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Aim: Hitherto, breathing phases impact on hepatic steatosis measurements with quantitative ultrasound method in patients with liver fibrosis is not well known. The aim of the study was to evaluate different breathing phases for the ultrasound guided attenuation parameter (UGAP) technology for hepatic steatosis in patients with liver fibrosis.

Material and methods: Healthy controls and a cohort with steatosis and fibrosis was prospectively enrolled between September 2022 and October 2024. Presence of hepatic steatosis (≥ S1) with UGAP was defined as magnetic resonance imaging ≥ 5 % proton density fat fraction (PDFF), and presence of fibrosis was evaluated with magnetic resonance elastography. In a group with N = 55 measurements were sampled during normal breath hold, peak-inspiration and end-expiration phases. In a group with n = 37 free breathing phase was added during recorded volume sampling for measurements after examination. The diagnostic performance of UGAP for all four breathing methods were evaluated based on area under the receiver operating characteristic curve (AUROC) with PDFF.

Results: In group N = 55 no difference in diagnostic performance was seen between AUC for normal breath hold 0.79 (95 %CI: 0.66–0.92), inspiration 0.78 (95 %CI: 0.64–0.91) and expiration 0.77 (95 %CI: 0.64–0.91). In group n = 37 no difference was seen between AUC for normal breath hold 0.71 (95 %CI: 0.53–0.89), inspiration 0.66 (0.47–0.85), expiration 0.67 (95 %CI: 0.49–0.86) and free breathing 0.72 (95 %CI: 0.55–0.90). No difference between normal breath-hold UGAP mean values dB/cm/MHz and all tested breathing phases mean values (n = 37, NS).

Conclusion: Patients with liver fibrosis and inability to hold their breath during measurements for hepatic steatosis can be measured using UGAP technology with sustained diagnostic accuracy.