Background and aimsSimilarly to the controlled attenuation parameter (CAP), the ultrasound-based attenuation imaging (ATI) can quantify hepatic steatosis. We prospectively compared the performance of ATI and CAP for the diagnosis of hepatic steatosis in patients with type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD) using histology and magnetic resonance imaging proton density fat fraction (MRI-PDFF) as references. MethodsPatients underwent ATI and CAP measurement, MRI, and biopsy on the same day. Steatosis was classified as S0, S1, S2, and S3 on histology (<5%, 5-33%, 33-66%, and >66%, respectively) while the thresholds of 6.4%, 17.4%, and 22.1%, respectively, were used for MRI-PDFF. The area under the curve (AUC) of ATI and CAP was compared using a DeLong test. ResultsSteatosis could be evaluated in 191 and 187 patients with liver biopsy and MRI-PDFF, respectively.For MRI–PDFF steatosis the AUC of ATI and CAP were 0.86 (95%C.I. 0.81–0.91) vs 0.69 (95%C.I. 0.62-0.75) for S0 vs S1-S3 (p=0.02) and 0.71 (95%C.I. 0.64–0.77) vs 0.69 (95%C.I. 0.61-0.75) for S0-S1 vs S2-S3 (p=0.60), respectively.For histological steatosis the AUC of ATI and CAP were 0.92 (95%C.I. 0.87-0.95) vs. 0.95 (95%C.I. 0.91-0.98) for S0 vs S1-S3 (p=0.64) and 0.79 (95%C.I. 0.72-0.84) vs. 0.76 (95%C.I. 0.69–0.82) for S0-S1 vs S2-S3 (p=0.61), respectively. ConclusionATI may be used as an alternative to CAP for the diagnosis and quantification of steatosis, in patients with T2D and NAFLD.