Anatomic variations of the carotid bifurcation affecting doppler scan interpretation

An anatomic variant for the position of the external carotid artery (ECA) at the carotid bifurcation was noted in 5.3 percent of patients studied by Doppler ultrasound and contrast angiography. The ECA is lateral to and posterior to the internal carotid artery (ICA) in these patients. Consideration of this important variant is mandatory for accurate ultrasound image correlation.