Comparison of computed tomography hepatic steatosis criteria for identification of abnormal liver function and clinical risk factors, in incidentally noted fatty liver.

OBJECTIVES: Hounsfield Units (HU) to compare the various computed tomography (CT) criteria for diagnosing hepatic steatosis with laboratory liver function parameters, and clinical risk factors retrospectively, when hepatic steatosis was incidentally detected. METHODS: Institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, retrospective study in 200 randomly selected patients who had either nonenhanced CT (NECT) or contrast-enhanced CT (CECT) studies with reported hepatic steatosis. The participants were matched to age, gender, and ethnicity with 200 patients without hepatic steatosis. For NECT, four different criteria have been proposed in the literature to diagnose fatty liver: (1) liver HU less than 48 HU; (2) ratio of liver to spleen HU less than 0.8; (3) HU difference between liver and spleen less than -10; and (4) hepatic vessel HU ≥ liver HU. For CECT, difference between liver and spleen HU, in portal venous phase, ≤ -20 to -25 HU. Serum glucose, aspartate aminotransferase (AST), amino alanine transferase (ALT), total bilirubin were documented. Clinical history and clinical risk factors were documented from the electronic health records. Matched analyses and Wilcoxon signed rank sum test analysis were performed for matched variables. RESULTS: Fatty liver by NECT criteria 1 and 3 has statistically significant correlation with elevated glucose levels (P = 0.02). Similarly, fatty liver by 1, 3, and 4 NECT criteria showed statistically significant associations with higher levels of ALT and AST. There were statistically significant higher prevalence of diabetes mellitus (P = 0.003) and alcohol consumption (P ≤ 0.0001) in cases when compared with the controls. There was marginal significance in CT Dose Index between cases and controls (95% confidence interval: 0.98, 1.00; odds ratio 0.99), reflecting that cases had slightly higher BMI compared to their matched controls, thereby requiring slightly higher mA/mAs for imaging. CONCLUSION: Particular NECT criteria for fatty liver are best at identification of abnormal liver function and certain comorbidities, in the setting of incidental fatty liver detection, This creates the potential for benefits of early detection in clinical management