What is Magnetic Resonance Elastography? Purpose, Levels/Procedure & Results

Magnetic resonance elastography (MRE) is a specialized imaging test that measures how stiff or soft your organs are, particularly your liver. Think of it as a gentle way to "feel" your organs from the outside, similar to how a doctor might press on your abdomen during a physical exam, but much more precise and detailed.

This non-invasive test combines regular MRI imaging with sound waves to create detailed maps of tissue stiffness. The information helps doctors detect scarring, inflammation, or other changes in your organs that might not show up on standard imaging tests.

What is Magnetic Resonance Elastography?

MRE is an advanced imaging technique that uses magnetic fields and sound waves to measure tissue elasticity. The test works by sending gentle vibrations through your body while you're inside an MRI machine, then capturing how these waves move through your organs.

When tissues are healthy, they tend to be soft and flexible. However, when scarring or fibrosis develops, tissues become stiffer and less elastic. MRE can detect these changes even in early stages, often before other tests show abnormalities.

The test is most commonly used to evaluate liver health, but it can also assess other organs like the brain, heart, kidneys, and muscles. This makes it a valuable tool for diagnosing various conditions without needing invasive procedures.

Why is Magnetic Resonance Elastography done?

Your doctor might recommend MRE to evaluate organ stiffness and detect disease progression. The test is particularly useful for monitoring liver conditions, as it can identify scarring (fibrosis) that develops from various liver diseases.

The most common reasons for MRE include assessing chronic liver conditions like hepatitis, fatty liver disease, or cirrhosis. It helps doctors determine how much scarring has occurred and whether treatments are working effectively.

Beyond liver evaluation, MRE can help diagnose brain conditions, heart problems, and muscle disorders. Here are the main conditions where MRE provides valuable information:

• Chronic hepatitis B or C
• Non-alcoholic fatty liver disease (NAFLD)
• Alcoholic liver disease
• Primary biliary cholangitis
• Autoimmune hepatitis
• Brain tumors or neurological conditions
• Heart muscle stiffness
• Kidney fibrosis
• Muscle disorders

In some cases, doctors use MRE to monitor treatment response or plan surgical procedures. The test can also help avoid more invasive procedures like liver biopsies in certain situations.

What is the procedure for Magnetic Resonance Elastography?

The MRE procedure is similar to a regular MRI scan with one key difference: a special device generates gentle vibrations during the imaging. You'll lie on a table that slides into the MRI machine, and the entire process typically takes 45 to 60 minutes.

Before the scan begins, a technologist will place a small, soft pad called a "passive driver" on your body over the area being examined. This pad connects to a machine that creates low-frequency sound waves, similar to a very gentle massage.

During the scan, you'll hear the normal MRI sounds plus a gentle drumming or tapping sensation from the vibrations. The vibrations are completely painless and feel like a light rhythmic pressure on your skin.

Here's what happens during your MRE procedure:

1. You'll change into a hospital gown and remove any metal objects
2. The technologist positions you on the MRI table
3. A passive driver pad is placed on your body
4. You'll receive earplugs or headphones to reduce noise
5. The table slides into the MRI machine
6. Gentle vibrations begin while images are captured
7. You'll need to hold your breath for short periods (10-20 seconds)
8. The entire process is completed in about 45-60 minutes

Throughout the procedure, you can communicate with the technologist through an intercom system. If you feel uncomfortable at any point, you can ask to stop or take a break.

How to prepare for your Magnetic Resonance Elastography?

Preparing for MRE is straightforward and similar to preparing for a regular MRI. You'll need to avoid eating for 4-6 hours before the test if you're having liver imaging, as this helps provide clearer images.

The most important preparation involves checking for any metal objects in your body. Since MRE uses powerful magnets, certain metals can be dangerous or interfere with the test results.

Before your appointment, make sure to inform your healthcare team about any of these items:

• Pacemakers or defibrillators
• Cochlear implants
• Metal joint replacements
• Surgical clips or staples
• Intrauterine devices (IUDs)
• Tattoos with metallic ink
• Permanent makeup
• Body piercings

On the day of your test, wear comfortable, loose-fitting clothing without metal fasteners. You'll likely change into a hospital gown, but comfortable clothes make the experience more pleasant.

If you have claustrophobia or anxiety about enclosed spaces, talk to your doctor beforehand. They might prescribe a mild sedative to help you relax during the procedure.

How to read your Magnetic Resonance Elastography results?

MRE results are measured in kilopascals (kPa), which indicates tissue stiffness. Normal, healthy tissue typically measures between 2-3 kPa, while stiffer, scarred tissue shows higher values.

Your doctor will interpret these measurements alongside your medical history and other test results. The specific ranges can vary depending on which organ was examined and the imaging technique used.

For liver MRE, here's what different stiffness values generally indicate:

• Normal liver: 2.0-3.0 kPa
• Mild fibrosis: 3.0-4.0 kPa
• Moderate fibrosis: 4.0-5.0 kPa
• Severe fibrosis: 5.0-6.0 kPa
• Cirrhosis: Above 6.0 kPa

It's important to remember that these are general guidelines, and your doctor will consider your individual situation when interpreting results. Some conditions can cause temporary stiffness that doesn't necessarily indicate permanent damage.

The results also include detailed images showing stiffness patterns throughout the examined organ. This spatial information helps doctors identify specific areas of concern and plan appropriate treatments.

What is the best Magnetic Resonance Elastography level?

The "best" MRE level depends on the organ being examined and your individual health situation. For liver health, lower stiffness values generally indicate healthier tissue with less scarring or inflammation.

A normal liver MRE reading falls between 2.0-3.0 kPa, suggesting healthy, flexible tissue. Values in this range typically indicate minimal fibrosis and good liver function.

However, what's considered optimal can vary based on your age, underlying conditions, and other factors. Some people naturally have slightly higher baseline stiffness due to genetics or previous illnesses that have resolved.

Your doctor will determine your target range based on your specific circumstances. The goal is often to maintain stable readings or see improvement over time, rather than achieving a specific number.

What are the risk factors for abnormal Magnetic Resonance Elastography results?

Several factors can contribute to increased organ stiffness detected by MRE. Understanding these risk factors helps explain why your doctor might recommend this test and what the results might mean.

The most significant risk factors relate to conditions that cause inflammation or scarring in organs over time. These processes gradually make tissues stiffer and less flexible.

Common risk factors that may lead to abnormal MRE results include:

• Chronic viral hepatitis (B or C)
• Excessive alcohol consumption
• Obesity and metabolic syndrome
• Diabetes
• High cholesterol levels
• Autoimmune conditions
• Certain medications
• Genetic liver diseases
• Previous organ infections

Age can also play a role, as organs naturally become slightly stiffer over time. However, significant stiffness usually indicates an underlying condition rather than normal aging.

Some rare conditions can also affect MRE results, including Wilson's disease, hemochromatosis, and alpha-1 antitrypsin deficiency. These genetic conditions cause specific types of organ damage that show up as increased stiffness.

What are the possible complications of abnormal MRE results?

Abnormal MRE results themselves don't cause complications, but they may indicate underlying conditions that can lead to serious health problems if left untreated. The complications depend on which organ shows increased stiffness and the underlying cause.

For liver-related abnormalities, the main concern is progression to cirrhosis and liver failure. When liver tissue becomes increasingly stiff due to scarring, it can't perform its essential functions effectively.

Potential complications of liver stiffness detected by MRE include:

• Portal hypertension (increased pressure in liver blood vessels)
• Varices (enlarged veins that can bleed)
• Ascites (fluid accumulation in the abdomen)
• Hepatic encephalopathy (brain dysfunction due to liver problems)
• Increased risk of liver cancer
• Complete liver failure requiring transplantation

In other organs, abnormal stiffness can lead to different complications. Brain tissue stiffness might indicate tumors or neurodegenerative diseases, while heart muscle stiffness can affect pumping function.

The good news is that early detection through MRE often allows for intervention before these complications develop. Many conditions that cause organ stiffness can be treated or managed effectively when caught early.

When should I see a doctor for Magnetic Resonance Elastography follow-up?

You should schedule follow-up appointments based on your MRE results and your doctor's recommendations. The timing depends on whether abnormalities were found and how quickly your condition might progress.

If your MRE results are normal, your doctor might recommend repeat testing in 1-2 years, especially if you have risk factors for organ disease. Regular monitoring helps catch changes early before they become serious.

For abnormal results, you'll likely need more frequent follow-up appointments. Your doctor will create a monitoring schedule based on the severity of your condition and how quickly it might change.

You should contact your doctor sooner if you develop new symptoms, regardless of your MRE results:

• Persistent abdominal pain or swelling
• Unexplained fatigue or weakness
• Yellowing of skin or eyes (jaundice)
• Dark urine or pale stools
• Nausea or loss of appetite
• Easy bruising or bleeding
• Confusion or difficulty concentrating

Don't wait for your next scheduled appointment if you're experiencing concerning symptoms. Early intervention can make a significant difference in treatment outcomes.