Weekday Educational Course Everything You Wanted to Know About Magnetic Susceptibility & Why It Is Important: Major Sources of Phase Contrast in the Brain Thursday 15 May 2014
نویسنده
چکیده
Highlights Gradient-echo MRI phase contrast depends on the underlying tissue magnetic susceptibility but is orientation-dependent and non-local. Calculating tissue magnetic susceptibility maps overcomes the orientation-dependent and non-local nature of phase contrast. Phase and susceptibility are primarily affected by tissue composition. For example, tissues rich in ferritin (stored iron) are relatively paramagnetic and show strong contrast in phase images and susceptibility maps. Tissue structure is also a major source of phase and susceptibility contrast, with orientationdependent effects arising at several different scales from macroscopic to microscopic and anisotropic susceptibility originating from ordered molecular structure. Susceptibility is not the whole story: chemical exchange-induced frequency shifts have been observed in brain tissue with lipids and proteins postulated as contributors. Different contrast sources dominate in different brain regions and in different pathologies
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WEEKDAY EDUCATIONAL COURSE Everything You Wanted to Know about Magnetic Susceptibility & Why It Is Important
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