Fast quantitative parameter maps without fitting: Integration yields accurate mono-exponential signal decay rates.
Fast quantitative parameter maps without fitting: Integration yields accurate mono-exponential signal decay rates.
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DOI：
10.1002/mrm.26964
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发表时间：
2018-06
影响因子：
3.3
通讯作者：
Hillenbrand CM
中科院分区：
文献类型：
--
作者：
Song R;Loeffler RB;Holtrop JL;McCarville MB;Hankins JS;Hillenbrand CM
开发一种计算快速和准确的单指数信号建模算法，并在用于铁过载评估的R2*映射的背景下验证新技术。介绍了一种基于单指数信号衰减曲线的积分直接从一系列图像中计算R2*值的算法。该算法速度很快，因为避免了拟合，只进行了算术计算，而不需要迭代。与依赖迭代曲线拟合的传统对数线性(LL)法、基于最小二乘法(NLM)和平方非线性Levenberg-MarQuardt(SQNLM)法进行了比较，确定了该方法的精度和精度。在仿真中，在R2*值从50 S−1到1200 S−1的范围内，基于信号积分的方法始终具有与LL、NLm和SQNLm算法相同或更高的精度。在体模和活体(12名参与者)中，该方法在很大范围的R2*值和SNR范围内都是稳健的。计算时间分别比LL、NLM和SQNLM方法快100倍、1460倍和930倍。快速信号积分方法可精确计算R2*图。它有可能取代传统的单指数拟合方法，用于定量磁共振成像，如R2*参数映射。
To develop a computationally fast and accurate algorithm for mono-exponential signal modelling and validate the new technique in the context of R2* mapping for iron overload assessment. An algorithm is introduced that directly calculates R2* values from a series of images based on integration of the mono-exponential signal decay curve. The algorithm is fast, because fitting is avoided and only arithmetic computations without iterations are applied. Precision and accuracy of the method is determined in comparison to the conventional log-linear (LL), least-squares–based Levenberg–Marquardt (NLM), and squared nonlinear Levenberg–Marquardt (SQNLM) methods, which rely on iterative curve fitting. In simulations, the signal integration based method consistently had the same or better accuracy than the LL, NLM, and SQNLM algorithms for R2* values ranging from 50 s−1 to 1200 s−1. In phantoms and in vivo (12 participants), this method was robust over a wide range of R2* values and SNRs. Computation times were about 100, 1460, and 930 times faster than those of the LL, NLM, and SQNLM methods, respectively. The fast signal integration method accurately calculates R2* maps. It has the potential to replace conventional, mono-exponential fitting methods for quantitative MRI such as R2* parameter mapping.
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影响因子：
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