Bilateral superior pharyngeal artery from common carotid artery and ascending pharyngeal artery from internal carotid artery
Presentation
Dysarthria, left hemiparesis, facialis. Incidental findings on CTA.
Patient Data
Infarct in the right corona radiata (not shown).
On both sides, the superior thyroid artery arises (right, left) from the common carotid artery proximal to the carotid bifurcation and the ascending pharyngeal artery arises from the internal carotid artery (ICA), immediately distal to the bifurcation.
Hypoplastic right vertebral artery (RVA) with PICA termination (i.e., the intracranial segment [V4] gives off the PICA and does not extend beyond it to the basilar artery).
Of note, the extracranial carotid arteries are kinked in a young patient.
Coronal oblique MIP reformation of the carotids shows that on both sides, the superior thyroid artery (orange arrowheads) and ascending pharyngeal artery (blue arrowheads) arises from the internal carotid artery.
Axial MIP at the level of the foramen magnum shows the PICA termination of the intracranial right vertebral artery - the segment between the origin of the PICA and the basilar artery is missing.
Case Discussion
The superior thyroid artery is the first branch to arise from the external carotid artery (ECA). The ascending pharyngeal artery is usually the second branch from the ECA or it may branch off the occipital artery.
In the case presented here, there are two rare coexisting variants: both superior thyroid arteries arise from the common carotid arteries proximal to the carotid bifurcation and both ascending pharyngeal arteries arise from the internal carotid arteries distal to the bifurcation.
PICA termination of a hypoplastic vertebral artery, also present in this case, is another arterial variant.
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