Elastography

What is elastography?

Elastography is a type of imaging test that checks your organs, especially the liver, to see if they are stiffer than normal. Stiff areas in your organs may be a sign of disease.

There are two types of elastography tests:

• Ultrasound elastography (also called transient elastography). In this test, an ultrasound device uses sound waves to send vibrations into a specific organ and measures how fast those vibrations move. If you have areas of stiff tissue, the vibrations will move faster through that area. A computer uses these measurements to make an image of any stiff areas in the organ the test was used on.
• MRE (magnetic resonance elastography). This test sends vibrations into an organ, usually 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. An MRE uses these images to make a map (also called an elastogram) of any stiff areas in a specific organ, such as the liver.

A newer type of elastography, called shear wave elastography, may also be used to check for stiffness in your organs. This newer type uses a more focused ultrasound wave (or pulse) to get a clearer image. It's especially useful when checking your muscles, joints, and bones.

Your health care provider may use elastography instead of a biopsy, which involves removing a piece of an organ's tissue for testing. This is because elastography can show signs of organ damage without using surgery.

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

What is it used for?

Elastography is mainly used to check for any stiffness in the liver. Stiff areas in the liver are a sign of scar tissue (fibrosis). Fibrosis happens when certain diseases, such as liver disease, damage the liver over time. When the liver tries to heal, it forms more scar tissue, which then:

• Replaces healthy liver cells
• Prevents your liver from working normally
• Reduces blood flow in your liver
• Causes more liver damage and fibrosis

If left untreated, fibrosis can become severe. This is called cirrhosis, a condition that:

• Permanently scars your liver
• Causes serious health problems such as liver failure
• Raises your risk of getting liver cancer

Elastography can help find liver scarring early, even if you don't have any symptoms of liver damage. If scarring is found early, your provider can start treatment before it becomes severe.

The information from an elastography test on the liver can help:

• Diagnose 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

Elastography may also be used to help diagnose conditions in other organs, such as the breasts, thyroid, and prostate. If your provider thinks you may have a condition that affects your muscles and bones, they may use shear wave elastography.

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 provider needs information to guide treatment choices
• Had other liver tests that show you may have inflammation or damage in your liver
• A condition that increases your risk for liver scarring and cirrhosis
• Signs or symptoms of cirrhosis

Conditions that can cause or increase your risk of liver damage include:

• Hepatitis B and hepatitis C. 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.
• Metabolic dysfunction-associated steatotic liver disease (MASLD). This used to be called nonalcoholic fatty liver disease (NAFLD). With this condition, fat builds up in your liver. It's most common in people who have diabetes, obesity, and/or high levels of cholesterol in their blood. It is not from drinking too much alcohol.
• Type 2 diabetes.
• Certain autoimmune diseases or genetic disorders, such as cystic fibrosis and autoimmune hepatitis.
• Long-term use of certain medicines, such as methotrexate.

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 right 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 to expose your abdomen (belly).
• 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 a specific organ. You may feel the device pulse against your skin, but it doesn't hurt.
• The vibrations will travel through a specific organ and "bounce" back to the device which sends the information to a computer.
• The computer makes an image of that organ showing any areas of stiff tissue and other signs of 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 a specific organ. 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 the organ your provider wants to see.
• The computer will make images of the specific organ that show any scarring and/or other signs of 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. You may also need to remove:

• Dentures
• Eyeglasses
• Wigs
• Hearing aids

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 a specific organ.

If an elastography test was used to check your liver, the results will tell 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 metabolic dysfunction-associated steatotic liver disease (also known as fatty liver disease), which may cause fibrosis.

If you have mild to severe fibrosis and/or metabolic dysfunction-associated steatotic 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.

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 in your abdomen (belly)

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

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