Brain arteries. Rotating view of a 3D magnetic resonance angiography (MRA) volume-rendered scan of the major intra-cranial arterial blood vessels (orange) of the human brain. This frontal view starts with the front of the brain at front, with the brain then rotated 360 degrees vertically backwards. MRA is a magnetic resonance imaging (MRI) technique that highlights blood vessels, usually by the use of injected contrast agents that make the blood vessels more visible on the MRI scans.