Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL USA.
Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois USA.
Neuroimage. 2022 Oct 15;260:119417. doi: 10.1016/j.neuroimage.2022.119417. Epub 2022 Jul 3.
High-quality T-weighted (Tw) and diffusion tensor imaging (DTI) brain templates that are representative of the individuals under study enhance the accuracy of template-based neuroimaging investigations, and when they are also located in a common space they facilitate optimal integration of information on brain morphometry and diffusion characteristics. However, such multimodal templates have not been constructed for the brain of older adults. The purpose of this work was threefold: (A) to introduce an iterative method for construction of multimodal Tw and DTI templates that aims at maximizing the quality of each template separately as well as the spatial matching between templates, (B) to use this method to develop Tw and DTI templates of the older adult brain in a common space, and (C) to evaluate the performance of the method across iterations and compare it to the performance of state-of-the-art approaches based on multichannel registration. It was demonstrated that more iterations of the proposed method enhanced the characteristics and spatial matching of the resulting Tw and DTI templates. The templates of the older adult brain generated by the final iteration of the proposed method provided better delineation of brain structures, higher discriminability between tissues, and higher image sharpness near the cortex compared to templates generated with approaches employing multichannel registration. In addition, the spatial matching between the Tw and DTI templates constructed by the proposed method approximated the template alignment achieved with methods employing multichannel registration. Finally, when using the templates generated by the proposed method as references for spatial normalization of older adult Tw and DTI data, both the intra-modality inter-subject normalization precision and the inter-modality spatial matching were higher in most metrics than those achieved with templates constructed with other methods. Overall, the present work brought new insights into multimodal template construction, generated much-needed high quality Tw and DTI templates of the older adult brain in a common space, and conducted a thorough, quantitative evaluation of available multimodal template construction methods.
高质量的 T 加权（Tw）和弥散张量成像（DTI）脑模板，代表了研究对象的个体，可提高基于模板的神经影像学研究的准确性，并且当它们位于共同空间中时，还可促进脑形态和弥散特征信息的最佳整合。然而，目前尚未为老年人的大脑构建这种多模态模板。本研究的目的有三：（A）介绍一种迭代方法，用于构建旨在分别最大化每个模板的质量以及模板之间的空间匹配的多模态 Tw 和 DTI 模板；（B）使用该方法在共同空间中构建老年人的大脑 Tw 和 DTI 模板；（C）评估该方法在不同迭代中的性能，并将其与基于多通道配准的最新方法的性能进行比较。结果表明，该方法的更多迭代增强了生成的 Tw 和 DTI 模板的特征和空间匹配。与使用多通道配准的方法生成的模板相比，该方法的最后迭代生成的老年人大脑模板提供了更好的脑结构描绘、组织之间更高的可区分性以及靠近皮质的更高图像清晰度。此外，所提出的方法构建的 Tw 和 DTI 模板之间的空间匹配接近使用多通道配准的方法实现的模板对齐。最后，当使用所提出的方法生成的模板作为老年人 Tw 和 DTI 数据的空间归一化参考时，大多数指标下的模态内个体间归一化精度和模态间空间匹配都高于使用其他方法构建的模板。总的来说，本研究为多模态模板构建提供了新的见解，生成了急需的、具有共同空间的老年人大脑高质量的 Tw 和 DTI 模板，并对现有的多模态模板构建方法进行了全面、定量的评估。
