About an MR angiogram of the iliac arteries
The aorta, the body’s main artery, divides just below the belly button into the two iliac arteries. These run through the pelvis and carry blood to the legs and the pelvic organs. An MR angiogram (MRA) uses a strong magnetic field, radio waves and a computer to make detailed pictures of these arteries, without X-rays and without passing a tube (catheter) into an artery.
The scan is most often used when narrowing of the aorta or iliac arteries is suspected. This is called aortoiliac occlusive disease and is a form of peripheral arterial disease, usually caused by a build-up of fatty plaque in the artery walls. Some people have no symptoms; others get pain, cramping or tiredness in the buttocks, thighs or calves when walking, which eases with rest. In men it can also cause erectile dysfunction. Smoking, diabetes, high blood pressure and high cholesterol all increase the risk.
Simpler tests such as an ankle-brachial pressure index and a duplex ultrasound scan usually come first. An MR angiogram is used when more detail is needed, particularly to plan treatment such as angioplasty, a stent or bypass surgery.
Referral needed: this scan requires a referral from a specialist, such as a vascular surgeon, stroke physician or other hospital consultant. You can upload the referral when you book.
What happens during the scan
You lie on your back on the scanner bed with a coil placed over your tummy and pelvis. The scanner is loud, so you will wear ear plugs or headphones, and the radiographer can see, hear and talk to you throughout. You will need to keep your body very still, as even small movements can blur the pictures of the blood vessels.
Most MR angiograms use an injection of contrast dye (gadolinium) through a small cannula in a vein, usually in your arm or hand, so the blood vessels show up clearly. Gadolinium is less likely to cause an allergic reaction than the iodine-based dye used for CT. Some vessels can also be imaged without contrast. If you have contrast, you may be asked to wait for up to 30 minutes afterwards. Where contrast is needed, it is charged separately.
What the scan can show
An MR angiogram of the iliac arteries can help to look at:
- narrowing (stenosis) or blockage of the iliac arteries and lower aorta
- where and how long any narrowing is, to help plan angioplasty, stenting or bypass surgery
- aneurysms (swellings) of the iliac arteries
- how well a stent or bypass graft is working after treatment
- narrowing caused by inflammatory conditions of the arteries, or by previous radiotherapy to the pelvis
MRA does not show calcium in the artery walls as clearly as a CT angiogram. Your specialist will advise which test suits you best.
Sudden symptoms? If a leg or foot suddenly becomes painful, pale, cold or numb, get urgent medical help straight away rather than waiting for a scan.
Preparing for your scan
You may be asked not to eat for a few hours before the scan. The scanning centre will confirm this when you book. Because MR angiograms usually use contrast dye, let us know if you have kidney problems or have had a reaction to contrast before. If you have diabetes, tell us when booking.
You can usually eat, drink and take your normal medicines unless the scanning centre tells you otherwise. Wear loose, comfortable clothing without metal zips or buttons, and leave jewellery at home. You will be asked to remove metal items such as hair clips, hearing aids, coins and keys, and you may be asked to change into a gown.
Before the scan you will complete a safety questionnaire. Tell the team if you have a pacemaker, any metal implant, surgical clips or other device, if you have kidney problems or allergies, or if you are, or might be, pregnant or breastfeeding. If you feel anxious in enclosed spaces, let us know when you book. Some centres can offer a relaxant, and if you take one you will need someone to take you home and must not drive for 24 hours.
Frequently asked questions
Do I need a referral for an MR angiogram of the iliac arteries?
Yes. This scan requires a referral from a specialist. Please upload your referral when you book so the scanning centre can check that the right scan is arranged.
What is aortoiliac occlusive disease?
It is narrowing or blockage of the lower aorta or the iliac arteries, usually caused by fatty plaque. It can cause pain or cramping in the buttocks, thighs or calves when walking, and erectile dysfunction in men, although some people have no symptoms.
Will I need a contrast injection?
Usually, yes. Contrast dye helps the arteries show clearly. It is given through a small cannula in your arm and is charged separately where it is needed.
How is an MR angiogram different from a normal angiogram?
A traditional (catheter) angiogram involves passing a thin tube into an artery, usually from the groin or wrist, and uses X-rays. An MR angiogram uses an MRI scanner, with at most an injection into a vein in your arm, so there is no catheter and no radiation.
Sources
- MetroHealth – Aortoiliac occlusive disease
- NHS – Peripheral arterial disease (PAD)
- RadiologyInfo.org – Magnetic Resonance Angiography (MRA)
- NHS – MRI scan
The information on this page has been gathered from various sources and is provided for general information only. It is not medical advice. TOP MRI is not liable for the accuracy or completeness of this information. Please speak to your doctor or the scanning centre about your own situation.