论文标题
具有压缩感测和距离度量学习的磁共振指纹识别
Magnetic Resonance Fingerprinting with compressed sensing and distance metric learning
论文作者
论文摘要
磁共振指纹（MRF）是一种新型技术，它同时估算了多个与组织相关的参数，例如纵向松弛时间T1，横向松弛时间T2，离子频率B0和质子密度，从二十次仅数十个中的扫描对象。但是，MRF方法遭受了混乱的伪像，因为它明显地示例了K空间数据。在这项工作中，我们提出了一个基于MRF方法同时估算多个组织相关参数的压缩传感（CS）框架。它比低采样比更健壮，因此在估计对象的所有体素的MR参数方面更有效。此外，MRF方法需要从具有L2距离的MR-Signal-Evolution词典中识别查询指纹的最接近原子。但是，我们观察到L2距离并不总是适当的指标，可以测量MR指纹之间的相似性。从不足采样的训练数据中自适应地学习距离度量，可以显着提高查询指纹的匹配精度。广泛的模拟案例的数值结果表明，就参数估计的准确性而言，我们的方法基本上优于现行方法。
Magnetic Resonance Fingerprinting (MRF) is a novel technique that simultaneously estimates multiple tissue-related parameters, such as the longitudinal relaxation time T1, the transverse relaxation time T2, off resonance frequency B0 and proton density, from a scanned object in just tens of seconds. However, the MRF method suffers from aliasing artifacts because it significantly undersamples the k-space data. In this work, we propose a compressed sensing (CS) framework for simultaneously estimating multiple tissue-related parameters based on the MRF method. It is more robust to low sampling ratio and is therefore more efficient in estimating MR parameters for all voxels of an object. Furthermore, the MRF method requires identifying the nearest atoms of the query fingerprints from the MR-signal-evolution dictionary with the L2 distance. However, we observed that the L2 distance is not always a proper metric to measure the similarities between MR Fingerprints. Adaptively learning a distance metric from the undersampled training data can significantly improve the matching accuracy of the query fingerprints. Numerical results on extensive simulated cases show that our method substantially outperforms stateof-the-art methods in terms of accuracy of parameter estimation.
