The Hepatic Steatosis Diagnostic Performance Using Attenuation Imaging With the Magnetic Resonance Imaging‐Based Proton Density Fat Fraction as the Reference Standard: A Large, Prospective, Multicenter Cohort Study in Japan

BACKGROUND: Attenuation imaging (ATI) is used for the noninvasive diagnosis of hepatic steatosis (HS) based on the ultrasound system. However, the clinical utility of ATI has not yet been sufficiently evaluated. In this study, we used the magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) as a reference standard to investigate the usefulness of ATI in diagnosing HS. METHODS: We conducted a prospective multicenter study that included 1059 patients with chronic liver disease who underwent ATI and MRI-PDFF. We defined the degree of steatosis as follows: S0, MRI-PDFF < 5.2%; S1, 5.2% ≤ MRI-PDFF < 11.3%; S2, 11.3% ≤ MRI-PDFF < 17.1%; and S3, MRI-PDFF ≥ 17.1%, based on previously published studies. RESULTS: Because the MRI-PDFF data were not normally distributed, log-transformed data (log MRI-PDFF) were used for the analyses. The correlation coefficient between ATI values and log MRI-PDFF was high (r = 0.779). A Bland-Altman analysis revealed that ATI values and log MRI-PDFF showed good consistency with a mean bias of 0.000 and a narrow range of agreement (95% confidence interval [CI], -0.519-0.519). The areas under the receiver operating characteristic curve (95% CI) and cutoff values for ATI were 0.910 (0.893-0.928) and 0.65 dB/cm/MHz for ≥ S1 steatosis, 0.928 (0.913-0.944) and 0.69 dB/cm/MHz for ≥ S2 steatosis, and 0.913 (0.894-0.931) and 0.72 dB/cm/MHz for ≥ S3 steatosis, respectively. CONCLUSIONS: ATI is an excellent and beneficial noninvasive technique for the evaluation of HS. TRIAL REGISTRATION: UMIN Clinical Trials Registry (UMIN000048672).