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
- aberrant internal carotid artery: usually courses across the middle ear along the cochlear promontory and shows an enlarged inferior tympanic canaliculus
