Elastography

What is elastography?

Elastography is a type of imaging test that checks your organs to see if they are stiffer than normal. Stiff areas in your organs may be a sign of disease. Elastography is mainly used to check the liver for stiffness. Stiff areas in the liver are a sign of scar tissue (fibrosis) caused by liver disease.

Liver fibrosis happens when certain diseases damage the liver over time. When the liver tries to heal, it forms more scar tissue. Many conditions that cause ongoing or repeated liver damage can lead to liver fibrosis. Conditions that commonly cause fibrosis include:

• Hepatitis C and Hepatitis B. These liver diseases are caused by viruses.
• Alcohol use disorder (AUD). AUD can cause alcohol-associated liver disease, which includes the buildup of too much fat in the liver. The fat can cause liver inflammation (swelling) which damages liver tissue.
• Nonalcoholic fatty liver disease (NAFLD). This type of fat buildup often happens in people who have diabetes, obesity, and/or high levels of cholesterol in their blood. It is not from drinking too much alcohol.

As fibrosis develops, scar tissue replaces healthy liver cells and prevents your liver from working normally. The scar tissue can reduce blood flow in your liver. The lack of blood causes more liver damage and more fibrosis.

Without treatment, fibrosis can become severe. Severe fibrosis is called cirrhosis. With cirrhosis, liver scarring is permanent. It can cause serious health problems, including liver failure. Cirrhosis also increases your chance of getting liver cancer.

Fibrosis and early cirrhosis don't always cause symptoms. But elastography can help find liver scarring early, so treatment can start before the damage becomes severe. There are two types of liver elastography tests:

• Ultrasound elastography is also called transient elastography. An ultrasound device uses sound waves to send vibrations into your liver. The device measures how fast the vibrations move through your liver. If you have areas of stiff liver tissue, the vibrations will move faster through that area. A computer uses the measurements to make an image that shows any stiffness in your liver tissue, which is a sign of fibrosis.
• MRE (magnetic resonance elastography) sends vibrations into your liver that are measured with magnetic resonance imaging (MRI). MRI is a procedure that uses powerful magnets and radio waves to create images of organs and structures inside the body. In an MRE test, a computer program makes a map that shows any stiff areas of your liver.

Other names: liver elastography, transient elastography, FibroScan, MR elastography

What is it used for?

Liver elastography is used to check for liver fibrosis (scarring). It may be used instead of a liver biopsy, which involves removing a piece of liver tissue for testing.

The information from an elastography test can help:

• Diagnose liver conditions in people who have a high risk for liver disease
• Show how serious liver disease is
• Guide treatment choices for liver disease
• Monitor how well treatment for liver disease is working
• Help predict the chance that liver disease will cause certain serious problems
• Check how much fat is in the liver

Why do I need an elastography test?

You may need an elastography test to check for liver fibrosis (scarring) if you:

• Have liver disease and your health care provider needs information to guide treatment choices.
• Have had other liver tests that show you may have inflammation or damage in your liver.
• Are more likely to develop cirrhosis (severe liver scarring). Conditions that increase your risk for cirrhosis include:
  • Alcohol use disorder (AUD)
  • Type 2 diabetes
  • Chronic (long-lasting) hepatitis B or C
  • Certain autoimmune diseases or genetic disorders
  • Long-term use of certain medicines
• Have signs or symptoms of cirrhosis.

Cirrhosis may not cause symptoms until your liver is badly damaged. Symptoms of early cirrhosis may include:

• Feeling tired or weak
• Having a poor appetite
• Losing weight without trying
• Nausea and vomiting
• Mild pain in the upper ride side of your abdomen (belly)

As your liver condition gets worse, you may have other symptoms, including:

• Bruising and bleeding easily
• Confusion, memory loss, or sleep disorders
• Swelling in your legs or feet
• Bloating or full feeling in your abdomen from fluid buildup
• Itchy skin
• Dark urine (pee)
• Jaundice (a condition that causes your skin and eyes to turn yellow)

What happens during an elastography test?

An ultrasound elastography is often done by a radiology technician, who is a health care professional trained to do imaging tests. Sometimes a radiologist does the test. A radiologist is a doctor who specializes in using medical imaging tests to diagnose medical conditions.

An elastography test is quick and usually includes these steps:

• You'll remove clothing covering your right abdomen (belly) to expose the skin over your liver.
• You'll lie on a table and the technician will spread a special gel on your skin.
• The technician will hold a wand-like device, called a transducer, and move it across your skin.
• You'll hold your breath for 10 to 15 seconds while the device sends a series of vibrations into your liver. You may feel the device pulse against your skin, but it doesn't hurt.
• The vibrations will travel through your liver and "bounce" back to the device which sends the information to a computer.
• The computer makes an image of your liver showing any areas of stiff tissue and other signs of liver disease.

MRE (magnetic resonance elastography) is done with an MRI (magnetic resonance imaging) machine. During an MRE procedure:

• You'll lie on a narrow exam table.
• The technician will place some small devices on your lower right abdomen. One device, called a "driver," will send painless vibrations into your liver. The other devices send and receive radio waves to a computer.
• The table will slide into a large tunnel-like MRI machine. You will hear loud noises as the machine takes pictures. You may be given earplugs or headphones to block the noise.
• Inside the MRI, you'll be asked to hold your breath for 10 to 15 seconds when the vibrations are going through your liver.
• The computer will make images of your liver that show any scarring and/or other signs of liver disease.

Will I need to do anything to prepare for the test?

Your provider will tell you how to prepare for a liver elastography. In general, it's best to wear a loose-fitting shirt or sweater that you can easily pull up. You may be told to fast (not eat or drink) for several hours before your test.

If you're having an MRE, you'll need to remove all metal from your body. If you have any medical devices or metal inside your body let your provider know. The scanner can heat metal and cause burns.

Are there any risks to the test?

There are no known risks to having an ultrasound elastography. There is little risk to having an MRE for most people. If being inside a small space makes you nervous, tell your provider before your test. Your provider may give you medicine to help you relax. If you are or could be pregnant, let your provider know.

What do the results mean?

Your elastography images will be studied by a radiologist, who will send your results to your provider. Your results will show how much stiffness was found in your liver. This tells you how much liver scarring (fibrosis) you have. Your results will be given a fibrosis score which is based on the amount of stiffness in your liver and the cause:

• F0 to F1 is normal, which means you have little or no scarring in your liver.
• F2 means you have moderate scarring.
• F3 means you have severe scarring.
• F4 means you have cirrhosis (very severe scarring).

Your results also show how much fat buildup you have in your liver. The measurement of fat in your liver is called a "CAP score." It tells you the percentage of your liver that is fat. The amount of fat in a normal liver is 5% or less. Higher amounts mean you have fatty liver disease, which may cause fibrosis.

If you have mild to severe fibrosis and/or fatty liver disease, your condition can improve if you treat the cause and make lifestyle changes, including diet and exercise. If you have cirrhosis, treating the cause may keep liver scarring from getting worse. Successful treatment may slowly improve some of the scarring.

If you have questions about your results, talk with your provider.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about an elastography?

Certain conditions can affect the accuracy of an elastography test. These include:

• Liver inflammation (swelling) from an illness or drinking alcohol
• Tumors in your liver
• Obesity
• Abnormal fluid buildup your abdomen (belly)