The goal of Shanghai stroke service system is to promote and facilitate high quality standardized stroke care in Shanghai area. The 11 hospitals involved are committed to provide the best stroke care to their patients. This quality goal consists of two parts: the acute phase of stroke care and the subsequent care during the hospitalization. To accomplish this goal, each hospital has organized a multidisciplinary stroke team that will address day-to-day stroke care. Each hospital provides prioritized neuroimaging service to patients with acute stroke 24hr per day, 7days per week. A stroke neurologist is on site 24hr per day, 7 days per week in each hospital. This team will follow the guidelines to carry out standardized secondary stroke prevention once the patient has been admitted.