Correction device, correction method, and magnetic resonance imaging apparatus

Patent metadata

Field	Value
Publication number	US-2018100909-A1
Application number	US-201715693322-A
Country	US
Kind code	A1
Filing date	Aug 31, 2017
Priority date	Oct 11, 2016
Publication date	Apr 12, 2018
Grant date	—

Abstract

According to one embodiment, a correction device is used for an apparatus including a coil and a conductor in a vicinity of the coil. The correction device corrects an influence of a magnetic field generated by the conductor when a current flows through the coil. The correction device includes a first measuring device, a second measuring device, and a control device. The first measuring device measures a first signal of the coil. The second measuring device measures a second signal of the coil, which is different from the first signal. The control device estimates the influence acting on the coil, based on a difference between the first signal filtered by a first filter and the second signal filtered by a second filter. Furthermore, the control device controls a command signal for flowing the current to the coil, based on an estimation result of the influence.

First claim

What is claimed is:

1 . A correction device used for an apparatus including a coil and a conductor in a vicinity of the coil, and for correcting an influence of a magnetic field generated by the conductor when a current flows through the coil,
the correction device comprising: a first measuring device that measures a first signal of the coil; a second measuring device that measures a second signal of the coil, which is different from the first signal; and a control device that estimates the influence of the magnetic field acting on the coil, based on a difference between the first signal filtered by a first filter and the second signal filtered by a second filter, and control a command signal for flowing the current to the coil, based on an estimation result of the influence of the magnetic field.

2 . The correction device according to claim 1 , wherein
the control device further includes an integrating circuit that integrates the difference between the filtered first signal and the filtered second signal.

3 . The correction device according to claim 2 , wherein
control device further includes a gain adjuster that multiplies a signal of the difference integrated by the integrating circuit, with a gain.

4 . The correction device according to claim 1 , wherein
the first filter filters a high frequency component of the first signal, and the second filter filters a low frequency component of the second signal.

5 . The correction device according to claim 1 , wherein
the control device obtains the estimation result, based on an inductance and a resistance value of the coil.

6 . The correction device according to claim 1 , wherein
the first measuring device is connected to a portion between the second measuring device and the coil.

7 . The correction device according to claim 1 , wherein,
in the case where the first signal is represented by v 1 , the second signal is represented by i 1 , the inductance of the coil is represented by L 1 , the resistance of the coil is represented by R 1 , the current flowing through the conductor is represented by i 2 , a mutual inductance of the coil and the conductor is represented by M 12 , the estimation result is expressed by following equation

M
12



di
2

dt

=

v
1

-

(

L
1



di
1

dt

+

R
1



i
1

)

.

8 . A correction method to be applied to a correction device used for an apparatus including a coil and a conductor in a vicinity of the coil and for correcting an influence of a magnetic field generated by the conductor when a current flows through the coil,
the correction method comprising: measuring a first signal of the coil; measuring a second signal of the coil, which is different from the first signal; estimating the influence of the magnetic field acting on the coil, based on a difference between the first signal filtered by a first filter and the second signal filtered by a second filter; and controlling a command signal for flowing the current to the coil, based on an estimation result of the influence of the magnetic field.

9 . A magnetic resonance imaging apparatus comprising:
the correction device according to claim 1 ; and at least one of a gantry and an image generation device.

Assignees

• Toshiba Kk

Inventors

• Takakura Shinji
• Yasunaka Shigen

Classifications

• G01R33/5608

  Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels (image data processing or generation, in general G06T) · CPC title

• H03F1/00

  Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements · CPC title

• G05B13/02

  electric · CPC title

• G01R33/56518 Primary

  due to eddy currents, e.g. caused by switching of the gradient magnetic field · CPC title

• G01R33/3852 Primary

  Gradient amplifiers; means for controlling the application of a gradient magnetic field to the sample, e.g. a gradient signal synthesizer · CPC title