Time-efficient interleaved human 23Na and 1H data acquisition at 7 T
Time-efficient interleaved human 23Na and 1H data acquisition at 7 T
复制标题
DOI：
10.1002/nbm.3368
复制
发表时间：
2015-10-01
影响因子：
2.9
通讯作者：
Webb, Andrew G.
中科院分区：
文献类型：
--
作者：
de Bruin, Paul W.;Koken, Peter;Webb, Andrew G.
这项研究的目的是实施和评估一种灵活的、时间效率高的交叉成像方法，用于在临床相关的时间尺度内获取7T的人体膝关节的质子和钠图像。建立了一个灵活的软件框架，允许交叉扫描多个不同的、完全特定的吸收比(SAR)验证的扫描。该系统能够在灵活的时间点在这些不同的扫描之间切换。给出的实际例子由交错质子(Dixon成像和T-2*映射)和钠(分别映射钠含量和流体抑制组分)序列组成，其关键思想是在钠核松弛到热平衡时进行质子磁共振成像，反之亦然。在扫描仪操作的正常模式下顺序采集的这四个扫描和以交错方式采集的扫描之间进行比较。在交错模式下获得的图像与在顺序扫描中获得的图像非常相似，没有因稳态磁化强度的微小序列内变化而产生图像伪影。使用交错扫描将扫描时间减少了近两倍，从而允许在30分钟内完成这样的方案。在健康志愿者和一名患者身上进行的幻影实验和活体扫描证明了这种方法的基本可行性。这种方法用于交错多个质子和钠扫描，每个扫描具有不同的对比度，是设计新的实用的钠磁共振临床方案的有效方法。版权所有(C)2015 John Wiley&Sons，Ltd.
The aim of this study was to implement and evaluate a flexible and time-efficient interleaved imaging approach for the acquisition of proton and sodium images of the human knee at 7 T within a clinically relevant timescale. A flexible software framework was established which allowed the interleaving of multiple, different, fully specific absorption ratio (SAR)-validated scans. The system was able to switch between these different scans at flexible time points. The practical example presented consists of interleaved proton (Dixon imaging and T-2* mapping) and sodium (mapping the sodium content and fluid-suppressed component separately) sequences with the key idea to perform proton MRI whilst the sodium nuclei relax towards thermal equilibrium, and vice versa. Comparisons were made between these four scans being acquired sequentially in the normal mode of scanner operation and those acquired in an interleaved fashion. Images acquired in the interleaved mode were very similar to those acquired in sequential scans with no image artifacts produced by the slight intra-sequence variation in steady-state magnetization. A reduction in scanning time of almost a factor of two was established using the interleaved scans, allowing such a protocol to be completed within 30 min. Phantom experiments and in vivo scans performed in healthy volunteers and in one patient proved the basic feasibility of this approach. This approach for the interleaving of multiple proton and sodium scans, each with different contrasts, is an efficient method for the design of new practical clinical protocols for sodium MRI. Copyright (C) 2015 John Wiley & Sons, Ltd.