论文标题
基于深度学习的参数映射,用于关节放松和扩散张量MR指纹图
Deep learning-based parameter mapping for joint relaxation and diffusion tensor MR Fingerprinting
论文作者
论文摘要
磁共振指纹(MRF)可以同时定量生物组织的多种性质。它依赖于伪随机的采集以及获得的信号演变与预定词典的匹配。但是,字典不可扩展到更高的参数空间,将MRF限制在仅少量参数(质子密度,T1和T2)的同时映射。受扩散加权SSFP成像的启发,我们呈现了新型MRF序列的概念概念,并沿所有三个轴嵌入了嵌入式扩散 - 编码梯度,以有效地编码定向扩散以及T1和T2弛豫。我们利用卷积神经网络(CNN)从这个单一的,高度不足的采集中重建多个定量图。我们通过学习时空MRF数据与T1,T2和扩散张量参数之间的隐式物理关系来绕过昂贵的字典匹配。预测的参数图和派生的标量扩散指标与最新的参考协议非常吻合。从估计的主要扩散方向看,捕获了定向扩散信息。除此之外,联合采集和重建框架还证明能够在多发性硬化病变中保留组织异常。
Magnetic Resonance Fingerprinting (MRF) enables the simultaneous quantification of multiple properties of biological tissues. It relies on a pseudo-random acquisition and the matching of acquired signal evolutions to a precomputed dictionary. However, the dictionary is not scalable to higher-parametric spaces, limiting MRF to the simultaneous mapping of only a small number of parameters (proton density, T1 and T2 in general). Inspired by diffusion-weighted SSFP imaging, we present a proof-of-concept of a novel MRF sequence with embedded diffusion-encoding gradients along all three axes to efficiently encode orientational diffusion and T1 and T2 relaxation. We take advantage of a convolutional neural network (CNN) to reconstruct multiple quantitative maps from this single, highly undersampled acquisition. We bypass expensive dictionary matching by learning the implicit physical relationships between the spatiotemporal MRF data and the T1, T2 and diffusion tensor parameters. The predicted parameter maps and the derived scalar diffusion metrics agree well with state-of-the-art reference protocols. Orientational diffusion information is captured as seen from the estimated primary diffusion directions. In addition to this, the joint acquisition and reconstruction framework proves capable of preserving tissue abnormalities in multiple sclerosis lesions.