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Abstract #4522

Improved Cardiac Shim Using Field Map Estimate from Multi-Echo Dixon Method

Peter Kellman1, Diego Hernando2, Saurabh Shah3, Sven Zuehlsdorff3, Andreas Greiser4, Renate Jerecic3

1National Institutes of Health, Bethesda, MD, USA; 2University of Illinois, Urbana, IL, USA; 3Siemens Medical Solutions, Chicago, IL, USA; 4Siemens Medical Solutions, Erlangen, Germany

Rapid field variation across the heart cause by tissue-air interface presents a challenge to cardiac imaging. An improved method for shimming is presented which estimates the fieldmap in the presence of rapid field variation and in regions containing both fat and water. The fieldmap is estimated using a multi-echo GRE acquisition and VARPRO solution for fat and water components. The multi-echo GRE sequence was implemented with parallel imaging reconstruction as a real-time, free-breathing, non-ECG gated 2D multi-slice acquisition, acquiring the volume in <7s. With the proposed shim method, the field variation in the user defined heart region was reduced significantly.