Toulouse University Medical Center, Acute Stroke Unit, Toulouse Neuro Imaging Center, 1, place du Dr-Baylac, 31059 Toulouse, France.
Rev Neurol (Paris). 2017 Nov;173(9):584-589. doi: 10.1016/j.neurol.2017.09.002. Epub 2017 Oct 13.
The ischemic penumbra is a transient and potentially reversible condition. Therefore, infarct progression and its counterpart penumbral salvage are highly variable and result from the interaction of 3 major factors: collateral flow, revascularization delay and success. Multimodal brain imaging now offers in clinical practice an exhaustive characterization of the acute ischemic injury: vessel site occlusion, infarction/critical hypoperfusion volume, and collateral flow. From 1995 to 2015, IV alteplase administered within 4.5hours after the onset of acute BI diagnosed by the absence of hemorrhage on a non-contrast head CT scan has been the only approved revascularization treatment. Over the past 2years, 6 randomized trials have confirmed the benefit of a thrombectomy performed within 6-8 hours after the onset of an acute anterior BI downstream of an ICA/M1 occlusion. The recommended imaging modality for such patients remains a NCCT to exclude an hemorrhage and a CTA to confirm the proximal vessel occlusion. As a consequence, in the absence of collateral or penumbral imaging, studies and meta-analyses, have emphasized the importance of treatment delay on the outcome of patient after a revascularisation treatment (tPA/thrombectomy). These findings have supported the development of mobile stroke unit for tPA administration and the direct transfer of the patients eligible to thrombectomy to a comprehensive stroke center, bypassing primary stroke unit and sometimes conventional neuro imaging. In addition randomized controlled trial that did enroll patients based on the presence of a target mismatch on multimodal imaging demonstrated a higher benefit of revascularisation treatment by comparison with those who did not.This year the results of the randomized trial, Diffusion-weighted Imaging or Computerized Tomography Perfusion Assessment with Clinical Mismatch in the Triage of Wake-up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN)demonstrated for the first time that revascularization treatment for BI complicating an ICA or a proximal MCA M1 was still beneficial from 6 to 24hours after onset among patient who did have per their clinical exam and the multimodal brain imaging have a persistent penumbra. With this as a background we will discuss the yield of imaging for the selection of patients for a revascularization therapy.
缺血半暗带是一种短暂的、潜在可逆转的状态。因此，梗死进展及其对应的半暗带挽救具有高度的可变性，这是由三个主要因素相互作用的结果：侧支循环、再通延迟和再通成功。多模态脑成像现在在临床实践中提供了对急性缺血性损伤的详尽描述：血管部位闭塞、梗死/临界低灌注体积和侧支循环。从 1995 年到 2015 年，在非对比头部 CT 扫描未显示出血的情况下，对急性 BI 进行诊断后 4.5 小时内给予 IV 阿替普酶是唯一批准的再通治疗方法。在过去的 2 年中，6 项随机试验证实了在前循环 ICA/M1 闭塞下游的急性前循环 BI 发病后 6-8 小时内进行血栓切除术的益处。对于此类患者，推荐的成像方式仍然是 NCCT 以排除出血，CTA 以确认近端血管闭塞。因此，在没有侧支或半暗带成像的情况下，研究和荟萃分析强调了治疗延迟对再通治疗后患者结局的重要性（tPA/血栓切除术）。这些发现支持了移动卒中单元用于 tPA 给药的发展，并将符合血栓切除术条件的患者直接转至综合性卒中中心，绕过初级卒中单元，有时还绕过常规神经影像学检查。此外，基于多模态成像上的目标不匹配，随机对照试验纳入了患者，结果表明与未进行多模态成像的患者相比，再通治疗的获益更高。今年，随机试验的结果，即弥散加权成像或计算机断层灌注评估与临床不匹配在神经介入治疗中对觉醒和迟发卒中的分类（DAWN）表明，在 ICA 或近端 MCA M1 合并 BI 的患者中，从发病后 6 至 24 小时内进行再通治疗仍然是有益的，这些患者根据他们的临床检查和多模态脑成像仍有持续的半暗带。在此背景下，我们将讨论影像学检查在选择接受再通治疗的患者方面的效果。
