Brain Center Rudolf Magnus, Department of Psychiatry, Brain Division, University Medical Center Utrecht, Utrecht University, HPNR A01.126, Heidelberglaan 100, 3584, CG, Utrecht, The Netherlands.
Radiology Department, Imaging Division, University Medical Center Utrecht, Heidelberglaan 100, 3584, CG, Utrecht, The Netherlands.
Neuroinformatics. 2018 Apr;16(2):181-196. doi: 10.1007/s12021-018-9356-2.
Studies into cortical thickness in psychiatric diseases based on T1-weighted MRI frequently report on aberrations in the cerebral cortex. Due to limitations in image resolution for studies conducted at conventional MRI field strengths (e.g. 3 Tesla (T)) this information cannot be used to establish which of the cortical layers may be implicated. Here we propose a new analysis method that computes one high-resolution average cortical profile per brain region extracting myeloarchitectural information from T1-weighted MRI scans that are routinely acquired at a conventional field strength. To assess this new method, we acquired standard T1-weighted scans at 3 T and compared them with state-of-the-art ultra-high resolution T1-weighted scans optimised for intracortical myelin contrast acquired at 7 T. Average cortical profiles were computed for seven different brain regions. Besides a qualitative comparison between the 3 T scans, 7 T scans, and results from literature, we tested if the results from dynamic time warping-based clustering are similar for the cortical profiles computed from 7 T and 3 T data. In addition, we quantitatively compared cortical profiles computed for V1, V2 and V7 for both 7 T and 3 T data using a priori information on their relative myelin concentration. Although qualitative comparisons show that at an individual level average profiles computed for 7 T have more pronounced features than 3 T profiles the results from the quantitative analyses suggest that average cortical profiles computed from T1-weighted scans acquired at 3 T indeed contain myeloarchitectural information similar to profiles computed from the scans acquired at 7 T. The proposed method therefore provides a step forward to study cortical myeloarchitecture in vivo at conventional magnetic field strength both in health and disease.
基于 T1 加权 MRI 的精神疾病皮质厚度研究经常报告大脑皮层的异常。由于常规 MRI 场强（例如 3 特斯拉（T））下进行的研究的图像分辨率有限，因此无法使用这些信息来确定哪些皮质层可能受到影响。在这里，我们提出了一种新的分析方法，该方法可以为每个大脑区域计算一个高分辨率的平均皮质轮廓，从常规场强下常规获取的 T1 加权 MRI 扫描中提取髓鞘结构信息。为了评估这种新方法，我们在 3T 处获取了标准 T1 加权扫描，并将其与针对 7T 下皮质内髓鞘对比度优化的最先进超高分辨率 T1 加权扫描进行了比较。为七个不同的大脑区域计算了平均皮质轮廓。除了对 3T 扫描、7T 扫描和文献结果进行定性比较之外，我们还测试了基于动态时间 warping 的聚类的结果是否对于从 7T 和 3T 数据计算出的皮质轮廓相似。此外，我们使用有关其相对髓鞘浓度的先验信息，对来自 7T 和 3T 数据的 V1、V2 和 V7 的皮质轮廓进行了定量比较。尽管定性比较表明，在个体水平上，7T 计算出的平均轮廓比 3T 轮廓具有更明显的特征，但定量分析的结果表明，从 3T 获取的 T1 加权扫描计算出的平均皮质轮廓确实包含与从 7T 获取的扫描计算出的轮廓相似的髓鞘结构信息。因此，该方法为在常规磁场强度下研究健康和疾病中的皮质髓鞘结构提供了一个新的步骤。
