Semel Institute for Neuroscience and Human Behavior Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California-Los Angeles, 760 Westwood Plaza, Room C8-746, Los Angeles, CA 90095, USA.
J Neurotrauma. 2010 Mar;27(3):473-81. doi: 10.1089/neu.2009.1058.
Diffuse axonal injury (DAI) secondary to traumatic brain injury (TBI) contributes to long-term functional morbidity. The corpus callosum (CC) is particularly vulnerable to this type of injury. Magnetic resonance spectroscopy (MRS) was used to characterize the metabolic status of two CC regions of interest (ROIs) (anterior and posterior), and their structural (diffusion tensor imaging; DTI) and neurobehavioral (neurocognitive functioning, bimanual coordination, and interhemispheric transfer time [IHTT]) correlates. Two groups of moderate/severe TBI patients (ages 12-18 years) were studied: post-acute (5 months post-injury; n = 10), and chronic (14.7 months post-injury; n = 8), in addition to 10 age-matched healthy controls. Creatine (energy metabolism) did not differ between groups across both ROIs and time points. In the TBI group, choline (membrane degeneration/inflammation) was elevated for both ROIs at the post-acute but not chronic period. N-acetyl aspartate (NAA) (neuronal/axonal integrity) was reduced initially for both ROIs, with partial normalization at the chronic time point. Posterior, not anterior, NAA was positively correlated with DTI fractional anisotropy (FA) (r = 0.88), and most domains of neurocognition (r range 0.22-0.65), and negatively correlated with IHTT (r = -0.89). Inverse corerlations were noted between creatine and posterior FA (r = -0.76), neurocognition (r range -0.22 to -0.71), and IHTT (r = 0.76). Multimodal studies at distinct time points in specific brain structures are necessary to delineate the course of the degenerative and reparative processes following TBI, which allows for preliminary hypotheses about the nature and course of the neural mechanisms of subsequent functional morbidity. This will help guide the future development of targeted therapeutic agents.
创伤性脑损伤（TBI）继发的弥漫性轴索损伤（DAI）导致长期功能障碍。胼胝体（CC）特别容易受到这种类型的损伤。磁共振波谱（MRS）用于描述两个感兴趣的胼胝体区域（前部和后部）的代谢状态，以及它们的结构（弥散张量成像；DTI）和神经行为（神经认知功能、双手协调和半球间转移时间[IHTT]）相关性。研究了两组中度/重度 TBI 患者（年龄 12-18 岁）：急性后（损伤后 5 个月；n = 10）和慢性（损伤后 14.7 个月；n = 8），此外还有 10 名年龄匹配的健康对照者。在两个 ROI 和时间点上，各组之间的肌酸（能量代谢）没有差异。在 TBI 组中，两个 ROI 在急性后期但不在慢性期时，胆碱（膜退化/炎症）升高。在两个 ROI 中，N-乙酰天冬氨酸（NAA）（神经元/轴突完整性）最初降低，在慢性时间点部分恢复正常。后部，而不是前部，NAA 与 DTI 各向异性分数（FA）呈正相关（r = 0.88），与神经认知的大多数领域呈正相关（r 范围 0.22-0.65），与 IHTT 呈负相关（r = -0.89）。在后部，而不是前部，观察到肌酸与后部 FA（r = -0.76）、神经认知（r 范围 -0.22 至 -0.71）和 IHTT（r = 0.76）之间存在负相关。在特定脑结构的不同时间点进行的多模态研究对于描绘 TBI 后退行性和修复性过程的过程是必要的，这使得我们可以对随后的功能障碍的神经机制的性质和过程提出初步假设。这将有助于指导靶向治疗药物的未来发展。
