Measurement of spleen volume is useful for distinguishing between simple steatosis and early‐stage non‐alcoholic steatohepatitis

Aim: Although non‐alcoholic fatty liver disease (NAFLD) is now a common cause of chronic liver disease, discriminating between simple steatosis and non‐alcoholic steatohepatitis (NASH), especially early‐stage NASH, remains difficult. We investigated the clinical usefulness of measuring the spleen volume as a marker of early‐stage NASH. Methods: We evaluated computed tomography (CT) images obtained in 84 patients with histologically diagnosed NAFLD (22 with simple steatosis, 62 with NASH with mild fibrosis [stages 1–2]). We defined the data obtained by the following formula as a spleen‐body index (SBI): SBI = maximal CT axial section area of the spleen (cm²)/body surface area (BSA) (cm²) × 10⁴. We compared the SBI between patients with simple steatosis and those with NASH with mild fibrosis. Results: The mean SBI of the simple steatosis group was 15.8 ± 3.9, while that of the NASH with mild fibrosis group was 18.7 ± 5.7. This difference between the two groups was significant (P = 0.0314). A multiple logistic regression analysis showed that the SBI was significantly correlated with the discrimination of simple steatosis and NASH with mild fibrosis. The area under the receiver–operator curve was 0.661 for distinguishing between simple steatosis and NASH with mild fibrosis (P = 0.026, 95% confidence interval = 0.532–0.789). Conclusion: Spleen enlargement may be a distinct feature of NASH, especially early‐stage NASH. SBI might be a non‐invasive and simple method of differentiating NASH and simple steatosis.