Comparison of four different Shear Wave Elastography platforms according to abdominal wall thickness in liver fibrosis evaluation: a phantom study.

Aims: To compare the applicability, reliability and stiffness values of four different shear wave elastography (SWE) platforms and to determine the influence of abdominal wall thickness on those of four SWE platforms evaluating liver fibrosis. Material and methods: We used four different SWE platforms: transient elastography (TE), pSWE (S-shear wave), 2D SWE/ SSI (SuperSonic Imagine) and 2D SWE/GE (GE Health care). To identify the effect of abdominal wall thickness, five commercially available liver fibrosis phantoms were covered in 1.3 cm and 2.3 cm thick porcine abdominal walls, respectively. All measurements were performed by three observers. Absolute repeatability of each measurement was evaluated using coefficients of variation (CVs). Applicability rate, CVs and mean stiffness values were compared according to platforms and abdominal wall thickness.

Results: Applicability rates were significantly different among the four SWE platforms (p<0.001): 2DSWE/SSI showed the lowest applicability rate (68.9%) compared with the other three platforms (TE, 95.6%, pSWE, 93.3%, 2D SWE/GE, 97.8%) due to higher technical failure rates in phantoms with thick wall. Repeatability was significantly different according to the platform and abdominal wall thickness. Stiffness values did not significantly differ according to abdominal wall thickness, even though the values were significantly different among four platforms in all phantoms.

Conclusions: The applicability, repeatability, and stiffness value were different depending on SWE platforms. Further, the applicability and repeatability would be more affected by abdominal wall thickness. Thus, careful consideration should be given to an appropriate SWE platform, when evaluating liver fibrosis in patients with thick abdominal wall.