2D-SWE and FibroScan Discrepancies in Liver Fibrosis Staging: Which Method to Trust
Why Methods Diverge
Transient elastography (TE, FibroScan) and 2D-SWE are different shear wave elastography technologies. According to EFSUMB (Dietrich et al., 2017), in chronic hepatitis C, 2D-SWE (SSI) demonstrated high diagnostic accuracy for identifying significant and advanced fibrosis and cirrhosis (AUC>0.90), with 2D-SWE showing higher diagnostic efficacy than TE and serum fibrosis markers (FIB-4, APRI, Forns index). In 102 patients with obesity and CHC, 2D-SWE provided excellent accuracy for detecting severe fibrosis and cirrhosis (AUROC>0.90 for both).
According to the EFSUMB Course Book (Sporea et al., 2018), 2D-SWE.SSI had significantly higher accuracy than TE for diagnosing advanced fibrosis (F>3), and higher than VTQ (ARFI) for significant fibrosis (F>2). However, for diagnosing moderate fibrosis and cirrhosis, no significant differences were observed among all methods.
Comparison of Sensitivity (with TE as Reference)
According to WFUMB (Ferraioli et al., 2018), using TE as the reference method:
| Stage | Sensitivity p-SWE | Sensitivity 2D-SWE |
|---|---|---|
| F1 | 71.4% | 92.8% |
| F2 | 77.8% | 83.3% |
| F3 | 62.5% | 87.5% |
| F4 | 71.4% | 85.7% |
Important: no general conclusions allowing for fibrosis staging have been made to date (Ferraioli et al., 2018). p-SWE and 2D-SWE may have advantages in differentiating various stages of fibrosis.
What to Check in Case of Discrepancy
Threshold values for fibrosis are device-specific and measured in m/s, similar to ARFI (Diagnostic Ultrasound: Abdomen & Pelvis, 2022). Limitations of 2D-SWE and potential sources of discrepancies include confounding effects of edema, inflammation, and hepatic congestion, as well as operator dependency.
When assessing the quality of the study, ensure that conditions are met (example protocol for ElastPQ/point SWE): fasting ≥4 hours, supine position with right arm overhead, intercostal access through the right lobe (segments V–VIII), depth of the region of interest 1–3 cm from the capsule. Acceptability criterion for measurements is IQR/Med ≤ 30% with 10 measurements. Reasons for unacceptable results include obesity, ascites, cholestasis, heart failure, inflammatory episode.
Approximate Thresholds (for Context)
According to EFSUMB for ElastPQ (point SWE): F0–F1 < 7.0 kPa; F≥2 ≥ 7.0 kPa; F≥3 ≥ 9.0–9.5 kPa; F4 (cirrhosis) ≥ 12.0–13.0 kPa. Exact thresholds vary by etiology — higher in ALD and cholestasis, lower in NAFLD. TE and 2D-SWE thresholds are not directly interchangeable, explaining part of the discrepancies.
Practical Conclusion
No absolute "winner" is declared by source fragments: no unified conclusions on staging exist. However, in the studies presented, 2D-SWE demonstrated higher or comparable accuracy relative to TE, especially for significant/advanced fibrosis and in patients with obesity. In case of conflicting results, assess the quality of each measurement, presence of inflammation (ALT), congestion, and clinical context. [clarification needed — no unified algorithm for method selection in case of discrepancies in fragments]
Frequently asked questions
Which method is more accurate for advanced fibrosis (F>3)?
According to the EFSUMB Course Book (Sporea et al., 2018), 2D-SWE.SSI had significantly higher accuracy than TE for diagnosing advanced fibrosis (F>3), p=0.0016.
Is there a difference between methods in cirrhosis?
According to Sporea et al. (2018), for diagnosing cirrhosis (as well as moderate fibrosis), no significant differences were observed between 2D-SWE.SSI, TE, and VTQ (ARFI).
Can TE and 2D-SWE thresholds be directly compared?
No. Threshold values are device-specific and measured in m/s (Diagnostic Ultrasound, 2022); thresholds depend on the method and etiology, causing discrepancies.
What distorts the 2D-SWE result?
Confounding effects of edema, inflammation, and hepatic congestion, as well as operator dependency (Diagnostic Ultrasound, 2022). Obesity, ascites, cholestasis, and heart failure also have an impact.
How to ensure the validity of the measurement?
Acceptability criterion is IQR/Med ≤ 30% with 10 measurements, fasting ≥4 hours, intercostal access through the right lobe, depth of ROI 1–3 cm from the capsule (example protocol for ElastPQ).