Abstract This study compared findings from whole-brain diffusion tensor imaging (DTI) and volumetric magnetic resonance imaging (MRI) among 90 Active Duty Service Members with chronic mild traumatic brain injury (TBI; n = 52), chronic moderate-to-severe TBI (n = 17), and TBI-negative controls (n = 21). Data were collected on a Philips Ingenia 3T MRI with DTI in 32 directions. Results demonstrated that history of TBI was associated with differences in white matter microstructure, white matter volume, and cortical thickness in both mild TBI and moderate-to-severe TBI groups relative to controls. However, the presence, pattern, and distribution of these findings varied substantially depending on the injury severity. Spatially-defined forms of DTI fractional anisotropy (FA) analyses identified altered white matter organization within the chronic moderate-to-severe TBI group, but they did not provide clear evidence of abnormalities within the chronic mild TBI group. In contrast, DTI FA "pothole" analyses identified widely distributed areas of decreased FA throughout the white matter in both the chronic mild TBI and chronic moderate-to-severe TBI groups. Additionally, decreased white matter volume was found in several brain regions for the chronic moderate-to-severe TBI group compared with the other groups. Greater number of DTI FA potholes and reduced cortical thickness were also related to greater severity of self-reported symptoms. In sum, this study expands upon a growing body of literature using advanced imaging techniques to identify potential effects of brain injury in military Service Members. These findings may differ from work in other TBI populations due to varying mechanisms and frequency of injury, as well as a potentially higher level of functioning in the current sample related to the ability to maintain continued Active Duty status after injury. In conclusion, this study provides DTI and volumetric MRI findings across the spectrum of TBI severity. These results provide support for the use of DTI and volumetric MRI to identify differences in white matter microstructure and volume related to TBI. In particular, DTI FA pothole analysis may provide greater sensitivity for detecting subtle forms of white matter injury than conventional DTI FA analyses.

中文翻译：

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患有慢性轻度、中度和重度创伤性脑损伤的现役军人的白质组织和皮质厚度有所不同。

摘要：本研究比较了 90 名患有慢性轻度创伤性脑损伤 (TBI；n = 52)、慢性中度至重度 TBI 的现役军人的全脑扩散张量成像 (DTI) 和体积磁共振成像 (MRI) 的结果(n = 17) 和 TBI 阴性对照 (n = 21)。数据是在 Philips Ingenia 3T MRI 上收集的，具有 32 个方向的 DTI。结果表明，轻度 TBI 组和中重度 TBI 组相对于对照组的白质微观结构、白质体积和皮质厚度差异与 TBI 病史相关。然而，这些发现的存在、模式和分布根据损伤的严重程度而有很大差异。空间定义形式的 DTI 分数各向异性 (FA) 分析确定了慢性中度至重度 TBI 组中白质组织的改变，但没有提供慢性轻度 TBI 组中异常的明确证据。相比之下，DTI FA“坑洞”分析发现，在慢性轻度 TBI 和慢性中重度 TBI 组中，整个白质中 FA 减少的区域广泛分布。此外，与其他组相比，慢性中度至重度 TBI 组的几个大脑区域的白质体积减少。DTI FA 坑洞数量增多和皮质厚度减少也与自我报告症状更严重有关。总之，这项研究扩展了越来越多的文献，使用先进的成像技术来识别军人脑损伤的潜在影响。由于受伤机制和频率不同，以及当前样本中与受伤后维持持续现役状态的能力相关的潜在更高水平的功能，这些发现可能与其他 TBI 人群的研究有所不同。总之，本研究提供了 TBI 严重程度范围内的 DTI 和体积 MRI 结果。这些结果为使用 DTI 和体积 MRI 来识别与 TBI 相关的白质微观结构和体积差异提供了支持。特别是，与传统的 DTI FA 分析相比，DTI FA 坑洞分析可以为检测细微形式的白质损伤提供更高的灵敏度。