Improving Chemical Shift Encoded Water-Fat Separation Using Object-Based Information of the Magnetic Field Inhomogeneity
Improving Chemical Shift Encoded Water-Fat Separation Using Object-Based Information of the Magnetic Field Inhomogeneity
复制标题
DOI：
10.1002/mrm.25163
复制
发表时间：
2015-02-01
影响因子：
3.3
通讯作者：
Reeder, Scott B.
中科院分区：
文献类型：
--
作者：
Sharma, Samir D.;Artz, Nathan S.;Reeder, Scott B.
目的这项工作的目的是通过结合基于对象的 B0 场不均匀性信息来提高现有化学位移编码水脂分离方法的鲁棒性。理论水脂分离的主要挑战是估计由 B0 场不均匀性引起的相移，B0 场不均匀性由背景场和磁化率诱导场组成。如果磁化率分布已知或可以近似，则可以估计磁化率感应场。在这项工作中，使用水、脂肪和空气的已知磁化率值从源图像近似磁化率分布。然后在水脂分离之前从源图像中解调场估计。方法在容易发生水脂交换的解剖区域中获取化学位移编码的源图像。使用 ISMRM Fat-Water Toolbox 中的算法处理图像，包含或不包含基于对象的现场地图信息。对估计值进行比较，以检验使用基于对象的场图信息的好处。结果显示了使用基于对象的 B0 场图信息避免水脂肪交换的多种情况。结论基于对象的 B0 场信息可以提高现有化学位移编码水脂肪分离方法的鲁棒性。 Magn Reson Med 73:597-604, 2015。(c) 2014 Wiley periodicals, Inc.
PurposeThe purpose of this work was to improve the robustness of existing chemical shift encoded water-fat separation methods by incorporating object-based information of the B0 field inhomogeneity.TheoryThe primary challenge in water-fat separation is the estimation of phase shifts that arise from B0 field inhomogeneity, which is composed of the background field and susceptibility-induced field. The susceptibility-induced field can be estimated if the susceptibility distribution is known or can be approximated. In this work, the susceptibility distribution is approximated from the source images using the known susceptibility values of water, fat, and air. The field estimate is then demodulated from the source images before water-fat separation.MethodsChemical shift encoded source images were acquired in anatomical regions that are prone to water-fat swaps. The images were processed using algorithms from the ISMRM Fat-Water Toolbox, with and without the object-based field map information. The estimates were compared to examine the benefit of using the object-based field map information.ResultsMultiple cases are shown in which water-fat swaps were avoided by using the object-based information of the B0 field map.ConclusionObject-based information of the B0 field may improve the robustness of existing chemical shift encoded water-fat separation methods. Magn Reson Med 73:597-604, 2015. (c) 2014 Wiley Periodicals, Inc.