Comparison Between Attenuation Measurement and the Controlled Attenuation Parameter for the Assessment of Hepatic Steatosis Based on MRI Images

Background and aims: This study prospectively compared the diagnostic accuracies of the improved Attenuation Measurement (iATT) algorithm and the Controlled Attenuation Parameter (CAP) and assessed the interchangeability of iATT with magnetic resonance imaging-derived proton density fat fraction (MRI-derived PDFF).

Methods: Patients with chronic liver disease were prospectively enrolled and underwent iATT, CAP and MRI-derived PDFF measurements for hepatic steatosis evaluation. According to MRI-derived PDFF values, steatosis grades were categorised as steatosis (S)0 (< 5.2%), S1 (≥ 5.2%, < 11.3%), S2 (≥ 11.3%, < 17.1%) and S3 (≥ 17.1%). Correlation coefficients (CCs) were determined, diagnostic performances were compared by the area under the receiver operating characteristic curve (AUROC) and agreement was evaluated using the calculated percentage error (PE) and expected limit of agreement (LOA).

Results: A total of 414 patients (median age 64 years, 203 females) were evaluated. The CC between iATT and MRI-derived PDFF was 0.727 (95% confidence interval [CI] 0.678-0.770), which was higher than that between CAP and MRI-derived PDFF at 0.615 (95% CI 0.551-0.672) (p < 0.001). The AUROCs of iATT for ≥ S1, ≥ S2 and ≥ S3 were 0.901 (95% CI 0.870-0.931), 0.878 (95% CI 0.846-0.910) and 0.839 (95% CI 0.794-0.883), respectively. The diagnostic performances of iATT for ≥ S1 and ≥ S2 showed significantly higher AUROCs than those of CAP (p < 0.001, p = 0.036, respectively). The calculated PE and the expected LOA for CAP and iATT were 38.94% and 22.66% and 32.94% and 30.03%, respectively.

Conclusions: iATT was superior to CAP and comparable to MRI-derived PDFF in assessing hepatic steatosis.

Trial registration: This study was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN000047411).