Value of viscosity, viscoelasticity and attenuation measurement using shear wave ultrasound elastography

Nonalcoholic Liver Disease (NAFLD) is increasing in frequency in daily practice. Evaluation of such patients needs to assess steatosis, fibrosis and inflammation.A new Ultrasound(US) system from Canon noninvasively evaluates these parameters by measuring shear waves speed (2D-SWE) - related to viscoelasticity and fibrosis; dispersion (DI) - related to viscosity and inflammation, and attenuation parameter (ATI) - related to steatosis. Aim: To evaluate the usefulness of 2D-SWE, DI and ATI measurements obtained using Aplio i800 from Canon, for the noninvasive assessment of liver fibrosis, inflammation, and steatosis using Transient Elastography (TE) with Controlled Attenuation Parameter (CAP) as the reference method. Material and Method: 113 consecutive subjects were included in the study group, mostly NAFLD patients, in whom liver stiffness (LS) and steatosis were evaluated in the same session by means of 2 elastography techniques: TE with CAP (FibroScan, EchoSens) and 2D-SWE with ATI(Aplio I800, Canon). Reliable LS measurements were defined for TE as the median value of 10 measurements with an interquartile range/median ratio (IQR/M) To discriminate between TE fibrosis stages we used the following cut-offs [1]: F ≥ 2: 8.4 kPa and F4: 13.2 kPa and to discriminate between steatosis stages we used the following cut-offs recommended by the manufacturer: S1(mild) – 230db/m, S2(moderate) - 275db/m, S3(severe) - 300db/m. Results: Reliable LS measurements were obtained in 99.1% subjects by both 2D-SWE and TE.A very strong positive correlation was found between the LS values obtained by the 2 Methods: r = 0.88, p The best cut-off value for fibrosis, for F0/1 was ≤ 6.2 kPa (AUROC 0.82; Se = 75%; Sp = 85.5%), for F ≥ 2 it was 7.9 kPa (AUROC 0.96; Se = 90.4%; Sp = 95.6%), for F4 it was 11.7 kPa (AUROC 0.99; Se = 100%; Sp = 96%). Regarding steatosis, the best cut-off values were: for S1 = 0.64 dB/cm/mHz (AUROC 0.89; Se = 73.6%; Sp = 88.8%), for S2 = 0.79 dB/cm/mHz (AUROC 0.88; Se = 63.4%; Sp = 96.4%), for S3 = 0.86dB/cm/mHz (AUROC 0.95; Se = 45%; Sp = 100%). When we divided the cohort into healthy vs patients with chronic hepatopathies, we found out that the mean DI values in the pathology group were higher than in the healthy group(12.4 ± 2.7 vs 11.5 ± 1.9, p = 0.03) Conclusion: 2D-SWE and ATI measurements with the new system strongly correlate with TE and CAP results 110.1111/apt.14529