JP4991235B2 - Magnetic resonance imaging system - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus, and more particularly to a technique for stably operating a shim coil that dynamically corrects the static magnetic field uniformity in a measurement space.

  A magnetic resonance imaging system that uses the nuclear magnetic resonance (NMR) phenomenon to obtain tomographic images of the human body from the density distribution in the body of the main substance protons that make up the subject and the spatial distribution of the relaxation time of nuclear spins in the subject ( Hereinafter, it may be referred to as an MRI apparatus) is widely used in medical institutions.

  This MRI device has excellent contrast resolution, is considered non-invasive because it does not use ionizing radiation, the images obtained are less susceptible to bone and air, and is sensitive to fluid behavior, so it is vascular It has features such as being effective for diagnosis of diseases and spinal cord regions.

In recent years, ultra-high-speed imaging methods such as single-shot or multi-shot EPI (echo planar imaging) have been developed and put into practical use in order to meet the need for shortening the time required for imaging. Has been. In order to cope with such an ultra-high-speed imaging method, it is necessary to give positional information to each signal emitted from the measurement object using a pulse sequence accompanied by high-speed inversion of the gradient magnetic field pulse. For this reason, since a large pulse current flows through the gradient coil placed in the static magnetic field, a large Lorentz force acts on the gradient coil, causing mechanical distortion in the gradient coil.
Since this phenomenon repeatedly acts, if the gradient magnetic field coil vibrates and further the gradient magnetic field pulse is reversed at high speed, the vibration increases.

  When such a gradient magnetic field pulse is generated, mechanical distortion occurs in the gradient magnetic field coil, the coil unit of the high frequency coil, and the like by the Lorentz force, thereby vibrating the entire unit.

Due to this vibration, the image quality deteriorates due to the B radio waves and induction electrons generated by the friction between the metal parts of the coil unit.
Therefore, there is a technique disclosed in Patent Document 1 as a technique for solving the problem of the B radio wave and induction electrons.
This is because, in at least a part of the fastening parts of the plurality of component parts constituting the unit, the component parts are brought into metal contact with each other at a place requiring electrical connection, and the mounting screw and the component part The metal contact is avoided, and the metal contact is avoided between each of the plurality of component parts and the mounting screw at a place where an electrical connection is not required and a physical fixation is required.
Japanese Patent Laid-Open No. 2003-102703

  However, the cause of image quality degradation caused by the Lorentz force acting on the gradient magnetic field coil is the non-uniformity of the static magnetic field in addition to the B radio wave and induction electrons generated by the friction between the metal parts of the coil unit. Although the contact resistance of the fixed part that fixes the terminal of the shim coil to be corrected changes, and there is a concern about image quality deterioration due to the change in the static magnetic field correction current that flows through the shim coil, the above-mentioned Patent Document 1 describes the shim coil terminal fixing part. Even the problem of static magnetic field fluctuations caused by changes in contact resistance is not taken into consideration.

  That is, when vibration due to the Lorentz force of the gradient magnetic field coil is transmitted to the shim coil portion, the metal member that fixes the terminal of the shim coil vibrates, and the contact resistance value of the fixed portion changes to disturb the static magnetic field, thereby causing an image. Artifacts may occur, but this has not been seen as a problem until recently.

However, as described above, the gradient magnetic field is required to have higher speed and higher strength in order to cope with recent ultrahigh-speed imaging methods.
For this reason, the gradient magnetic field power source for supplying the gradient magnetic field current has been increased in current and voltage, and accordingly, the resistance change of the fixed portion of the shim coil terminal due to the vibration tends to become larger.

In addition, since the uniformity of the static magnetic field is improved and a high-function sequence is possible, a slight disturbance of the magnetic field is regarded as a problem.
For this reason, image artifacts due to the static magnetic field inhomogeneity caused by the change in the contact resistance of the fixed portion of the shim coil terminal are already negligible.

  Further, in order to stably obtain a high-quality image free from the image artifact so that the contact resistance of the fixed portion of the shim coil terminal does not change, the resistance value of the shim coil portion due to the change of the contact resistance is monitored, It is necessary to maintain the fixed portion so that the resistance value is always within a predetermined range.

  Therefore, the present invention has a structure in which the contact resistance of the fixed portion of the shim coil terminal for correcting the static magnetic field inhomogeneity is not affected by the Lorentz force acting on the gradient magnetic field coil, and the contact resistance value of the fixed portion of the shim coil terminal. And providing a magnetic resonance imaging apparatus that can stably acquire a high-quality image by reducing the image artifacts by maintaining the fixed portion so that the resistance value is always within a predetermined range. Objective.

  In order to achieve the above object, the magnetic resonance imaging apparatus of the present invention is configured as follows. That is, a plurality of static magnetic field generating means for applying a static magnetic field in a measurement space in which a subject is arranged, and a plurality of metal conductors wired to a pattern formed on a film-like substrate for correcting the non-uniformity of the static magnetic field Shim coils, a gradient magnetic field generating means for generating a gradient magnetic field in the static magnetic field region, a high frequency magnetic field generating means for generating a high frequency magnetic field for causing nuclear magnetic resonance in the subject, and a nucleus from the subject Receiving means for receiving a magnetic resonance signal, signal processing means for performing image reconstruction calculation using the nuclear magnetic resonance signal received by the receiving means, and pulse sequence control for controlling a pulse sequence for measuring the nuclear magnetic resonance signal A magnetic resonance imaging apparatus comprising: means for fixing a plurality of shim coil terminals having a mechanical strength higher than that of the film of the film base material. Providing the reinforcing means by members.

The reinforcing member of the reinforcing means is made of a glass fiber-containing resin material, and after the reinforcing member is bonded and cured, the fixing portion is bonded and fixed with an adhesive having a mechanical strength stronger than the film of the film-like substrate. .
Further, the adhesive material is used to bond the lead wires from which the telegraph signals are derived from the terminals of the plurality of shim coils.
A slit for increasing the mechanical strength of the contact surface between the reinforcing member and the film base is provided around the reinforcing member.

  Further, the magnetic resonance imaging apparatus of the present invention compares resistance detection means for detecting the resistance of the shim coil including the resistances of the plurality of shim coil terminal fixing portions with the resistance value detected by this means and a preset reference value. Comparison means, determination means for determining whether the resistance value of the fixed portion of the shim coil terminal is normal or abnormal based on the comparison result of the means, and notification means for notifying the determination result by the determination means Prepared.

  The resistance detecting means includes a current detecting means for detecting a current flowing through the shim coil, a voltage detecting means for detecting a voltage applied to the shim coil and a fixed portion of the shim coil terminal, and a voltage value detected by the voltage detecting means. And dividing means for dividing by the current value detected by the current detecting means.

  The resistance detection means detects only the resistance values of the plurality of shim coil terminal fixing portions, and the determination means determines whether the resistance value detected by the comparison means is within a predetermined range (reference value). The determination result may be notified by the notification means. In this case, the voltage detected by the voltage detecting means is the voltage of the shim coil terminal fixing portion.

  According to the present invention, the fixing portion for fixing the plurality of shim coil terminals is reinforced by the reinforcing member having a mechanical strength stronger than that of the film of the film base material, and is affected by the Lorentz force acting on the gradient magnetic field coil. Since there is no structure, the variation of the electric resistance value of the shim coil terminal fixing part can be reduced, and the uniformity of the static magnetic field can be kept substantially constant, thereby reducing image artifacts due to the static magnetic field strength fluctuation, A magnetic resonance imaging apparatus that can stably acquire a high-quality image can be provided.

  Further, since it is determined whether or not the resistance values of the plurality of shim coil terminal fixing portions are within a predetermined range in which the static magnetic field strength is substantially constant, the result is notified. Thus, the fixing portion of the shim coil terminal can be properly maintained, and thereby a magnetic resonance imaging apparatus that can stably acquire a high-quality image can be provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the invention, and the repetitive description thereof is omitted.

  The MRI apparatus uses a nuclear magnetic resonance (hereinafter referred to as “NMR”) phenomenon to obtain a tomographic image of an examination site of a subject, and FIG. 1 shows magnetic resonance imaging (hereinafter referred to as “MRI”) according to the present invention. ) In an overall perspective view of the apparatus, a gantry 1, an external unit 2 including a signal processing apparatus for processing various signals, and the relay cable 3 for electrically connecting the unit 2 and each component of the gantry 1 And is configured.

The gantry 1 includes a static magnetic field generating device 4 that generates a static magnetic field around the subject, and an RF coil 5 (for the head) that irradiates a high-frequency magnetic field for inducing an NMR phenomenon in a hydrogen nucleus constituting the subject. Example) and a gradient magnetic field coil (not shown in FIG. 1) for generating a gradient magnetic field for giving position information to an NMR signal emitted from the subject.
The RF coil 5 is an example for the head, and the present invention is not limited to this, but can be applied to other parts including the whole body.

FIG. 2 shows a cross-sectional view of the gantry of FIG. The static magnetic field generating magnets 6a and 6b (hereinafter collectively referred to as 6) as the static magnetic field generating device 4 are vertically opposed to each other with the measurement space A in which the subject is inserted therebetween (a is the lower side) , B represents the upper side, the same applies hereinafter), and a gradient magnetic field for applying a gradient magnetic field in the three-axis directions of X, Y, and Z to the subject so as to cover each space A side of these magnets. Coils 7a and 7b (hereinafter collectively referred to as 7) are attached.
Further, shim coils 8a and 8b (hereinafter collectively referred to as 7) for uniformly correcting the static magnetic field generated by the static magnetic field magnet 6 between the static magnetic field generating magnet 6 and the gradient magnetic field coil 7 are provided. Has been placed.

  The magnetic circuit thus formed forms a gradient magnetic field by forming a static magnetic field in the space A and supplying a pulsed current to the gradient magnetic field coil 7.

Further, on the space A side of the gradient magnetic field coil 7, irradiation RF coils 9a and 9b (hereinafter collectively referred to as 9) for irradiating a subject with a high-frequency magnetic field are arranged, and further, a receiving coil (not shown) is illustrated. (RF coil 5 in FIG. 1).
Further, the outer peripheral portion of the magnetic field generating device constituted by the static magnetic field generating magnet 6 and each coil is covered with a cover 10, and this cover 10 is necessary for safety such as aesthetics and insulation.

  Although not shown, the external unit 2 has a display device for displaying a reconstructed image or the like processed by the signal processing device in addition to the signal processing device, and a subject placed on the subject. A bed movable in the body axis direction of the examiner, a bed control unit for controlling the movement of the bed, an operation console for performing a photographing operation by setting a photographing sequence, parameters necessary for photographing, a photographing section, and the like; And a control device for controlling the entire system including a pulse sequence control for controlling a pulse sequence for measuring the nuclear magnetic resonance signal based on an operation signal set by an operation console.

  The MRI apparatus configured as described above receives an NMR signal emitted from the subject by nuclear magnetic resonance by the receiving coil, and performs image reconstruction calculation using the received NMR signal by the signal processing apparatus of the external unit 2. The MRI image is displayed on the display device for diagnosis.

  The direction of the static magnetic field of the static magnetic field generator 4 may be vertical or horizontal, and the static magnetic field generation method may be a permanent magnet method, a normal conduction method, or a superconductivity method. That is, the present invention is not limited to the static magnetic field direction and the static magnetic field generation method, and the magnetic field generation device may be configured to correspond to the static magnetic field direction and the static magnetic field generation method.

  Next, the shim coil 8, which is a main part of the present invention, will be described. As described above, the shim coil 8 is a coil for uniformly correcting the static magnetic field, and this coil includes a plurality of coil groups. As an example of the arrangement relationship between the coil group, the RF coil 9, and the gradient magnetic field coil 7, This will be described in more detail with reference to FIG. 3 in which the cross section of the lower part of FIG. 2 is enlarged.

In FIG. 3, a shim coil 8a (upper is 8b) is composed of a plurality of coils 81a to 85b (upper is 81b to 85b) (an assembly of coils that output a magnetic field having only a specific spatial component), and a ZX channel coil 81a (upper 81b) and, with the ZY channel coil 82a (upper 82b), and the XY channel coil 83a (upper 83 b), and X ² -Y ² channels of coils 84a (upper 84b), Z ^n-channel Coil 85a (the upper side is 85b).

FIG. 4 is a circuit configuration for supplying a current for correcting the non-uniformity of the static magnetic field to the shim coil 8 (hereinafter referred to as a shim correction circuit), a shim power source 40 for static magnetic field correction, and a shim correction connected to this power source. The shim correction current supply circuit includes a current supply circuit 50 and a shim coil unit 51 (51a is a lower shim coil unit and 51b is an upper shim coil unit) of a shim coil group to which correction current is supplied from the shim correction current supply circuit. 50 and the shim coil unit 51 are a ZX shim correction current supply circuit 41 for supplying a static magnetic field correction current to the ZX channel shim coils 81a and 81b, and a ZY shim for supplying a static magnetic field correction current to the ZY channel shim coils 82a and 82b. a correction current supply circuit 42, a shim coil 83a of the XY channel, the XY shim correction current supply circuit 43 for supplying a static magnetic field correction current to 83 b, X ² -Y ² channels shim coils 84a, a static magnetic field to 84b An XY shim correction current supply circuit 44 for supplying a Tadashiyo current, constituted by a shim coil 85a of Z ^n-channel, and supplies a static magnetic field correction current to 85b Z ⁿ shim correction current supply circuit 45.

  The shim correction circuit configured in this way adjusts the correction current supplied to each shim coil to a desired value, and flows the correction current to obtain a spatial uniformity of the required ppm or less with respect to the static magnetic field. To do.

  The plurality of shim coil groups form a predetermined pattern on the film-like base material, and in a configuration in which a metal conductor is wired on this pattern, a terminal is provided on the film-like base material to connect the relay cable 3, This connection point is fixed by a fixing member.

In the shim coil group having such a configuration, the Lorentz force generated in the gradient magnetic field coil causes mechanical distortion in the gradient magnetic field coil, the coil unit of the high-frequency coil, and the like, which causes the entire unit to vibrate. When transmitted to the shim coil unit including the group, the contact resistance value of the fixing portion changes due to the vibration of the metal member that fixes the shim coil group.
When this contact resistance value changes, the correction current flowing through the shim coil changes and disturbs the static magnetic field, thereby generating image artifacts.

Hereinafter, the structure of the shim coil mounting part that is not affected by the Lorentz force of the gradient magnetic field coil and the contact resistance value of the shim coil terminal fixing part, which are the objects of the present invention, are monitored, and the resistance value is always within a predetermined range. A means for supporting the maintenance of the fixed part will be described.
<< First Embodiment >>

  FIG. 5 shows the structure of a shim coil mounting portion according to the present invention. FIG. 5 (a) shows a plurality of shim coils and a fixing portion for electrically connecting input / output terminals of these shim coils and an external unit to fix the connecting portion. The top view which shows the structure of (2), (b) is the sectional drawing.

In FIG. 5 (a), as described above, the shim coil group forms a predetermined pattern on the film-like substrate 8c, and a thin metal conductor 8d is wired on the pattern, and the metal conductor 8d and the external unit 2 are wired. And a lead wire 8e for relaying (see FIG. 1).
Then, a crimp terminal 8f is connected to the lead wire 8e, the crimp terminal 8f and the thin metal conductor 8d are coupled by a rivet 8g, and the coupling portion is fixed to the film-like substrate 8c.

  When a pulsed current is applied to the gradient coil 7 arranged in the static magnetic field in the shim coil unit having such a structure, the gradient coil 7 vibrates, and when this vibration is transmitted to the shim coil unit, the film-like substrate The material 8c and the thin metal conductor 8d are deformed.

  Fig. 6 is a schematic diagram showing the state before and after deformation. (A) is before deformation, (b) is after deformation, and the contact area between the crimp terminal 8f and the thin metal conductor 8d is changed by this deformation. Changes. For this reason, the apparent resistance value of the shim coil changes, the correction current flowing through the shim coil changes, the static magnetic field is disturbed, and a predetermined static magnetic field uniformity cannot be obtained.

Therefore, as shown in FIG. 5, a reinforcing plate 8h (reinforcing means) as a reinforcing member is disposed between the rivet 8g and the film-like substrate 8c, the thin metal conductor 8d, and the crimp terminal 8f, and this reinforcing plate 8h Is adhered to the film-like substrate 8c with an adhesive to prevent deformation due to the vibration.
The reinforcing member is a reinforcing plate made of a resin containing glass fiber, thereby making the mechanical strength much greater than when the crimp terminal 8f and the thin metal conductor 8d are coupled with a rivet 8g. Can do.

  Thus, by providing the reinforcing plate 8h, even if the shim coil unit vibrates, the periphery of the rivet is surrounded by the reinforcing plate 8h. Therefore, a local area is formed at the boundary between the outer peripheral portion of the reinforcing member and the film-like substrate 8c. Only by deformation, the inside of the reinforcing member moves as a uniform plane. For this reason, since the contact surface between the crimp terminal 8f and the thin metal conductor 8d does not fluctuate, the contact resistance of the contact surface becomes substantially constant, and stable magnetic field correction can be performed.

  Further, in order to increase the mechanical strength of the contact surface, the adhesive member that bonds the reinforcing member (reinforcing plate 8h) to the film substrate 8c is mechanically bonded to the thin metal conductor 8d. For example, an epoxy adhesive is used that is much stronger than the strength.

  By applying such a strong mechanical strength adhesive to cover the crimp terminal 8f completely, the contact surface between the thin metal conductor 8d and the crimp terminal 8f does not fluctuate even if the shim coil vibrates. Magnetic field correction can be performed.

Further, in order to increase the mechanical strength of the contact surface, a slit 8i is provided around the reinforcing member 8h, thereby increasing the mechanical strength difference between the reinforcing member 8h and the film base 8c in the vicinity thereof.
Thereby, since deformation due to vibration does not occur in the terminal portion, the rivet portion in the reinforcing member can be kept in a stable contact state.

  According to the first embodiment, the Lorentz that acts on the gradient magnetic field coil by reinforcing the fixing portion for fixing the plurality of shim coil terminals with the reinforcing member having higher mechanical strength than the film of the film-like substrate. Since the structure is not affected by force, the variation of the electric resistance value of the shim coil terminal fixing portion can be reduced, and the uniformity of the static magnetic field can be kept almost constant, thereby the image due to the fluctuation of the static magnetic field strength. Artifacts are reduced, and stable images with high image quality can be acquired.

<< Second Embodiment >>
Next, means for monitoring the contact resistance value of the shim coil terminal fixing portion and assisting the maintenance of the fixing portion so that the resistance value is always within a predetermined range will be described.

  This detects the total resistance value of the shim coil including the shim coil and the resistance of the shim coil terminal fixing part, the current flowing through each shim coil and the voltage applied to the shim coil part including the fixing part of the shim coil terminal, and detecting these The resistance value of the fixed portion of the shim coil terminal is calculated from the value, and the resistance value is compared with a reference value within a predetermined range to determine whether the fixed portion of the shim coil terminal is normal or abnormal. An example of a specific configuration is shown in FIG.

  Hereinafter, this will be described in detail with reference to FIG. In this figure, since the detection of the current flowing through the shim coil and the voltage applied to the shim coil unit is the same for all shim coil units, the ZX shim correction shim coil unit will be described here.

  In FIG. 7, the resistance value of the fixed portion of the shim coil terminal is monitored by detecting the current flowing through the shim coil and the voltage applied to the shim coil unit, the voltage detection unit 60, and the current value detected by the detection unit. A resistance value calculation unit 71 (first resistance detection means) that calculates the resistance value of the shim coil unit from the voltage value, a resistance value calculated by the calculation unit, and a reference value 72 (first reference value) within a predetermined range, A comparison unit 73 (first comparison unit), and a determination unit 74 (first determination unit) that determines whether the resistance value of the fixed portion of the shim coil terminal is normal or abnormal based on the result of comparison by the comparison unit. The resistance value calculation unit 71, the reference value 72, the comparison unit 73, and the determination unit 74 constitute a shim coil terminal fixing unit resistance value determination device 70.

  The current and voltage detector 60 of the shim coil detects the current flowing through the shim coil with a current detector 61 (current detecting means), and converts the voltage value converted by the voltage converter 62 into the resistance calculator 81g to input the shim coil The voltage detector 63 detects the voltage of 81a and its fixed part, the voltage of the shim coil 81b and its fixed part is detected by the voltage detector 64, and inputs these to the resistance calculation part 81g (the voltage detector 63 and The voltage detector 64 constitutes a first voltage detection means). The detected current value of the shim coil and the voltage value applied to the shim coil unit are input to the resistance calculating unit 81g, and the voltage value of the shim coil 81a and its fixed part is divided by the current value of the shim coil to generate the shim coil 81a. Similarly, the resistance value on the shim coil 81b side is obtained by dividing the voltage value of the shim coil 81b and its fixed part by the current value of the shim coil (the divider on the shim coil 81a side and the shim coil 81b side). The first divider is composed of the divider).

  The comparison unit 81h compares the calculated resistance values of the shim coil portions on the shim coil 81a side and the shim coil 81b side with the reference value 72 of the required range, which is an allowable range of the resistance values, and determines the result. Enter in 74.

Similarly to the above, for the other shim coils, the current and voltage of each shim coil are detected, and the resistance value of the shim coil part is calculated from the detected current and voltage (resistance value calculating parts 82g, 83g, 84g, 85g Then, the calculated resistance value is compared with a reference value 72 of a required range that is an allowable range of the resistance value (comparing units 82h, 83h, 84h, 85h), and the result is input to the determination unit 74.
The determination unit 74 identifies a shim coil having a resistance value other than the reference value of the required range that is an allowable range from the comparison results of all the shim coil units, displays the identified shim coil on the display device, and notifies The operator or the like is notified by the notification means (first notification means).

  In the shim coil terminal fixing portion resistance value determination device 70, each part may be configured by hardware, or the detected shim coil current and shim coil voltage value are converted into digital values using a micro computer (included in the resistance calculation unit). ), Division for calculating the resistance value by the digital signal, comparison with the reference value in the comparison unit, and determination of the comparison result may be performed by software.

In FIG. 7, the sum of the resistance of the shim coil and the contact resistance of the fixed part that fixes the shim coil terminal is used as the resistance value, but the present invention is not limited to this, and the contact resistance of the fixed part and A configuration in which the reference value (second reference value) of the contact resistance is compared may be used.
In this case, since the resistance value of the shim coil is known in advance, the resistance value of the shim coil and the resistance value of the shim coil calculated from the measured values of the voltage of the shim coil and the shim coil fixing unit are known. The known shim coil resistance value may be subtracted from the sum of the contact resistance value of the fixed part or the voltage of the shim coil fixed part is directly detected and calculated from the detected value and the current value flowing through the shim coil. (Second comparison means, second determination means, second notification means, second voltage detection means, second division means) may be used.

  According to the second embodiment described above, it is determined whether or not the resistance values of the plurality of shim coil terminal fixing portions are within a predetermined range in which the static magnetic field strength is substantially constant, and the result is notified. Therefore, it is possible to appropriately maintain the fixed portion of the shim coil terminal based on the notified information, thereby obtaining a stable image with high image quality.

1 is an overall perspective view of a magnetic resonance imaging apparatus according to the present invention. A sectional view of a gantry. The figure which shows the arrangement | positioning relationship between the shim coil which is the principal part of this invention which expanded the cross section of the lower part of a gantry cross section, and another element. The circuit block diagram which supplies the electric current which corrects the nonuniformity of a static magnetic field to a shim coil. FIG. 3 is a structural diagram of a shim coil mounting portion showing the first embodiment of the present invention. The schematic diagram which shows the mode before and behind a deformation | transformation of a shim coil mounting part with the Lorentz force of a gradient magnetic field coil. The block diagram of the apparatus which monitors the resistance value of a shim coil terminal fixing | fixed part.

Explanation of symbols

  1 Gantry, 2 External unit, 3 Relay cable, 4 Static magnetic field generator, 5 Receiving RF coil, 6 Static magnetic field generator magnet, 7 Gradient magnetic field coil, 8, 81a, 82a, 83a, 84a, 85a Shim coil, 8c Film base Material, 8d thin metal conductor, 8e lead wire, 8f crimp terminal, 8g rivet, 8h reinforcing plate, 8i slit, 9 irradiation RF coil, 10 cover, 40 shim power source for static magnetic field correction, 50 shim correction current supply circuit, 51 shim coil Unit, 60 Current / Voltage detector, 61 Current detector, 62, 63 Voltage detector, 70 Shim coil terminal fixing part Resistance value determination part, 71 Resistance calculation part, 72 Reference value, 73 Comparison part, 74 Determination part

Claims (9)

A static magnetic field generating means for applying a static magnetic field in a measurement space in which the subject is arranged;
A plurality of shim coils formed by wiring metal conductors in a pattern formed on a film-like substrate for correcting the non-uniformity of the static magnetic field;
A gradient magnetic field generating means for generating a gradient magnetic field in the static magnetic field region;
High-frequency magnetic field generating means for generating a high-frequency magnetic field for causing nuclear magnetic resonance in the subject;
Receiving means for receiving a nuclear magnetic resonance signal from the subject; signal processing means for performing image reconstruction calculation using the nuclear magnetic resonance signal received by the receiving means;
A magnetic resonance imaging apparatus comprising a pulse sequence control means for controlling a pulse sequence for measuring the nuclear magnetic resonance signal,
A magnetic resonance imaging apparatus comprising: a reinforcing member that has a mechanical strength stronger than that of the film of the film base material at a fixing portion that fixes the terminals of the plurality of shim coils.   2. The magnetic resonance imaging apparatus according to claim 1, wherein the reinforcing member of the reinforcing means is made of a glass fiber-containing resin material.   3. The magnetic resonance imaging apparatus according to claim 1, wherein the fixing member is bonded and fixed with an adhesive having a mechanical strength higher than that of the film of the film-like substrate after the reinforcing member is bonded and cured. .   The magnetic resonance imaging apparatus according to claim 3, wherein the adhesive material is used to bond lead wires from which the telegraph signals are derived from terminals of the plurality of shim coils.   The magnetic according to any one of claims 1, 2, 3 and 4, wherein a slit for increasing the mechanical strength of the contact surface between the reinforcing member and the film base is provided around the reinforcing member. Resonance imaging device.   A first resistance detecting means for detecting the resistance of the shim coil including the resistances of the plurality of shim coil terminal fixing portions, and a first comparison for comparing the resistance value detected by this means with a preset first reference value And a first determination means for determining whether the resistance value of the fixed portion of the shim coil terminal is normal or abnormal based on the comparison result of the means, and a first notification for notifying a result determined by the determination means The magnetic resonance imaging apparatus according to claim 1, further comprising: means.   A second resistance detecting means for detecting the resistance of the plurality of shim coil terminal fixing portions; a second comparing means for comparing a resistance value detected by the means with a preset second reference value; and And a second determination means for determining whether the resistance value of the fixed portion of the shim coil terminal is normal or abnormal, and a second notification means for notifying a result determined by the determination means. The magnetic resonance imaging apparatus according to claim 1, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus.   The first resistance detection means includes a current detection means for detecting a current flowing through the shim coil, a first voltage detection means for detecting a voltage applied to the fixed portion of the shim coil and the shim coil terminal, and the voltage detection. 7. The magnetic resonance imaging apparatus according to claim 6, further comprising a first dividing unit that divides the voltage value detected by the unit by the current value detected by the current detecting unit.   The second resistance detection means includes a current detection means for detecting a current flowing through the shim coil, a second voltage detection means for detecting a voltage applied to a fixed portion of the shim coil terminal, and a detection by the voltage detection means. The magnetic resonance imaging apparatus according to claim 7, further comprising: a second dividing unit that divides the measured voltage value by the current value detected by the current detecting unit.

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