Brain MRA (blood vessel MRI, with and without contrast)

What it is

Unenhanced brain MRA works because moving blood looks different from stationary tissue. That trick is good enough for most screening questions about the arteries at the base of the brain, but it has a known weakness: where blood slows, swirls or changes direction sharply, the signal drops away and the vessel can appear narrowed or absent when it is neither. Injected contrast does not depend on motion at all — it fills the vessel and is imaged as it passes — so it does not fail in the same places.

This code covers acquiring both. The unenhanced series is not a warm-up; it is a reference. Comparing the two is how a radiologist tells a genuine narrowing from an artefact of slow flow, and how something that was bright before the injection is distinguished from something that only became bright because of it. That comparison is the reason the study costs more than either half alone.

Why it is done

• To characterize an aneurysm more precisely than an unenhanced study can, particularly its neck and the vessels coming off it
• To follow an aneurysm already treated with a coil or a stent, where metal distorts the unenhanced images
• To look at an arteriovenous malformation or fistula, where abnormal vessels and abnormally fast flow both defeat unenhanced technique
• To assess narrowing of arteries inside the skull when an unenhanced study was equivocal
• To investigate inflammation of vessel walls, where enhancement of the wall itself is the finding
• To map the blood supply of a tumor before surgery

What to expect

Metal screening is done first and covers implants, pacemakers, aneurysm clips, stimulators and metal fragments. An intravenous line is placed in the arm. The first set of images is acquired with nothing injected; then the contrast is given through the line while you stay in the scanner, and timing matters, so you may be asked to hold very still or hold a breath at a precise moment. Because two acquisitions are being made, the appointment is longer than a single-phase study — commonly around an hour, more if a brain MRI is booked into the same slot. Hearing protection is provided. Nothing limits your activity afterward.

Questions worth asking

• Confirm the order really is with-and-without rather than one or the other. Three separate codes exist for head MRA and the price gap between them is substantial.
• If a brain MRI is scheduled in the same appointment, that is an additional code and an additional charge even though you never leave the scanner.
• Ask whether the contrast agent is itemized separately from the scan.
• For surveillance of a treated aneurysm, ask whether CT angiography was considered and what each costs at this facility — they answer overlapping questions at different prices.
• Ask for the facility's cash price as well as the insured price. For repeated vascular surveillance the difference compounds over years.