Intracranial arteriovenous malformations are the most common type of cerebrovascular malformation and are located superficially or deeply in the brain. The malformed vessels are composed of arteries and veins, and some contain aneurysms and venous aneurysms. Cerebral arteriovenous malformations have both blood supplying arteries and draining veins and are of various sizes and shapes. Types of disease Intracranial and intraspinal vascular malformations are congenital abnormalities of the vascular development of the central nervous system and can be divided into five types: 1) arteriovenous malformations (AVM); 2) cavernous hemangiomas; 3) capillary dilation; 4) venous malformations; and 5) varicose veins. Among the above five types of vascular malformations, arteriovenous malformations are the most common, accounting for 62.7% of intracranial supratentorial vascular malformations. It accounts for 42.7% of the subcurtain vascular malformation. The intracranial arteriovenous malformation (AVM) is a mass of abnormal development of pathological cerebral vessels. Its size can grow with human development. The AVM is formed by one or several curved and dilated arteries supplying blood and draining veins, with a small diameter of less than 1 cm and a large diameter of up to 10 cm. The AVM contains brain tissue and its surrounding brain tissue is atrophied due to ischemia, with gliosis and sometimes with old hemorrhage. The arachnoid membrane on the surface of the malformed vessels is white and thick. The intracranial AVM can be located anywhere in the cerebral hemisphere, with a wedge shape and its tip pointing to the lateral ventricles. Clinical manifestations 1, hemorrhage: rupture of the malformed vessels can lead to intracerebral, intraventricular and subarachnoid hemorrhage, resulting in impaired consciousness, headache and vomiting. Symptoms such as headache and vomiting. However, the clinical symptoms of small hemorrhage are not obvious. Most of the bleeding occurs in the brain, and 1/3 of them cause subarachnoid hemorrhage, accounting for 9% of subarachnoid hemorrhage, second to intracranial aneurysm. It is reported that the first symptom of AVM is hemorrhage in 30% to 65% of cases. The age of onset of hemorrhage is 20-40 years. It is generally believed that single branch supply artery, small size, deep site. As well as posterior cranial fossa AVMs are prone to acute rupture and bleeding. The risk of AVM rupture increases during pregnancy in women. Recent studies have found that the annual bleeding rate of unruptured AVMs in all age groups is about 2%. The risk of AVM bleeding is higher in young patients than in older patients, and the rate of rebleeding and post-bleeding mortality are lower in AVMs than in intracranial aneurysms. This is due to the fact that the source of hemorrhage is mostly a vein of pathological circulation with lower pressure than cerebral arterial pressure. In addition, hemorrhage is less likely to occur in the basal pool, and cerebral vasospasm secondary to hemorrhage is rare. 2. convulsions: 21% to 67% of adults have convulsions as the first symptom, and more than half of them occur before 30 years of age, mostly in frontal and temporal AVMs. frontal AVMs mostly have convulsive grand mal seizures, with restricted seizures on top. convulsions in AVMs are related to cerebral ischemia, progressive gliosis around the lesion, and stimulation of the cerebral cortex by iron-containing heme after hemorrhage. 14% to 22% of AVMs with hemorrhage will have convulsions. Convulsions occur. Early convulsions can be controlled with medication, but eventually medication is ineffective and convulsions are difficult to control. Due to long-term intractable seizures, the lack of oxygen to the brain tissue is aggravated, resulting in the patient’s mental retardation. 3. Headache: Half of the AVM patients have a history of headache. Headache can be unilateral and localized, or full headache. Intermittent or migratory. Headache may be related to the dilatation of blood supply arteries, drainage veins and sinuses, and sometimes related to small amount of bleeding, hydrocephalus and increased intracranial pressure in AVM. 4. Neurological deficit: 4%-12% of AVM with unruptured hemorrhage are acute or progressive neurological deficits. Intracerebral hemorrhage can cause acute neurological deficits. Due to the role of AVM blood theft or combined with hydrocephalus. Patients have progressive neurological deficits, manifesting as motor, sensory, visual field and speech dysfunction. Individual patients may have cranial murmur or trigeminal neuralgia. 5.Children with large venous malformation of the brain: also known as large venous aneurysm of the brain, which can lead to heart failure and hydrocephalus.