JP2015054098A - Magnetic resonance imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic resonance imaging apparatus which can collect image data reduced in artifact with better contrast in at least a region of interest.SOLUTION: The magnetic resonance imaging apparatus includes imaging means and image processing means. The imaging means collects image data of a plurality of frames at the same slice position of a subject corresponding to magnetic resonance signals collected in echo times different from each other, by magnetic resonance imaging. The image processing means generates display image data by image processing including processing for adding pixel values in a specific region of other image data of at least one frame to image data of one frame selected from the image data of the plurality of frames.

Description

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

  The MRI apparatus magnetically excites a nuclear spin of a subject placed in a static magnetic field with a radio frequency (RF) signal of Larmor frequency, and generates nuclear magnetic resonance (NMR) generated by this excitation. This is an image diagnostic apparatus that reconstructs an image from a resonance signal.

  As one of imaging methods using an MRI apparatus, a method of collecting T2 star (T2 *) weighted images by a field echo (FE) method is known. In the T2 * weighted image, the local non-uniformity of the magnetic field is sharply reflected in the contrast. For this reason, it is widely used as an imaging method for observing a difference in magnetic susceptibility in a region of interest (ROI).

  The T2 * weighted image is captured by setting a relatively long echo time (TE) in the FE sequence. For this reason, there is a problem that the signal to noise ratio (SNR) of the image is lowered. Therefore, it is conceivable to reduce the reception bandwidth in order to improve the SNR, but there is a possibility that artifacts due to chemical shift and magnetic susceptibility accompanying the increase of TE may appear.

  In view of this, a method has been devised for improving the SNR by a maximum intensity projection (MIP) process of an image collected by an FE multi-echo sequence in which a wide receiving bandwidth is set and different TEs are set. In this method, a plurality of image data is collected while changing TE, and MIP processing of image data corresponding to different TE is executed. As a result, it is possible to compensate for the SNR that is reduced by increasing the reception bandwidth.

JP 2011-229638 A

  However, when MIP processing is performed on a plurality of image data collected by the multi-echo sequence, high-intensity noise and artifacts are generated in the projection image data. For this reason, the image quality of a diagnostic image deteriorates.

  Therefore, an object of the present invention is to provide a magnetic resonance imaging apparatus capable of collecting image data with better contrast and reduced artifacts at least in a region of interest (ROI).

  A magnetic resonance imaging apparatus according to an embodiment of the present invention includes an imaging unit and an image processing unit. The imaging means collects image data of a plurality of frames at the same slice position of the subject by magnetic resonance imaging in correspondence with magnetic resonance signals collected at different echo times. The image processing means is for display by image processing including processing of adding pixel values in a specific region of at least one other frame of image data to one frame of image data selected from the plurality of frames of image data. Generate image data.

1 is a configuration diagram of a magnetic resonance imaging apparatus according to an embodiment of the present invention. The functional block diagram of the computer shown in FIG. The figure which shows an example of the FE sequence which performs multi-echo data collection by different TE. The flowchart which shows the flow of the imaging by the magnetic resonance imaging apparatus shown in FIG.

  A magnetic resonance imaging apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram of a magnetic resonance imaging apparatus according to an embodiment of the present invention.

  The magnetic resonance imaging apparatus 20 includes a cylindrical static magnetic field magnet 21 that forms a static magnetic field, a shim coil 22, a gradient magnetic field coil 23, and an RF coil 24 provided inside the static magnetic field magnet 21.

  In addition, the magnetic resonance imaging apparatus 20 includes a control system 25. The control system 25 includes a static magnetic field power supply 26, a gradient magnetic field power supply 27, a shim coil power supply 28, a transmitter 29, a receiver 30, a sequence controller 31, and a computer 32. The gradient magnetic field power source 27 of the control system 25 includes an X-axis gradient magnetic field power source 27x, a Y-axis gradient magnetic field power source 27y, and a Z-axis gradient magnetic field power source 27z. In addition, the computer 32 includes an input device 33, a display device 34, an arithmetic device 35, and a storage device 36.

  The static magnetic field magnet 21 is connected to a static magnetic field power supply 26 and has a function of forming a static magnetic field in the imaging region by a current supplied from the static magnetic field power supply 26. In many cases, the static magnetic field magnet 21 is composed of a superconducting coil, and is connected to the static magnetic field power supply 26 at the time of excitation and supplied with current. It is common. In some cases, the static magnetic field magnet 21 is composed of a permanent magnet and the static magnetic field power supply 26 is not provided.

  A cylindrical shim coil 22 is coaxially provided inside the static magnetic field magnet 21. The shim coil 22 is connected to the shim coil power supply 28, and is configured such that a current is supplied from the shim coil power supply 28 to the shim coil 22 to make the static magnetic field uniform.

  The gradient magnetic field coil 23 includes an X-axis gradient magnetic field coil 23 x, a Y-axis gradient magnetic field coil 23 y, and a Z-axis gradient magnetic field coil 23 z, and is formed in a cylindrical shape inside the static magnetic field magnet 21. A bed 37 is provided inside the gradient magnetic field coil 23 as an imaging region, and the subject P is set on the bed 37. The RF coil 24 includes a whole body coil (WBC) for transmitting and receiving an RF signal built in the gantry, a bed 37 and a local coil for receiving an RF signal provided near the subject P.

  The gradient magnetic field coil 23 is connected to a gradient magnetic field power supply 27. The X-axis gradient magnetic field coil 23x, the Y-axis gradient magnetic field coil 23y, and the Z-axis gradient magnetic field coil 23z of the gradient magnetic field coil 23 are respectively an X-axis gradient magnetic field power supply 27x, a Y-axis gradient magnetic field power supply 27y, and a Z-axis gradient magnetic field coil 27z. It is connected to the magnetic field power supply 27z.

  The X-axis gradient magnetic field power source 27x, the Y-axis gradient magnetic field power source 27y, and the Z-axis gradient magnetic field power source 27z are supplied with currents supplied to the X-axis gradient magnetic field coil 23x, the Y-axis gradient magnetic field coil 23y, and the Z-axis gradient magnetic field coil 23z, respectively. In the imaging region, a gradient magnetic field Gx in the X-axis direction, a gradient magnetic field Gy in the Y-axis direction, and a gradient magnetic field Gz in the Z-axis direction can be formed, respectively.

  The RF coil 24 is connected to at least one of the transmitter 29 and the receiver 30. The transmission RF coil 24 has a function of receiving an RF signal from the transmitter 29 and transmitting it to the subject P, and the reception RF coil 24 is accompanied by excitation of the nuclear spin inside the subject P by the RF signal. It has a function of receiving the NMR signal generated in this way and giving it to the receiver 30.

  On the other hand, the sequence controller 31 of the control system 25 is connected to the gradient magnetic field power supply 27, the transmitter 29 and the receiver 30. The sequence controller 31 is control information necessary for driving the gradient magnetic field power supply 27, the transmitter 29, and the receiver 30, for example, operation control information such as the intensity, application time, and application timing of the pulse current to be applied to the gradient magnetic field power supply 27. And the gradient magnetic field power supply 27, the transmitter 29 and the receiver 30 are driven according to the stored predetermined sequence to drive the X-axis gradient magnetic field Gx, the Y-axis gradient magnetic field Gy, and the Z-axis gradient magnetic field. It has the function of generating Gz and RF signals.

  The sequence controller 31 is configured to receive raw data, which is complex data obtained by detection of an NMR signal and A / D (analog to digital) conversion in the receiver 30, and supply the received raw data to the computer 32. The

  For this reason, the transmitter 29 is provided with a function of applying an RF signal to the RF coil 24 based on the control information received from the sequence controller 31, while the receiver 30 detects the NMR signal received from the RF coil 24. Then, by executing necessary signal processing and A / D conversion, a function of generating raw data that is digitized complex data and a function of supplying the generated raw data to the sequence controller 31 are provided.

  Further, the computer 32 is provided with various functions by executing the program stored in the storage device 36 of the computer 32 by the arithmetic unit 35. However, a specific circuit having various functions may be provided in the magnetic resonance imaging apparatus 20 instead of at least a part of the program.

  FIG. 2 is a functional block diagram of the computer 32 shown in FIG.

  The computing device 35 of the computer 32 functions as an imaging condition setting unit 40, an image reconstruction unit 41, and an image processing unit 42 by executing a program stored in the storage device 36. The image processing unit 42 includes an addition region setting unit 42A, an image addition unit 42B, and a display processing unit 42C. The storage device 36 functions as a k-space data storage unit 43 and an image data storage unit 44.

  The imaging condition setting unit 40 has a function of setting imaging conditions including a pulse sequence based on instruction information from the input device 33 and outputting the set imaging conditions to the sequence controller 31. In particular, the imaging condition setting unit 40 has a function of setting imaging conditions for collecting NMR signals for generating image data of a plurality of frames at the same slice position of the subject P with different imaging parameters. That is, the imaging condition setting unit 40 is configured to be able to set imaging conditions for collecting multi-echo data from the same slice position with a plurality of different imaging parameters such as TE.

  FIG. 3 is a diagram illustrating an example of an FE sequence for collecting multi-echo data with different TEs.

  In FIG. 3, RF is an RF pulse, Gss, Gpe, and Gro are a gradient magnetic field pulse for slice selection, a gradient magnetic field pulse for phase encoding (PE), and a gradient magnetic field for readout (RO), respectively. Pulse, ECHO indicates NMR echo signal.

As shown in FIG. 3, FE sequence slice selection gradient magnetic field pulse Gss, PE gradient magnetic field pulse Gpe, and RO are used so that a plurality of echo signals are collected from a common slice at different TEs after application of an RF pulse. A gradient magnetic field pulse Gro can be set. FIG. 3 shows an example of an FE sequence that collects four echo signals from a common slice in _four TEs (TE ₁ , TE ₂ , TE ₃ , TE ₄ ).

  In addition to the FE sequence illustrated in FIG. 3, an arbitrary pulse sequence such as a spin echo (SE) sequence can be set as the imaging condition. Each TE of a sequence for performing multi-echo data collection is determined according to a target image contrast together with a repetition time (TR) of the sequence. Specifically, MR image data having different contrasts such as T2 * weighted image data, lateral relaxation (T2) weighted image data, and vertical relaxation (T1) weighted image data can be collected according to the length of TE. .

  For example, if the TR is set shorter than the T1 value of the tissue and the TE is set sufficiently shorter than the T2 value in the SE sequence, T1-weighted image data can be obtained. On the other hand, T2 weighted image data can be obtained by setting TR as long as the longitudinal magnetization of the tissue recovers and setting TE as long as the difference in T2 value appears in each tissue in the SE sequence. In addition, T2 * weighted image data can be obtained by setting TR and TE sufficiently long so that a difference in T2 * value corresponding to the apparent T2 value in each tissue appears in the FE sequence.

  When collecting multiple frames of image data as T2 weighted image data or T2 * weighted image data, imaging conditions for collecting multi-echo data from the same slice position with different TEs are set. That is, the imaging conditions are set so that a plurality of frames of image data are collected as T1 weighted image data or T2 * weighted image data corresponding to MR signals collected at different TEs.

  On the other hand, when collecting multiple frames of image data as T1-weighted image data, at least one of the inversion time (TI: inversion time) and the flip angle (FA: flip angle) of the RF excitation pulse is set to a different value from each other. Imaging conditions for collecting multi-echo data from the slice position are set. That is, the imaging conditions are set such that a plurality of frames of image data are collected as a plurality of frames of T1-weighted image data corresponding to MR signals collected with at least one of TI and FA as different values. TI is the time from the inversion recovery (IR) pulse to the RF excitation pulse.

  As described above, when T2 weighted image data or T2 * weighted image data is collected, an imaging condition for changing the imaging parameter TE for each TR is set. On the other hand, when collecting T1-weighted image data, an imaging condition is set in which at least one of the imaging parameters TI and FA is changed for each TR.

  The image reconstruction unit 41 acquires the NMR signals collected by the imaging scan under the imaging conditions set in the imaging condition setting unit 40 from the sequence controller 31 and arranges them in the k space formed in the k space data storage unit 43. A function for reconstructing image data by fetching k-space data from the k-space data storage unit 43 and performing an image reconstruction process including Fourier transform (FT), an image obtained by reconstruction It has a function of writing data to the image data storage unit 44.

  An NMR signal to be subjected to image reconstruction processing is collected for a plurality of frames with different imaging parameters such as TE. Therefore, as a result of the image reconstruction process, MR image data of a plurality of frames corresponding to different imaging parameters is generated. Accordingly, the image data storage unit 44 stores image data at the same slice position of a plurality of frames corresponding to different imaging parameters.

  As described above, the hardware including the static magnetic field magnet 21, the gradient magnetic field coil 23, and the RF coil 24, the control system 25, and the components including the image reconstruction unit 41 of the computer 32 cooperate with each other according to the imaging conditions. An imaging system for performing MR imaging of the specimen P is formed. In particular, this imaging system has a function of collecting image data of a plurality of frames at the same slice position of the subject P by MR imaging in correspondence with NMR signals collected under different imaging conditions. The detailed configuration of the imagen system is not limited to the configuration described above, and various types of systems are known.

  The image processing unit 42 has a function of performing necessary image processing on the image data fetched from the image data storage unit 44 and causing the display device 34 to display the image data. In particular, the image processing unit 42 adds pixel values in a specific region of at least one frame of other image data to one frame of image data selected from image data of a plurality of frames corresponding to different imaging parameters such as TE. It has a function of generating image data for display by image processing including processing for addition. That is, the image processing unit 42 performs addition processing by limiting the image data of a plurality of frames corresponding to different imaging parameters to only some pixels, thereby combining the image data of the plurality of frames corresponding to the different imaging parameters. Is configured to generate

  The addition area setting unit 42A has a function of setting a specific area to which pixel values are to be added between image data of a plurality of frames corresponding to different imaging parameters. In addition, the image addition unit 42B has a function of adding pixel values in a specific region set by the addition region setting unit 42A to base image data selected from image data of a plurality of frames corresponding to different imaging parameters. Have.

  The specific area to which the pixel value is to be added is determined so that a desired image contrast is obtained in the combined image data after the pixel value is added.

  As a first example, the specific region to which the pixel value is to be added is based on a time constant representing the attenuation of the signal acquired for each pixel based on the pixel values of the image data of a plurality of frames corresponding to different imaging parameters. Can be specified. In other words, image signals at corresponding pixel positions between image data of a plurality of frames correspond to different imaging parameters. Therefore, if the intensity of the image signal at the corresponding pixel position between the image data of a plurality of frames is plotted in the direction of the imaging parameter axis such as the TE axis, a time constant representing the attenuation of the image signal can be obtained for each pixel.

  If the imaging condition is a condition for collecting T1-weighted image data, the time constant is a T1 value. If the imaging condition is a condition for collecting T2-weighted image data, the time constant is a T2 value. If the imaging condition is a condition for collecting T2 * weighted image data, the time constant is a T2 * value. Therefore, it is possible to specify a specific region to which pixel values are to be added with the time constant as the T1 value, T2 value, or T2 * value.

  Specifically, when a time constant such as a T1 value, a T2 value, or a T2 * value is obtained, a pixel area extracted by threshold processing for the time constant, such as a pixel area whose time constant is greater than or exceeds the threshold, It can be a specific area to which a value is added. For example, to collect T2 * weighted image data, if imaging is performed with TE set to 5, 10, 15, 20, 25 [ms], only pixels that satisfy T2 * ≧ 50 [ms] Can be set as an area to be added. Similarly, when T1-weighted image data or T2-weighted image data is collected, a pixel region whose T1 value or T2 value is in an appropriate range can be extracted by threshold processing.

  As described above, when the addition processing is performed between the image data of a plurality of frames only for pixels in which the time constant is in an appropriate range, noise and artifacts are suppressed at least in the pixel region targeted for the addition processing, and the SNR is reduced. Improved composite image data can be obtained. Moreover, it is possible to obtain composite image data using only the pixel values in the pixel region corresponding to the time constant set to obtain the desired contrast. As a result, image data having good contrast can be generated.

  As a second example of a method for determining a specific region to which pixel values are to be added, there is a method in which a region in a specific tissue of interest is a specific region. The specific tissue can be extracted by pattern matching based on anatomical knowledge with respect to image data of at least one frame of image data of a plurality of frames corresponding to different imaging parameters such as TE. Therefore, a known image recognition process necessary for pattern matching such as an edge extraction process for image data is executed in the addition area setting unit 42A. As a specific example, when the cervical crossing image data is captured, the spinal cord can be extracted, and the region occupied by the spinal cord can be set as a specific region to be added with pixel values.

  As a third example of a method for determining a specific area to be added with pixel values, there is a method of associating a specific area with imaging conditions of image data of a plurality of frames to be added. As a specific example, if the imaging slice is a cervical crossing slice, the central portion of the image data determined to include the spinal cord region can be set as a specific region to be added with pixel values.

  In addition, as a fourth example of a method for determining a specific area to which a pixel value is to be added, a specific area may be designated by operating the input device 33. In this case, an image for spatially manually setting a specific area to which pixel values are to be added by operating the input device 33 is displayed on the display device 34 as a user interface.

  Image data to be added with pixel values in a specific region, that is, reference image data can be selected from image data of a plurality of frames corresponding to different imaging parameters by an arbitrary method.

  For example, the image adding unit 42B automatically selects image data having a maximum contrast-to-noise ratio (CNR) in a specific tissue from a plurality of frames of image data as a target of addition processing. Can be configured. In this case, as described above, a specific tissue can be extracted by pattern matching based on anatomical knowledge with respect to image data of at least one frame of image data of a plurality of frames corresponding to different imaging parameters.

  As another example, the image adding unit 42B is configured to select the image data having the maximum CNR in the region specified by the operation of the input device 33 from the image data of a plurality of frames as the processing target to be added. You can also. That is, the image data having the maximum CNR in the ROI manually designated by the user by operating the input device 33 can be set as the reference image data to be added with the pixel value.

  As yet another example, the image addition unit 42B may be configured to select image data designated by the operation of the input device 33 from a plurality of frames of image data as a target of the addition process. That is, it can be manually designated by the user. As a specific example, if imaging is performed with TE = 5, 10, 15, 20, 25 [ms] to collect T2 * weighted image data, an image corresponding to TE = 10 Data can be set as reference image data to be added with pixel values.

  The display processing unit 42C of the image processing unit 42 has a function of performing necessary display processing on the composite image data generated by the pixel value addition processing in the image addition unit 42B and causing the display device 34 to display the composite image data.

  Next, the operation and action of the magnetic resonance imaging apparatus 20 will be described.

  FIG. 4 is a flowchart showing the flow of imaging by the magnetic resonance imaging apparatus 20 shown in FIG.

  First, the subject P is set on the bed 37 in advance, and a static magnetic field is formed in the imaging region of the static magnetic field magnet 21 (superconducting magnet) excited by the static magnetic field power supply 26. Further, a current is supplied from the shim coil power supply 28 to the shim coil 22, and the static magnetic field formed in the imaging region is made uniform.

  Next, in step S1, an imaging scan of the subject P is executed by a multi-echo data acquisition sequence for acquiring NMR signals with different imaging parameters from the same slice position. For this purpose, the imaging condition setting unit 40 sets imaging conditions including a pulse sequence for collecting multi-echo data with different TEs as exemplified in FIG.

  Then, when a scan start instruction is given from the input device 33 to the imaging condition setting unit 40, the imaging condition setting unit 40 outputs imaging conditions including a pulse sequence to the sequence controller 31. The sequence controller 31 drives the gradient magnetic field power source 27, the transmitter 29, and the receiver 30 according to the imaging conditions to form a gradient magnetic field in the imaging region where the subject P is set, and generates an RF signal from the RF coil 24. Let

  Therefore, an NMR signal generated by nuclear magnetic resonance inside the subject P is received by the RF coil 24 and given to the receiver 30. The receiver 30 receives the NMR signal from the RF coil 24, executes necessary signal processing, and then performs A / D (analog to digital) conversion to generate raw data that is an NMR signal of digital data. The receiver 30 gives the generated raw data to the sequence controller 31. The sequence controller 31 provides the raw data to the image reconstruction unit 41, and the image reconstruction unit 41 arranges the raw data as k-space data in the k-space formed in the k-space data storage unit 43.

  Next, in step S <b> 2, the image reconstruction unit 41 takes in k-space data from the k-space data storage unit 43 and performs image reconstruction processing. Thereby, a plurality of frames of image data corresponding to different imaging parameters such as TE are generated. The generated image data is stored in the image data storage unit 44 as necessary.

  Next, in step S3, the addition area setting unit 42A sets a pixel area that is a pixel value addition target between image data of a plurality of frames corresponding to different imaging parameters. For example, an area in which a time constant such as a T2 * value calculated based on a temporal change of a pixel value falls within an appropriate range, a specific tissue extracted by template matching, a specific area associated with an imaging condition, or an input device The area designated by the operation 33 is set as a pixel area to which pixel values are to be added.

  Next, in step S4, the image addition unit 42B adds the pixel value in the pixel region limited by the addition region setting unit 42A to reference image data selected from a plurality of frames of image data corresponding to different imaging parameters. As a result, local composite image data of a plurality of frames of image data is generated.

  Next, in step S5, the display processing unit 42C performs necessary display processing on the composite image data generated by the image adding unit 42B and causes the display device 34 to display the composite image data. Thereby, the MR image for diagnosis in which the SNR is improved and the contrast is improved by the addition process is displayed on the display device 34.

  That is, the magnetic resonance imaging apparatus 20 as described above collects image data of a plurality of frames corresponding to different imaging parameters such as TE from the same slice position of the subject P, and performs addition processing on only specific pixel areas. It is what I did.

  For this reason, according to the magnetic resonance imaging apparatus 20, it is possible to improve the contrast and image quality within the ROI of the MR image. This is particularly effective when capturing T2-weighted images and T2 * -weighted images where improvement of SNR is important.

  For example, setting a long TE to obtain a T2 * weighted image with good contrast and simply performing an addition process to improve SNR results in the synthesis of artifacts due to susceptibility, There is a problem that image quality deteriorates.

  On the other hand, in the magnetic resonance imaging apparatus 20, only the pixel region having a long T2 * value is added. Therefore, it is possible to obtain a T2 * weighted image with improved contrast and SNR while suppressing artifacts.

  Although specific embodiments have been described above, the described embodiments are merely examples, and do not limit the scope of the invention. The novel methods and apparatus described herein can be implemented in a variety of other ways. Various omissions, substitutions, and changes can be made in the method and apparatus described herein without departing from the spirit of the invention. The appended claims and their equivalents include such various forms and modifications as are encompassed by the scope and spirit of the invention.

20 Magnetic Resonance Imaging Device 21 Magnet for Static Magnetic Field 22 Shim Coil 23 Gradient Magnetic Field Coil 24 RF Coil 25 Control System 26 Static Magnetic Field Power Supply 27 Gradient Magnetic Field Power Supply 28 Shim Coil Power Supply 29 Transmitter 30 Receiver 31 Sequence Controller 32 Computer 33 Input Device 34 Display Device 35 arithmetic device 36 storage device 37 bed 40 imaging condition setting unit 41 image reconstruction unit 42 image processing unit 42A addition region setting unit 42B image addition unit 42C display processing unit 43 k-space data storage unit 44 image data storage unit P subject

Claims (11)

Imaging means for collecting a plurality of frames of image data at the same slice position of the subject by magnetic resonance imaging in correspondence with magnetic resonance signals collected under different imaging conditions;
Display image data is generated by image processing including processing of adding pixel values in a specific region of at least one frame of other image data to one frame of image data selected from the plurality of frames of image data. Image processing means;
A magnetic resonance imaging apparatus comprising:   The image processing means is a process of adding the pixel values in the specific region specified based on a time constant representing attenuation of a signal acquired for each pixel based on pixel values of the image data of the plurality of frames. The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is configured to perform.   The magnetic resonance imaging apparatus according to claim 2, wherein the image processing unit is configured to specify the specific region using the time constant as a longitudinal relaxation time, a lateral relaxation time, or a T2 star value.   The image processing means is configured to perform a process of adding pixel values in a specific tissue extracted by pattern matching based on anatomical knowledge with respect to image data of at least one frame of the image data of the plurality of frames. Item 2. The magnetic resonance imaging apparatus according to Item 1.   The magnetic resonance imaging apparatus according to claim 1, wherein the image processing unit is configured to perform a process of adding pixel values in a specific region associated with an imaging condition of the image data of the plurality of frames.   The magnetic resonance imaging apparatus according to claim 1, wherein the image processing unit is configured to perform a process of adding pixel values in a specific region designated by an operation of the input device.   The image processing means adds the image data having a maximum contrast-to-noise ratio in a specific tissue extracted by pattern matching based on anatomical knowledge on image data of at least one frame of the image data of the plurality of frames. The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is configured to automatically select the image data of the plurality of frames as an object to be processed.   The image processing means is configured to select image data having a maximum contrast-to-noise ratio in a region designated by an operation of the input device from the image data of the plurality of frames as the target of the addition process. The magnetic resonance imaging apparatus according to claim 1.   7. The image processing unit according to claim 1, wherein the image processing unit is configured to select image data designated by an operation of an input device from the image data of the plurality of frames as an object to be added. The magnetic resonance imaging apparatus described.   The imaging means is configured to collect the plurality of frames of image data as transverse relaxation enhanced image data or T2 star enhanced image data of a plurality of frames corresponding to magnetic resonance signals collected at different echo times. Item 10. The magnetic resonance imaging apparatus according to any one of Items 1 to 9.   The imaging means includes a plurality of frames of longitudinal relaxation enhanced image data corresponding to magnetic resonance signals collected with at least one of an inversion time from an inversion recovery pulse to a radio frequency excitation pulse and a flip angle of the radio frequency excitation pulse as different values. The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is configured to collect image data of the plurality of frames.

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