What is an elastography and what is it for?

Elastography is a technique used to diagnose possible diseases in the liver. Keep reading and know what it is and what its advantages and limitations are.

Last update: December 28, 2021

Elastography is a non-invasive diagnostic method for the detection of fibrosis in the liver. It is also known as liver elastography, MRI elastography or Fibroscan. Although it is appropriate to clarify that the latter is the commercial name of the device.

In relation to fibrosis, it is a process associated with chronic liver diseases. Hence the importance of evaluating its grade using elastography. This not only helps to obtain an accurate diagnosis, but establishes a prognosis.

In particular, in said procedure MRI technologies can be combined together with low frequency vibrations. This creates an image that shows whether there is stiffness (fibrosis) in the liver tissues.

What is and why is an elastography done?

There are various liver diseases (viral hepatitis, cholangitis, fatty liver, and more). In almost all of these conditions, fibrosis is a common process that can lead to long-term complications.

People with liver fibrosis usually don’t notice any particular symptoms.. However, if this process is not treated in time and properly, it can progress to become cirrhosis.

But if caught early, it can be treated and its progress halted. Therefore, various clinical examinations are performed in patients with liver disease in order to know the degree of fibrosis.

This includes tests, lab tests, and ultrasounds. Among them is elastography. The name has to do with the fact that the procedure allows to appreciate the elasticity of the liver.

This is a minimally invasive scanning technique. With it, a visual map is created that shows the stiffness and inflammation of the tissues, allowing the monitoring of the evolution of liver disease.

Liver fibrosis may progress to cirrhosis. That is why it is convenient to detect it in time.


When is elastography recommended?

Thanks to this technique, not only fibrosis is diagnosed, but also complications can be detected early, allowing to start treatment or change it. As mentioned, elastography is used for the diagnosis of fibrosis in various liver diseases:

  • Cirrhosis.
  • Hepatocarcinoma.
  • Viral hepatitis.
  • People with a history of alcoholism.

How is it the procedure?

There are two basic types of elastography:

  • Ultrasound: sound waves are used.
  • By magnetic resonance imaging (MRI): ultrasound is combined with magnetic resonance imaging.

Ultrasound

This form of liver elastography does not differ much from a conventional ultrasound. The procedure can be summarized in the following steps:

  1. The patient lies on his back on the stretcher.
  2. The skin of the abdomen is exposed, where a gel is spread.
  3. The device (transducer) is then placed on the right side of the abdominal area, a few inches below the last rib.
  4. This device will emit sound waves into the abdominal cavity.
  5. Although the waves cannot be perceived by the human ear, the person may feel a vibration or tingling, but without pain.
  6. The waves are reflected on a monitor.

Resonance elastography

This variant is done with the same device that is used in a conventional MRI. The procedure is also similar:

  1. The person lies on the stretcher.
  2. In this case, a pad is placed on the abdomen.
  3. The table slides into the MRI scanner.
  4. The pad vibrates.
  5. These signals are sent to a computer that records them and transforms them into a visual map.

In both procedures the degree of elasticity of the liver is shown, allowing to assess the rigidity or deformation that it presents. The stiffer the tissue, the greater the presence of fibrosis.



Preparation for elastography

Performing an elastography does not require any special preparations. In this sense, it is not considered necessary to suspend any medication. You only ask not to eat a few hours before, although you can drink water during that time.

On the other hand, if the elastography is by magnetic resonance, the person must remove any metallic accessories from their body, including glasses, hair clips, watches, jewelry and even dentures.

In patients with ascites drainage is required prior to elastography. Otherwise, the study cannot be carried out, since the accumulation of liquid interferes with the sound wave.

What do the results mean?

After several measurements in different areas of the liver, the information obtained with elastography is transformed into a final numerical value, calculated from the medians of the scores.

This will not only confirm or rule out the presence of fibrosis, but it will also allow a classification in degrees or levels to be established:

  • F0-F1: without fibrosis.
  • F2: mild.
  • F3: intermediate grade.
  • F4: advanced fibrosis or cirrhosis.

Of course, these results must correlate with what the patient’s medical history says. Also, additional testing may be required.

The form of elastography that uses magnetic resonance imaging does not differ much from conventional MRI.

Advantages of elastography

Elastography has several advantages over other procedures, since it is painless and non-invasive. It is less bloody, for example, than a liver biopsy.

What’s more, it is a simple and quick test. It does not take more than a few minutes. It also does not require any special preparation.

Most important of all, an elastography, in expert hands, makes it possible to diagnose liver disease with great precision, helping to guide medical decisions and determine treatment or response to it.

Limitations, risks and side effects

Elastography has certain limitations, as is the case in patients with ascites. The same happens in people with obesity, in whom the thickness of the subcutaneous cell tissue could also dampen the wave, preventing accurate measurement.

Usually, elastography does not usually generate any type of side effect in the patient. Some people may feel nervous, as with any medical exam; Even those who suffer from claustrophobia may experience anxiety about being inside the scanner.

The risks, on the other hand, are minimal. However, precautions should be taken in people with metal objects or devices on the body, such as prostheses, heart valves, pacemakers or cochlear implants.

Elastography at the service of liver treatment

Fibrosis affects blood flow in the liver, causing scar tissue to occur. If not treated promptly, it can lead to more serious and serious problems such as liver failure, cirrhosis, and cancer.

According to studies, liver-related diseases caused the death of 2.14 million people in the world in 2017. This means an increase of 11.4% in 5 years.

Fortunately, there are techniques such as elastography, which help in the diagnosis. If fibrosis is detected when it is mild, treatment can be started early, with a high chance of a positive prognosis.

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