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Abstract #2403

Spatially-Variant B0 Field Gradients in the Liver: Implications for R2* Mapping for Iron Quantification

Debra E. Horng1, 2, Diego Hernando1, Jens-Peter Khn, 13, Scott B. Reeder1, 2

1Radiology, University of Wisconsin-Madison, Madison, WI, United States; 2Medical Physics, University of Wisconsin-Madison, Madison, WI, United States; 3Radiology and Neuroradiology, Ernst Moritz Arndt University Greifswald, Greifswald, Germany

R2* relaxometry is a promising technique for liver iron quantification. However, measured R2* values are affected by the presence of macroscopic B0 inhomogeneities due to susceptibility effects. Susceptibility effects are modeled and measured to describe the B0 distribution. Fieldmaps are measured, and simulated from susceptibility distributions (including air/water/fat) derived from patient data. Segments 4A, 7 and 8 (near dome) exhibit rapid field variation along ẑ, both in measured and simulated field maps. Sagittal acquisitions may be preferable to axial if R2* measures near the liver dome are required. These methods may be used to optimize R2* mapping acquisitions for liver iron quantification.

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