Universitätsklinikum Freiburg

Universit&auml;tsklinikum Freiburg

Oliver Speck

Juergen Hennig

Klaus Scheffler

Jürgen Hennig

J&uuml;rgen Hennig

Maxim Zaitse

A magnetic resonance (NMR) method for fast, dynamic, spatially resolved measurement of the temporal changes in NMR signals by means of repeated data acquisition in individual measurements (Acq) with measuring sequences which are sensitive to a parameter to be observed, in an NMR apparatus with shim coils for correcting the magnetic field is characterized in that during data acquisition of each individual measurement (Acq) in acquisition steps (SS) with a time lag, the magnetic field distribution in the NMR apparatus is measured, technically or physiologically based changes in the magnetic field distribution are determined therefrom in a calculation step (S) as well as a change in the currents in the magnetic field required for compensation thereof, and the dynamic changes in the magnetic field distribution are compensated for by means of the correspondingly changed shim currents. The inventive method permits dynamic detection of the changes in the magnetic field distribution through the above-mentioned factors during the measurement and compensation thereof through corresponding re-calculation of &#x394;y(x,y,z) or &#x394;B(x,y,z) and adjustment of the shim currents to render the magnetic field distribution for subsequent measurements again preferably identical to the initial magnetic field distribution.

Method for dynamic detection and change in the magnetic field distribution in magnetic resonance (NMR) measurements

A nuclear magnetic resonance (NMR) tomography method for investigating a target object, wherein radio frequency (RF) pulses are irradiated into a target volume and/or RF pulses from the target volume are detected, wherein the target volume is determined by the frequency of the RF pulses and/or through magnetic field gradients, and wherein the target object is moved relative to the NMR tomograph during NMR data acquisition, is characterized in that the frequency of the RF pulses and/or the magnetic field gradients is/are changed during NMR data acquisition such that the target volume covered by the RF pulses is moved relative to the NMR tomograph at the same speed and direction of motion as the target object during NMR data acquisition. This provides a method for investigating a target object which moves relative to the NMR tomograph during NMR data acquisition, which can be carried out in a fast and simple manner.

Method for the acquisition of moving objects through nuclear magnetic resonance tomography

A method of magnetic resonance (NMR) for spatially resolved measurement of the distribution of NMR signals of metabolites (CSI) with low signal intensity, wherein on a spin ensemble, a sequence of radio frequency (RF) pulses is applied which are mutually offset by a time interval of a repetition time TR and magnetic gradient fields are switched of which at least one causes spatial encoding of the excited spins, is characterized in that the repetition time TR between the exciting RF pulses is selected to be at the most in the magnitude transverse relaxation time T2* of the spins to be excited, preferably approximately T2*/10 and that the magnetic gradient fields are selected such that their action integral is completely balanced over a repetition period of a time period TR such that NMR signal production is carried out according to the principle of steady state free precession (SSFP). This new method permits utilization of the advantages of SSFP methods also for spectroscopic recordings, in particular for chemical shift imaging.

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Freiburg, Germany

Oliver Speck