Moss Rehabilitation Research Institute, Albert Einstein Healthcare Network, Elkins Park, PA 19027, USA.
Neurorehabil Neural Repair. 2012 Sep;26(7):870-80. doi: 10.1177/1545968311434553. Epub 2012 Feb 22.
Given that traumatic brain injury (TBI) results in chronic alteration of baseline cerebral perfusion, a perfusion functional MRI (fMRI) method that dissociates resting- and task-related cerebral blood flow (CBF) changes can be useful in noninvasively investigating the neural correlates of cognitive dysfunction and recovery in TBI.
The authors used continuous arterial spin-labeled (ASL) perfusion fMRI to characterize CBF at rest and during sustained-attention and working-memory tasks.
A total of 18 to 21 individuals with moderate to severe TBI and 14 to 18 demographically matched healthy controls completed 3 continuous 6-minute perfusion fMRI scans (resting, visual sustained attention, and 2-back working memory).
For both tasks, TBI participants showed worse behavioral performance than controls. Voxelwise neuroimaging analysis of the 2-back task found that group differences in task-induced CBF changes were localized to bilateral superior occipital cortices and the left superior temporal cortex. Whereas controls deactivated these areas during task performance, TBI participants tended to activate these same areas. These regions were among those found to be disproportionately hypoperfused at rest after TBI. For both tasks, the control and TBI groups showed different patterns of correlation between performance and task-related CBF changes.
ASL perfusion fMRI demonstrated differences between individuals with TBI and healthy controls in resting perfusion and in task-evoked CBF changes as well as different patterns of performance-activation correlation. These results are consistent with the notion that sensory/attentional modulation deficits contribute to higher cognitive dysfunction in TBI.
由于创伤性脑损伤（TBI）导致基础脑灌注的慢性改变，一种能够区分静息和任务相关脑血流（CBF）变化的灌注功能磁共振成像（fMRI）方法可用于无创性研究 TBI 患者认知功能障碍和恢复的神经相关性。
作者使用连续动脉自旋标记（ASL）灌注 fMRI 来描述静息和持续注意力及工作记忆任务期间的 CBF。
共有 18 至 21 名中度至重度 TBI 患者和 14 至 18 名年龄匹配的健康对照者完成了 3 次连续 6 分钟的灌注 fMRI 扫描（静息、视觉持续注意力和 2 回工作记忆）。
对于两项任务，TBI 患者的行为表现均差于对照组。2 回任务的全脑影像分析发现，组间任务诱发 CBF 变化的差异局限于双侧顶枕叶皮质和左侧颞上回。而对照组在任务执行期间这些区域表现为去激活，TBI 患者则倾向于激活这些相同的区域。这些区域是 TBI 后静息状态下过度灌注的区域之一。对于两项任务，对照组和 TBI 组的表现与任务相关的 CBF 变化之间的相关性存在不同的模式。
ASL 灌注 fMRI 显示 TBI 患者和健康对照者在静息灌注和任务诱发 CBF 变化方面存在差异，以及表现与激活相关性的不同模式。这些结果与感觉/注意力调节缺陷导致 TBI 患者更高认知功能障碍的观点一致。
