Evaluation of Inter-System Variability in Liver Stiffness Measurements

Giovanna Ferraioli, Annalisa De Silvestri, Raffaella Lissandrin, Laura Maiocchi, Carmine Tinelli, Carlo Filice, Richard G Barr

Research output: Contribution to journalArticlepeer-review


AIM:  The primary aim of this study was to determine the inter-system variability of liver stiffness measurements (LSMs) in patients with varying degrees of liver stiffness. The secondary aim was to determine the inter-observer variability of measurements. MATERIALS AND METHODS:  21 individuals affected by chronic hepatitis C and 5 healthy individuals were prospectively enrolled. The assessment of LSMs was performed using six ultrasound (US) systems, four of which with point shear wave elastography (p-SWE) and two with 2 D shear wave elastography (2D-SWE) systems. The Fibroscan (Echosens, France) was used as the reference standard. Four observers performed the measurements in pairs (A-B, C-D). The agreement between different observers or methods was calculated using Lin's concordance correlation coefficient. The Bland-Altman limits of agreement (LOA) were calculated as well. RESULTS:  There was agreement above 0.80 for all pairs of systems. The mean difference between the values of the systems with 2D-SWE technique was 1.54 kPa, whereas the maximum mean difference between the values of three out of four systems with the pSWE technique was 0.79 kPa. The intra-patient concordance for all systems was 0.89 (95 % CI: 0.83 - 0.94). Inter-observer agreement was 0.96 (95 % CI: 0.94 - 0.98) for the pair of observers A-B and 0.93 (95 % CI: 0.89 - 0.96) for the pair of observers C-D. CONCLUSION:  The results of this study show that the agreement between LSMs performed with different US systems is good to excellent and the overall inter-observer agreement in "ideal conditions" is above 0.90 in expert hands.
Original languageEnglish
Pages (from-to)64-75
Number of pages12
JournalUltraschall in der Medizin
Issue number1
Publication statusPublished - Feb 2019


  • Case-Control Studies
  • *Elasticity Imaging Techniques
  • *Hepatitis C, Chronic/diagnostic imaging
  • Humans
  • Liver
  • Observer Variation
  • Reproducibility of Results


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