Improved Liver R2* Mapping by Averaging Decay Curves.
Improved Liver R2* Mapping by Averaging Decay Curves.
复制标题
通过平均衰减曲线改进肝脏 R2 映射
DOI：
10.1038/s41598-017-05683-5
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发表时间：
2017-07-21
影响因子：
4.6
通讯作者：
He T
中科院分区：
文献类型：
--
作者：
Zhang X;Peng J;Wang C;Feng Y;Feng Q;Li X;Chen W;He T
肝脏R2* 标测通常因低信噪比（SNR）而降低，特别是在存在严重铁的情况下。本研究旨在通过在曲线拟合过程之前平均衰减曲线来改善低SNR下的肝脏R2* 映射。通过非局部均值（NLM）独立过滤回波图像证明了R2* 映射的质量得到了改善，但由于NLM滤波器的非线性性质，可能会引入新的误差，在此期间，平均权重可能会随着多个回波时间处的不同图像内容而变化。此外，当没有足够的相似块可用时，NLM的图像去噪效果可能会下降。为了克服这些缺点，我们提出了过滤衰减曲线而不是图像。在这种新的方案中，衰减曲线在一个局部窗口中平均，每个具有根据相邻曲线之一和目标曲线之间的距离测量的曲线相似性分配的权重。所提出的方法进行了测试模拟，幻影和患者数据。结果表明，所提出的方法可以提供更准确的R2* 映射相比，NLM算法，因此有可能提高诊断和治疗肝铁患者。
Liver R2* mapping is often degraded by the low signal-to-noise ratio (SNR) especially in the presence of severe iron. This study aims to improve liver R2* mapping at low SNRs by averaging decay curves before the process of curve-fitting. Independently filtering echo images by nonlocal means (NLM) demonstrated improved quality of R2* mapping, but may introduce new errors due to the nonlinear nature of the NLM filter, during which the averaging weights may vary with different image contents at multiple echo times. In addition, the image denoising effect of the NLM may decline when no sufficient similar patches are available. To overcome these drawbacks, we proposed to filter decay curves instead of images. In this novel scheme, decay curves were averaged in a local window, each with a weight assigned according to the curve-similarity measured by the distance between one of the neighboring curves and the targeted one. The proposed method was tested on simulated, phantom and patient data. The results demonstrate that the proposed method can provide more accurate R2* mapping compared with the NLM algorithm, and hence has the potential to improve diagnosis and therapy in patients with liver iron.
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DOI：
10.1186/1532-429x-16-40
发表时间：
2014-06-10
期刊：
Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
影响因子：
--
作者：
Garbowski MW;Carpenter JP;Smith G;Roughton M;Alam MH;He T;Pennell DJ;Porter JB
通讯作者：
Porter JB
影响因子：
3.3
作者：
Griswold, MA;Jakob, PM;Haase, A
通讯作者：
Haase, A
一种改进载铁肝脏 MRI R2* 松弛测量的新型半自动实质提取方法
影响因子：
4.4
作者：
Feng, Yanqiu;Feng, Meiyan;He, Taigang
通讯作者：
He, Taigang
影响因子：
3.3
作者：
He, Taigang;Gatehouse, Peter D.;Firmin, David N.
通讯作者：
Firmin, David N.
影响因子：
3.3
作者：
Hernando, Diego;Kramer, J. Harald;Reeder, Scott B.
通讯作者：
Reeder, Scott B.