The Role of Multiparametric US of the Liver or the Evaluation of Nonalcoholic Steatohepatitis

Background: Nonalcoholic steatohepatitis (NASH) is diagnosed with histopathologic testing, but noninvasive surrogate markers are desirable for screening patients who are at high risk of NASH. Purpose: To investigate the diagnostic performance of dispersion slope, attenuation coefficient, and shear-wave speed measurements obtained using two-dimensional (2D) shear-wave elastography (SWE) in assessing inflammation, steatosis, and fibrosis and in the noninvasive diagnosis of NASH in patients suspected of having nonalcoholic fatty liver disease (NAFLD). Materials and Methods: This prospective study collected data from 120 consecutive adults who underwent liver biopsy for suspected NAFLD and were enrolled between April 2017 and March 2019. Three US parameters (dispersion slope [(m/sec)/kHz], attenuation coefficient [dB/cm/MHz], and shear-wave speed [in meters per second]) were measured using a 2D SWE system immediately before biopsy. The biopsy specimens were scored by one expert pathologist according to the Nonalcoholic Steatohepatitis Clinical Research Network criteria (119 participants underwent a histologic examination). Diagnostic performance was assessed using the area under the receiver operating characteristic curve (AUC) for the categories of inflammation, steatosis, and fibrosis. Results: One hundred eleven adults (mean age, 53 years 6 18 [standard deviation]; 57 men) underwent a US examination. Dispersion slope enabled the identification of lobular inflammation, with an AUC of 0.95 (95% confidence interval [CI]: 0.91, 0.10) for an inflammation grade greater than or equal to A1 (mild), 0.81 (95% CI: 0.72, 0.89) for an inflammation grade greaterthan or equal to A2 (moderate), and 0.85 (95% CI: 0.74, 0.97) for an inflammation grade equal to A3 (marked). Attenuation coefficient enabled the identification of steatosis, with an AUC of 0.88 (95% CI: 0.80, 0.97) for steatosis grade greater than or equal to S1 (mild), 0.86 (95% CI: 0.79, 0.93) for steatosis grade greater than or equal to S2 (moderate), and 0.79 (95% CI: 0.68, 0.89) forsteatosis grade equal to S3 (severe). Shear-wave speed enabled the identification of fibrosis, with an AUC of 0.79 (95% CI: 0.69, 0.88) for fibrosis stage greater than or equal to F1 (portal fibrosis), 0.88 (95% CI: 0.82, 0.94) for fibrosis stage greater than or equal to F2 (periportal fibrosis), 0.90 (95% CI: 0.84, 0.96) for fibrosis stage greater than or equal to F3 (septal fibrosis), and 0.95 (95% CI: 0.91, 0.99) for fibrosis stage equal to F4 (cirrhosis). The combination of dispersion slope, attenuation coefficient, and shear wavespeed showed an AUC of 0.81 (95% CI: 0.71, 0.91) for the diagnosis of NASH. Conclusion: Dispersion slope, attenuation coefficient, and shear-wave speed were found to be useful for assessing lobular inflammation, steatosis, and fibrosis, respectively, in participants with biopsy-proven nonalcoholic fatty liver disease. (C) RSNA, 2020