MME TV Spot

This week Dr Shepherd reviews the basics of carotid imaging. A common issue for new practitioners of carotid imaging is determining the internal carotid artery from the external carotid artery. A few key points to keep in mind is that the ICA and internal jugular vein run together, also the ICA usually sits more posterolateral and the ECA sits more anteromedial. Another big difference is the ECA has branches- however, sometimes the branches are not seen in the sagittal scanning plane, a transverse approach with color Doppler helps to identify them. The temporal tap, which is a common trick of sonographers, we do not find helpful. The reason we do not trust the temporal tap for identification of the ECA is because roughly one third of patients show oscillations in the ICA from a temporal artery tap. In a normal patient, the ICA should have a low resistive flow pattern while the ECA has a high resistive flow pattern. In a patient with severe disease, the flow pattern may be disturbed and not follow the “rules”. The take away from this quick portion of Dr Shepherd's complete carotid lecture, is to take all the general rules into consideration. The common location, flow pattern, and anatomy give us a road map but when there is a road block, alternate routes are found. See you next week!