Comparison of diffusion tensor imaging measurements at 3.0 T versus 1.5 T with and without parallel Imaging
Comparison of diffusion tensor imaging measurements at 3.0 T versus 1.5 T with and without parallel Imaging
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DOI：
10.1016/j.nic.2006.02.006
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发表时间：
2006-05-01
影响因子：
2.3
通讯作者：
Field, AS
中科院分区：
文献类型：
--
作者：
Alexander, AL;Lee, JE;Field, AS
生物组织的扩散特性与磁场强度无关。然而，场强对扩散加权(DW)图像的信噪比(SNR)和伪影有影响，最终影响扩散张量成像(DTI)的定量和空间精度。本文综述了场强对DTI的影响。文中还讨论了并行成像的影响。进行了一项小型研究，比较了DTI测量作为场强(1.5T和3.0T)的函数和平行成像的结果。总体而言，从1.5T到3.0T，DW图像的SNR大约翻了一番，而使用并行成像时，SNR的降幅相对较小(15%到30%)。在3.0T时，信噪比越高，平均弥散系数和分数各向异性的估计值的方差越小。正如预期的那样，从1.5T到3.0T，回声平面图像的畸变量大约翻了一番，但使用并行成像时减少了50%。总而言之，与1.5T的研究相比，在3.0T下使用平行成像的DTI研究将提供显著改进的DTI测量。
The diffusion proper-ties of biological tissues are independent of magnetic field strength. Field strength, however, does affect the signal-to-noise ratio (SNR) and artifacts of diffusion-weighted (DW) images, which ultimately will influence the quantitative and spatial accuracy of diffusion tensor imaging (DTI). In this article, the effects of field strength on DTI are reviewed. The effects of parallel imaging also are discussed. A small study comparing DTI measurements both as a function of field strength (1.5 T and 3.0 T) and parallel imaging was performed. Overall, the SNR of the DW images roughly doubled going from 1.5 T to 3.0 T, and there was a relatively small decrease in SNR (15% to 30%) when parallel imaging was used. The increased SNR at 3.0 T resulted in smaller variances in the estimated mean diffusivities and fractional anisotropies. As expected, the amount of echo-planar image distortion roughly doubled going from 1.5 T to 3.0 T, but was reduced by 50% when using parallel imaging. In summary, DTI studies at 3.0 T using parallel imaging will provide significantly improved DTI measurements relative to studies at 1.5 T.