Dahl Juho, Tenovuo Olli, Posti Jussi P, Hirvonen Jussi, Katila Ari J, Frantzén Janek, Maanpää Henna-Riikka, Takala Riikka, Löyttyniemi Eliisa, Tallus Jussi, Newcombe Virginia, Menon David K, Hutchinson Peter J, Mohammadian Mehrbod
Turku Brain Injury Center, Turku University Hospital, University of Turku, Turku, Finland.
Neurocenter, Department of Neurosurgery, Turku Brain Injury Center, Turku University Hospital, University of Turku, Turku, Finland.
Front Neurol. 2022 May 31;13:888815. doi: 10.3389/fneur.2022.888815. eCollection 2022.
Diffuse axonal injury (DAI) is a common neuropathological manifestation of traumatic brain injury (TBI), presenting as traumatic alterations in the cerebral white matter (WM) microstructure and often leading to long-term neurocognitive impairment. These WM alterations can be assessed using diffusion tensor imaging (DTI). Cerebral microbleeds (CMBs) are a common finding on head imaging in TBI and are often considered a visible sign of DAI, although they represent diffuse vascular injury. It is poorly known how they associate with long-term white matter integrity. This study included 20 patients with TBI and CMBs, 34 patients with TBI without CMBs, and 11 controls with orthopedic injuries. DTI was used to assess microstructural WM alterations. CMBs were detected using susceptibility-weighted imaging (SWI) and graded according to their location in the WM and total lesion load was counted. Patients underwent SWI within 2 months after injury. DTI and clinical outcome assessment were performed at an average of eight months after injury. Outcome was assessed using the extended Glasgow Outcome Scale (GOSe). The Glasgow Coma Scale (GCS) and length of post-traumatic amnesia (PTA) were used to assess clinical severity of the injury. We found that CMB grading and total lesion load were negatively associated with fractional anisotropy (FA) and positively associated with mean diffusivity (MD). Patients with TBI and CMBs had decreased FA and increased MD compared with patients with TBI without CMBs. CMBs were also associated with worse clinical outcome. When adjusting for the clinical severity of the injury, none of the mentioned associations were found. Thus, the difference in FA and MD is explained by patients with TBI and CMBs having more severe injuries. Our results suggest that CMBs are not associated with greater WM alterations when adjusting for the clinical severity of TBI. Thus, CMBs and WM alterations may not be strongly associated pathologies in TBI.
弥漫性轴索损伤（DAI）是创伤性脑损伤（TBI）常见的神经病理学表现，表现为脑白质（WM）微观结构的创伤性改变，并常导致长期神经认知障碍。这些WM改变可通过扩散张量成像（DTI）进行评估。脑微出血（CMB）是TBI患者头部影像学检查中的常见发现，通常被认为是DAI的一个可见征象，尽管它们代表的是弥漫性血管损伤。目前对它们与长期白质完整性之间的关联知之甚少。本研究纳入了20例患有TBI和CMB的患者、34例患有TBI但无CMB的患者以及11例患有骨科损伤的对照者。使用DTI评估微观结构WM改变。使用磁敏感加权成像（SWI）检测CMB，并根据其在WM中的位置进行分级，计算总病变负荷。患者在受伤后2个月内接受SWI检查。DTI和临床结局评估平均在受伤后8个月进行。使用扩展格拉斯哥预后量表（GOSe）评估结局。使用格拉斯哥昏迷量表（GCS）和创伤后遗忘症（PTA）的时长来评估损伤的临床严重程度。我们发现CMB分级和总病变负荷与分数各向异性（FA）呈负相关，与平均扩散率（MD）呈正相关。与无CMB的TBI患者相比，患有TBI和CMB的患者FA降低而MD升高。CMB也与更差的临床结局相关。在对损伤的临床严重程度进行校正后，未发现上述任何关联。因此，FA和MD的差异是由患有TBI和CMB的患者损伤更严重所解释的。我们的结果表明，在校正TBI的临床严重程度后，CMB与更大的WM改变无关。因此，CMB和WM改变在TBI中可能不是强相关的病理学表现。
