the designation of the area to be excluded from the calculation process in the shimming from the operator, calculates the value for shimming based on the designation of the area to be excluded from the target, and applies the calculated value. as such, to change the settings of the imaging conditions of the second imaging, the image processing apparatus.

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