Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Hum Brain Mapp. 2024 Jan;45(1):e26556. doi: 10.1002/hbm.26556. Epub 2023 Dec 29.
Magnetic resonance imaging (MRI) diffusion studies have shown chronic microstructural tissue abnormalities in athletes with history of concussion, but with inconsistent findings. Concussions with post-traumatic amnesia (PTA) and/or loss of consciousness (LOC) have been connected to greater physiological injury. The novel mean apparent propagator (MAP) MRI is expected to be more sensitive to such tissue injury than the conventional diffusion tensor imaging. This study examined effects of prior concussion severity on microstructure with MAP-MRI. Collegiate-aged athletes (N = 111, 38 females; ≥6 months since most recent concussion, if present) completed semistructured interviews to determine the presence of prior concussion and associated injury characteristics, including PTA and LOC. MAP-MRI metrics (mean non-Gaussian diffusion [NG Mean], return-to-origin probability [RTOP], and mean square displacement [MSD]) were calculated from multi-shell diffusion data, then evaluated for associations with concussion severity through group comparisons in a primary model (athletes with/without prior concussion) and two secondary models (athletes with/without prior concussion with PTA and/or LOC, and athletes with/without prior concussion with LOC only). Bayesian multilevel modeling estimated models in regions of interest (ROI) in white matter and subcortical gray matter, separately. In gray matter, the primary model showed decreased NG Mean and RTOP in the bilateral pallidum and decreased NG Mean in the left putamen with prior concussion. In white matter, lower NG Mean with prior concussion was present in all ROI across all models and was further decreased with LOC. However, only prior concussion with LOC was associated with decreased RTOP and increased MSD across ROI. Exploratory analyses conducted separately in male and female athletes indicate associations in the primary model may differ by sex. Results suggest microstructural measures in gray matter are associated with a general history of concussion, while a severity-dependent association of prior concussion may exist in white matter.
磁共振成像（MRI）扩散研究表明，有脑震荡病史的运动员存在慢性微观结构组织异常，但研究结果不一致。有创伤后遗忘症（PTA）和/或意识丧失（LOC）的脑震荡与更大的生理损伤有关。新型平均表观扩散系数（MAP）MRI 有望比传统的扩散张量成像更能检测到这种组织损伤。本研究通过 MAP-MRI 检查了先前脑震荡严重程度对微观结构的影响。大学生年龄的运动员（N=111，38 名女性；如果存在，距最近一次脑震荡至少 6 个月）完成了半结构化访谈，以确定是否存在先前的脑震荡以及与损伤相关的特征，包括 PTA 和 LOC。从多壳扩散数据中计算出 MAP-MRI 指标（非高斯扩散的平均[NG Mean]、返回原点的概率[RTOP]和均方位移[MSD]），然后通过在主要模型（有/无先前脑震荡的运动员）和两个次要模型（有/无 PTA 和/或 LOC 的先前脑震荡的运动员，以及仅有 LOC 的先前脑震荡的运动员）中进行组比较，评估与脑震荡严重程度的关联。贝叶斯多层次模型分别在白质和皮质下灰质的感兴趣区域（ROI）中估计模型。在灰质中，主要模型显示双侧苍白球的 NG Mean 和 RTOP 降低，左侧壳核的 NG Mean 降低，有先前脑震荡。在白质中，所有模型的所有 ROI 都存在先前脑震荡的 NG Mean 降低，而 LOC 则进一步降低。然而，只有 LOC 与先前脑震荡相关的 ROI 与 RTOP 降低和 MSD 增加相关。在男性和女性运动员中分别进行的探索性分析表明，主要模型中的关联可能因性别而异。结果表明，灰质中的微观结构测量与一般脑震荡史有关，而白质中可能存在与先前脑震荡严重程度相关的关联。
