Abstract #2660

Orientation Effects on the Local Magnetic Field or Phase & T2*-Weighted Hypointensity of Gradient Echo Imaging & Their Removal in Quantitative Susceptibility Mapping

Jianqi Li¹, Tian Liu^2,3, Deqi Cui^2,4, Qianfeng Wang¹, Mengchao Pei¹, Ming Zhang¹, Yi Wang^2,3

¹Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, People's Republic of; ²Radiology, Weill Medical College of Cornell University, New York, NY, United States; ³Biomedical Engineering, Cornell University, Ithaca, NY, United States; ⁴Biomedical Engineering,, Cornell University , Ithaca, NY, United States

GRE is a commonly used pulse sequence in MRI. Both T2*-weighted hypointensity and phase contrast in the GRE images depend on relative orientation with respect to B0, and on the relative geometry between observation voxel and susceptibility source. We here illustrate the orientation effects on the induced local field or phase, T2* hypointensity, susceptibility weighted imaging (SWI) and quantitative susceptibility mapping (QSM). The shapes measured by the magnitude image and SWI and the induced field pattern varied strong with the orientation w.r.t. B0 or the blooming artifacts were strongly orientation-depended. The QSM removed the blooming artifacts and the calculated shapes didnt depend on the orientations.