Method of producing a compact control module for a high frequency antenna for a nuclear magnetic resonance imaging device

Patent metadata

Field	Value
Publication number	US-9562957-B2
Application number	US-201214233936-A
Country	US
Kind code	B2
Filing date	Jul 6, 2012
Priority date	Jul 20, 2011
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A method of making a compact control module of a high frequency antenna for a magnetic resonance imaging device including M control elements and N radiating elements, N greater than M, the control module represented by a control matrix {tilde over (P)}, approximately equal to a control matrix P to control the radiating elements, the method including: decomposing the control matrix {tilde over (P)} into a product of two matrices H×L; the matrix L with dimensions M×M capable of transforming M signals V m transmitted by M control elements into M signals V l , in amplitude and in phase; the matrix H with dimensions N×M receiving the M signals V l as inputs; producing the matrix FI with a number of stages less than a number of stages necessary for implementation of the matrix P; and using the matrix L starting from implementation of the matrix H determined during the producing.

First claim

The invention claimed is:

1. Method of making a compact control module of a high frequency antenna for a magnetic resonance imaging device comprising a plurality M of control elements and a plurality N of radiating elements, said plurality N of radiating elements being greater than said plurality M of control elements, said control module being represented by a control matrix {tilde over (P)}, where {tilde over (P)} is a matrix approximately equal to a control matrix P to control said plurality N of radiating elements using said plurality M of control elements; said method comprising:
decomposing the approximate control matrix {tilde over (P)} into a product of two matrices H×L; the first matrix L with dimensions M×M being capable of transforming a plurality M of signals V m transmitted by said plurality M of control elements into M signals V l , in amplitude and in phase; the second matrix H with dimensions N×M receiving said M signals V l , as inputs;
producing said matrix H with a number of stages less than a number of stages necessary for implementation of the control matrix P, said stages being implemented by coupling means, phase shifting means and permutation means;
using said matrix L by software means starting from implementation of said matrix H determined during the producing.

2. Method of making a control module of a high frequency antenna for a magnetic resonance imaging device according to claim 1 , wherein said implemented matrix H comprises a number of stages K less than:
E sup (ln( N )/ln(2)), where
E sup corresponds to the next higher integer part
N corresponds to the number of radiating elements of the antenna;
“ln” corresponds to the Naperian logarithm.

3. Method of making a control module of a high frequency antenna for a magnetic resonance imaging device according to claim 1 , comprising decomposing the matrix H into a plurality K+1 of matrices S according to the following relation:
H=S K ,S k−1 , . . . ,S 1 S 0
where: S 0 is a matrix with dimensions N×M
S k is a matrix with dimensions N×N where k={1, . . . , K}.

4. Method of making a control module of a high frequency antenna for a magnetic resonance imaging device according to claim 3 , wherein each of said matrices S k where k={1, . . . , K} is formed by the matrix product of a coupling matrix C k , a phase shift matrix Φ k and a permutation matrix Π k such that a signal X k+1 at the output from stage k of the control module depends on the relation:
X k+1 =S k X k =Π k Φ k C k X k ,

where X k represents the input signal to said stage k.

5. Method of making a control module of a high frequency antenna for a magnetic resonance imaging device according to claim 4 , wherein said coupling matrix C k is implemented by said coupling means, said phase shift matrix Φ k is implemented by said phase shift means, and said permutation matrix Π k is implemented by said permutation means.

6. Method of making a control module of a high frequency antenna for a magnetic resonance imaging device according to claim 5 , wherein said coupling means are universal hybrid couplers.

7. Method of making a control module of a high frequency antenna for a magnetic resonance imaging device according to claim 5 , wherein said coupling means are universal 6 dB hybrid couplers.

8. Control module obtained by the manufacturing method according to claim 1 , comprising an arrangement of coupling means, phase shift means and permutation means and software means such that said N signals V a output from said control module depend on the relation:
V a =HLV m
where
V m represents the M input signals to said control module;
H is the matrix with dimensions N×M that can be implemented by said coupling means, said phase shift means and said permutation means;
L is the matrix with dimensions M×M that can be used by said software means.

Assignees

• Ferrand Guillaume
• Luong Michel
• Commissariat Energie Atomique

Inventors

• Ferrand Guillaume
• Luong Michel

Classifications

• Y10T29/49016

  Antenna or wave energy "plumbing" making · CPC title

• G01R33/34

  Constructional details, e.g. resonators {, specially adapted to MR} · CPC title

• G01R33/5612

  Parallel RF transmission, i.e. RF pulse transmission using a plurality of independent transmission channels · CPC title

• G01R33/36 Primary

  Electrical details, e.g. matching or coupling of the coil to the receiver · CPC title

• G01R33/3415

  comprising arrays of sub-coils {, i.e. phased-array coils with flexible receiver channels} · CPC title