Moyamoya disease is also known as spontaneousocclusionofthecircleofWillis (SOCW). It is characterized on cerebral angiography by bilateral stenosis or occlusion of the terminal segment of the internal carotid artery and by varying degrees of abnormal reticular vessels visible on the floor of the brain bilaterally. Sometimes some major cerebral arteries may not appear, such as the anterior cerebral artery, middle cerebral artery, and even the posterior cerebral artery. over the past 40 years, the international medical community has accumulated a lot of research results on smog disease, and under the current technical conditions, it is not difficult to diagnose smog disease. 1.Research history In 1955, Japanese scholars Shimizu and Takeuchi first reported the cerebral angiography of the disease, and in 1957, Takeuchi officially published an article reporting the disease, which was considered to be bilateral internal carotid artery dysplasia at that time. Subsequently, the same cases began to be reported, but all were reported as congenital anomalies or vascular tumors, and the angiograms of these cases appear to be smoldering today.In 1963, at the 22nd Japanese Society for Neurosurgery, Shimizu reported six different cases with cerebral angiographic manifestations, laying the foundation for the modern medical understanding of smoldering disease.Shimizu proposed that the abnormalities of the cerebral floor reticular vessels, which are neovascularization of the collateral circulation caused by acquired, chronic progressive stenosis of the terminal segment of the internal carotid arteries bilaterally, are the most fundamental clinical feature of smoker’s disease. The disease was first reported by Japanese scholars, and since then cases have been reported from all over the world and is no longer considered to be a disease specific to the Japanese nationality. In 1965, Weidner reported the first case in a female patient of Japanese descent in the United States. In the same year, Krayenbühl and Yasargil included the cerebral angiographic manifestations of the disease in Krayenbühl’s textbook. The disease then gradually began to be reported around the world, and scholars found that the disease was not limited to Japan. In 1965, Suzuki first named the disease Moyamoya disease, the Japanese word for “Moyamoya” used to describe phenomena such as breathing, smoky, blurred, or unclear. The abnormal vascular network at the base of the patient’s brain appears on the angiogram as “smoke”, and the long-term follow-up of the young patients revealed that the cerebral angiogram showed heavy smoke at the onset of the disease in early childhood, and then gradually thinned out, and finally the internal carotid artery and surrounding reticular vessels disappeared, which is similar to the appearance and disappearance of smoke. The disease is called smog disease [1]. Currently, the typical smog disease is defined as the narrowing or occlusion of blood vessels including the terminal segment of the bilateral internal carotid arteries, the beginning segment of the anterior cerebral artery, and the beginning segment of the middle cerebral artery, and the abnormal vascular network in the above-mentioned parts during the arterial phase of cerebral angiography. Scholars from various countries agree that the smoldering vessels are collateral circulation caused by chronic progressive stenosis of the terminal segments of the internal carotid arteries bilaterally, but the etiology is not clear. 2.Epidemiology, pathology and clinical manifestations