Electrical Engineering and Computer Sciences, University of California, Berkeley; Brain Imaging and Analysis Center, Duke University School of Medicine, United States.
Neuroradiology, University of Oklahoma, United States.
Neurobiol Dis. 2018 Nov;119:79-87. doi: 10.1016/j.nbd.2018.07.020. Epub 2018 Jul 23.
To probe microstructural changes that are associated with subconcussive head impact exposure in deep and cortical gray matter of high school football players over a single season.
Players underwent diffusion kurtosis imaging (DKI) and quantitative susceptibility mapping (QSM) scans. Head impact data was recorded. Association between parametric changes and frequency of frontal head impact was assessed.
In deep gray matter, significant decreases in mean kurtosis (MK) and increases in mean diffusivity (MD) over the season were observed in the thalamus and putamen. Correlations between changes in DKI metrics and frequency of frontal impacts were observed in the putamen and caudate. In cortical gray matter, decreases in MK were observed in regions including the pars triangularis and inferior parietal. In addition, increases in MD were observed in the rostral middle frontal cortices. Negative correlations between MK and frequency of frontal impacts were observed in the posterior part of the brain including the pericalcarine, lingual and middle temporal cortices. Magnetic susceptibility values exhibited no significant difference or correlation, suggesting these diffusion changes common within the group may not be associated with iron-related mechanisms.
Microstructural alterations over the season and correlations with head impacts were captured by DKI metrics, which suggested that DKI imaging of gray matter may yield valuable biomarkers for evaluating brain injuries associated with subconcussive head impact. Findings of associations between frontal impacts and changes in posterior cortical gray matter also indicated that contrecoup injury rather than coup injury might be the dominant mechanism underlying the observed microstructural alterations.
Significant microstructural changes, as reflected by DKI metrics, in cortical gray matter such as the rostral middle frontal cortices, and in deep gray matter such as the thalamus were observed in high school football players over the course of a single season without clinically diagnosed concussion. QSM showed no evidence of iron-related changes in the observed subconcussive brain injuries. The detected microstructural changes in cortical and deep gray matter correlated with frequency of subconcussive head impacts.
DKI may yield valuable biomarkers for evaluating the severity of brain injuries associated with subconcussive head impacts in contact sport athletes.
探究与高中足球运动员单次赛季内亚脑震荡性头部撞击相关的脑深部和皮质灰质的微观结构变化。
运动员接受扩散峰度成像（DKI）和定量磁化率映射（QSM）扫描。记录头部撞击数据。评估参数变化与额部头部撞击频率之间的关联。
在深部灰质中，丘脑和壳核在整个赛季中观察到平均峰度（MK）显著降低，平均扩散率（MD）增加。在壳核和尾状核中观察到 DKI 指标变化与额部撞击频率之间的相关性。在皮质灰质中，观察到包括三角部和下顶叶在内的区域 MK 降低。此外，在额中回前部观察到 MD 增加。在后脑区域，包括距状回、舌回和颞中回，观察到 MK 与额部撞击频率之间的负相关。磁化率值无显著差异或相关性，表明这些在组内普遍存在的扩散变化可能与铁相关机制无关。
DKI 指标捕捉到了整个赛季的微观结构变化以及与头部撞击的相关性，这表明灰质的 DKI 成像可能为评估与亚脑震荡性头部撞击相关的脑损伤提供有价值的生物标志物。额部撞击与后部皮质灰质变化之间的关联发现也表明，对冲伤而不是打击伤可能是观察到的微观结构改变的主要机制。
在高中足球运动员中，在一个赛季内没有临床诊断的脑震荡的情况下，观察到皮质灰质（如额中回前部）和深部灰质（如丘脑）的 DKI 指标显著微观结构变化，以及深部灰质的微观结构变化。QSM 未显示观察到的亚脑震荡性脑损伤与铁相关变化的证据。皮质和深部灰质的检测到的微观结构变化与亚脑震荡性头部撞击频率相关。
DKI 可能为评估接触性运动运动员亚脑震荡性头部撞击相关脑损伤的严重程度提供有价值的生物标志物。
