Fast T2 mapping with improved accuracy using undersampled spin-echo MRI and model-based reconstructions with a generating function.
Fast T2 mapping with improved accuracy using undersampled spin-echo MRI and model-based reconstructions with a generating function.
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DOI：
10.1109/tmi.2014.2333370
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发表时间：
2014-12
影响因子：
10.6
通讯作者：
Frahm J
中科院分区：
文献类型：
--
作者：
Sumpf TJ;Petrovic A;Uecker M;Knoll F;Frahm J
提出了一种基于模型的重建技术，利用欠采样笛卡尔自旋回波磁共振成像（MRI）数据加速T2映射的精度提高。该技术采用了先进的信号模型T2弛豫，占的贡献，从间接回波在一系列的多个自旋回波。非线性逆重建问题的迭代解直接从欠采样的原始数据估计自旋密度和T2图。针对模拟数据以及体模和3T下的人脑MRI验证了该算法。先进的模型的性能进行比较，以传统的基于像素的拟合回波时间图像从完全采样的数据。所提出的方法比单指数模型产生更准确的T2值，并允许至少6的回顾性欠采样因子。虽然对于非常长的T2弛豫时间观察到限制，但是可以通过梯度阻尼方法克服相应的重建问题。所使用的成本函数的分析梯度包括在附录中。源代码已提供给社区。
A model-based reconstruction technique for accelerated T2 mapping with improved accuracy is proposed using under-sampled Cartesian spin-echo magnetic resonance imaging (MRI) data. The technique employs an advanced signal model for T2 relaxation that accounts for contributions from indirect echoes in a train of multiple spin echoes. An iterative solution of the nonlinear inverse reconstruction problem directly estimates spin-density and T2 maps from undersampled raw data. The algorithm is validated for simulated data as well as phantom and human brain MRI at 3T. The performance of the advanced model is compared to conventional pixel-based fitting of echo-time images from fully sampled data. The proposed method yields more accurate T2 values than the mono-exponential model and allows for retrospective under-sampling factors of at least 6. Although limitations are observed for very long T2 relaxation times, respective reconstruction problems may be overcome by a gradient dampening approach. The analytical gradient of the utilized cost function is included as Appendix. The source code is made available to the community.