Non-invasive assessment of steatosis in living liver donors: Correlation of shear wave elastography and blood cholesterol with histology

Background: Non-invasive methods such as two-dimensional shear wave elastography (2D-SWE) and blood biochemical markers are increasingly used to screen potential living liver donors for hepatic steatosis. This study aimed to evaluate the correlation between pre-operative 2D-SWE measurements, blood cholesterol levels, and the presence of mild hepatic steatosis (HS) confirmed liver biopsy in a cohort of living-donor liver transplantation (LDLT) candidates.
Methods: We retrospectively analyzed 158 LDLT donors who underwent pre-operative assessments, including 2D-SWE (mean kPa), total blood cholesterol (mmol/L), and liver biopsy for quantification of HS percentage at a single transplant center. Liver steatosis was measured by shear-wave elastography using a Resona 7, Mindray ultrasound machine device. Donors were grouped by the presence of HS (0% vs. >0%, or mild HS). Differences in continuous variables were analyzed using the Independent Sample T-test. Receiver Operating Characteristic (ROC) curve analysis was performed to determine the diagnostic accuracy of 2D-SWE for HS detection.
Results: The donor cohort (N=158) had a mean age of 33.47 ± 7.74 years (32.15 ± 7.21 for males, 35.37 ± 8.12 for females, P=0.031). Histological assessment revealed that 70.3% (n=111) of donors had 0% HS, while 29.7% (n=47) had some degree of HS (5-35%). Comparison between the 'No HS group and the 'Mild HS' group showed no statistically significant differences in either SWE or blood cholesterol: mean SWE was 6.00 ± 0.75 kPa versus 5.76 ± 0.76 kPa, respectively (P=0.196); mean blood cholesterol was 4.03 ± 0.71 mmol/L versus 4.02 ± 0.65 mmol/L, respectively (P=0.977). Furthermore, ROC analysis demonstrated poor diagnostic performance for SWE in detecting mild HS, yielding an Area Under the Curve (AUC) of 0.405 (P=0.241). The optimal cut-off of 4.76 kPa (Youden method) provided a sensitivity of 0.111 and a specificity of 0.914.
Conclusion: Neither 2D-SWE-derived liver stiffness nor routine blood cholesterol was correlated with or predictive of mild hepatic steatosis in this specific cohort of healthy LDLT donors. These findings suggest that in populations with a low prevalence of advanced liver disease, such non-invasive tools may lack the necessary sensitivity to replace gold-standard biopsy for detecting mild steatosis.