Field map estimation with a region growing scheme for iterative 3-point water-fat decomposition
Field map estimation with a region growing scheme for iterative 3-point water-fat decomposition
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DOI：
10.1002/mrm.20654
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发表时间：
2005-10-01
影响因子：
3.3
通讯作者：
Pelc, NJ
中科院分区：
文献类型：
--
作者：
Yu, HZ;Reeder, SB;Pelc, NJ
许多临床应用都需要稳健的脂肪抑制技术。与脂肪饱和法相比，多回波水脂分离法对B-0场的不均匀性相对不敏感。对这种场不均匀性或场图的估计是一个基本和重要的步骤，众所周知，这是具有模糊性的。对于最近提出的一种迭代水脂分解方法，仍然存在歧义，但本质上更加复杂。通过解析表达式和模拟对它们进行了研究。为了避免收敛到不正确的场映射解，需要更接近真实场映射的初始猜测。这可以使用区域生长过程来实现，该过程将相邻像素之间的估计关联起来。通过使用低分辨率重建来指导区域生长的起始像素的选择，实现了稳定性的进一步改善。实现结果表明，该方法显著提高了算法的抗场不均匀能力。
Robust fat suppression techniques are required for many clinical applications. Multi-echo water-fat separation methods are relatively insensitive to B-0 field inhomogeneity compared to the fat saturation method. Estimation of this field inhomogeneity, or field map, is an essential and important step, which is well known to have ambiguity. For an iterative water-fat decomposition method recently proposed, ambiguities still exist, but are more complex in nature. They were studied by analytical expressions and simulations. To avoid convergence to incorrect field map solutions, an initial guess closer to the true field map is necessary. This can be achieved using a region growing process, which correlates the estimation among neighboring pixels. Further improvement in stability is achieved using a low-resolution reconstruction to guide the selection of the starting pixels for the region growing. The proposed method was implemented and shown to significantly improve the algorithm's immunity to field inhomogeneity.