Conti Eugenia, Pannek Kerstin, Calderoni Sara, Gaglianese Anna, Fiori Simona, Brovedani Paola, Scelfo Danilo, Rose Stephen, Tosetti Michela, Cioni Giovanni, Guzzetta Andrea
Funct Neurol. 2015 Jul-Sep;30(3):203-8. doi: 10.11138/fneur/2015.30.3.203.
In recent years, the use of brain diffusion MRI has led to the hypothesis that children with autism spectrum disorder (ASD) show abnormally connected brains. We used the model of disease-discordant identical twins to test the hypothesis that higher-order diffusion MRI protocols are able to detect abnormal connectivity in a single subject. We studied the structural connectivity of the brain of a child with ASD, and of that of his unaffected identical twin, using high angular resolution diffusion imaging (HARDI) probabilistic tractography. Cortical regions were automatically parcellated from high-resolution structural images, and HARDI-based connection matrices were produced for statistical comparison. Differences in diffusion indexes between subjects were tested by Wilcoxon signed rank test. Tracts were defined as discordant when they showed a between-subject difference of 10 percent or more. Around 11 percent of the discordant intra-hemispheric tracts showed lower fractional anisotropy (FA) values in the ASD twin, while only 1 percent showed higher values. This difference was significant. Our findings in a disease-discordant identical twin pair confirm previous literature consistently reporting lower FA values in children with ASD.
近年来，脑扩散磁共振成像（MRI）的应用引发了一种假说，即自闭症谱系障碍（ASD）儿童的大脑存在异常连接。我们使用疾病不一致的同卵双胞胎模型来检验高阶扩散MRI方案能够检测单个受试者异常连接的假说。我们使用高角分辨率扩散成像（HARDI）概率纤维束成像技术研究了一名患有ASD儿童及其未受影响的同卵双胞胎的大脑结构连接性。从高分辨率结构图像中自动分割出皮质区域，并生成基于HARDI的连接矩阵用于统计比较。通过Wilcoxon符号秩检验来检验受试者之间扩散指数的差异。当纤维束在受试者之间的差异达到10%或更大时，将其定义为不一致。在半球内不一致的纤维束中，约11%在患有ASD的双胞胎中显示出较低的各向异性分数（FA）值，而只有1%显示出较高的值。这种差异具有显著性。我们在一对疾病不一致的同卵双胞胎中的研究结果证实了先前文献中一致报道的ASD儿童FA值较低这一情况。
