Definition of magnetic resonance elastography
Magnetic resonance elastography (MRE) is a new way to image the body. It works by combining MRI imaging with sound waves to create a visual map (elastogram) showing the stiffness of body tissues.
MRE is used to detect hardening of the liver caused by many kinds of chronic liver disease. MRE also has potential as a noninvasive way to diagnose diseases in other parts of the body.
Why it’s done
MRE measures the stiffness of liver tissue in people with known or suspected liver disease. Liver disease can result in scarring of the liver (fibrosis), which increases the stiffness of liver tissue.
Often, people with liver fibrosis don’t experience any signs or symptoms. But untreated liver fibrosis may progress to cirrhosis, which can be fatal. If diagnosed, liver fibrosis often can be treated to halt progression and sometimes to reverse the condition.
Studies have shown that MRE is highly accurate at ruling out liver fibrosis. If you have liver fibrosis, MRE can help your doctor gauge the severity of your liver disease, guide treatment decisions and assess your response to treatment.
The traditional test for liver fibrosis uses a needle to extract a sample (biopsy) of liver tissue. MRE offers several advantages:
- It’s noninvasive and generally safer and more comfortable than biopsy is.
- It assesses the entire liver, not just the portion of liver tissue that is biopsied or imaged by other noninvasive tests.
- It can detect fibrosis at an earlier stage than can other imaging methods.
- It’s effective in people who are obese or who have fluid accumulation in the abdomen (ascites).
Risks of magnetic resonance elastography
The presence of metal in your body may be a safety hazard or affect a portion of the MRE image. Before receiving an MRE, tell the technologist if you have any metal or electronic devices in your body, such as:
- Metallic joint prostheses
- Artificial heart valves
- An implantable heart defibrillator
- A pacemaker
- Metal clips
- Cochlear implants
- A bullet, shrapnel or any other type of metal fragment
Before you schedule an MRE, tell your doctor if you think you’re pregnant. The effects of magnetic fields on fetuses aren’t well-understood. Your doctor may recommend choosing an alternative exam or postponing the MRE.
How you prepare for magnetic resonance elastography
Before an MRE exam, eat normally and continue to take your usual medications, unless otherwise instructed. You will be asked to change into a gown and to remove:
- Hearing aids
- Underwire bras
What you can expect
MRE is usually done as part of a conventional MRI examination. A standard MRI liver examination takes 30 to 45 minutes. The MRE portion of the test takes less than five minutes.
In MRE, a small pad is placed on the surface of your body. The pad emits low-frequency vibrations that pass through your liver. The speed at which the vibrations pass through the liver is measured. Vibrations travel faster through stiff tissue.
Results of magnetic resonance elastography
After the MRE procedure, a computer program creates a color-coded map showing the stiffness in your liver tissue.
A doctor specially trained to interpret MRE (radiologist) will analyze the images from your scan and report the findings to your doctor. Your doctor will discuss any important findings and next steps with you.