1.What is a brain aneurysm? A: Aneurysm is not a tumor, but a cystic bulge formed by the local thinning of the vessel wall, just like the local bulge of an old bicycle inner tube after inflation. As the aneurysm wall becomes thinner and thinner, it eventually ruptures and leads to cerebral hemorrhage —- subarachnoid hemorrhage. 2.How does a brain aneurysm form? A: It is not very clear, but it is known to be related to the following factors: traumatic brain injury, cerebral arteriosclerosis, congenital abnormal vascular development, blood flow shock, infection, etc. 3.What are the conditions that can result from ruptured aneurysm and bleeding? A: Most of the patients’ first symptoms are sudden and severe headache, which is described as “the most severe headache in life”, and can lead to hemiplegia, aphasia, unconsciousness, coma or even death if the bleeding is large. The mortality rate of the first rupture of intracranial aneurysm is about 20%, and 7% of the patients die before they reach the hospital; if the surviving patients are not treated in time, they will bleed again or even repeatedly, and the mortality rate of re-bleeding is 67%. Some patients with intracranial aneurysms are accompanied by arteriovenous nerve palsy, especially those without headache symptoms and with droopy eyelids as the first symptom, which is easily misdiagnosed and patients often present with ophthalmologic disease. The differential diagnosis is required for myasthenia gravis ptosis, diabetic ptosis, brainstem lesion ptosis, and peripheral nerve ptosis. The majority of eyelid ptosis due to unruptured intracranial aneurysms is unilateral and no abnormalities are seen on CT and MRI, but cerebral angiography will clarify the diagnosis. 4.How can intracranial aneurysms be detected in time to avoid rupture leading to death? A: Unless the intracranial aneurysm is very large, the usual head CT and MRI cannot see the aneurysm, only special CT angiography (CTA) or magnetic resonance angiography (MRA) can better detect the aneurysm, but the most authoritative means to diagnose the aneurysm is whole brain angiography (DSA). 5.How to treat intracranial aneurysm? A: Unruptured aneurysms <3mm in diameter can be observed regularly, but those with risk factors (hypertension, family history of aneurysm, irregular aneurysm, etc.) and ruptured aneurysms need timely treatment. Method 1: Open aneurysm clamping, which requires incision of the scalp and lifting of the skull, picking up the brain tissue, revealing the aneurysm, and clamping the aneurysm with a specially designed titanium aneurysm clip. Method 2: Endovascular (interventional) embolization, in which an incision of about 2 mm is made at the root of the thigh, the femoral artery is punctured, a microcatheter is placed, and the intracranial vessels are entered along the connected vessels of the whole body, and finally the aneurysm cavity is closed by filling the aneurysm cavity with a special platinum microspring coil through the microcatheter. 6.What are the things that aneurysm patients usually pay attention to? A: (1) Bed rest; (2) Avoid strenuous exercise; (3) Relieve patients' tension and stabilize blood pressure; (4) Prevent and control constipation.