Deichmann R
Wellcome Department of Imaging Neuroscience, Institute of Neurology, 12 Queen Square, London WC1N 3BG, UK.
Neuroimage. 2006 Dec;33(4):1066-71. doi: 10.1016/j.neuroimage.2006.08.005. Epub 2006 Sep 18.
A sequence for the fast acquisition of T1 weighted structural brain images with whole brain coverage and isotropic resolution of 1mm is presented. It is based on MDEFT with a FLASH-EPI hybrid readout. Several techniques for artefact suppression are implemented, like echo time shifting, asymmetric k-space sampling, and navigator echo acquisition. It is shown experimentally that the hybrid MDEFT sequence with a total duration of 8min yields approximately the same signal-to-noise and contrast-to-noise ratios as a 12min standard MDEFT sequence based on a FLASH readout. Further experiments show that echo time shifting suppresses artefacts in the vicinity of the scalp and in areas suffering from field inhomogeneities and that the concept of asymmetric k-space sampling reduces the susceptibility to head movement.
本文介绍了一种用于快速采集全脑覆盖且各向同性分辨率为1mm的T1加权脑结构图像的序列。它基于具有FLASH-EPI混合读出的MDEFT。实施了多种伪影抑制技术，如回波时间偏移、非对称k空间采样和导航回波采集。实验表明，总时长为8分钟的混合MDEFT序列产生的信噪比和对比噪声比与基于FLASH读出的12分钟标准MDEFT序列大致相同。进一步的实验表明，回波时间偏移可抑制头皮附近和存在场不均匀性区域的伪影，并且非对称k空间采样的概念降低了对头部运动的敏感性。
