1 Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, California.
2 Department of Clinical Science, Child- and Adolescent Psychiatry, Umeå University, Umeå, Sweden.
Brain Connect. 2019 Mar;9(2):144-154. doi: 10.1089/brain.2018.0580. Epub 2018 Dec 26.
Graph theory analysis of structural brain networks derived from diffusion tensor imaging (DTI) has become a popular analytical method in neuroscience, enabling advanced investigations of neurological and psychiatric disorders. The purpose of this study was to investigate (1) the effects of edge weighting schemes and (2) the effects of varying interscan periods on graph metrics within the adolescent brain. We compared a binary (B) network definition with three weighting schemes: fractional anisotropy (FA), streamline count, and streamline count with density and length correction (SDL). Two commonly used global and two local graph metrics were examined. The analysis was conducted with two groups of adolescent volunteers who received DTI scans either 12 weeks apart (16.62 ± 1.10 years) or within the same scanning session (30 min apart) (16.65 ± 1.14 years). The intraclass correlation coefficient was used to assess test-retest reliability and the coefficient of variation (CV) was used to assess precision. On average, each edge scheme produced reliable results at both time intervals. Weighted measures outperformed binary measures, with SDL weights producing the most reliable metrics. All edge schemes except FA displayed high CV values, leaving FA as the only edge scheme that consistently showed high precision while also producing reliable results. Overall findings suggest that FA weights are more suited for DTI connectome studies in adolescents.
基于弥散张量成像（DTI）的脑结构网络的图论分析已经成为神经科学中一种流行的分析方法，能够对神经和精神疾病进行深入研究。本研究旨在探讨（1）边缘权重方案的影响，以及（2）不同扫描间隔对青少年大脑中图度量的影响。我们比较了二值（B）网络定义和三种权重方案：各向异性分数（FA）、轨迹计数和带密度和长度校正的轨迹计数（SDL）。研究了两种常用的全局和局部图度量。分析了两组青少年志愿者的数据，他们分别在 12 周（16.62±1.10 岁）或同一扫描会话（30 分钟）（16.65±1.14 岁）内接受 DTI 扫描。使用组内相关系数评估测试-重测可靠性，使用变异系数（CV）评估精度。平均而言，每种边缘方案在两个时间间隔都产生了可靠的结果。加权测量优于二值测量，SDL 权重产生了最可靠的指标。除 FA 外，所有边缘方案的 CV 值都很高，FA 成为唯一一种始终显示高精度且同时产生可靠结果的边缘方案。总体研究结果表明，FA 权重更适合青少年 DTI 连接组学研究。
