High resolution MRI of the brain at 4.7 Tesla using fast spin echo imaging
High resolution MRI of the brain at 4.7 Tesla using fast spin echo imaging
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DOI：
10.1259/bjr/69317841
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发表时间：
2003-09-01
影响因子：
2.6
通讯作者：
Ordidge, RJ
中科院分区：
文献类型：
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作者：
De Vita, E;Thomas, DL;Ordidge, RJ
近年来，高场磁共振扫描仪（3t及以上）由于具有更高的信噪比等潜在优势而变得越来越普遍。然而，迄今为止，在合理的采集时间内覆盖整个大脑的高分辨率图像的例子很少，而且没有一个使用快速自旋回波（FSE），这是一种通常用于采集1.5 t的T-2加权图像的序列，这主要是由于与均匀信号产生相关的技术挑战增加以及当前高场安全指南日益严格的约束。我们使用4.7 T环境优化的FSE序列对10名志愿者进行了调查。该序列可以分别在5分钟40秒和11分钟20秒内获取17层和34层数据集，面内分辨率约为500 μ m × 500 μ m，层厚为2mm。图像出现T-2加权，尽管对比度是由于选择的回波时间，磁化转移，直接射频饱和和扩散以及组织的T和T-2松弛时间的综合影响。结果是解剖结构的详细可视化，显示了4.7 T MRI在临床应用中的巨大潜力。本文表明，通过对序列参数的精心优化，FSE成像可以在高视场下在规定的功率沉积范围内生成高空间分辨率和均匀对比度的全脑图像。
Over recent years, high field MR scanners (3 T and above) have become increasingly widespread due to potential advantages such as higher signal-to-noise ratio. However, few examples of high resolution images covering the whole brain in reasonable acquisition times have been published to date and none have used fast spin echo (FSE), a sequence commonly employed for the acquisition of T-2 weighted images at 1.5 T. This is mostly due to the increased technical challenges associated with uniform signal generation and the increasingly restrictive constraints of current safety guidelines at high field. We investigated 10 volunteers using an FSE sequence optimized to the 4.7 T environment. This sequence allows the acquisition of 17- and 34-slice data sets with an in-plane resolution of approximately 500 mum x 500 mum and a slice thickness of 2 mm, in 5 min 40 s and 11 min 20 s, respectively. The images appear T-2 weighted, although the contrast is due to the combined effects of chosen echo time, magnetization transfer, direct radio frequency saturation and diffusion as well as the T, and T-2 relaxation times of the tissue. The result is an excellent detailed visualization of anatomical structures, demonstrating the great potential of 4.7 T MRI for clinical applications. This paper shows that, with careful optimization of sequence parameters, FSE imaging can be used at high field to generate images with high spatial resolution and uniform contrast across the whole brain within the prescribed power deposition limits.