University of Minnesota, Twin Cities, Minnesota 55454, USA.
Alcohol Clin Exp Res. 2009 Oct;33(10):1825-35. doi: 10.1111/j.1530-0277.2009.01021.x. Epub 2009 Jul 23.
Several studies have now shown corpus callosum abnormalities using diffusion tensor imaging (DTI) in children with fetal alcohol spectrum disorders (FASD) in comparison with nonexposed controls. The data suggest that posterior regions of the callosum may be disproportionately affected. The current study builds on previous efforts, including our own work, and moves beyond midline corpus callosum to probe major inter-hemispheric white matter pathways with an improved DTI tractographic method. This study also expands on our prior work by evaluating a larger sample and by incorporating children with a broader range of clinical effects including full-criteria fetal alcohol syndrome (FAS).
Participants included 33 children with FASD (8 FAS, 23 partial FAS, 2 static encephalopathy) and 19 nonexposed controls between the ages of 10 and 17 years. Participants underwent DTI scans and intelligence testing. Groups (FASD vs. controls) were compared on fractional anisotropy (FA) and mean diffusivity (MD) in 6 white matter tracts projected through the corpus callosum. Exploratory analyses were also conducted examining the relationships between DTI measures in the corpus callosum and measures of intellectual functioning and facial dysmorphology.
In comparison with the control group, the FASD group had significantly lower FA in 3 posterior tracts of the corpus callosum: the posterior mid-body, the isthmus, and the splenium. A trend-level finding also suggested lower FA in the genu. Measures of white matter integrity and cognition were correlated and suggest some regional specificity, in that only posterior regions of the corpus callosum were associated with visual-perceptual skills. Correlations between measures of facial dysmorphology and posterior regions of the corpus callosum were nonsignificant.
Consistent with previous DTI studies, these results suggest that microstructural posterior corpus callosum abnormalities are present in children with prenatal alcohol exposure and cognitive impairment. These abnormalities are clinically relevant because they are associated with cognitive deficits and appear to provide evidence of abnormalities associated with prenatal alcohol exposure independent of dysmorphic features. As such, they may yield important diagnostic and prognostic information not provided by the traditional facial characteristics.
多项研究已通过弥散张量成像（DTI）显示，胎儿酒精谱系障碍（FASD）患儿的胼胝体异常，与未暴露组对照相比。数据表明，胼胝体的后部区域可能受到不成比例的影响。本研究建立在之前的努力基础上，包括我们自己的工作，并超越了胼胝体中线，通过一种改进的 DTI 轨迹方法来探测主要的半球间白质通路。这项研究还通过评估更大的样本量并纳入具有更广泛临床影响的儿童（包括全面标准的胎儿酒精综合征（FAS）），扩展了我们之前的工作。
参与者包括 33 名 FASD 患儿（8 名 FAS，23 名部分 FAS，2 名静止性脑病）和 19 名年龄在 10 至 17 岁之间的未暴露对照组。参与者接受 DTI 扫描和智力测试。在穿过胼胝体的 6 条白质束中，比较 FASD 组（FASD 与对照组）的各向异性分数（FA）和平均弥散度（MD）。还进行了探索性分析，检查胼胝体中的 DTI 测量值与智力功能和面部畸形的测量值之间的关系。
与对照组相比，FASD 组胼胝体的 3 个后部区域的 FA 明显降低：胼胝体中部、胼胝体体部和压部。FA 也有一个趋势水平降低，在胼胝体膝部。白质完整性和认知能力的测量值相关，提示存在一些区域特异性，即只有胼胝体的后部区域与视觉感知技能相关。面部畸形与胼胝体后部之间的相关性无统计学意义。
与之前的 DTI 研究一致，这些结果表明，在有产前酒精暴露和认知障碍的儿童中存在胼胝体后部微观结构异常。这些异常具有临床意义，因为它们与认知缺陷相关，并且似乎提供了与产前酒精暴露相关的异常证据，而与畸形特征无关。因此，它们可能提供传统面部特征无法提供的重要诊断和预后信息。
