Steatosis index: a novel multiparametric ultrasound approach for accurate liver steatosis quantification and grading

Accurate quantification of liver steatosis is critical for diagnosing steatotic liver disease. We aimed to evaluate a newly developed Steatosis Index (SI), which integrates multiple quantitative ultrasound (US) parameters, for assessing liver steatosis in patients with chronic liver disease (CLD).

We retrospectively enrolled 568 patients with CLD who underwent both US attenuation coefficient (iATT) and MRI-proton density fat fraction (PDFF). With MRI-PDFF as a reference standard, we examined whether SI, developed by integrating backscatter coefficient and signal texture parameters into iATT, improves the accuracy of liver steatosis quantification and grading.

SI demonstrated a stronger correlation (Pearson's r = 0.85 vs. 0.78, p < 0.001) and better concordance (Lin's concordance correlation coefficient = 0.84 vs. 0.75, p < 0.001), as well as higher area under the receiver operating characteristic curve for differentiating each steatosis grade: 0.94 vs. 0.92 for grade ≥ 1, 0.95 vs. 0.90 for grade ≥ 2, and 0.93 vs. 0.88 for grade 3, all p < 0.001), compared to iATT. It also showed significant improvement in reclassification and discrimination metrics, with internal validation using bootstrap resampling confirming the reliability of these findings.

SI provided excellent diagnostic performance in quantifying and grading liver steatosis and may serve as a valuable tool for monitoring it in patients with CLD. Trial Registration UMIN Clinical Trials Registry, Number: UMIN000047411.