In recent years a number of semi-automated and automated segmentation tools and brain atlases have been developed to facilitate morphometric analyses of large MRI datasets. These tools are much faster than manual tracing and demonstrate excellent test–retest reliabilities. Reliabilities of automated segmentations relative to “gold standard” manual tracings have, however, been shown to vary by brain region and in different cohorts. It remains uncertain to what extent smaller brain volumes and potential changes in grey/white matter contrasts in paediatric brains impact on the performance of automated methods, and how pathology may influence performance. This study examined whether using data from automated FreeSurfer segmentation would alter our ability, compared to manual segmentation, to detect prenatal alcohol exposure (PAE)-related volume changes in subcortical regions and the corpus callosum (CC) in pre-adolescent children. High-resolution T1-weighted images were acquired, using a sequence optimized for morphometric neuroanatomical analysis, on a Siemens 3T Allegra MRI scanner in 71 right-handed, 9- to 11-year-old children (27 fetal alcohol syndrome (FAS) and partial FAS (PFAS), 25 non-syndromal heavily exposed (HE) and 19 non-exposed controls) from a high-risk community in Cape Town, South Africa. Data from timeline follow-back interviews administered to the mothers prospectively during pregnancy were used to quantify the amount of alcohol (in ounces absolute alcohol per day, AA/day) that the children had been exposed to prenatally. Volumes of corpus callosum (CC) and bilateral caudate nuclei, hippocampi and nucleus accumbens (NA) were obtained by manual tracing and automated segmentation using both FreeSurfer versions 5.1 and 6.0. Reliability across methods was assessed using intraclass correlation (ICC) estimates for consistency and absolute agreement, and Cronbach’s α. Ability to detect regions showing PAE effects was assessed separately for each segmentation method using ANOVA and linear regression of regional volumes with AA/day. Our results support findings from other studies showing excellent reliability across methods for easy-to-segment structures, such as the CC and caudate nucleus. Volumes from FreeSurfer 6.0 were smaller than those from version 5.1 in all regions except the right caudate, for which they were similar, and right hippocampus and CC, for which they were larger. Despite poor absolute agreement between methods in the NA and hippocampus, all three segmentation methods detected dose-dependent volume reductions in regions for which reliabilities on ICC consistency across methods reached at least 0.70, namely the CC, and bilateral caudate nuclei and hippocampi. PAE-related changes in the NA for which ICC consistency did not reach this minimum were inconsistent across methods and should be interpreted with caution. This is the first study to demonstrate in a pre-adolescent cohort the ability of automated segmentation with FreeSurfer to detect regional volume changes associated with pathology similar to those found using manual tracing.

近年来，已经开发了许多半自动和自动分割工具以及脑图谱，以促进大型MRI数据集的形态分析。这些工具比手动跟踪要快得多，并且证明了极好的测试-重新测试可靠性。但是，相对于“黄金标准”手动跟踪，自动分段的可靠性已显示因大脑区域和不同人群而异。尚不确定小儿大脑体积的缩小以及小儿脑中灰色/白色物质对比的潜在变化会在何种程度上影响自动化方法的性能，以及病理学如何影响性能。这项研究调查了与手动细分相比，使用自动FreeSurfer细分中的数据是否会改变我们的能力，检测青春期前儿童皮质下区域和sub体（CC）与产前酒精暴露（PAE）相关的体积变化。在71位右撇子9至11岁儿童（27名胎儿酒精综合症（FAS）和71名右撇子）中，使用针对形态计量神经解剖分析优化的序列在Siemens 3T Allegra MRI扫描仪上获得了高分辨率的T1加权图像。来自南非开普敦高风险社区的部分FAS（PFAS），25个非综合征重度暴露（HE）和19个非暴露对照）。孕妇在怀孕期间前瞻性地对母亲进行的时间表随访访问中的数据用于量化孩子出生前所接触的酒精量（每天盎司绝对酒精，AA /天）。call体（CC）和双侧尾状核的体积，使用FreeSurfer版本5.1和6.0通过手动跟踪和自动分割获得海马和伏隔核（NA）。使用类内相关性（ICC）估计的一致性和绝对一致性以及Cronbach的α评估方法之间的可靠性。使用ANOVA对每种分割方法分别评估检测显示PAE效应的区域的能力，并使用AA /天对区域体积进行线性回归。我们的结果支持其他研究的结果，这些结果表明，对于易于分割的结构（例如CC和尾状核），各种方法均具有出色的可靠性。FreeSurfer 6.0的体积在所有区域都比5.1版本的体积小，除了右尾状体（它们相似）以及右海马和CC（它们较大）之外。尽管NA和海马中的方法之间的绝对一致性差，但所有三种分割方法均在剂量依赖性体积减小的区域中发现，这些区域中跨方法对ICC一致性的可靠性至少达到0.70，即CC，双侧尾状核和海马。在各方法中，ICC一致性未达到此最小值的NA中PAE相关的更改不一致，应谨慎解释。这是第一项在青少年前期研究中证明使用FreeSurfer进行自动分割的功能，以检测与病理学相关的区域体积变化的能力，类似于使用手动追踪发现的变化。所有这三种分割方法均检测到区域间剂量依赖性体积的减少，在这些区域中，各方法对ICC一致性的可靠性至少达到0.70，即CC，双侧尾状核和海马体。在各方法中，ICC一致性未达到此最小值的NA中PAE相关的更改不一致，应谨慎解释。这是第一项在青少年前期研究中证明使用FreeSurfer进行自动分割的功能，以检测与病理学相关的区域体积变化的能力，类似于使用手动追踪发现的变化。所有这三种分割方法均检测到区域间剂量依赖性体积的减少，在这些区域中，各方法对ICC一致性的可靠性至少达到0.70，即CC，双侧尾状核和海马体。在各方法中，ICC一致性未达到此最小值的NA中与PAE相关的更改不一致，应谨慎对待。这是第一项在青少年前期研究中证明使用FreeSurfer进行自动分割的功能，以检测与病理学相关的区域体积变化的能力，类似于使用手动追踪发现的变化。