What indicates that you are visualizing the internal carotid artery (ICA) in duplex US or MRI?

Visualizing the internal carotid artery (ICA) in duplex ultrasound or MRI is indicated by the characteristic absence of branches near its bifurcation. Unlike the external carotid artery (ECA), which has a number of branches that emerge near the carotid bifurcation, the ICA typically does not give off branches in this region. This anatomical distinction is crucial for accurate identification.

In imaging modalities like duplex ultrasound, recognizing that the ICA lacks the branching patterns observed in the ECA helps in differentiating between these two arteries. The internal carotid is responsible for supplying blood to the brain, while the external carotid supplies the face and neck, making their identification vital during vascular assessments.

Other aspects, such as differing colors or velocities between the ICA and ECA, do not provide definitive visual or Doppler criteria. Instead, the presence of branches serves as a clear anatomical cue for distinguishing these significant vessels.