Liver ultrasound scan: preparation, what happens and what it shows

An ultrasound scan uses high-frequency sound waves to create an image of the inside of the body. Cambridge University Hospitals explains that gel is applied and a small plastic probe (transducer) is slowly moved over the area, sending sound waves into the body, and the machine creates images from the reflections. Liver UK says it is a very common test used to look at the liver, gallbladder or other parts of the tummy, usually done in hospital by a sonographer or a radiologist.

A liver ultrasound is often part of an upper abdominal ultrasound, which also looks at the gallbladder, bile ducts, pancreas, spleen and kidneys. It shows the size, shape and texture of the liver, and can detect fat, cysts, solid lumps, gallstones, and bile duct widening.

The NHS says ultrasound is used to investigate symptoms such as pain or a lump and to monitor a condition. For the liver, common reasons include abnormal liver blood tests, tummy pain in the upper right side, jaundice, suspected gallstones, an enlarged liver on examination, monitoring of known liver disease such as fatty liver or cirrhosis, and surveillance for liver cancer in people at high risk.

The NHS lists a GP arranging an ultrasound scan of the tummy among the steps to confirm a build-up of fat in the liver, rule out other causes of liver problems and check for damage in non-alcoholic fatty liver disease.

Always follow your appointment letter. Liver UK says you may be asked to fast for 6 hours and not to have food, drinks with milk, fizzy drinks or alcohol, though water or tea or coffee without milk or sugar is fine. Cambridge University Hospitals asks patients not to eat anything for six hours and to drink clear fluids only, and says this improves the quality of images, particularly of the gallbladder.

Carry on with medicines as normal unless instructed. If fasting would cause problems, for example if you have diabetes or need food with medicines, contact the scanning department in advance. Liver UK notes that for liver and gallbladder scans you do not usually need to arrive with a full bladder, unless your letter says so, which differs from pelvic scans.

Wear loose clothing with a separate top and bottom, as you will need to lift or remove your top. Scan appointments do not always run on time, so a bottle of water, something to read and a snack for afterwards are sensible.

Liver UK says the scan room may have dim lights so that the images can be seen clearly. You lie on a bed, pull up or take off your top and may be given paper towels to tuck into clothing. Clear gel, which can feel cold, is put on the right side of the tummy around the bottom of the ribs, and the probe is moved around to see different parts of your liver and gallbladder and the areas around them. You might feel some pushing, which can be uncomfortable but should not be painful.

You may be asked to roll onto your side, hold your breath or lift your arms over your head to improve the pictures. You may hear swooshing or pulsing sounds, which is the sound of blood flowing through the liver. The scan might also look at other organs such as the spleen. The sonographer saves still pictures and videos. At the end you wipe off the gel and can eat and drink as normal.

Liver UK says ultrasound scans are very useful, but often cannot give a definite diagnosis on their own, so you might be asked to have other imaging tests such as CT or MRI, or further blood tests. Sometimes an ultrasound and blood tests are enough to diagnose or rule out a liver problem.

Liver UK says there are some very common and harmless liver conditions that are often picked up by accident during an ultrasound for something else. Simple liver cysts are small sacs of liquid that usually cause no problems or symptoms, and the safest option is to leave them alone. Liver haemangiomas are a very common type of benign tumour thought to affect about 1 in 20 people, and it is very rare for them to cause symptoms.

If your scan shows one of these you might be asked to have other tests to rule out rarer conditions. Liver UK says this is nothing to worry about.

The person doing the scan may be able to tell you something they can see, but usually the scan needs to be looked at in more detail. The report is written and sent to the doctor who requested the scan, who will look at it alongside other test results. Liver UK says that if you do not already have a follow-up appointment you should contact the GP or hospital team that referred you, and that it should be about 2 weeks after the scan.

Cambridge University Hospitals says the risks are very low; there is a very low risk of infection from the gel, reduced by wiping it off thoroughly.

On the NHS, a GP or hospital doctor requests the scan and it is done in a hospital or community diagnostic centre, with waiting times that vary by area. Urgent scans are prioritised for people with suspected cancer or jaundice.

Private ultrasound is widely available without a referral and often within days. The scan technique is the same, but the report should be shared with your GP, and any abnormality will normally lead to NHS follow-up. Be cautious about ultrasound offered as a screening service without a clinical reason, because incidental findings can cause worry without benefit.