Department of Radiology, Geneva University Hospital, 24 rue Micheli-du-Crest, Geneva, Switzerland.
Eur Neurol. 2010;64(5):286-96. doi: 10.1159/000321162. Epub 2010 Oct 27.
In acute stroke it is no longer sufficient to detect simply ischemia, but also to try to evaluate reperfusion/recanalization status and predict eventual hemorrhagic transformation. Arterial spin labeling (ASL) perfusion may have advantages over contrast-enhanced perfusion-weighted imaging (cePWI), and susceptibility weighted imaging (SWI) has an intrinsic sensitivity to paramagnetic effects in addition to its ability to detect small areas of bleeding and hemorrhage. We want to determine here if their combined use in acute stroke and stroke follow-up at 3T could bring new insight into the diagnosis and prognosis of stroke leading to eventual improved patient management.
We prospectively examined 41 patients admitted for acute stroke (NIHSS >1). Early imaging was performed between 1 h and 2 weeks. The imaging protocol included ASL, cePWI, SWI, T2 and diffusion tensor imaging (DTI), in addition to standard stroke protocol.
We saw four kinds of imaging patterns based on ASL and SWI: patients with either hypoperfusion and hyperperfusion on ASL with or without changes on SWI. Hyperperfusion was observed on ASL in 12/41 cases, with hyperperfusion status that was not evident on conventional cePWI images. Signs of hemorrhage or blood-brain barrier breakdown were visible on SWI in 15/41 cases, not always resulting in poor outcome (2/15 were scored mRS = 0-6). Early SWI changes, together with hypoperfusion, were associated with the occurrence of hemorrhage. Hyperperfusion on ASL, even when associated with hemorrhage detected on SWI, resulted in good outcome. Hyperperfusion predicted a better outcome than hypoperfusion (p = 0.0148).
ASL is able to detect acute-stage hyperperfusion corresponding to luxury perfusion previously reported by PET studies. The presence of hyperperfusion on ASL-type perfusion seems indicative of reperfusion/collateral flow that is protective of hemorrhagic transformation and a marker of favorable tissue outcome. The combination of hypoperfusion and changes on SWI seems on the other hand to predict hemorrhage and/or poor outcome.
在急性脑卒中中，单纯检测缺血已不再足够，还需要评估再灌注/再通状态，并预测最终的出血转化。动脉自旋标记（ASL）灌注相对于对比增强灌注加权成像（cePWI）可能具有优势，而磁敏感加权成像（SWI）除了能够检测到小面积出血和出血外，还具有对顺磁性效应的固有敏感性。我们想在这里确定，在急性脑卒中患者中，联合使用这两种技术进行 3T 扫描，是否能为脑卒中的诊断和预后提供新的见解，从而最终改善患者的管理。
我们前瞻性地检查了 41 名因急性脑卒中（NIHSS＞1）入院的患者。早期影像学检查在发病后 1 小时至 2 周内进行。成像方案包括 ASL、cePWI、SWI、T2 和弥散张量成像（DTI），此外还有标准的脑卒中成像方案。
根据 ASL 和 SWI，我们观察到了四种影像学模式：ASL 灌注不足和灌注过度，SWI 有或无变化。ASL 灌注过度在 41 例患者中的 12 例中可见，而在常规 cePWI 图像上并不明显。SWI 在 41 例患者中的 15 例中可见出血或血脑屏障破坏的迹象，并不总是导致不良预后（2/15 患者 mRS 评分为 0-6）。早期 SWI 改变，加上灌注不足，与出血的发生有关。ASL 灌注过度，即使与 SWI 检测到的出血并存，也会导致良好的预后。灌注过度比灌注不足预测更好的预后（p=0.0148）。
ASL 能够检测到与以前 PET 研究报道的奢侈灌注相对应的急性期灌注过度。ASL 型灌注中出现灌注过度似乎表明再灌注/侧支血流的存在，这种再灌注/侧支血流对出血转化具有保护作用，是组织预后良好的标志物。另一方面，灌注不足和 SWI 变化的组合似乎预示着出血和/或不良预后。
