Résumé
Objective: nonalcoholic fatty liver disease, or hepatic steatosis, affects a quarter of the world’s population, making it a major public health challenge. The development of accessible non-invasive methods is of crucial importance for the detection and monitoring of this disease. This study assessed the performance of ultrasound using a dual intercostal and subcostal approach for the diagnosis of the steatosis via three ultrasound markers: attenuation coefficient, backscattering coefficient and speckle statistics modeled by a Nakagami distribution. The PDFF score measured with MRI was used as a benchmark.Materials and methods: one hundred thirty-three patients were included in this retrospective, bicentric study. MRI and abdominal ultrasound exams were performed successively. For both intercostal and subcostal approaches, the three ultrasound markers were compared with the PDFF score.Results: all three ultrasound markers were well correlated with the PDFF score: intercostal attenuation coefficient r²=0.72 and subcostal attenuation coefficient r²=0.65, intercostal backscattering coefficient r²=0.68 and subcostal backscattering coefficient r²=0.69, intercostal Nakagami m-parameter r²=0.51 and subcostal Nakagami m parameter r²=0.52. Combining these three ultrasound markers obtained from the inter-and subcostal acquisitions yielded an ultrasound fat fraction (UFF) that was strongly correlated with the PDFF score (r²=0.79).Conclusion: the intercostal and subcostal approaches can be used to quantify hepatic steatosis; when the two approaches are combined, this improves the correlation with the PDFF score.