How is a FibroScan (Fibrosis Scan) done?

How FibroScan is Performed

FibroScan (vibration-controlled transient elastography) is performed by placing an ultrasound probe on the right upper abdomen through the intercostal space while the patient lies supine with their right arm maximally abducted, taking measurements at a depth of 1.5-2 cm below the liver capsule during brief breath-holding. 1

Patient Preparation

• Patients must fast for at least 4 hours before the examination, as food intake increases hepatic blood flow and can falsely elevate liver stiffness measurements 1
• The patient should lie supine (on their back) with the right arm raised in maximal abduction to widen the intercostal spaces 1
• For patients with alcohol-related liver disease, ideally perform the test after 2 weeks of abstinence, as recent alcohol consumption can falsely elevate results 2

Technical Procedure

• The ultrasound probe is positioned on the right upper abdomen over the right lobe of the liver through the intercostal space 1
• The operator selects a region of interest (ROI) that is free of blood vessels and bile ducts 1
• Measurements are taken at a depth of 1.5-2 cm below the liver capsule (avoiding measurements <1 cm depth due to reverberation artifacts) 1
• The patient briefly holds their breath during each measurement 1
• The device generates a mechanical vibration that creates shear waves, and measures liver stiffness by calculating the velocity of these shear waves through the liver tissue 1, 3
• The entire procedure takes approximately 5 minutes with immediate results 2, 4

Reliability Criteria

A FibroScan result is only considered reliable if it meets ALL three technical validity requirements: 2

• ≥10 successful measurements must be obtained 2, 4
• Success rate must be ≥60% 2, 4
• Interquartile range (IQR) must be <30% of the median value 2, 4

Measurement Depth Considerations

• Measurements can be made up to 7-8 cm from the probe, but to ensure reproducibility, maintain a consistent depth of 4-4.5 cm for all follow-up tests on the same patient 1
• Measuring at depths <1 cm below the liver capsule reduces reproducibility and diagnostic ability 1

Common Technical Limitations

• FibroScan may fail or produce unreliable results in patients with obesity (BMI >28 kg/m²), though an extra-large probe is now available for obese patients 1
• The test cannot be performed reliably in patients with ascites, narrow intercostal spaces, acute hepatitis, or extrahepatic biliary tract obstruction 1, 4
• Failure rates range from 1.1-3.5% in Asian populations and 4.3-10.5% in Western populations, primarily due to differences in body habitus 1
• During pregnancy, VCTE examination is not recommended due to changes in liver position 1

Result Interpretation

• Results are expressed in kilopascals (kPa), with higher values indicating greater liver stiffness and more advanced fibrosis 1
• The median value of the valid measurements is used as the final result 1
• Liver stiffness can be influenced not only by fibrosis but also by edema, inflammation, extrahepatic cholestasis, and passive congestion 1