Unlock instant, AI-driven research and patent intelligence for your innovation.

Magnetic resonance image device

A magnetic resonance imaging and nuclear magnetic resonance technology, applied in the field of MRI, can solve the problems that the phase encoding value cannot be returned, the image quality is degraded, and the phase does not match.

Inactive Publication Date: 2005-06-01
GE YOKOGAWA MEDICAL SYST LTD
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Also due to the existence of inversion gradients gzr(i+1), gzr(i+2), ..., the phase encoding value cannot return to "0"
Therefore, this will interfere with the phase of later echoes
[0023] In addition, since the phase of the second echo SE2, which is very important for determining the contrast of the image, does not match the phase of the second stimulated echo STE2 generated simultaneously with the second echo SE2, artifacts appear on the image. elephant
[0024] However, the prior art proposed in the above-mentioned Japanese Patent Laid-Open No. 6-245917 has a problem that it is not sufficient to prevent degradation of image quality due to eddy currents and residual magnetism caused by phase encoding gradients.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Magnetic resonance image device
  • Magnetic resonance image device
  • Magnetic resonance image device

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0107] Fig. 6 is a block diagram showing the MRI apparatus of the first embodiment of the present invention.

[0108] The MRI apparatus 100 includes: a magnet assembly 1 having a space region (such as a cavity) for inserting an object or sample to be detected, surrounding the space region, a permanent magnet 1p for applying a predetermined main magnetic field to the sample, and a permanent magnet 1p for applying a predetermined main magnetic field to the sample. A gradient magnetic field coil 1g for generating or generating a gradient magnetic field in the direction of the slice axis, the direction of the phase encoding axis, and the direction of the sagittal plane axis (read axis), for sending an RF pulse for exciting the spins of the atomic nuclei in the sample A transmitting coil 1t, and a receiving coil 1r for detecting NMR signals from the sample. The gradient magnetic field coil 1g, the transmitting coil 1t, and the receiving coil 1r are electrically connected to the gra...

no. 2 example

[0138] The second embodiment is an improvement of the first embodiment. The phase-encoding axis correction component qi is obtained by the method equal to the time-integrated value of the first embodiment. However, the image data is in accordance with Figure 12 The pulse sequence Cp shown in the Figure 11 The pulse sequence shown in Bp was acquired.

[0139] That is, if Figure 12 As shown, an inversion gradient gyr(i) equivalent to the aforementioned basic component gy(i) is applied in the direction of the phase encoding axis, and a correction component qi equivalent to the aforementioned phase encoding axis is applied in the direction of the phase encoding axis Auxiliary inversion gradient gqr(i).

[0140] Even if an image is formed of the image data acquired in the above-mentioned manner, it is possible to prevent the image quality from deteriorating due to the interference of eddy current or residual magnetism caused by the phase encoding gradient.

no. 3 example

[0142] The third embodiment is an improvement of the first embodiment. The phase-encoding axis correction component qi is obtained by the method equal to the time-integrated value of the first embodiment. However, the new phase encoding gradient gy(i)' is determined using the basic component gy(i) of the phase encoding gradient derived from the scan parameters and the phase encoding axis correction component qi. Afterwards, the image data are acquired according to the pulse sequence Dp applied in a high-speed SE method using Figure 13 The new phase encoding gradient gy(i)' shown in .

[0143] Even if an image is formed of the image data acquired in the above-mentioned manner, it is possible to prevent the image quality from deteriorating due to the eddy current or residual magnetism caused by the phase encoding gradient.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The present invention relates to an MRI apparatus capable of preventing image quality from being degraded by eddy current or residual magnetic interference caused by a phase encoding gradient. An NMR signal is received while transmitting an RF pulse P1, applying a phase encoding gradient gy(i) in a coronal axis direction and a read gradient rr in a sagittal axis direction, and then applying An inverted gradient gyr(i)'. The reverse gradient gyr(i)' is defined as "(the basic component of opposite polarity whose time integral value is equal to the time integral value of the phase encoding gradient gy(i))+(used to correct the phase encoding gradient gy(i) ) caused by eddy currents or coronal axis correction components of residual magnetic interference)".

Description

technical field [0001] The present invention relates to an MRI (Magnetic Resonance Imaging Apparatus), and more particularly, to an MRI apparatus capable of preventing deterioration of image quality due to eddy currents and remanence caused by phase encoding gradients. Background technique [0002] figure 1 A pulse sequence applied in a conventional high-speed SE (spin echo) method is shown. [0003] In the pulse sequence K P In , an excitation pulse R and a chip selection gradient ss are applied. Then apply a first inversion or phase inversion pulse P1 and a chip selection gradient ss, and apply a phase encoding gradient gy(i) in the direction of the phase encoding axis. Thereafter, a nuclear magnetic resonance (NMR) signal is received from the first echo SE1 while applying a read gradient rr in the direction of the read axis. Next, an inversion gradient gyr(i) with opposite polarity is applied in the direction of the phase encoding axis, and the time integral value of ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): G01R33/20G01R33/48A61B5/055G01R33/565
CPCG01R33/56518G01R33/56527G01R33/56563G01R33/565
Inventor T·后藤
Owner GE YOKOGAWA MEDICAL SYST LTD