Patent ID: 8368400

Claim:
A magnetic resonance method that performs spatially selective excitation and refocusing of nuclear spins disposed within an object under investigation in order to generate a target distribution of magnetization of the nuclear spins from an initial distribution of magnetization of the nuclear spins, the method comprising the steps of: a) selecting a first distribution of magnetization, a sequence of radio frequency sub-pulses of independent duration, a main magnetic field aligned along a z-axis, magnetic field gradients and spatial and/or spectral resolution in order to perform spatially selective and frequency selective excitation as well as multi-dimensionally spatially selective excitation of the nuclear spins within the object; b) calculating, using a computer having a CPU, a change in the first distribution of magnetization caused by at least one large angle RF pulse (LAP) by complete, full integration of Bloch equations without any small angle approximation, the at least one LAP having a tip angle greater than or equal to 15 degrees in order to generate a second distribution of magnetization approximating a desired distribution of magnetization; c) calculating, using the computer having the CPU, at least one small angle RF pulse (SAP) having a tip angle of less than 15 degrees that uses the small angle approximation, the at least one SAP reducing a difference between the desired distribution of magnetization and the second distribution of magnetization caused by the at least one LAP as calculated in step b); d) establishing the main magnetic field and the field gradients selected in step a); e) disposing the object in the main magnetic field; f) exciting the nuclear spins in the object by irradiating, using RF coils, the at least one LAP calculated in step b); g) exciting the nuclear spins in the object by irradiating, using the RF coils, the at least one SAP calculated in step c), thereby, together with step f), substantially generating the target distribution of magnetization; and h) executing the magnetic resonance method with the substantially generated target distribution of magnetization in order to obtain a magnetic resonance image of the object under investigation.