Comparison of liver stiffness measurements by a 2D-shear wave technique and transient elastography: results from a European prospective multi-centre study

Objectives To compare liver stiffness measurement (LSM) provided by Canon 2D-shear wave elastography (2D-SWE) and transient elastography (TE), the latter being the reference method. Methods Prospective study conducted in four European centres from 2015 to 2016 including patients with various chronic liver diseases who had LSMs with both 2D-SWE and TE on the same day. Median of 10 valid measurements (in kPa) was used for comparison using pairedttest, Pearson correlation, intraclass correlation coefficient (ICC) and Bland-Altman plot. The ability of 2D-SWE to stratify patient according to recognised LSM-TE thresholds was assessed by ROC curve analysis. Results Six hundred forty patients were scanned, where 593 (92.7%), 572 (89.4%) and 537 (83.9%) had reliable LSMs by TE, 2D-SWE and both combined, respectively. In the latter (n= 537, 310 [57.7%] male, mean 55.3 +/- 14.8 years), median LSM-TE and LSM-2D-SWE had a mean of 10.1 +/- 9.4 kPa (range 2.4-75) and 9.1 +/- 6.1 kPa (range 3.6-55.7) (pairedttest:p< 0.001), respectively. These were significantly correlated (Pearsonr= 0.932,p< 0.001, ICC 0.850 (0.825-0.872), bias 0.99 +/- 4.33 kPa [95% limits of agreement - 9.48 to + 7.49] with proportional error towards higher LSM values). LSM-2D-SWE values significantly increased with TE categories (ANOVA:p< 0.001). AUROCs ranged from 0.935 +/- 0.010 (95% CI 0.910-0.954) to 0.973 +/- 0.009 (95% CI 0.955-0.985), resulting in correct classification of 390/537 (73%) patients. Three 2D-SWE measurements were sufficient for reliable LSMs. Conclusion LSM using 2D-SWE correlates well with TE. It tends to underestimate higher stages of liver fibrosis but correctly classifies the majority of patients. It may be used in TE-derived algorithms to manage patients.