Aortic arch demonstrates anatomical variation with four vessels with the left vertebral artery originating from the arch.
Contrast filling defect is seen within the distal right common carotid just proximal to the carotid bulb and extending cranially with 50% luminal narrowing extending over a length of 20 mm. The right internal carotid demonstrates no contrast filling from C1-C6.
The left common carotid also demonstrates contrast filling defect from the carotid bulb extending caudally with no contrast seen in the internal left carotid from C1-C6.
The intracranial bilateral ICAs are non opacified with some reconstitution of contrast present within the right cavernous ICA and left supraclinoid ICA from the posterior circulation, hypoplastic left PCOM noted.
Right A1 segment demonstrates contrast filling defect corresponding to the hyperattenuating vessel noncontrast scan. Potential collateral filling of the A2 segment which is of reduced calibre and irregular relative to the left. No filling defects identified within the bilateral M1 and M2 segments.
Small linear filling defect within the origin of the basilar artery could represent small nonocclusive thrombus. Multifocal narrowing and irregularity of the right V1 segment with good opacification distally.
Mild calcified atheroma involving the bilateral carotid bulbs and ICAs.