Relationship Between Grayscale Ultrasound and Attenuation Imaging in the Evaluation of Hepatic Steatosis

Non-alcoholic fatty liver disease is emerging as a global health concern. Screening is the only way to alleviate its burden. Grayscale evaluation is the most commonly used non-invasive method for this purpose, but it lacks precision and reproducibility. In contrast, attenuation imaging is an innovative technique that has not yet been extensively studied. The aim of our study is to determine the correlation between hepatic steatosis grading obtained through attenuation measurement and grayscale ultrasound assessment performed by both a physician and a resident. In addition, we aim to evaluate the reproducibility of results obtained using both methods. A prospective study was conducted on 112 patients who underwent 2 double-blinded ultrasound examinations executed by an experienced radiologist with 30 years of expertise and a fifth-year resident from October to December 2023. Consequently, for each patient, a grayscale assessment of liver fat and attenuation coefficient measurement was done by the 2 readers, and graded accordingly. For attenuation coefficient, 5 measurements were taken with respect to the quality criteria set by the vendor. No significant difference was shown in the grading of liver fat using subjective method and attenuation imaging, obtained by the physician and the resident. Our results showed good reproducibility for grading fat liver using grayscale (Cohen Kappa=0.682) and attenuation imaging (Cohen Kappa=0.729) and excellent agreement for attenuation coefficient (ICC=0.956, 2k model). Attenuation imaging is an objective ultrasound application, with better inter-observer evaluation compared with grayscale evaluation, which remains a subjective method.