title: Reducing localized signal fluctuation in fMRI using spectral-spatial fat saturation.
abstract: Conventional 1D, spatially nonselective fat saturation can generate uncrushed fat signals in areas far outside the imaging slice where crushers are weak because of reduced gradient linearity. These fat signals can corrupt in-slice water signal, and in functional MRI, they can manifest themselves as artifacts such as clouds in image background or localized signal fluctuation over time. In this article, a spectral-spatial radiofrequency pulse is proposed to replace the conventional, spatially nonselective fat saturation pulse. The advantage of the proposed method is that fat protons far outside the image slice would not be excited because of the spatial selectivity, thereby removing the root cause of the fat aliasing artifacts. The proposed method also preserves thin slice capability, pulse duration, and fat suppression performance of the conventional method. Bloch simulation and human volunteer results show that the method is effective in reducing the fat aliasing artifacts seen in functional MRI.
authors.affiliation: Applied Science Laboratory, General Electric Healthcare, Milwaukee, Wisconsin 53188, USA. Dan.Xu@ge.com
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
authors.forename: R Scott
authors.initials: RS
authors.lastname: Hinks
authors.forename: Kevin F
authors.initials: KF
authors.lastname: King
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D013382:Subtraction Technique