Imaging tests allow doctors to examine you by looking at still and moving images of your internal organs and tissue. The consultant who will arrange and supervise your test is a radiologist. The medical staff that operate the imaging equipment are called radiographers.
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 (see ‘X-rays’ page 31) ultrasound does not use radioactive waves. The procedure is very safe and should not be painful, but it may take 10 to 15 minutes to complete.
Before the scan you will be asked to uncover the top of the right half of your abdomen (below your ribs) and lie on your back. Gel will be applied to your skin which may feel slightly cold. A probe, 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. Anything solid will bounce back as a reflected sound wave via the probe and will be turned into an image that can be seen on a screen.
Once the procedure is finished and the probe removed, the gel is wiped off your skin. You will then be able to go home or on to an appointment if one is scheduled. If you are a hospital patient you will be advised whether you are to stay or go home.
The ultrasound machine will have recorded 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. You should have an appointment arranged to discuss the result with your specialist or medical advisor. Sometimes the specialist will describe the type of picture received from your liver ultrasound as being ‘echogenic’. This means how clearly or ‘bright’ your liver can be seen on the ultrasound. The report will provide you and your specialist with information about the surface and the general shape of your liver, as well as any significant changes from its normal appearance. While ultrasound is able to highlight unexpected changes or anything that is not normal, it cannot show these in detail.
If you have any concerns about your liver ultrasound, discuss these with your doctor or nursing staff. Do this either when they are arranging your appointment or while you are having the ultrasound, to make sure you have the answers you need.
CT scan (computed tomography)
This test uses special X-ray equipment to demonstrate the density (thickness) of your body tissues. It can obtain pictures, called tomograms, from different angles around your body using computer processing and can show cross sections or ‘slices’ of your tissue and organs. This scan is useful for showing several types of tissue very clearly. The types of tissue investigated are the lungs, bones, soft tissues and blood vessels.
The CT scan is one of the best tools for studying your chest and abdomen. It can be used to find out whether you have excess fat in your liver (fatty liver). Sometimes CT scans are also used by doctors to help guide entrance sites for biopsies. To prepare for the test you should wear comfortable clothing. You will be asked to remove all metal objects including hairpins, jewellery, hearing aids, removable dental work and glasses. CT scanning is not painful. An iodine dye, usually given as a fluid to swallow, is used to show up the gullet (oesophagus), stomach and intestines (small bowel and colon). Alternatively, a dye may be injected into a vein to make your blood vessels and kidneys easier to see and to highlight the appearance of normal and abnormal tissue in organs such as the liver and spleen.
The CT scanner itself is a large 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 is possible for the scan to take only several minutes unless many pictures are required (perhaps 20 to 30 minutes). There is a slight exposure to radiation, but for the time this test takes the risk is considered minimal. You are unlikely to have this scan if you are pregnant. The risk of allergic reactions to iodine dye material is rare and radiology departments are well equipped to deal with them should they occur.
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 relatively new kind of technology that creates powerful magnetic fields by releasing radio frequency energy to act on water molecules in your body. These emissions are a type of radio signal that can be picked up by the MRI equipment and relayed to a computer that is able to generate very detailed views of tissues within your body. For this reason MRI is a very useful tool for investigating tumours both before and after treatment.
You will be required to remain very still. The scan is painless 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.
Preparation and guidelines for the scan are similar to those for the CT scan. Although most people with metal in their bodies will be able to have MRI, people with certain implants may not. Your radiologist will advise.
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. Again, you will be asked to prepare for this examination in very much the same way as for a CT or MRI scan.
In X-ray is a common and painless examination in which invisible radioactive waves are passed through your body to record an image of your body 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 a blood vessel through 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.