返回
New Phase-Based B1 Mapping Method Using Two-Dimensional Spin-Echo Imaging with Hyperbolic Secant Pulses
DOI:10.1002/mrm.25110.png)
摘要
En 中文
PurposeTo propose a new phase-based B-1-mapping method that exploits phase information created by hyperbolic secant (HS) pulses in conventional 2D spin-echo imaging. MethodsIn this B-1-mapping method, HS pulses are used to accomplish /2 excitation and refocusing in standard multislice spin-echo imaging. When setting the ratio of pulse lengths of the /2 and HS pulses to 2:1, the spin-echo phase is independent of offset frequency and varies as a function of B-1 strength. To eliminate undesired phase accumulations induced by unknown factors other than the B-1 strength, two spin-echo images are acquired using HS pulses applied with opposite frequency-sweep directions, and the resulting phase images are subtracted from each other. To demonstrate the performance of the proposed method, phantom and in vivo experiments were performed using a surface coil and a volume coil. ResultsThe B-1 maps obtained by using the proposed method were in accordance with the B-1 maps obtained using previous methods in both phantom and in vivo experiments. ConclusionThe proposed method is easy to implement without any sequence modification, is insensitive to B-0 inhomogeneity and chemical shift, and is robust in a reasonably wide range of B-1 field strength. Magn Reson Med 73:170-181, 2015. (c) 2014 Wiley Periodicals, Inc.
Keyword:
B-1 mapping
flip-angle mapping
RF field mapping
spin-echo imaging
hyperbolic secant pulse
frequency-modulation pulse
AI总结
对已上传原文的论文进行重点信息的提取,主要内容包括:简要概述、研究摘要、背景介绍、关键亮点、图文解析、展望与总结。
期刊
IF:
3
论文数:
1.2W
被引数:
3.1W
机构
引用论文
Exploring Students’ Experiences of Virtual Learning Environment for Art History Classroom探索学生体验:艺术史课堂中的虚拟学习环境

