KR20230041216A - Magnetic resonance imaging generating apparatus and method for acquiring blood vessel wall image - Google Patents

Abstract

The present invention relates to a magnetic resonance imaging generating device for obtaining a clearer blood vessel wall image. The magnetic resonance imaging generating device includes: a control unit for providing a pre-excitation pulse train of which excitation angle is adjusted according to the speed of a tissue of an object with respect to an MRI scanner; and an image processor for generating an enhanced image of a blood vessel wall from a magnetic resonance image signal acquired according to the pre-excitation pulse train. At this time, the control unit provides a pre-excitation pulse train including a B1 magnetic field and a gradient magnetic field designed such that the excitation angle decreases as the speed of the tissue decreases and the excitation angle increases as the speed of the tissue increases.

Description

MAGNETIC RESONANCE IMAGING GENERATING APPARATUS AND METHOD FOR ACQUIRING BLOOD VESSEL WALL IMAGE

The present invention relates to an apparatus for generating a magnetic resonance image and a method for generating a magnetic resonance image for obtaining an image of a blood vessel wall.

Medical imaging methods for diagnosing vascular diseases have mainly relied on lumen imaging. However, it has a limitation in that it cannot directly observe the fundamental pathological process starting from the blood vessel wall, so an imaging technique that directly depicts the blood vessel wall is required.

The most important image contrast condition in blood vessel wall imaging is to maximize the contrast-to-noise ratio between the blood vessel wall and the lumen by making the blood flow signal in the lumen as small as possible and the blood vessel wall signal around it as large as possible. . Magnetic resonance imaging is a medical imaging method that is in the spotlight because it does not expose to radiation, but gadolinium-based contrast agents commonly used in blood vessel imaging have a problem of causing a side effect called nephrogenic systemic fibrosis.

Accordingly, the present invention intends to provide an apparatus and method for generating a magnetic resonance image capable of acquiring a high-definition blood vessel wall image while maximally suppressing an image of blood flow without using a contrast medium in order to minimize side effects caused by the use of a contrast medium.

In the present invention, a preparatory excitation pulse sequence, which is one of the techniques used for generating a specific image contrast in magnetic resonance imaging, is used. The design of a general pre-applied pulse train is made under the assumption that human tissue does not move. In the present invention, in order to set the tissue velocity as a major input parameter, the effect of the blood flow velocity value on the application result is theoretically formulated to image the blood vessel wall. We propose a method for designing the applied pulse train to generate the contrast.

Republic of Korea Patent Registration No. 10-1334064 (Title of Invention: Motion Estimation Method and Apparatus in Vascular Image)

SUMMARY OF THE INVENTION The present invention is to solve the problems of the prior art, and an object of some embodiments of the present invention is to provide a method and apparatus for generating a magnetic resonance image capable of providing image contrast emphasizing a blood vessel wall.

However, the technical problem to be achieved by the present embodiment is not limited to the technical problem as described above, and other technical problems may exist.

As a technical means for achieving the above-mentioned technical problem, the magnetic resonance image generating apparatus according to the first aspect of the present invention provides a pre-applied pulse train whose excitation angle is adjusted according to the speed of the tissue of the object with respect to the MRI scanner. and an image processing unit generating a blood vessel wall enhancement image from a magnetic resonance image signal obtained according to the pre-applied pulse train. At this time, the control unit provides a pre-applied pulse train including a B1 magnetic field and a gradient magnetic field designed such that the application angle decreases as the tissue speed decreases and the application angle increases as the tissue speed increases.

In addition, a magnetic resonance image generating method using a magnetic resonance image generating apparatus according to a second aspect of the present invention includes providing a pre-applied pulse train whose application angle is adjusted according to the speed of a tissue of an object to an MRI scanner, and the pre-applied pulse train. and generating a blood vessel wall enhancement image from magnetic resonance image signals acquired according to the pulse train. At this time, the pre-applied pulse train includes a B1 magnetic field and a gradient magnetic field designed such that the application angle decreases as the speed of the tissue decreases and the application angle increases as the speed of the tissue increases.

According to the above-described means for solving the problems of the present invention, the present invention makes it possible to obtain an MRI image capable of clearly displaying a blood vessel wall while suppressing a signal in the lumen of a blood vessel. As such, it is possible to accurately diagnose vascular disease lesions by obtaining high-definition blood vessel wall images that can closely examine abnormal signs on the blood vessel wall without any risk of radiation exposure or side effects due to the use of a contrast agent.

1 is a block diagram showing an overall magnetic resonance image generating apparatus according to an embodiment of the present invention.
2 is a diagram showing an example of an image in which a blood vessel wall is emphasized, which is to be acquired by the present invention.
3 is a flowchart illustrating a method of generating a magnetic resonance image for acquiring a blood vessel wall image according to an embodiment of the present invention.
4 is a timing diagram illustrating a method for generating a magnetic resonance image according to an embodiment of the present invention.
5 is a diagram for explaining a Fourier transform equation to be used in designing a speed selection pre-applied pulse according to an embodiment of the present invention.
6 illustrates an example of a speed select pre-apply pulse applied according to an embodiment of the present invention.
FIG. 7 is a diagram illustrating weights accumulated in k-space of speed selection pre-apply pulses applied according to an embodiment of the present invention.
8 is a diagram illustrating Mxy and Mz values generated by a speed selection pre-applying pulse applied according to an embodiment of the present invention.
9 illustrates an example of a speed selection pre-apply pulse according to another embodiment of the present invention.
10 illustrates a blood vessel wall image obtained using a speed-selective pre-applied pulse train according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected" but also the case where it is "electrically connected" with another element interposed therebetween. . In addition, when a certain component is said to "include", this means that it may further include other components without excluding other components unless otherwise stated.

In the present specification, a "Magnetic Resonance Imaging (MRI) device" applies a magnetic field and non-ionizing radiation (radio frequency) to an object to obtain an image based on a physical principle called Nuclear Magnetic Resonance (NMR). Means the device that authorizes.

In addition, "image" or "image" refers to multi-dimensional data composed of discrete elements, a plurality of pixels in a 2-dimensional image and a plurality of voxels in a 3-dimensional image. means consisting of

Also, an “object” is an object to be photographed by a magnetic resonance imaging apparatus, and may include a human, an animal, or a part thereof. In addition, the object may include various organs such as the heart, brain, or blood vessel, or various types of phantoms.

In addition, a “user” may be a medical expert, such as a doctor, a nurse, a medical imaging expert, or a device repair technician, but is not limited thereto.

Also, "pulse sequence (or pulse train)" means a signal that is repeatedly applied in a magnetic resonance imaging apparatus. The pulse sequence may include a repetition time (TR) or an echo time (Time to Echo, TE) as a time parameter of the RF pulse.

Hereinafter, exemplary embodiments of a magnetic resonance imaging apparatus will be described with reference to the accompanying drawings.

1 is a block diagram showing an overall magnetic resonance image generating apparatus according to an embodiment of the present invention.

The magnetic resonance image generating apparatus 1 may include an MRI scanner 10, a signal processor 20, a controller 40, a monitoring unit 50, and an interface unit 60.

The MRI scanner 10 forms a magnetic field and generates a resonance phenomenon for atomic nuclei, and a magnetic resonance image is taken while an object is located inside the MRI scanner 10 . The MRI scanner 10 includes a main magnet 12, a gradient coil 14, an RF coil 16, and the like, through which a static magnetic field and a gradient magnetic field are formed, and an RF signal is radiated toward an object.

The main magnet 12, the gradient coil 14 and the RF coil 16 are arranged in the MRI scanner 10 according to a preset direction. An object is positioned on a table that can be inserted into the cylinder along a horizontal axis of the cylinder, and the object may be positioned inside the bore of the MRI scanner 10 as the table moves.

The main magnet 12 generates a static magnetic field that aligns directions of magnetic dipole moments of atomic nuclei included in the object in a certain direction.

The gradient coil 14 includes an X coil, a Y coil, and a Z coil that generate gradient magnetic fields in X-, Y-, and Z-axis directions orthogonal to each other. The gradient coil 14 induces a resonant frequency differently for each part of the object so that position information of each part of the object can be obtained.

The RF coil 16 may radiate an RF signal to the object and receive a magnetic resonance image signal emitted from the object. The RF coil 16 may output an RF signal having the same frequency as the frequency of the precession toward the atomic nuclei undergoing precession, and then receive a magnetic resonance image signal emitted from the object.

For example, the RF coil 16 generates an RF signal having a frequency corresponding to a corresponding atomic nucleus and applies it to an object in order to transition an atomic nucleus from a low energy state to a high energy state. Subsequently, when the RF coil 16 stops transmitting the RF signal, the atomic nucleus to which the electromagnetic wave has been applied transitions from a high energy state to a low energy state and emits an electromagnetic wave having a Larmore frequency, and the RF coil 16 The electromagnetic wave signal is received.

The RF coil 16 includes a transmitting RF coil for transmitting an RF signal having a radio frequency corresponding to the type of atomic nucleus and a receiving RF coil for receiving electromagnetic waves emitted from the atomic nucleus.

Also, the RF coil 16 may be fixed to the MRI scanner 10 or may be detachable. The detachable RF coil 16 may be implemented in the form of a head RF coil, a chest RF coil, a leg RF coil, a neck RF coil, a shoulder RF coil, a wrist RF coil, an ankle RF coil, etc. that can be coupled to a part of an object. can

The MRI scanner 10 may provide various types of information to a user or an object through a display, and may include an outer display 18 and an inner display (not shown).

The signal processing unit 20 may control a gradient magnetic field formed inside the MRI scanner 10 according to a predetermined MR pulse sequence (ie, a pulse train), and control transmission and reception of RF signals and magnetic resonance image signals.

The signal processing unit 20 may include a gradient magnetic field amplifier 22 , a switching unit 24 , an RF transmission unit 26 and an RF reception unit 28 .

The gradient amplifier 22 drives the gradient coil 14 included in the MRI scanner 10, and sends a pulse signal generating a gradient magnetic field under the control of the gradient magnetic field controller 44 to the gradient coil 14. supply to By controlling the pulse signal supplied from the gradient magnetic field amplifier 22 to the gradient coil 14, the gradient magnetic fields in the X-, Y-, and Z-axis directions can be synthesized.

The RF transmitter 26 drives the RF coil 16 by supplying an RF pulse to the RF coil 16 . The RF receiver 28 receives the magnetic resonance image signal transmitted after being received by the RF coil 16 .

The switching unit 24 may adjust transmission and reception directions of the RF signal and the magnetic resonance image signal. For example, an RF signal is irradiated to the object through the RF coil 16 during a transmission operation, and a magnetic resonance image signal from the object is received through the RF coil 16 during a reception operation. The switching operation of the switching unit 24 is controlled by a control signal from the RF controller 46.

The interface unit 30 may instruct the control unit 40 with pulse sequence information according to a user's manipulation and transmit a command for controlling the operation of the entire MRI system. The interface unit 30 may include an image processor 36 that processes the magnetic resonance image signal received from the RF receiver 38, an output unit 34, and an input unit 32.

The image processor 36 may process the magnetic resonance image signal received from the RF receiver 28 to generate MR image data of the object.

The image processor 36 applies various signal processes such as amplification, frequency conversion, phase detection, low frequency amplification, and filtering to the magnetic resonance image signal received by the RF receiver 28.

The image processing unit 36 may arrange digital data in, for example, k-space, and perform 2D or 3D Fourier transform on the data to reconstruct image data.

In addition, various signal processing applied to the magnetic resonance image signal by the image processing unit 36 may be performed in parallel. For example, a plurality of magnetic resonance image signals may be reconstructed into image data by applying signal processing in parallel to a plurality of magnetic resonance image signals received by multi-channel RF coils.

In addition, the image processing unit 36 generates an enhanced image of the vessel wall from the magnetic resonance image signal obtained according to the pre-applied pulse train, and details thereof will be described later.

The output unit 34 may output image data or reconstructed image data generated by the image processing unit 36 to a user. Also, the output unit 34 may output information necessary for a user to operate the MRI system, such as a user interface (UI), user information, or object information. The output unit 34 may include a speaker, a printer, or various image display means.

A user may input object information, parameter information, scan conditions, a pulse sequence, and information on image synthesis or difference calculation through the input unit 32 . The input unit 32 may include a keyboard, a mouse, a track ball, a voice recognition unit, a gesture recognition unit, a touch screen, and the like, and may include various other input devices within a range apparent to those skilled in the art.

The controller 40 includes a sequence controller 42 that controls a sequence of signals formed inside the MRI scanner 10 and a scanner controller 48 that controls the MRI scanner 10 and devices mounted on the MRI scanner 10. can include

The sequence controller 42 includes a gradient magnetic field controller 44 that controls the gradient amplifier 22, and an RF controller 46 that controls the RF transmitter 26, RF receiver 28, and switching unit 24. do. The sequence controller 42 may control the gradient amplifier 22, the RF transmitter 26, the RF receiver 28, and the switch 24 according to the pulse sequence received from the interface unit 30. The pulse sequence includes all information required to control the gradient magnetic field amplifier 22, the RF transmitter 26, the RF receiver 28, and the switching unit 24, and is, for example, a pulse applied to the gradient coil 14. (pulse) signal intensity, application time, application timing (timing) information, etc. may be included.

The control unit 40 provides the MRI scanner 10 with a pre-excitation pulse train whose excitation angle is adjusted according to the speed of the tissue of the object. At this time, the pre-applied pulse train is characterized in that it includes a B1 magnetic field and a gradient magnetic field designed so that the application angle decreases as the speed of the tissue decreases and the application angle increases as the speed of the tissue increases. Details thereof will be described later.

The monitoring unit 50 monitors or controls the MRI scanner 10 or devices mounted on the MRI scanner 10 . The monitoring unit 50 may include a system monitoring unit 52, an object monitoring unit 54, a table control unit 56, and a display control unit 58.

The system monitoring unit 52 monitors the state of the static magnetic field, the state of the gradient magnetic field, the state of the RF signal, the state of the RF coil, the state of the table, the state of the device for measuring the body information of the object, the state of the power supply, the state of the heat exchanger, You can monitor and control the condition of the compressor.

The object monitoring unit 54 monitors the state of the object, such as a camera for capturing the movement or position of the object, a respiration monitor for measuring respiration of the object, an ECG meter for measuring the electrocardiogram of the object, or a body temperature for measuring the object. It may include a body temperature measuring device.

The table controller 56 controls the movement of the table on which the object is located. The table control unit 56 can control movement of the table in synchronization with a sequence control signal output from the sequence control unit 42 . For example, in moving imaging of an object, the table controller 56 may move the table according to sequence control, thereby enabling the object to have a larger FOV than the field of view (FOV) of the MRI scanner. can be filmed.

The display control unit 58 turns on/off displays located outside and inside the MRI scanner 10 or controls a screen to be output to the display. In addition, when a speaker is located inside or outside the MRI scanner 10, the display controller 58 may control on/off of the speaker or sound to be output through the speaker.

The MRI scanner 10, the RF coil 16, the signal processing unit 20, the monitoring unit 50, the control unit 40, and the interface unit 30 may be connected wirelessly or wired to each other, and when connected wirelessly, each other. It may further include a device (not shown) for synchronizing a clock between clocks.

The magnetic resonance image generating apparatus 1 according to an embodiment of the present invention has a configuration of the control unit 40 and the image processing unit 36. In this case, the image processing unit 36 may perform a magnetic resonance image restoration operation to be described later using a memory and a processor mounted in the computing device. That is, a program for restoring a magnetic resonance image from an MRI signal obtained from an object is stored in the memory. Memory collectively refers to a non-volatile storage device that continuously retains stored information even when power is not supplied, and a volatile storage device that requires power to maintain stored information.

2 is a diagram showing an example of an image in which a blood vessel wall is emphasized, which is to be acquired by the present invention.

As shown on the left side of FIG. 2 , medical imaging methods for diagnosing vascular diseases have mainly relied on lumen imaging, but this has a limitation in that it cannot directly observe a fundamental pathological process starting from a blood vessel wall. In order to solve this problem, in the present invention, as shown on the right, the blood flow part is treated with black blood, which is displayed in black, and the blood vessel wall signal is maximized to provide an image with very high image contrast between the blood vessel wall and the lumen. do.

3 is a flowchart illustrating a method for generating a magnetic resonance image for acquiring a blood vessel wall image according to an embodiment of the present invention, and FIG. 4 is a timing diagram illustrating a method for generating a magnetic resonance image according to an embodiment of the present invention.

First, the control unit 40 of the magnetic resonance image generating apparatus 1 provides a pre-excitation pulse train whose excitation angle or bending angle is adjusted according to the speed of the tissue of the object to the MRI scanner 10 (S310). .

At this time, the pre-applied pulse train includes a B1 magnetic field and a gradient magnetic field designed such that the applied angle decreases as the speed of the tissue decreases and the applied angle increases as the speed of the tissue increases. As a result, the vertical component of the magnetic spin of the tissue with low velocity is high, and the vertical component of magnetic spin of the tissue with high velocity is low.

Next, a blood vessel wall enhancement image having image contrast generated from the pre-applied pulse train through a 3D image signal acquisition process is generated (S320).

As shown in FIG. 4, providing a speed-selective pre-applied pulse train (S310), elapse of a predetermined delay time (T1), providing a fat saturation suppression pulse, segmented 3D magnetic resonance imaging signal Obtaining (S320) is repeatedly performed, and based on this, an enhanced image of the vessel wall is generated.

Now, the pre-applied pulse train in which the application angle is adjusted according to the tissue speed, which is the main feature of the present invention, will be described in more detail.

First, in MRI, the process of rotating the magnetic spin of a human tissue initially vertically (ie, z-direction) about a horizontal axis is called excitation, and the horizontal component of the magnetic spin generated after excitation (normally M _xy ) expressed as a function of the spatial position r and the velocity v is shown in Equation 1 below.

[Equation 1]

It is expressed as the Fourier transform of the B1 magnetic field applied on the multidimensional k-space composed of _{k r} (Fourier variable of r) and k _v (Fourier variable of v), and the weight of the B1 magnetic field on this k-space is our target Design the B1 magnetic field and the gradient field so that the inverse Fourier transform of the M _xy profile of

k _r is proportional to the zeroth moment of the gradient magnetic field (G), and k _v is proportional to the first moment of the gradient magnetic field.

When used for pre-applied pulses, the M _z component generated as a result of the application is important, and the relational expression with the M _xy component is expressed by Equation 2 as follows.

[Equation 2]

That is, when M _z increases, M _xy decreases, and when M _z decreases, M _xy increases.

In the present invention, for the design of the pre-applied pulse train, the Fourier transform relationship between x(t) and X(w) is applied to the v and k _v domains of Equation 1 to design.

5 is a diagram for explaining a Fourier transform equation to be used in designing a speed selection pre-applied pulse according to an embodiment of the present invention.

As shown in FIG. 5, when x(t) formed of a square wave is Fourier transformed, a Fourier transform equation having (-1/n) as a coefficient is derived. At this time, n represents an odd integer.

As such, the B1 magnetic field and the gradient magnetic field waveform are designed so that a relative weight of (1/n) is applied to the kv axis, an example of which is shown in FIG. 7 .

6 illustrates an example of a speed select pre-apply pulse applied according to an embodiment of the present invention.

As shown, the gradient magnetic field is provided as a bipolar gradient magnetic field pulse, and the B1 magnetic field is provided as a pulse to which an amplitude of (−1/n, where n is an odd integer) is applied between pulses of the bipolar gradient magnetic field.

Meanwhile, FIG. 7 shows the meaning of the pre-applied pulse train shown in FIG. 6 in terms of k-space expressed in Equation 1.

FIG. 7 is a diagram illustrating weights accumulated in k-space of speed selection pre-apply pulses applied according to an embodiment of the present invention.

Since each bipolar gradient magnetic field pulse has zero width, only kv is changed in the form of (-1/n) without changing kr, so there is no applied change in the r direction and only in the v direction, x (t in FIG. 6 ), an application in the form of a square wave, expressed as That is, selective application occurs only in velocity without being spatially selective, and accordingly, it is possible to selectively apply the blood vessel wall having zero velocity, which is the object of the present invention.

8 is a diagram illustrating Mxy and Mz values generated by a speed selection pre-applying pulse applied according to an embodiment of the present invention.

As shown, the absolute value of Mxy has the same characteristics as the absolute value of x(t) in FIG. 5, and Mz is obtained by the equation shown in FIG. 5, when |Mxy| is maximum, Mz is minimum , and when |Mxy| is minimum, Mz becomes maximum and has a relationship. Accordingly, a high signal is obtained for a tissue having a velocity of 0, such as a blood vessel wall, and a signal close to 0 is obtained for a tissue having a high moving velocity, such as blood flow.

In other words, in the pre-applied pulse train of the present invention, when the speed of the tissue is low, the applied angle becomes small and the magnitude (Mz) of the longitudinal component is increased, and when the speed of the tissue is high, the applied angle is increased to increase the Reduce the size (Mz).

Meanwhile, while applying such a pre-applied pulse train, a modified pre-applied pulse train may be considered in consideration of an error in the magnetic field in the MRI scanner.

9 illustrates an example of a speed selection pre-apply pulse according to another embodiment of the present invention.

As shown, it is characterized by the addition of a refocusing pulse for 180 degree rotation in the B1 magnetic field.

The gradient magnetic field is provided in the form of repeating unipolar gradient magnetic field pulses and bipolar gradient magnetic field pulses, and the B1 magnetic field is provided between the unipolar gradient magnetic field pulse and the bipolar gradient magnetic field pulse and every two refocusing pulses ( -1/n) size applied pulses.

10 illustrates a blood vessel wall image obtained using a velocity-selective pre-applied pulse train according to an embodiment of the present invention.

The blood vessel walls of the femoral artery and femoral vein in the thigh are clearly shown, and it can be confirmed that the blood flow signal inside the vessel wall is well suppressed.

Meanwhile, the magnetic resonance image generation method according to an embodiment of the present invention may be implemented in the form of a recording medium including instructions executable by a computer, such as program modules executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. Also, computer readable media may include all computer storage media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data.

The above description of the present invention is for illustrative purposes, and those skilled in the art can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be construed as being included in the scope of the present invention. do.

1: magnetic resonance image generating device
10: MRI scanner
20: signal processing unit
30: interface unit
36: image processing unit
40: control unit
50: monitoring unit

Claims (11)

In the magnetic resonance image generating device,
A control unit providing a pre-excitation pulse train whose excitation angle is adjusted according to the speed of a tissue of an object with respect to the MRI scanner; and
An image processing unit for generating a blood vessel wall enhancement image from magnetic resonance image signals collected after application of the pre-applied pulse train,
Wherein the control unit provides a pre-applied pulse train including a B1 magnetic field and a gradient magnetic field designed such that the applied angle decreases as the speed of the tissue decreases and the applied angle increases as the speed of the tissue increases. Device. According to claim 1,
The control unit is a pre-applied pulse train including a B1 magnetic field and a gradient magnetic field designed to increase the magnitude of the longitudinal component of the magnetic spin as the speed of the tissue is lower and to decrease the magnitude of the longitudinal component of the magnetic spin as the velocity of the tissue is higher To provide a magnetic resonance image generating device. According to claim 1,
Wherein the control unit provides a pre-applied pulse train including a B1 magnetic field and a gradient magnetic field designed such that the applied angle becomes smaller for a blood vessel wall having a low tissue velocity and the applied angle becomes larger for a blood flow having a high tissue velocity, Magnetic resonance imaging device. According to claim 1,
The gradient magnetic field is composed of a plurality of bipolar pulses,
The B1 magnetic field is provided as pulses having a magnitude of (-1/n) applied between the bipolar gradient magnetic field pulses. According to claim 1,
The gradient magnetic field is provided in the form of repeating unipolar gradient magnetic field pulses and bipolar gradient magnetic field pulses,
The B1 magnetic field is provided as a refocusing pulse provided between the pulse of the unipolar gradient magnetic field and the pulse of the bipolar gradient magnetic field and a pulse having a size of (-1/n) applied to every two refocusing pulses. Magnetic resonance image generating device. A magnetic resonance image generating method using a magnetic resonance image generating apparatus,
providing a pre-excitation pulse train whose excitation angle is adjusted according to the speed of the tissue of the object to the MRI scanner; and
generating a blood vessel wall enhancement image from magnetic resonance image signals collected after application of the pre-applied pulse train;
Wherein the pre-applied pulse train includes a B1 magnetic field and a gradient magnetic field designed such that the application angle decreases as the tissue speed decreases and the application angle increases as the tissue speed increases. According to claim 6,
The pre-applied pulse train includes a B1 magnetic field and a gradient magnetic field designed to increase the magnitude of the longitudinal component of the magnetic spin as the speed of the tissue decreases and decrease the magnitude of the longitudinal component of the magnetic spin as the velocity of the tissue increases. A magnetic resonance image generating method comprising an applied pulse train. According to claim 6,
The pre-applied pulse train includes a pre-applied pulse train including a B1 magnetic field and a gradient magnetic field designed such that the applied angle becomes smaller for a blood vessel wall with a low tissue velocity and the applied angle becomes larger for a blood flow with a high tissue velocity. Phosphorus, magnetic resonance imaging method. According to claim 6,
The gradient magnetic field is composed of a plurality of bipolar gradient magnetic field pulses,
Wherein the B1 magnetic field is provided as a pulse having a magnitude of (-1/n) applied between pulses of the bipolar gradient magnetic field. According to claim 6,
The gradient magnetic field is provided in the form of repeating unipolar gradient magnetic field pulses and bipolar gradient magnetic field pulses,
The B1 magnetic field is provided as a refocusing pulse provided between the pulse of the unipolar gradient magnetic field and the pulse of the bipolar gradient magnetic field and a pulse having a size of (-1/n) applied to every two refocusing pulses. Magnetic resonance image How to create. A computer readable recording medium on which a computer program for performing the method of any one of claims 6 to 10 is recorded.

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