Scans and imaging tests
Imaging tests allow doctors to take detailed images of your internal organs and tissue, and assess the size, shape and surface appearance of your liver. They can also test the stiffness of the liver – healthy liver tissue is soft, so stiffness indicates that damage has occurred.
If you are required to undergo a liver biopsy you may need to have an ultrasound scan first.
Ultrasound is a routine procedure which can provide very useful information. It is usually performed in the X-ray department of the hospital or in an outpatient’s clinic, day care department or on a ward. Unlike an X-ray, ultrasound does not use radioactive waves. The procedure is very safe and should not be painful, and takes around 10 to 15 minutes to complete.
Before the scan you will be asked to uncover the top of the right half of your tummy (below your ribs, which is where your liver is) and lie on your back. Gel will be applied to your skin which may feel slightly cold. A probe shaped like a microphone will be moved across the surface of your skin. The gel helps to make this movement easier and makes sure that sound waves can be directed through your skin as the probe passes over your liver area.
The ultrasound machine will record the pictures of your liver. A report will be made by the radiologist, who is trained to examine the images. This report may be ready soon after your ultrasound or may take one to two weeks. It will provide you and your specialist with information about the surface and shape of your liver, and its general appearance, and highlight unexpected changes or anything that is not normal.
There is a technique similar to ultrasound, known as elastography, or transient elastography, which doctors can use to measure the stiffness of the liver. Healthy liver tissue is soft, so if stiffness is detected, fibrosis (scar tissue) may be present. The most common name for this kind of test is FibroScan. Tests such as FibroScan can’t diagnose specific liver diseases but they can give doctors an idea of how badly the liver is damaged.
Sheer wave elastography (SWE)
This is a more advanced version of the technique described above, which uses a focused ultrasound wave to give radiologists a clearer picture of how ‘elastic’ (soft) the liver is. The waves travel slowly through healthy liver tissue and faster through scarred areas.
Acoustic radiation force impulse imaging (ARFI)
This is another imaging technique. It works by ‘pushing’ the tissues in the body to assess their stiffness – softer, healthy tissue is more easily pushed than stiffer tissue, which may indicate fibrosis.
CT scan (computed tomography scan)
This scan is useful for showing several types of tissue very clearly, most commonly the lungs, bones, soft tissues and blood vessels. A CT scan is one of the best tools for studying the chest and abdomen (stomach area), and is particularly useful in detecting excess fat in the liver (fatty liver). Sometimes CT scans are also used to help guide doctors using needles for biopsies.
The CT scanner itself is a large ring-shaped machine into which you will be moved backwards and forwards. This is to allow the scanner to send a number of narrow beams across your body in a circular motion to provide very detailed images of the area under examination. It takes around 10 minutes, unless many pictures are required, which may take 20 to 30 minutes.
MRI (magnetic resonance imaging)
MRI uses a type of tube scanner to provide a more detailed view of your organs than a CT scan. It is a very useful tool for investigating tumours both before and after treatment. A type of MRI scan called Liver MultiScan is sometimes used to accurately measure the amount of fat, fibrosis (scarring) and inflammation present in the liver.
You will be required to remain very still. The scan isn’t at all painful, although some people may find being inside the scanner claustrophobic. It can take up to one hour but the majority of scans will take between 20 and 30 minutes.
MRE (magnetic resonance elastography)
This is an MRI-based advanced technology that uses imaging with soundwaves to create a detailed picture of the body, and is particularly good at showing hardening and stiffness of liver tissue. A small pad is placed on the skin, through which low-frequency vibrations are passed into the liver. A computer measures the speed at which tissues in the liver vibrate – the quicker the vibrations, the more fibrosis is present. MRE can detect fibrosis at an earlier stage than other tests, and give an indication of how severe the fibrosis is.
MRCP (magnetic resonance cholangiopancreatography)
MRCP is a test using specialised magnetic resonance imaging (MRI, above) to provide doctors with a picture of your biliary (bile-carrying) and pancreatic ducts. In this scan, the fluid in your biliary ducts appears brighter while the surrounding organs and tissues will appear darker.
The procedure can be used to find out whether gallstones are lodged in any of the ducts surrounding your gallbladder. The scan is painless and takes about ten minutes unless combined with a normal MRI scan (an extra 20 to 30 minutes) and is normally performed as an outpatient appointment.
An X-ray is a common and painless examination in which invisible radioactive waves are passed through your body to record an image of your internal organs. A special X-ray that studies the veins and arteries that supply blood to the liver is known as hepatic angiography. This X-ray may be needed if your diagnosis is still doubtful after a CT and MRI scan. The procedure uses a catheter (a thin, flexible tube) that is placed into blood vessel though a small cut in your groin. A dye, referred to as a ‘contrast dye’ or ‘contrast medium’, is then injected through the catheter to light up the blood vessels to make them easier to see. A hepatic angiogram is usually done under local anaesthetic and you are also likely to be given sedation. Because of this, you may be asked to stay in hospital overnight (the minimum stay is six hours). The test is usually uncomfortable, rather than painful. You should be able to drive the next day.
For further information about these tests talk to your specialist or your medical team.