Two-dimensional shear wave elastography and ultrasound-guided attenuation parameter for progressive non-alcoholic steatohepatitis

Abstract

Background and aims: We investigated the usefulness of combining two-dimensional shear wave elastography and the ultrasound-guided attenuation parameter for assessing the risk of progressive non-alcoholic steatohepatitis, defined as non-alcoholic steatohepatitis with a non-alcoholic fatty liver disease activity score of ≥4 and a fibrosis stage of ≥2.

Methods: This prospective study included 202 patients with non-alcoholic fatty liver disease who underwent two-dimensional shear wave elastography, ultrasound-guided attenuation parameter, vibration-controlled transient elastography, the controlled attenuation parameter, and liver biopsy on the same day. Patients were grouped according to liver stiffness measurement using two-dimensional shear wave elastography and the attenuation coefficient, assessed using the ultrasound-guided attenuation parameter: A, low liver stiffness measurement/low attenuation coefficient; B, low liver stiffness measurement/high attenuation coefficient; C, high liver stiffness measurement/low attenuation coefficient; and D, high liver stiffness measurement/high attenuation coefficient.

Results: Two-dimensional shear wave elastography and vibration-controlled transient elastography had equivalent diagnostic performance for fibrosis. The areas under the curve of the ultrasound-guided attenuation parameter for identifying steatosis grades ≥S1, ≥S2, and S3 were 0.89, 0.91, and 0.92, respectively, which were significantly better than those of the controlled attenuation parameter (P<0.05). The percentages of progressive non-alcoholic steatohepatitis in Groups A, B, C, and D were 0.0%, 7.7%, 35.7%, and 50.0%, respectively (P<0.001). The prediction model was established as logit (p) = 0.5414 × liver stiffness measurement (kPa) + 7.791 × attenuation coefficient (dB/cm/MHz)-8.401, with area under the receiver operating characteristic curve, sensitivity, and specificity values of 0.832, 80.9%, and 74.6%, respectively; there was no significant difference from the FibroScan-aspartate aminotransferase score.

Conclusion: Combined assessment by two-dimensional shear wave elastography and the ultrasound-guided attenuation parameter is useful for risk stratification of progressive non-alcoholic steatohepatitis and may be convenient for evaluating the necessity of specialist referral and liver biopsy.

Fig 1. Flow diagram of the study population.

2D SWE, 2D shear wave elastography; UGAP, ultrasound-guided attenuation parameter; VCTE, vibration-controlled transient elastography; CAP, controlled attenuation parameter; LB, liver biopsy.

Fig 2. Patient distribution according to histopathologic evaluation, LSM, and AC.

Fibrosis stage (a), steatosis grade (b), inflammation grade (c), and ballooning grade (d). LSM, liver stiffness measurement; AC, attenuation coefficient.

Fig 3. NASH or progressive NASH patient distribution according to LSM and AC.

a, c: All patients with nonalcoholic fatty liver disease were divided into four groups, according to the cutoff values of LSM and AC for fibrosis stage ≥ F1 and steatosis grade ≥ S1 [NASH (a), progressive NASH (c)]. b, d: Percentage of NASH (b) or progressive NASH (d) patients in each group. Percentages of NASH patients in Groups A, B, C, and D were 0.0% (0/14), 36.5% (19/52), 67.97% (19/28), and 78.7% (85/108), respectively; there was a significant difference in the distribution among groups (P < 0.001) (b). Percentages of progressive NASH patients in Groups A, B, C, and D were 0.0% (0/14), 7.7% (4/52), 35.7% (10/28), and 50.0% (54/108), respectively; there was a significant difference in the distribution among groups (P < 0.001) (d). LSM, liver stiffness measurement; AC, attenuation coefficient.