Vardhan Avantika, Prastawa Marcel, Gouttard Sylvain, Piven Joseph, Gerig Guido
Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112.
Proc IEEE Int Symp Biomed Imaging. 2012:1156-1159. doi: 10.1109/isbi.2012.6235765.
Quantitative analysis of early brain development through imaging is critical for identifying pathological development, which may in turn affect treatment procedures. We propose a framework for analyzing spatiotemporal patterns of brain maturation by quantifying intensity changes in longitudinal MR images. We use a measure of divergence between a pair of intensity distributions to study the changes that occur within specific regions, as well as between a pair of anatomical regions, over time. The change within a specific region is measured as the contrast between white matter and gray matter tissue belonging to that region. The change between a pair of regions is measured as the divergence between regional image appearances, summed over all tissue classes. We use kernel regression to integrate the temporal information across different subjects in a consistent manner. We applied our method on multimodal MRI data with T1-weighted (T1W) and T2-weighted (T2W) scans of each subject at the approximate ages of 6 months, 12 months, and 24 months. The results demonstrate that brain maturation begins at posterior regions and that frontal regions develop later, which matches previously published histological, qualitative and morphometric studies. Our multimodal analysis also confirms that T1W and T2W modalities capture different properties of the maturation process, a phenomena referred to as T2 time lag compared to T1. The proposed method has potential for analyzing regional growth patterns across different populations and for isolating specific critical maturation phases in different MR modalities.
通过成像对早期大脑发育进行定量分析对于识别病理性发育至关重要，而病理性发育反过来可能会影响治疗程序。我们提出了一个框架，通过量化纵向磁共振成像（MR）图像中的强度变化来分析大脑成熟的时空模式。我们使用一对强度分布之间的散度度量来研究特定区域内以及一对解剖区域之间随时间发生的变化。特定区域内的变化通过属于该区域的白质和灰质组织之间的对比度来衡量。一对区域之间的变化通过区域图像外观之间的散度来衡量，对所有组织类别求和。我们使用核回归以一致的方式整合不同受试者的时间信息。我们将我们的方法应用于多模态MRI数据，每个受试者在大约6个月、12个月和24个月时进行了T1加权（T1W）和T2加权（T2W）扫描。结果表明，大脑成熟始于后部区域，额叶区域发育较晚，这与先前发表的组织学、定性和形态计量学研究结果相符。我们的多模态分析还证实，T1W和T2W模态捕捉到了成熟过程的不同特性，这种现象与T1相比被称为T2时间滞后。所提出的方法有潜力分析不同人群的区域生长模式，并在不同的MR模态中分离出特定的关键成熟阶段。
