ABSTRACT
Once the CCA is cannulated, it is important to clearly differentiate the ICA from the external carotid artery (ECA). The most important difference between the two is that the ICA has no branches in the extracranial portion, while the ECA-smaller in caliber-has extensive early branching. Subsequently, baseline intracranial imaging of the carotid artery needs to be performed to assess the presence of collaterals, as described in chapter 26, and have a baseline angiographic status.
