KR101535385B1 - Method and apparatus for taking a magnetic resonance imaging - Google Patents

Abstract

The present invention provides a method and an apparatus for shooting a magnetic resonance imaging (MRI) image. The method for shooting a MRI image with an MRI device according to the present invention comprises: (a) a step of applying a gradient magnetic field for selecting a slice during a specific period of time to spatial-chemically move a first chemical species and a second chemical species which are different chemical species; a step of selecting a slice of the first chemical species disposed inside a target body as a result of the spatial chemical movement to excite the first chemical species; and (c) a step of using an image signal detected from the slice of the first chemical species to obtain an MRI image of the first chemical species. The specific period of time during which the gradient magnetic field is applied is set to dispose the slice of the first chemical species inside the target body and disposed a slice of the second chemical species outside the target body.

Description

TECHNICAL FIELD The present invention relates to a magnetic resonance imaging apparatus and a magnetic resonance imaging apparatus,

The present invention relates to an apparatus and method for photographing a magnetic resonance image, and more particularly, to an apparatus and method for separating and acquiring images of different species present in a subject during magnetic resonance imaging.

Background Art [0002] A medical imaging apparatus is an apparatus for acquiring information in a subject and providing an image, such as an ultrasound diagnostic apparatus, a computed tomography (CT) apparatus, and a magnetic resonance imaging (MRI) apparatus.

Among them, Magnetic Resonance Imaging (MRI) apparatus is relatively free from imaging conditions, provides excellent contrast in soft tissues, and provides various diagnostic information images. Occupies the position.

Magnetic resonance imaging (MRI) is the imaging of the density and physicochemical properties of nuclei by nuclear magnetic resonance in the body's hydrogen nuclei using radio waves that are harmless to the human body and non-ionizing radiation.

Specifically, MRI is to diagnose the inside of the human body by converting the energy emitted from the atomic nucleus into a signal by supplying a constant frequency and energy while applying a constant magnetic field to the atomic nucleus. The proton constituting the atomic nucleus is self- Therefore, if the magnetic field is applied, the nucleus is moved around the direction of the magnetic field by aligning in the direction of the magnetic field. Thus, the image of the human body can be obtained by the nuclear magnetic resonance phenomenon by this car motion.

However, since a conventional MRI technique uses a spin-echo (MRI) sequence of a pulse sequence, a focusing pulse is first applied at a high angle of 90 °, and then a focusing pulse is applied again to 180 ° There is a problem that the time is long and there is an inaccuracy of the striking RF pulse.

Especially, the hypercholarised ¹³ C experiment, which is applied to acquire real-time metabolism images using MRI, requires a low sagging angle and fast image acquisition time, and the distribution of metabolic products is relatively low, The signal-to-noise ratio (SNR) is reduced. Conventional MRI technology can not solve such a problem.
As a related prior art document, there is U.S. Patent Application Publication No. 2010/0085046 (published on Apr. 4, 2010), but the description of the prior art has a problem that the SNR is decreased and it is difficult to acquire a fast image.

Disclosure of Invention Technical Problem [8] The present invention has been made to solve the above problems of the prior art, and it is an object of the present invention to provide an apparatus and a method for detecting a chemical We propose a method to acquire separated images of species simultaneously with one shot.

According to an aspect of the present invention, there is provided a method for acquiring a magnetic resonance imaging (MRI) image, the method comprising: (a) applying a gradient magnetic field for slice selection for a predetermined time period, (B) selecting a slice of a first species located within the subject as a result of the spatial chemical shift to excite the first species by excitation And (c) obtaining a magnetic resonance image of the first species using an image signal detected from a slice of the first species, wherein the specific time for applying the oblique magnetic field is Wherein a slice of one chemical species is located inside the subject and a slice of the second chemical species is located outside the subject.

In one aspect of the present invention, the magnetic resonance imaging method includes the steps of: (d) inverting the polarity of the oblique magnetic field so as to change the direction of the spatial chemical movement at every repetition time (TR) And further comprising:

In one aspect of the present invention, the magnetic resonance imaging method further comprises: (e) when the first chemical species and the second chemical species are spatially chemically moved as a result of the (d) Selecting a slice of a species to stimulate the second species; (f) acquiring a magnetic resonance image of the second species using an image signal detected from a slice of the second species; Wherein the spatial chemical movement of step (e) is a movement for placing a slice of the second species inside the subject and for positioning the slice of the first species outside the subject .

Further, in one aspect of the present invention, the specific time for applying the oblique magnetic field is set based on the intensity of the static field, the resonance frequency difference between the first species and the second species, and the distance of the spatial chemical shift .

Further, in one aspect of the present invention, the step of acquiring the magnetic resonance image of the first species or the second species may include acquiring the first or second species at every repetition time (TR) And recording the image signal detected from the slice in each K space, and when each of the K spaces is filled, performing inverse fast Fourier transform (IFFT) on each of the K spaces to convert the first and second species And acquiring a separated image of the image.

In order to achieve the above object, an apparatus for acquiring a magnetic resonance image according to an embodiment of the present invention is a device for acquiring a magnetic resonance image by applying a gradient magnetic field for slice selection for a specific time period, An RF pulse stimulating unit for selecting a slice of a first chemical species located inside the subject as a result of the spatial chemical shift and exciting the first chemical species; And an image acquiring unit acquiring a magnetic resonance image of the first chemical species using an image signal detected from a slice of the first chemical species, wherein a specific time for applying the oblique magnetic field is determined by a slice of the first chemical species, And a slice of the second chemical species is located outside the subject.

In one aspect of the present invention, the magnetic resonance imaging apparatus further includes a polarity reversing unit for reversing the polarity of the oblique magnetic field so that the direction of the spatial chemical movement is changed at every repetition time (TR) do.

In addition, in one aspect of the present invention, the slice selecting unit spatially chemically moves the first chemical species and the second chemical species by applying an oblique magnetic field in the polarity reversed state, and the RF pulse stimulating unit changes polarity of the oblique magnetic field The slice of the second chemical species located inside the subject is selected as the result of the spatial chemical shift after the inversion, and the image acquiring unit uses the image signal detected from the slice of the second chemical species Wherein a spatial chemical shift after polarity inversion of the oblique magnetic field positions a slice of the second species within the body of the subject, And is a movement for positioning the subject to the outside of the subject.

Further, in one aspect of the present invention, the specific time for applying the oblique magnetic field is set based on the intensity of the static field, the resonance frequency difference between the first species and the second species, and the distance of the spatial chemical shift .

According to an embodiment of the present invention, it is possible to acquire separated images of different chemical species simultaneously in one shot.

In addition, it can be applied to most pulse sequences based on gradient echo, and has a shorter image acquisition time than a pulse-sequence based on a spin echo. Therefore, T2 * is applied even in a high magnetic field with a short relaxation time This is easy.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a view showing a magnetic resonance imaging apparatus according to an embodiment of the present invention.
2 is a diagram showing a configuration of a magnetic resonance imaging apparatus according to an embodiment of the present invention.
3A and 3B are flowcharts illustrating a process of acquiring a magnetic resonance image according to an embodiment of the present invention.
4 is a diagram illustrating a pulse sequence diagram according to an embodiment of the present invention.
Figure 5 is a diagram illustrating isolated images of different species according to one embodiment of the present invention.
6 is a diagram illustrating a pulse sequence result of a chemical moving image according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "indirectly connected" .

Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a magnetic resonance imaging apparatus according to an embodiment of the present invention.

A magnetic resonance imaging apparatus 100 according to an exemplary embodiment of the present invention forms a magnetic field and generates a resonance phenomenon with respect to an atomic nucleus. The magnetic resonance imaging apparatus 100 processes magnetic resonance signal data generated from the atomic nucleus and generates magnetic resonance imaging (MRI) (Hereinafter referred to as " MRI "), and it is possible to simultaneously acquire separated images of different chemical species present in the subject by one shot.

More specifically, the magnetic resonance imaging apparatus 100 may include a hollow cylindrical shape in which an inner space 10 (hereinafter referred to as "bore") is externally shaped, The magnetic resonance signal can be obtained by bringing the subject 30 lying on the top of the body 30 into the bore 10.

1, the space in which the subject 30 is placed can be divided into x, y, and z axes, and the space in which the subject 30 is placed is parallel to the up- The axis parallel to the direction of the axis, that is, the azimuth, is set as the z axis, the axis parallel to the left-right direction of the subject 30 is set as the x axis, and the axis parallel to the up-down direction in the space is set as the y axis have.

The magnetic resonance imaging apparatus 100 may form a constant magnetic field in the bore 10 by applying an electric current. For this purpose, the bore 10 may be formed by winding a coil around the bore.

Then, when a static magnetic field is formed in the bore 10, the atomic nuclei constituting the subject 30 are aligned in the direction of the static magnetic field (z-axis direction), and precession is performed around the direction of the static magnetic field.

For reference, the wash rate of an atomic nucleus can be expressed as a resonance frequency called a Larmor frequency.

The term 'resonance frequency' can be expressed as the proportion constant and the intensity of the external magnetic field. The 'proportional constant' can be different for each kind of atomic nucleus. The unit of 'external magnetic field strength' is Tesla (T) or Gaussian The unit of resonant frequency is Hz.

For example, hydrogen ( ¹ H), which accounts for the largest proportion of the atoms that make up the human body, has a resonance frequency of 42.58 MHz, and sodium ( ²³ Na) has a resonance frequency of 11.27 MHz ( ³¹ P) has a resonant frequency of 17.2 MHz.

The magnetic resonance imaging apparatus 100 can obtain a magnetic resonance signal using the proton motion of the proton. The problem is that the resonance frequencies of the atom species of the different chemical species (hereinafter, referred to as " different chemical species & And thus, they appear at different locations on the MRI.

Spatial chemical shifts in the image due to differences in the resonance frequencies of different chemical species are called spatial chemical shifts, and spatial chemical shifts are desirable to make images of different chemical species overlap on the MRI It is a phenomenon that is not.

Accordingly, when the oblique magnetic field for selecting a slice (hereinafter, referred to as a slice oblique magnetic field) is applied, the magnetic resonance imaging apparatus 100 can set the length of the oblique magnetic field to be 'sufficiently long' By further increasing the distance of the chemical movement (distance in the z-axis direction) and alternately moving the stimulation bands of the chemical species to be imaged (hereinafter referred to as the 'interest chemical species') into and out of the subject 30, Separated images of chemical species can be obtained simultaneously with one shot.

In other words, when selecting a slice, different chemical species are already spatially separated in the image due to the spatial chemical shift phenomenon. Therefore, by increasing the distance of the spatial chemical shift by using the undesirable phenomenon in reverse, It is possible to easily acquire separated images by type.

Here, setting the length of the slope gradient magnetic field to be sufficiently long is related to the length of time during which the gradient magnetic field is applied. For example, the distance of the spatial chemical shift, which was a degree of overlapping of different chemical species on a conventional MRI, May be set to set a time for applying an oblique magnetic field so that the different chemical species have a distance of a spatial chemical shift such that they are completely separated from the inside and the outside of the object 30 to be inspected.

For reference, the longer the time the slice gradient magnetic field is applied, the greater the difference in resonance frequency between different chemical species, and the factor determining the length (time) of the slice gradient magnetic field depends on what the chemical species are Which may include the intensity of the sperm field, the difference in resonant frequency of each species and the distance of spatial chemical shifts between species.

As a result, the intensity of the static field and the resonance frequency of the chemical species present in the selected slice are already known values, so that the length of the slice gradient magnetic field can also be determined if the distance of spatial chemical movement for acquiring the separated image is determined.

Thereafter, the MRI apparatus 100 changes the direction of the spatial chemical shift by inverting the polarity of the slice gradient magnetic field every repetition time (TR), and changes the distance of the spatial chemical shift between different chemical species Directional distance), it is possible to move the stimulation bands of the species of interest alternately between the inside and the outside of the subject, and at every repetition time (TR) Can selectively excite the bands of < RTI ID = 0.0 >

For reference, atomic nuclei aligned by an external magnetic field carries out a kinetic motion with a resonant frequency, and the magnetization vector sum of several nuclei can be represented by a single net magnetization.

Here, the z-axis component of the average magnetization, that is, the component parallel to the direction of the magnetic field can not be measured, and only the x-axis and the y-axis of the average magnetization can be detected.

Therefore, in order to obtain a magnetic resonance signal, the average magnetization must be located on the xy plane. This is called excitation to the nucleus, and the MRI apparatus 100 uses an RF pulse to excite the nucleus, flip angle to the sperm field to generate a high frequency magnetic field in the sperm entry space.

To this end, the magnetic resonance imaging apparatus 100 may include a transmission coil for transmitting an RF stimulation signal and a reception coil for receiving a magnetic resonance signal, that is, a video signal, emitted from the stimulated nucleus.

The MRI apparatus 100 may receive a video signal emitted from a chemical species located inside the subject 30 at every repetition time TR and fill a frequency region called a K space constituting an image of the slice .

Here, the K space can exist in different chemical species, and can constitute a two-dimensional Fourier space.

Thereafter, when the scan for the subject 30 is completed and the K space for each chemical species is filled, the MRI apparatus 100 performs an inverse fast Fourier transform (IFFT) Separated images of different species can be obtained simultaneously.

For reference, the MRI apparatus 100 includes a modulation circuit for modulating a high-frequency output signal into a pulsed signal, an RF power amplifier for amplifying the pulsed signal, a preamplifier for amplifying a magnetic resonance signal received by the receiving coil, A phase detector for receiving the magnetic resonance signal from the preamplifier, a phase detector for detecting the phase, an A / D converter for converting the analog signal obtained by the phase detection into a digital signal, a K space for storing the digitally converted resonance signal, . ≪ / RTI >

As described above, the present invention can simultaneously acquire separate images of different chemical species, that is, a plurality of chemical species, at one time of photographing. For convenience of explanation, two different chemical species Quot; species " and " second species ") at the same time.

For reference, the movement of different chemical species (first chemical species, second chemical species) referred to in the present invention or the movement of slices of different chemical species (first chemical species, second chemical species) It means movement in an image, not each species moving inside.

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

The MRI apparatus 100 according to an embodiment of the present invention may include a slice selector 110, an RF pulse stimulator 120, a polarity reverser 130, and an image acquirer 140.

The slice selecting unit 110 may apply a slice gradient magnetic field for a specific time to select a slice to acquire an image.

Here, the specific time for applying the slice gradient magnetic field can be set so that the slice of the first chemical species is located inside the subject and the slice of the second chemical species is located outside the subject.

That is, since the distance of the spatial chemical shift between the first chemical species and the second chemical species is longer due to the slice gradient magnetic field applied by the slice selection unit 110 for the specific time, the slice of the first chemical species is formed inside the subject And the slice of the second chemical species may be located outside the subject, and the slice selecting unit 110 may select a slice of the first chemical species located inside the subject.

For reference, when the polarity of the slope gradient magnetic field is reversed by the polarity inversion section 130 described later and the direction of the spatial chemical movement is changed, the slice selection section 110 selects the slice gradient magnetic field Whereby the slice of the first chemical species located inside the subject can be positioned outside the subject and the slice of the second chemical species located outside the subject can be positioned inside the subject.

On the other hand, the RF pulse stimulating unit 120 applies a stimulated RF pulse to a slice of a chemical species alternately positioned inside the subject for every repetition time (TR) at a time of applying the stimulation RF pulse to a specific flip angle ) Can be applied.

For reference, magnetic resonance signals such as ³ He, ¹²⁹ Xe, and ¹³ C can measure very small atoms compared to hydrogen using hyper-polarization, which increases the magnetic resonance signal by a factor of up to 1,000 times, In the case of hyperpolarized atoms, it is not possible to use a high-angle stimulation pulse. Therefore, a low grating angle and a fast image acquisition time are required.

Accordingly, the RF pulse stimulating unit 120 can adjust the sagging angle for applying stimulated RF pulses at every repetition time (TR) according to the type of atoms used in MRI imaging.

On the other hand, the polarity inversion unit 130 can change the direction of the spatial chemical shift by reversing the polarity of the slice gradient magnetic field every repetition time TR.

For example, when the slice of the first chemical species is located inside the subject due to the slice gradient magnetic field applied by the slice selecting unit 110 for a specific time during the odd repetition time TR, If the polarity inversion unit 130 inverts the polarity of the slope gradient magnetic field in the even-numbered repetition time TR, the direction of the spatial chemical shift is changed, The slice of the second chemical species, which is located inside the subject, is applied to the inside of the subject by applying a slice gradient magnetic field for a specific period of time with the polarity reversed, May be located outside the subject.

On the other hand, the image acquisition unit 140 may receive a magnetic resonance signal, i.e., an image signal, received from a chemical species located inside the subject at every repetition time TR and fill the K space constituting the image of the slice .

That is, the direction of the spatial chemical movement is changed by the polarity inversion unit 130 every even-numbered repetition time TR and the odd-numbered repetition time TR, and the slice selecting unit 110 applies the slice- The slices of one chemical species and the second chemical species are alternately located inside the subject.

Then, each time the RF pulse stimulating unit 120 applies the stimulating RF pulse to the inside of the subject, the image obtaining unit 140 obtains the image signal from the slice of the chemical species located inside the subject at every repetition time TR And can fill in the K space corresponding to the chemical species.

Here, the K space may constitute a two-dimensional Fourier space, and if the K space for each slice of each of the first and second species is filled, the image acquiring unit 140 may inversely Fourier- (IFFT) to obtain separate images of the first species and the second species simultaneously.

3A and 3B are flowcharts illustrating a process of acquiring a magnetic resonance image according to an embodiment of the present invention.

3A and 3B can be performed by the magnetic resonance imaging apparatus 100 shown in FIG. 2. Hereinafter, the flow chart of FIG. 3 will be mainly described with reference to the magnetic resonance imaging apparatus 100. FIG.

First, the magnetic resonance imaging apparatus 100 selects a slice by applying a slice gradient magnetic field to a specific length of time (S301).

Here, the 'specific time' for applying the slice gradient magnetic field is a slice of the first chemical species and the second chemical species that were present together in the subject, the slice of the first chemical species is inside the subject, the slice of the second chemical species is And a time required to increase the spatial chemical movement distance so as to be located outside the subject.

After S301, the magnetic resonance imaging apparatus 100 detects an image signal generated by the first chemical species from the slice of the first chemical species located inside the test object at the odd-numbered repeat time TR (S302).

After S302, the magnetic resonance imaging apparatus 100 fills the K space constituting the image of the slice of the first chemical species (S303).

After S303, the magnetic resonance imaging apparatus 100 inverts the polarity of the slice gradient magnetic field at the even-numbered repetition time TR to apply a gradient magnetic field (S304).

Thereby, the direction of the spatial chemical shift can be changed, and the distance of the spatial chemical shift can be increased so that the slice of the second species is located inside the subject and the slice of the first species is located outside the subject.

After S304, the magnetic resonance imaging apparatus 100 detects a video signal generated from the slice of the second chemical species located inside the inspected object (S305).

After S305, the magnetic resonance imaging apparatus 100 fills the K space constituting the image of the slice of the second species (S306).

After S306, the magnetic resonance imaging apparatus 100 repeats the processes of S302 to S306 until all the K spaces for the slice of the first species and the slice of the second species are all filled (S307).

After S307, the magnetic resonance imaging apparatus 100 acquires a separated image by performing inverse Fourier transform (IFFT) on each K space for the slice of the first species and the slice of the second species (S308).

4 is a diagram illustrating a pulse sequence diagram according to an embodiment of the present invention.

4 (a) is a pulse sequence diagram used for conventional MRI acquisition, and FIG. 4 (b) is a pulse sequence diagram used for simultaneously acquiring MRI of different species of the present invention.

4A and 4B, the polarity of the oblique magnetic field used for slice selection is conventionally constant at every repetition time TR. However, in the present invention, the slope gradient magnetic field It can be seen that the polarity is inverted and the oblique magnetic field is applied.

4A and 4B, there is no significant difference in the length of time during which the slice gradient magnetic field is applied. However, as described above, the length of time during which the slice gradient magnetic field of the present invention is applied is May be set to be " long enough " than conventional, which may be determined corresponding to the spatial chemical shift distance value input from the user.

Figure 5 is a diagram illustrating isolated images of different species according to one embodiment of the present invention.

5 (a), the slice of the first chemical species is located inside the subject and the slice of the second chemical species is located outside the subject due to the slice gradient magnetic field applied during the above-mentioned specific time period You can see that the distance has increased.

5 (b) shows a state in which the polarity of the slice gradient magnetic field is inverted, the direction of the spatial chemical movement is changed, and the slice gradient magnetic field is applied for a specific time in the polarity reversed state, It can be seen that the slice of the first species is located outside the subject and the slice of the second species is located inside the subject.

The magnetic resonance imaging apparatus 100 detects an image signal generated by a first chemical species from a slice corresponding to a first chemical species located inside the subject at every odd repetition time TR to detect an image of the slice of the first chemical species The frequency region of the constituent K-space is filled, and the polarity of the slice gradient magnetic field is reversed. Thereafter, the image signal for generating the second chemical species from the slice corresponding to the second chemical species located inside the subject for every even- And the frequency domain of the K space constituting the image of the slice of the second species is detected, so that separate images of the first species and the second species can be simultaneously obtained.

6 is a diagram illustrating a pulse sequence result of a chemical moving image according to an embodiment of the present invention.

FIG. 6 can assess the metabolic capacity of tissue by monitoring the metabolic process in which pyruvic acid is converted to lactate as a result of injecting hypervariable pyruvate into the blood vessels of rats.

Conventionally, a pulse sequence of pyruvic acid and lactic acid inevitably appears in one voxel. However, the present invention is not limited to the case where pyruvic acid and lactic acid are spatially separated as shown in FIGS. 6A and 6B The pulse sequence can be acquired at the same time.

In FIG. 6 (a), it can be seen that a large signal of lactic acid occurs at a position corresponding to the kidney of the rat, because metabolism in which pyruvic acid is converted into lactic acid is very actively generated in the kidney.

In FIG. 6 (b), since pyruvic acid is injected into blood vessels, it can be seen that signals are evenly distributed throughout the blood vessels.

For reference, since the conventional MRI technique uses a spin-echo series MRI pulse sequence, a focusing pulse is first applied at a high-angle of 90 °, and then a focusing pulse there is a problem in that there is a long time until the refocusing pulse is applied and inaccuracies of the high-stiffness stimulating RF pulse.

Especially, the hypercholarised ¹³ C experiment, which is applied to acquire real-time metabolism images using MRI, requires a low sagging angle and fast image acquisition time, and the distribution of metabolic products is relatively low, The signal-to-noise ratio (SNR) is reduced. Conventional MRI technology can not solve such a problem.

However, the present invention utilizes the spatial chemical shift generated by the slice gradient magnetic field to alternately move the stimulus bands of the species of interest into and out of the subject to separate images of different species simultaneously Which can be applied to most pulse sequences based on gradient echo and has the advantage of a shorter image acquisition time than a pulse echo based pulse sequence.

In particular, in the case of high magnetic field MRI, which acquires metabolism images using hyperpolarized ¹³ C, there is a limitation of the imaging time due to T2 * relaxation time. However, when the present invention is applied, Images of a plurality of metabolites can be acquired at a high speed, and the above-described conventional problems can be solved.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: Magnetic Resonance Imaging Device
110: Slice selector
120: RF pulse stimulating portion
130: polarity reversal part
140:

Claims (9)

A method for acquiring a magnetic resonance image by a MRI apparatus,
(a) applying a gradient magnetic field for slice selection for a specific time period to spatially chemically move the first chemical species and the second chemical species, which are different chemical species;
(b) selecting a slice of a first species located within the subject as a result of the spatial chemical shift, thereby exciting the first species; And
(c) obtaining a magnetic resonance image of the first species using an image signal detected from a slice of the first species; and
, ≪ / RTI &
Wherein a specific time for applying the oblique magnetic field is set such that a slice of the first chemical species is located inside the subject and a slice of the second chemical species is located outside the subject .
The method according to claim 1,
(d) applying an oblique magnetic field by inverting the polarity of the oblique magnetic field so that the direction of the spatial chemical movement is changed for each repetition time (TR)
Wherein the magnetic resonance imaging method further comprises:
3. The method of claim 2,
(e) stimulating the second species by selecting a slice of a second species located within the subject when the first species and the second species are spatially chemically moved as a result of step (d) ; And
(f) obtaining a magnetic resonance image of the second species using an image signal detected from a slice of the second species
Further comprising:
Wherein the spatial chemical movement of step (e) is a movement for locating the slice of the second species inside the subject and for positioning the slice of the first species outside the subject. Image capturing method.
The method according to claim 1,
Wherein the specific time for applying the oblique magnetic field is set based on intensity of a static field, a resonance frequency difference between the first species and the second species, and a distance of the spatial chemical shift.
The method of claim 3,
Wherein obtaining a magnetic resonance image of the first species or the second species comprises:
Recording a video signal detected from a slice of the first chemical species or the second chemical species in each K space for each repetition time (TR); And
Acquiring a separated image of the first species and the second species by performing inverse fast Fourier transform (IFFT) on each of the K spaces when each of the K spaces is filled;
And a magnetic resonance imaging method.
An apparatus for acquiring a magnetic resonance image,
A slice selecting unit for applying a gradient magnetic field for slice selection for a specific time to spatially chemically move the first chemical species and the second chemical species, which are different chemical species;
An RF pulse stimulating unit for selecting a slice of the first chemical species located inside the subject as a result of the spatial chemical shift and exciting the first chemical species; And
An image acquiring unit for acquiring a magnetic resonance image of the first chemical species using an image signal detected from a slice of the first chemical species;
, ≪ / RTI &
Wherein the predetermined time for applying the oblique magnetic field is set such that a slice of the first chemical species is located inside the subject and a slice of the second chemical species is located outside the subject. .
The method according to claim 6,
A polarity reversing unit for reversing the polarity of the oblique magnetic field so that the direction of the spatial chemical movement is changed every repetition time (TR)
Wherein the magnetic resonance imaging apparatus further comprises:
8. The method of claim 7,
Wherein the slice selector comprises:
Applying an oblique magnetic field in a state where the polarity is inverted to spatially chemically move the first chemical species and the second chemical species,
The RF pulse magnetic-
Selecting a slice of a second chemical species located inside the subject as a result of spatial chemical shift after polarity inversion of the oblique magnetic field to stimulate the second chemical species,
The image acquiring unit may acquire,
Acquiring a magnetic resonance image of the second species using an image signal detected from a slice of the second species,
Wherein the spatial chemical shift after polarity inversion of the oblique magnetic field is a movement for placing a slice of the second chemical species inside the subject and for positioning the slice of the first chemical species outside the subject Resonance imaging device.
The method according to claim 6,
Wherein the specific time for applying the oblique magnetic field is set based on intensity of a static field, a resonance frequency difference between the first species and the second species, and a distance of the spatial chemical movement.

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