FibroScan® (VCTE): Principles, Performance, Probes, CAP, and Clinical Use in MASLD
Introduction
FibroScan® (Echosens, Paris, France) represents the world’s first commercial device dedicated to liver stiffness measurement using vibration-controlled transient elastography (VCTE). Since its introduction in 2003, it has become the most extensively validated and widely referenced non-invasive tool for liver fibrosis assessment, with over 5,300 peer-reviewed publications and more than 218 international guideline recommendations (Echosens, 2022).
The Baveno VII consensus specifically states that “LSM by TE is presented as the cornerstone NIT for both better risk stratification and improved clinical decision making for patients at risk of cACLD, CSPH and esophageal varices” (de Franchis et al., 2022). This endorsement reflects two decades of clinical validation establishing FibroScan as the reference standard for non-invasive liver assessment.
This article provides a comprehensive guide to FibroScan technology, including how VCTE works, the different device models and probes, the Controlled Attenuation Parameter (CAP) for steatosis assessment, diagnostic performance across liver disease etiologies, quality criteria, and clinical applications in MASLD and beyond.
This is Article 2 in a three-part series. Article 1 covers the fundamental principles of liver elastography. Article 3 covers ultrasound-based alternatives (pSWE and 2D-SWE).
1. How FibroScan Works: VCTE Technology
1.1 The VCTE Principle
FibroScan operates by inducing a mild mechanical vibration (50 Hz) through a probe placed on the patient’s right intercostal space. This vibration generates a shear wave that propagates through the liver parenchyma. An ultrasound transducer embedded in the same probe tracks the shear wave velocity, which is then converted to liver stiffness expressed in kilopascals (kPa) using Young’s modulus equation (Sandrin et al., 2003).
The device measures stiffness in a cylindrical volume approximately 1 cm wide and 4 cm long, positioned 2.5–6.5 cm below the skin surface (depending on probe type). This standardized sampling region ensures consistent measurements across examinations and centers.
1.2 What Makes VCTE Unique
Unlike ultrasound-integrated elastography methods (pSWE, 2D-SWE), FibroScan is a dedicated liver assessment device. It provides no B-mode anatomical imaging—its sole function is measuring liver stiffness and steatosis. This focused design offers several implications:
Advantages of dedicated design: - Highly standardized measurements - Simplified operator training - Consistent results across devices worldwide - Optimized for liver-specific assessment
Trade-offs: - Cannot visualize focal liver lesions - Cannot serve as a general hepatic ultrasound - Patients may still require conventional imaging
1.3 Simultaneous Steatosis Assessment
In addition to liver stiffness measurement (LSM), FibroScan simultaneously measures the Controlled Attenuation Parameter (CAP), which quantifies ultrasound attenuation as a surrogate for hepatic fat content. This dual assessment—fibrosis and steatosis in a single examination—is unique to the FibroScan platform and particularly valuable in MASLD evaluation (Sasso et al., 2012).
2. FibroScan Device Models
Echosens has developed several FibroScan models to address different clinical settings and requirements. All models measure liver stiffness using identical VCTE technology, ensuring comparable results regardless of device generation.
2.1 FibroScan 430 Mini+
The FibroScan 430 Mini+ represents the ultra-portable option in the product line:
| Specification | Detail |
|---|---|
| Display | 12.1-inch touchscreen |
| Weight | Approximately 5 kg |
| Probes | Compatible with S+, M+, and XL+ probes |
| Features | CAP measurement, battery-powered operation |
| Applications | Community screening, mobile clinics, point-of-care settings |
The 430 Mini+ delivers equivalent LSM accuracy to larger models, making it ideal for screening programs, primary care offices, and resource-limited settings where portability is essential.
2.2 FibroScan 530 Compact
The FibroScan 530 Compact is designed for liver clinic and point-of-care settings:
| Specification | Detail |
|---|---|
| Display | 15-inch interactive touchscreen |
| Weight | Approximately 10 kg with optional roll stand |
| Probes | S+, M+, and XL+ probes; dual probe connectors |
| Features | CAP measurement, Continuous CAP (CAPc) option, Automated Probe Selection (APS) tool |
| Applications | Hepatology clinics, endocrinology practices, primary care |
The 530 Compact offers the optimal balance between portability and full functionality, with dual probe connectors allowing rapid switching between M+ and XL+ probes without cable changes.
2.3 FibroScan 630 Expert
The FibroScan 630 Expert represents the most advanced model with additional capabilities:
| Specification | Detail |
|---|---|
| Display | 19-inch touchscreen |
| Weight | Approximately 15 kg (cart-based) |
| Probes | S+, M+, and XL+ probes; dual probe connectors |
| Unique Features | Spleen stiffness measurement (SSM) at 100 Hz, SmartExam technology |
| Applications | Tertiary referral centers, advanced portal hypertension assessment |
The 630 Expert’s spleen stiffness measurement capability enables non-invasive assessment of portal hypertension per Baveno VII criteria. SSM <21 kPa can rule out clinically significant portal hypertension (CSPH) in viral hepatitis, while SSM >50 kPa can rule in CSPH (de Franchis et al., 2022).
2.4 Model Comparison
| Feature | 430 Mini+ | 530 Compact | 630 Expert |
|---|---|---|---|
| Screen Size | 12.1” | 15” | 19” |
| Weight | ~5 kg | ~10 kg | ~15 kg |
| LSM (50 Hz) | ✓ | ✓ | ✓ |
| CAP | ✓ | ✓ | ✓ |
| SSM (100 Hz) | ✗ | ✗ | ✓ |
| SmartExam | ✗ | Option | ✓ |
| Probe Connectors | 1 | 2 | 2 |
| Portability | Highest | Moderate | Cart-based |
3. FibroScan Probes: Selection and Clinical Impact
FibroScan employs three specialized probes, each optimized for different patient morphologies. Correct probe selection is critical for accurate results—using the wrong probe can lead to significant diagnostic errors.
3.1 S+ Probe (Small/Pediatric)
| Parameter | Specification |
|---|---|
| Frequency | 5 MHz (higher frequency for superficial penetration) |
| Measurement Depth | 15–50 mm from skin surface |
| Indications | Pediatric patients; very thin adults (thoracic circumference ≤75 cm) |
| CAP | Available on newer S+ probes via CAPc algorithm |
The S+ probe was originally developed for children. Adult validation studies remain limited, though it may be appropriate for very thin adults where the M+ probe measures too deeply (Stadlbauer et al., 2021).
3.2 M+ Probe (Standard)
| Parameter | Specification |
|---|---|
| Frequency | 3.5 MHz |
| Measurement Depth | 25–65 mm from skin surface |
| Indications | Standard adult patients; skin-to-liver capsule distance (SCD) <25 mm; BMI typically <30 kg/m² |
| CAP | Available |
The M+ probe is the default for most adult examinations and has been validated in the majority of clinical studies. Most published cut-off values were derived using the M probe.
3.3 XL+ Probe (Extended)
| Parameter | Specification |
|---|---|
| Frequency | 2.5 MHz (lower frequency for deeper penetration) |
| Measurement Depth | 35–75 mm from skin surface |
| Indications | Overweight and obese patients; SCD ≥25 mm; BMI typically ≥30 kg/m² (particularly ≥32 kg/m²) |
| CAP | Available |
The XL probe was developed specifically for patients with increased subcutaneous adipose tissue. In the validation study by Myers et al. (2012), the XL probe reduced measurement failure from 16% (M probe) to 1% in overweight/obese patients.
Important technical note: The XL probe generates approximately 20% lower stiffness values than the M probe in the same patient. This systematic difference means dedicated XL probe cut-offs may be required for accurate staging (Durango et al., 2013).
3.4 Probe Selection Criteria
The study by de Lédinghen et al. (2019) established evidence-based criteria for probe selection:
Primary criterion: Skin-to-Capsule Distance (SCD) - SCD <25 mm → M probe - SCD ≥25 mm → XL probe
Practical algorithm (without pre-examination ultrasound): - BMI <32 kg/m² → Start with M probe - BMI ≥32 kg/m² → Start with XL probe - Use Automated Probe Selection (APS) tool on compatible devices
Quality-based switching: - If using M probe and >2 of 10 shots fail, switch to XL probe - If APS recommends XL probe, follow the recommendation
The critical finding from de Lédinghen et al. (2019) was that when appropriate probes are selected based on SCD, there is no significant difference in results: M probe results in patients with SCD <25 mm (median 8.8 kPa) did not significantly differ from XL probe results in matched patients with SCD ≥25 mm (median 9.1 kPa, p=0.175).
3.5 Consequences of Probe Mismatch
| Error | Consequence | Clinical Impact |
|---|---|---|
| M probe in obese patients (SCD ≥25 mm) | Overestimation of liver stiffness | False-positive cirrhosis diagnoses |
| XL probe in thin patients (SCD <25 mm) | Underestimation of liver stiffness | Missed significant fibrosis |
When strict selection criteria cannot be followed, Durango et al. (2013) proposed adjusted XL probe cut-offs: <5.5 kPa (F0), 5.5–7 kPa (F1–2), 7–10 kPa (F3), >10 kPa (F4).
4. Controlled Attenuation Parameter (CAP) for Steatosis
4.1 What CAP Measures
The Controlled Attenuation Parameter (CAP) is a VCTE-derived metric that quantifies ultrasound attenuation, which increases in proportion to hepatic fat content. CAP is measured simultaneously with liver stiffness during FibroScan examination, providing an estimate of steatosis severity without additional time or cost (Sasso et al., 2012).
CAP values are reported in decibels per meter (dB/m), with higher values indicating greater hepatic fat content. The measurement range is 100–400 dB/m.
4.2 Diagnostic Performance
Individual Patient Data Meta-Analysis (Karlas et al., 2017)
This landmark meta-analysis involving 2,735 patients established CAP diagnostic accuracy using liver biopsy as the reference standard:
| Steatosis Grade | Hepatocytes Affected | CAP Cut-off (dB/m) | AUROC |
|---|---|---|---|
| S ≥ 1 (mild) | ≥10% | 248 | 0.823 |
| S ≥ 2 (moderate) | ≥33% | 268 | 0.754 |
| S ≥ 3 (severe) | ≥66% | 280 | 0.703 |
Xu et al. Meta-Analysis (2022)
A more comprehensive meta-analysis including 61 studies and 10,537 patients with NAFLD confirmed these findings: - S ≥ S1: AUROC 0.924 - S ≥ S2: AUROC 0.794 - S = S3: AUROC 0.778
Eddowes et al. Prospective Study (2019)
This multicenter UK study across seven centers with 450 NAFLD patients provided refined Youden-optimized cut-offs: - S ≥ 1: 302 dB/m (AUROC 0.87) - S ≥ 2: 331 dB/m (AUROC 0.77) - S ≥ 3: 337 dB/m (AUROC 0.70)
4.3 Factors Affecting CAP Accuracy
Obesity: Patients with BMI ≥30 kg/m² demonstrate lower diagnostic accuracy. The Xu et al. (2022) meta-analysis found that mean CAP cut-offs in obese patients were 27–31 dB/m higher than in non-obese patients for equivalent steatosis grades.
Skin-to-Liver Capsule Distance: Increased subcutaneous fat reduces ultrasound penetration and affects CAP reliability.
Probe Selection: M and XL probes may yield different CAP values; proper probe selection based on body habitus is essential.
Diabetes: Some studies suggest CAP values require adjustment in diabetic patients.
4.4 Clinical Interpretation
The EASL 2021 guidelines note that while CAP values >250 dB/m generally indicate significant steatosis (>33%), cut-offs vary considerably across studies and populations. CAP should be interpreted alongside clinical context rather than as a standalone diagnostic (European Association for the Study of the Liver, 2021).
Practical interpretation: - CAP <248 dB/m: Minimal or no steatosis likely - CAP 248–280 dB/m: Mild to moderate steatosis - CAP >280 dB/m: Significant steatosis likely
5. Diagnostic Performance for Liver Fibrosis
VCTE has been the most extensively validated elastography technique for fibrosis assessment. Multiple meta-analyses have established its diagnostic accuracy across etiologies.
5.1 NAFLD/MASLD
Xu et al. Meta-Analysis (2022)
AUROC values for LSM by VCTE in NAFLD: - F ≥ 1: 0.851 - F ≥ 2 (significant fibrosis): 0.830 - F ≥ 3 (advanced fibrosis): 0.897 - F = 4 (cirrhosis): 0.925
Eddowes et al. Prospective Study (2019)
Optimized cut-offs for NAFLD derived from 450 patients with same-day biopsy: - F ≥ 2: 8.2 kPa (AUROC 0.77) - F ≥ 3: 9.7 kPa (AUROC 0.80) - F = 4: 13.6 kPa (AUROC 0.89)
5.2 Chronic Hepatitis B
The Guo et al. (2017) meta-analysis comparing MRE and VCTE demonstrated VCTE AUROC values in CHB patients: - Significant fibrosis (F ≥ 2): 0.796 - Advanced fibrosis (F ≥ 3): 0.893 - Cirrhosis (F4): 0.905
5.3 Chronic Hepatitis C
Foundational studies established VCTE performance in HCV (Castéra et al., 2005; Brazilian Society of Hepatology, 2021): - Significant fibrosis (F ≥ 2): AUROC 0.83–0.89 - Cirrhosis (F4): AUROC 0.94–0.96
Commonly used cut-offs for HCV: - F ≥ 2: 7.1 kPa - F ≥ 3: 9.5 kPa - F4: 12.5 kPa
5.4 Alcohol-Related Liver Disease
VCTE demonstrates excellent performance in ALD. The EASL 2021 guidelines recommend: - LSM <8 kPa: Rules out advanced fibrosis - LSM ≥12–15 kPa: Rules in advanced fibrosis/cirrhosis
Note that alcohol’s independent effect on liver stiffness may necessitate higher cut-offs compared to other etiologies (European Association for the Study of the Liver, 2021).
5.5 Summary of Etiology-Specific Cut-offs
| Etiology | F ≥ 2 | F ≥ 3 | F4 (Cirrhosis) |
|---|---|---|---|
| NAFLD/MASLD | 8.2 kPa | 9.7 kPa | 13.6 kPa |
| Chronic HCV | 7.1 kPa | 9.5 kPa | 12.5 kPa |
| Chronic HBV | 7.0 kPa | 8.0 kPa | 11.0 kPa |
| ALD | — | 8.0 kPa | 12–15 kPa |
Cut-offs vary by study; values shown are commonly cited thresholds. Clinical context should guide interpretation.
6. Quality Criteria and Examination Reliability
A reliable FibroScan examination requires adherence to specific quality criteria. Results that do not meet these standards may be unreliable and should be interpreted with caution.
6.1 Standard Quality Criteria
Per international guidelines and the Baveno VII consensus (de Franchis et al., 2022):
| Parameter | Requirement |
|---|---|
| Valid measurements | ≥10 |
| Success rate | ≥60% |
| IQR/Median ratio | <30% (when median LSM >7.1 kPa) |
| Fasting status | ≥2–3 hours |
| Appropriate probe | Based on SCD or BMI algorithm |
6.2 The IQR/Median Ratio
The interquartile range divided by the median (IQR/M) reflects measurement variability:
- IQR/M <30%: Reliable when median LSM >7.1 kPa
- IQR/M ≥30%: Indicates excessive variability; results may be unreliable
The IQR/M criterion applies primarily when LSM exceeds 7.1 kPa. At lower stiffness values, even small absolute variations can produce high IQR/M ratios without indicating poor quality.
6.3 Examination Technique
Patient positioning: - Supine position - Right arm maximally abducted - Intercostal approach at the mid-axillary line
Probe placement: - Right lobe of the liver - Perpendicular to skin surface - Intercostal space (avoiding ribs)
Measurement acquisition: - 10 valid measurements required - Quiet breath-hold during each measurement (not deep inspiration) - Wait for device readiness between measurements
6.4 When Quality Criteria Are Not Met
If a reliable examination cannot be achieved:
- Verify technique: Correct positioning, fasting status, probe selection
- Switch probes: If M probe fails frequently, try XL probe
- Repeat examination: Under optimized conditions
- Consider alternatives: MRE if available, or other elastography modalities
Modern devices with XL probes and APS tools achieve technical success in >95% of patients when properly utilized (de Lédinghen et al., 2019).
6.5 Reproducibility
When quality criteria are met, VCTE demonstrates excellent reproducibility. The study by Fraquelli et al. (2007) established intraclass correlation coefficients (ICC) exceeding 0.90 for both inter-observer and intra-observer agreement.
7. Clinical Applications
7.1 Baseline Staging in MASLD/MASH
Non-invasive fibrosis staging is fundamental in MASLD management. The EASL 2021 guidelines recommend a two-tier testing strategy:
- First-line: FIB-4 score in primary care/diabetes clinics
- Second-line: LSM by TE (or patented serum markers) for those with FIB-4 ≥1.3
Cut-offs for cACLD staging in NAFLD/MASLD: - Rule out cACLD: LSM <8 kPa - Indeterminate: LSM 8–12 kPa (consider repeat testing or additional markers) - Rule in cACLD: LSM ≥12–15 kPa
For patients with confirmed compensated advanced chronic liver disease (cACLD), the Baveno VII “rule of 5” stratifies prognosis (de Franchis et al., 2022): - LSM 10–15 kPa: Low risk of decompensation - LSM 15–20 kPa: Intermediate risk - LSM 20–25 kPa: High risk; consider CSPH assessment - LSM ≥25 kPa: Very high risk; CSPH highly likely (specificity >90%)
7.2 Monitoring Fibrosis Regression or Progression
FibroScan enables serial monitoring without repeated biopsies. The Baveno VII consensus defines clinically significant LSM improvement as (de Franchis et al., 2022):
- ≥20% decrease in LSM and final LSM <20 kPa, OR
- Any decrease resulting in LSM <10 kPa
Such improvements are associated with substantially reduced risk of decompensation and liver-related mortality.
Important caveat: The EASL 2021 guidelines caution that LSM reduction may reflect decreased inflammation rather than true fibrosis regression. LSM should not be used alone to confirm fibrosis regression; interpretation requires: - Laboratory parameters (ALT, AST normalization; platelet improvement) - Clinical context (etiology removal, absence of decompensation) - Time course (sustained improvement over ≥12 months)
7.3 Screening High-Risk Populations
Given the high prevalence of MASLD in metabolic syndrome populations, FibroScan-based screening is increasingly advocated:
- Type 2 Diabetes: MASLD prevalence exceeds 60%; advanced fibrosis present in 15–20%
- Obesity: Screening indicated when other metabolic risk factors present
- Metabolic Syndrome: High-risk population warranting proactive assessment
The EASL 2021 guidelines recommend FIB-4 as a cost-effective first-tier screen, with LSM for those with elevated FIB-4 (European Association for the Study of the Liver, 2021).
7.4 Portal Hypertension Assessment
The Baveno VII consensus established LSM-based criteria for non-invasive CSPH assessment:
Ruling out CSPH: - LSM ≤15 kPa plus platelet count ≥150 × 10⁹/L → CSPH ruled out (sensitivity >90%, NPV >90%)
Ruling in CSPH: - LSM ≥25 kPa → CSPH ruled in (specificity >90%, PPV >90%) in viral, alcohol-related, and non-obese NASH cACLD
Avoiding screening endoscopy: - Patients meeting Baveno VI criteria (LSM <20 kPa and platelets >150 × 10⁹/L) can safely avoid screening endoscopy - Patients not meeting these criteria should undergo endoscopy
Spleen stiffness measurement (SSM) on FibroScan 630 Expert: - SSM <21 kPa can rule out CSPH in viral hepatitis - SSM >50 kPa can rule in CSPH - SSM ≤40 kPa can identify patients at low probability of high-risk varices when Baveno VI criteria not met
7.5 Viral Hepatitis Management
Chronic Hepatitis B and C: - Pre-treatment staging to assess urgency and guide management - Post-SVR monitoring in HCV to assess regression - Note: Post-SVR cut-offs may differ from treatment-naive patients
Post-SVR surveillance (Baveno VII): Patients with HCV-induced cACLD who achieve SVR and show consistent post-treatment improvements with LSM values <12 kPa and PLT >150×10⁹/L can be discharged from portal hypertension surveillance, as they are at negligible risk of hepatic decompensation (de Franchis et al., 2022).
7.6 Recommended Monitoring Frequency
Annual or biannual FibroScan monitoring is recommended in several scenarios:
- MASLD/MASH: Annual LSM in patients with significant fibrosis risk factors
- Viral Hepatitis: Monitoring during and after treatment
- Alcohol-Related Liver Disease: Annual monitoring if continued exposure or during recovery
- Established cACLD: LSM “could be repeated every 12 months to monitor changes” (de Franchis et al., 2022)
For patients with normal or minimal fibrosis on stable disease, less frequent monitoring (every 2–3 years) may suffice.
8. Advantages of FibroScan
8.1 Standardization and Validation
FibroScan serves as the reference device in most major international guidelines, including those from EASL, AASLD, and the Baveno consensus conferences. The majority of published cut-off values for liver stiffness were derived using FibroScan, providing the most extensive validation of any elastography device.
8.2 Reproducibility
Inter-observer and intra-observer agreement is excellent, with intraclass correlation coefficients (ICC) typically exceeding 0.90 (Fraquelli et al., 2007). The standardized measurement protocol—same probe positioning, same acquisition technique, same quality criteria—minimizes operator-dependent variability.
8.3 Integrated Steatosis Assessment
The simultaneous measurement of CAP provides comprehensive liver assessment in a single examination, evaluating both fibrosis and steatosis without additional cost or time. This integrated approach is particularly valuable in MASLD, where both parameters inform prognosis and management.
8.4 Efficiency
A complete FibroScan examination takes 2–5 minutes, requires no patient preparation beyond fasting, and can be performed by trained non-physician operators. Results are available immediately, enabling same-visit clinical decision-making.
8.5 Point-of-Care Deployment
The portability of newer models (especially the 430 Mini+) enables screening in community settings, primary care offices, and mobile health units. This is critical for identifying at-risk populations before they develop advanced disease—bringing liver assessment to the patient rather than requiring specialist referral.
8.6 Patient Experience
FibroScan is non-invasive and painless. Patients may feel light pressure from the probe and a mild “thump” sensation from the mechanical vibrator, but no discomfort requiring analgesia. The examination requires no sedation, contrast agents, or injections, and patients can resume normal activities immediately.
9. Limitations and When to Consider Alternatives
9.1 No Anatomical Imaging
FibroScan provides no B-mode imaging. Focal liver lesions cannot be visualized, and the examination cannot serve as a general hepatic ultrasound. Patients may still require conventional imaging for complete liver assessment. This is a key advantage of ultrasound-integrated elastography alternatives (pSWE, 2D-SWE).
9.2 Obesity Challenges
Despite the XL probe, technical failure rates increase in morbidly obese patients (BMI >40 kg/m²). The de Lédinghen et al. (2019) study demonstrated that 77.7% of patients with BMI ≥32 kg/m² have SCD ≥25 mm, requiring XL probe use. For patients in whom reliable measurements cannot be obtained even with XL probe, MRE should be considered as MRE accuracy is unaffected by obesity.
9.3 Ascites Incompatibility
The presence of ascites prevents shear wave propagation to the liver, rendering VCTE technically impossible in patients with significant ascites. This is a fundamental physical limitation of the technology.
9.4 Confounders
Multiple non-fibrotic factors can falsely elevate LSM values:
| Factor | Mechanism | Clinical Action |
|---|---|---|
| Acute hepatitis (ALT >5× ULN) | Inflammation and edema | Defer until ALT normalizes |
| Extrahepatic cholestasis | Biliary obstruction | Exclude before interpreting |
| Hepatic congestion | Right heart failure | Optimize cardiac status |
| Recent meal (<2–3 hours) | Post-prandial portal hyperemia | Ensure fasting |
| Severe steatosis | Mild independent effect | Consider in context |
9.5 Cost Considerations
FibroScan devices represent a significant capital investment ($50,000–100,000+ depending on model and configuration). CAP measurement is proprietary to the Echosens platform. Healthcare systems with existing ultrasound machines may find ultrasound-integrated elastography more cost-effective.
9.6 Cannot Replace Biopsy for All Indications
FibroScan CAN replace biopsy for: - Ruling out advanced fibrosis in at-risk populations - Confirming cirrhosis when clinical context supports it - Serial monitoring of known liver disease - Risk stratification for portal hypertension
FibroScan CANNOT replace biopsy for: - Determining specific disease etiology (e.g., autoimmune vs. drug-induced) - Assessing inflammatory activity (grade) - Diagnosing NASH (requires histological assessment of ballooning) - Evaluating disease-specific features (interface hepatitis, bile duct damage) - Diagnosing rare liver diseases - Evaluating allograft rejection post-transplant
10. Frequently Asked Questions
Q1. Is FibroScan reliable?
FibroScan reliability depends on proper technique. When quality criteria are met (≥10 valid measurements, success rate ≥60%, IQR/M <30% when LSM >7.1 kPa), VCTE demonstrates excellent reproducibility with ICC values exceeding 0.90. Modern devices with XL probes and APS tools achieve technical success in >95% of patients when properly utilized (de Lédinghen et al., 2019; Fraquelli et al., 2007).
Q2. Why do obese patients need the XL probe?
The XL probe was developed to address measurement failures in patients with increased subcutaneous adipose tissue:
- Deeper penetration: 35–75 mm vs. 25–65 mm for M probe
- Lower frequency: 2.5 MHz vs. 3.5 MHz for better tissue penetration
- Reduced failure rate: From 16% (M probe) to 1% in overweight/obese patients (Myers et al., 2012)
The key criterion is skin-to-capsule distance (SCD), not BMI alone. Approximately 77% of patients with BMI ≥32 kg/m² have SCD ≥25 mm, requiring XL probe (de Lédinghen et al., 2019).
Q3. Is FibroScan painful?
No. Patients may feel light pressure from the probe and a mild “thump” sensation from the mechanical vibrator. The examination takes 5–10 minutes, requires no sedation or injections, and patients can resume normal activities immediately.
Q4. How often should I get a FibroScan?
Frequency depends on clinical context: - MASLD with risk factors: Annual - Established cACLD: Every 12 months (Baveno VII) - During treatment (viral hepatitis, lifestyle intervention): As clinically indicated - Minimal fibrosis, stable disease: Every 2–3 years
Q5. Can elevated FibroScan values be caused by something other than fibrosis?
Yes. Non-fibrotic factors that elevate LSM include: - Acute hepatitis (ALT >5× ULN) - Cardiac failure causing hepatic congestion - Extrahepatic cholestasis - Recent meals (<2–3 hours) - Severe steatosis (mild effect)
If elevated LSM is unexpected, consider repeating after addressing modifiable factors.
Q6. Does a decreasing FibroScan value mean my fibrosis is improving?
Possibly, but interpretation requires caution. Baveno VII defines clinically significant improvement as ≥20% decrease plus final LSM <20 kPa, or any decrease to <10 kPa. However, LSM reduction may reflect decreased inflammation rather than true fibrosis regression. Sustained improvement over ≥12 months with normalized liver enzymes provides stronger evidence of true regression (de Franchis et al., 2022; European Association for the Study of the Liver, 2021).
Summary
FibroScan® (VCTE) remains the most validated and widely used device for non-invasive liver assessment, offering standardized liver stiffness measurement and integrated steatosis assessment via CAP.
Key points:
Technology: VCTE uses mechanical vibration at 50 Hz to generate shear waves, tracked by ultrasound to measure stiffness in kPa
Device models: 430 Mini+ (portable), 530 Compact (clinic), and 630 Expert (advanced, with spleen stiffness capability)
Probe selection is critical: M+ for SCD <25 mm or BMI <32; XL+ for SCD ≥25 mm or BMI ≥32; wrong probe selection causes diagnostic errors
CAP provides simultaneous steatosis assessment; values >248–280 dB/m suggest significant fat
Diagnostic performance is excellent: AUROC >0.85 for advanced fibrosis and >0.90 for cirrhosis across etiologies
Quality criteria must be met: ≥10 valid measurements, success rate ≥60%, IQR/M <30%
Clinical applications include MASLD staging, monitoring treatment response, screening high-risk populations, and portal hypertension assessment per Baveno VII criteria
Limitations include no anatomical imaging, challenges in morbid obesity and ascites, and susceptibility to confounders (inflammation, congestion, non-fasting)
Biopsy still required for etiology diagnosis, inflammatory grading, and NASH diagnosis
FibroScan’s extensive validation, guideline integration, and practical efficiency make it the cornerstone of non-invasive liver assessment. Understanding proper technique, probe selection, and result interpretation enables clinicians to maximize its clinical utility.
Series navigation: - Article 1: Fundamentals of Liver Elastography — Concepts, Physics, and Clinical Framework - Article 2: FibroScan® (VCTE) — This article - Article 3: Alternatives to FibroScan® — Ultrasound-Based Elastography (pSWE & 2D-SWE)
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