JPH08257005A - Collecting method for magnetic resonance signal, magnetic resonance imaging method and magnetic resonance imaging device - Google Patents

Abstract

PURPOSE: To provide a collecting method for magnetic resonance signals, magnetic resonance imaging method and magnetic resonance imaging device having high S/N ratio 'reverse MTC effect' and by which a MR signal value with high atomic nuclear pool which contributes to imaging and utilizing of free water or the like can be obtained. CONSTITUTION: A designated atomic nuclear pool among at least two kinds of atomic nuclear pools in at least two kinds of atomic nuclear pools in a subject which have a conjugation relation by means of at least one of chemical transformation phenomenon and cross relaxation phenomenon is excited frequency-selectively by means of high frequency pulse having a frequency band width substantially coinciding with the band width one the frequency spectrum of this designated atomic nuclear pool, and a MR signal of the atomic pool which reflects at least one phenomenon is collected after this excitation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance signal acquisition method, a magnetic resonance imaging method and a magnetic resonance imaging apparatus, and more particularly to a "Reverse MTC (Magnetization T
The present invention relates to a signal acquisition method, an imaging method, and an imaging device suitable for medical use that utilize the “ransferContrast) effect”.

[0002]

2. Description of the Related Art Conventionally, as one method of magnetic resonance imaging, there has been known a method of utilizing an MTC (Magnetization Transfer Contrast) effect to obtain different contrast images depending on the presence or absence of the MTC effect of a living body. A specific example of this imaging method is disclosed in US Pat. No. 5,050,609 (“Magnetization Transfer Contrast and Proton Re-l”).
axation and Use Thereof In Magnetic Resonance Imag
ing ", by Robert S. Balaban et al.).

The MTC effect is S by "Forsen &Hoffman"
It originated in the T (Saturation Transfer) method (Forsen
et al., Journal of Chemical Physics, vol.39 (11),
pp.2892-2901 (1963) ”), for example, chemical exchange and / or cross relaxation (cross exchange) of protons between multiple species of nuclear pools such as free water and macromolecules.
relaxation).

MR (Magnet) of free water and polymer protons
ic Resonance) relationship shows that free water with a long T ₂ relaxation (transverse relaxation) time (T ₂ = about 100 msec) and a polymer with a short T ₂ relaxation time (T ₂ = about 0.1 to 0.2 msec) have the same frequency. Resonates with. The left-hand column of FIG. 9 (a) shows the frequency spectrum relationship between free water and the polymer, and the right-hand column of FIG. 9 (a) shows the exchange / relaxation relationship of magnetization (FIG. 9 (b)).
The same applies to (c)). The signal value of free water is T ₂
Due to the long relaxation time, the signal value after the Fourier transform shows a sharp peak with a narrow half width as shown in the figure. On the other hand, movement is restricted between polymers such as proteins (re
The signal value of stricted proton has a wide half-value width after Fourier transform because the T ₂ relaxation time is short, and does not appear as a peak on the spectrum.

In the conventional imaging method utilizing the MTC effect, when the peak of free water is considered to be the center frequency, a frequency selective prepulse (MTC) as shown in FIG.
Pulse) to excite a frequency deviated from the resonance frequency of free water by, for example, 500 Hz (off-resonance excitation). As a result, the magnetization Hf of free water is moved to the magnetization Hr of the polymer, and the MR signal value from the protons of the polymer decreases as shown in FIG. It will decrease at a higher rate. Therefore, since there is a difference in signal value between the site where chemical exchange and / or cross relaxation between free water and polymer is reflected and the site where it is not, different contrast images can be obtained, and lesions such as living body and normal tissues can be obtained. It can be used to identify

[0006]

However, the conventional MTC effect is to move the magnetization Hf of free water protons to the magnetization Hr of polymer protons by off-resonance excitation to lower the MR signal value of free water, so to speak. It was based on "negative" magnetization transfer. As a result, the S / N ratio was low and the resolution of image contrast was low.

Further, since it is necessary to apply the MTC pulse before the image acquisition sequence or to create an image by the addition averaging method, there is a tendency that the entire imaging time becomes long.

The present invention has been made in view of the above situation, and in particular, it is possible to increase the MR signal value of a nuclear pool of free water or the like, which has a high S / N ratio utilizing the "positive" MTC effect. It is an object of the present invention to provide an MR signal acquisition method, a magnetic resonance imaging method, and a magnetic resonance imaging apparatus.

[0009]

In order to achieve the above object, the method of collecting magnetic resonance signals according to the present invention provides at least the inside of a subject having a binding relationship due to at least one of a chemical conversion phenomenon and a cross relaxation phenomenon. An MR signal obtained by a magnetic resonance phenomenon of two types of nuclear pools is collected, and a designated nuclear pool among the at least two types of nuclear pools is substantially set to a bandwidth on a frequency spectrum of the designated nuclear pool. The method includes the steps of frequency-selectively exciting with a high-frequency pulse having a matched frequency bandwidth, and collecting the MR signal of the designated nucleus pool reflecting the at least one phenomenon after the excitation.

Preferably, the designated pool of nuclei is a collection of nuclei having a longer transverse relaxation (T ₂ ) time than the other pools of nuclei. For example, the designated nuclear pool is a collection of protons of free water in the subject.
Further, for example, the high-frequency pulse is a high-frequency pulse that tilts the nuclear spin flip angle to 90 ° or more.

More preferably, the high frequency pulse is 90
° pulse. For example, the 90 ° pulse is a gradient field echo (FE) method, a fast gradient field echo (Fast FE) method, a spin echo (SE) method, a fast spin echo (Fast SE) method in magnetic resonance imaging, and echoes thereof. Echo Planar Imaging (EPI)
It is an excitation pulse of one of the pass sequences in the method. In addition, for example, the selective excitation step and the signal acquisition step include a gradient field echo (FE) method,
Fast Gradient Field Echo (Fast F
E) method, spin echo (SE) method, fast spin echo (Fast SE) method, and an echo planar imaging (EPI) method to which these echo methods are applied are executed in any pulse sequence.

More preferably, the high frequency pulse is 18
It is a 0 ° pulse. For example, the 180 ° pulse is an inversion pulse of a pulse sequence of either the inversion recovery (IR) method or the fast inversion recovery (Fast IR: FLAIR) method in the magnetic resonance imaging method. For example, the selective excitation step and the signal acquisition step are performed in a pulse sequence of either inversion recovery (IR) method or fast inversion recovery (FastIR: FLAIR) method in magnetic resonance imaging.

Further, for example, the bandwidth of the high frequency pulse is preferably 800 Hz or less.

Further, for example, the selective excitation step and the signal acquisition step are executed by a pulse sequence of a saturation transfer (ST) method in NMR spectroscopy.

Further, the magnetic resonance imaging method of the present invention collects MR signals due to the magnetic resonance phenomenon of at least two kinds of nuclear pools in the subject having a binding relationship due to at least one of the chemical conversion phenomenon and the cross relaxation phenomenon. Frequency of a designated nuclear pool of the at least two types of nuclear pools with a first high frequency pulse having a frequency bandwidth substantially matching the bandwidth on the frequency spectrum of the designated nuclear pool. A first step of selectively exciting, a second step of collecting the MR signal of the designated nucleus pool reflecting the at least one phenomenon after the first step, and the at least two kinds of nucleus pools Is a second high bandwidth having a frequency bandwidth wider than the bandwidth on the frequency spectrum of the designated nuclear pool. A third step of selectively exciting frequency wave pulse, after the step of the third excitation,
A fourth step of collecting MR signals of the designated nucleus pool reflecting the at least one phenomenon, and forming a contrast image for each excitation based on the MR signals collected by the second and fourth steps And a fifth step of performing.

Furthermore, the magnetic resonance imaging apparatus of the present invention comprises a designated one of the at least two kinds of nuclear pools in the subject having a binding relationship due to at least one of the chemical conversion phenomenon and the cross relaxation phenomenon. An MR signal by a magnetic resonance phenomenon of a nuclear pool is collected, and the designated nuclear pool is frequency-selectively selected by a high-frequency pulse having a frequency bandwidth substantially matching the bandwidth on the frequency spectrum of the designated nuclear pool. And a means for collecting the MR signal of the designated nucleus pool reflecting the at least one phenomenon after the excitation.

[0017]

In the signal collecting method and the imaging apparatus of the present invention, frequency selective using a high frequency pulse set to a narrow band, that is, a bandwidth substantially the same as the frequency band of a designated nucleus pool (for example, protons of free water). Be excited by. This excitation hardly saturates (as much as possible) the magnetization spins of other nuclear pools (for example, polymer protons) that are in a chemical bond relationship (chemical exchange and / or cross relaxation) with this nuclear pool. The magnetized spins are fully saturated. Therefore, after excitation by this narrow band selective excitation pulse (bandwidth is 800 Hz, for example), the magnetization of the other nuclear pool moves to the magnetization of the designated nuclear pool due to chemical exchange and / or cross relaxation, and, for example, The MR signal value of a nuclear pool such as free water having a long transverse relaxation (T ₂ ) time increases. Therefore, the S / N ratio of the MR signal of the designated nucleus pool is increased.

As described above, the MTC effect of the present invention acts to increase the MR signal value of the designated nucleus pool such as protons of free water, so that the conventional MR signal value is decreased by "n".
The "positive" MTC against the "ega-tive" MTC effect
This "positive" MTC can be positioned as an effect
The effect will be referred to as "Reverse MTC effect" by the inventor.

When magnetic resonance imaging or spectroscopy by the ST method is performed using the "Reverse MTC effect", the resolution of the contrast image can be increased by the increase of the MR signal value and the analysis capability of the spectroscopy can be improved. Can be improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A first embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to.

A schematic configuration of the magnetic resonance imaging apparatus according to this embodiment is shown in FIG. This magnetic resonance imaging apparatus includes a magnet unit for generating a static magnetic field, a gradient magnetic field unit for adding position information to the static magnetic field, a transceiver unit for receiving an MR signal, a system control unit, and a control unit responsible for image reconstruction. And a calculation unit.

The magnet section includes, for example, a superconducting magnet 1.
A static magnetic field power supply 2 for supplying a current to the magnet 1 is provided, and a static magnetic field H ₀ is generated in the Z-axis direction of the cylindrical opening into which the subject P is loosely inserted. The magnet portion is provided with a shim coil 14 for primary shimming.
Shimming can be performed by adjusting the current supplied to No. 4.

The gradient magnetic field section is composed of X, which is incorporated in the magnet 1.
Three sets of gradient magnetic field coils 3x to 3z in the Y- and Z-axis directions, a gradient magnetic field power source 4 for supplying a current to the gradient magnetic field coils 3x to 3z, and a gradient magnetic field sequencer in a sequencer 5 for controlling the power source 4. 5a and. This gradient magnetic field sequencer 5a is provided with a computer, and the controller 6 (equipped with a computer) of the entire apparatus is used to execute the FE method, SE method,
A signal for instructing a collection pulse sequence related to the high speed FE method, the high speed SE method, etc. is received. This allows the gradient magnetic field
The sensor 5a controls the application and strength of each gradient magnetic field in the X, Y, and Z axis directions according to the commanded pulse sequence, and these gradient magnetic fields can be superimposed on the static magnetic field H ₀ . In this embodiment, a gradient magnetic field in the Z-axis direction out of the three axes orthogonal to each other is defined as a slice gradient magnetic field G _S, and X
The axial magnetic field G _R is used as a read gradient magnetic field G _R , and the Y axial direction magnetic field is used as a phase encoding gradient magnetic field G _E.

The transmission / reception unit includes a high-frequency coil 7 arranged near the subject P in the imaging space inside the magnet 1, a transmitter 8T and a receiver 8R connected to the coil 7, and a transmitter 8T. And an RF sequencer 5b (equipped with a computer) in the sequencer 5 for controlling the operation of the receiver 8R. Under the control of the RF sequencer 5b, the transmitter 8T and the receiver 8R supply a high-frequency coil 7 with a pre-pulse for exciting nuclear magnetic resonance (NMR) and an RF current pulse of Larmor frequency, while the high-frequency coil 7 is operated.
The received MR signal (high frequency signal) is subjected to various kinds of signal processing to form a corresponding digital signal.

Further, in addition to the controller 6 described above, the control / calculation unit inputs the digital data of the MR signal formed by the receiver 8R, calculates the image data, and stores the calculated image data. The storage unit 11, the display unit 12 for displaying an image, and the input unit 13 are provided. The arithmetic unit 10 specifically performs processing such as arrangement of actually measured data in a two-dimensional Fourier space, which is a memory space, and Fourier transform for image reconstruction. The controller 6 is a gradient magnetic field sequencer 5a and RF.
While synchronizing the sequencer 5b, the operation content and operation timing of both are controlled.

Next, the operation of this embodiment will be described.

When the magnetic resonance imaging apparatus is activated, the controller 6 executes a predetermined main program,
The gradient magnetic field sequencer 5a and the RF sequencer 5b are instructed to start the pulse sequence of the high speed SE method shown in FIG. 2, for example. The gradient magnetic field sequencer 5a controls the slice gradient magnetic field G _S , the read gradient magnetic field G _R , and the phase encoding gradient magnetic field G _E based on the sequence shown in FIG. In parallel with this, the RF sequencer 5b uses the sequence shown in FIG.
A 0 ° RF pulse is applied.

As shown in FIG. 3, the 90 ° RF pulse applied in this embodiment has a long sidelob of the sinc function to increase its π number, and the overall pulse length is set to be long. is there. The pulse length of this 90 ° RF pulse is set so that its excitation range substantially matches the bandwidth on the frequency spectrum of the pool of nuclei targeted by the subject.

Now, one of the two types of atomic nuclei in the analyte, which have a chemical exchange and / or cross relaxation bond relationship, is a proton of free water, and the other is a proton of a polymer. Is used as the target nucleus pool.
In this case, the pi number of the 90 ° RF pulse is, for example, preferably (-4, + 1) π, and the pulse length is set to 22 msec. As a result, the excitation bandwidth of the 90 ° RF pulse is 227.
The frequency becomes Hz, which is a "narrow band" that substantially matches the bandwidth of the spectrum curve of free water as shown in FIG. Further, for example, when the number of π = ± 2π and the pulse length = 15 msec, the excitation bandwidth is “narrow band” of 267 Hz. The conventional RF pulse band for excitation is a short pulse in a normal sequence, and in the case of ± 1π (2 msec), the bandwidth is 1000 H.
In the case of z and ± 2π, "wide band" with bandwidth = 2000 Hz
Is set to

The pulse sequence according to the fast SE method of the present embodiment is characterized by using the 90 ° RF pulse set in the "narrow band" as described above.

Now, returning to FIG. 2, this sequence will be described. First, the slicing gradient magnetic field G _S is applied from the gradient magnetic field power source 4 via the gradient magnetic field coils 3z, 3z, and when the gradient magnetic field G _S rises to a constant value, it is transmitted via the transmitter 8T and the high frequency coil 7. Narrow band 90 ° RF
The pulse is applied only once. As a result, a region having a predetermined slice width of the subject is selected, and the proton spins of free water in the plane are frequency-selectively excited, so that y
Flip up to the'axis (rotational coordinate). At this time, the 90 ° RF pulse sufficiently excites only free water in a frequency-selective manner, and its bandwidth is narrow as shown in FIG. 4, so that it is extremely narrow to excite proton spins of the polymer. Limited to band. That is, the proton spins of the polymer are hardly excited (saturated) by the narrow band 90 ° RF pulse described above.

Therefore, the magnetization H _f due to the proton spins of free water and the magnetization H _r due to the proton spins of the polymer are in equilibrium before the excitation while maintaining their chemical bonding relationship as shown in FIG. 5 (a). What was in the state, after excitation,
As shown in FIG. 7B, the magnetization moves from the magnetization H _{r of the} polymer that is not excited (unsaturated) to the magnetization H _f of the sufficiently excited (saturated) free water.

In the sequence, the read gradient magnetic field G _R is then applied via the gradient magnetic field coils 3x and 3x together with the reversal of the slice gradient magnetic field G _S. This is applied to the spin phase aligned in G _R direction in the slice plane is so aligned at the center time of each echo.

Next, the first 180 ° RF pulse is applied together with the slicing gradient magnetic field G _S. 18 here
The 0 ° RF pulse is set to a normal broadband pulse.
As a result, the proton spin of free water is 180 degrees and y '
Rotate around an axis. Further, the first phase-encoding gradient magnetic field G _E = A is applied from the gradient magnetic field power source 4 to the subject P via the gradient magnetic field coils 3y and 3y, and then applied via the gradient magnetic field coils 3x and 3x. with use gradient G _R, the first spin echo signal R1 is collected through the RF coil 7.

After that, the inverted phase encoding gradient magnetic field G _E = -A is applied. This is a pseudo echo (stim
180 ° R to avoid image deterioration due to modulated echo)
This is because the encode position is returned to the center position (ke = 0) in the phase encode direction on the k space when the F pulse is applied.

Next, the second 180 ° RF pulse is applied together with the slice gradient magnetic field G _S , and then the second phase encoding gradient magnetic field G _E = B is applied. And
The second spin echo signal R2 is the read gradient magnetic field G
_With the application of _R , it is collected via the high frequency coil 7.

Similarly, the third and fourth spin echo signals R3 and R4 are collected.

The collection of the four echoes R1 to R4 is repeated every high frequency excitation by a predetermined number of narrow band 90 ° RF pulses.

The echo signals thus collected are sequentially
It is sent to the receiver 8R, where it undergoes processing such as amplification, intermediate frequency conversion, phase detection, and low frequency amplification, and is then A / D converted and generated into echo data. In the arithmetic unit 10, the echo data is arranged in a memory area corresponding to the k space that can be Fourier transformed. Then, it is reconstructed into an image in the real space by the two-dimensional Fourier transform. This image is stored in the storage unit 13 and the display 1
4 is displayed.

By using the narrow band 90 ° RF pulse as described above, the magnetization H _r caused by the spin of the polymer preserved so as not to be saturated at the time of excitation is excited, and thereafter, chemical exchange and / or cross relaxation is performed. Can be moved to free water. As a result, the value of MR signal (echo signal) of free water reflected in imaging can be calculated by the conventional "nega-tiv".
A higher signal value can be obtained, the S / N ratio can be improved, and the resolution of the image contrast can be improved, as compared with the case of collecting using the e ″ MTC effect. Since it is improved, it is not necessary to use the averaging method that has been conventionally performed, and since the MTC pulse is not necessary, the imaging time can be shortened.

Even in the ordinary MR signal acquisition without applying the MTC pulse (see FIG. 9), since the 90 ° selective excitation pulse has a wide bandwidth of about 1000 Hz in the related art, the MTC effect actually occurs. I was observing a low signal value of free water. However, by implementing the present invention, such a situation can be avoided, and a high MR signal value of free water that contributes to imaging can be obtained.

The sites where the MTC effect is reported to be high in the human body are brain white matter / gray matter, liver, cartilage, kidney and the like. Therefore, the signal values of these parts are
It has been lowered by the e ″ MTC effect. By using the present invention, the signal at these sites is increased.

As described above, an imaging sequence that causes the "Reverse MTC effect" and a normal imaging sequence that does not cause the MTC effect are individually performed on the same portion including the site and tissue that exert the MTC effect. It is possible to activate and identify the lesion and normal tissue from the two images obtained by the activation. The applicant has actually changed the bandwidth of the 90 ° excitation pulse, and the MTC effect has been observed by the FE method.
The signal value of PVA free water was measured using a cohol (PVA) phantom. The measurement result is shown in FIG. In the graph shown in the figure, the vertical axis represents the value obtained by normalizing the PVA signal value with the reference water signal, and the horizontal axis represents the frequency band of the 90 ° excitation pulse. Frequency band 10
It was found that the signal value was improved almost twice when the frequency was changed from 00 Hz to 230 Hz. It was also confirmed from this graph that the "Reverse MTC effect" substantially appears when the bandwidth becomes about 800 Hz or less.

Further, regarding the influence of the flip angle of the narrow band RF pulse on the "Reverse MTC effect", the applicant has obtained the relationship shown in FIG. In the figure, the vertical axis is PVA.
Signal value (arbitrary), and the horizontal axis shows the flip angle. When the frequency band of the slice-selective excitation pulse is narrow (see black squares in the figure), the “Reve
The signal value increases due to the “rse MTC effect.” From the graph shown in the figure, in the case of a narrow band 90 ° pulse, since the frequency bandwidth (BW) is 227 Hz, the flip angle is 9
It was also found that it is desirable that the angle be 0 ° or more.

In the above embodiment, this "Reverse MTC effect"
Was applied to the imaging by the high-speed SE method, but other than this, the SE method, the FE method, the high-speed FE method, etc.
It can also be applied to the EPI (echo planar imaging) method of the E method system, and can be performed by replacing the excitation pulse in those sequences with the narrow band RF pulse described above.

The narrow band RF pulse related to the "Reverse MTC effect" of the present invention is not limited to the FE and SE EPI,
IR method and high-speed FI method (Fast IR method: FLAIR)
Method) IR (inversion recovery) pulse. In the case of the IR method, the T1 time of a substance having an MTC effect is changed by the "Reverse MTC effect". When the IR pulse is set to a narrow band, the "Reverse MTC effect" occurs as shown in Fig. 10 (a) to (b), and the observed signal (free water) has a "Positive" MTC effect. High signal due to the contribution of nature.

Further, the narrow band RF pulse relating to the "Reverse MTC effect" of the present invention is not limited to the case of being applied to the magnetic resonance imaging as described above, but it is not limited to Forsen & Hof.
ST (Satu as an NMR phenomenon reported by fman
ration transfer) method. FIG.
For two types of nuclear pools A and B that are in the relationship of chemical exchange and / or cross relaxation as shown in, by exciting one of the nuclear pools A with a narrow band RF pulse,
It is possible to improve the MR signal value of the one nucleus pool A by receiving the transfer of magnetization from the other nucleus pool B after the excitation. This improves the S / N ratio and improves the NM
Highly accurate spectroscopy using the R phenomenon is possible.

[0048]

As described above, the MR signal acquisition method, the magnetic resonance imaging method, and the magnetic resonance imaging apparatus of the present invention reduce the ST effect and the MTC effect as much as possible, and the spin of one target nuclear pool. Frequency selective excitation of only a narrow band RF pulse moves the magnetization from another pool of nuclei that are in a chemical exchange and / or cross relaxation and improves the MR signal value from the pool of nuclei of interest. Knowledge-based "Reverse MTC
Effect ". Therefore, the conventional ST method,
Exciting by frequency-selective pre-irradiation as in the MTC method, it is significantly different from that of observing a decrease in the signal value of another nuclear pool that has a chemical exchange and / or cross relaxation with it. , The S / N ratio is improved by improving the MR signal value, and high-quality MR imaging and highly accurate NMR spectroscopy analysis can be performed.

[Brief description of drawings]

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

FIG. 2 is a pulse sequence of a fast SE method executed in the same embodiment.

FIG. 3 is a waveform diagram of a narrow band 90 ° RF pulse.

FIG. 4 is a diagram illustrating an excitation width of a narrow band 90 ° RF pulse.

5 (a) and 5 (b) are views for explaining the magnetization state before and after the excitation related to the "Reverse MTC effect".

FIG. 6 is an experimental graph showing an example of the relationship between the frequency bandwidth of a narrow band RF pulse and the MR signal value.

FIG. 7 is an experimental graph showing an example of a relationship between a flip angle and a signal value.

FIG. 8 is a diagram illustrating “Reverse MTC effect” in ST method.

9A to 9C are views for explaining the conventional MTC effect together with the magnetization state.

10A and 10B are "Reverse" in the IR method.
The figure explaining "MTC effect".

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magnet 2 static magnetic field power supply 3x-3y gradient magnetic field coil 4 gradient magnetic field power supply 5 sequencer 6 controller 7 high frequency coil 8T transmitter 8R receiver 10 arithmetic unit 11 storage unit 13 input device

Claims (14)

[Claims] 1. A method of collecting a magnetic resonance signal for collecting an MR signal by a magnetic resonance phenomenon of at least two kinds of nuclear pools in a subject having a binding relationship by at least one of a chemical conversion phenomenon and a cross relaxation phenomenon. A step of frequency-selectively exciting a designated nucleus pool of the at least two types of nucleus pools with a high frequency pulse having a frequency bandwidth substantially matching the bandwidth on the frequency spectrum of the designated nucleus pool. And a step of collecting the MR signal of the designated nucleus pool reflecting the at least one phenomenon after the excitation, the method of collecting a magnetic resonance signal. 2. The method for collecting magnetic resonance signals according to claim 1, wherein the designated nucleus pool is a group of nuclei whose transverse relaxation (T ₂ ) time is longer than other nucleus pools. 3. The method for collecting magnetic resonance signals according to claim 2, wherein the designated nucleus pool is a collection of protons of free water in the subject. 4. The high-frequency pulse is a high-frequency pulse for tilting a nuclear spin flip angle to 90 ° or more.
A method for collecting a magnetic resonance signal as described. 5. The method of collecting magnetic resonance signals according to claim 2, wherein the high-frequency pulse is a 90 ° pulse. 6. The 90 ° pulse is a gradient field echo (F) used in magnetic resonance imaging.
E) method, fast gradient field echo (Fas
The excitation pulse of any pulse sequence of the t FE) method, the spin echo (SE) method, the fast spin echo (Fast SE) method, and the echo planar imaging (EPI) method applying these echo methods. 5
A method for collecting a magnetic resonance signal as described. 7. The selective excitation step and the signal acquisition step are a gradient field echo (FE) method,
Fast Gradient Field Echo (Fast F
E) method, spin echo (SE) method, fast spin echo (Fast SE) method, and an echo planar imaging (EPI) method applying these echo methods performed in any pulse sequence Item 5. A method for collecting magnetic resonance signals according to Item 5. 8. The method of collecting magnetic resonance signals according to claim 2, wherein the high frequency pulse is a 180 ° pulse. 9. The inversion pulse of any one of the inversion recovery (IR) method and the fast inversion recovery (Fast IR: FLAIR) method in the magnetic resonance imaging method, wherein the 180 ° pulse is an inversion pulse. Method for collecting magnetic resonance signals of the human. 10. The selective excitation step and the signal acquisition step include an inversion recovery (IR) method and a fast inversion recovery (Fast IR: FLA) method in a magnetic resonance imaging method.
9. The method of magnetic resonance signal acquisition according to claim 8, which is carried out in a pulse sequence of any one of the (IR) method. 11. The bandwidth of the high frequency pulse is 800H.
The magnetic resonance signal acquisition method according to any one of claims 1 to 10, which is z or less. 12. The method for collecting magnetic resonance signals according to claim 1, wherein the selective excitation step and the signal acquisition step are executed in a pulse sequence of a saturation transfer (ST) method in NMR spectroscopy. 13. An MR due to a magnetic resonance phenomenon of at least two kinds of nuclear pools in an analyte having a binding relationship due to at least one of a chemical conversion phenomenon and a cross relaxation phenomenon.
A method for collecting a magnetic resonance signal for collecting a signal, wherein a designated nuclear pool of the at least two types of nuclear pools has a frequency bandwidth that substantially matches a bandwidth on a frequency spectrum of the designated nuclear pool. A first high frequency pulse having a first frequency-selective excitation
And a second step of collecting MR signals of the designated nucleus pool reflecting the phenomenon of at least one after the first step, and the at least two kinds of nucleus pools of the designated nucleus pool. A third step of frequency-selectively exciting with a second high-frequency pulse having a frequency bandwidth wider than the bandwidth on the frequency spectrum, and the designation reflecting the at least one phenomenon after the third step A fourth step of collecting MR signals of the nuclear pool, and a fifth step of forming a contrast image for each excitation based on the MR signals acquired by the second and fourth steps. A characteristic magnetic resonance imaging method. 14. An MR according to a magnetic resonance phenomenon of a designated one kind of nuclear pool among at least two kinds of nuclear pools in a subject having a binding relationship by at least one of a chemical conversion phenomenon and a cross relaxation phenomenon. In a magnetic resonance imaging apparatus for collecting a signal, the designated nucleus pool, means for frequency-selectively exciting with a high-frequency pulse having a frequency bandwidth substantially matching the bandwidth on the frequency spectrum of the designated nucleus pool, A means for collecting MR signals of the designated nucleus pool reflecting the at least one phenomenon after the excitation, the magnetic resonance imaging apparatus.