Objective  To explore the value of abdominal fat CT quantitative parameters combined with the CT value ratio of liver to spleen (CT_L/S) in evaluating the degree of hepatic steatosis and risk of concomitant carotid atherosclerosis (CAS) plaques in patients with non-alcoholic fatty liver disease (NAFLD).

Methods  A prospective study was conducted, and 180 patients with NAFLD (observation group) admitted to Yangquan First People's Hospital from January 2019 to January 2022 were selected. They included 96 males and 84 females aged (64.6±6.9) years with ages that ranged from 35 years to 78 years. A total of 45 healthy subjects (control group) were selected from the physical examination center of Yangquan First People's Hospital during the same period. They included 25 males and 20 females aged (64.3±5.1) years with ages that spanned 33 years to 79 years. Abdominal CT examination was performed on both groups. The carotid intima-media thickness (IMT) of patients in the observation group was measured, and the observation group was divided into groups with NAFLD combined with CAS plaques (IMT≥1.2 mm) or NAFLD alone (IMT<1.2 mm) on the basis of IMT results. CT_L/S, visceral fat area (VFA), total fat area (TFA), sagittal diameter at the umbilical level (hereinafter referred to as sagittal diameter), and intermuscular fat area (IMFA) were compared between the observation and control groups. CT_L/S, VFA, TFA, sagittal diameter, IMFA, and degree of hepatic steatosis were compared between NAFLD combined with CAS plaques group and NAFLD alone group. Measurement data between two groups were compared by t test, while counting data were compared by χ² test. Multivariate Logistic regression analysis was used to identify independent risk factors for NAFLD combined with CAS plaques, and receiver operating characteristic (ROC) curves were applied to analyze its diagnostic value for NAFLD combined with CAS plaques, and Spearman's method was employed to analyze its correlation with the degree of hepatic steatosis in patients with NAFLD.

Results  The CT_L/S of the observation group was significantly lower than that of the control group (0.59±0.10 vs. 0.86±0.12; t=15.539, P<0.001). The VFA ((173.80±22.42) cm² vs. (139.82±21.46) cm²), TFA ((407.23±41.82) cm² vs. (365.71±36.85) cm²), and sagittal diameter ((22.90±1.55) cm vs. (20.06±1.47) cm) of the observation group were significantly higher than those of the control group (t=9.273, 6.200, 11.237, all P<0.001). The CT_L/S (0.49±0.12 vs. 0.63±0.15) and proportion of mild hepatic steatosis (35.29% vs. 66.67%) in patients of NAFLD combined with CAS plaques group were significantly lower than those in patients of NAFLD alone group (t=5.952, χ²=14.746, both P<0.001). VFA ((190.69±24.17) cm² vs. (167.13±22.15) cm²), TFA ((442.17±46.22) cm² vs. (393.42±40.87) cm²), sagittal diameter ((24.80±2.04) cm vs. (22.15±1.81) cm), and the proportion of severe hepatic steatosis (33.33% vs. 11.63%) in patients of NAFLD combined with CAS plaques group were significantly higher than those in patients of NAFLD alone group (t=6.265, 6.944, 8.533, χ²=11.780, all P<0.001). Multivariate Logistic regression analysis results showed that CT_L/S (OR=2.537, 95%CI: 1.412–4.659), VFA (OR=1.225, 95%CI: 1.101–2.460), TFA (OR=1.354, 95%CI: 1.025–3.074), and sagittal diameter (OR=3.815, 95%CI: 2.030–7.172) were all independent risk factors for NAFLD combined with CAS plaques (all P<0.05). The results of ROC curve analysis revealed that the combination of CT_L/S, VFA, TFA, and sagittal diameter had the largest area under the curve for the diagnosis of NAFLD combined with CAS plaques (0.963) and showed a sensitivity of 84.31% and specificity of 97.67%. The CT_L/S of patients with NAFLD was negatively correlated with the degree of hepatic steatosis (r=−0.571, P<0.001), and VFA, TFA, and sagittal diameter were all positively correlated with the degree of hepatic steatosis (r=0.635, 0.317, and 0.622, all P<0.001).

Conclusion Abdominal fat CT quantitative parameters and CT_L/S are closely related to the degree of hepatic steatosis in patients with NAFLD, and the combined detection of CT_L/S, VFA, TFA, and sagittal diameter may have certain potential value in distinguishing NAFLD combined with CAS plaques.