| 摘要 |
Magnetic resonance (MR) data are acquired with a two-point Dixon technique in which a first spectral component and a second spectral component, for example, a water component and a fat component, are determined. A computation grid of lower resolution in comparison to the MR data is determined, wherein each grid point of the computation grid encompasses a predetermined number of adjacent image points of the MR data. A numerical optimization is implemented for each image point of the MR data, and the first spectral component and the second spectral component are calculated analytically based on the result of the numerical optimization. |
| 主权项 |
1. A method for acquiring magnetic resonance data from an examination subject, comprising:
operating a magnetic resonance data acquisition unit, that generates a basic magnetic field in which an examination subject is situated, according to a magnetic resonance data acquisition sequence in which magnetic resonance data are acquired from the examination subject at each of a first echo time and a second echo time that occur in said magnetic resonance data acquisition sequence, said magnetic resonance data acquired at each of said first echo time and said second echo time representing multiple image points of an image to be generated of the examination subject; providing said magnetic resonance data to a computerized processor and, in said computerized processor, operating on said magnetic resonance data with a spectral model of a two-point Dixon technique that relates said magnetic resonance data to a first spectral component and a second spectral component of said magnetic resonance data, and a phase of said magnetic resonance data at said first echo time, and a phase evolution of said magnetic resonance data that occurs due to at least one of field inhomogeneities in said basic magnetic field and eddy currents that occur in said magnetic resonance data acquisition unit between said first echo time and said second echo time; in said processor, computing a grid having a lower resolution than said image points, with each grid point of said grid encompassing a predetermined number of adjacent image points represented by said magnetic resonance data; in said processor, for each image point of said magnetic resonance data, implementing a numerical optimization that determines an optimization result selected from the group consisting of an optimization of said phase at said first echo time and an optimization of said phase evolution, with said optimization being implemented based on an equation based on at least one of said phase at said first echo time and said phase evolution being constant for said image points that are encompassed by a grid point of said grid; in said processor, analytically calculating said first spectral component and said second spectral component from said optimization result; and making the calculated first and second spectral components available in electronic form at an output of said processor in a format allowing reconstruction of an in-phase image and an out-of-phase image according to said two-point Dixon technique that is modeled by said spectral model. |
