MRI of the liver: what it shows, preparation and what to expect

MRI stands for magnetic resonance imaging. The NHS says an MRI scan takes detailed pictures of the inside of your body and is used to help diagnose conditions, plan treatment and check how well treatment is working. A liver MRI focuses on the upper abdomen. The Lancashire leaflet explains that a device called a coil is placed on your abdomen to improve the quality of the images, and that the scanner is an open-ended tube surrounded by a large circular magnet.

Because the scanner uses a strong magnet, it is not suitable for everyone, particularly people with certain implants, which is why a safety questionnaire is completed before every scan.

The NHS lists scans among the tests used when liver cancer is suspected, naming ultrasound, CT and MRI, together with blood tests and sometimes a biopsy. It says the tests can also help find problems in the bile ducts, pancreas or gallbladder. A liver MRI may therefore be requested to look more closely at a finding from another test, to investigate symptoms or abnormal blood tests, or to monitor a known liver condition.

The sources read for this page do not list every indication, and the reason for your scan will be stated on the request. If you are unsure why you have been referred, ask the doctor who requested it.

Preparation varies between hospitals, so your appointment letter takes priority. Lancashire says you can eat and drink as normal unless advised otherwise, and asks you to leave valuables at home and remove jewellery. University Hospitals Plymouth's easy-read leaflet asks you not to eat anything for 4 hours beforehand and to drink only water or squash. NHS Highland asks you to continue prescribed medication, to wear loose clothing with no zips or metal or change into a gown, to avoid mascara because it contains iron that can interfere with image quality, and to be well hydrated because contrast will be injected.

You will complete a safety questionnaire. The Lancashire leaflet asks you to contact the department beforehand if you have a pacemaker or implanted defibrillator, neuro-stimulator, cochlear implant, aneurysm clip, shunt in the head, metal fragments in the eye, shrapnel, recent endoscopy with clips or a capsule, are pregnant, weigh over 200 kg, cannot lie flat or keep still, have had an allergic reaction to gadolinium or have kidney problems. NHS Highland also asks about continuous glucose monitors such as Libre, and about surgery in the last 6 weeks.

You lie on the scanning table with your abdomen in the centre of the tube. You are given a buzzer to press if you need the radiographer, who sees you through a window and speaks via an intercom. There will be repeated loud banging, buzzing and tapping, and you will be given earplugs and headphones. It is important to stay very still because movement affects the pictures, and you will be asked to hold your breath for short periods for most of the pictures, which are timed in short bursts.

The Lancashire leaflet says the contrast injection is gadolinium, given through a cannula in your arm or the back of your hand, to make the liver more visible. A very small number of people are allergic, reactions are rare and mostly mild, and it asks you to tell the radiographer about allergies, kidney problems or breastfeeding. It notes that small amounts of gadolinium may remain in tissues after an injection, with no evidence that these cause harm. You are advised to stay in the department for 30 minutes afterwards.

NHS Highland describes a liver scan done in two parts: the first takes about 40 minutes, then a break of about an hour, during which you may leave the department, then a second scan of about 10 minutes, with 2 to 2.5 hours in total. Not every hospital does this, so check your letter.

You can usually go home straight away, eat and drink as normal and carry on with your day, unless you had a sedative. The NHS says the radiographer cannot give results on the day because the images must be reviewed by a radiologist, who writes to the doctor who referred you. It usually takes 1 to 2 weeks, and you may need a follow-up appointment. If you have not heard after a few weeks, contact the doctor who referred you.

The NHS notes that complications are rare. Contrast can cause side effects that are usually mild, such as feeling sick, a skin rash, headache, a metallic taste or dizziness, and rarely allergic reactions with breathing difficulty. Tell the radiographer if you feel unwell, and call 999 or go to A&E if you develop breathing difficulty or swelling of the face after leaving.

On the NHS, a liver MRI is requested by a GP or hospital specialist and prioritised by clinical urgency, with the suspected-cancer pathway moving faster. Private MRI is also available in the UK, and the preparation, contrast and safety checks are similar. In either setting a consultant radiologist reports the images and the result should be explained to you by the requesting doctor.