Adrenal MRI:what to expect

Your doctor may recommend an Adrenal MRI to look closely at the adrenal glands, especially if you have:

• An adrenal mass found by accident on a CT, ultrasound, or other scan (an "incidentaloma").
• Symptoms or blood tests suggesting a pheochromocytoma, a hormone-producing tumour of the adrenal gland.
• A known cancer elsewhere — especially lung, breast, or kidney — with an adrenal lesion that needs characterising.
• A known adrenal lesion under follow-up, with a need to check whether it has changed.
• High blood pressure that is hard to control, when your doctor wants to rule out an adrenal cause.

An Adrenal MRI helps doctors see:

• Adrenal adenomas — the commonest type of adrenal mass, almost always benign.
• Pheochromocytomas, which often have a characteristic appearance.
• Adrenal metastases from cancers elsewhere in the body.
• Adrenal carcinomas, which are rare but important to identify.
• Adrenal cysts, haemorrhages, and myelolipomas (a benign mix of fat and bone marrow tissue).
• Whether a known lesion is stable, growing, or changing in character.

Sometimes, but not always. A large part of the value of this scan comes from the no-contrast chemical shift images. Gadolinium contrast may be added if the lesion looks unusual, if a pheochromocytoma is suspected, or if the team needs to look at blood vessels around the gland. Your radiologist will decide based on what the team needs to know.

Chemical shift imaging uses two sets of images — one called "in-phase" and one called "opposed-phase" — to detect microscopic fat inside a lesion. Signal loss on opposed-phase images strongly supports a lipid-rich adrenal adenoma, but not every adenoma behaves this way and uncommon mimics exist. The radiologist combines this finding with lesion size, shape, previous imaging, and hormone tests before recommending follow-up or further assessment.

No. The scan only shows what the mass looks like — its size, shape, fat content, and how it takes up dye. It cannot tell whether the gland is producing too much cortisol, aldosterone, or adrenaline. Hormone activity is checked with separate blood and urine tests, which your doctor will arrange. The two sets of results are then combined to decide what the mass is and whether it needs treatment.

A CT of the adrenals uses radiation and an iodine-based dye and is excellent for measuring the density of an adrenal mass — which also helps tell adenomas apart from other lesions. Adrenal MRI uses no radiation, uses chemical shift imaging instead, and gives a clearer picture of the soft tissue around the gland. Many patients have a CT first and an MRI only if the CT findings are uncertain — or when the doctor wants to avoid radiation, for example in younger patients or those who will need repeated scans.

Preparation is straightforward:

• You do not need to fast in most centers.
• A cannula will be placed in your arm if contrast is planned.
• Remove all jewellery, body piercings, and metal objects, and change into a hospital gown.
• Tell the team about any implants, especially pacemakers or surgical metal.
• If you have known kidney disease, a recent blood test may be requested before contrast is given.

The scan is painless. You will lie on your back on a padded table that slides into the MRI scanner.

A receiving device (a coil) will be placed over your upper abdomen. The scanner makes loud knocking and humming sounds, and earplugs or headphones will be provided. You will be asked to hold your breath for 10 to 20 seconds at a time during the key sequences, so the adrenal glands do not move with breathing. The radiographer will speak to you between sequences.

The scan usually takes 25 to 40 minutes inside the scanner. Including changing and cannula placement, the whole appointment is usually about an hour.

It is normal to feel anxious, especially during the breath-holds. The radiographer will be in contact with you the entire time and you can hold a squeeze ball to alert them if you need a break. If you are very claustrophobic, ask your doctor about a mild sedative beforehand.

A Radiologist will review the images and prepare a detailed report for your referring doctor. Results are typically ready within a few days. Your doctor will combine the scan findings with your hormone blood and urine tests before deciding on next steps.

The scan uses no radiation and is safe in principle. In pregnancy, contrast is generally avoided, and the scan is performed only when the result will change immediate care. In children, it is used selectively for specific tumours and is preferred over repeated CT because it avoids radiation.

• RadiologyInfo: MRI of the body
• ACR Manual on MR Safety
• FDA: MRI benefits and risks

An Adrenal MRI is the most powerful non-invasive way to characterise an adrenal mass. For most people who came in with an incidental finding, the scan provides a clear answer and avoids the need for biopsy or surgery. Bring any previous scans or reports with you so the team can compare and look for changes.