Abstract: Objective The purpose of this study was to investigate diagnostic performance of ultrasound-derived fat fraction (UDFF) in patients with metabolic associated fatty liver disease (MAFLD). Methods 54 allegedpatients with fatty liver were encountered in our hospital between October and December 2023, and all received MRI proton density fat fraction sequence (MRI-PDFF) and UDFF examination simultaneously. Intragroup correlation coefficient (ICC) was conducted to compare the consistency, and area underreceiver operating characteristic curve (AUC) was applied to assess the diagnostic efficacy. Results Based onMRI-PDFF results, non-fatty liver was found in 16 cases, mild fatty liver in 28 cases, moderate fatty liver in 3 cases and severe fatty liver in 7 cases; UDFF in 10 patients with moderate/severe fatty liver was 20.5(15.8, 28.0) %, much higher than [13.0(11.0,17.0)%, P＜0.01] in 28 patients with mild fatty liver or [5.5(4.0,7.0)%, P＜0.01] in 16 persons without fatty liver; ICC between MRI-PDFF and UDFF was 0.808,presenting as satisfactory diagnostic consistency; AUC in diagnosing MAFLD by UDFF was 0.987 (P<0.001), when the cut-off value was set as 8.0%,with the sensitivity (Se) of 97.4%, and the specificity (Sp) of 93.8%, and the AUC in diagnosing moderate/severe fatty liver was 0.908(P<0.001), when the cut-off value was set as 14.0%, with Se of 91.7% and Sp of 79.6%; our study didn't found difference of point shear wave elastography (pSWE) among individuals with or without fatty liver(P>0.05). Conclusion We recommendUDFF for diagnosis of metabolic associated fatty liver disease as its excellent efficacy, while the application of pSWE still needs multiple center validation.

Key words: Metabolic associated fatty liver disease, MRI proton density fat fraction sequence, Ultrasonic-derived fat fraction, Diagnosis