Zhang X, et al. - The association between baseline collaterals and the onset-to-imaging time (OIT) was explored. In addition, the researchers aimed to investigate the correlation between pre-treatment collateral status and clinical outcome among different subtypes. In CE, sustained good leptomeningeal collaterals could predict the good outcome but not in LAA patients, based on 4D-CTA. Furthermore, the extent of collaterals was correlated with OIT in CE, that indicated prompt reperfusion therapy in this group of patients.