There is evidence that diffusion-weighted imaging (DWI) is able to detect tissue alterations following mild traumatic brain injury (mTBI) that may not be observed on conventional neuroimaging; however, findings are often inconsistent between studies. This systematic review assesses patterns of differences in DWI metrics between those with and without a history of mTBI. A PubMed literature search was performed using relevant indexing terms for articles published prior to May 14, 2020. Findings were limited to human studies using DWI in mTBI. Articles were excluded if they were not full-length, did not contain original data, if they were case studies, pertained to military populations, had inadequate injury severity classification, or did not report post-injury interval. Findings were reported independently for four subgroups: acute/subacute pediatric mTBI, acute/subacute adult mTBI, chronic adult mTBI, and sport-related concussion, and all DWI acquisition and analysis methods used were included. Patterns of findings between studies were reported, along with strengths and weaknesses of the current state of the literature. Although heterogeneity of sample characteristics and study methods limited the consistency of findings, alterations in DWI metrics were most commonly reported in the corpus callosum, corona radiata, internal capsule, and long association pathways. Many acute/subacute pediatric studies reported higher FA and lower ADC or MD in various regions. In contrast, acute/subacute adult studies most commonly indicate lower FA within the context of higher MD and RD. In the chronic phase of recovery, FA may remain low, possibly indicating overall demyelination or Wallerian degeneration over time. Longitudinal studies, though limited, generally indicate at least a partial normalization of DWI metrics over time, which is often associated with functional improvement. We conclude that DWI is able to detect structural mTBI-related abnormalities that may persist over time, although future DWI research will benefit from larger samples, improved data analysis methods, standardized reporting, and increasing transparency.

有证据表明，弥散加权成像 (DWI) 能够检测到轻度创伤性脑损伤 (mTBI) 后的组织改变，而传统神经成像可能无法观察到这些改变；然而，研究之间的结果往往不一致。该系统评价评估了有和没有 mTBI 病史的人在 DWI 指标方面的差异模式。使用相关索引术语对 2020 年 5 月 14 日之前发表的文章进行了 PubMed 文献搜索。结果仅限于在 mTBI 中使用 DWI 的人体研究。如果文章不是完整的，不包含原始数据，如果它们是案例研究，与军人有关，伤害严重程度分类不充分，或没有报告受伤后间隔，则文章被排除在外。四个亚组的调查结果是独立报告的：包括急性/亚急性儿童 mTBI、急性/亚急性成人 mTBI、慢性成人 mTBI 和运动相关脑震荡，以及所有使用的 DWI 采集和分析方法。报告了研究之间的发现模式，以及文献现状的优缺点。尽管样本特征和研究方法的异质性限制了研究结果的一致性，但 DWI 指标的改变最常见于胼胝体、放射冠、内囊和长关联通路。许多急性/亚急性儿科研究报告了不同地区较高的 FA 和较低的 ADC 或 MD。相比之下，急性/亚急性成人研究最常表明在较高的 MD 和 RD 的情况下较低的 FA。在恢复的慢性阶段，FA 可能仍然很低，可能表明随着时间的推移整体脱髓鞘或华勒变性。纵向研究虽然有限，但通常表明 DWI 指标随时间至少部分正常化，这通常与功能改善有关。我们得出的结论是，DWI 能够检测出可能持续存在的结构性 mTBI 相关异常，尽管未来的 DWI 研究将受益于更大的样本、改进的数据分析方法、标准化的报告和增加的透明度。