Heiss W D
Max Planck Institute for Neurological Research and Department of Neurology, University of Cologne, Germany.
Keio J Med. 2001 Dec;50(4):249-56. doi: 10.2302/kjm.50.249.
Active treatment of acute ischemic stroke can only be successful as long as tissue in the area of ischemic compromise is still viable. Therefore, the identification of the area of irreversible damage, and its distinction from the penumbral zone, i.e., tissue with impaired function but preserved morphology, may improve the estimation of the potential efficacy of various therapeutic strategies. This can be achieved by multi-tracer positron emission tomography (PET), perfusion-weighted and diffusion-weighted magnetic resonance imaging in experimental models. Neuroimaging modalities applied in patients with acute ischemic stroke cannot reliably identify penumbra tissue and detect irreversible damage in the first hours after stroke, when treatment must be initiated to have the potential for success: multitracer studies for the assessment of flow and irreversible metabolic damage usually are limited in the clinical setting, and arterial blood sampling necessary for quantitative determinations is prohibited under certain circumstances, e.g., when thrombolysis is planned. The range of the penumbra can be assessed by combining determinations of flow and benzodiazepine receptor binding by PET of H2(15)O and 11C-flumazenil (FMZ) and relating flow values and FMZ binding to the final state of the tissue. By this approach, cumulative probability curves can be computed to predict eventual infarction or non-infarction and to define the penumbral range. The computed values are in good agreement with results from other studies proving the validity of the concept of the penumbra which was also demonstrated in several therapeutic studies in which thrombolytic treatment reversed critical ischemia and decreased the volume of the final infarcts. Such neuroimaging findings might serve as surrogate targets in the selection of other therapeutic strategies for large clinical trials.
急性缺血性卒中的积极治疗只有在缺血性损伤区域的组织仍存活时才可能成功。因此，识别不可逆损伤区域并将其与半暗带区分开来，即功能受损但形态保留的组织，可能会改善对各种治疗策略潜在疗效的评估。这可以通过多示踪正电子发射断层扫描（PET）、灌注加权和扩散加权磁共振成像在实验模型中实现。应用于急性缺血性卒中患者的神经影像学方法在卒中后的最初几个小时内无法可靠地识别半暗带组织并检测不可逆损伤，而此时必须启动治疗才有成功的可能：用于评估血流和不可逆代谢损伤的多示踪研究在临床环境中通常受到限制，并且在某些情况下，例如计划进行溶栓治疗时，定量测定所需的动脉血采样是被禁止的。半暗带的范围可以通过结合用H2(15)O和11C-氟马西尼（FMZ）的PET测定血流和苯二氮䓬受体结合，并将血流值和FMZ结合与组织的最终状态相关联来评估。通过这种方法，可以计算累积概率曲线以预测最终梗死或非梗死情况并确定半暗带范围。计算值与其他研究结果高度一致，证明了半暗带概念的有效性，这在一些治疗研究中也得到了证实，其中溶栓治疗逆转了严重缺血并减少了最终梗死灶的体积。这些神经影像学发现可能作为大型临床试验中选择其他治疗策略的替代靶点。
