CT Scan – Adrenal Glands

About a CT scan of the adrenal glands

The adrenal glands are two small glands that sit on top of the kidneys. They make hormones including cortisol, aldosterone and adrenaline, which help control blood pressure, blood sugar, salt balance and the body’s response to stress. A CT (computed tomography) scan uses X-rays and a computer to make thin, detailed cross-section pictures of the glands.

The most common reason for an adrenal CT is an adrenal incidentaloma: a lump in an adrenal gland found by chance on a scan done for another reason. These are common, especially in older adults, and most are harmless growths called adenomas that do not make extra hormones. CT is the main test used to tell them apart from other lumps. A scan without contrast measures the density of the lump: adenomas usually contain fat and look less dense, and a small, smooth lump below a set density usually needs no further scans. If the result is not clear, pictures may be taken after an injection of contrast dye and again a few minutes later (an adrenal “washout” scan), to see how quickly the dye clears.

An adrenal CT is also used, alongside blood and urine tests, to look for the cause of hormone problems such as Cushing’s syndrome (too much cortisol), Conn’s syndrome (too much aldosterone, which causes high blood pressure) or a phaeochromocytoma (a rare growth that makes too much adrenaline). The hormone tests are usually done first, and an endocrinologist (hormone specialist) will interpret the results together. MRI is an alternative without radiation; see adrenal glands MRI.

What happens during the scan

You lie on your back on the scanner bed with your arms raised above your head. The bed moves slowly through a short, open ring while the upper part of your tummy is scanned. The radiographer controls the scanner from the next room, but can see, hear and talk to you throughout. You will be asked to hold your breath for a few seconds at a time. If contrast is used, you may stay on the bed for around 15 minutes so that delayed pictures can be taken.

For some CT scans, an injection of contrast dye is given through a small cannula in a vein, usually in your arm or hand, to make blood vessels and organs show up more clearly. CT contrast contains iodine. As it goes in you may feel warm and flushed, notice a metallic taste, or feel as if you are passing urine; these feelings pass within a minute or two. Allergic reactions are uncommon, and you may be asked to wait for up to 30 minutes afterwards. Where contrast is needed, it is charged separately.

Is CT safe?

CT uses X-rays, which are a type of ionising radiation. A scan of the adrenal glands covers only part of the abdomen, so the dose is usually lower than for a full CT of the abdomen and pelvis (about 10 mSv, similar to around 4.5 years of natural background radiation). The risk from a single scan is very small, and every CT scan is checked by a radiologist or radiographer to make sure the benefit of the scan outweighs the risk, as required by the Ionising Radiation (Medical Exposure) Regulations. If you have had other CT scans recently, tell us when you book.