灌注联合通透性影像优化识别缺血半暗带

To identify tissue at risk and benign oligemia correctly is a key step to make a right treatment decision in hyper acute phase of ischemic stroke. But many studies suggested that perfusion technique often exaggerated the volume of the tissue at risk. In previous study, we demonstrated that BBB disruption may reflect some profiles of the severity of tissue damage and suggested a hypothesis that benign oligemia may have mild BBB disruption and BBB permeability(BBBP) can be a possible surrogate to differentiate the benign oligemia, penumbra and infarct core. We will.collect the perfusion and permeability imaging from the patients with acute ischemic stroke, compare the differences among perfusion data, permeability data, and final infarct volume, and try to access if permeability imaging can be used to identify benign oligemia. We will build rhesus monkey acute ischemic stroke model with chronic unilateral carotid occlusion. Multimodal imaging data and pathology changing about BBBP will be accessed to verify our hypothesis and build thereasonable BBBP threshold. The purpose of our study is to build a imaging biomarker, which can distinguish benign oligemia from tissue at risk and help to make right treatment decision.

准确区分缺血半暗带、良性缺血组织及梗死核心对于急性脑梗死的超早期治疗有重大意义 ,但由于缺性缺血状态下缺血阈值存在差异,常规的灌注成像容易夸大缺血半暗带的体积,对 治疗决策产生影响。前期研究发现,脑组织缺血的严重程度与血脑屏障通透性(BBBP)的高低有 相关性,据此提出假设:与良性缺血组织相比,缺血半暗带的血脑屏障(BBB)受损较重;联合 灌注与通透性成像,量化评估BBBP 可用来区分缺血半暗带、良性缺血组织和梗死核心。拟建 立慢性缺血状态下急性脑梗死的恒河猴动物模型,采集不同时相点的多模态影像数据,通过观 察影像数据与病理改变之间的相关性,证实假设,建立BBBP阈值。收集急性脑梗死患者超早期 的灌注及通透性成像数据,通过与最终梗死体积比较,对BBBP的阈值进行验证和修正。尝试建 立一个基于灌注及通透性成像,能准确区分缺血半暗带的影像学标志,帮助急性脑梗死超早期 的治疗决策。

目的：Ktrans图是通透性影像中常用的参数，用于定量评估BBB开放程度，可从PCT的首过模型中获得。本研究拟观察Ktrans图是否可以区分不同缺血区域BBB的损伤程度；联合灌注影像是否可以优化评估急性缺血性脑卒中患者临床预后及最终梗死体积。建立大鼠模型，利用通透性影像评估慢性低灌注状态下脑组织BBBP的变化，与相应区域的NVU病理改变进行相关性分析。筛选能够准确评估NVU损伤的的通透性参数。..方法：收集发病9小时内，并且接受动脉溶栓和/或机械取栓的急性前循环脑梗死患者。从传统的PCT中获得的首过数据得到Ktrans图，根据不同的Ktrans阈值定义缺血组织。分别以90天后mRS和FIV（最终梗死体积）为终点事件，用多元逻辑回归分析和多元线性回归分析筛选相关因变量。将实验动物分成三组，即正常SD大鼠，正常SHR大鼠及慢性低灌注SHR大鼠（双侧颈总动脉结扎3个月）。用多模态MRI评估感兴趣区ROI的通透性。将影像与病理数据进行一致性检验，筛选通透性影像参数。..结果：多元逻辑回归分析提示Ktrans-PIV与mRS显著相关(P = 0.009; OR = 1.960; 95% CI: 1.811-2.191)；年龄(P = 0.027; OR = 1.243; 95% CI: 1.022-1.512)和治疗前NIHSS评分（P = 0.029; OR = 1.085; 95% CI: 1.020-1.154）也可预测mRS。多元线性回归分析提示Ktrans-PIV与FIV相关最好(F = 75.590, P < 0.0001)；其次为出血转化(F = 11.650, P = 0.001)。慢性低灌注SHR组：Ktrans和相应区域的血管分离指数一致性最强（P=0.0015, R=0.827, 95% CI: 0.466 - 0.952）；其次，Kep与相应区域的血管分离指数也有较好的相关性（P=0.0163, R=0.686, 95% CI: 0.167- 0.908）。..结论：慢性低灌注可诱导缺血预适应，因而在伴有颈动脉重度狭窄时，PCT-PIV与最终梗死体积的差异明显增大，而Ktrans-PIV并未受此影响，可以优化评估临床预后，更加准确地识别缺血半暗带。DCE-MRI中Ktrans和Kep两个参数与NVU病理变化有较好的一致性，可用于活体下NVU损伤的评估。