Elastography 101: How this test helps diagnose liver disease

Elastography is an imaging test to check the elasticity of tissue in your body. Stiffness in your tissue is often a sign of disease. Elastography is often used to check for disease in the liver.

Here, I’ll explain more about elastography, including the different types, how it helps detect liver disease and what happens during the procedure. 

What is elastography?

Elastography is a non-invasive test that measures tissue stiffness and elasticity in your body’s organs and structures. It is most often used to assess the liver, a test that is sometimes called liver elastography. If you have increased tissue stiffness in your liver, it may be a sign of disease.

Elastography can also be used to help diagnose:

• Thyroid nodules
• Breast lesions
• Conditions in the tendons

How does elastography help diagnose liver disease?

If elastography detects a lot of stiffness in your liver, it is usually a sign of liver fibrosis. Liver fibrosis is a buildup of scar tissue that, if left untreated, can progress to chronic liver disease like cirrhosis. Cirrhosis of the liver is the leading cause of hepatocellular carcinoma, the most common type of liver cancer.

Common causes of liver fibrosis include:

• Hepatitis B and Hepatitis C: Hepatitis B is a virus that spreads through infected blood, semen and other bodily fluids. Hepatitis C is a virus that spreads through infected blood.
• Alcoholic-associated liver disease (ALD): This develops from long-term, heavy alcohol use. ALD causes a buildup of fat in your liver, which leads to inflammation.
• Fatty liver disease: This condition, also known as metabolic dysfunction-associated steatotic liver disease (MASLD), is a buildup of fat in the liver. It is more common in people who have obesity, type 2 diabetes, high cholesterol levels in the blood and metabolic syndrome. It is not caused by drinking alcohol. Elastography does not detect fatty liver disease, per se, but when combined with an ultrasound or MRI, it does provide an overall assessment of the liver. So, both ultrasound and MRI are able to measure fat deposits and fibrosis. 

Your doctor might order an ultrasound or MRI elastography if you have abnormal liver function tests that suggest underlying liver disease. Or your doctor may want to see the extent of liver disease. For instance, if you have a fatty liver, they may want to see if you have fibrosis as well. This can help guide your treatment.  

What are the types of elastography?

There are two main types of elastography.

Ultrasound elastography

This type combines elastography with an ultrasound. Your radiologist may use different techniques to perform ultrasound elastography.

Point shear wave elastography: This technique measures the stiffness of your liver tissue in a specific location. The technology is built into the ultrasound machine, which delivers pulses into your tissue that create shear waves. The faster the shear waves travel through the tissue, the stiffer the tissue.

2D shear wave elastography: This technique works like point shear wave elastography. The difference is that instead of a single location, 2D shear wave elastography can measure stiffness across a larger area of tissue by creating a detailed 2D image.

Transient elastography (FibroScan®): Your doctor uses a handheld device called a transducer on your skin to send vibrations to your liver. The faster the vibrations move through the tissue, the stiffer the tissue.  

Magnetic Resonance Elastography (MRE)

This type of elastography is a test that is often combined with a standard MRI to measure how stiff your liver is.

During this test, your radiologist will place a little paddle on your skin covering your liver. This will create gentle vibrations that travel through the liver. The MRI will use magnets and radio waves to take detailed images and produce an elastogram that tracks how the waves move through your tissue. If the waves don’t move easily, the tissue is stiff.

Which test is right for me? 

Your healthcare provider will determine which type of elastography is right for you based on several factors, such as your weight, overall health, whether you’ve had previous surgeries and your personal preference.

How should I prepare for elastography?

Usually, you will need to fast for at least four to six hours before the test. This is because eating foods – especially those high in fat or sugar – can increase the stiffness in your liver tissue. This can affect the results of your elastography.

Let your doctor know if you have any medical devices, such as a pacemaker, or any metal in your body. These can affect MRE results, so your provider may recommend a different type of elastography for you.  

Your radiologist will provide detailed instructions on how to prepare for elastography.

Is elastography painful?

No. Elastography is a non-invasive test that is well tolerated by patients. There are no needles involved, and you should not feel any pain or discomfort.

How long does elastography take?

The time it takes to complete an elastography depends on the type of test you get.

In general, ultrasound elastography takes about 20 minutes. An MRE by itself takes about 15 to 20 minutes, but if you get one with an MRI, it could take an additional 15 to 30 minutes. Keep in mind, times may vary depending on the doctor or hospital that performs yours. In some cases, it may take longer.

What do my elastography results mean?

Your radiologist will read the shear wave elastography images or the MR elastogram, which are visual maps of your tissue stiffness, with results reported in terms of velocity in m/s or kilopascals for ultrasound elastography, and kilopascals for MREs.

The good news is you won’t have to worry about these specific metrics. The radiologist will analyze the test results and share a report with your doctor who ordered the elastography. Then, your doctor will go over the results with you. Your results will typically include your liver’s stiffness level and a fibrosis score – which measures how much scarring is present in your liver.

Here are possible results of a fibrosis score:

• F0 to F1: Your liver is normal, with minimal or no scarring.
• F2: There is moderate scarring in your liver.
• F3: There is severe scarring in your liver.
• F4: The scarring in your liver is very severe, which indicates cirrhosis.

If you have ultrasound elastography, your results will also include whether there is suspicion of compensated advanced chronic liver disease (cACLD). This is a stage of severe liver fibrosis or cirrhosis that may not have any symptoms.

Results may be:

• Normal or high probability of normal: You likely don’t have compensated advanced chronic liver disease.
• Suggestive of cACLD: There is a suspicion of compensated advanced chronic liver disease, but you may need other tests like a liver biopsy to confirm.
• Highly suggestive of cACLD: It is highly likely that you have advanced fibrosis or cirrhosis and need further evaluation.

It’s important for doctors to catch compensated advanced chronic liver disease early before it progresses to decompensated advanced chronic liver disease (DACLD). This is an irreversible stage when cirrhosis becomes life-threatening. Symptoms can include ascites, gastrointestinal bleeding, jaundice and brain dysfunction.

Diagnosing cACLD can allow the doctor to intervene and treat the liver disease, so that it regresses back into the normal range. 

How accurate is liver elastography?

Liver elastography is an accurate non-invasive way to measure the stiffness of tissue in your liver. This can be done to diagnose liver fibrosis. Your doctor also may order a liver elastography to assess whether the fibrosis gets better after treatment, or if the disease progresses.

Some things may affect the results of your liver elastography. These include:

• Eating foods high in fat or sugar before the test
• Having obesity
• Inflammation in the liver
• Having a lot of iron in your liver or metal from prior surgeries, such as cholecystectomy clips

In some cases, other diagnostic tests, such as a liver biopsy, may be recommended.

What are my treatment options after an elastography?

Chronic liver disease is treatable in its early stages and can often be reversed.

Treatment often depends on the cause of liver disease. If you have hepatitis, doctors can prescribe antiviral medications to decrease the viral load on your liver. Diet and lifestyle changes are often recommended to treat fatty liver disease. These changes may include getting more exercise and eating a healthy diet with less fats. If you have alcohol-associated liver disease, eliminating alcohol removes the toxin that is damaging your liver. 

Once the fibrosis in your liver is severe (cirrhosis), the scarring cannot be undone. Your doctor will discuss treatment options to stop or slow further damage to the liver.

Tests like elastography are important to help doctors find liver disease early. They’re able to reverse the damage to the liver and cure the disease.      

Leonardo Marcal, M.D., is an abdominal imaging specialist at UT MD Anderson.

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