1, cerebrovascular malformations / congenital developmental anomalies. MoyaMoya disease, cerebrovascular arteriovenous malformations / fistulas, entrapment aneurysms; congenital developmental anomalies: abnormal fibromuscular development of the vessel wall, carotid artery kinking, coiling, dysplasia and sinuous dilatation; neoplastic vascular endotheliopathy, etc. 2. Infection. Leptospiral vaso-occlusive cerebral infarction; granulomatous arteritis: tuberculosis, syphilis; infectious arteritis: herpes simplex virus, mycoplasma pneumonia, malaria, rickettsial disease, brucellosis, mycosis, AIDS, etc.; parasitic infection: cerebral cysticerci, pulmonary schistosomes, etc. 3.Automorphic reactions. Polyarteritis major; systemic arteritis: Wegener’s syndrome, rheumatic arteritis, nodular arteritis; ulcerative colitis; collagen disease, etc. 4. Cardiogenic emboli. Rare valvular lesions: mitral valve prolapse, annular calcification; infective endocarditis, cachexia, aseptic endocarditis; rheumatic heart disease, atrial fibrillation; sick sinus syndrome; atrial mucinous tumor, cardiac rhabdomyoma, cardiac capillary fibroelastic histoma; dilated cardiomyopathy; post cardiac surgery or catheterization; atrial septum, ventricular septal defect with regurgitation, appendage thrombosis. 5. Hypercoagulability/appearance of abnormal components. Protein C and S deficiency; hyperfibrinogenemia, antithrombin III deficiency, thrombocytosis, platelet hyperaggregation, DIC, sickle cell anemia, β-thalassemia, PNH (release of procoagulant substances and complement after rupture of red blood cells), prokinetic peptide-releasing enzyme deficiency, alcoholism; presence of abnormal components in the blood: antiphospholipid antibodies, plasma cell disease or bone marrow Immunoglobulins secreted in proliferative syndromes, etc.; snake bites. 6, genetic mutations. CADASIL: autosomal dominant cerebral arteriopathy with subcortical infarction and white matter encephalopathy; MELAS: mitochondrial encephalomyopathy with lactic acidosis and stroke attack; Fabry disease: diffuse somatic angiokeratoma, familial phospholipid storage disease which affects blood vessels; Marfan syndrome: spider’s finger, ophthalmopathy, cardiovascular disease such as atrial aneurysm. 7, vascular injury. Cranial trauma, surgery, insertion of catheters, puncture, etc. 8, Other. Migraine; oral contraceptives; Sneddon syndrome; circumflex subluxation, osteosclerosis; venous thrombosis dislodgement, fat embolism, fibrocartilage embolism, air tethering, foreign body embolism, aneurysm embolism, embolism distal to saccular aneurysm, amniotic fluid embolism.