What is a magnetic resonance angiogram (MRA) scan?

Sometimes known as magnetic resonance angiography, an MRA uses magnetic resonance imaging (MRI) to look at your body’s blood vessels and blood flow.

When it’s used to diagnose kidney conditions, an MRA looks at the renal arteries (the blood vessels that supply your kidneys).

What does an MRA involve? 

An MRA is a day procedure in hospital.

You lie inside a large tube that’s open at both ends, while the scanner takes detailed images of your renal arteries using a strong magnetic field and radio waves.

A contrast dye is injected so that the arteries can be seen more clearly in the images, which can be rotated so that doctors can view them from different angles.

Who is an MRA for?

Doctors may recommend this test to help identify diseased or malformed blood vessels. It may also be used to monitor a condition that’s already been diagnosed.

Is it safe? Are there any alternatives?

MRA is generally considered very safe. There’s no evidence that the magnetic fields used are harmful, and MRI departments have safety procedures in place.

Some scanners can affect the functioning of implanted devices, including pacemakers and cochlear implants. The hospital will carry out a safety assessment in advance. This will include questions about whether you have any implanted devices or any metal in your body that can’t be removed, such as piercings you can’t take out.

There’s no evidence that MRA is harmful in pregnancy.

If you are breastfeeding, it is safe to continue breastfeeding after the contrast dye is given. It is not thought to present any danger to your child as the amount received by your baby through breast milk is small.

Where will the MRA scan take place? 

In the radiology/X-ray department of the hospital.

It will be carried out by a radiographer, who is trained in this type of imaging test and will operate the scanner.

What happens before an MRA scan procedure? 

Some medications may need to be stopped before the procedure. You’ll be asked in advance about any medications you take, so follow the guidance you’re given.

You may be asked to avoid wearing anything containing metal on the day, including anything with zippers or metal buttons.

You’ll need to remove items such as hearing aids, watches and jewellery before going into the scanner. A locker will be provided in the hospital.

What happens during the procedure? 

• The radiographer will discuss your safety assessment and you may have a blood test to look at blood clotting, blood count and kidney function.
• You may be given fluid to drink. You’ll empty your bladder before the scan.
• You’ll be given an injection with contrast dye so the pictures taken will show more detail.
• Then you’ll be asked to lie on a bed and you’ll be given ear protection to wear because MRI scanners make loud noises when the small magnets inside click on and off. You’ll have a call button, which you can use if you need to stop the scan.
• The radiographer will go into another room to operate the scanner. You’ll be able to hear and speak to them throughout the scan.
• The procedure may be uncomfortable because you’ll need to lie very still to ensure the pictures aren’t blurred, and you may be asked to hold your breath at certain points.

The scan usually takes between 20 minutes and an hour.

What happens immediately after the procedure?

You may be asked to stay in the hospital for 30 minutes so that staff can make sure you don’t have a reaction to the contrast dye.

What should I expect when I get home? 

You should be able to carry on with your usual activities straight away.

How will I get the results? 

A radiologist – a doctor specialising in interpreting images – will prepare a report and send it to the doctor who referred you for the MRA, who will discuss the results and next steps with you.

Is there anything else I need to know? 

Tell the hospital team if you’re worried about feeling claustrophobic in the MRI scanner. The scanner is open-ended so you will not be fully enclosed. Your hospital team can help you to manage any anxiety.

Publication date: 01/2026

Review date: 01/2029

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