What can cause artificially elevated transient elastography (TE) results?

Causes of Artificially Elevated Transient Elastography Results

Several conditions can cause artificially elevated transient elastography (TE) results that do not reflect the true degree of liver fibrosis, including acute inflammation, extrahepatic cholestasis, liver congestion, recent food intake, and amyloid deposition.

Primary Factors That Artificially Elevate Liver Stiffness Measurements

1. Acute Inflammation

• Active hepatitis with elevated liver enzymes (particularly AST >100 U/L) can significantly increase liver stiffness independent of fibrosis 1
• Inflammatory activity causes edema and increased pressure within the liver parenchyma

2. Extrahepatic Cholestasis

• Bile duct obstruction causes increased pressure within the liver, falsely elevating stiffness measurements 1
• Should be ruled out with imaging and laboratory tests before interpreting TE results

3. Vascular Congestion

• Heart failure and venous congestion significantly increase liver stiffness 1, 2
• Fontan circulation patients show elevated liver stiffness measurements correlating with higher venous pressures 3
• Any condition causing hepatic vein congestion will affect measurements

4. Recent Food Intake

• Non-fasting state increases hepatic blood flow, leading to higher stiffness values 1
• Patients should fast for at least 4 hours before TE examination 1

5. Alcohol Consumption

• Recent alcohol intake can modify liver stiffness measurements 1
• Abstinence may decrease values while relapse can increase them

Other Important Confounding Factors

1. Amyloid Deposition

• Hepatic amyloidosis can cause very high stiffness values in the absence of fibrosis 4
• Amyloid deposits increase liver parenchyma rigidity independent of fibrosis

2. Technical and Patient-Related Factors

• Obesity (BMI >28 kg/m²) can lead to unreliable results with standard M probe 1
• Narrow intercostal spaces may impede proper probe positioning 1
• Measurements taken too close to the liver capsule (<1 cm) may be unreliable 1
• Ascites was traditionally considered a limitation but may be overcome with XL probe 5

Recommendations for Accurate Measurement

1. Ensure patient is fasting for at least 4 hours before examination
2. Check for active inflammation (liver enzymes) before interpreting results
3. Review cardiac function and rule out heart failure
4. Exclude extrahepatic cholestasis with imaging/laboratory tests
5. Maintain consistent measurement depth (ideally 1.5-2 cm below liver capsule)
6. Consider using XL probe for obese patients
7. Interpret results in clinical context with laboratory and imaging findings

Quality Criteria for Reliable Results

• Obtain at least 10 valid measurements
• Success rate >60% (ratio of valid shots to total shots)
• Interquartile range (IQR) less than 30% of the median value (IQR/M <0.30)

Remember that TE results should always be interpreted in the context of clinical, imaging, and laboratory findings, as recommended by the EASL clinical practice guidelines 1. When TE results are inconsistent with clinical presentation, liver biopsy may be necessary for accurate assessment.