JP6533571B2 - Magnetic resonance imaging apparatus and imaging method - Google Patents

Description

  The present invention relates to magnetic resonance imaging (hereinafter referred to as "MRI") technology, and in particular, acquires information (hemodynamic information) on the blood flow of a subject and uses the hemodynamic information to further enhance the technology. The present invention relates to a technique for generating various hemodynamic information.

  An MRI apparatus measures nuclear magnetic resonance (NMR) signals generated by nuclear spins that constitute tissues of a subject, in particular, a human body, and forms or functions two-dimensionally or three-dimensionally in the head, abdomen, limbs, etc. Is an apparatus for imaging. In imaging, different phase encoding is added to the NMR signal by the gradient magnetic field and frequency encoding is performed to measure it as time-series data. The measured NMR signal is reconstructed into an image by being subjected to two-dimensional or three-dimensional Fourier transform.

  In recent years, for example, evaluation of hemodynamics of a site such as the brain has been made using blood perfusion images and related information. Images used for evaluation of hemodynamics include, for example, cerebral blood volume (CBV) images, cerebral blood flow (CBF) images, oxygen uptake rate (Oxygen Extraction Fraction) when the site is the brain. There are OEF images, cerebral metabolic rate of oxygen (CMRO2) images, mean transit time (MTT) images, and the like.

  By the way, in high magnetic field MRI of 1.5 T or more, a blood perfusion image (Perfusion Weighted Imaging: PWI), a quantitative susceptibility map (Quantitative Susceptibility Map: QSM), a diffusion weighted image (DWI), etc. are generated. The protocol has been put to practical use.

  For PWI, ASL-PWI (Arterial Spin) that visualizes hemodynamics by acquiring blood labeled image (label image) and non-labeled image (control image) without contrast agent and taking the difference between the two. There is a method called Labeling-PWI: arterial magnetization label PWI) (see, for example, Patent Documents 1, 2, and 3). And there exists a technique which acquires a CBF image from this ASL-PWI (for example, refer nonpatent literature 1, 2).

  The QSM executes an imaging sequence for acquiring SWI (Susceptibility Weighted Imaging: magnetic susceptibility weighted image), obtains a phase map of tissue from the obtained phase image, and obtains it by the inverse problem (for example, Non-Patent Document 3, 4, Patent Document 4). There is a technique called QMS-OEF which images the distribution of OEF from this QSM. In addition, there is a technique of obtaining a CMRO2 image from QSM in cerebral perfusion in two different states, and further obtaining an OEF image from this CMRO2 image (see, for example, Non-Patent Document 5). Non-Patent Document 5 also discloses a technique for calculating a CBV image from a CBF image in the process of calculating a CMRO 2 image.

  There is also a technique of acquiring SWI images in a plurality of different states, such as at rest and under load, and using them to obtain an OEF image (see, for example, Non-Patent Document 6). On the other hand, there is also a technique for obtaining an OEF image only from an image obtained at rest (see, for example, Non-Patent Document 7).

  In addition, there is a technique of generating an IVIM (Intra-Voxel Incoherent Motion) image reflecting perfusion, from DWI, and obtaining a CBV image from this IVIM image (see, for example, Non-Patent Documents 8 and 9). Also, under certain assumptions, there is a method of obtaining a CBV image, an MTT image, and a CBF image from an IVIM image (see Non-Patent Document 8, Table 1). Among the images obtained from IVIM images, CBV (f) has the highest correlation with DCS (Dynamic Susceptibility Contrast). The accuracy of the MTT image obtained from the IVIM image is not good (Non-Patent Document 8, FIG. 10).

U.S. Pat. No. 5,846,197 U.S. Patent No. 7,545,142 U.S. Patent No. 6,285,900 International Publication No. 2014/076808

Nicholas A. et al. “Arterial spin labeling MRI: Clinical applications in the brain”, Journal of magnetic resonance imaging 2014, Article first published online: 19 SEP 2014, DOI: 10.1002 / jmri. 24751 p1-p16 E. L. Barbier, et al. “Methodology of brain perfusion imaging”, Journal of magnetic resonance imaging 2001 13 p496-520 C. Lin et al. “Susceptibility -weighted imaging and quantitative mapping in the brain”, Journal of magnetic resonance imaging 2014, Article first published online: 1 OCT 2014, DOI: 10.102 / jmri.24768 p1-19 R. Sato et al. “Quantitative susceptibility mapping with a combination of different regularization parameters”, ISMRM 2014 p3179 J. Zhang et. Al. “Quantitative mapping of cerebral metabolic rate of oxygen (CMRO2) using quantitative susceptibility mapping”, Magnetic resonance in medicine 2014 Article first published online: 26 SEP 2014, DOI: 10.10.02 mrm. Y. Zaitsu et al. “Mapping of cerebral oxygen extraction fraction changes with susceptibility-weighted phase imaging”, Radiology 2011 volume 261 Number 3 p930-936 K. Kudo et al. “Oxygen extraction fraction measurement using quantitative susceptibility mapping in patients with chronic cerebral ischemia: comparison with positron emission tomography”, ISMRM 2014 p3272 Christian Federau et al. “Measuring brain perfusion with intra-voxel incoherent motion (IVIM): Initial clinical experience”, Journal of magnetic resonance imaging 2014 39 p624-632 D. Le Bihan, R. Turner “The capillary network: A link between IVIM and classical perfusion”, Magnetic resonance in medicine 1992 27 p171-178

  As mentioned above, the multiple protocols of MRI can yield many different images needed to assess the hemodynamics of a particular site, eg, the brain.

However, for example, in the technique disclosed in Non-Patent Document 5, a CBV image is obtained by multiplying a CBF image by a coefficient obtained by Positron Emission Tomography (PET). As described above, in order to obtain the various types of images from the images obtained by the MRI apparatus, coefficients obtained from the measurement results of PET are required. For this reason, in general, CBV, CBF, and OEF are often measured by PET as they are in clinical practice. In particular, OEF often uses ¹⁵ O-PET, which can provide useful diagnostic information, such as being able to image areas of poor perfusion. However, because ¹⁵ O-PET uses short-lived radioactive isotopes as contrast agents, it requires an accelerator to make contrast agents for examination, it is a highly invasive examination, and the need for examination is expensive, etc. Therefore, although the clinical usefulness is high, it has rather limited spread.

  Further, the CMRO2 image is calculated from a plurality of states, for example, QSM at rest and under load. For this reason, it is necessary to perform imaging of QSM in both states, which places a heavy load on the patient. In addition, a method of obtaining a CMRO2 image from an ASL-PWI image and a QSM-OEF image has not been proposed. In addition, a method for obtaining an MTT image from calculation of an ASL-PWI image and an IVIM-CBV image has not been proposed in the range investigated by the inventor.

  The present invention has been made in view of the above circumstances, and provides a technique for acquiring an image (blood flow parameter) necessary for evaluating hemodynamics of a predetermined site only by a low invasive test. With the goal.

In this embodiment, neither a radioisotope (eg, ¹⁵ O) nor an MRI contrast agent (eg, Gd) is used, and only a plurality of types of imaging using no contrast agent by the MRI apparatus can be performed on a predetermined site. Acquire images necessary to evaluate hemodynamics. For example, when the site is a brain, ASL-PWI imaging, QSM imaging, IVIM imaging are performed, and from the results, CBF image, OEF image, CBV image, CMRO2 image, MTT image necessary for evaluating the hemodynamics of the brain Get

  According to the present invention, it is possible to acquire an image (blood flow parameter) necessary to evaluate hemodynamics of a predetermined site only by a low invasive test.

1 is a block diagram of an entire configuration of an MRI apparatus according to a first embodiment. (A) is a functional block diagram of the control processing unit of the first embodiment, and (b) is a functional block diagram of the control processing unit of the third embodiment. It is an explanatory view for explaining a flow of hemodynamic calculation processing of a first embodiment. It is a flowchart of the imaging process of 1st embodiment. (A) And (b) is explanatory drawing for demonstrating the ASL-PWI sequence example of 1st embodiment. (A) And (b) is explanatory drawing for demonstrating the QSM sequence example of 1st embodiment. It is an explanatory view for explaining an example of an IVIM sequence of a first embodiment. It is explanatory drawing for demonstrating the IVIM image creation method of 1st embodiment. It is an explanatory view for explaining CMRO2 calculation processing of a first embodiment. It is an explanatory view for explaining MTT calculation processing of a first embodiment. It is a flowchart of the 1st example of the imaging process of 2nd embodiment. It is a flowchart of the 2nd example of the imaging process of 2nd embodiment. It is an explanatory view for explaining image pick-up processing and luminosity amendment processing of a third embodiment. It is an explanatory view for explaining image pick-up processing and static magnetic field distortion amendment processing of a third embodiment.

<< First Embodiment >>
A first embodiment of the present invention will be described. In all the drawings for describing the embodiments of the present invention, components having the same function are denoted by the same reference symbols unless otherwise specified, and the repetitive description thereof will be omitted.

[Device configuration]
First, an overview of an example of an MRI apparatus according to the present embodiment will be described based on FIG. FIG. 1 is a block diagram showing the entire configuration of an embodiment of the MRI apparatus of the present embodiment.

  The MRI apparatus 100 of the present embodiment obtains a tomographic image of a subject using NMR phenomenon, and as shown in FIG. 1, a static magnetic field generation unit 120, a gradient magnetic field generation unit 130, a sequencer 140, A high frequency magnetic field generation unit (hereinafter, transmission unit) 150, a high frequency magnetic field detection unit (hereinafter, reception unit) 160, and a control processing unit 170 are provided.

  The static magnetic field generation unit 120 generates a uniform static magnetic field in the space around the object 101 in the direction perpendicular to the body axis in the case of the vertical magnetic field type, and in the body axis direction in the horizontal magnetic field type. And a static magnetic field generation source of a permanent magnet system, a normal conduction system, or a superconducting system, which is disposed around the object 101.

  The gradient magnetic field generating unit 130 is a gradient magnetic field power source for driving the gradient magnetic field coils 131 wound in three axial directions of X, Y and Z, which are coordinate systems (apparatus coordinate system) of the MRI apparatus 100 132, and applies gradient magnetic fields Gx, Gy, and Gz in three axial directions of X, Y, and Z by driving gradient magnetic field power sources 132 of respective gradient magnetic field coils 131 according to an instruction from a sequencer 140 described later. . At the time of imaging, slice direction gradient magnetic field pulses (Gs) are applied in the direction orthogonal to the slice plane (imaging cross section) to set the slice plane with respect to the subject 1, and the remaining 2 orthogonal to the slice plane Position encodement information of each direction is encoded in an echo signal by applying phase encode direction gradient magnetic field pulses (Gp) and frequency encode direction gradient magnetic field pulses (Gf) in one direction.

  The transmitting unit 150 causes a nuclear magnetic resonance (NMR) phenomenon to occur in nuclear spins of atoms constituting the living tissue of the subject 101, a high frequency magnetic field pulse (hereinafter referred to as "RF pulse") in the subject 101. And includes a high frequency oscillator (synthesizer) 152, a modulator 153, a high frequency amplifier 154, and a high frequency coil (transmission coil) 151 on the transmission side. The high frequency oscillator 152 generates an RF pulse. The modulator 153 amplitude modulates the output RF pulse in accordance with a command from the sequencer 140. The high frequency amplifier 154 amplifies this amplitude-modulated RF pulse and supplies it to a transmission coil 151 disposed in the vicinity of the subject 101. The transmission coil 151 irradiates the subject RF with the supplied RF pulse.

  The receiving unit 160 detects a nuclear magnetic resonance signal (echo signal, NMR signal) emitted by nuclear magnetic resonance of nuclear spins constituting the living tissue of the subject 101, and a high-frequency coil (receiving coil) on the receiving side 161, a signal amplifier 162, a quadrature phase detector 163, and an A / D converter 164. The receiving coil 161 is disposed close to the subject 101 and detects an NMR signal of the response of the subject 101 induced by the electromagnetic wave emitted from the transmitting coil 151. The detected NMR signal is amplified by the signal amplifier 162 and then divided into two orthogonal signals by the quadrature phase detector 163 at a timing according to a command from the sequencer 140, each of which is digitized by the A / D converter 164. It is converted into a quantity and sent to the control processing unit 170.

  If the transmission coil 151 and the gradient magnetic field coil 131 face the subject 101 in the static magnetic field space of the static magnetic field generation unit 120 into which the subject 101 is inserted, the transmission coil 151 and the gradient magnetic field coil 131 face the subject 101. It is installed so as to surround the subject 101. In addition, the receiving coil 161 is disposed to face or surround the subject 101.

  The sequencer 140 applies an RF pulse and a gradient magnetic field pulse according to an instruction from the control processing unit 170, and instructs each unit so that an echo signal generated by the object 101 is measured. Specifically, in accordance with an instruction from the control processing unit 170, various commands necessary for collecting data of tomographic images of the subject 101 are transmitted to the transmitting unit 150, the gradient magnetic field generating unit 130, and the receiving unit 160.

  The control processing unit 170 controls the entire MRI apparatus 100, performs calculations such as various data processing, and displays and saves processing results, and includes a CPU 171, a storage device 172, a display device 173, and an input device 174. The storage device 172 is configured by an internal storage device such as a hard disk and an external storage device such as an external hard disk, an optical disk, or a magnetic disk. The display device 173 is a display device such as a CRT or liquid crystal. The input device 174 is an interface for inputting various control information of the MRI apparatus 100 and control information of processing performed by the control processing unit 170, and includes, for example, a track ball or a mouse and a keyboard. The input device 174 is disposed in proximity to the display device 173. The operator interactively inputs instructions and data necessary for various processes of the MRI apparatus 100 through the input device 174 while looking at the display device 173. Note that the display device 173 may also function as the input device 174, such as a touch panel.

  The CPU 171 implements the processing of the control processing unit 170 such as control of the operation of the MRI apparatus 100 and various data processing by executing a program stored in advance in the storage device 172 according to an instruction input by the operator. The instruction to the sequencer 140 is performed in accordance with a pulse sequence (imaging sequence) previously stored in the storage device 172. Also, for example, when data from the receiving unit 160 is input to the control processing unit 170, the CPU 171 executes signal processing, image reconstruction processing, and the like, and displays the tomographic image of the object 101 as a result thereof. , And stored in the storage unit 172.

  At present, among the imaging target nuclides of the MRI apparatus, those spreading widely in the clinic are hydrogen nuclei (protons) which are the main constituent substances of the object 101. The MRI apparatus 100 two-dimensionally or three-dimensionally displays the shape or function of the human head, abdomen, limbs, etc. by imaging information on the spatial distribution of proton density and the spatial distribution of relaxation time of the excited state. Take an image.

[Function configuration]
In the present embodiment, as described above, an image group (blood flow parameter) capable of evaluating hemodynamics of a predetermined site is acquired only by a low invasive examination method. Specifically, a necessary image group is calculated from data obtained by a plurality of types of MRI imaging without using a contrast agent.

  In order to realize this, the control processing unit 170 of this embodiment measures echo signals from a predetermined area of the subject 101 according to a predetermined imaging sequence that does not use a contrast agent, as shown in FIG. An imaging unit 210 for obtaining a reconstructed image from the obtained echo signal; a sequence image acquisition unit 220 for performing predetermined processing on the reconstructed image to calculate a sequence image; and image processing for the sequence image; And an image processing unit 230 for calculating a hemodynamic image for evaluating hemodynamics of a predetermined region included in the region. The image processing unit 230 holds the calculated image in the storage unit 172 and displays the image on the display unit 173.

  Each function realized by the control processing unit 170 is realized by the CPU 171 of the control processing unit 170 loading a program stored in advance in the storage device 172 into the memory and executing it. Further, all or part of the functions may be realized by hardware such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). Further, various data used for processing of each function and various data generated during the processing are stored in the storage device 172.

[Overview of this embodiment]
In the present embodiment, the imaging unit 210 executes a first imaging sequence and a second imaging sequence different from the first imaging sequence. Then, the sequence image acquisition unit 220 calculates a first sequence image from the reconstructed image obtained by the first imaging sequence, and calculates a second sequence image from the reconstructed image obtained by the second imaging sequence. .

  Then, the image processing unit 230 calculates a first hemodynamic image and a second hemodynamic image different from the first hemodynamic image from the first sequence image and the second sequence image. And calculating a fourth hemodynamic image different from the first hemodynamic image and the second hemodynamic image from the first hemodynamic image and the second hemodynamic image.

  The imaging unit 210 further executes a third imaging sequence different from the first imaging sequence and the second imaging sequence, and the sequence image acquiring unit 220 generates a reconstructed image acquired by the third imaging sequence. The image reconstructed from the image is subjected to predetermined processing to calculate a third sequence image, and the image processing unit 230 calculates the first hemodynamic image and the second circulation from the third sequence image. A third hemodynamic image different from the dynamic image is calculated, and the first hemodynamic image and one of the second hemodynamic image and the third hemodynamic image are used to calculate the first hemodynamic image. A fifth hemodynamic image different from any of the hemodynamic image, the second hemodynamic image, the third hemodynamic image, and the fourth hemodynamic image may be calculated.

  Hereinafter, in the present embodiment, a target site for evaluating hemodynamics is a brain, and as shown in FIG. 3, a first imaging sequence is an ASL-PWI sequence 300, and a second imaging sequence is a QSM sequence (QSM is obtained A third imaging sequence is an IVIM sequence (imaging sequence for acquiring an IVIM) 500, a first sequence image is an ASL-PWI image 310, and a second sequence image Is the QSM image 410, the third sequence image is the IVIM image 510, the first hemodynamic image is the cerebral blood flow (ASL-CBF) image 330, and the second hemodynamic image is the oxygen uptake rate (QMS-OEF) image 430 and the third hemodynamic image is brain blood volume (IVIM-CBV) image 530 The fourth hemodynamic image, cerebral oxygen consumption and (CMRO2) image 620, the fifth hemodynamic image, will be described as an example a case in which the mean transit time (MTT) image 640. Hereinafter, each function of the control processing unit 170 will be described according to FIG.

[Imaging unit]
First, imaging processing 200 by the imaging unit 210 will be described. In the present embodiment, the imaging unit 210 executes the ASL-PWI sequence 300, the QSM sequence 400, and the IVIM sequence 500 to obtain a reconstructed image. FIG. 4 is a flowchart of imaging processing 200 by the imaging unit 210. In addition, the execution order of these sequences does not matter.

[ASL-PWI imaging]
First, the imaging unit 210 performs ASL-PWI imaging according to the ASL-PWI sequence 300 (step S1101). Then, the imaging unit 210 obtains, from the obtained echo signal, a control image (Control) 311 that does not label blood and an image (label image: Spin labeled) 312 that labels blood.

  Here, the ASL-PWI sequence 300 used for ASL-PWI imaging will be described. As described above, ASL-PWI imaging is imaging in which hemodynamics are depicted by acquiring the control image 311 and the label image 312 and taking the difference between the two.

  As shown in FIG. 5A, the ASL-PWI sequence 300 applies a label pulse 301 to execute an imaging sequence (image acquisition sequence) 302 for acquiring image data, and a control pulse, and a control pulse. And a control imaging unit 305 that executes an image acquisition sequence 302 by applying 304. In the ASL-PWI sequence 300, imaging is performed with the imaging by the labeling imaging unit 303 and the imaging by the control imaging unit 305 as one set.

  As the ASL-PWI sequence 300, for example, a 2D flow sensitive alternating inversion recovery (FAIR) sequence, a 2D pCASL (pseudo-continuous arterial spin labeling) sequence, or the like is used.

  In FAIR, after applying an inversion pulse, an imaging sequence for executing an image acquisition sequence and an imaging sequence for executing an image acquisition sequence are performed as one set without applying the inversion pulse (for example, Seong-Gi Kim, “ Quantification of relative cerebral blood flow change by flow-sensitive alternating inversion recovery (FAIR) technique: application to functional mapping ”Magnetic resonance in Medicine, 1995 34 (p. 293-301).

  Further, in the ASL-PWI sequence 300, an imaging sequence used as the image acquisition sequence 302 is, for example, a GrE-EPI (Gradient Echo-echo planar imaging) sequence. An example of this GrE-EPI sequence 350 is shown in FIG. 5 (b).

  In the drawing, RF, Gs, Gp, and Gf respectively indicate application axes of an RF pulse, a slice selection gradient magnetic field pulse, a phase encoding gradient magnetic field pulse, and a frequency encoding gradient magnetic field pulse. Hereinafter, the same applies to all the sequence diagrams in the present specification.

  As shown in the figure, the EPI sequence 350 applies the RF pulse 351 together with the slice selection gradient magnetic field pulse 352, then reverses the readout gradient magnetic field pulse 354 while changing the gradient magnetic field pulse 353 for applying phase encoding. , Is a sequence that creates multiple gradient echoes 355 and fills multiple lines in k-space. Imaging parameters include, for example, 64x64 matrix, FOV (field of view) = 24x24 cm, spatial resolution 3.8 x 3.8 mm, slice thickness 5 mm, TI (inversion time) = 1.4 s, inversion slab 15 mm, image Use 40 additions.

  The ASL-PWI sequence 300 is not limited to the above configuration. As long as the ASL-CBF image 330 can be acquired appropriately, it may be, for example, 3D.

  In addition, it is desirable to add a pulse for suppressing blood to the ASL-PWI sequence 300. Pulses for suppressing blood include, for example, MPG (Motion Probing Gradient) pulses. The MPG pulse is applied between the inversion pulse and the image acquisition sequence in the case of FAIR. At this time, for example, the b value representing the strength of the application of the MPG pulse is about 10.

  By adding a pulse that suppresses blood, there is an advantage that the blood signal can be suppressed in the later-described ASL-CBF image 330 calculated from the ASL-PWI sequence 300.

[QSM imaging]
Next, the imaging unit 210 performs QSM imaging according to the QSM sequence 400 (step S1102). The QSM sequence 400 is an imaging sequence that is executed to acquire a QSM image 410, which will be described later, and more specifically, executes a SWI sequence. The imaging unit 210 obtains a phase image 411 and an absolute value image 412 from a complex image (SWI image) obtained by reconstructing data obtained by the SWI sequence.

  As described above, the QSM image 410 to be described later executes the SWI sequence, obtains the phase map of the tissue from the obtained phase image 411, and obtains the inverse problem. For the SWI sequence, for example, an RF-spoiled steady state free precession (SSFP) sequence or a 3D multi-shot EPI sequence is used. Hereinafter, this SWI sequence is referred to as a QSM sequence 400.

  An example pulse sequence 450 of the 3D RF spoiled SSFP used as the QSM sequence 400 is shown in FIG. 6 (a), and an example pulse sequence 460 of the 3D multi-shot EPI is shown in FIG. 6 (b).

  As shown in FIG. 6A, after applying the RF pulse 451 together with the slice selection gradient magnetic field pulse 452, the 3D RF spoiled SSFP applies the readout gradient magnetic field pulse 454 while changing the gradient magnetic field pulse 453 for applying phase encoding. , Create gradient echo 455, provide rewind pulse 456, and fill multiple lines of k-space with short repetition time (TR). As imaging parameters, for example, FA (flip angle: flip angle) is 18 degrees, TE / TR is 30 ms / 44 ms, integration number is 1, FOV is 256 x 256 mm, slice thickness is 2 mm, measurement matrix is 384 x 160, reconstruction matrix is 512 x 512 Use

  As shown in FIG. 6B, after applying the RF pulse 461 together with the slice selection gradient magnetic field pulse 462, the 3D multi-shot EPI changes the gradient magnetic field pulse 463 for applying phase encoding and reads the readout gradient magnetic field pulse 464. Inverting and repeating, a plurality of gradient echoes 465 are generated, a rewind pulse 466 is given, and a short repetition time is a sequence that fills a plurality of lines of k space. As imaging parameters, for example, FA is 18 degrees, TE / TR is 30 ms / 44 ms, integration number is 1, FOV is 256 × 256 mm, slice thickness is 2 mm, measurement matrix is 384 × 160, and reconstruction matrix is 512 × 512.

[IVIM imaging]
The imaging unit 210 performs IVIM imaging according to the IVIM sequence 500 (step S1103). The IVIM sequence 500 is an imaging sequence executed to acquire an IVIM image 510 to be described later, and here, a diffusion emphasis sequence for acquiring a DWI image, for example, a 2D diffusion emphasis SE-EPI sequence (DW-EPI sequence) Use At this time, the imaging unit 210 changes the b value, performs imaging a plurality of times, and reconstructs the image 511 from each echo signal. The b value to be used is, for example, b = 0, 10, 20, 40, 80, 110, 140, 170, 200, 500, 900, and the like.

  An IVIM image 510 to be described later is generated from the result (DWI image 511) of imaging with a plurality of different b values.

  An example pulse sequence of the DW-EPI sequence 550 used as the IVIM sequence 500 is shown in FIG.

  As shown in the figure, the DW-EPI sequence 550 applies the RF pulses 551 and 552 together with the slice selection gradient magnetic field pulses 553 and 554, and then changes the gradient magnetic field pulse 556 for applying phase encoding to read out the gradient magnetic field pulses. This sequence is a sequence that inverts 557 and repeats to create multiple gradient echos 558 and multiple lines in k-space. In this sequence, one set of diffusion emphasis pulse (MPG pulse) 555 is applied before and after the RF pulse 552. As imaging parameters, for example, TR / TE = 4000/99 ms, b value of MPG pulse = 0, 10, 20, 40, 80, 110, 200, 400, 600, 1000, slice thickness 4 mm, FOV = 297x297 mm, matrix 256x256 A spatial resolution of 1.2 mm × 1.2 mm, parallel imaging factor double speed, partial Fourier 75%, combined use of fat suppression, and imaging time of 3 minutes and 7 seconds are used.

  At this time, the application direction of the MPG pulse 555 is set to three directions of Gs, Gp, and Gf. Imaging is performed on the cross section.

  In the IVIM sequence 500, since there is a flow compensation effect by the MPG pulse 555, the blood vessel signal can be suppressed.

[Other imaging]
Finally, the imaging unit 210 performs imaging for obtaining other diagnostic images, blood vessel imaging (TOF), and the like (step S1104), and ends the process. The obtained images are stored in the storage unit 172 and displayed on the display unit 173.

  As described above, the imaging order does not matter. Moreover, it is not necessary to perform all the imaging as a series of imaging. Alternatively, imaging may be performed in advance, and the obtained reconstructed images may be stored in the storage device 172 and used. The storage device 172 may hold an ASL-PWI image 310, a QSM image 410, and an IVIM image 510 calculated by a sequence acquisition unit described later.

[Sequence image acquisition unit]
Next, a process of generating a sequence image from each reconstructed image by the sequence image acquisition unit 220 will be described. In the present embodiment, as shown in FIG. 3, the sequence image acquisition unit 220 calculates an ASL-PWI image 310 from a reconstructed image obtained by ASL-PWI imaging, and generates a QSM image from a reconstructed image obtained by QSM imaging. Calculate 410. An IVIM image 510 is calculated from the reconstructed image obtained by IVIM imaging.

  The ASL-PWI image 310 is calculated by taking the difference between the label image 312 and the control image 311.

  The QSM image 410 is calculated mainly using the components of the phase image 411. For the calculation of the QSM image 410, for example, a known technique disclosed in, for example, FIG. 6, FIG. 7, and FIG.

The IVIM image 510 fits each image (DWI image) 511 obtained with different b-values as a composite value of two exponential functions for each pixel, and sets the obtained fitting coefficient as a pixel value of the IVIM image 510. Specifically, as shown in FIG. 8, each pixel value (Log signal value) of each obtained image is fitted as a composite value of two exponential functions, and the coefficients of the fitting function (fitting coefficient; DC, D Let ^* , f) be pixel values.

The fitting coefficient obtained as the IVIM image 510 is, for example, a true diffusion coefficient (DC: Diffusion Coefficient), a diffusion coefficient that regards perfusion as diffusion, (D ^* : pseudo-diffusion coefficient), as shown in FIG. Perfusion rate (f).

[Image processing unit]
Next, each process by the image processing unit 230 will be described. The image processing unit of the present embodiment calculates various hemodynamic images from the sequence image. Hereinafter, a hemodynamic image is calculated directly from one type of sequence image, and a second hemodynamic image is calculated from a plurality of hemodynamic images calculated by the first calculation process and the first calculation process. The calculation process of the hemodynamic image by the image processing unit 230 of the present embodiment will be described divided into two of the calculation process.

  Hereinafter, as shown in FIG. 3, among the first calculation processing, the processing for calculating the ASL-CBF image 330 from the ASL-PWI image 310 is referred to as ASL-CBF calculation processing 320 and the QSM image 410 from the QSM image 410. The process to calculate is called QSM-OEF calculation process 420, and the process to calculate the IVIM-CBV image 530 from the IVIM image 510 is called IVIM-CBV calculation process 520. Further, in the second calculation process, a process of calculating the CMRO 2 image 620 from the ASL-CBF image 330 and the QSM-OEF image 430 is a MTR image calculation process from the CMRO 2 calculation process 610 and the ASL-CBF image 330 and the IVIM-CBV image 530. The process of calculating 640 is referred to as MTT calculation process 630.

  First, each process of the first calculation process will be described.

[ASL-CBF calculation processing]
An ASL-CBF calculation process 320 will be described in which an ASL-CBF image 330 is obtained from the ASL-PWI image 310. The ASL-CBF image 330 is obtained by dividing the ASL-PWI image 310 by a separately acquired Proton Density Weighted (PDW) image. The pulse sequence for PDW image acquisition uses a known method. Alternatively, a control image may be diverted by adjusting imaging parameters for PDW images. That is, the image processing unit 230 calculates the CBF (ASL-CBF image 330) from the PWI (ASL-PWI image 310) according to the following equation (1). The PWI (ASL-PWI image 310) is a difference image between the label image 311 and the control image 312.
CBF = α · PWI / PDW (1)
Here, α is a proportionality coefficient, which is an empirically determined value.

[QSM-OEF calculation processing]
The QSM-OEF calculation process 420 is described, which derives a QSM-OEF image 430 from the QSM image 410. As described above, in general, OEF images are calculated from SWI images in different states such as resting and loaded. However, here, the QSM-OEF image 430 is calculated only from the QSM image 410 acquired at rest, using the fact that the magnetic susceptibility of the living tissue changes depending on the amount of iron and the amount of oxygen in the vein.

  As described above, the QSM image 410 is obtained by the method disclosed in Patent Document 4 (method for solving the inverse problem). Then, the image processing unit 230 extracts the intracerebral vein structure by combining the threshold processing and the mask processing in an arbitrary Volume of Interest (VOI) of the QSM image 410. Then, in this VOI, the difference between the magnetic susceptibility of the portion extracted as the vein structure and the magnetic susceptibility of the other portion is determined. Finally, the image processing unit 230 calculates a QSM-OEF image 430 from the data of the difference.

  The method of acquiring the QSM-OEF image 430 only from the QSM image 410 acquired at rest is suitable from the viewpoint of practical application. The reason is that since it is sufficient to perform one measurement, the examination time is short, and no load is placed on the patient, so the load test on the patient can be omitted. Here, the stress test is, for example, drug administration that changes hemodynamics, and is an examination after vasoconstriction by caffeine, hyperventilation, oxygen inhalation, acetazolamide load. .

[IVIM-CBV calculation processing]
An IVIM-CBV calculation process 520 for obtaining an IVIM-CBV image 530 from the IVIM image 510 will be described. As described above, the IVIM image 510 is imaged by using a plurality of different b values in the DWI sequence, and fitting coefficients (log signal values) obtained by fitting each of the obtained images are obtained. For example, the image is a pixel value having a true diffusion coefficient DC, a diffusion coefficient D ^* in which perfusion is regarded as diffusion, and a ratio f of perfusion occupied in the whole.

The image processing unit 230 calculates an IVIM-CBV image 530 according to the following equation (2) using a fitting coefficient which is a pixel value of the IVIM image 510. Formula (2) shows the case where f is used as a representative example.
f = CBV / fw (2)
CB CBV = f x fw
Here, fw is NMR visible water content fraction (NMR observable water content: a value which is set based on past knowledge as a value unique to a tissue), and takes, for example, a value of 0.78.

  Next, each process of the second calculation process will be described using the drawings.

[CMRO2 calculation processing]
Next, a CMRO 2 calculation process 610 for calculating a CMRO 2 image 620 from the ASL-CBF image 330 and the QMS-OEF image 430 will be described using FIG. As described above, the ASL-CBF image 330 is an image representing the blood flow rate of the imaging target site (here, the brain). Also, the QSM-OEF image 430 is an image representing the oxygen uptake rate of the imaging target site (here, the brain). Therefore, the image processing unit 230 basically obtains a CMRO2 image 620 representing brain oxygen consumption by multiplying the two.

  That is, the image processing unit 230 according to the present embodiment multiplies the cerebral blood flow image (ASL-CBF image 330) and the oxygen consumption image (QSM-OEF image 430) to obtain a cerebral oxygen consumption image (CMRO2 image). Calculate 620).

  However, both images are calculated from images obtained by different imaging sequences. For this reason, spatial resolution, slice thickness, etc. differ, and the shape and intensity of the gradient magnetic field pulse differ. In order to perform calculations between both images, the sensitivity distribution on the image derived from the device and the image distortion need to be kept the same between the images. In order to match these, the image processing unit 230 performs various corrections on both images before multiplication.

  The outline of the flow of the CMRO2 calculation process 610 is shown in FIG. As shown in the figure, the image processing unit 230 performs the first hemodynamic image (here, ASL-CBF image 330) and the second hemodynamic image (here, QMS-OEF image 430) prior to the multiplication 616. And at least one of correction processing of mutual alignment processing 611, distortion correction processing 612, Gaussian filter processing 613, mask processing 614, and luminance correction processing 615 is performed. In addition, it is not necessary to perform all of these correction processes.

  Specifically, mutual alignment processing 611, distortion correction processing 612, and Gaussian filter processing 613 are performed to align the ASL-CBF image 330 and the QSM-OEF image 430 using the anatomical standardization method, and then the processing is performed. An ASL-CBF image 331 and a QSM-OEF image 431 are obtained. Thereafter, brain region mask processing 614 is performed using the QSM image 410 obtained by QSM imaging, signal luminance is corrected 615 by brain region average count, and then both images are multiplied 616 to calculate a CMRO2 image 620.

Hereinafter, the ASL-CBF image 330, the QSM-OEF image 430, and the CMRO2 image 620 are respectively described as ASL-CBF (r), QSM-OEF (r) and CMRO 2 (r) as a function of position r. Cross _registration processing 611 is represented as function _{fr1 → r2} , distortion correction processing 612 is represented as function _{dr1 → r2} , Gaussian filter processing 613 as function g, mask processing 614 as function m, and luminance correction processing 615 as function s. The correction process performed prior to the multiplication 616 in the CMRO 2 calculation process 610 is expressed by the following equations (3) to (5). In the functions f and d, the subscript rn → r (n + 1) (n is an integer of 1 or more) represents a process of changing the position on the coordinate from rn to r (n + 1).

First, the ASL-CBF image 331 (ASL-CBF (r3)) and the QSM-OEF image 431 (QSM-OEF (r3)) after mutual registration processing f, distortion correction processing d and Gaussian filter processing g are respectively It is represented by the following formula (3) and formula (4).
ASL-CBF (r3)
= G ( _{dr2 → r3} ( _{fr1 → r2} (ASL-CBF (r1)))) (3)
QMS-OEF (r3)
= G ( _{dr2 r3} ( _{fr1 r2} (QMS-OEF (r1)))) (4)
The order of the correction processes g, d, f may be reversed.

Newly, with r3 as r, mask processing m is performed on each, luminance correction s is performed on the processed ASL-CBF image, and a finally obtained CMRO 2 image 620 (CMRO 2 (r)) has the following formula It is represented by (5).
CMRO 2 (r)
= (M (QMS-OEF (r))) x s (m (ALS-CBF (r))) (5)

  The details of each correction process will be described below.

Mutual alignment process
The mutual _registration processing (function _{fr1 → r2} ) 611 uses the anatomical standard image STD (r1) 621 to select corresponding portions of the brain of the different subject 101 on the standard image STD (r1) 621. It is the processing which makes the same pixel position. The standard image STD (r1) 621 is a standard brain image and is called a template.

  Since the corresponding parts of the brains of different subjects 101 become the same pixel position on the standard brain image by anatomical standardization by mutual alignment processing 611, the brain images of many subjects 101 are pixels on the same soil It can compare each time.

  The function f is a function of nonlinear conversion. For example, in the mutual alignment process 611, "SPM" (Statistical Parametric Mapping) may be used as a known anatomical standardization method (software). In addition, in the case where the ASL-CBF image 330 and the QSM-OEF image 430 are images which do not require alignment, for example, when they are the same slice of the same object 101, the mutual alignment process 611 is not performed. It is also good.

Distortion correction processing
For distortion correction (function d _{r2 → r 3} ) 612, for example, the distortion correction original image DIST (r 1) 622 is used to correct distortion of each image due to the gradient magnetic field. As the distortion correction original image DIST (r1) 622, for example, a standard phantom (for example, an ADNI phantom) whose geometrical position is known can be used.

Here, instead of using the distortion correction original image DIST (r1) 622, design information of the MRI apparatus 100, that is, the spatial magnetic field strength distribution of the gradient magnetic field coil 131 causing distortion is obtained from the equation of biosav In each case, the image distortion produced by this magnetic field distribution may be calculated and inversely corrected. In this case, the distortion correction processing d _{r1 → r 2} 612 means an inverse correction operation itself. This process may not be performed, for example, in the case of imaging under an imaging condition where distortion hardly occurs.

[Gauss filter processing]
The Gaussian filter processing (function g) 613 is a type of so-called smoothing processing. Even in the case of an image with a coarse spatial resolution, by multiplying the Gaussian function by the frequency space, it is possible to express the luminance distribution smoothly, and it is possible to reduce the operation error in the inter-image operation with different voxel sizes. For example, in QSM imaging, imaging is performed in voxel units each having a side of about 25 mm. On the other hand, in ASL imaging, an image with a resolution of about 1 mm can be obtained. As described above, by performing the Gaussian filter processing 613, images having different resolutions and different pixel roughnesses are matched. In addition, as long as it is a smoothing process, another method may be used and this process may be abbreviate | omitted.

[Mask processing]
A mask process (function m) 614 is performed to extract a brain region from the image after each correction. Around the brain, there is a skull, which may adversely affect the subsequent luminance correction process 615, so the skull process is removed by mask processing. An image obtained by extracting a brain region from the QSM image 410 is used as the mask original image MASK (r) 623.

[Brightness correction processing]
The luminance correction process (function s) 615 is a correction related to ASL rescaling. For the signal luminance correction processing 615, for example, an average count in the brain region is used. The average count is the sum of signal values of voxels in a designated region of an MRI image. Since the brightness of the image obtained by the ASL sequence is a relative value, as in the general nuclear medicine examination, for example, the value of a specific normal brain parenchyma such as the cerebellum is subjected to the brightness correction source image SMAP (r ), And normalize the pixel values. On the other hand, since the luminance of the QSM-OEF image 430 is basically an absolute value, no rescaling is necessary.

[MTT calculation processing]
Next, MTT calculation processing 630 for calculating the MTT image 640 from the ASL-CBF image 330 and the IVIM-CBV image 530 will be described with reference to FIG. As described above, the ASL-CBF image 330 is an image representing the blood flow volume of the imaging target site. Also, the IVIM-CBV image 530 is an image representing the blood volume of the imaging target site. Therefore, the image processor 230 basically divides the IVIM-CBV image 530 by the ASL-CBF image 330 to obtain the MTT image 640 representing the average transit time.

  That is, the image processing unit 230 according to the present embodiment divides the cerebral blood volume image (IVIM-CBV image 530) by the cerebral blood flow image (ASL-CBF image 330) to obtain an average transit time image (MTT image 640). Calculate

  As described above, in this embodiment, since the MTT image is obtained from the high-accuracy ASL-CBF image and the high-precision IVIM-CBV image, the accuracy of the MTT image obtained compared to the MTT obtained from the known IVIM alone There is a feature that is high. Further, in the present embodiment, only CBV is calculated from the IVIM image, so DWI imaging protocol using multi-b for IVIM can be set with emphasis on CBV accuracy for the imaging parameter or b value. It has the feature of.

  However, also in the MTT calculation processing 630, the image processing unit 230 performs various correction processing on both images as in the CMRO 2 calculation processing 610. The correction process performed here is basically the same as the process performed on both images in the CMRO 2 calculation process 610.

  That is, in the MTT calculation processing 630, as shown in FIG. 10, first, mutual registration processing 631 using an anatomical standardization method, distortion correction processing 632, and Gaussian filter processing 633 are performed on each of the two images. Obtained ASL-CBF image 331 and IVIM-CBV image 531 after processing. Thereafter, for example, brain region mask processing 634 is performed using the QSM image 410 as the mask original image 623, and luminance correction processing 635 for correcting signal luminance with brain region average count is performed, and then division 636 as described above. And calculate the MTT image 640. The mask image may be an image from which the brain structure can be extracted, and may be a T1W (T1 weighted) image separately captured. Also in the MTT calculation process 630, these correction processes need not necessarily be performed.

  If ASL-CBF image 330, IVIM-CBV image 530, and MTT image 640 are described as ASL-CBF (r), IVIM-CBV (r) and MTT (r) as a function of position r, respectively, MTT calculation The process 630 is expressed by the following equations (6) to (8).

First, the alignment f, the distortion correction d, the ASL-CBF image 331 (ASL-CBF (r3)) and the IVIM-CBV image 531 (IVIM-CBV (r3)) after the Gaussian function processing g are respectively (6) is expressed by equation (7).
ASL-CBF (r3)
= G ( _{dr2 → r3} ( _{fr1 → r2} (ASL-CBF (r1)))) (6)
IVIM-CBV (r3)
= G (dr2 _r3 (fr1 _r2 (IVIM-CBV (r1)))) (7)
The order of the correction processes g, d and f may be reversed.

Newly, with r3 being r, mask processing m is performed on each, luminance correction s is performed on the processed ASL-CBF image and IVIM-CBV image, and an MTT image 640 (MTT (r)) finally obtained Is expressed by the following equation (8). The mask image is converted from r to r3.
MTT (r)
= S ((m (IVIM-CBV (r))) / s (m (ALS-CBF (r))) (8)

  The details of each process are as described in the CMRO2 calculation process 610, so the description will be omitted.

  As described above, the MRI apparatus 100 according to this embodiment measures echo signals from a predetermined area of the subject according to a predetermined imaging sequence that does not use a contrast agent, and obtains a reconstructed image from the obtained echo signals. An imaging unit 210, a sequence image acquisition unit 220 that performs predetermined processing on the reconstructed image to calculate a sequence image, image processing on the sequence image, and hemodynamics of a predetermined region included in the area And an image processing unit 230 for calculating a hemodynamic image to be evaluated, and the imaging unit 210 executes a first imaging sequence and a second imaging sequence different from the first imaging sequence, The sequence image acquisition unit 220 calculates a first sequence image from the reconstructed image obtained by the first imaging sequence, and the second imaging sequence Calculating a second sequence image from the reconstructed image obtained by the image processing unit, the image processing unit 230 generating a first hemodynamic image and the first circulation from the first sequence image and the second sequence image A second hemodynamic image different from the dynamic image is calculated, and the first hemodynamic image and the second hemodynamic image are calculated from the first hemodynamic image and the second hemodynamic image. Calculates a different fourth hemodynamic image.

  The imaging unit 210 further executes a third imaging sequence different from the first imaging sequence and the second imaging sequence, and the sequence image acquiring unit 220 acquires the third imaging sequence according to the third imaging sequence. The image reconstructed from the reconstructed image is subjected to predetermined processing to calculate a third sequence image, and the image processing unit 230 calculates the first hemodynamic image and the first hemodynamic image from the third sequence image. A third hemodynamic image different from the second hemodynamic image is calculated, and one of the first hemodynamic image and the second hemodynamic image and the third hemodynamic image Calculating a fifth hemodynamic image different from any of the first hemodynamic image, the second hemodynamic image, the third hemodynamic image, and the fourth hemodynamic image Good.

  For example, the first imaging sequence is an ASL-PWI sequence 300, the second imaging sequence is a QSM sequence 400, the third imaging sequence is an IVIM sequence 500, the site is a brain, The first hemodynamic image is a cerebral blood flow image 330, the second hemodynamic image is an oxygen uptake rate image 430, and the third hemodynamic image is a cerebral blood volume image 530. The fourth hemodynamic image may be a brain oxygen consumption image 620, and the fifth hemodynamic image may be an average transit time image 640.

  As described above, according to the present embodiment, first, the hemodynamic image (ASL-CBF image 330, QSM-OEF image 430, IVIM-CBV image 530) is calculated using the imaging method of the MRI apparatus that does not use a contrast agent. Do. Then, with regard to the ASL-CBF image 330 and the QSM-OEF image 430, the sensitivity distribution on the device-derived image and the image distortion are corrected to make both images substantially identical, and then the CMRO 2 image 620 is obtained from both images. Calculated indirectly. In addition, for the ASL-CBF image 330 and the IVIM-CBV image 530, the sensitivity distribution and the image distortion on the device-derived image are corrected and made substantially the same between both images, and then the MTT image 640 is indirectly obtained from both images. Calculate to

  That is, in the present embodiment, in the MRI apparatus 100, a plurality of images having different properties (ASL-CBF image 330, QSM-OEF image 430, IVIM-CBV image 530) using different imaging methods without using a contrast agent Other blood flow parameter maps (MTT image 640, CMRO2 image 620, etc.) can be obtained by imaging and post-processing using these. Information on PET is not used to calculate these images.

Therefore, according to the present embodiment, hemodynamics of a predetermined site is evaluated by a low invasive examination method without using radioisotope (for example, ¹⁵ O) or contrast agent for MRI (for example, Gd). It is possible to obtain each image (maximum 5 types of cerebral blood flow information) necessary for Then, it can be presented to the user as appropriate.

  Further, as described above, the MTT image 640 is calculated from the ASL-CBF image 330 and the IVIM-CBV image 530. Therefore, the MTT image 640 can be obtained only from the image at rest. Similarly, in the present embodiment, the QSM-OEF image 430 is calculated only from the QSM image 410 acquired at rest. Therefore, there is no need to acquire a QSM image under load (no need for load testing). For this reason, according to the present embodiment, the load on the subject can be further reduced.

  Also, MPG pulses are used in the ASL-PWI sequence 300 and the IVIM sequence 500. For this reason, since the signal of the blood vessel can be suppressed, it is possible to calculate the MTT image 640 more accurately as compared with the prior art (for example, CE-PWI by MR apparatus or CE-PWI by CT apparatus).

  Furthermore, according to the present embodiment, since acquisition of the hemodynamic image does not have a contrast agent or the like, it is also possible to combine and execute an imaging sequence for obtaining another diagnostic image. Therefore, these can be included for diagnosis.

That is, according to the present embodiment, it is possible to obtain an image in which the information on the blood flow parameter and the structure is combined with only the MRI apparatus 100, and to display the blood flow parameter image in a form suitable for the diagnosis of central nervous disease. Therefore, according to the present embodiment, the blood flow information image displayed in a form suitable for diagnosis of brain diseases, pseudo ¹⁵ O-PET image (virtual ¹⁵ O PET) can be obtained.

  As described above, according to the present embodiment, the MTT image 640 and the CMRO2 image 620 can be acquired non-invasively without using a load test and a contrast agent, and thus widely used in children and healthy people who have not been targeted until now. It can be applied. Specifically, in children, such as moyamoya disease and epilepsy, in healthy people, it can be applied to screening and brain science research. In particular, non-invasive cerebral oxygen metabolism examination in children can not be realized at all by the prior art, so this embodiment is extremely useful clinically.

  In this embodiment, the ASL-PWI sequence 300, the QSM sequence 400, and the IVIM sequence 500 are executed to obtain an ASL-CBF image 330, a QMS-OEF image 430, and an IVIM-CBV image 530, respectively. Although the case where the CMRO 2 image 620 is obtained from 330 and the QMS-OEF image 430 and the MTT image 640 is obtained from the ASL-CBF image 330 and the IVIM-CBV image 530 has been described as an example, the present invention is not limited thereto.

  For example, two imaging sequences may be performed to obtain three hemodynamic images.

  That is, the ASL-PWI sequence 300 and the QSM sequence 400 are executed to obtain the ASL-CBF image 330 and the QMS-OEF image 430, respectively, and obtain the CMRO2 image 620 from the ASL-CBF image 330 and the QMS-OEF image 430. It may be configured as follows.

  Also, the ASL-PWI sequence 300 and the IVIM sequence 500 are executed to obtain an ASL-CBF image 330 and an IVIM-CBV image 530, respectively, and from the ASL-CBF image 330 and the IVIM-CBV image 530, the MTT image 640 is obtained. It may be configured to obtain.

<< Second Embodiment >>
A second embodiment of the present invention will be described. In the first embodiment, each sequence image was acquired by separate and independent imaging. However, in the present embodiment, when calculating a sequence image, an image obtained by another imaging is used.

  That is, in the present embodiment, as the second imaging sequence, a sequence that is performed a plurality of times using a plurality of different predetermined b values is executed, and the imaging unit 210 determines the first imaging sequence The second imaging sequence is performed using any of the plurality of b values, and the second imaging sequence is performed using the remaining b values, and the sequence image acquisition unit 220 performs the second sequence image using the first imaging sequence. Calculation is also performed using the reconstructed image obtained in

  The MRI apparatus of the present embodiment basically has the same configuration as the MRI apparatus 100 of the first embodiment. However, as described above, the imaging process by the imaging unit 210 and the calculation process of the sequence image by the sequence image acquisition unit 220 are different. Hereinafter, the present embodiment will be described focusing on a configuration different from the first embodiment.

  In the present embodiment, as in the first embodiment, a plurality of different imaging methods are taken as imaging by the ASL-PWI sequence 300, the QSM sequence 400, and the IVIM sequence 500, and from reconstructed images obtained by these imaging sequences, The hemodynamic image to be calculated directly is ASL-CBF image 330, QSM-OEF image 430, IVIM-CBV image 530, and the hemodynamic image to be calculated by combining the hemodynamic image calculated directly is CMRO 2 image 620, MTT image The case of 640 will be described as an example.

  In the first embodiment, the ASL-PWI image 310, the QSM image 410, and the IVIM image 510 were respectively acquired by independent imaging. In this embodiment, an image acquired by imaging with the ASL-PWI sequence 300 for acquiring the ASL-PWI image 310 or imaging with the QSM sequence 400 for acquiring the QSM image 410 is used to create the IVIM image 510, , And reduce the number of times of imaging of the IVIM image 510.

  First, an example of the flow of measurement processing and sequence image acquisition processing of the present embodiment when the ASL-PWI image 310 is used to create an IVIM image 510 (first example) will be described using FIG. FIG. 11 is a flowchart of measurement processing of the present embodiment.

  First, the imaging unit 210 performs imaging using the ASL-PWI sequence 300 (step S2101). At this time, in the present embodiment, as described above, an MPG pulse is applied in imaging by the ASL-PWI sequence 300.

  Then, the b value is set to 10, for example. By this imaging, the imaging unit 210 calculates a control image (Control) 311 and a label image (Spin labeled) 312. At this time, in the present embodiment, the imaging unit 210 holds the control image 311 in the storage device 172, for example.

  Next, the imaging unit 210 performs imaging by the QSM sequence 400 (step S2102). Then, the imaging unit 210 calculates a phase image 411 and an absolute value image 412.

  Then, the imaging unit 210 performs imaging using the IVIM sequence 500 (step S2103). Here, imaging is performed multiple times by changing the b value. At this time, imaging is performed only for b values other than the b value (b = 10) used in ASL-PWI imaging. Then, the imaging unit 210 calculates a plurality of images 511 obtained by b values other than the b value used in ASL-PWI imaging.

  Finally, imaging for obtaining other diagnostic images, blood vessel imaging, and the like are performed (step S2104), and the process ends.

  As in the first embodiment, the sequence image acquisition unit 220 of the present embodiment calculates the ASL-PWI image 310 from the control image 311 and the label image 312, and calculates the QSM image 410 from the phase image 411. On the other hand, the IVIM image 510 is calculated using the image 511 obtained by IVIM imaging and the control image 311 obtained by ASL-PWI imaging.

  In the first example, it is preferable that the imaging position, the FOV slice thickness, and the number of matrices be the same for imaging with the ASL-PWI sequence 300 and imaging with the IVIM sequence 500. The reason is that the spatial resolution of the MTT image 640 is determined by the lower spatial resolution when the MTT image 640 is obtained later from both imaging results. In addition, clinical diagnosis is performed by combining the ASL-CBF image 330, the IVIM-CBV image 530, and the MTT image 640.

  When the number of matrices and the FOV of both imagings are different, a known scaling conversion process is added to match the physical position.

  In the present embodiment, the QSM image 410 may be used to create the IVIM image 510. An example of the flow of measurement processing and sequence image acquisition processing in this case (second example) will be described using FIG.

  First, the imaging unit 210 performs imaging using the ASL-PWI sequence 300 (step S2201), and obtains a control image (Control) 311 and a label image (Spin labeled) 312.

  Next, the imaging unit 210 performs imaging using the QSM sequence 400 (step S2202), and calculates a phase image 411 and an absolute value image 412. The phase image 411 and the absolute value image 412 are held, for example, in the storage device 172.

  At this time, the imaging unit 210 applies an MPG pulse in the QSM sequence 400. Then, the b value is set to 10, for example.

  Then, the imaging unit 210 performs imaging by the IVIM sequence 500 (step S2203). Here, imaging is performed multiple times by changing the b value. At this time, imaging is performed only for b values other than the b value (b = 10) used in QSM imaging. Then, the imaging unit 210 calculates a plurality of images 511 obtained by b values other than the b value used in QSM imaging.

  Finally, imaging for obtaining other diagnostic images, blood vessel imaging, and the like are performed (step S2204), and the process ends.

  As in the first embodiment, the sequence image acquisition unit 220 of the present embodiment calculates the ASL-PWI image 310 from the control image 311 and the label image 312, and calculates the QSM image 410 from the phase image 411. On the other hand, the IVIM image 510 is calculated using the image 511 obtained by IVIM imaging and the absolute value image 412 obtained by QSM imaging.

  Also in the second example, it is preferable that the imaging position, the FOV, the slice thickness, and the number of matrices be the same from the viewpoint of position alignment in the imaging by the QSM sequence 400 and the imaging by the IVIM sequence 500. However, for clinical diagnostic requirements, QSM images 410 are generally imaged at high spatial resolution and IVIM images 510 are imaged at relatively low resolution. This is because in the process of obtaining the QSM image 410 from the SWI, it is desirable to have high-definition position information. Therefore, the matrix and the FOV often differ between SWI imaging and ASL-PWI imaging. In such a case, it is used as a low b-value image for IVIM imaging after adding a known scaling transformation process so that the physical locations match.

  As described above, the MRI apparatus of the present embodiment includes the imaging unit 210 similar to that of the first embodiment, the sequence image acquisition unit 220, and the image processing unit 230. Thus, the present embodiment has the same configuration as the first embodiment. Therefore, the same effect as that of the first embodiment can be obtained.

  Furthermore, the second imaging sequence is executed a plurality of times using a plurality of predetermined different b values, and the imaging unit 210 is configured to set the first imaging sequence to any one of the plurality of predetermined b values. And the second imaging sequence is performed using the remaining b values, and the sequence image acquisition unit 220 acquires the second sequence image by the first imaging sequence. The calculation is also performed using the configuration image.

  For example, when the imaging site is the brain and the ASL-PWI sequence 300, the QSM sequence 400, and the IVIM sequence 500 are used as imaging sequences, the imaging unit 210 of this embodiment includes the ASL-PWI sequence 300 and the QSM sequence 400. One of them is executed using any of the predetermined b values, and the IVIM sequence 500 is executed using the remaining b values, and the sequence image acquisition unit 220 further performs an ASL − process on the IVIM image 510. A reconstructed image obtained by executing one of PWI sequence 300 and QSM sequence 400 is also used.

  As described above, according to the present embodiment, one of the ASL-PWI image 310 acquired by ASL-PWI imaging and the QSM image 410 acquired by QSM imaging is used for IVIM-CBV calculation processing. Therefore, according to the present embodiment, in IVIM imaging, only imaging of b-values other than b-value used in ASL-PWI image 310 and QSM 400 acquired in ASL-PWI 300 may be performed, and the entire imaging time is shortened. Do.

  Furthermore, in the case of the first example, in ASL-PWI imaging, the same b value is used in both pulse sequences of the labeling sequence (labeling imaging unit 303; FIG. 5A) and the control sequence (control imaging unit 305). Use. As a result, the blood flow of the image obtained by both sequences is suppressed similarly, and the residual of the blood flow signal in the ASL-PWI image 310 which is a difference image between the control image and the labeling image is reduced. Accuracy is improved.

  Further, in the case of the second example, since the MPG pulse is applied in the QSM sequence, the blood flow of the QSM image 410 is suppressed, phase rotation due to the blood flow in the phase image is eliminated, and the calculation accuracy of the magnetic field map is improved.

  The imaging order does not matter in both the first example and the second example. Moreover, it is not necessary to perform all the imaging as a series of imaging. Each reconstructed image or at least one of the ASL-PWI image 310, the QSM image 410, and the IVIM image 510 is captured in advance and stored in the storage unit 172 for later calculation of the hemodynamic image. It may be configured to use

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described. In the present embodiment, when correcting an image obtained by each imaging, correction is performed using the same correction data for two or more types of images.

  The MRI apparatus of the present embodiment basically has the same configuration as the MRI apparatus 100 of the first embodiment. However, in the present embodiment, correction is performed on an image reconstructed from data obtained by each imaging. Therefore, as shown in FIG. 2B, the control processing unit 170 of the present embodiment further includes a correction unit 240 in addition to the configuration of the control processing unit 170 of the first embodiment. Hereinafter, the present embodiment will be described focusing on a configuration different from the first embodiment.

  Also in the present embodiment, as in the first embodiment, a plurality of different imaging methods are imaging by the ASL-PWI sequence 300, the QSM sequence 400, and the IVIM sequence 500, and calculated directly from reconstructed images obtained by these imaging sequences. The hemodynamic image to be calculated is ASL-CBF image 330, QSM-OEF image 430, IVIM-CBV image 530, and the hemodynamic image calculated by combining the hemodynamic image calculated directly is CMRO2 image 620, MTT image 640 An example case will be described.

[Correction section]
The process of the correction unit 240 of the present embodiment will be described using FIGS. 13 and 14. The correction unit 240 of the present embodiment performs correction of the luminance distribution of the image and correction of the image distortion due to the static magnetic field on the reconstructed image.

  First, the method of correcting the luminance distribution will be described. The correction unit 240 of the present embodiment acquires a sensitivity map 710 from data obtained by a predetermined imaging sequence (sensitivity map acquisition sequence). Then, using the sensitivity map 710, the correction unit 240 corrects 711 the brightness in the image plane of each of the phase image 411, the absolute value image 412, the control image 311, the label image 312, and the image 511 with different b values. . The phase is corrected as necessary for the phase image.

  The sensitivity map acquisition sequence is implemented by the imaging unit 210 prior to each imaging as a prescan after the imaging site is determined. This sensitivity map acquisition sequence uses, for example, a 2D or 3D high-speed GrE sequence. At this time, the sequence parameters are selected so as to eliminate the T1 and T2 and contrast of the subject as much as possible. The number of matrices in the plane is about 32 or 64.

  The sensitivity map 710 obtained by the sensitivity map acquisition sequence is a map mainly having the in-plane sensitivity distribution of the transmitting coil 151 and the in-plane sensitivity distribution of the receiving coil 161. The correction unit 240 of the present embodiment corrects the luminance distribution of each image using this sensitivity map 710. Thereby, the influence of the sensitivity of the MRI apparatus 100 (transmission coil and reception coil) can be reduced or eliminated from the final image.

  Next, correction of image distortion due to static magnetic field will be described. The correction unit 240 of the present embodiment generates a magnetic field map 720 from the phase image 411 obtained by QSM imaging. Then, using the magnetic field map 720, the correction unit 240 corrects 721 the image distortion due to each of the control image 311, the label image 312, the image 511 with different b-values, and the respective magnetic fields.

  This correction extracts the static magnetic field components up to the first order term, second order term and third order term when the magnetic field distribution in the plane is polynomially expanded from the magnetic field map 720, estimates distortion of the image, and corrects the distortion. It is a process. For example, in the brain, the lower part of the brain, the paranasal sinuses, and the fundus part are adjacent to hollow parts in the body, so local magnetic field distortion occurs in these parts and image quality is greatly distorted. Especially in imaging using an EPI sequence, the image distortion is remarkable. The correction unit 240 of the present embodiment corrects such local distortion using the magnetic field map 720.

  Here, the flow of the imaging process by the imaging unit 210 and the correction process by the correction unit 240 according to the present embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 is a processing flow for explaining the in-plane luminance correction 711 by the sensitivity map 710, and FIG. 14 is a processing flow for explaining the static magnetic field image distortion correction 721 by the magnetic field map 720. The processing of each step is the same and will be described using both figures.

  The imaging unit 210 executes a sensitivity map acquisition sequence (step S3101). Then, the correction unit 240 acquires the sensitivity map 710.

  Next, the imaging unit 210 performs imaging using the QSM sequence 400 (step S3102), and acquires a phase image 411 and an absolute value image 412. The correction unit 240 corrects 711 the in-plane luminance of these images using the sensitivity map 710. The phase is corrected as necessary for the phase image. Furthermore, the correction unit 240 generates a magnetic field map 720 from the phase image 411.

  Next, the imaging unit 210 performs imaging using the ASL-PWI sequence 300 (step S3103), and acquires the control image 311 and the label image 312. The correction unit 240 corrects 711 the in-plane luminance of the control image 311 and the label image 312 using the sensitivity map 710. The correction unit 240 also corrects 721 the image distortion of these images due to the static magnetic field, using the magnetic field map 720.

  Then, the imaging unit 210 changes the b value, performs imaging with the IVIM sequence 500 multiple times (step S3104), and obtains a plurality of images 511 for each b value. The correction unit 240 corrects 711 the in-plane luminance of each image 511 using the sensitivity map 710. Further, the correction unit 240 corrects 721 the image distortion due to the static magnetic field of each image 511 using the magnetic field map 720.

  Finally, imaging for obtaining other diagnostic images, blood vessel imaging, and the like are performed (step S3105), and the process ends.

  The order of imaging does not matter. Also, each correction does not have to be performed each time an image is acquired. The correction timing does not matter as long as the hemodynamic image is calculated. For example, correction may be performed collectively after all imaging has been completed.

  Moreover, it is not necessary to perform all the imaging as a series of imaging. At least one image of each reconstructed image, ASL-PWI image 310, QSM image 410, and IVIM image 510 is captured in advance by the same subject 101 and the same MRI apparatus 100, held in the storage device 172, and thereafter It may be configured to be used to calculate the hemodynamic image.

  As described above, the MRI apparatus of the present embodiment includes the imaging unit 210 similar to that of the first embodiment, the sequence image acquisition unit 220, and the image processing unit 230. Thus, the present embodiment has the same configuration as the first embodiment. Therefore, the same effect as that of the first embodiment can be obtained.

  Further, the MRI apparatus 100 of the present embodiment further includes a correction unit 240 that performs correction processing on the reconstructed image, and the imaging unit 210 further executes a sensitivity map acquisition sequence for generating the sensitivity map 710. The correction unit 240 generates the sensitivity map 710 from the execution result of the sensitivity map acquisition sequence, and corrects the luminance of the reconstructed image using the sensitivity map 710.

  Furthermore, when the imaging site is the brain and the ASL-PWI sequence 300, the QSM sequence 400 and the IVIM sequence 500 are used as the imaging sequence, the correction unit 240 of this embodiment determines the phase image obtained by the QSM sequence 400. A magnetic field map 720 is generated from 411, and the magnetic field map 720 is used to reconstruct an image (control image 311, label image 312) reconstructed from the execution result of the ASL-PWI sequence and an execution result of the IVIM sequence. The image distortion due to the static magnetic field of at least one of the images (image group 511 obtained with different b-values) may be corrected.

  As described above, in the present embodiment, since the sensitivity distribution for each imaging and the magnetic field distortion can be corrected by the same correction data, high correction accuracy can be obtained.

  The present embodiment may be combined with the second embodiment.

  Further, the sensitivity map of the present embodiment can be used, for example, as the luminance correction source image SMAP (r) of the first embodiment and the second embodiment. That is, in the luminance correction processing 615, the luminance distribution in the image plane may be corrected using the sensitivity map of the present embodiment.

  In addition, the method of each said embodiment can be used instead of SPECT (Single Photo Emission CT).

  Acetazolamide is used for SPECT load test. Acetazolamide has cerebral vasodilator activity, and in normal brain, regional cerebral blood flow is increased, while brain metabolism, blood pressure, respiration, pulse, etc. are hardly affected. Therefore, it is used to evaluate cerebrovascular reactivity (brain circulation reserve).

  The cerebral circulation reserve is evaluated, for example, when there is a lesion such as severe stenosis or occlusion in the cerebral main artery. In such a case, the blood flow of the brain on the normal side is increased due to acetazolamide loading, and the stenosis side is not increased. Information on the treatment plan can be obtained by the presence or absence of such blood flow elevation.

  Although it is acetazolamide load SPECT widely used in clinical practice, the acetazolamide reactivity of SPECT has a disadvantage that the correlation with CBV and OEF is low and the invasiveness is large.

  On the other hand, according to the method of the present embodiment, similar information can be obtained by measurement of non-contrast MRI. That is, according to the present embodiment, there is an advantage that the blood vessel reserve and metabolic reserve can be accurately evaluated noninvasively.

  In each of the above embodiments, the image reconstruction function of the imaging unit, the sequence image acquisition unit, and the image processing unit have been described as being included in the MRI apparatus 100, but the present invention is not limited to this. For example, at least one of these functions may be built on an information processing apparatus that can transmit and receive data with the MRI apparatus 100 and is independent of the MRI apparatus 100.

  100: MRI apparatus, 101: object, 120: static magnetic field generation unit, 130: gradient magnetic field generation unit, 131: gradient magnetic field coil, 132: gradient magnetic field power supply, 140: sequencer, 150: transmission unit, 151: transmission coil, 152: high frequency oscillator, 153: modulator, 154: high frequency amplifier, 160: receiver, 161: receiving coil, 162: signal amplifier, 163: quadrature detector, 164: D converter, 170: control processor, 171 : CPU, 172: storage device, 173: display device, 174: input device, 200: imaging process, 210: imaging unit, 220: sequence image acquisition unit, 230: image processing unit, 240: correction unit, 300: ASL- PWI sequence, 301: label pulse, 302: image acquisition sequence, 303: labeling imaging unit, 304: control pulse 305: control imaging unit 310: ASL-PWI image 311: control image 312: label image 320: ASL-CBF calculation processing 330: ASL-CBF image 331: ASL-CBF image 350: EPI sequence , 351: RF pulse, 352: slice selection gradient magnetic field pulse, 353: phase encoding gradient magnetic field pulse, 354: frequency encoding gradient magnetic field pulse, 355: gradient echo, 400: QSM sequence, 410: QSM image, 411: phase image, 412: absolute value image, 420: QSM-OEF calculation processing, 430: QSM-OEF image, 431: QSM-OEF image, 450: pulse sequence example, 460: pulse sequence example, 500: IVIM sequence, 510: IVIM image, 511 Image 520: IVIM-CBV calculation process 530: IVIM-CBV image 531: IVIM-CBV image 550: EPI sequence 555: MPG pulse 610: CMRO2 calculation process 611: relative alignment process 612: distortion Correction processing 613: Gaussian filter processing 614: mask processing 615: luminance correction processing 616: multiplication 620: CMRO2 image 621: anatomical standard image 622: original image for distortion correction 623: original mask image , 624: luminance correction original image, 630: MTT calculation processing, 631: mutual alignment processing, 632: distortion correction processing, 633: Gaussian filter processing, 634: mask processing, 635: luminance correction processing, 636: division, 640: MTT image 710: sensitivity map 711: in-plane brightness correction 720: magnetic field Map, 721: Static magnetic field image distortion correction

Claims (13)

An imaging unit that measures an echo signal from a predetermined region of a subject according to a predetermined imaging sequence that does not use a contrast agent, and obtains a reconstructed image from the obtained echo signal;
A sequence image acquisition unit that performs predetermined processing on the reconstructed image and calculates a sequence image;
An image processing unit that performs image processing on the sequence image to calculate a hemodynamic image for evaluating hemodynamics of a predetermined region included in the area;
The imaging unit includes a first imaging sequence, a second imaging sequence different from the first imaging sequence, and a third imaging sequence different from the first imaging sequence and the second imaging sequence Run
The sequence image acquisition unit calculates a first sequence image from the reconstructed image obtained by the first imaging sequence, and calculates a second sequence image from the reconstructed image obtained by the second imaging sequence. , subjected to predetermined processing in the reconstructed image from the reconstructed image obtained by the third imaging sequence, calculating a third sequence image,
The image processing unit calculates a first hemodynamic image and a second hemodynamic image different from the first hemodynamic image from the first sequence image and the second sequence image, respectively. A third hemodynamic image different from the first hemodynamic image and the second hemodynamic image is calculated from the third sequence image, and the first hemodynamic image and the second hemodynamic From the image, a fourth hemodynamic image different from the first hemodynamic image and the second hemodynamic image is calculated, and either one of the first hemodynamic image and the second hemodynamic image A fifth blood flow different from any of the first blood flow image, the second blood flow image, the third blood flow image, and the fourth blood flow image from the third blood flow image and the third blood flow image; Action Magnetic resonance imaging apparatus and calculates an image. The magnetic resonance imaging apparatus according to claim 1 ,
The first imaging sequence is an ASL-PWI sequence,
The second imaging sequence is an imaging sequence for acquiring QSM,
The third imaging sequence is an imaging sequence for acquiring IVIM,
The site is the brain,
The first hemodynamic image is a cerebral blood flow image.
The second hemodynamic image is an oxygen uptake rate image,
The third hemodynamic image is a cerebral blood volume image,
The fourth hemodynamic image is a cerebral oxygen consumption image.
The magnetic resonance imaging apparatus, wherein the fifth hemodynamic image is an average transit time image. The magnetic resonance imaging apparatus according to claim 2 ,
The image processing apparatus further comprises a correction unit that performs correction processing on the reconstructed image,
The correction unit generates a magnetic field map from a reconstructed image obtained by the QSM sequence, and using the magnetic field map, at least at least a reconstructed image obtained by the ASL-PWI sequence and a reconstructed image obtained by an IVIM sequence. A magnetic resonance imaging apparatus characterized by correcting image distortion due to one of static magnetic fields. The magnetic resonance imaging apparatus according to claim 1 ,
The image processing apparatus further comprises a correction unit that performs correction processing on the reconstructed image,
The imaging unit further executes a sensitivity map acquisition sequence for generating a sensitivity map,
The magnetic resonance imaging apparatus, wherein the correction unit generates the sensitivity map from the execution result of the sensitivity map acquisition sequence, and corrects the luminance of the reconstructed image using the sensitivity map. An imaging unit that measures an echo signal from a predetermined region of a subject according to a predetermined imaging sequence that does not use a contrast agent, and obtains a reconstructed image from the obtained echo signal;
A sequence image acquisition unit that performs predetermined processing on the reconstructed image and calculates a sequence image;
An image processing unit that performs image processing on the sequence image to calculate a hemodynamic image for evaluating hemodynamics of a predetermined region included in the area;
The imaging unit executes a first imaging sequence and a second imaging sequence different from the first imaging sequence.
The sequence image acquisition unit calculates a first sequence image from the reconstructed image obtained by the first imaging sequence, and calculates a second sequence image from the reconstructed image obtained by the second imaging sequence. ,
The image processing unit calculates a first hemodynamic image and a second hemodynamic image different from the first hemodynamic image from the first sequence image and the second sequence image, respectively. A magnetic resonance imaging apparatus that calculates a fourth hemodynamic image different from the first hemodynamic image and the second hemodynamic image from the first hemodynamic image and the second hemodynamic image. ,
The first imaging sequence is an ASL-PWI sequence,
The second imaging sequence is an imaging sequence for acquiring IVIM (IntraVoxel Incoherent Motion),
The site is the brain,
The first hemodynamic image is a cerebral blood flow image.
The second hemodynamic image is a cerebral blood volume image,
The magnetic resonance imaging apparatus, wherein the fourth hemodynamic image is an average transit time image. The magnetic resonance imaging apparatus according to claim 5 ,
The magnetic resonance imaging apparatus, wherein the image processing unit calculates the average transit time image by dividing the cerebral blood volume image by the cerebral blood flow image. The magnetic resonance imaging apparatus according to claim 5 ,
The first imaging sequence and the second imaging sequence are sequences for applying Motion Probing Gradient (MPG) pulses, respectively.
The second imaging sequence is performed a plurality of times using a plurality of predetermined different b values,
The imaging unit executes the first imaging sequence using any of the plurality of predetermined b values, and executes the second imaging sequence using the remaining b values.
The magnetic resonance imaging apparatus, wherein the sequence image acquisition unit calculates the second sequence image also using a reconstructed image obtained by the first imaging sequence. The magnetic resonance imaging apparatus according to claim 7 ,
A magnetic resonance imaging apparatus characterized in that the first imaging sequence is executed with the second imaging sequence being made to coincide with at least one of an imaging position, an FOV, a slice thickness, and a number of matrices. An imaging unit that measures an echo signal from a predetermined region of a subject according to a predetermined imaging sequence that does not use a contrast agent, and obtains a reconstructed image from the obtained echo signal;
A sequence image acquisition unit that performs predetermined processing on the reconstructed image and calculates a sequence image;
An image processing unit that performs image processing on the sequence image to calculate a hemodynamic image for evaluating hemodynamics of a predetermined region included in the area;
The imaging unit executes a first imaging sequence and a second imaging sequence different from the first imaging sequence.
The sequence image acquisition unit calculates a first sequence image from the reconstructed image obtained by the first imaging sequence, and calculates a second sequence image from the reconstructed image obtained by the second imaging sequence. ,
The image processing unit calculates a first hemodynamic image and a second hemodynamic image different from the first hemodynamic image from the first sequence image and the second sequence image, respectively. A magnetic resonance imaging apparatus that calculates a fourth hemodynamic image different from the first hemodynamic image and the second hemodynamic image from the first hemodynamic image and the second hemodynamic image. ,
The image processing unit performs mutual registration processing, distortion correction processing, and Gaussian filtering on at least one of the first hemodynamic image and the second hemodynamic image prior to calculation of the fourth hemodynamic image. A magnetic resonance imaging apparatus characterized by performing at least one of processing, mask processing, and luminance correction processing. The magnetic resonance imaging apparatus according to claim 9 ,
The first imaging sequence is an ASL-PWI (Arterial Spin Labeling-Perfusion Weighted Imaging) sequence,
The second imaging sequence is an imaging sequence for acquiring a quantitative susceptibility map (QSM),
The site is the brain,
The first hemodynamic image is a cerebral blood flow image.
The second hemodynamic image is an oxygen uptake rate image,
The magnetic resonance imaging apparatus, wherein the fourth hemodynamic image is a cerebral oxygen consumption image. The magnetic resonance imaging apparatus according to claim 10 ,
The magnetic resonance imaging apparatus, wherein the image processing unit calculates the cerebral oxygen consumption image by multiplying the cerebral blood flow image and the oxygen uptake rate image. Calculating a first hemodynamic image for evaluating hemodynamics of the region from the first reconstructed image of the predetermined region of the subject obtained according to the first imaging sequence using no contrast agent;
Different from the first hemodynamic image from the second reconstructed image of the site obtained according to the second imaging sequence different from the first imaging sequence and using no contrast agent, and Calculating a second hemodynamic image to assess the hemodynamics of the site;
The first hemodynamics from a third reconstructed image of the site obtained according to a third imaging sequence different from the first imaging sequence and the second imaging sequence and using no contrast agent Calculating a third hemodynamic image, different from the image and the second hemodynamic image, and evaluating the hemodynamics of the site,
Unlike the first hemodynamic image and the second hemodynamic image, the hemodynamics of the site are evaluated from the first hemodynamic image and the second hemodynamic image, and A fourth hemodynamic image for evaluating the hemodynamics of the region is calculated, and either one of the first hemodynamic image and the second hemodynamic image and the third hemodynamic image, the region of the region Hemodynamics is evaluated, which is different from any of the first hemodynamic image, the second hemodynamic image, the third hemodynamic image, and the fourth hemodynamic image, and the hemodynamics of the site An image creation method characterized by further calculating a fifth hemodynamic image to be evaluated.   The image creation method according to claim 12,
  The first imaging sequence is an ASL-PWI sequence,
  The second imaging sequence is an imaging sequence for acquiring QSM,
  The third imaging sequence is an imaging sequence for acquiring IVIM,
  The site is the brain,
  The first hemodynamic image is a cerebral blood flow image.
  The second hemodynamic image is an oxygen uptake rate image,
  The third hemodynamic image is a cerebral blood volume image,
  The fourth hemodynamic image is a cerebral oxygen consumption image.
  The fifth hemodynamic image is an average transit time image
A method of creating an image characterized by

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