The Correlation of Intracranial Artery Calcification and Outcomes of Mechanical Thrombectomy

Inclusion Criteria: * Male or non-pregnant women with acute stroke symptoms aged over 18 years. * Occlusion of the intracranial internal carotid artery, the middle cerebral artery, the anterior cerebral artery, the posterior cerebral artery, basilar artery and intracranial vertebral artery confirmed by CT, MR angiography, or digital subtraction angiography. * No absolute contraindication to iodinated contrast media. * Planned treatment with EVT by clinical care team. * Informed consent obtained from patients or their legal representatives. * Willing to be followed up as required by the clinical study protocol. Exclusion Criteria: * Acute ischemic stroke occurs over 24 hours of time last known well. * Neurologic deficits caused by diagnoses other than ischemic stroke, such as intracerebral hemorrhage, subarachnoid hemorrhage, or intracranial tumors. * With other underlying factors leading to IAC, such as hyperthyroidism, end-stage renal disease, long-term oral intake of vitamin K antagonist(Warfarin), chronic vitamin D deficiency or overdose, persistent hypomagnesemia, persistent hypercalcemia, persistent hyperphosphatemia and high oral calcium intake. * Lack of non-contract CT images on admission and significant artifacts in CT images preventing IAC measurement. * Severe renal insufficiency (estimated glomerular filtration rate \< 30ml/min or serum creatinine \> 220μmol/L (2.5mg/dl)). * Previous cerebrovascular intervention treatment or craniotomy.