Cortical thickness determination of the human brain using high resolution 3 T and 7 T MRI data
Cortical thickness determination of the human brain using high resolution 3 T and 7 T MRI data
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DOI：
10.1016/j.neuroimage.2012.12.016
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发表时间：
2013-04-15
期刊：
影响因子：
5.7
通讯作者：
Speck, Oliver
中科院分区：
文献类型：
--
作者：
Luesebrink, Falk;Wollrab, Astrid;Speck, Oliver
目的：对人类大脑皮层的分析和基于MRI数据的厚度测量可以提供对正常大脑发育和神经退行性疾病的洞察。皮质厚度测量的准确和可再现的结果对于灵敏检测是期望的。本研究比较了超高分辨率数据采集在7 T与3 T的数据，用于确定人脑皮层厚度。方法：对5名受试者分别在3 T（1 mm各向同性分辨率）和7 T（1 mm和0.5mm各向同性分辨率）下进行3DMP-MRI和3D梯度回波扫描。由于B1场引起的7 T数据的不均匀信号和对比度通过用GE划分MP-T来校正。利用基于体素的方法的ARCTIC和利用基于表面的方法的FreeSurfer已被用于计算高分辨率3 T和7 T数据以及超高分辨率7 T数据的皮质厚度。FreeSurfer的设计不适用于处理空间分辨率超过1 mm的数据，因此进行了修改以避免这一限制。此外，SPM和FSL已被用来生成分割，进一步处理与ARCTIC，以确定皮质thickness.Results和结论：在相同的分辨率，皮质厚度的测定产生一致的结果之间的3 T和7 T确认的鲁棒性的收购和处理对潜在的场强相关的影响。然而，与较低分辨率数据相比，超高分辨率7 T数据导致皮质厚度估计值显著降低。厚度的减少量约为六分之一到三分之一，这取决于所使用的处理算法和软件。这表明由于部分体积效应导致的灰质分割中的偏差，并且表明使用基于体素或基于表面的方法的大多数当前MR研究高估了真实皮质厚度，并且可以使用7 T的高分辨率成像更准确地确定。(C)2012 Elsevier Inc. All rights reserved.
Purpose: The analysis of the human cerebral cortex and the measurement of its thickness based on MRI data can provide insight into normal brain development and neurodegenerative disorders. Accurate and reproducible results of the cortical thickness measurement are desired for sensitive detection. This study compares ultra-high resolution data acquired at 7 T with 3 T data for determination of the cortical thickness of the human brain. The impact of field strength, resolution, and processing method is evaluated systematically.Methods: Five subjects were scanned at 3 T (1 mm isotropic resolution) and 7 T (1 mm and 0.5 mm isotropic resolution) with 3D MP-RAGE and 3D gradient echo methods. The inhomogeneous signal and contrast of the 7 T data due to the B1 field was corrected by division of the MP-RAGE with the GE. ARCTIC, utilizing a voxel-based approach, and FreeSurfer, utilizing a surface-based approach, have been used to compute the cortical thickness of the high resolution 3 T and 7 T data and of the ultra-high resolution 7 T data. FreeSurfer is not designed to process data with a spatial resolution other than 1 mm and was modified to avoid this limitation. Additionally SPM and FSL have been used to generate segmentations which were further processed with ARCTIC to determine the cortical thickness.Results and Conclusion: At identical resolution, the cortical thickness determination yielded consistent results between 3 T and 7 T confirming the robustness of the acquisition and processing against potential field strength related effects. However, the ultra-high resolution 7 T data resulted in significantly reduced values for the cortical thickness estimation compared to the lower resolution data. The reduction in thickness amounts approximately one sixth to one third, depending on the processing algorithm and software used. This suggests a bias in the gray matter segmentation due to partial volume effects and indicates that true cortical thickness is overestimated by most current MR studies using both a voxel-based or surface-based method and can be more accurately determined with high resolution imaging at 7 T. (C) 2012 Elsevier Inc. All rights reserved.