JP6151330B2 - Gradient magnetic field power supply and magnetic resonance imaging apparatus - Google Patents

Description

  The present invention relates to a gradient magnetic field power transformer used in a magnetic resonance imaging apparatus.

  Magnetic resonance imaging equipment uses a phenomenon in which the energy of a high-frequency magnetic field rotating at a specific frequency is resonantly absorbed when a group of nuclei having a specific magnetic moment is placed in a uniform static magnetic field. It is a device that visualizes chemical and physical microscopic information of a substance or observes a chemical shift spectrum. Such a magnetic resonance imaging apparatus is extremely effective as a method for non-invasively obtaining an anatomical sectional view of a human body. In particular, it is widely used as a diagnostic device for the central nervous system such as the brain covered with bone.

  In such a magnetic resonance imaging apparatus, as a mechanism for forming a magnetic field (gradient magnetic field) in which the intensity of the magnetic field changes linearly in each direction of the orthogonal axes of space (that is, the x, y, and z axes), A gradient magnetic field coil, a gradient magnetic field power supply device for supplying a current to the gradient magnetic field coil, and the like are provided.

  FIG. 10 is a diagram illustrating a configuration of a general gradient magnetic field power supply device. As shown in the figure, the gradient magnetic field power supply apparatus 50 includes an X channel (Xch) gradient magnetic field power supply 51, a Y channel (Ych) gradient magnetic field power supply 52, and a Z channel (Zch) gradient magnetic field power supply 53. Yes. For example, three-phase AC400V power is used as a driving power source for the gradient magnetic field power supply device. The three-phase 400 V power supplied to the gradient magnetic field power supply 50 is distributed by a power transformer (transformer) in the gradient magnetic field power supply 50 and supplied to each gradient magnetic field power supply 51, 52, 53. Each gradient magnetic field power supply 51, 52, 53 operates independently according to the control from the control device, and supplies current to the gradient magnetic field coil for generating the gradient magnetic field in the corresponding coordinate axis direction.

JP 2000-199782 A JP 2008-307309 A Japanese Patent Laid-Open No. 10-5189

  However, the conventional gradient magnetic field power supply has the following problems, for example. That is, the power transformer of the gradient magnetic field power supply device of the conventional magnetic resonance imaging apparatus has a single phase for each primary winding of three phases (U phase, V phase, W phase) as shown in FIG. Winding the secondary winding. In this single-phase secondary winding, for example, as shown in FIG. 11, the secondary windings corresponding to each channel are not spatially evenly arranged between the U-phase, V-phase, and W-phase. (For example, looking at the X channel (Xch) in FIG. 11, the number of secondary windings of the X channel (Xch) wound around the primary winding of the W phase is the number of primary windings of the U phase and V phase. Less than the number of secondary windings of the X channel (Xch) wound around the Therefore, the load on each phase of the primary winding corresponding to each output channel of the X channel (Xch), the Y channel (Ych), and the Z channel (Zch) can be biased. For this reason, there is a problem that the load of each phase of the primary winding corresponding to a specific output channel can be biased, and voltage fluctuation at the time of output becomes large.

Furthermore, in recent years, the output current value tends to increase, and it can be said that voltage fluctuations in the gradient magnetic field power supply device tend to occur frequently. For this reason, the magnetic resonance imaging apparatus has a function of interlocking according to the value of the output voltage and protecting the subsequent circuit. However, if the width of the voltage fluctuation is large, an imaging method in which the voltage value exceeds the interlock threshold cannot be performed. In particular, when an imaging method such as Echo Planar Imaging (EPI) is executed, current flows intensively in the read channel, so that each primary winding corresponding to a specific output channel It is easy to bias the phase load. Also,
Each phase of the primary winding of the power transformer leveles the power secured to each output channel, and even if the output current is uneven between the output channels, the power is more stable than before Are provided, and a magnetic resonance imaging apparatus including the gradient magnetic field power supply device is provided.

  In order to achieve the above object, the present invention takes the following measures.

The magnetic resonance imaging apparatus according to the embodiment supplies a magnetic field from the gradient magnetic field power supply device to each gradient magnetic field coil corresponding to each axial direction of the spatial coordinate axis, thereby generating a magnetic field along each direction in the spatial coordinate axis direction in the static magnetic field space. In the magnetic resonance imaging apparatus for forming a gradient magnetic field that changes, the gradient magnetic field power supply device is a transformer that supplies power supplied to the primary winding to the current output circuit by a plurality of secondary windings, The number of phases of the secondary winding is a natural number multiple of the number of phases of the primary winding, and each phase of the primary winding is wound with the same number of secondary windings, and the secondary winding As each phase of the winding, an output channel corresponding to each axial direction of the spatial coordinate axis is wound, and the same among the plurality of secondary windings for the output channel in each phase of the primary winding The output channel in the axial direction A plurality of secondary windings corresponding to each phase are separated by sandwiching secondary windings related to the other axial direction in at least one of a core winding direction and a concentric circle direction of the primary winding corresponding to each phase. Having a transformer in place .
Gradient magnetic field power supply device implementation form, by supplying a current to each gradient coil corresponding to each axial space coordinate axis gradient magnetic field along each direction of the space coordinate axis direction in the static magnetic field space is changed a gradient magnetic field power supply apparatus for use in a magnetic resonance imaging apparatus for forming a magnetic field, a transformer for supplying the current output circuit power supplied to the primary winding of a plurality of secondary windings, said secondary is a natural number multiple of the number of phases of the winding number of phases of the primary winding, each phase of the primary winding, the be wound output channels corresponding to each axial space coordinate axis, wherein the output channels of the plurality of secondary windings in each phase of the primary windings, the one even without least Chi sac core direction and the concentric direction of the primary winding corresponding to the phases, other of said shaft clamping the secondary winding with respect to the direction In having a transformer isolation to being disposed.

FIG. 1 is a block diagram of a magnetic resonance imaging apparatus 1 according to this embodiment. FIG. 2 is a block diagram for explaining the configuration of the gradient magnetic field power supply device 17. FIG. 3 is a diagram illustrating an example of the configuration of the transformer 171 included in the gradient magnetic field power supply device 17. FIG. 4 is a diagram for explaining the first embodiment. FIG. 5 illustrates the magnetic coupling between the secondary windings when the secondary winding U phase corresponding to each of the X channel, the Y channel, and the Z channel is wound around the primary winding U phase one by one. It is a figure for doing. 6A, 6B, and 6C, five secondary winding U phases corresponding to the X channel, Y channel, and Z channel are wound around the primary winding U phase, respectively. It is a figure for demonstrating the magnetic coupling of the secondary winding in a case. FIG. 7 is a diagram illustrating an example of a scan sequence of echo planar imaging (EPI). FIG. 8 shows an example of a transformer in which secondary windings corresponding to each channel are distributedly arranged when five secondary windings are wound around each primary winding corresponding to each phase. FIGS. 9A, 9B and 9C are diagrams showing the state of magnetic coupling in the distributed arrangement of secondary windings shown in FIG. FIG. 10 is a diagram illustrating a configuration of a general gradient magnetic field power supply device. FIG. 11 is a diagram showing a configuration of a transformer of a conventional gradient magnetic field power supply device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.

  FIG. 1 is a block diagram of a magnetic resonance imaging apparatus 1 according to this embodiment. As shown in the figure, the magnetic resonance imaging apparatus 1 includes a static magnetic field magnet 11, a cooling system control unit 12, a gradient magnetic field coil 13, a high frequency transmission coil 14, a high frequency reception coil 15, a transmission unit 18, a reception unit 19, and data. A processing unit 20 and a display unit 24 are provided.

  The static magnetic field magnet 11 is a magnet that generates a static magnetic field, and generates a uniform static magnetic field.

  The cooling system control unit 12 controls the cooling mechanism of the static magnetic field magnet 11.

  The gradient magnetic field coil 13 is provided inside the static magnetic field magnet 11 and has a shorter axis than the static magnetic field magnet 11 and is provided for each axial direction of the X, Y, and Z axes. Each gradient coil 13 forms an independent output channel, and converts the pulse current supplied from the gradient magnetic field power supply device 17 into a gradient magnetic field. The signal generation site (position) is specified by the gradient magnetic field generated by the gradient magnetic field coil 13.

  In this embodiment, the Z-axis direction is the same as the direction of the static magnetic field. In the present embodiment, the gradient magnetic field coil 13 and the static magnetic field magnet 11 are assumed to be cylindrical. The gradient coil 13 is disposed in a vacuum by a predetermined support mechanism. This is because the vibration of the gradient magnetic field coil 13 generated by applying the pulse current is not propagated to the outside as a sound wave from the viewpoint of noise reduction.

  The high frequency transmission coil (RF transmission coil) 14 is a coil for applying a high frequency pulse for generating a magnetic resonance signal to the imaging region of the subject. The high-frequency transmission coil 14 is an RF coil for whole body, and can be used as a reception coil when, for example, an abdomen is imaged.

  The high-frequency receiving coil (RF receiving coil) 15 is a coil for receiving magnetic resonance from the subject, which is installed so as to sandwich the subject in the vicinity of the subject, preferably in a close contact state. The high-frequency receiving coil 15 generally has a dedicated shape for each part.

  1 illustrates a cross coil system in which a high-frequency transmission coil and a high-frequency reception coil are separated from each other, but a configuration using a single coil system in which these coils are shared by one coil may be employed.

  The gradient magnetic field power supply device 17 generates a pulse current for forming a gradient magnetic field and supplies it individually to each gradient magnetic field coil 13. The detailed configuration of the gradient magnetic field power supply device 17 will be described later.

  The transmission unit 18 includes an oscillation unit, a phase selection unit, a frequency conversion unit, an amplitude modulation unit, and a high frequency power amplification unit (each not shown), and transmits a high frequency pulse corresponding to the Larmor frequency to the transmission high frequency coil. To do. Due to the high frequency generated from the high frequency transmission coil 14 by the transmission, the magnetization of the predetermined atomic nucleus of the subject is excited.

  The receiver 19 has an amplifier, an intermediate frequency converter, a phase detector, a filter, and an A / D converter (each not shown). The receiving unit 19 amplifies the magnetic resonance signal (high frequency signal) received from the high frequency coil 14 and releases when the nuclear magnetization relaxes from the excited state to the ground state, and intermediate frequency conversion processing using the transmission frequency. , Phase detection processing, filter processing, and A / D conversion processing are performed.

  The display unit 24 displays a magnetic resonance image, a predetermined scanning screen, and the like.

  The data processing unit 20 is a computer system that processes data after reception to generate a magnetic resonance image, and includes a storage unit 201, a control unit 202, a data collection unit 203, a reconstruction unit 204, a signal correction unit 205, and an input unit. 207.

  The storage unit 201 stores collected magnetic resonance images, programs for executing various scan sequences (for example, scan sequences for executing echo planar imaging (EPI)), and the like.

  The control unit 202 includes a CPU, a memory, and the like (not shown), and controls the magnetic resonance imaging apparatus statically or dynamically as a control center of the entire system. In particular, the control unit 20 controls the gradient magnetic field power supply device 17 and the like when executing a scan sequence such as echo planar imaging (EPI).

  The data collection unit 203 collects the digital signal sampled by the reception unit 19.

  The reconstruction unit 204 performs post-processing, that is, reconstruction such as Fourier transform, on the data collected by the data collection unit 203 to obtain spectrum data or image data of a desired nuclear spin in the subject.

  The input unit 207 has an input device (mouse, trackball, mode switch, keyboard, etc.) for capturing various instructions, instructions, and information from the operator.

  The display unit 24 is an output unit that displays spectrum data or image data input from the data processing unit 20.

(Gradient magnetic field power supply)
Next, the gradient magnetic field power supply device 17 included in the magnetic resonance imaging apparatus 1 will be described in detail.

  FIG. 2 is a block diagram for explaining the configuration of the gradient magnetic field power supply device 17. As shown in the figure, the gradient magnetic field power supply device 17 includes a transformer 171, a rectifier 173, an Xch output circuit (Xch power switch) 175x, a Ych output circuit (Ych power switch) 175y, a Zch output circuit (Zch power switch) 175z. And a control circuit 177.

  The transformer 171 has a secondary winding having the same number of phases as the number of phases of the primary winding, or a constant (an integer of 2 or more) times the number of phases of the primary winding. In the present embodiment, for the sake of specific description, the case where the number of phases of the primary winding and the number of phases of the secondary winding are the same is taken as an example. The secondary winding corresponding to each phase is wound around the primary winding of each phase, and is distributed and arranged for each output channel. In the present embodiment, in order to make the description more specific, it is assumed that the number of phases is three phases of U phase, V phase, and W phase. Therefore, for example, as shown in FIG. 3, the transformer 171 includes a secondary winding U phase corresponding to the Xch output for the primary winding U phase, a secondary winding U phase corresponding to the Ych output, and a Zch output. The secondary winding U phase corresponding to is wound respectively. Similarly, the secondary winding V phase corresponding to the Xch output with respect to the primary winding V phase, the secondary winding V phase corresponding to the Ych output, and the secondary winding V phase corresponding to the Zch output respectively. Furthermore, the secondary winding W phase corresponding to the Xch output, the secondary winding W phase corresponding to the Ych output, and the secondary winding W phase corresponding to the Zch output are respectively wound around the primary winding W phase. It is wound.

  Note that the technical idea of the present invention can be applied to any number of phases as long as the number of phases is the same between the primary winding and the secondary winding without being limited to the example in which the number of phases is three. Is possible.

  The rectifier 173 generates a DC voltage and a DC current from the AC power output from the transformer 171.

  The Xch output circuit 175x, the Ych output circuit 175y, and the Zch output circuit 175z each output DC power from the rectifier 173 as a pulse current to the gradient magnetic field coil of the corresponding channel at a predetermined timing in accordance with a control signal from the control circuit 177. .

  The control circuit 177 performs control related to current output from the Xch output circuit 175x, the Ych output circuit 175y, and the Zch output circuit 175z to the gradient magnetic field coil of the corresponding channel in accordance with the control from the control unit 202.

  As described above, the transformer 171 of the gradient magnetic field power supply device 17 has the same number of phases of the secondary winding as that of the primary winding (in this case, three phases), and the secondary winding for each phase of the primary winding. Each phase of the winding is wound. Therefore, even if the output current is uneven between the output channels, it is possible to prevent the load from being unevenly distributed to each phase of the primary winding.

  In addition, the form of arrangement | positioning of the secondary winding which makes the number of phases the same as a primary winding is not restricted to the example of the said FIG. 3, but can consider various other things. Hereinafter, variations of the arrangement of the secondary winding will be described according to the following examples.

Example 1
The arrangement form of the secondary winding according to the first embodiment includes a plurality of secondary windings wound around each primary winding corresponding to each phase.

  FIG. 4 is a diagram for explaining the present embodiment. For example, corresponding to the primary winding U phase, the secondary winding U phase corresponding to the Xch output and the secondary winding U phase corresponding to the Ych output. FIG. 6 is a diagram showing an example in which five secondary winding U phases corresponding to Zch outputs are arranged along each concentric direction (winding direction) by five (5 circuits each). The structure of the secondary winding with respect to the primary winding V phase and the primary winding W phase is the same.

  According to such a configuration, the number of secondary windings corresponding to each phase of the U phase, V phase, and W phase is the same as that of each primary winding corresponding to each phase of the U phase, V phase, and W phase. Each is wound (five in the example of FIG. 4). In this way, by making the number of secondary windings corresponding to each output of Xch, Ych, and Zch equal to each primary winding corresponding to each phase of U phase, V phase, and W phase, The electric power secured by the primary winding of each phase with respect to the secondary winding corresponding to each output can be leveled. As a result, even when the output current is uneven between the output channels, the load of the primary winding is not uneven, and a stable secondary voltage can be supplied.

(Example 2)
In general, in addition to the electromagnetic interaction between the primary winding and the secondary winding, an electromagnetic interaction occurs between the secondary windings. When such electromagnetic interaction is not perfect, if there is a channel with a heavy load and a large current flow, and a channel with a light load and a large current flow, the voltage of the secondary winding of the light load channel will have a tolerance. May rise beyond. In order to solve this problem, the arrangement form of the secondary winding according to the second embodiment is applied to each output channel when the secondary winding corresponding to each phase is wound around each primary winding corresponding to each phase. The magnetic coupling between the secondary windings is leveled.

  FIG. 5 shows, for example, the secondary winding U phase corresponding to the Xch output for the primary winding U phase, the secondary winding U phase corresponding to the Ych output, and the secondary winding U phase corresponding to the Zch output. It is a figure for demonstrating the magnetic coupling of the secondary winding at the time of winding one by one.

  As shown in the figure, the secondary winding Sy (corresponding to Ych) is at the center of the primary winding U phase, and the secondary winding Sx (corresponding to Xch) is at one end of the primary winding U phase. The next winding Sz (corresponding to Zch) is arranged on the other end side of the primary winding U phase.

  When the X channel (Xch) is selected as the output channel in the arrangement form of the secondary windings in the figure, current is supplied only to the secondary winding Sx, and the other two secondary windings Sy and Sz. Only a small amount of current is supplied. Therefore, the magnetic flux B1 formed by the primary winding U phase is mainly coupled with the magnetic flux B2x by the secondary winding Sx that is unevenly distributed with respect to the primary winding U phase. Further, it is considered that there is a leakage magnetic flux between the secondary winding Sx and the secondary winding Sz.

  When current flows only in the secondary winding Sx in this way, the output voltage of the secondary winding Sz corresponding to the Z channel, for example, may increase unintentionally due to the influence of the leakage magnetic flux. . This is because the magnetic flux increases in the secondary winding Sz in order to cancel the increase in the magnetic flux due to the primary winding that has been increased to cancel the magnetic flux due to the current in the secondary winding Sx (that is, ideally However, the increase in the magnetic flux in the iron core due to the increase in the current of the secondary winding Sx is canceled by the increase in the magnetic flux on the primary winding side. Due to the leakage magnetic flux between the secondary windings Sx and Sz, the increased magnetic flux on the primary winding side and the magnetic flux of the secondary winding Sx are not completely cancelled. This is because the voltage of the secondary winding Sz increases. Such a phenomenon occurs with respect to the secondary winding Sx even when the current flows only in the secondary winding Sz (when the current flows only in the secondary winding Sy, the secondary winding The distance to Sx and Sz is sufficiently close and even, and the influence is small).

  6 (a), 6 (b) and 6 (c) show the arrangement of the secondary winding shown in FIG. 4 (that is, the secondary winding wound around each primary winding corresponding to each phase). It is a figure for demonstrating the magnetic field coupling | bonding in 5 things). Also in the form of the figure, the magnetic flux B1 due to the primary winding is widely distributed with respect to the iron core, whereas the magnetic flux S2x, S2y, S2z of the secondary winding connected to a specific output channel is a coil structure. Is distributed locally to the iron core. For this reason, for example, when the X channel as the output channel is selected, the output voltage of the secondary winding corresponding to the other channel increases as in the example of FIG.

  Such an increase in the output voltage of the secondary winding Sz is not a normally intended operation and makes the output voltage unstable. In the gradient magnetic field power supply device of the magnetic resonance imaging apparatus, an interlock at the value of the output voltage is provided for circuit protection in the subsequent stage. Therefore, when the width of the voltage fluctuation is large and the voltage value exceeds the interlock threshold value, imaging cannot be performed. Such a problem occurs, for example, when a large power supply is performed in a specific axial direction (in the example of FIG. 7, the readout (RO) direction) represented by echo planar imaging (EPI) as shown in FIG. Is particularly conspicuous because the bias between the secondary windings for each axis of the current flowing to the secondary winding side becomes large.

  Here, echo planar imaging refers to applying a high frequency pulse for excitation and simultaneously applying a gradient magnetic field for slice (SE axis) to selectively excite magnetization in the slice plane, and then applying a refocusing high frequency pulse. Then, the readout gradient magnetic field (RO axis) is switched and applied multiple times in the direction parallel to the slice plane, and at the same time, the phase end gradient magnetic field is parallel to the slice gradient magnetic field and orthogonal to the readout gradient magnetic field. It is an imaging sequence which applies (PE axis). If necessary, the refocusing high frequency pulse may not be applied.

  In addition, the imaging sequence for supplying a large power to a specific channel is naturally not limited to echo planar imaging. For example, other examples include fast Fourier method and diffusion weighted imaging. The fast Fourier method is different from the EPI method in that the phase encoding gradient magnetic field is applied in a pulse manner every time the readout gradient magnetic field is inverted. Diffusion-weighted imaging is a sequence in which MPG (Motion Probing Gradient) pulses are added to an EPI sequence. For example, when the spin echo type EPI method is used, MPG pulses are added before and after a refocusing high-frequency pulse.

  In order to realize more suitable imaging in these imaging sequences and the like, in the secondary winding arrangement according to the second embodiment, the secondary winding of each phase with respect to each primary winding corresponding to each phase. The wires are arranged in a spatially dispersed manner so that secondary windings that generate a magnetic field in each channel do not concentrate.

  FIG. 8 shows an example of a transformer in which secondary windings corresponding to each channel are dispersedly arranged when, for example, five secondary windings are wound around the primary winding U phase. As shown in the figure, the secondary windings S1, S7, S13, S4 and S10 are for the X channel, and the secondary windings S6, S12, S3, S9 and S15 are for the Y channel and the secondary windings S11 and S2. , S8, S14, and S5 are connected to the Z channel, respectively. That is, the plurality of secondary windings corresponding to the output of each channel are arranged so as to be mixed in the core direction (axial direction) D1 of the iron core with respect to each primary winding corresponding to each phase ( At least one secondary winding corresponding to the output of each channel is arranged in the core direction D1). A plurality of secondary windings corresponding to the output of each channel are also arranged so as to be mixed in the concentric direction D2 (at least one secondary winding corresponding to the output of each channel is arranged in the concentric direction D2). Will be).

  When such an arrangement / connection form is adopted, the magnetic flux B2x on the secondary winding side when the output channel is the X channel, the magnetic flux B2y on the secondary winding side when the output channel is the Y channel, and the output channel The magnetic flux B2z on the secondary winding side when is a Z channel is as shown in FIGS. 9A, 9B, and 9C, respectively. Therefore, the leakage magnetic flux between the secondary windings corresponding to each output channel can be leveled in the core line direction D1, and the portion where the magnetic coupling is weak can be leveled. As a result, it is possible to provide a stable gradient magnetic field power supply output with little fluctuation in output voltage even if the output current is uneven between the output channels.

(effect)
According to the configuration described above, the following effects can be obtained.

  According to the present magnetic resonance imaging apparatus, the number of phases of the primary winding and the secondary winding of the transformer used in the gradient magnetic field power supply device are the same, and each secondary winding for each phase of the primary winding. Adopted a configuration with phases wound. Therefore, even if the output current and the output voltage are uneven between the output channels, it is possible to prevent the load from being biased to each primary winding corresponding to each phase. As a result, the power secured by each phase of the primary winding for each output channel can be leveled, and the power can be shared more stably than in the past.

  Further, according to the present magnetic resonance imaging apparatus, for each primary winding corresponding to each phase, the number of secondary windings corresponding to the output of each channel is substantially equivalent in the concentric direction, The electric power secured by the primary winding of each phase with respect to the secondary winding corresponding to each output can be leveled. As a result, even when the output current is uneven between the output channels, the load of the primary winding is not uneven, and a stable secondary voltage can be supplied.

  Further, according to the present magnetic resonance imaging apparatus, at least one secondary winding corresponding to each channel is arranged in the core direction D1 with respect to each primary winding corresponding to each phase, and the concentric direction D2 At least one secondary winding corresponding to each channel is arranged. Therefore, the leakage magnetic flux between the secondary windings corresponding to the output channel can be leveled in the direction of the core line, and the portion where the magnetic coupling is weak can be leveled. As a result, it is possible to provide a stable gradient magnetic field power supply output with little fluctuation in output voltage even if the output current is uneven between the output channels.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 1 ... Magnetic resonance imaging device, 11 ... Static magnetic field magnet, 12 ... Cooling system control part, 13 ... Gradient magnetic field coil, 14 ... High frequency transmission coil, 15 ... High frequency reception coil, 17 ... Gradient magnetic field power supply device, 18 ... Transmission part, DESCRIPTION OF SYMBOLS 19 ... Reception part, 20 ... Data processing part, 24 ... Display part, 171 ... Transformer, 173 ... Rectifier, 175x ... Xch output circuit, 175y ... Ych output circuit, 175z ... Zch output circuit, 177 ... Control circuit.

Claims (3)

By supplying a current from the gradient magnetic field power supply device to each gradient magnetic field coil corresponding to each axial direction of the spatial coordinate axis, a magnetic field that forms a gradient magnetic field in which the magnetic field changes along each direction of the spatial coordinate axis direction in the static magnetic field space. In the resonance imaging device,
The gradient magnetic field power supply device, one a transformer supplied to the current output circuit by winding a plurality of secondary windings supplied power to the phase of the phase number said primary winding of said secondary winding is a natural number times the number, for each phase of the primary winding, the secondary winding of each same number of phases are wound, as each phase of the secondary windings, each axis direction of the space coordinate axis have the corresponding output channels is wound, a plurality of said secondary winding of said output channels for the same said axial direction in the plurality of secondary windings of said output channels in each phase of the primary winding , the phases to be have you to one even without least Chi sac core direction and the concentric direction of the primary winding corresponding, are disposed separately across the secondary winding for the other of said axial transformer Magnetic resonance imaging apparatus having an instrument. In case of executing the echo planar imaging, among the secondary winding of each phase that is pre-Sharing, ABS location, with each phase of the secondary winding corresponding to the output channel corresponding to the reading direction, each axial 2. The magnetic resonance imaging apparatus according to claim 1, further comprising control means for supplying a current to each gradient magnetic field coil corresponding to. Used in a magnetic resonance imaging apparatus for forming a gradient magnetic field in which a magnetic field changes along each direction in the spatial coordinate axis direction in a static magnetic field space by supplying current to each gradient magnetic field coil corresponding to each axial direction of the spatial coordinate axis A gradient magnetic field power supply device,
A transformer for supplying the current output circuit power supplied to the primary winding of a plurality of secondary windings, the number of phases of the secondary winding is a natural number multiple of the number of phases of the primary winding , for each phase of the primary winding, the secondary winding of each same number of phases are wound, as each phase of the secondary winding, the output channels corresponding to the respective axial direction of the space coordinate axis winding have him, a plurality of secondary windings of said output channels in each phase of the primary winding, while the contact even without least Chi sac core direction and the concentric direction of the primary winding corresponding to the phases And the gradient magnetic field power supply device which has the transformer arrange | positioned separately on both sides of the secondary winding regarding the said other axial direction .