Pediatric TBI and DAI: Normal Appearing Brain is Not Normal

描述（由申请人提供）：我们正在使用两种有前途的MR技术敏感性-加权成像（SWI）和磁共振光谱成像（MRSI），在TBI后早期获得，通过显示常规MRI显示正常的大脑损伤，以及SWI/MRSI单独或联合将更好地预测3个月和12个月的神经学（NL）和神经心理学（NP）结果，来确定它们是否能更好地评估TBI严重程度。在这个修订申请中，我们建议将DTI添加到我们的成像协议中。DTI提供了关于组织水扩散程度和方向性的额外信息；表观扩散系数（ADC）、分数各向异性（FA）和轴向扩散系数（||）均随轴突损伤而降低，反映了水沿白质束的扩散受到干扰；径向扩散系数（）随损伤而增加，反映了水在轴突纤维中的扩散增加。我们将利用3D SWI/MRSI/DTI对90名（4-18岁）中度/重度（GCS< 13） TBI儿童（损伤后7-17天）和90名对照组的11个大脑区域进行评估。测量结果将进行区域、全局（所有区域合并）和3个脑区（皮质、皮质下和后窝）的比较。我们的目标是：1)证明与临床指标相比，DTI参数可以检测轴突损伤，并改善3个月和12个月NL/NP预后预测；2)确定SWI/MRSI/DTI数据是否单独或组合更准确地预测结果；3)在12个月时重复SWI/MRSI/DTI，对损伤模式进行分类，定义为神经元变性、恢复和可塑性，通过与整体功能结果相关的NAA或DTI参数的间隔变化来衡量，并探讨出血性SWI病变是否仍然存在。目前的成像技术无法识别儿童脑损伤的程度，因此，这对了解损伤的真实严重程度、做出治疗决定和预测预后有很大的不利影响。添加DTI将提供额外的直接测量轴索损伤和额外的信息来评估儿童TBI。

DESCRIPTION (provided by applicant): We are using two promising MR techniques Susceptibility- Weighted Imaging (SWI) and Magnetic Resonance Spectroscopic Imaging (MRSI), acquired early after TBI to determine whether they are better at evaluating TBI severity by showing that injury is present in brain that appears normal with conventional MRI and that SWI/MRSI individually or combined will better predict 3- and 12-month neurological (NL) and neuropsychological (NP) outcome. In this revision application, we propose adding DTI to our imaging protocol. DTI provides additional information regarding the degree and directionality of tissue water diffusion; the apparent diffusion coefficient (ADC), fractional anisotropy (FA), and axial diffusivity (||) all of which decrease with axonal injury that reflects disturbed water diffusion along white matter tracts and radial diffusivity () which increases with injury and reflects increased water diffusion across axonal fibers We will acquire 3D SWI/MRSI/DTI to evaluate 11 brain regions in 90 children (4-18 years) with moderate/severe (GCS< 13) TBI, 7-17 days after injury and 90 controls. Measurements will be compared regionally, globally (all regions combined) and as 3 pooled brain regions (cortical, subcortical, and posterior fossa). Our aims are to: 1) demonstrate that DTI parameters will detect axonal injury and improve 3 and 12- month NL/NP outcome prediction compared to clinical indicators; 2) determine whether SWI/MRSI/DTI data individually or in combination are more accurate for predicting outcome; and 3) repeat SWI/MRSI/DTI at 12 months to categorize patterns of injury, defined as neuronal degeneration, recovery and plasticity measured by interval changes of NAA or DTI parameters associated with global functional outcomes and to explore whether hemorrhagic SWI lesions are still present. Current imaging techniques fail to recognize the extent of TBI in children and as a result, this has significant untoward effects regarding understanding the true severity of injury, making treatment decisions and in being able to predict prognosis. Adding DTI will provide additional direct measures of axonal injury and additional information to evaluate children with TBI. PUBLIC HEALTH RELEVANCE: Current imaging techniques underestimate or fail to recognize the extent of TBI in children which has significant untoward effects regarding understanding the true severity of injury. Diffusion Tensor Imaging will be used with other more sensitive imaging techniques (SWI and MRSI) to improve injury detection in brain that may appear normal. We believe that success of this grant will result in a paradigm shift in how children will be evaluated after TBI that will improve neurological outcome and quality of life.