In-vivo imaging of a rare constellation of arterial variants: Aberrant subclavian artery, bicarotid trunk, and ectopic vertebral arteries

Abstract

We report in-vivo imaging of a constellation of arterial variants found incidentally on CT-angiography in a 23-year-old woman presenting with an ischaemic stroke. This extremely rare combination includes a common origin of both common carotid arteries, an abnormal origin of the right vertebral artery (VA) from the right common carotid artery and of the left VA from the aortic arch, associated with an aberrant right subclavian artery. This constellation, previously described in a female cadaver, has not been reported in-vivo. Awareness of this configuration is crucial for radiological diagnosis and when performing angiography and endovascular or surgical procedures in thorax, head and neck, to avoid complications.

Keywords: Aberrant right subclavian artery; bicarotid trunk; cerebral arteries variants; ectopic vertebral artery.

Figure 1.

CT angiogram (CTA) was performed using 320-slice Aquilion one system (Canon medical systems). 1: truncus bicaroticus; 2: right common carotid artery; 3: right vertebral artery; 4: left common carotid artery; 5: left vertebral artery; 6: aberrant right subclavian artery (ARSA). A - 3D CTA reconstructions (Volume rendering, VR) clearly shows: a common origin for both common carotid arteries (CCA), that is, a truncus bicaroticus (1), this truncus bicaroticus being the first main branch of the aortic arch and gives raise to the right CCA (2) and the left CCA (4), the right CCA giving rise to the right vertebral artery (VA) (3), which ascends and enters the right transverse foramen of C5 (white arrow); the left VA (5) which arises directly from the aortic arch between the common carotid trunk and the left SCA and enters the left transverse foramen of C5 (black arrow). The aberrant right subclavian artery (ARSA) (6) originates from the posterior portion of the aortic arch and then crosses the midline. An aberrant right subclavian artery (ARSA) originates from the posterior portion of the aortic arch and then crosses the midline. This ARSA, clinically silent and discovered incidentally, is also shown on coronal (B: 1: truncus bicaroticus; 2: right CCA; 3: right VA; 4: left CCA; 5: left VA, arising from the aortic arch, black arrow, 6; ARSA; 7: left subclavian artery) and axial (c) multiplanar reconstructions (MPR), the axial plane demonstrating its course behind the oesophagus (C, arrow).