Shoulder MRI (with contrast)

What it is

A plain shoulder MRI can miss a small tear, because a torn edge that is still lying flat against the tissue it came off looks much like intact tissue. The fix is mechanical rather than chemical: fill the joint with fluid until it is gently distended, and the fluid finds its way into any split, outlining it. That is an MR arthrogram — a radiologist numbs the skin, guides a thin needle into the joint under x-ray or ultrasound, injects a dilute gadolinium solution, and the patient then goes into the scanner. Because imaging happens after contrast has been given, the scan itself is billed as a with-contrast study. The injection is a separate procedure with its own charge, and so is the guidance used to place the needle. Not every shoulder study under this code is an arthrogram, but in this joint it is the usual reason for one.

Why it is done

• To look for a tear in the labrum, the cartilage rim around the socket, which is a common finding after a dislocation and is hard to see without the joint distended
• To assess shoulder instability, where the shoulder slips or feels like it will
• To find a partial-thickness tear on the underside of the rotator cuff that a plain scan may not resolve
• To examine a shoulder that has already been operated on, where scar and retear look similar on standard images
• To answer a specific surgical question before an arthroscopy

What to expect

This is a two-part appointment. The injection happens first, in a fluoroscopy or ultrasound room: the skin is cleaned and numbed, a needle is placed into the joint, and the solution goes in. People commonly describe pressure and a full, tight feeling in the shoulder rather than sharp pain. Then you move to the MRI scanner, usually within the next half hour or so, because the point is to image while the joint is still distended. The scan itself runs about the same length as any shoulder MRI. The fullness settles over the following day, and mild aching afterward is common.

Questions worth asking

• Expect three charges, not one: the joint injection, the imaging guidance used to place the needle, and the MRI. Ask for an estimate that lists all three.
• The doctor who performs the injection may bill separately from the radiologist who reads the scan. Ask whether both are in your network.
• Ask whether the injection and the scan are scheduled at the same site. If they are in different buildings you may be billed two facility charges.
• Ask what happens to the bill if the injection cannot be completed and the study reverts to a plain MRI.
• If contrast is being given by vein rather than into the joint, ask why a before-and-after study was not ordered instead — that is a different code and answers a different question.