轻度创伤性脑损伤中小世界属性的变化。
Small world properties changes in mild traumatic brain injury.
机构信息
Department of Radiology / Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York.
出版信息
J Magn Reson Imaging. 2017 Aug;46(2):518-527. doi: 10.1002/jmri.25548. Epub 2016 Nov 30.
PURPOSE
To investigate local and global efficiency changes characterized by small-world properties based on resting-state functional MRI, such as centrality and clustering coefficient, in mild traumatic brain injury (MTBI) patients; and to associate these findings with axonal injury as measured by diffusion tensor imaging (DTI) as well as with post-concussive symptom (PCS).
MATERIALS AND METHODS
Thirty patients (mean age 35 ± 13 years) with clinically defined MTBI and 45 age-matched healthy controls (mean age 37 ± 10 years) participated in the experiments. Resting-state functional MRI was performed using gradient echo planar imaging sequence with 3 Tesla MRI scanner to obtain functional small-world networks. Out of all participants, 20 MTBI patients and 20 controls had available DTI data with three b-values (0, 500, 1000) s/mm and 30 directions for diffuse axonal injury analyses.
RESULTS
Compared with controls, MTBI patients showed lower relative betweenness centrality (P = 0.01), but significantly higher clustering coefficient (P = 0.04), and these two metrics correlated negatively in patients (r = -0.77; P < 0.001). Regions with lower betweenness centrality (e.g., frontal and occipital) corresponded with the regions of reduced FA in patients, while global FA reduction correlated with betweenness centrality (r = 0.48; P = 0.03) and clustering coefficient (r = -0.46; P = 0.04) in MTBI patients. In addition, there was significantly higher thalamocortical connectivity that correlated with clustering coefficient (r = 0.39; P = 0.03) in patients. Also, patients with higher clustering coefficient tended to have less PCS score with negative correlation (r = -0.4; P = 0.04).
CONCLUSION
Our results demonstrated significant functional small-world properties changes in patients with MTBI, and suggest decreased global efficiency, possibly due to diffuse axonal injury and local network upregulation including increased thalamo-cortical connectivity.
LEVEL OF EVIDENCE
2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:518-527.
目的
利用静息态功能磁共振成像（rs-fMRI），研究轻度创伤性脑损伤（MTBI）患者的局部和全局效率变化特征，这些特征表现为小世界属性，包括中枢性和聚类系数；并将这些发现与扩散张量成像（DTI）测量的轴突损伤以及与脑震荡后症状（PCS）相关联。
材料与方法
30 名患者（平均年龄 35±13 岁）和 45 名年龄匹配的健康对照者（平均年龄 37±10 岁）参与了该实验。使用梯度回波平面成像序列在 3T MRI 扫描仪上进行 rs-fMRI，以获得功能小世界网络。在所有参与者中，20 名 MTBI 患者和 20 名对照者具有可用的 DTI 数据，有三个 b 值（0、500、1000）s/mm 和 30 个扩散张量成像分析方向。
结果
与对照组相比，MTBI 患者的相对介数中心度较低（P=0.01），但聚类系数明显较高（P=0.04），而且这两个指标在患者中呈负相关（r=-0.77；P<0.001）。介数中心度较低的区域（如额叶和枕叶）与患者 FA 降低的区域相对应，而整体 FA 降低与 MTBI 患者的介数中心度（r=0.48；P=0.03）和聚类系数（r=-0.46；P=0.04）呈正相关。此外，患者的丘脑皮质连接性显著升高，与聚类系数呈正相关（r=0.39；P=0.03）。此外，聚类系数较高的患者 PCS 评分较低，两者呈负相关（r=-0.4；P=0.04）。
结论
我们的研究结果表明，MTBI 患者存在显著的功能小世界属性变化，表明全局效率降低，可能是由于弥漫性轴索损伤和局部网络上调，包括丘脑皮质连接增加。
证据水平
2 技术功效：2 级。J. MAGN. RESON. IMAGING 2017；46：518-527。
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