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Magnetic resonance imaging apparatus

A technology of magnetic resonance imaging and gradient magnetic field, which is used in measurement devices, measurement of magnetic variables, medical science, etc.

Active Publication Date: 2015-05-20
TOSHIBA MEDICAL SYST CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The storage unit stores eddy current correction parameters for correcting the influence of the eddy current magnetic field for each captured position.

Method used

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no. 1 Embodiment approach

[0021] The magnetic resonance imaging apparatus (hereinafter, MRI (Magnetic Resonance Imaging) apparatus) according to the first embodiment prepares eddy current correction parameters for each imaging position, and corrects the waveform of the gradient magnetic field according to the position. Hereinafter, after briefly describing the configuration of the MRI apparatus according to the first embodiment, eddy current correction in the first embodiment will be described in detail.

[0022] figure 1 It is a block diagram showing the configuration of the MRI apparatus 100 according to the first embodiment. The static field magnet 1 is formed in a hollow cylindrical shape, and generates a uniform static magnetic field in the inner space. The static field magnet 1 is, for example, a permanent magnet, a superconducting magnet, or the like. The gradient magnetic field coil 2 is formed in a hollow cylindrical shape, and generates a gradient magnetic field in the inner space. Specifi...

no. 2 Embodiment approach

[0057] The MRI apparatus 100 according to the second embodiment has the same configuration as that of the first embodiment except for the matters described below. Figure 8 It is a block diagram showing the configuration of the sequence control unit 10 according to the second embodiment.

[0058] Figure 8 As shown, the sequence control unit 10 according to the second embodiment has a plurality of eddy current correction (short time constant) calculation units 12d for each “short time constant parameter” in the eddy current correction unit 12 . And, each eddy current correction (short time constant) calculation unit 12d separately performs calculation using the corresponding "short time constant parameter".

[0059] In the first embodiment, the calculation by the eddy current correction (short time constant) calculation unit 12d receives a control signal for outputting an ideal waveform from the gradient magnetic field output unit 11a, and starts after the "short time constan...

no. 3 Embodiment approach

[0066] The MRI apparatus 100 according to the third embodiment has the same configuration as that of the first embodiment except for the matters described below. Figure 9 It is a block diagram showing the configuration of the sequence control unit 10 according to the third embodiment.

[0067] Such as Figure 9 As shown, the sequence control unit 10 according to the third embodiment stores the “long time constant parameter” for each imaging position in the long time constant parameter storage unit 12a. That is, in the first and second embodiments, the long-time constant eddy current correction parameter is a parameter common to all positions. In the third embodiment, different parameters are used for the long-time constant eddy current correction parameters for each imaging position.

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Abstract

The magnetic resonance imaging apparatus according to the present embodiment includes a storage unit, an eddy current correcting unit, and a gradient magnetic field power supply. The storage unit stores therein eddy current correction parameters that each correspond to the imaging positions to correct the influence of an eddy current magnetic field. The eddy current correcting unit receives the waveform of the gradient magnetic field calculated in accordance with the imaging condition, performs calculation onto the received waveform of the gradient magnetic field by use of an eddy current correction parameter selected in accordance with the position, and outputs the corrected waveform obtained as the calculation result to the gradient magnetic field power supply. The gradient magnetic field power supply receives the corrected waveform and applies a gradient magnetic field in accordance with the corrected waveform.

Description

[0001] This application claims the priority of Japanese Patent Application No. 2011-049310 filed on March 7, 2011, and uses the entire content of the above-mentioned Japanese Patent Application in this application. technical field [0002] Embodiments relate to a magnetic resonance imaging apparatus. Background technique [0003] A magnetic resonance imaging apparatus provides positional information to magnetic resonance signals emitted from a subject by applying a gradient magnetic field, and reconstructs an image based on the positional information. [0004] However, the magnetic resonance imaging apparatus applies the gradient magnetic field in a pulsed manner. Therefore, eddy currents are generated in conductors (such as heat shields of static field magnets) that exist around the gradient magnetic field coil (coil), and a magnetic field (hereinafter, eddy current magnetic field) is generated by the generated eddy currents. . Since this eddy current magnetic field acts ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): A61B5/055
CPCG01R33/3852
Inventor 山中正昭
Owner TOSHIBA MEDICAL SYST CORP