Arfanakis Konstantinos, Gui Minzhi, Lazar Mariana
Department of Biomedical Engineering, Illinois Institute of Technology, 10 West 32nd Street, E1-116, Chicago, IL 60616, USA.
Ann N Y Acad Sci. 2005 Dec;1064:78-87. doi: 10.1196/annals.1340.014.
White matter fiber-tractography by means of diffusion tensor imaging (DTI) is a noninvasive technique that provides estimates of the structural connectivity of the brain. However, conventional fiber-tracking methods using DTI are based on echo-planar image acquisitions (EPI), which suffer from image distortions and artifacts due to magnetic susceptibility variations and eddy currents. Thus, a large percentage of white matter fiber bundles that are mapped using EPI-based DTI data are distorted, and/or terminated early, while others are completely undetected. This severely limits the potential of fiber-tracking techniques. In contrast, Turboprop imaging is a multiple-shot gradient and spin-echo (GRASE) technique that provides images with significantly fewer susceptibility and eddy current-related artifacts than EPI. The purpose of this work was to evaluate the performance of fiber-tractography techniques when using data obtained with Turboprop-DTI. All fiber pathways that were mapped were found to be in agreement with the anatomy. There were no visible distortions in any of the traced fiber bundles, even when these were located in the vicinity of significant magnetic field inhomogeneities. Additionally, the Turboprop-DTI data used in this research were acquired in less than 19 min of scan time. Thus, Turboprop appears to be a promising DTI data acquisition technique for tracing white matter fibers.
通过扩散张量成像(DTI)进行的白质纤维束成像,是一种能提供大脑结构连通性估计值的非侵入性技术。然而,使用DTI的传统纤维追踪方法基于回波平面成像采集(EPI),由于磁化率变化和涡流,这种采集方式会产生图像失真和伪影。因此,使用基于EPI的DTI数据绘制的白质纤维束中,很大一部分会出现扭曲和/或提前终止,而其他一些纤维束则完全无法检测到。这严重限制了纤维追踪技术的潜力。相比之下,涡轮螺旋桨成像(Turboprop)是一种多次激发梯度和自旋回波(GRASE)技术,与EPI相比,它所提供图像的磁化率和涡流相关伪影要少得多。这项工作的目的是评估使用Turboprop-DTI获得的数据时纤维束成像技术的性能。所有绘制的纤维路径都与解剖结构相符。即使是位于显著磁场不均匀区域附近的纤维束,在任何追踪到的纤维束中都没有可见的扭曲。此外,本研究中使用的Turboprop-DTI数据在不到19分钟的扫描时间内就采集完成。因此,Turboprop似乎是一种用于追踪白质纤维的很有前景的DTI数据采集技术。