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Universitätsklinikum Freiburg

Universit&auml;tsklinikum Freiburg

J&uuml;rgen Hennig

Klaus Scheffler

Oliver Speck

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.

Method for measuring the magnetic resonance (NMR) by steady state signals (SSFP)

Method of measuring the magnetic resonance (&equals;NMR) by means of spin echos

A method for magnetic resonance imaging (NMR) subjects a sample of magnetic spins, having differing Larmor frequencies and located in an external magnetic field, to a sequence of at least two radio frequency pulse sequences in time separation tm with respect to each other, wherein the difference in Larmor frequencies is due to the type of nuclei, to the inhomogeneities of the magnetic field utilized, or through action of an additional magnetic field gradient and wherein the first radio frequency pulse sequence effects excitation of, relative to the distribution of Larmor frequencies, periodic modulation of the z-magnetization having a modulation separation 2&Dgr;&ohgr; and the second radio frequency pulse sequence transfers this periodic modulating z-magnetization into transverse magnetization leading to signal production. The method is characterized in that at least one of the radio frequency pulse sequences utilized has a periodic rectangular excitation shape having a modulation separation 2&Dgr;&ohgr; so that, following a certain time determined by the modulation separation 2&Dgr;&ohgr;, at least a partial coherence of transverse magnetization results and thereby a measurable NMR signal. In this manner, an improved stimulated echo signal can be created.

Growing community of inventors

Freiburg, Germany

Jürgen Hennig

Growing community of inventors

Freiburg, Germany

J&uuml;rgen Hennig

Jürgen Hennig