Dynamic association between perfusion and white matter integrity across time since injury in Veterans with history of TBI.
Dynamic association between perfusion and white matter integrity across time since injury in Veterans with history of TBI.
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DOI：
10.1016/j.nicl.2016.12.017
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Delano-Wood L
中科院分区：
文献类型：
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作者：
Clark AL;Bangen KJ;Sorg SF;Schiehser DM;Evangelista ND;McKenna B;Liu TT;Delano-Wood L
脑血流量(CBF)在维持神经元完整性方面起着至关重要的作用，而CBF的改变与有害的脑白质改变有关。虽然在创伤性脑损伤(TBI)的背景下观察到了CBF和白质微结构的变化，但这些病理变化相互关联的程度以及这种关联自损伤以来是否随着时间的推移而改变还没有被研究过。因此，目前的研究试图澄清静息脑血流量与脑外伤后脑白质微结构之间的关系。对37例有轻中度颅脑损伤病史的退伍军人进行神经成像检查，并填写健康和精神症状问卷。用多时相伪连续动脉自旋标记(MPPCASL)测量静息脑血流，用弥散张量成像(DTI)测量脑白质微结构完整性。鉴于扣带皮质和扣带束对脑损伤的易感性，分别选择这些区域作为ASL和DTI数据的先验感兴趣区域。控制年龄、性别和创伤后应激障碍(PTSD)症状的回归分析显示，左侧扣带回自受伤以来的显著时间×静息脑血流量的交互作用(P<0.005)。在慢性期，CBF减少与扣带部分各向异性(FA)减少显著相关；然而，对于远期脑损伤较少的参与者，没有观察到这种关联。我们的结果表明，在那些进一步远离脑损伤的人中，脑血流量减少与脑白质完整性较差有关。研究结果为脑血流和脑白质微结构之间可能的动态关联提供了初步证据，在有脑外伤病史的患者中经常观察到的长期负面临床结果的背景下，这一关联值得进一步考虑。需要更多的跨学科研究，结合多种成像方式(例如，DTI、ASL)和改进的神经精神病学评估，以更好地了解损伤后脑变化和临床结果之间的性质、时间进程和动态关联。通常没有考虑的是(1)感兴趣的大脑变量之间的动态关系，以及(2)自受伤以来的时间如何影响大脑的变化。脑血流量(CBF)在维持神经元完整性方面起着至关重要的作用，而CBF的改变与有害的白质(WM)改变有关。虽然CBF和WM的改变都是在脑外伤的情况下观察到的，但这些病理改变相互关联的程度还没有被研究过。这一点尤其重要，因为CBF的减少可能会加剧或促进任何创伤引起的WM改变，远远超过最初受伤的时间。本研究探讨了有脑外伤病史的退伍军人CBF和WM之间的关系，以及伤后时间对这种关系的潜在影响。结果表明，损伤时间与左侧扣带回脑血流量对左侧扣带回WM完整性有交互作用。这些发现可能有助于阐明在有脑外伤病史的患者中观察到的不良长期结果背后的机制。
Cerebral blood flow (CBF) plays a critical role in the maintenance of neuronal integrity, and CBF alterations have been linked to deleterious white matter changes. Although both CBF and white matter microstructural alterations have been observed within the context of traumatic brain injury (TBI), the degree to which these pathological changes relate to one another and whether this association is altered by time since injury have not been examined. The current study therefore sought to clarify associations between resting CBF and white matter microstructure post-TBI. 37 veterans with history of mild or moderate TBI (mmTBI) underwent neuroimaging and completed health and psychiatric symptom questionnaires. Resting CBF was measured with multiphase pseudocontinuous arterial spin labeling (MPPCASL), and white matter microstructural integrity was measured with diffusion tensor imaging (DTI). The cingulate cortex and cingulum bundle were selected as a priori regions of interest for the ASL and DTI data, respectively, given the known vulnerability of these regions to TBI. Regression analyses controlling for age, sex, and posttraumatic stress disorder (PTSD) symptoms revealed a significant time since injury × resting CBF interaction for the left cingulum (p < 0.005). Decreased CBF was significantly associated with reduced cingulum fractional anisotropy (FA) in the chronic phase; however, no such association was observed for participants with less remote TBI. Our results showed that reduced CBF was associated with poorer white matter integrity in those who were further removed from their brain injury. Findings provide preliminary evidence of a possible dynamic association between CBF and white matter microstructure that warrants additional consideration within the context of the negative long-term clinical outcomes frequently observed in those with history of TBI. Additional cross-disciplinary studies integrating multiple imaging modalities (e.g., DTI, ASL) and refined neuropsychiatric assessment are needed to better understand the nature, temporal course, and dynamic association between brain changes and clinical outcomes post-injury. Oftentimes unconsidered are (1) the dynamic relationship between brain variables of interest and (2) how time since injury may factor into brain changes. Cerebral blood flow (CBF) plays a critical role in the maintenance of neuronal integrity, and CBF alterations have been linked to deleterious white matter (WM) changes. Although both CBF and WM alterations have been observed within the context of TBI, the degree to which these pathological changes relate to one another has not been examined. This is especially critical given CBF reductions could serve to exacerbate or contribute to any trauma-induced WM alterations well beyond the time of initial injury. The current study explored the association between CBF and WM, and the potential influence of time since injury on this relationship in Veterans with history of TBI. Results showed an interaction between time since injury and CBF of the left cingulate cortex on WM integrity of the left cingulum bundle. These findings may assist in clarifying mechanisms underlying the poor long-term outcomes observed in those with history of TBI.