Magnetic resonance imaging apparatus and method for control thereof

Patent metadata

Field	Value
Publication number	US-2016209484-A1
Application number	US-201614995393-A
Country	US
Kind code	A1
Filing date	Jan 14, 2016
Priority date	Jan 19, 2015
Publication date	Jul 21, 2016
Grant date	—

Abstract

In a magnetic resonance (MR) imaging apparatus and control method therefor, multiple frequency spectra of a material of the examination object are detected using at least one radio-frequency coil of and MR scanner, the coil having a number of coil elements and at least two of the frequency spectra are detected individually detected by respective, different coil elements. A number of resonant frequencies of at least one molecule in the material are established in the number of frequency spectra. Control information is formulated based on the number of resonant frequencies. The magnetic resonance scanner is controlled using the control information.

First claim

We claim as our invention:

1 . A method for controlling a magnetic resonance (MR) apparatus comprising an MR scanner comprising at least one radio-frequency (RF) coil comprising a plurality of coil elements, said method comprising:
operating the MR scanner to detect multiple frequency spectra of a material of an examination subject situated in the MR scanner, using said at least one radio-frequency coil, by detecting at least two frequency spectra of said multiple frequency spectra individually with respective, different coil elements of said plurality of coil elements; providing the detected frequency spectra to a computer and, in said computer, determining, in said multiple frequency spectra, multiple resonant frequencies of at least one molecule of said material; in said computer, using said multiple resonant frequencies to formulate control information designed to operate said MR scanner; and emitting an electronic signal, in which said control information is represented, in a signal format for operating said MR scanner.

2 . A method as claimed in claim 1 comprising, in said computer, merging said multiple resonant frequencies into one resulting resonant frequency of said at least one molecule, and formulating said control information as frequency adjustment control information to implement a frequency adjustment of said MR scanner using said resulting resonant frequency.

3 . A method as claimed in claim 1 wherein said MR scanner comprises a basic field magnet that produces a basic magnetic field, and wherein said method comprises:
in said computer, determining a distribution of values of said multiple resonant frequencies;
from said distribution of values of said multiple resonant frequencies, determining a measure of a homogeneity of said basic magnetic field; and
formulating said control information dependent on said measure of homogeneity of said basic magnetic field.

4 . A method as claimed in claim 3 comprising formulating said control information based on said measure of said homogeneity of said basic magnetic field to include output information dependent on said homogeneity, and displaying said output information visually to operating personnel of said MR scanner.

5 . A method as claimed in claim 3 comprising generating said control information dependent on said homogeneity of said basic magnetic field to include shim control information for shimming said MR scanner.

6 . A method as claimed in claim 1 wherein said MR scanner comprises a basic field magnet that produces a basic magnetic field in said MR scanner, and wherein said method comprises:
in said computer, calculating a spatial distribution of a strength of said basic magnetic field that includes information designating a spatial arrangement of said plurality of coil elements; and
formulating said control information using said calculated spatial distribution of the strength of the basic magnetic field.

7 . A method as claimed in claim 6 comprising calculating said spatial distribution of the strength of the basic magnetic field to include an allocation of local magnetic field strengths calculated from said multiple resonant frequencies, to a plurality of spatial support points that are respectively assigned to said plurality of coil elements.

8 . A method as claimed in claim 7 comprising formulating said control information using said calculated spatial distribution of the strength of the basic magnetic field to include a calculation of shim settings, using said support points, to operate shim coils of said MR scanner.

9 . A method as claimed in claim 1 comprising:
in said computer, giving respective resonant frequencies in said multiple resonant frequencies respective weighting factors, with at least one weighting factor of at least one resonant frequency in said multiple resonant frequencies being defined dependent on at least one characteristic of at least one frequency spectrum in said multiple frequency spectra; and
formulating said control information with said multiple resonant frequencies being weighted with said respective weighting factors.

10 . A method as claimed in claim 1 comprising:
in said computer, weighting respective resonant frequencies in said multiple resonant frequencies with respective weighting factors, and determining a weighting factor of at least one resonant frequency in said multiple resonant frequencies dependent on a deviation of said at least one resonant frequency from other resonant frequencies in said multiple resonant frequencies; and
formulating said control information with said multiple resonant frequencies being respectively weighted with said respective weighting factors.

11 . A method as claimed in claim 1 comprising detecting said multiple frequency spectra by detecting a first number of frequency spectra, and formulating said control information using a second number of said multiple resonant frequencies, wherein said first number is larger than said second number.

12 . A magnetic resonance (MR) apparatus comprising:
an MR scanner comprising at least one radio-frequency (RF) coil comprised of a plurality of coil elements; a control computer configured to operate the MR scanner to detect multiple frequency spectra of a material of an examination subject situated in the MR scanner, using said at least one radio-frequency coil, by detecting at least two frequency spectra of said multiple frequency spectra individually with respective, different coil elements of said plurality of coil elements; said control computer being configured to determine, in said multiple frequency spectra, multiple resonant frequencies of at least one molecule of said material; said control computer being configured to use said multiple resonant frequencies to formulate control information designed to operate said MR scanner; and said control computer being configured to emit an electronic signal, in which said control information is represented, to said MR scanner, and to operate said MR scanner according to said control information.

13 . A non-transitory, computer-readable data storage medium encoded with programming instructions, said storage medium being loaded into a control computer of a magnetic resonance (MR) apparatus that comprises an MR scanner comprising at least one radio-frequency (RF) coil comprising a plurality of coil elements, said programming instructions causing said control computer to:
operate the MR scanner to detect multiple frequency spectra of a material of an examination subject situated in the MR scanner, using said at least one radio-frequency coil, by detecting at least two frequency spectra of said multiple frequency spectra individually with respective, different coil elements of said plurality of coil elements; determine, in said multiple frequency spectra, multiple resonant frequencies of at least one molecule of said material; use said multiple resonant frequencies to formulate control information designed to operate said MR scanner; and emit an electronic signal, in which said control information is represented, from said control computer in a signal format for operating said MR scanner.

Assignees

• Siemens Ag

Inventors

• Bauer Simon
• Campagna Swen
• Hoelscher Uvo
• Niederloehner Daniel
• Paul Dominik

Classifications

• G01R33/583

  Calibration of signal excitation or detection systems, e.g. for optimal RF excitation power or frequency (G01R33/246 takes precedence) · CPC title

• G01R33/56563

  caused by a distortion of the main magnetic field B0, e.g. temporal variation of the magnitude or spatial inhomogeneity of B0 (G01R33/56509, G01R33/56518, G01R33/56536 take precedence) · CPC title

• G01R33/3875

  using correction coil assemblies, e.g. active shimming · CPC title

• G01R33/3664

  Switching for purposes other than coil coupling or decoupling, e.g. switching between a phased array mode and a quadrature mode, switching between surface coil modes of different geometrical shapes, switching from a whole body reception coil to a local reception coil or switching for automatic coil selection in moving table MR or for changing the field-of-view (G01R33/3671 takes precedence) · CPC title

• G01R33/243

  Spatial mapping of the polarizing magnetic field · CPC title