烟雾病是儿童缺血性脑卒中的重要病因，研究显示儿童病人认知功能障碍的风险高于成人。认知功能障碍是烟雾病继发病还是烟雾病发展过程中直接导致尚不清楚。文献报道和我们前期研究显示脑血流低灌注和成人患者认知功能障碍有关。考虑年龄因素和放射暴露对生长发育的影响，目前有关低龄儿童烟雾病脑血流动力学研究偏少，其局部脑组织血流灌注异常和认知功能障碍的相关性尚不清楚。研究显示，动脉自旋标记（ASL）成像技术具有无创和无放射的优点，我们前期工作发现伪连续ASL在成人烟雾病脑灌注评估中具有很好匹配性。本课题采用伪连续ASL成像技术，研究低龄儿童烟雾病的脑血管分布和脑血流灌注特点，并在此基础上开展个体化血管重建术，通过手术前后对认知功能的测评，探讨低龄儿童烟雾病局部脑血流灌注异常和认知功能障碍的相关性。研究实施不仅为低龄儿童烟雾病的术前评估提供一种安全可靠的方法，同时为探寻烟雾病认知功能障碍病因提供早期客观依据。

Moyamoya disease(MMD) is an important causes of cerebral ischemic stroke in children.Recent studies have showed that the risk of cognitive impairment in children with MMD was higher than the risk in adults patients. One point of controversy is whether the diminished intelligence is due to a secondary condition accompanying MMD or is directly a product of the disease Process. According to reports in the literature and our previous study, cerebral hypoperfusion was related to the cognitive dysfunction in adults patients with MMD. At present, there are very few studies about the characteristics of cerebral hemodynamics in younger children with MMD due to the small age and consideration of effect of the radiation exposure.The relativity between the abnormal perfusion in regional brain and cognitive impairment in younger children remains unclear. Arterial spin-labeling(ASL) is a well-established method for the assessment of cerebral vascular disease. It does not require the injection of an exogenous contrast agent and have no radiation exposure. Our previous study found that there is a correlation between perfusion data from ASL and CT perfusion imaging in adult patients with MMD. In this study，pseudo-continuous ASL 3.0T MR protocol was applied on younger children with MMD. We investigate characteristic of distribution of cerebral vascular arteries and cerebra perfusion and study the relativity between abnormal cerebral perfusion and cognitive dysfunction . This research work is expected to provide a safe and noninvasive technique in evaluation of cerebral perfusion and nerve function in children with MMD. This method will provide a reliable objective evidence about the mechanisms of cognitive dysfunction in MMD.