Description 

The supraclinoid (carotid-ophthalmic) segment of the internal carotid artery (ICA) under the Bouthillier classification is defined as the segment between the ophthalmic and posterior-communicating arteries.1 We describe an unusual congenital anomaly of the supraclinoid internal carotid artery characterised by a large fenestration of its carotid-ophthalmic segment, associated with multiple aneurysms.

A 60-year-old female patient underwent investigation for persistent headaches and was found to have what appeared to be irregular fusiform dilatation of the intracranial right internal carotid artery on 1.5 T magnetic resonance angiography (MRA) time-of-flight imaging. Cerebral digital subtraction angiography (DSA) performed to further characterise this abnormality demonstrated two discrete aneurysms, one measuring 5 mm and the other 2 mm, arising from the posterior limb of a supraclinoid ICA fenestration (figure 1A).