Relationship between spleen volume and non-alcoholic fatty liver disease by three-dimensional computed tomography reconstruction

Objective To investigate the association of spleen volume with the risk of non-alcoholic fatty liver disease(NAFLD) as well as their causal relationship. Methods We included 90 NAFLD cases and 47 healthy controls who had received contrast-enhanced computed tomography(CT)scan of the abdomen at the Second Affiliated Hospital of Xi’an Jiaotong University from November 2022 to November 2023. We conducted three-dimensional reconstruction of the spleen through a deep learning network model using a two-stage coarse-to-fine segmentation approach. We compared the two groups using the two-sample t test or Mann-Whitney U test for continuous data and using the chi-square test for categorical data;evaluated the correlation between spleen volume and liver function indicators through Pearson correlation or Spearman rank correlation analyses;determined the factors influencing the development of NAFLD through multivariable Logistic regression analysis;and further assessed the casual relationship between spleen volume and NAFLD using the inverse variance-weighted two-sample Mendelian randomization (IVW-MR) method. Results Spleen volume was significantly larger in NAFLD cases than in controls (272.93±104.16 vs 204.37±81.20 cm³,P<0.001). The Spearman rank correlation analysis showed that spleen volume was positively correlated with the hepatic steatosis index(r_s=0.422,P<0.001)and gamma-glutamyl transferase levels(r_s=0.211,P=0.047)in patients with NAFLD. The multivariable Logistic regression analysis indicated that spleen volume was an independent risk factor for the development of NAFLD(odds ratio[OR]=1.01,95% confidence interval[CI]:1.00—1.02,P=0.049). The IVW-MR analysis detected a causal relationship between spleen volume and NAFLD(OR=1.16,95%CI:1.05—1.28,P=0.005). Conclusion Increased spleen volume may be a risk factor for the development and progression of NAFLD. Further studies are still needed to investigate the specific mechanism.