Why we use imaging
In the UK, MRA is the investigation of choice and with advances in scanner technology the sensitivity of MRA is approaching that of the gold standard: cerebral angiography.
Both CTA and MRA will usually reveal a decrease in the diameter of the affected vessel and, possibly, signs of an intramural haematoma.
It is less common to see an intimal flap.
Although still the gold standard investigation, cerebral angiography is invasive and not routinely performed in the UK.
It is probably best reserved for patients in whom there is a high clinical suspicion, but a normal MRA.