JPH05309078A - Magnetic resonance imaging device - Google Patents

Abstract

PURPOSE:To prevent an artifact by forming a pulse sequence by a collection sequence part in a specific area and a pre-saturation sequence part, and allowing the collection sequence part to contain an inclined magnetic field for preventing generation of the artifact caused by a motion. CONSTITUTION:A pulse sequence is constituted of a pre-saturation sequence part 24a and a spin echo pulse sequence part 24b being a collection sequence. The pre-saturation sequence part 24a suppresses a signal from a cerebrospinal fluid, and also, increases a signal from other tissue. Also, the spin echo pulse sequence part 24b contains an inclined magnetic field MPG for preventing generation of an artifact caused by a motion in a prescribed area. In such a way, plural pieces (n) of images are photographed, and the MPG of every image is varied. As a result, by an operation of both the sequences, a magnetized component of a moving area is suppressed, and ghost is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention utilizes morphological information such as a slice image of a subject (living body) and the like by utilizing a magnetic resonance (MR) phenomenon. The present invention relates to a magnetic resonance imaging apparatus (MRI apparatus) that obtains morphological information such as spectroscopy.

(Prior Art) A magnetic resonance phenomenon is a phenomenon in which an atomic nucleus with a non-zero spin and magnetic moment placed in a static magnetic field resonantly absorbs and emits only an electromagnetic wave of a specific frequency. Resonance occurs at an angular frequency ω ₀ (ω ₀ = 2πν ₀ , ν ₀ ; Larmor frequency) shown in the following formula.

ω ₀ = γH ₀ Here, γ is the gyromagnetic ratio p peculiar to the type of atomic nucleus, and H ₀ is the static magnetic field strength.

A device for performing a biomedical diagnosis using the above principle performs signal processing on the electromagnetic wave of the same frequency as that induced after the above-mentioned resonance absorption to obtain the nuclear density, the longitudinal relaxation time T ₁ , and the transverse relaxation time T ₂ , Non-invasively obtains diagnostic information that reflects information such as flow and chemical shift, such as slice images of the subject.

 Moreover, the collection of diagnostic information by magnetic resonance can excite all parts of the subject placed in a static magnetic field and collect signals, but there are restrictions on the device configuration and clinical imaging images. Upon request, an actual device is designed to perform excitation and signal acquisition for a specific site.

 In this case, the specific region to be imaged is generally a slice region having a certain thickness, and an echo signal from this slice region or a magnetic resonance signal (MR signal) of the FID signal is detected many times. The data is collected by executing the data encoding process, and the data group is subjected to image reconstruction processing by, for example, the two-dimensional Fourier transform method to generate the image of the specific slice region.

 On the other hand, recently, it has been proposed to use this type of MRI apparatus to image Diffusion / Perfusion quantitatively or qualitatively. For example, Radiology 168 497-505: Le. Bihan (1988).

Here, Diffusion refers to diffusion, which is the movement (Brownian motion) of water molecules in living tissue, and Perfusion refers to, for example, perfusion, which is the flow of blood in a capillary tube.

 Then, methods for performing Diffusion / Perfusion imaging using the MRI apparatus include IVCM (Intra Voxel Coherent Motion) imaging and IVIM (Intra Voxel Incoherent Motion) imaging. IVCM imaging is to image the movement of protons in one direction on average in voxels, and IVIM imaging is to image the movement of protons in random directions in voxels.

 In the Diffusion / Perfusion imaging by the above-mentioned IVIM imaging or the like, in order to sensitively capture the movement of minute water molecules, conventionally, a large gradient magnetic field pulse was used for measurement. In this case, information on water diffusion (Diffusion) and tissue blood flow (Perfusion) is useful information to be measured, and information based on CSF (cerebrospinal fluid) and body movement is unnecessary information. However, in order to emphasize the phase shift shift due to motion with a large gradient magnetic field pulse, ghosts in the encoding direction due to pulsation due to CSF occurred especially when the brain, spinal cord, etc. were subjected to imaging examination. This is called a motion artifact.

 Because of this motion artifact, the electrocardiographic synchronization (ECG) method has been conventionally used. There is also an attempt to suppress the occurrence of ghosts by using the echo planar method, which is an ultra-high-speed imaging method capable of imaging in the order of tens of msec.

(Problems to be Solved by the Invention) However, in the ECG method, it is necessary to attach a large number of electrodes to the subject for gating, which is a problem. In the case of arrhythmia and heart beat interval is unstable subject, variation in spacing of the pulse sequence of the MRI device (T _R) is Ji live, which therefore had to new ghost occurs. Furthermore, in the area where the CSF is large, even if the ECG method is performed, the reduction of artifacts is not sufficient. Further, in the method using the echo planar method, the apparatus itself has not been sufficiently established, and even the ECG method has a problem in any of the echo planar methods.

 Therefore, an object of the present invention is to provide a magnetic resonance imaging apparatus capable of simply executing favorable Diffusion / Perfusion imaging instead of the ECG method.

 [Structure of the Invention] (Means for Solving the Problems) The present invention has a structure in which the following means are provided in order to solve the above problems and achieve the object.

That is, the invention according to claim 1 is a magnetic resonance imaging apparatus having a means for executing a pulse sequence for quantifying diffusion of water in a biological tissue or blood flow in a tissue, wherein the pulse sequence is a subject A collection sequence section that excites a specific region of the magnetic resonance by magnetic resonance and collects magnetic resonance signals from the excitation site, and is executed prior to the collection sequence section and has an overlap with the excitation site. It is characterized in that it comprises a presaturation sequence section that saturates the magnetization component of the region, and that the acquisition sequence section includes a gradient magnetic field for preventing the occurrence of artifacts due to movement.

According to a second aspect of the present invention, in a magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying diffusion of water in a biological tissue or blood flow in a tissue, the pulse sequence is for identifying a subject. A collection sequence section that excites the region by magnetic resonance and collects magnetic resonance signals from the excitation site, and a region that overlaps with the excitation site that is executed before the collection sequence section. It consists of a presaturation sequence part that saturates the magnetization component, the acquisition sequence part contains a gradient magnetic field to prevent the occurrence of artifacts due to movement, and the presaturation sequence part contains signals from cerebrospinal fluid. Is satisfied and the conditions for increasing the signal from other tissues are satisfied.

 The invention according to claim 3 is a magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying diffusion of water in a biological tissue or blood flow in a tissue, wherein the pulse sequence is for identifying a subject. A collection sequence section that excites the region by magnetic resonance and collects magnetic resonance signals from the excitation site, and a region that overlaps with the excitation site that is executed before the collection sequence section. It is characterized in that it comprises an inversion sequence section for inverting the magnetization component by 180 °, and the acquisition sequence section contains a gradient magnetic field for preventing the occurrence of artifacts due to movement.

 The invention according to claim 4 is the magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying the diffusion of water in a biological tissue or the blood flow in a tissue, wherein the pulse sequence is for identifying a subject. A collection sequence section that excites the region by magnetic resonance and collects magnetic resonance signals from the excitation site, and a region that overlaps with the excitation site that is executed before the collection sequence section. An inversion sequence part for inverting the magnetization component by 180 °, the acquisition sequence part includes a gradient magnetic field for preventing the occurrence of motion artifacts, and the inversion sequence part is a signal from cerebrospinal fluid. It is characterized by satisfying the conditions of suppressing the signal and increasing the signal from other tissues.

 (Operation) According to the invention of claim 1, the (longitudinal) magnetization component of the region that moves by the execution of the presaturation sequence part is suppressed, and the occurrence of motion artifacts in the acquisition sequence part is prevented. Since the gradient magnetic field is included, the signal collected by the execution of the acquisition sequence section has few ghosts. Therefore, the Diffusion / Perfusion imaging image generated by the data group obtained by executing the sequence many times is of good quality without any motion artifact.

Moreover, since the above-mentioned effects are achieved purely by devising the sequence, there is no problem in the ECG method and the ecoplanar method as in the past.

 According to the invention of claim 2, in addition to the action of the invention of claim 1, the presaturation sequence part satisfies the condition of suppressing signals from cerebrospinal fluid and increasing signals from other tissues. Therefore, when the brain, spinal cord, or the like is used as an imaging examination, the effect of CSF, which can be particularly remarkable, is suppressed. Therefore, Diffusion / Perfusion imaging with reduced motion artifacts and suppressed CSF effects is realized.

 According to the invention of claim 3, the execution of the inversion sequence section suppresses the influence of CSF that can be particularly remarkable when the brain, spinal cord, or the like is subjected to an erasing test. The effect of CSF will be suppressed in the collected signal. Therefore, the Diffusion / Perfusion imaging image generated by the data group obtained by executing the sequence many times is of high quality in which the influence of CSF is suppressed. Moreover, since the above-mentioned effect is achieved purely by devising the sequence, there is no problem in the ECG method and the echo planar method as in the conventional case.

 According to the invention of claim 4, in addition to the effect of the invention of claim 3, since the acquisition sequence part includes a gradient magnetic field for preventing the occurrence of artifacts due to motion, the acquisition is performed by executing the sequence. Diffusion / perfusion imaging in which the effect of CSF is suppressed and motion artifacts are reduced is realized, since the generated signal has few ghosts.

 (Embodiment) An embodiment of the magnetic resonance imaging apparatus according to the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing the overall configuration of the magnetic resonance imager device of this embodiment, FIG. 2 is a diagram showing an imaging region for performing Diffusion / Perfusion imaging by the device, and FIG. 3 is a diagram showing the Diffusion / Perfusion device by the device. It is a figure which shows one encoding part of the PAST-SE-IVIM pulse sequence which is the 1st example of the pulse sequence which can perform imaging.

 As shown in FIG. 1, a magnet assembly MA capable of accommodating a subject P therein is provided with a static magnetic field coil (a static magnetic field correction shim coil is added by a normal conducting or superconducting method). 10), a gradient magnetic field generating coil 12 of X, Y, and Z axes for generating a gradient magnetic field for giving position information of the position where the magnetic resonance signal is induced, and a high-frequency magnetic field for excitation ( An all-reliable probe 14 consisting of, for example, a transmission coil and a reception coil, which is a transmission / reception system for transmitting an RF pulse) and detecting an induced magnetic resonance signal (echo signal), and a small probe 16 for local high-sensitivity reception are provided. Is configured.

 Further, a transmitter 18 for controlling the transmission of the RF pulse, a receiver 20 for controlling the reception of the induced MR signal, an X-axis for controlling the excitation of the X, Y, Z axis gradient magnetic field generating coil 12, respectively. A Y-axis and Z-axis gradient magnetic field power source 20, a sequencer 22 for executing a pulse sequence shown in FIG. 3, and a Diffusion / Perfusion imaging sequence generating means 24, and controlling them, and processing a detection signal. And a computer system 26 for displaying it and a monitor 28.

 Here, the Diffusion / Perfusion imaging sequence generation means 24 can be basically regarded as a part of a sequencer, but the Diffusion / Perfusion imaging sequence generation means 24 includes a presaturation sequence generation unit 24a, It is composed of a spin echo pulse sequence generation unit 24b and a total pulse sequence generation unit 24c.

 Here, the site shown in FIG. 2 is considered as a Diffusion / Perfusion imaging site.

That is, it is considered that the head axial section HA is excited. The subject P is placed in a static magnetic field, in which the head PH is placed at the center of the magnetic field, and the small probe 16 is placed on the head PH. As a result, a static magnetic field, a gradient magnetic field, and an RF pulse can be applied to the head PH, and an echo signal induced from the head PH can be collected. Then, the transmitter 5 is driven by operating the sequencer 22, and an RF pulse (arbitrary flip angle pulse, 90 ° pulse, 180 ° pulse) is generated from the transmitting coil of the probe 14, and the gradient magnetic field electric field is generated. The source 20 is driven to generate gradient magnetic fields G _X , G _Y , and G _Z from the gradient magnetic field generating coil 12 for slicing, phase encoding, and reading, and a small probe 16 outputs a signal induced from a specific part of the head. It will be possible to collect with the receiving coil of.

Then, the sequence is repeated a predetermined number of times to obtain a data group, a reconstructed image is generated by the computer system, and displayed on the monitor 28.

 FIG. 3 is a diagram showing one encoded portion of the PAST-SE-IVIM pulse sequence executed by the apparatus of this embodiment, which is composed of a presaturation sequence part and a spin echo pulse sequence part as an acquisition sequence. There is.

 The presaturation sequence part is executed prior to the spin echo pulse sequence part, and is a region that overlaps with the axial section HA described later, and is a spoiler for the longitudinal magnetization component of one hatched region in FIG. The signal from CSF (cerebrospinal fluid) is suppressed by selecting the flip angle α and setting the dilator time τd from α ° pulse to 90 ° pulse, which is saturated by the pulse SP. It increases the signal from other tissues.

 The spin echo pulse sequence section is to excite the axial section HA of the head PH 1 by magnetic resonance to collect magnetic resonance signals from the excitation site, and to prevent the occurrence of artifacts due to movement in the area. It is a 90 ° -180 ° pulse sequence including a gradient magnetic field MPG (Motion Probing Gradient).

Note that the saturation region is determined by the presaturation sequence unit by specifying the ROI while observing the monitor 28 on the image of the axial cross-section HA taken in advance, for example, for position determination, and thereby determining the RF pulse based on the ROI. (Α ° pulse) and the strength of the Z-axis gradient magnetic field (slice gradient magnetic field) are calculated manually or automatically. T _E is the echo time and T _R is the repetition interval of the pulse sequence.

 Although the above process is for one encoding, in the present embodiment, it is assumed that a plurality of n images are photographed and the number of data (the number of encodings) required for one image is m. At this time, the MPG for each image is changed. In this case, the area of MPG is the same for each image, and the intensity G, the application time d, and the interval I are changed.

That is, MPG ₁ in the _first image is G ₁ , d ₁ , I ₁ , MPG ₂ in the first image is G ₂ , d ₂ , I ₂ , ..., In the nth image. MPG _n is G _n , d _n , I _n .

In addition, the encoding gradient magnetic field G _E is naturally changed for each encoding.

 As described above, according to the present embodiment, the (longitudinal) magnetization component of the moving region is suppressed by the execution of the presaturation sequence part, and the spin echo pulse sequence part is provided for preventing the occurrence of the artifact due to the motion. Since the spoiler pulse SP is included, the signal collected by the execution of the spin echo pulse sequence section has few ghosts in the encoat direction. Therefore, the Diffusion / Perfusion imaging image generated from the data group obtained by executing the sequence multiple times is of good quality without motion artifacts. Moreover, since the above-mentioned effect is achieved purely by devising the sequence, there is no problem in the ECG method and the echo planar method as in the conventional case.

 In addition, the presaturation sequence part suppresses the signal from the cerebrospinal fluid and preferably satisfies the condition that it is zero and increases the signal from other tissues, preferably maximizing the signal. The effect of CSF, which can occur remarkably, is suppressed when is set as an imaging inspection target. Therefore, Diffusion / Perfusion imaging in which motion artifacts are reduced and the influence of CSF is suppressed is realized.

 Furthermore, since n Diffusion / Perfusion imaging images of the same cross-section with different motion artifacts, that is, only different MPGs, can be obtained, the information parameters can be calculated by comparing and referring to Diffusion or Perfusion. ..

Next, the generation of the PAST-SE-IVIM pulse sequence will be described with reference to FIGS. 4 and 5. That is, as shown in FIG. 4, one or more presaturation sequences PSAT are stored in advance in the presaturation sequence generation unit 24a, and the spin echo pulse sequence generation unit 24b stores n encoded data. The spin echo pulse sequences P _SE1 , P _SE2 , ..., P _SEn are stored, P _SAT and P _SE1 , P _SE2 , ..., P _SEn are combined in the total pulse sequence generation unit 24c, and MPG _1, MPG2 _1, ..., are added one _{MPG n, PS 1 (MPG 1} ), PS 2 (MPG 2), ..., PS n, is sent to the sequencer 22 as (MPG _n).

In the sequencer 22, the PAST-SE-IVIM pulse sequence is executed in a time series as shown in FIG. 6 according to the data acquisition encoding process as shown in FIG. That is, PS ₁₁ (MPG ₁ ) as the first encoded portion of the first image, PS ₁₂ (MPG ₂ ) as the first encoded portion of the second image, and then PS 1 (MPG ₂ ) as the first encoded portion of the nth image. PS _1n (MPG _n ), then PS ₂₁ (MPG ₁ ) as the second encoded portion of the first image, then PS ₂₂ (MPG ₂ ) as the second encoded portion of the second image, ... PS _2n (MPG _n ), as the second encoded portion of the image, ... PS _m1 (MPG ₁ ) as the mth encoded portion of the first image, and then PS _m2 (MPG ₂ as the mth encoded portion of the second image , ..., Then, PS _mn (MPG _n ) is executed as the m-th encoded portion of the n-th image.

In the first example described above, the longitudinal magnetization component of one shaded area in FIG. 2 which is an area overlapping the axial section HA is saturated by the spoiler pulse SP, but shown in FIG. As described above, the longitudinal magnetization components in the two shaded areas may be saturated by the spoiler pulse SP. In this case, as shown in the presaturation sequence part of FIG. 8, two shaded areas can be selected by the α ₁ ° pulse and the slice gradient magnetic field and the α ₂ ° pulse and the slice gradient magnetic field. .

 As shown in the presaturation sequence part of FIG. 10, the two shaded area shown in FIG. 9 which is the same as the area shown in FIG. It can be selected according to the gradient magnetic field for slicing.

 Further, as shown in FIGS. 11 (a) and (b), one or two slanted line regions not only orthogonal to the lead direction and the encode direction shown so far are selected as the saturation region. be able to.

Also in this case, it can be appropriately selected according to the flip angle of the RF pulse and its component, and the strength of the gradient magnetic field for slicing.

 Next, an IR-SE-IVIM pulse sequence for Diffusion / Perfusion imaging executed by the apparatus of this embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is a diagram showing a region to be imaged, and FIG. 13 is a diagram showing one encoded portion of a PAST-SE-IVIM pulse sequence executed by the apparatus of the present embodiment. Inversion pulse section and spin echo pulse sequence It is composed of parts and parts.

The inversion pulse unit is executed prior to the spin echo pulse sequence unit, and inverts the magnetization component in the same region as the axial section HA described later by a 180 ° pulse for inversion and a gradient magnetic field for slicing by 180 °. At the same time, it is saturated by the spoiler pulse SP. Here, suppression and delay time Ti from applying to the mark addition of a 90-degree pulse inversion pulse (180 ° pulse), by appropriately setting the pulse repetition interval T _R, a signal from the CSF (cerebrospinal fluid) And increase the signal from other tissues.

 The spin echo pulse sequence part is the same as that of the PAST-SE-IVIM pulse sequence which is the first example. That is, the magnetic resonance signal is collected from the excitation site by performing magnetic resonance excitation on the axial section H A of the head PH, and a gradient magnetic field MPG (Motion) for preventing the occurrence of artifacts due to movement in the region. It is a 90 ° -180 ° pulse sequence including Probing Gradient).

 Although the above process is for one encoding, in the present embodiment, it is assumed that a plurality of n images are photographed and the number of data (the number of encodings) required for one image is m. At this time, the MPG for each image is changed. In this case, the area of MPG is the same for each image, and the intensity G, the application time d, and the interval I are changed.

That is, MPG ₁ in the _first image is G ₁ , d ₁ , I ₁ , MPG ₂ in the first image is G ₂ , d ₂ , I ₂ , ..., In the nth image. MPG _n is G _n , d _n , I _n . This factor G, d, is changed for each image.

Further, naturally, the encoding gradient magnetic field G _E is changed for each encoding.

 As described above, according to the present embodiment, the magnetization component of the moving area is suppressed by the execution of the inversion pulse section, and the spin echo pulse sequence section is provided with the spoiler pulse SP for preventing the occurrence of artifacts due to the movement. Since it is included, the signal collected by the execution of the spin echo pulse sequence part has few ghosts in the encoat direction. Therefore, the Diffusion / Perfusion imaging image generated by the data group obtained by executing the sequence multiple times is of high quality without motion artifacts. However, since the above-mentioned effects are achieved purely by devising the sequence, there are no problems with the ECG method and the echo planar method as in the past.

 In addition, since the inversion pulse part suppresses the signal from the cerebrospinal fluid, it preferably satisfies zero and increases the signals from other tissues, preferably maximizing the conditions. The influence of CSF, which can occur remarkably when used as an imaging inspection target, is suppressed. Therefore, Diffusion / Perfusion imaging in which motion artifacts are reduced and the influence of CSF is suppressed is realized.

 Furthermore, since n Diffusion / Perfusion imaging images of the same section with different motion artifacts, that is, different MPGs only, can be obtained, and their information parameters can be calculated by comparing and referring to Diffusion or Perfusion. ..

 Since the Diffusion / Perfusion imaging sequence generating means 24 in the configuration of FIG. 1 can be considered integrally with the sequencer 22, it can be configured as an integral unit or as an individual unit. It is sufficient if it is an element for executing the pulse sequence. Although the small probe 16 collects data, the whole-body probe 12 may transmit and receive data. Furthermore, in each of the above examples, the spin echo method was used as the acquisition sequence, but the present invention is not limited to this, and the field echo method or another method may be used. Of course, the part to be imaged is arbitrary.

 In addition, various modifications can be made without departing from the scope of the present invention.

 [Effects of the Invention] As described above, the invention according to claim 1 is a magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying the diffusion of water in a biological tissue and the blood flow in a tissue. The pulse sequence is executed prior to the acquisition sequence section, which collects magnetic resonance signals from the excitation site by exciting the specific region of the subject by magnetic resonance. It comprises a presaturation sequence part that saturates the magnetization component of the region overlapping with the excitation site, and the acquisition sequence part contains a gradient magnetic field for preventing the occurrence of motion-induced artifacts. To do.

 According to the first aspect of the present invention, the (longitudinal) magnetization component of the region that is moved by the execution of the presaturation sequence section is suppressed, and the gradient magnetic field for preventing the occurrence of the artifact due to the movement in the acquisition sequence section. , The signal collected by the execution of the acquisition sequence section has few ghosts. Therefore, the Diffusion / Perfusion imaging image generated by the data group obtained by executing the sequence many times is of good quality without any motion artifact.

Moreover, since the above-mentioned effects are achieved purely by devising the sequence, there is no problem in the ECG method and the ecoplanar method as in the past.

 Further, the invention according to claim 2 is the magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying the diffusion of water in a biological tissue or the blood flow in a tissue, wherein the pulse sequence is A collection sequence section that excites a specific region of the magnetic resonance by magnetic resonance and collects magnetic resonance signals from the excitation site, and is executed prior to the collection sequence section and has an overlap with the excitation site. It consists of a presaturation sequence part that saturates the magnetization component of the region, the acquisition sequence part contains a gradient magnetic field to prevent the occurrence of artifacts due to movement, and the presaturation sequence part is composed of cerebrospinal fluid. It is characterized by satisfying the conditions of suppressing the signal of and increasing the signals from other tissues.

 According to the invention of claim 2, in addition to the effect of the invention of claim 1, the presaturation sequence section satisfies the conditions of suppressing signals from cerebrospinal fluid and increasing signals from other tissues. Therefore, when the brain, spinal cord, or the like is used as an imaging inspection target, the effect of CSF, which can occur remarkably, is suppressed. Therefore, Diffusion / Perfusion imaging in which motion artifacts are reduced and the influence of CSF is suppressed is realized.

 Further, the invention according to claim 3 is the magnetic resonance imaging apparatus having a means for executing pulse sequence for quantifying the diffusion of water in living tissue and the blood flow in tissue, wherein the pulse sequence is A collection sequence section that excites a specific area by magnetic resonance and collects magnetic resonance signals from the excitation site; and an area that overlaps with the excitation site, which is executed prior to the collection sequence section. And an inversion sequence part for inversion of the magnetization component of 180 ° by 180 °, and the acquisition sequence part includes a gradient magnetic field for preventing the occurrence of artifacts due to movement.

 According to the invention of claim 3, by executing the inversion sequence part, the influence of CSF that can be particularly remarkable when the brain, spinal cord, or the like is targeted for the imaging examination is suppressed. The effect of CSF will be suppressed in the signal collected by executing the above. Therefore, the Diffusion / Perfusion imaging image generated by the data group obtained by executing the sequence many times is of high quality in which the influence of CSF is suppressed. Moreover, since the above-mentioned effect is achieved purely by devising the sequence, there is no problem in the ECG method and the echo planar method as in the conventional case.

 Further, the invention according to claim 4 is the magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying the diffusion of water in a biological tissue or the blood flow in a tissue, wherein the pulse sequence is A collection sequence section that excites a specific region of the specimen by magnetic resonance and collects a magnetic resonance signal from the excitation site, and is executed prior to the collection sequence section and overlaps with the excitation site. And a reversal sequence section for reversing the magnetization component of the region possessed by 180 °. The acquisition sequence section contains a gradient magnetic field for preventing the occurrence of artifacts due to movement, and the reversal sequence section has a cerebrospinal fluid. It is characterized by satisfying the conditions of suppressing the signal from the other and increasing the signal from other tissues.

 According to the invention of claim 4, in addition to the operation of the invention of claim 3, since the acquisition sequence part includes a gradient magnetic field for preventing the occurrence of artifacts due to movement, execution of the sequence is performed. Due to this, the signal collected is reduced in ghost, and the Diffusion / Perfusion imaging in which the influence of CSF is suppressed and the motion artifact is reduced is realized.

 Therefore, according to the present invention, it is possible to provide a magnetic resonance imaging apparatus capable of simply executing favorable Diffusion / Perfusion imaging instead of the ECG method.

[Brief description of drawings]

 FIG. 1 is a diagram showing a configuration of an embodiment of a magnetic resonance imaging apparatus according to the present invention, FIG. 2 is a diagram showing an imaging region, and FIG. 3 is a PAST-SE-IVIM pulse sequence in this embodiment. Fig. 4 is a diagram showing one encoding, Fig. 4 to Fig. 6 are diagrams showing generation, execution and data collection of a pulse sequence, Fig. 7 is a diagram showing an imaging region, Fig. 8 is PAST-SE in this embodiment. -A diagram showing one encoded portion of the first modified example of the IVIM pulse sequence, FIG. 9 is a diagram showing a region to be imaged, and FIG. 10 is a second modified example of the PAST-SE-IVIM pulse sequence in the present embodiment. Fig. 11 is a diagram showing one encoding, Fig. 11 is a diagram showing different selection methods of saturation regions, Fig. 12 is a diagram showing an imaging region, and Fig. 13 is a diagram showing the IR-SE-IVIM pulse sequence in this embodiment. It is a figure which shows one encoding. MA ... Magnet assembly, 10 ... Static magnetic field coil, 12 ... Gradient magnetic field generating coil, 14 ... Whole body probe, 16 ... Small probe, 18 ... Transmitter, 20 ... Receiver, 22 ... Sequencer, 24 ... Diffusion / Perfusion imaging Sequence generation means, 26 ... Computer system, 28 ... Monitor.

Claims (4)

[Claims] 1. A magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying water diffusion in a biological tissue or blood flow in a tissue, wherein the pulse sequence is for a specific region of a subject. A collection sequence section that excites by magnetic resonance and collects magnetic resonance signals from the excitation site, and is executed prior to the collection sequence section and saturates the magnetization component of the region that overlaps with the excitation site. A magnetic resonance imaging apparatus comprising a pre-saturation sequence unit for performing a magnetic field gradient, and the acquisition sequence unit includes a gradient magnetic field for preventing the occurrence of an artifact due to movement. 2. A magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying diffusion of water in a biological tissue or blood flow in a tissue, wherein the pulse sequence is for a specific region of a subject. A collection sequence section that excites by magnetic resonance and collects magnetic resonance signals from the excitation site, and is executed prior to the collection sequence section and saturates the magnetization component of the region that overlaps with the excitation site. The pre-saturation sequence section includes a pre-saturation sequence section, and the acquisition sequence section includes a gradient magnetic field for preventing the occurrence of motion artifacts. The pre-saturation sequence section suppresses a signal from cerebrospinal fluid and A magnetic resonance imaging device characterized in that it satisfies the condition of increasing the signals from other tissues. . 3. A magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying diffusion of water in a biological tissue and blood flow in a tissue, wherein the pulse sequence is for a specific region of a subject. A collection sequence section that excites by magnetic resonance and collects magnetic resonance signals from the excitation site, and a magnetization component of a region that overlaps with the excitation site and is executed prior to the collection sequence section. A magnetic resonance imaging apparatus comprising: an inversion sequence unit that inverts by °, wherein the acquisition sequence unit includes a gradient magnetic field for preventing the occurrence of an artifact due to a motion. 4. A magnetic resonance imaging apparatus having means for executing a pulse sequence for quantifying diffusion of water in living tissue and blood flow in tissue, wherein the pulse sequence is for a specific region of a subject. A collection sequence section that excites by magnetic resonance and collects magnetic resonance signals from the excitation site, and a magnetization component of a region that overlaps with the excitation site and is executed prior to the collection sequence section. And an inversion sequence section that inverts, the acquisition sequence section includes a gradient magnetic field for preventing the occurrence of motion artifacts, and the inversion sequence section suppresses a signal from cerebrospinal fluid and A magnetic resonance imaging device characterized by satisfying the condition of increasing signals from other tissues.