Diagnostic performance of attenuation imaging versus controlled attenuation parameter for hepatic steatosis with MRI-based proton density fat fraction as the reference standard: a prospective multicenter study.

Background: Attenuation Imaging (ATI) and controlled attenuation parameter (CAP) are non-invasive ultrasound-based methods for diagnosing hepatic steatosis. However, reports on the clinical usefulness of ATI are limited. We aimed to compare the ability of ATI and CAP to diagnose hepatic steatosis with magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) as the reference standard.

Methods: We performed a prospective multicenter study of 562 patients with chronic liver disease who underwent ATI, CAP, and MRI-PDFF. Patients with skin-to-liver capsule distance (SCD) ≤ 25 mm underwent CAP with an M probe; those with SCD > 25 mm underwent CAP with an XL probe. MRI-PDFF was used as the reference standard: S0 corresponds to MRI-PDFF < 5.2%, S1 to 5.2% ≤ MRI-PDFF < 11.3%, S2 to 11.3% ≤ MRI-PDFF < 17.1%, and S3 to MRI-PDFF ≥ 17.1%.

Results: The correlation coefficients for ATI and MRI-PDFF stratified by body mass index (< 30, ≥ 30 kg/m²), SCD (< 25, ≥ 25 mm), 2-dimensional share wave elastography (< 1.8 m/s), fibrosis-4 index (≤ 2.67), albumin-bilirubin score (< - 2.60) and type IV collagen 7 s (< 5.0 ng/ml) were significantly higher than those for CAP and MRI-PDFF. Areas under the receiver operating characteristics (95% CI) for ATI and CAP were 0.895 (0.869-0.922) and 0.845 (0.809-0.881) for ≥ S1 steatosis, 0.944 (0.926-0.963) and 0.881(0.852-0.910) for ≥ S2 steatosis, and 0.928 (95% CI 0.906-0.950) and 0.860 (95% CI 0.829-0.890) for S3 steatosis. ATI had higher diagnostic performance for all hepatic steatosis grades than CAP.

Conclusions: ATI is a more useful non-invasive method for diagnosing hepatic steatosis than CAP.