MR angiography.

The primary use of angiography in the neck, either conventional catheter angiography or non-invasive techniques (MR angiography, CT angiography and ultrasound), is for the evaluation of the presence and severity of carotid stenosis. Other conditions such as vertebral artery stenosis, carotid and vertebral artery dissection and fibromuscular dysplasia are much less common but easily detectable with conventional angiography and are becoming increasingly reliably evaluated by non-invasive imaging. Intracranially, the value of MR angiography is less clear cut. It is certainly of use presurgery to look for vessel occlusion and encasement of vessels by tumour. It is also useful in excluding venous thrombosis as a cause of stroke. MR angiography for the detection and screening of intracranial aneurysms is less clear cut and, at present, it is the author's belief that MR angiography cannot replace conventional catheter angiography. Straight-forward spin echo imaging is the most accurate way of detecting arteriovenous malformations (AVMs) with magnetic resonance.