Joseph Jesuchristopher, Warton Christopher, Jacobson Sandra W, Jacobson Joseph L, Molteno Chris D, Eicher Anton, Marais Patrick, Phillips Owen R, Narr Katherine L, Meintjes Ernesta M
MRC/UCT Medical Imaging Research Unit, Faculty of Health Sciences, University of Cape Town, South Africa; Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa.
Hum Brain Mapp. 2014 Feb;35(2):659-72. doi: 10.1002/hbm.22209. Epub 2012 Nov 5.
Surface deformation-based analysis was used to assess local shape variations in the hippocampi and caudate nuclei of children with fetal alcohol spectrum disorders. High-resolution structural magnetic resonance imaging images were acquired for 31 children (19 controls and 12 children diagnosed with fetal alcohol syndrome/partial FAS). Hippocampi and caudate nuclei were manually segmented, and surface meshes were reconstructed. An iterative closest point algorithm was used to register the template of one control subject to all other shapes in order to capture the true geometry of the shape with a fixed number of landmark points. A point distribution model was used to quantify the shape variations in terms of a change in co-ordinate positions. Using the localized Hotelling T(2) method, regions of significant shape variations between the control and exposed subjects were identified and mapped onto the mean shapes. Binary masks of hippocampi and caudate nuclei were generated from the segmented volumes of each brain. These were used to compute the volumes and for further statistical analysis. The Mann-Whitney test was performed to predict volume differences between the groups. Although the exposed and control subjects did not differ significantly in their volumes, the shape analysis showed the hippocampus to be more deformed at the head and tail regions in the alcohol-exposed children. Between-group differences in caudate nucleus morphology were dispersed across the tail and head regions. Correlation analysis showed associations between the degree of compression and the level of alcohol exposure. These findings demonstrate that shape analysis using three-dimensional surface measures is sensitive to fetal alcohol exposure and provides additional information than volumetric measures alone.
基于表面变形的分析方法被用于评估胎儿酒精谱系障碍儿童海马体和尾状核的局部形状变化。对31名儿童（19名对照儿童和12名被诊断为胎儿酒精综合征/部分胎儿酒精综合征的儿童）进行了高分辨率结构磁共振成像扫描。手动分割出海马体和尾状核，并重建表面网格。使用迭代最近点算法将一名对照受试者的模板与所有其他形状进行配准，以便用固定数量的地标点捕捉形状的真实几何形状。使用点分布模型根据坐标位置的变化来量化形状变化。采用局部Hotelling T(2)方法，识别出对照受试者和暴露组受试者之间形状有显著变化的区域，并将其映射到平均形状上。从每个大脑的分割体积中生成海马体和尾状核的二值掩码。这些掩码用于计算体积并进行进一步的统计分析。进行曼-惠特尼检验以预测两组之间的体积差异。虽然暴露组和对照组受试者的体积没有显著差异，但形状分析显示，酒精暴露儿童的海马体头部和尾部区域变形更明显。尾状核形态的组间差异分布在尾部和头部区域。相关性分析显示压缩程度与酒精暴露水平之间存在关联。这些发现表明，使用三维表面测量的形状分析对胎儿酒精暴露敏感，并且比单独的体积测量提供了更多信息。
