What is a FibroScan and why would I need one?
Written in association with:
Hepatologist
Published: 20/07/2018
Edited by: Emily Lawrenson
FibroScan is one of the latest developments in the diagnosis and management of liver diseases, completely changing assessment from a liver biopsy (taking a sample of tissue) with results coming back after several days, to a non-invasive procedure with results offered on the very same day at the very same consultation. Leading hepatologist Professor Kevin Moore explains more about what a FibroScan is, and how it works.
What is a FibroScan?
A FibroScan is a type of ultrasound which measures how much scarring there is in your liver due to liver disease. It is quick, painless and frequently obviates the need for a liver biopsy.
Liver disease covers a range of conditions including fatty liver disease, chronic viral hepatitis, excess alcohol over the years, or other diseases such as autoimmune liver disease or hemochromatosis. One thing all of these liver diseases have in common, is that over the years they cause low grade chronic inflammation and scarring of the liver. It is this scarring or liver fibrosis that is important, as early scarring of the liver is the forerunner to the development and establishment of liver cirrhosis. A FibroScan allows the tracking and monitoring of liver fibrosis and disease, allowing the physician or hepatologist and patients to see an immediate readout enabling decision making and advice there and then without a liver biopsy.
How does a FibroScan work?
In brief: In essence the machine works by flicking the skin over the liver, and measuring the wobbliness of the liver. In the same way that if you flick a jelly it wobbles, you can imagine that if you flick the same jelly that is encased with lots of scar tissue (fibrosis) it simply won’t wobble as much. Thus, a healthy liver is a wobbly liver.
The new FibroScan machines measure two things, one being the stiffness of the liver – a healthy liver is ‘wobbly’, rather like a jelly – and the other being the amount of fat in the liver (or CAP score). Earlier FibroScan machines measure liver stiffness and pressure alone.
FibroScan machines use elastography, which is similar to ultrasound. The machine uses a probe, positioned against the liver and between the ribs, to send out pulses and assess how stiff the liver is. The pulses feel like a gentle ‘flick’ against the skin, but they are not painful. These pulses send out sound waves, and the FibroScan measures how long these waves take to bounce back, thus determining the stiffness of the liver.
The procedure is non-invasive, and after it has been performed, you can immediately return to work, or go home. Results are immediate and will either be sent to a specialist for review, or given to you on the day if your consultation has been arranged with a liver specialist.
False Positives: There may be a false positive value i.e. one consistent with cirrhosis or significant fibrosis in patients with heart failure, actively drinking alcohol, eating before the procedure etc.
What do FibroScan results mean?
Values seen in clinical practice:
Normal liver stiffness
<6.0kPa
Mild to severe fibrosis
6.1-11.9 kPa
Cirrhosis
>12.0 kPa
Normal liver fat:
CAP <220 DbM
Fatty liver:
CAP 221-300 DbM
Severe fatty liver:
CAP >300 DbM