Arteritis. Coloured coronal (frontal) magnetic resonance angiography (MRA) scan of diseased arteries (white/blue) in the lower abdomen, groin and upper legs of a patient with arteritis. This is a disease where the arteries become inflamed. Scarring and fat deposition have caused multiple sites of stenosis, narrowing of the blood vessels. The last part of the main body artery, the aorta, runs from top centre to upper centre (just above the groin), dividing into the iliac arteries that become the femoral arteries of the upper legs. MRA is a magnetic resonance imaging (MRI) technique that highlights blood vessels without the need for X-rays or the injection of a radio-opaque dye.