Method for generating a desired spatially variable temporal profile of the magnetization state in magnetic resonance
A method for generating a desired temporal profile of the magnetization state in an object under examination (O) during an experiment involving magnetic resonance is characterized in that at least one spatially dependent change in the magnetization state inside the object under examination (O) is predefined and spatially selective radio-frequency pulses, which allow a simultaneous and independent change in the magnetization state at locations with different stipulations, are irradiated in order to implement the predefined spatially dependent change in the magnetization state. The method permits establishment of the same desired temporal profile of the magnetization state for different regions of the object under examination despite different given experimental parameters or deliberate generation of different desired profiles of the magnetization state at different locations.
1. A method for generating a desired temporal profile of a magnetization state in an object under examination during an experiment involving magnetic resonance, wherein, during the experiment, the magnetization state is changed several times by means of radio-frequency pulses, with at least one sequence parameter, which influences a development of the magnetization state between two applications of radio-frequency pulses, being determined in advance, the method comprising the steps of:
a) predefining at least one spatially dependent change in the magnetization state inside the object under examination, wherein the at least one spatially dependent change is generated by means of a radio-frequency pulse, depends on the at least one sequence parameter, is different at at least two locations and is different from zero at those locations; and
b) irradiating spatially selective radio-frequency pulses, wherein the spatially selective radio-frequency pulses generate a simultaneous and independent change in the magnetization state at locations having different stipulations, thereby implementing the spatially dependent change in the magnetization state predefined in step a).
2. The method of claim 1 , wherein irradiation of radio-frequency pulses is combined with spatially and temporally varying additional magnetic fields, which are superimposed on a static and homogeneous magnetic basic field of a magnetic resonance measurement apparatus.
3. The method of claim 1 , wherein irradiation of the radio-frequency pulses is effected by means of at least two transmission elements of a transmission antenna device.
4. The method of claim 1 , wherein stipulations for the spatially dependent change in the magnetization state are additionally determined by given experimental parameters.
5. The method of claim 1 , wherein stipulated changes in the magnetization state are selected such that the temporal profile of the magnetization state reaches a dynamic steady state.
6. The method of claim 1 , wherein the method is used as part of an MR imaging experiment.
7. The method of claim 1 , wherein the method is used as part of an MR spectroscopy experiment.