Marchitelli Rocco, Collignon Olivier, Jovicich Jorge
1 Center for Mind/Brain Sciences (CIMEC), University of Trento , Rovereto, Italy .
2 I.R.C.C.S. SDN, Naples, Italy .
Brain Connect. 2017 Mar;7(2):69-83. doi: 10.1089/brain.2016.0450. Epub 2017 Feb 23.
Head motion is a known challenge in resting-state functional magnetic resonance imaging studies for biasing functional connectivity (FC) among distinct anatomical regions. These persist even with small motion, limiting comparisons of groups with different head-motion characteristics. This motivates an interest in the optimization of acquisition and correction strategies to minimize motion sensitivity. In this test-retest (TRT) study of healthy young volunteers (N = 23), we investigate the effects of slice-order acquisitions (sequential or interleaved) and head-motion correction methods (volume- or slice-based) on the TRT reproducibility of intrinsic connectivity of the default mode network (DMN). We evaluated the TRT reproducibility of the entire DMN and each main node using the absolute percentage error, intraclass correlation coefficient (ICC), and the Jaccard coefficient. Regardless of slice-order acquisition, the slice-based motion correction method systematically estimated larger motion and returned significantly higher temporal signal-to-noise ratio. Although consistently extracted across all acquisition and motion correction approaches, DMN connectivity was sensitive to these choices. However, the TRT reproducibility of the whole DMN was stable and showed no sensitivity to the methods tested (absolute reproducibility ∼7%, ICC = 0.47, and Jaccard = 40%). Percentage errors and ICCs were consistent across single nodes, but the Jaccard coefficients were not. The posterior cingulate was the most reproducible node (Jaccard = 52%), whereas the anterior cingulate was the least reproducible (Jaccard = 30%). Our study suggests that the slice-order and motion correction methods evaluated offer comparable sensitivity to detect DMN connectivity changes in a longitudinal study of individuals with low head-motion characteristics, but that controlling for the consistency in acquisition and correction protocols is important in cross-sectional studies.
在静息态功能磁共振成像研究中，头部运动是一个已知的挑战，它会影响不同解剖区域之间的功能连接（FC）。即使是轻微的运动，这些影响依然存在，这限制了对具有不同头部运动特征的组进行比较。这激发了人们对优化采集和校正策略以最小化运动敏感性的兴趣。在这项针对健康年轻志愿者（N = 23）的重测（TRT）研究中，我们研究了切片顺序采集（顺序或交错）和头部运动校正方法（基于体积或基于切片）对默认模式网络（DMN）内在连接性的TRT可重复性的影响。我们使用绝对百分比误差、组内相关系数（ICC）和杰卡德系数评估了整个DMN和每个主要节点的TRT可重复性。无论切片顺序采集如何，基于切片的运动校正方法系统地估计出更大的运动，并返回显著更高的时间信噪比。尽管在所有采集和运动校正方法中都能一致地提取到DMN连接性，但它对这些选择很敏感。然而，整个DMN的TRT可重复性是稳定的，并且对所测试的方法不敏感（绝对可重复性约为7%，ICC = 0.47，杰卡德系数 = 40%）。单个节点的百分比误差和ICC是一致的，但杰卡德系数不一致。后扣带回是最具可重复性的节点（杰卡德系数 = 52%），而前扣带回是最不具可重复性的（杰卡德系数 = 30%）。我们的研究表明，在对头部运动特征较低的个体进行纵向研究时，所评估的切片顺序和运动校正方法在检测DMN连接性变化方面具有可比的敏感性，但在横断面研究中，控制采集和校正协议的一致性很重要。
