Non-invasive assessment of liver steatosis in non-alcoholic fatty liver disease

Aim The diagnosis of non‐alcoholic fatty liver disease (NAFLD) is based on the histological findings. Further, there may be interobserver differences. Liver to spleen (L/S) ratio on computed tomography (CT) is employed to detect or even quantify the fat content of the liver. The objective of this study was to accurately diagnose fatty liver by evaluating the relationship between L/S ratio and histological findings. Methods Sixty‐seven biopsy‐proven NAFLD patients were enrolled. L/S ratio on CT was calculated. The area of steatosis in liver specimens was measured by BIOREVO BZ‐9000 microscope, and the percentage of steatosis was calculated using Dynamic cell count BZ‐H1C software. Results Steatotic grade assessed by pathologist was significantly correlated with the percentage of steatosis and L/S ratio. Factors associated with steatosis were L/S ratio, aspartate aminotransferase and Homeostasis Model of Assessment – Insulin Resistance as determined by multivariate analysis. L/S ratios were: S0, 1.16 ± 0.20 (mean ± standard deviation); S1, 0.88 ± 0.28; S2, 0.76 ± 0.20; and S3, 0.40 ± 0.18, respectively. The optimal cut‐off value of L/S ratio to exclude steatosis was 1.1, and the area under the receiver–operator curve for the diagnosis of steatosis was 0.886. Conclusion Our study suggests that while 0% of steatosis showed 1.296 L/S ratio, the cut‐off value of L/S ratio would be 1.1 at least to exclude clinically important liver steatosis.