Signal Compensation and Compressed Sensing for Magnetization-Prepared MR Angiography
Signal Compensation and Compressed Sensing for Magnetization-Prepared MR Angiography
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DOI：
10.1109/tmi.2011.2116123
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发表时间：
2011-05-01
影响因子：
10.6
通讯作者：
Nishimura, Dwight G.
中科院分区：
文献类型：
--
作者：
Cukur, Tolga;Lustig, Michael;Nishimura, Dwight G.
磁化准备采集提供了磁共振成像的图像对比度和扫描效率之间的权衡。由于准备的信号逐渐衰减，因此可以通过频繁重复准备来提高对比度，这反过来又显著增加了扫描时间。一种常见的解决方案是在每次制备之后从低空间频率样本到高空间频率样本进行数据收集。不幸的是，这导致空间分辨率的损失，从而导致图像模糊。在这项工作中，提出了一种新的技术，首先纠正高频数据中的信号衰减，以减轻分辨率损失，提高图像对比度，而不会降低扫描效率。所提出的技术，然后采用基于稀疏的非线性重建，以进一步提高图像质量。除了减少放大的高频噪声之外，该重建还在欠采样压缩感知采集的情况下外推缺失的k空间样本。该技术成功地证明了下肢的非对比度增强血流无关血管造影，信号补偿和非线性重建的应用程序，大大受益。
Magnetization-prepared acquisitions offer a trade-off between image contrast and scan efficiency for magnetic resonance imaging. Because the prepared signals gradually decay, the contrast can be improved by frequently repeating the preparation, which in turn significantly increases the scan time. A common solution is to perform the data collection progressing from low-to high-spatial-frequency samples following each preparation. Unfortunately, this leads to loss of spatial resolution, and thereby image blurring. In this work, a new technique is proposed that first corrects the signal decay in high-frequency data to mitigate the resolution loss and improve the image contrast without reducing the scan efficiency. The proposed technique then employs a sparsity-based nonlinear reconstruction to further improve the image quality. In addition to reducing the amplified high-frequency noise, this reconstruction extrapolates missing k-space samples in the case of undersampled compressed-sensing acquisitions. The technique is successfully demonstrated for noncontrast-enhanced flow-independent angiography of the lower extremities, an application that substantially benefits from both the signal compensation and the nonlinear reconstruction.