Mri imaging using variable density spiral planar coil

Patent metadata

Field	Value
Publication number	US-2017003359-A1
Application number	US-201515125654-A
Country	US
Kind code	A1
Filing date	Mar 13, 2015
Priority date	Mar 14, 2014
Publication date	Jan 5, 2017
Grant date	—

Abstract

A system and method a for local coil system for performing a magnetic resonance imaging (MRI) process using an MRI system is provided. The local coil system includes a conductor extending in a spiral path along a single plane and forming a variable spiral extending from inner spirals proximate a center of the spiral path having a first density to outer spirals proximate a perimeter of the spiral path having a second density. The first density and the second density are different densities.

First claim

1 . A magnetic resonance imaging (MRI) system, comprising:
a magnet system configured to generate a static magnetic field about at least a region of interest (ROI) of a subject arranged in the MRI system; a plurality of gradient coils configured to establish at least one magnetic gradient field with respect to the static magnetic field; a radio frequency (RF) system including a local coil comprising:
a conductor extending in a spiral path along a single plane and forming a variable spiral extending from inner spirals of a first density and proximate a center of the spiral path to outer spirals of a second density and proximate a perimeter of the spiral path; and
wherein the first density and the second density are different densities.

2 . The MRI system of claim 1 wherein the first density is less than the second density.

3 . The MRI system of claim 1 wherein the static magnetic field is less than 10 mT.

4 . The MRI system of claim 1 wherein the spiral path includes one of 20 turns or 30 turns combined in series with a 20-turn loop located proximate the perimeter and configured to balance a magnetic field near the perimeter.

5 . The MRI system of claim 1 wherein the local coil is sized to image a periphery of the subject.

6 . The MRI system of claim 5 wherein the local coil extends in the signal plane to provide a circular field of view of 20 cm.

7 . The MRI system of claim 1 wherein the local coil is configured to produce flat magnetic field lines relative to the single plane.

8 . The MRI system of claim 7 wherein the flat magnetic field lines are formed 2 cm above the single plane and maintains below 40 percent field deviation at ±7.5 cm along the single plane.

9 . The MRI system of claim 1 wherein the local coil is configured to produce curved magnetic field lines relative to the single plane.

10 . The MRI system of claim 9 wherein the curved magnetic field lines Provide over 70 percent deviation at ±7.5 cm along the single plane

11 . A local coil system for performing a magnetic resonance imaging (MRI) process using an MRI system, the local coil system comprising:
a conductor extending in a spiral path along a single plane and forming a variable spiral extending from inner spirals proximate a center of the spiral path having a first density to outer spirals proximate a perimeter of the spiral path having a second density; and wherein the first density and the second density are different densities.

12 . The system of claim 11 further comprising a plurality of loops formed by the conductor along the perimeter of the spiral path.

13 . The system of claim 11 wherein the first density is less than the second density.

14 . The system of claim 11 where the spiral path is sized to image a periphery of the subject.

15 . The system of claim 14 wherein the spiral path extends in the single plane to provide a circular field of view of 20 cm.

16 . The system of claim 11 wherein the local coil is configured to produce flat magnetic field lines relative to the single plane.

17 . The system of claim 11 wherein the local coil is configured to produce curved magnetic field lines relative to the single plane.

18 . The system of claim 11 wherein the local coil maintains a constant area between each successive turn.

19 . The system of claim 11 wherein the spiral path is continuously variable from the inner spirals to the outer spirals.

20 . The system of claim 11 wherein the local coil is tuned to operate with a static magnetic field is less than 10 mT to carry out a magnetic resonance imaging process.

Assignees

• Massachusetts Gen Hospital

Inventors

• Rosen Matthew S
• Sarracanie Mathieu
• Paul Stanwix

Classifications

• G01R33/5635

  Angiography, e.g. contrast-enhanced angiography [CE-MRA] or time-of-flight angiography [TOF-MRA] · CPC title

• G01R33/5673

  Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker · CPC title

• G01R33/341 Primary

  comprising surface coils · CPC title

• G01R33/445

  MR involving a non-standard magnetic field B0, e.g. of low magnitude as in the earth's magnetic field or in nanoTesla spectroscopy, comprising a polarizing magnetic field for pre-polarisation, B0 with a temporal variation of its magnitude or direction such as field cycling of B0 or rotation of the direction of B0, or spatially inhomogeneous B0 like in fringe-field MR or in stray-field imaging · CPC title