Uchida Yuto, Kan Hirohito, Inoue Hiroyasu, Oomura Masahiro, Shibata Haruto, Kano Yuya, Kuno Tomoyuki, Usami Toshihiko, Takada Koji, Yamada Kentaro, Kudo Kohsuke, Matsukawa Noriyuki
Department of Neurology, Nagoya City University, Nagoya, Japan.
Department of Neurology, Toyokawa City Hospital, Aichi, Japan.
Front Neurol. 2022 Feb 11;13:752450. doi: 10.3389/fneur.2022.752450. eCollection 2022.
The oxygen extraction fraction (OEF) has been applied to identify ischemic penumbral tissue, but is difficult to use in an urgent care setting. This study aimed to investigate whether an OEF map generated via magnetic resonance quantitative susceptibility mapping (QSM) could help identify the ischemic penumbra in patients with acute ischemic stroke.
This prospective imaging study included 21 patients with large anterior circulation vessel occlusion who were admitted <24 h after stroke onset and 21 age-matched healthy controls. We identified the ischemic penumbra as the region with a Tmax of >6 s during dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI) and calculated the perfusion-core mismatch ratio between the ischemic penumbra and infarct core volumes. The OEF values were measured based on magnetic susceptibility differences between the venous structures and brain tissues using rapid QSM acquisition. Volumes with increased OEF values were compared to the ischemic penumbra volumes using an anatomical template.
Eleven patients had a perfusion-core mismatch ratio of ≥1.8, and reperfusion therapy was recommended. In these patients, the volumes with increased OEF values of >51.5%, which was defined using the anterior circulation territory OEF values from the 21 healthy controls, were positively correlated with the ischemic penumbra volumes ( = 0.636, 95% CI: 0.059 to 0.895, = 0.035) and inversely correlated with the 30-day change in the National Institutes of Health Stroke Scale scores ( = -0.624, 95% CI: -0.891 to -0.039, = 0.041).
Tissue volumes with increased OEF values could predict ischemic penumbra volumes based on DSC-MRI, highlighting the potential of the QSM-derived OEF map as a penumbra biomarker to guide treatment selection in patients with acute ischemic stroke.
氧摄取分数（OEF）已被用于识别缺血半暗带组织，但在紧急护理环境中难以应用。本研究旨在调查通过磁共振定量磁化率映射（QSM）生成的OEF图是否有助于识别急性缺血性卒中患者的缺血半暗带。
这项前瞻性影像学研究纳入了21例大脑前循环大血管闭塞且在卒中发作后<24小时入院的患者以及21例年龄匹配的健康对照者。我们将缺血半暗带定义为动态磁敏感对比磁共振成像（DSC-MRI）期间Tmax>6秒的区域，并计算缺血半暗带与梗死核心体积之间的灌注核心不匹配率。使用快速QSM采集基于静脉结构和脑组织之间的磁化率差异测量OEF值。使用解剖模板将OEF值增加的体积与缺血半暗带体积进行比较。
11例患者的灌注核心不匹配率≥1.8，建议进行再灌注治疗。在这些患者中，OEF值增加>51.5%的体积（使用21例健康对照者的大脑前循环区域OEF值定义）与缺血半暗带体积呈正相关（r = 0.636，95%CI：0.059至0.895，P = 0.035），与美国国立卫生研究院卒中量表评分的30天变化呈负相关（r = -0.624，95%CI：-0.891至-0.039，P = （此处原文有误，根据前文推测可能是0.041））。
OEF值增加的组织体积可基于DSC-MRI预测缺血半暗带体积，突出了QSM衍生的OEF图作为半暗带生物标志物在指导急性缺血性卒中患者治疗选择方面的潜力。
