US 6,552,541 B2 · Method of correcting disturbing influences on the MR signals of a substance disposed in the measuring volume of an MR apparatus

Abstract

A method of correcting disturbing influences on MR (=magnetic resonance) signals of a substance disposed in the measuring volume of an MR apparatus excited by one or more RF (=radio frequency) excitation pulses, wherein an RF excitation pulse is irradiated onto the substance and a time-dependent MR signal generated thereby is detected and digitized in a phase-sensitive fashion, wherein a time dependence (1)Δφi(ti) of the phase of an MR signal, relative to a predetermined reference phase φrefi(ti) of a reference signal Srefi(ti), is determined and digitized from a time dependence (1) si(ti) of the detected and digitized MR signal and one or more correction or controlled variables are determined therefrom. Nearly all measuring points are used for determination of the magnetic field deviation and thus for control to guarantee considerably improved control accuracy.

Claims31

Dependent claims

A method for correcting disturbing influences on magnetic resonance (MR) signals of a substance, the method comprising the steps of:

a) disposing the substance in a measuring volume of an MR apparatus;
b) irradiating at least one radio frequency (RF) excitation pulse onto the substance;
c) defining a predetermined reference signal having a predetermined reference phase time dependence within a duration of said reference signal;
d) detecting and digitizing, in a phase-sensitive fashion, an MR signal emanating from the substance in response to said excitation pulse, said MR signal having an MR signal phase time dependence within a duration of said MR signal;
e) determining a digitized time dependent phase difference Δφi(ti) between said MR signal phase and said predetermined reference signal phase;
and
f) extracting at least one time dependent correction variable from said phase difference.

4 more elements

An MR apparatus for correcting disturbing influences on magnetic resonance (MR) signals of a substance, the apparatus comprising:

means for disposing the substance in a measuring volume of an MR apparatus;
means for irradiating at least one radio frequency (RF) excitation pulse onto the substance;
means for defining a predetermined reference signal having a predetermined reference phase time dependence within a duration of said reference signal;
means for detecting and digitizing, in a phase-sensitive fashion, an MR signal emanating from the substance in response to said excitation pulse, said MR signal having an MR signal phase time dependence within a duration of said MR signal;
means for determining a digitized time dependent phase difference Δφi(ti) between said MR signal phase and said predetermined reference signal phase;
and
means for extracting at least one time dependent correction variable from said phase difference.

4 more elements

Dependencies are inferred from the claim text.

Method of correcting disturbing influences on the MR signals of a substance disposed in the measuring volume of an MR apparatus

Life of this patent

Method of correcting disturbing influences on the MR signals of a substance disposed in the measuring volume of an MR apparatus

Life of this patent

Abstract

Claims31