Lateralized internal carotid artery

The lateralized internal carotid artery is an anatomic variation of the course of the petrous segment of the internal carotid artery (ICA). It can be visualized on CT by its more posterolateral entrance to the skull base and protrusion into the anterior mesotympanum.

Clinical presentation

It may result in pulsatile tinnitus.

Radiographic features 

CT
  • in the axial plane, the genu of the vertical and horizontal segments of the petrous ICA is more lateral than the mid-portion of the basal turn of the cochlea
  • focal thinned or dehiscent carotid plate (lateral wall of the carotid canal)
  • the inferior tympanic canaliculus is not affected

Differential diagnosis