Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common chronic liver condition globally, often progressing silently until advanced fibrosis develops. Identifying liver fibrosis at earlier stages is crucial, yet the traditional diagnostic gold standard—liver biopsy—is invasive and unsuitable for routine monitoring. As non-invasive alternatives, two-dimensional shear wave elastography (2D-SWE) and vibration-controlled transient elastography (VCTE) have emerged as prominent imaging techniques. A recent study prospectively evaluated and compared the diagnostic performance of these two modalities in patients with biopsy-confirmed MASLD, focusing particularly on a cohort with higher obesity prevalence in Northeast China.
Non-Invasive Imaging for Fibrosis Assessment
Liver fibrosis is the most critical predictor of adverse outcomes in MASLD, prompting the need for accurate, accessible and non-invasive diagnostic tools. VCTE has gained widespread adoption for liver stiffness measurement (LSM) through devices such as FibroScan, but it lacks flexibility in region selection and is limited in patients with ascites. Conversely, 2D-SWE, implemented using the LOGIQ Fortis system, allows real-time mapping and region-specific measurements, with improved applicability in individuals with obesity and ascites.
The study enrolled 91 participants undergoing liver biopsy, with 75 ultimately included in the final analysis due to criteria such as measurement reliability and histological confirmation of steatosis. Both VCTE and 2D-SWE were performed on the same day as biopsy, providing a controlled basis for comparing their diagnostic accuracy. Participants had a high mean BMI (31.92 kg/m²), and the Penetration mode of the ultrasound system was used to enhance measurement success by improving signal penetration in patients with high subcutaneous fat.
Diagnostic Performance and Correlations
Both 2D-SWE and VCTE showed strong diagnostic capabilities in detecting fibrosis. For 2D-SWE, the area under the ROC curve (AUC) was 0.91 for detecting any fibrosis (F ≥ 1) and 0.94 for significant fibrosis (F ≥ 2). The optimal cutoff values were 6.1 kPa and 7.66 kPa, respectively. Sensitivities ranged from 84% to 90%, while specificities reached up to 95.1%. VCTE yielded slightly lower AUCs of 0.85 and 0.91 for the same fibrosis thresholds, with sensitivities up to 92.7% but lower specificity in mild fibrosis detection.
No statistically significant differences were found between the two modalities for either fibrosis threshold. However, the analysis showed nuanced differences in cutoff points when prioritising either sensitivity or specificity. For example, achieving over 90% sensitivity required slightly lower thresholds, while achieving specificity above 90% demanded higher cutoffs.
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Correlation analysis revealed that LSMs from both techniques were positively associated with fibrosis stage, lobular inflammation, ballooning, age and liver enzyme levels. For 2D-SWE, additional correlations were found with total and low-density lipoprotein cholesterol levels. A strong overall correlation (r = 0.77) was observed between 2D-SWE and VCTE measurements, although this correlation weakened in individuals with a BMI ≥ 32 kg/m², suggesting the influence of obesity on measurement consistency.
Factors Influencing Measurement Accuracy
Multivariable regression analyses provided further insights into variables influencing LSM reliability. For 2D-SWE, key predictors included fibrosis stage, skin-to-liver capsule distance (SCD), maximum liver lobe diameter, HDL cholesterol and triglyceride levels. For VCTE, fibrosis stage and SCD emerged as the primary factors.
SCD plays a critical role in both techniques, as greater distances can attenuate the ultrasound signal and reduce accuracy. Although VCTE’s XL probe is designed for obese patients, it does not entirely mitigate SCD-related limitations. The stronger correlation between 2D-SWE and VCTE in advanced fibrosis stages suggests that both methods are more consistent in diagnosing significant liver damage but may vary more in early disease detection or in patients with high BMI.
The influence of hepatic steatosis on LSMs remains debatable. This study found no significant correlation between steatosis grade and LSM, supporting the view that fibrosis is the primary driver of stiffness measurements. However, the limited number of patients with severe inflammation may have reduced the observed impact of inflammatory changes. These results align with previous research suggesting that metabolic and histological features, rather than steatosis alone, influence LSMs.
The study confirmed that both 2D-SWE and VCTE are effective non-invasive tools for assessing liver fibrosis in MASLD patients, with no significant difference in diagnostic performance. 2D-SWE offers added flexibility and higher specificity in some contexts, especially among obese populations. Key factors such as BMI, SCD and lipid metabolism markers can influence measurement accuracy and should be considered when interpreting LSM values. Future studies should expand to multi-centre settings and explore the role of histological and metabolic factors in refining diagnostic strategies for liver fibrosis.
Source: Academic Radiology
Image Credit: iStock
