Automated design of pulse sequences for magnetic resonance fingerprinting using physics-inspired optimization
Automated design of pulse sequences for magnetic resonance fingerprinting using physics-inspired optimization
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DOI：
10.1073/pnas.2020516118
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发表时间：
2021-10-05
影响因子：
11.1
通讯作者：
Ma, Dan
中科院分区：
文献类型：
--
作者：
Jordan, Stephen P.;Hu, Siyuan;Ma, Dan
磁共振指纹（MRF）是一种使用常规MRI硬件从任意脉冲序列中提取定量组织特性（如T1和T2弛豫率）的方法。MRF脉冲序列具有数千个可调参数，可以选择这些参数以最大化精度并最小化扫描时间。在这里，我们执行从头自动设计的MRF脉冲序列，通过应用物理启发的优化算法。我们的实验数据表明，系统误差占主导地位的随机误差在磁共振成像扫描在临床相关的条件下，高采样不足。因此，在以前的优化工作，集中在统计误差模型，我们使用的成本函数的基础上明确的第一性原理模拟的系统误差所产生的傅立叶欠采样和相位变化。由此产生的脉冲序列显示的功能与以前使用的MRF脉冲序列有质的不同，并实现四倍短的扫描时间比以前的人类设计的序列在T1和T2的同等精度。此外，优化算法还发现了MRF脉冲序列的存在，该脉冲序列对相位变化引起的阴影伪影具有固有的鲁棒性。
Magnetic resonance fingerprinting (MRF) is a method to extract quantitative tissue properties such as T1 and T2 relaxation rates from arbitrary pulse sequences using conventional MRI hardware. MRF pulse sequences have thousands of tunable parameters, which can be chosen to maximize precision and minimize scan time. Here, we perform de novo automated design of MRF pulse sequences by applying physics-inspired optimization heuristics. Our experimental data suggest that systematic errors dominate over random errors in MRF scans under clinically relevant conditions of high undersampling. Thus, in contrast to prior optimization efforts, which focused on statistical error models, we use a cost function based on explicit first-principles simulation of systematic errors arising from Fourier undersampling and phase variation. The resulting pulse sequences display features qualitatively different from previously used MRF pulse sequences and achieve fourfold shorter scan time than prior human-designed sequences of equivalent precision in T1 and T2. Furthermore, the optimization algorithm has discovered the existence of MRF pulse sequences with intrinsic robustness against shading artifacts due to phase variation.