Importance of fibro liver scan in clinical practice

Article by Dr Manasa S, B.A.M.S

FibroScan is an efficient and painless technique that uses ultrasound to examine the condition of the liver. It offers a non-invasive approach to gauge liver tissue stiffness commonly known as fibrosis. Its simplicity makes it an ideal tool for promptly evaluating liver damage during consultations and providing instant results. Furthermore, its non-invasive nature allows for repeated assessments over time, tracking changes in liver scarring or fat content in patients.

FibroScan technology guarantees precise evaluation of liver fibrosis stemming from different liver-damaging conditions such as excessive alcohol consumption, viral hepatitis, and non-alcoholic fatty liver disease.

What is the working principle of FibroScan device?

The Fibroscan device (Echosens) operates by utilizing shear wave velocity measurement. This involves transmitting a 50-MHz wave into the liver via a small transducer located at the end of an ultrasound probe. The probe is equipped with another transducer capable of gauging the velocity of the shear wave as it traverses through the liver, quantified in meters per second. Subsequently, the shear wave velocity is translated into liver stiffness, denoted in kilopascals. In essence, the technology assesses the velocity of the sound wave within the liver and then converts this data into a liver stiffness reading. This process is commonly known as liver ultrasonographic elastography.

Advantages of conventional Liver biopsy over FibroScan

Liver biopsy has been the traditional way to check how much scarring is there in the liver. It’s often used for people with certain liver infections like hepatitis B or C to see if treatment is needed. But there are downsides to biopsy: it’s a surgery, needs a hospital stay, costs a lot, and carries risks like pain and bleeding. Also, because it only looks at a tiny part of the liver, it might not give a full picture.

To avoid these problems, scientists have worked on non-surgical tests for liver scarring. One of these is Fibroscan, which has some advantages over biopsy. It is quick, painless, and doesn’t need sedation. Plus, it’s cheaper and doesn’t have side effects. Doctors get the results right away, so they can make decisions during the patient’s appointment.

Indications of FibroScan

– Autoimmune Hepatitis: A condition where the body’s immune system mistakenly attacks the liver cells, leading to inflammation and liver damage.

– Cirrhosis: A late stage of scarring (fibrosis) of the liver caused by many forms of liver diseases and conditions, such as hepatitis and chronic alcoholism, resulting in impaired liver function.

– Genetic Diseases (such as Hemochromatosis and Wilson’s Disease): Hereditary disorders that affect the liver’s ability to process certain substances, leading to the accumulation of toxic levels of metals like iron (hemochromatosis) or copper (Wilson’s disease) in the liver and other organs.

– Hepatitis B: A viral infection that causes inflammation of the liver, transmitted through contact with infected blood or body fluids, leading to acute or chronic liver disease.

– Hepatitis C: A viral infection causing liver inflammation, usually spread through contact with contaminated blood, leading to chronic liver disease and potentially liver cancer.

– Alcoholic Liver Disease: Liver damage caused by excessive alcohol consumption, ranging from fatty liver to more severe conditions like alcoholic hepatitis and cirrhosis.

– Non-Alcoholic Steatohepatitis (NASH): A type of non-alcoholic fatty liver disease (NAFLD) characterized by inflammation and liver cell damage, often associated with obesity, insulin resistance, and metabolic syndrome.

Procedure of FibroScan

– Arriving 15 minutes before the scheduled procedure time is planned.

– The presentation of one’s insurance / ID card and a list of the current medications is required.

– No sedation of any kind is needed for FibroScan.

– Driving oneself to and from the test is permissible.

– The procedure will be completed in about 5 minutes.

– The appointment will have a duration of approximately 30 minutes.

– For the procedure, the individual will be positioned on their back with right arm raised behind the head, and their right abdominal area is exposed (wearing loose fitting clothing is advised).

– A water-based gel will be applied to the skin, followed by the placement of a non-invasive probe over the liver by a medical provider.

– A slight vibration may be felt on the skin at the tip of the probe during the exam as it delivers ultrasound waves to measure the area.

– The information from the test will be analysed by the computer, and the results will be reviewed by the physician. Once reviewed, patients will be notified of the results.

Preparation for FibroScan

– Fasting for at least 3 hours before the liver fibrosis test is required, with consumption limited to only clear fluids during that time.

– Wearing comfortable, easily movable clothes (e.g., loose shirt, dress) is advised so as to allow examination of the right upper abdomen.

– Avoiding tight clothing is recommended.

– Resting on the examination bed for a few minutes before the exam may be necessary for accurate measurements.

 Actual Procedure

The procedure involves lying on one’s back with their right arm positioned above their head to provide access to the right rib cage for liver scanning.

– Gel is applied to the area, and the FibroScan device is placed on the skin between the ribs. One may feel a slight vibration as energy pulses are sent to the liver to collect measurements.

Duration of the procedure: Most often the FibroScan takes no longer than 10-20 minutes. It is done as outpatient procedure so that patients can go home after the completion of the procedure.

Results Turnaround Time:

-The score of the Fibroscan is recorded as a numerical score. The score is then interpreted and relevant understanding is made.

– Results can typically be expected within a few business days after the appointment.

Important terms used in FibroScan

– Fibrosis – also known as liver scarring, occurs when excessive connective tissue forms in the liver, affecting its function over time.

– Liver stiffness – indicates the degree of hardness in the liver, often associated with the presence of scarring.

– Fatty change – refers to the abnormal accumulation of fat within the liver cells, which can impair liver function and lead to various health issues.

– Steatosis – a condition characterized by an excessive accumulation of fat in the liver, can result from factors such as obesity, alcohol consumption, or certain medical conditions.

– CAP score – is a method used to quantify the percentage of fat accumulation within the liver, providing insights into the severity of steatosis and guiding treatment decisions.

Fibrosis and steatosis are measured separately from one another.

Interpretations of the FibroScan report

About the CAP score

CAP score is measured in decibels per meter [dB/m]. This score ranges from 100 dB/m to 400dB/m.

A score below 238dB/m indicates a normal liver.

About the Fibrosis Result

The stiffness or fibrosis is measured in kilopascals [kPa]. Levels between 2 and 7kPa indicate normal or mild scarring.

Fibrosis score – F0 TO F1 – No or mild scarring

Fibrosis score – F2 – Moderate liver scarring

Fibrosis score – F3 – Severe liver scarring

Fibrosis score – F4 – Advanced liver scarring

Limitations of the scan results

Certain conditions can affect the fibrosis results and they are as follows:

1. Conditions that cause increase in liver stiffness results

– Inflammation of the liver- Inflammation or swelling of the liver due to recent liver illness or prolonged consumption of alcohol might give a false result of increased liver stiffness result.

– Benign or cancerous tumour in the liver

– Congestion in the liver where there is accumulation of blood or fluid in the liver caused due to heart failure might give incorrect results

2. Conditions that give inaccurate results or no results

– Obesity is characterized by having a body mass index (BMI) exceeding 30, indicating an excessive and unhealthy accumulation of body fat, which can lead to various health complications such as cardiovascular disease and diabetes.

– Ascites refers to the accumulation of fluid in the abdominal cavity, often resulting from conditions like liver cirrhosis, heart failure, or certain cancers, causing abdominal swelling and discomfort.

– Biliary obstruction occurs when a blockage impedes the normal flow of bile from the liver into the intestine, potentially leading to jaundice, abdominal pain, and other symptoms associated with impaired liver function.

– Scar tissue, which can develop post-surgery or due to radiation therapy, forms as a result of the body’s healing process, but excessive buildup can lead to complications such as organ dysfunction or obstruction of normal physiological processes.

What are the benefits of FibroScan?

– Examination is completely painless

– Numerical result is instantly accessible

– Liver evaluation is proven to be effective

– Patient is able to leave immediately after procedure

– Procedure is remarkably easy to undergo

– No need for local or general anaesthesia.

Are there any risks involved in FibroScan?

FibroScan is easy, painless, and quick. It is a non-invasive procedure unlike biopsy, so there are no complications involved in this procedure.