Patent ID: 7262599
Filing Date: 2007-08-28
Classification: G01R

Abstract:
1. Method of obtaining magnetic resonance measurement data for the reproduction of an image of a volume of an object which is subjected to a constant main magnetic field B 0 in a longitudinal direction, illustrating the contrast between volume elements (voxels) of the image representation which differ from one another in the parameter vectors P i of the magnetic resonance property of the respective inherent substance i, wherein the object volume which is to be imaged is subjected to a sequence of repetitive blocks of effects, each containing an RF-pulse with a flip angle α<90°, in order to generate a measurable transversal magnetization, and magnetic field gradients in order to obtain in each block N≧1 location-coded measurement signals of the transversal magnetization for the image reconstruction and to achieve sufficient intravoxel dephasing of the transversal magnetization before the appearance of the next RF-pulse, and wherein the phase φ(k) of the RF-pulse is changed from block to block in accordance with the rule where k is the running index of the blocks within the sequence and φ is a randomly selected phase angle, wherein for the sequence parameter Φ a value Φ c is selected, in which the set {S ij } of the difference values is optimized in accordance with a selected criterion K ({S ij }), where n with 1≦n≦N is the running index of the measurement signal detected within a respective block, S n (Φ,Q,P i ) or S n (Φ,Q,P j ) is the value of the transversal magnetization of the voxels, which contain the substance i or j, in the condition of dynamic equilibrium at the point in time of the maximum of the nth measurement signal, Q stands for the values of the remaining sequence parameters, and {S ij } includes all desired pairs of substances i and j.