Magnetization transfer phenomenon in the human brain at 7 T

详细信息    查看全文

• 作者：O.E. Mougin ; R.C. Coxon ; A. Pitiot ; P.A. Gowl
• 关键词：Magnetization transfer ; MT ; CEST ; APT ; Exchange ; Amide ; MRI ; NMR ; Phase contrast
• 刊名：NeuroImage
• 出版年：2010
• 出版时间：1 January 2010
• 年：2010
• 卷：49
• 期：1
• 页码：272-281
• 全文大小：1125 K

文摘

Magnetization transfer is an important source of contrast in magnetic resonance imaging which is sensitive to the concentration of macromolecules and other solutes present in the tissue. Magnetization transfer effects can be visualized in magnetization transfer ratio images or quantified via the z-spectrum. This paper presents methods of measuring the z-spectrum and of producing high-resolution MTR images and maps of z-spectrum asymmetry in vivo at 7 T, within SAR limits. It also uses a 3-compartment model to measure chemical exchange and magnetization transfer parameters from the z-spectrum data. The peak in the z-spectrum associated with chemical exchange between amide and water protons (amide proton transfer, APT, effects) is much more apparent at 7 T than at 3 T. Furthermore at 7 T quantitative APT results varied between the corpus callosum and other white matter structures, suggesting that quantitative APT imaging could be used as a method of measuring myelination. The results also suggest that chemical exchange is not responsible for the phase shift observed in susceptibility weighted images between grey matter and white matter.