JP2005021322A - Magnetic resonance imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic resonance imaging apparatus for highly sensitively receiving magnetic resonance signals from the neck as well as the head of a subject. <P>SOLUTION: The apparatus comprises a head RF coil 110 with a large loop diameter and a small RF coil 116 with a small loop diameter, disposed near the neck of the subject 1, both of which are disposed on the subject 1, and the apparatus allows an operator to freely obtain image information on the whole head and highly sensitive detailed image information on the neck of the subject. Accordingly, a thick neurovascular system over the whole head can be generally described, and the neurovascular system near the neck can be limitedly and highly sensitively displayed. As a result, a detailed examination around the neck, organically connected to the general neurovascular information on the head, can be performed at the same time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic resonance imaging apparatus that performs imaging using a plurality of RF coils.
[0002]
[Prior art]
In recent years, in imaging using a magnetic resonance imaging apparatus of the head, finer image information is being required over the entire head. In particular, when imaging the nerve or vascular system of the head, a high-sensitivity RF coil is required to achieve high resolution. As the function of the magnetic resonance imaging apparatus is improved, it is becoming possible to increase the number of channels for simultaneously receiving magnetic resonance signals from a plurality of RF coils.
[0003]
From such a demand, instead of the BirdCage type that can image the entire head with uniform sensitivity, a plurality of loop coils are arranged, and a phased array of image information obtained from these loop coils ( A neurovascular coil is used for performing phased array synthesis (see, for example, Patent Document 1). According to this neurovascular coil, high-sensitivity image information can be acquired in the region of interest of the head, and a thick blood vessel or the like can be imaged.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-135420, (pages 5-8, FIGS. 2-5)
[0005]
[Problems to be solved by the invention]
However, according to the above-described prior art, it has been difficult to acquire fine image information of a fine blood vessel, particularly a carotid artery existing in the neck of the subject. That is, in the neurovascular coil, each loop constituting the coil images a relatively wide area of the head, so the loop diameter of each loop needs to be approximately the same as the size of the head, It was insufficient to obtain image information having the sensitivity necessary for rendering fine blood vessels.
[0006]
In particular, the subject's neck is located at the end of the coil where the sensitivity is low because the subject's head is located at the center of the neurovascular coil, and the subject's neck is stretched laterally. Because it has a shoulder to be taken out, it is difficult to create a neurovascular coil that continuously covers the neck from the head, and it is a factor that image information with sufficient sensitivity is not acquired in rendering the neck Yes.
[0007]
For these reasons, it is important how to realize a magnetic resonance imaging apparatus that receives magnetic resonance signals from the neck in addition to the head of the subject with high sensitivity.
[0008]
The present invention has been made to solve the above-described problems caused by the prior art, and provides a magnetic resonance imaging apparatus that receives a magnetic resonance signal from the neck in addition to the head of the subject with high sensitivity. With the goal.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems and achieve the object, the magnetic resonance imaging apparatus according to the first aspect of the invention includes a plurality of large loops having a loop diameter substantially equal to the head of the subject. A head RF coil, a small RF coil composed of one or a plurality of small loops having a loop diameter not exceeding the neck thickness of the subject, and the small RF coil are arranged near the neck of the subject. And a control processing means for receiving a magnetic resonance signal from the subject and reconstructing tomographic image information from the magnetic resonance signal using the head RF coil and the small RF coil. It is characterized by providing.
[0010]
According to the first aspect of the invention, the head RF coil composed of a plurality of large loops has a loop diameter substantially equal to that of the subject's head, and is a small RF composed of one or a plurality of small loops. The coil has a loop diameter that does not exceed the thickness of the neck of the subject. The small RF coil is disposed in the vicinity of the neck of the subject by the disposing means, and the head RF coil and the coil are disposed by the control processing means. A small RF coil is used to receive magnetic resonance signals from the subject, and tomographic image information is reconstructed from these magnetic resonance signals, so that image information over the entire head and high sensitivity near the neck are detailed. Information can be obtained freely by the operator, and disease information obtained from image information over the entire head and detailed image information in the vicinity of the cervix can be obtained simultaneously and in a relevant manner. To do Kill.
[0011]
The magnetic resonance imaging apparatus according to the second aspect of the present invention is configured such that when the head RF coil and the small RF coil are formed of a rectangular large loop and a small loop, the diagonal length of the rectangle is looped. It is characterized by a diameter.
[0012]
According to the invention of the second aspect, the head RF coil and the small RF coil have sensitivity up to the depth of the length in the major axis direction orthogonal to the rectangular surface.
[0013]
The magnetic resonance imaging apparatus according to the invention of the third aspect is characterized in that the maximum length of a cross section of the head and the neck perpendicular to the midline of the subject is a size and a thickness. And
[0014]
According to the invention of the third aspect, by setting the loop diameters of the head RF coil and the small RF coil to this size and thickness, the entire cross section orthogonal to the median line of the head and neck can be obtained with sensitivity. Can be an area.
[0015]
In the magnetic resonance imaging apparatus according to the fourth aspect of the invention, the head RF coil is such that the large loop surface surrounded by the large loop partially overlaps between the adjacent large loops. .
[0016]
According to the fourth aspect of the invention, magnetic coupling between adjacent large loops can be prevented.
[0017]
In the magnetic resonance imaging apparatus according to the fifth aspect of the invention, when the small RF coil includes a plurality of adjacent small loops, the small loop surfaces surrounded by the small loops partially overlap. Features.
[0018]
According to the fifth aspect of the invention, magnetic coupling between adjacent small loops can be prevented.
[0019]
Further, in the magnetic resonance imaging apparatus according to the invention of the sixth aspect, the disposing means comprises a fixing means for fixing the small loop coil in an arbitrary space near the neck with mobility. Features.
[0020]
According to the sixth aspect of the invention, the disposing means fixes the small loop coil movably in an arbitrary space near the neck by the fixing means. A small loop coil can be arranged at an optimal imaging position near the neck.
[0021]
The magnetic resonance imaging apparatus according to the seventh aspect of the invention is characterized in that the disposing means includes a pair of fixing means at symmetrical positions sandwiching the neck.
[0022]
According to the seventh aspect of the invention, since the disposing means has the pair of fixing means at the symmetrical positions sandwiching the neck, the arteriovenous veins present at the symmetrical positions within the neck are It can be drawn using a small coil.
[0023]
The magnetic resonance imaging apparatus according to the invention of the eighth aspect is common to the two large loops in that the head RF coil overlaps two large loops constituting the partially overlapping large loop surface. It is a grounding point to be used.
[0024]
According to the eighth aspect of the invention, the capacitive coupling that occurs at the point where the two loops overlap can be prevented, and the head RF coil can be operated stably.
[0025]
Further, in the magnetic resonance imaging apparatus according to the ninth aspect of the invention, the head RF coil is composed of a plurality of large loops having the same shape in which the large loop surfaces are combined to form a cylindrical shape, and the large loop is the cylinder. It is characterized by being a cylindrical coil arrange | positioned at equal intervals on the circumference which makes a circular cross section of a shape.
[0026]
According to the ninth aspect of the invention, the head RF coil has a cylindrical shape, and the head is easily arranged at a position where the magnetic field distribution at the center of the head RF coil is uniform and highly sensitive. Good image information can be acquired.
[0027]
In the magnetic resonance imaging apparatus according to the tenth aspect of the invention, when the cylindrical coil is composed of an even number of four or more large loops, the magnetic resonance imaging apparatus is divided into two adjacent large loops, The grounding point is provided for each grouping.
[0028]
According to the tenth aspect of the invention, it is possible to perform grounding with high stability for all large loops.
[0029]
The magnetic resonance imaging apparatus according to an eleventh aspect of the invention is parallel to the base plate when the cylindrical coil is placed on a base plate parallel to the long axis direction forming the cylindrical tube. Two grounding points are provided in one plane.
[0030]
According to the eleventh aspect of the invention, the cylindrical coil has a grounding point at a symmetrical position of the subject's head, and is small when the small RF coil is disposed at the symmetrical position. It is possible to measure the high stability of the contact point including the RF coil.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of a magnetic resonance imaging apparatus according to the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited thereby.
[0032]
First, the overall configuration of a magnetic resonance imaging apparatus according to an embodiment of the present invention will be described. FIG. 1 is a block diagram showing the overall configuration of a magnetic resonance imaging apparatus according to an embodiment of the present invention. In FIG. 1, the magnetic resonance imaging apparatus includes a magnet system 100, a gradient driving unit 130, a transmission driving unit 140, a data collecting unit 150, and a control processing unit 199.
[0033]
The magnet system 100 includes a main magnetic field coil unit 102, a gradient coil unit 106, a transmission coil unit 108, a head RF coil 110, and a small RF coil 116. Except for the small RF coil 116, each of these coil portions has a substantially cylindrical shape and is arranged coaxially with each other. A subject 1 to be imaged is placed on a cradle 120 serving as a base plate in a substantially cylindrical internal space (bore) of the magnet system 100, and is carried in and out by a conveying means (not shown).
[0034]
The main magnetic field coil unit 102 forms a static magnetic field in the internal space of the magnet system 100. The direction of the static magnetic field is generally parallel to the direction of the body axis of the subject 1 and forms a so-called horizontal magnetic field. The main magnetic field coil unit 102 is configured using, for example, a superconducting coil. In addition, it can also comprise using not only a superconductive coil but a normal conductive coil.
[0035]
The gradient coil unit 106 generates three gradient magnetic fields for giving gradients to the static magnetic field strength in the directions of three axes perpendicular to each other, that is, the slice axis, the phase axis, and the frequency axis.
[0036]
The transmission coil unit 108 forms a high-frequency magnetic field that excites magnetic resonance in the body of the subject 1 when the subject 1 is placed in the static magnetic field space. In addition, the head RF coil 110 and the small RF coil 116 are placed on the cradle 120, and are arranged in the center of the magnet system 100 together with the subject 1. The head RF coil 110 and the small RF coil 116 receive magnetic resonance signals excited in the body of the subject 1 using the transmission coil unit 108.
[0037]
The gradient driving unit 130 is connected to the gradient coil unit 106 and gives a drive signal to the gradient coil unit 106 to generate a gradient magnetic field. The gradient drive unit 130 has three systems of drive circuits (not shown) corresponding to the three systems of gradient coils in the gradient coil unit 106.
[0038]
The transmission drive unit 140 is connected to the transmission coil unit 108, gives a drive signal to the transmission coil unit 108, and transmits an RF pulse to the subject 1. The transmission coil unit 108 forms an RF magnetic field from the transmitted RF pulse in the central part of the magnet system 100, and puts the subject 1 in an excited state of magnetic resonance.
[0039]
The data acquisition unit 150 is connected to the head RF coil 110 and the small RF coil 116, and takes in analog magnetic resonance signals received by the head RF coil 110 and the small RF coil 116 by sampling. It is collected as digital data.
[0040]
The control processing unit 199 includes a scan controller unit 160, a data processing unit 170, a display unit 180, and an operation unit 190. The scan controller unit 160 is connected to the gradient driving unit 130, the transmission driving unit 140, and the data collecting unit 150, and serves as a transmission / reception control unit that controls the gradient driving unit 130 to the data collecting unit 150 to perform shooting.
[0041]
The data processing unit 170 is connected to the output side of the data collection unit 150 and receives data collected by the data collection unit 150. The data processing unit 170 is configured using, for example, a computer and has a memory (not shown). In this memory, programs used in the data processing unit 170 and various data are stored.
[0042]
The data processing unit 170 is also connected to the scan controller unit 160 and is superordinate to the scan controller unit 160. Acquisition of tomographic image information according to the present apparatus is realized by executing a pulse sequence (Pulse Sequence), which is a program stored in the memory of the data processing unit 170, by the scan controller unit 160.
[0043]
The data processing unit 170 stores the data collected by the data collection unit 150 in a memory. A data space is formed in the memory. This data space constitutes a two-dimensional Fourier space. The data processing unit 170 reconstructs image information of the subject 1 by performing two-dimensional inverse Fourier transform on the data in the two-dimensional Fourier space.
[0044]
The display unit 180 and the operation unit 190 are connected to the data processing unit 170. Here, the display unit 180 is configured by using a graphic display such as an LCD (Liquid Crystal Display), and the operation unit 190 is configured by a keyboard having a pointing device. The
[0045]
The display unit 180 displays the reconstructed image and various information output from the data processing unit 170. The operation unit 190 inputs various commands and information to the data processing unit 170 through operations by the operator. An operator operates the apparatus interactively through the display unit 180 and the operation unit 190.
[0046]
Next, specific configurations of the head RF coil 110 and the small RF coil 116 shown in FIG. 1 will be described with reference to FIG. FIG. 2 is an example of a head RF coil 110 composed of four rectangular large loop coils 210 to 240 and a small RF coil 116 composed of four rectangular small loop coils 250 to 280. The head RF coil 110 surrounds the head of the subject 1 (indicated by the dotted line in FIG. 2) such that the coil surfaces of the large loop coils 210 and 230 and the coil surfaces of the large loop coils 220 and 240 face each other. It is disposed on the cylindrical surface. The small RF coil 116 is disposed so that the coil surface formed by the small loop coils 250 and 260 and the coil surface formed by the small loop coils 270 and 280 are generally opposed to each other and sandwich the neck of the subject 1. Established.
[0047]
The large loop coils 210 to 240 of the head RF coil 110 place the subject 1 in a ring-shaped cross section constituted by these coils. Here, in each of the rectangular large loop coils 210 to 240, the adjacent coils and the coil surfaces overlap each other by approximately 10%. As a result, the magnetic coupling generated between adjacent coils is eliminated, the decrease in the Q value of the single coil is suppressed, and the S / N ratio of the received magnetic resonance signal is increased. Similarly, the small loop coils 250 to 280 of the small RF coil 116 also have a coil surface that overlaps by approximately 10% between the small loop coils 250 and 260 and between the small loop coils 270 and 280, and between the adjacent coils. The generated magnetic coupling is eliminated, the decrease in the Q value of the coil unit is suppressed, and the S / N ratio of the received magnetic resonance signal is increased.
[0048]
The large loop coils 210 to 240 and the small loop coils 250 to 280 can be received by a low input impedance preamplifier that forms a parallel resonance circuit (not shown). These preamplifiers are connected to the data collection unit 150 via a cable, and the resonance frequency of the parallel resonance circuit is set to the resonance frequency when magnetic coupling is generated with the opposing coil. Accordingly, the parallel resonant circuit is in a high impedance state at the resonant frequency, and the magnetic coupling between the opposing coils can be eliminated.
[0049]
The loop diameter, which is the length of one side of the rectangular coil, determines the imaging area and sensitivity of the coil. Increasing the loop diameter secures a wide and deep imaging area, while lowering the sensitivity of the imaging area. Also, by reducing the loop diameter, the sensitivity of the imaging region increases while the imaging region becomes narrow and shallow.
[0050]
Here, each loop diameter of the large loop coils 210 to 240 forming the head RF coil 110 is an optimal shape for rendering the entire head with high sensitivity. In the head RF coil 110, in order to widen and deepen the sensitivity region in consideration of imaging a deep part of the head of the subject 1, the loop diameter is approximately the size of the head. The loop diameter of the head RF coil 110 is approximately 25 cm.
[0051]
On the other hand, when imaging a local region close to the body surface of the subject 1, highly sensitive image information with less noise can be acquired by using a coil with a small loop diameter. The loop diameters of the small loop coils 250 to 280 forming the small RF coil 116 are optimally shaped to depict the jugular vein or the carotid artery existing in the neck. Here, the small RF coil 116 is selected to have a small loop diameter capable of performing imaging of the jugular vein or the carotid artery portion existing relatively near the body surface of the neck with high sensitivity. The loop diameter of the small RF coil 116 is approximately 10 cm.
[0052]
Subsequently, the arrangement of the head RF coil 110 and the small RF coil 116 illustrated in FIG. 2 on the cradle 120 is shown in FIG. On the cradle 120 that forms the base plate, the headrest 123 that positions and fixes the head of the subject 1, the arms 121 and 122 that form the arrangement means of the small RF coil 116, and the tips of the arms 121 and 122 are fixed. There is a small RF coil 116 and a head RF coil 110. And the small RF coil 116 is arrange | positioned using the arms 121 and 122 in the position which pinches | interposes the headrest 123. FIG.
[0053]
The head RF coil 110 is slidably fixed on the cradle 120, and after the head of the subject 1 is placed on the headrest 123, the head RF coil 110 is slid in the direction of the headrest 123 so that the head of the subject 1 is the head. The RF coil 110 is fixed at a location located at the center.
[0054]
The arms 121 and 122 that constitute the disposing means are fixed to any of the headrest 123, the cradle 120, or the head RF coil 110, and are configured using a plastic pipe that can be bent and also serves as a fixing means. The small RF coil 116 fixed to the distal ends of the arms 121 and 122 is disposed at an optimal imaging position located near the neck of the subject 1 placed on the headrest 123 by the bendable arms 121 and 122. The
[0055]
Next, a specific configuration of the data collection unit 150 illustrated in FIG. 1 will be described with reference to FIG. The data collection unit 150 receives magnetic resonance signals received by the head RF coil 110 and the small RF coil 116. Magnetic resonance signals input from the large loop coils 210 to 240 and the small loop coils 250 to 280 are received and amplified by the reception units 321 to 328 and sent to the detection unit 330. In the detection unit 330, detection is performed, and the resonance frequency component of the magnetic resonance signal is shifted to the low frequency side. Thereafter, an A / D (analog to digital) conversion unit 340 converts the analog signal into a digital signal and transfers the signal to the data processing unit 170.
[0056]
In addition, the receiving units 321 to 328 are individually selected and operated by a control signal from the scan controller unit 160, for example, the large loop coils 210 to 240 and the small loop coils 250 to 280 are all operated simultaneously, Any one of the large loop coils 210 to 240 or the small loop coils 250 to 280 can be operated, or only one of the small loop coils 250 to 280 can be operated. Note that the coil selection information to the scan controller unit 160 is made from the data processing unit 170.
[0057]
Next, imaging using the head RF coil 110 and the small RF coil 116 shown in FIG. 2 will be described with reference to FIG. FIG. 5 is a flowchart showing imaging of the head RF coil 110 and the small RF coil 116 shown in FIG.
[0058]
First, the operator places the head RF coil 110 and the small RF coil 116 on the cradle 120, and places these coils at the imaging region of the subject 1, that is, at the optimal imaging positions of the head and neck (step S501). ). In particular, the small RF coil 116 is arranged at an optimum imaging position located near the neck of the subject 1 using the arms 121 and 122. Then, the subject 1 is placed in the center of the magnet system 100 together with the cradle 120. When the installation of the subject 1 on the magnet system 100 is completed, the operator performs a prescan in accordance with an instruction from the operation unit 190 (step S502). In this prescan, adjustment of the magnetic resonance frequency, optimization of the transmission power (power) output from the transmission drive unit 140, gain adjustment of the amplifiers of the reception units 321 to 328 of the data collection unit 150, and the like are performed.
[0059]
Thereafter, the operator performs a positioning scan (step S503). Based on the tomographic image information obtained on the display unit 180 using this positioning scan, the operator determines a site for imaging the subject 1 on the display unit 180 using, for example, a pointing device. Then, selection setting of a coil and a pulse sequence that seems to be optimal for the imaging purpose is performed (step S504). Here, the type of pulse sequence, for example, the spin echo method or the gradient echo method is selected, and the large loop coils 210 to 240 or the small loop coils 250 to 280 are selected. . Then, detailed settings such as the repetition time and echo time of the selected pulse sequence are input from the operation unit 190.
[0060]
Thereafter, the operator scans and collects image information (step S505). The acquired image information is subjected to image reconstruction such as phase correction, two-dimensional inverse Fourier transform, and a sum of squares of a plurality of image information (step S507), and the reconstructed tomographic image information is displayed on the display unit 180. (Step S507).
[0061]
Thereafter, the operator determines whether to perform the inspection again from the displayed tomographic image information (step S508). In this determination, for example, when plaque that is a lump of waste accumulated in the blood vessel is detected from the displayed image information of the head, it is determined whether or not the plaque is derived from the carotid artery. The test is performed again to confirm.
[0062]
When the operator performs the inspection again (Yes at Step S508), the operator positions the imaging position based on the displayed image information (Step S509), and proceeds to selection of the coil and pulse sequence at Step S504. . Here, for example, when it is determined whether or not the detected plaque is derived from the carotid artery, the small loop coils 250 to 280 of the small RF coil 116 located in the vicinity of the carotid artery, or one of these coils. The carotid artery image information with high sensitivity is acquired in more detail, and the above-described determination is performed.
[0063]
In addition, it is possible to select the head RF coil 110 and the small RF coil 116 differently based on the image information acquired in steps S504 to S507 and the reexamination steps S508 to S509, thereby improving the accuracy and usefulness. High image information can be acquired.
[0064]
Note that when the operator does not detect plaque or the like from the image information and does not need to perform the inspection again (No at step S508), the operator ends the process.
[0065]
As described above, in the present embodiment, the head RF coil 110 having a large loop diameter and the small RF coil 116 having a small loop diameter disposed near the neck of the subject 1 are both disposed on the subject 1. Since the operator can freely acquire image information over the entire head and detailed image information with high sensitivity in the vicinity of the neck, the entire neurovascular system over the entire head is depicted. In addition, with a small RF coil, the neurovascular system near the neck is limited but highly sensitive, and a detailed examination of the vicinity of the neck that is organically linked to the overall neurovascular information of the head At the same time, it can be performed efficiently.
[0066]
In the present embodiment, an example using a horizontal magnetic field type magnetic resonance imaging apparatus has been described. However, the present embodiment can be similarly realized by using a vertical magnetic field type magnetic resonance imaging apparatus.
[0067]
【The invention's effect】
As described above, according to the present invention, the head RF coil composed of a plurality of large loops has a loop diameter approximately equal to that of the head of the subject, and is a small one composed of one or a plurality of small loops. The RF coil has a loop diameter that does not exceed the thickness of the neck of the subject, and a small RF coil is disposed in the vicinity of the neck of the subject by the disposing means, and the head RF coil is disposed by the control processing means. And using a small RF coil to receive the magnetic resonance signal from the subject and reconstruct the tomographic image information from the magnetic resonance signal, so that the image information over the entire head and the high sensitivity near the neck Detailed image information can be freely acquired by the operator, disease information acquired from image information over the entire head and disease information acquired from detailed image information in the vicinity of the cervix, at the same time, with relevance Efficient It can be.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the overall configuration of a magnetic resonance imaging apparatus.
FIG. 2 is a diagram showing a configuration of a head RF coil and a small RF coil of the embodiment.
FIG. 3 is a diagram showing an arrangement of a head RF coil and a small RF coil according to the embodiment on a cradle.
FIG. 4 is a diagram illustrating a configuration of a data collection unit according to the embodiment.
FIG. 5 is a flowchart showing the operation of the magnetic resonance imaging apparatus of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 Magnet system 102 Main magnetic field coil part 106 Gradient coil part 108 Transmission coil part 110 Head RF coil 116 Small RF coil 120 Cradle 121, 122 Arm 123 Headrest 130 Gradient drive part 140 Transmission drive part 150 Data collection part 160 Scan controller part 170 Data processing unit 180 Display unit 190 Operation unit 199 Control processing unit 210-240 Large loop coil 250-280 Small loop coil 320 Reception unit 321-328 Reception unit 330 Detection unit 340 A / D conversion unit

Claims (11)

A head RF coil consisting of a plurality of large loops having a loop diameter of approximately the same size as the head of the subject;
A small RF coil consisting of one or a plurality of small loops having a loop diameter not exceeding the thickness of the neck of the subject;
Disposing means for disposing the small RF coil in the vicinity of the neck of the subject;
Control processing means for receiving a magnetic resonance signal from the subject using the head RF coil and the small RF coil, and reconstructing tomographic image information from the magnetic resonance signal;
A magnetic resonance imaging apparatus comprising: 2. The magnetic resonance according to claim 1, wherein when the head RF coil and the small RF coil are formed of a rectangular large loop and a small loop, the diagonal length of the rectangle is a loop diameter. Imaging device. 3. The magnetism according to claim 1, wherein the head and the neck have a maximum length and a thickness of a cross section orthogonal to the midline of the subject. Resonance imaging device. 4. The magnetic resonance imaging according to claim 1, wherein in the head RF coil, a large loop surface surrounded by the large loop partially overlaps between the adjacent large loops. 5. apparatus. 5. The small RF coil according to claim 1, wherein when the small RF coil includes a plurality of adjacent small loops, the small loop surfaces surrounded by the small loops partially overlap each other. Magnetic resonance imaging apparatus. The said arrangement | positioning means is equipped with the fixing means which fixes the said small loop coil to the arbitrary space of the said neck part with mobility, The one of Claim 1 thru | or 5 characterized by the above-mentioned. Magnetic resonance imaging apparatus. The magnetic resonance imaging apparatus according to claim 6, wherein the arranging unit includes a pair of the fixing units at symmetrical positions sandwiching the neck. 8. The head RF coil according to claim 4, wherein a point where two large loops constituting the partially overlapping large loop surface overlap is a ground point common to the two large loops. The magnetic resonance imaging apparatus according to any one of the above. The head RF coil is composed of a plurality of large loops of the same shape that form a cylindrical shape by combining the large loop surfaces, and the large loops are arranged at equal intervals on a circumference forming a circular cross section of the cylindrical shape. The magnetic resonance imaging apparatus according to claim 4, wherein the magnetic resonance imaging apparatus is a cylindrical coil. The said cylindrical coil, when comprised from four or more even-numbered large loops, it groups for every two adjacent large loops, The said earthing | grounding point is provided for every said grouping, It is characterized by the above-mentioned. 9. The magnetic resonance imaging apparatus according to 9. When the cylindrical coil is placed on a base plate parallel to the long axis direction forming the cylindrical tube, the cylindrical coil includes two grounding points in one plane parallel to the base plate. The magnetic resonance imaging apparatus according to claim 10.

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