Usefulness of Controlled Attenuation Parameter in Detecting and Monitoring Hepatic Steatosis with MRI-PDFF as Reference

Background Controlled attenuation parameter (CAP) has been developed to estimate the extent of hepatic steatosis. Aims The purpose was to evaluate the usefulness of CAP in assessing hepatic steatosis and its change using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as reference standard. Methods Consecutive patients with liver steatosis were enrolled prospectively. We assessed hepatic steatosis with CAP and MRI-PDFF at enrollment and 12-month follow-up. The correlations between the two methods were analyzed. With MRI-PDFF as reference, the performance of CAP in diagnosis of steatosis severity and its changes was assessed. Results A total of 50 patients were enrolled, and 45 of them had follow-up MRI-PDFF and CAP at a median interval of 399 days. The mean hepatic steatosis was 13.4% by MRI-PDFF and 291.6 dB/m by CAP. There were positive correlations between CAP and MRI-PDFF in steatosis severity and its change. The median value of CAP was 254, 301.5, and 329.5 dB/m for steatosis 20%, respectively. For CAP in detecting steatosis ≥ 10% and > 20%, the diagnostic performance was 0.821 and 0.814. With the cutoff of 275 dB/m for ≥ 10% steatosis, the positive predictive value was 84.8%. With the cutoff of 325 dB/m for > 20% steatosis, the negative predictive value was 91.9%. In multiple linear regression, one dB/m change by CAP was associated with 0.039% change by MRI-PDFF. Conclusions In assessing liver fat content, CAP correlated with MRI-PDFF and was useful for detection and monitoring of hepatic steatosis.