A liver elastography is an imaging test that doctors use to diagnose liver scarring, known as fibrosis. Scarred liver tissue is thicker and less flexible than healthy liver tissue, and it prevents the organ from functioning properly.

An elastography involves passing low frequency vibrations through the body during an ultrasound scan or MRI scan. The vibrations travel through healthy and diseased tissue at different speeds. A computer program records the speed of these vibrations and uses the data to create an image of the liver. This helps doctors determine the presence and severity of liver disease.

This article describes what a liver elastography is and what to expect during the procedure. It also explains how doctors use the results to diagnose fibrosis and predict disease outcomes.

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A liver elastography is a noninvasive procedure that doctors use to determine the health of a person’s liver. The procedure assesses the thickness and elasticity of liver tissue, with thicker and less elastic tissue indicating fibrosis. This condition limits blood flow to the liver, impairing its function.

Liver elastography involves measuring the time it takes for low frequency vibrations to pass through the liver. Areas of scarring slow down the vibrations, so they pass through less quickly than they would in a healthy liver.

There are two main types of liver elastography: ultrasound elastography (UE) and magnetic resonance elastography (MRE). Ultrasound uses sound waves to produce the necessary vibrations, while magnetic resonance uses a combination of MRI imaging and low frequency vibrations. MRE usually covers a larger portion of the liver.

Doctors use liver elastography tests to diagnose liver fibrosis or estimate its severity.

Liver fibrosis describes a hardening and stiffening of the liver tissue. Without treatment, it can develop into a more severe and irreversible pattern of liver damage called cirrhosis. The American Liver Foundation (ALF) explains that people with cirrhosis may go on to develop liver failure, for which the only treatment is a liver transplant.

However, the ALF notes that diagnosing and treating fibrosis at an early stage can help the liver repair itself and stop liver disease from progressing.

Doctors started using liver elastography tests in the early 2000s as an alternative to a liver biopsy. A biopsy is a more invasive test, which involves removing a sample of liver tissue to examine under a microscope.

Some people with early stage liver disease do not experience symptoms. If symptoms do occur, they may include the following:

Below are some tips on what to expect before, during, and after a liver elastography.

Before the procedure

Most people undergoing liver elastography need to fast for 6–8 hours before the procedure, but a person should follow their doctor’s specific recommendations.

Certain foods and sugary drinks can affect liver stiffness. As such, doctors may advise eating a light, fat-free meal the evening before the procedure and avoiding sweet beverages.

During the procedure

Below is some information on what to expect during a UE and an MRE.

Ultrasound elastography

During a UE, a person lies on their back, with their abdomen exposed. The radiographer spreads a gel over the right abdominal area and then moves a device called a transducer over the area.

The transducer is a wand-like device that emits a series of sound waves. These sound waves bounce off the liver as echoes. A computer program translates these echoes to build up a picture of the liver. The procedure typically takes about 5 minutes.

Magnetic resonance elastography

When preparing for an MRE, a person must remove any metal items, such as dental braces, jewelry, and clothing with metal zips or fastenings. They must also inform the radiographer of any internal metal or electronic devices, as these can interfere with the magnets inside the scanner.

The person then lies on a narrow table that moves into a large, tunnel-shaped MRI machine. The machine contains magnets that emit a loud sound during activation. A person will receive earplugs to help reduce the noise.

Once the person is inside the MRI scanner, a small pad on the abdomen sends vibrations into the liver. A computer program records and translates this information to build up a picture of the liver.

An MRE typically takes 30–60 minutes.

Ultrasound elastography is a noninvasive test that does not carry any risks.

MRE is also noninvasive, but healthcare professionals do not recommend this procedure for people:

Most other types of implants are safe during an MRI, but a person should talk with a doctor or radiographer about any implanted devices before undergoing the procedure.

Doctors grade liver stiffness according to one of the following four grades:

  • No scarring: There is no indication of liver scarring.
  • Mild scarring: This grade may be an indication of fatty liver disease, in which the liver contains more than 5–6% fat.
  • Moderate scarring: This grade indicates the presence of fibrosis.
  • Advanced scarring: This type indicates cirrhosis.

A 2015 review suggests that doctors can use liver elastography results not only to measure liver stiffness, but also to predict disease outcomes.

The ALF states that fibrosis is reversible if a person identifies and treats the condition in its early stages. Without treatment, fibrosis can develop into cirrhosis or liver cancer.

A liver elastography test is a procedure that doctors use to help diagnose and determine the extent of fibrosis. In fibrosis, the liver tissue becomes thickened and less flexible, impeding liver function.

Liver elastography involves passing low frequency vibrations through the liver and measuring the frequency of these vibrations to determine the thickness of liver tissue. There are two types of elastography tests: ultrasound and magnetic resonance. Both are noninvasive procedures that medical professionals designed to replace the traditional liver biopsy.

Doctors use liver elastography tests to help them diagnose and determine the severity of liver disease. They may also use them to guide treatments and predict how liver diseases may progress.