Method of reconstructing a magnetic resonance image of an object considering higher-order dynamic fields

Abstract

The invention relates to a method of acquiring a magnetic resonance image of an object employing spatial encoding by a gradient field, said gradient field comprising non-linear gradient field components, the method comprising: selecting (100) a limited set of spatially variant basis functions for describing the gradient field including the non-linear gradient field components by linear combinations of said basis functions, determining (102) the temporally variant weights of the basis functions for said linear combinations, acquiring (104) magnetic resonance data of the object (10), - embedding (106) the acquired magnetic resonance data into a multidimensional space, wherein the number of dimensions is given by the number of selected basis functions, transforming (110) the acquired magnetic resonance data in this multidimensional space from the measurement domain to the image domain, - calculating (112) the desired magnetic resonance image of the object (10) from this transformed multi-dimensional space by linear combinations along the surplus dimensions.

Description

technical field [0001] Currently, image-forming MR methods, which utilize the interaction between magnetic fields and nuclear spins to form two-dimensional or three-dimensional images, are widely used, especially in the field of medical diagnostics, because for the imaging of soft tissues, the methods are in many ways Advantages over other imaging methods are that the method does not require ionizing radiation and is generally noninvasive. Background technique [0002] According to the usual MR methods, the body of the patient or, in general, the object to be examined is exposed to a strong, homogeneous magnetic field B 0 , while the direction of this magnetic field defines the axis of the coordinate system on which the measurement is based, typically the z-axis. [0003] The magnetic field produces different energy levels for each nuclear spin depending on the strength of the applied magnetic field. These nuclear spins can be excited (spin resonance) by applying an altern...

AI Technical Summary

Problems solved by technology

However, making no assumptions about the structure of the encoding matrix linking the acquired data to the unknown image will result in a very large system of linear equations

Solving this system of equations has hitherto remained unattainably complex for clinical applications

[0009] Furthermore, intentional use of non-constant gradients for spatial encoding has also recently been considered, which leads to similar problems in image reconstruction

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