Evaluation of the relationship between density values of liver parenchyma and liver function tests in non-contrast computed tomography

Aim In normal healthy individuals, liver parenchyma density varies between 50-65 Hounsfield unit (HU) on nonenhanced computed tomography (NECT). In the presence of hepatosteatosis, liver parenchymal density values decrease according to the degree of steatosis, and abnormalities can be seen in liver function tests. In our study, we used for detecting moderate or severe hepatosteatosis criteria were liver parenchyma density being 40 HU or less, liver parenchymal density to spleen parenchymal density ratio being 0.8 or less, liver parenchymal density and spleen parenchymal density difference being -10 or below on NECT. Our aim with this study is to determine the prevalence of hepatosteatosis. Comparison of age, gender distribution and adiposity between liver lobes in individuals with hepatosteatosis. Compare alanine transaminase (ALT), aspartate transaminase (AST), gamma glutamyl transferase (GGT), ALT/AST values between the group with hepatosteatosis and the group without hepatosteatosis. Materials and Methods Individuals whose liver function tests AST, ALT and GGT parameters were studied within a maximum of 24 hours with CT scan were included in the study. Density measurements were made by manually drawing circular ROI from the liver segments 3, 4b, 5, 6 levels and the upper, middle and lower parts of the spleen on the NECT images. Liver function tests are documented along with density measurements. Results A total of 1028 individuals were included in the study. Individuals with liver density ≤ 40 HU mean AST 38.29±14.85, ALT 47.15±19.92, GGT 50.22±28.79, ALT/AST 1,29 values were found. Individuals with liver density > 40 HU mean AST 21.77±8.26, ALT 18.27±8.74, GGT 20.76±13.65, ALT/AST 0, 86 values were found. Age, ALT, AST, GGT and ALT/AST mean scores of individuals with liver density/spleen density ≤ 0.8 were found to be significantly higher compared to individuals with liver density/splenic density >0.80. The averages of age, ALT, AST, GGT and ALT/AST were found to be significantly higher in individuals with liver density - spleen density ≤ -10 compared to individuals with liver density - spleen density ˃ -10. Conclusions According to the 3 criteria we used to detect hepatosteatosis in unenhanced CT, the prevalence of hepatosteatosis was found to be %14.49 , %12.45 and %12.54 , respectively. The frequency of female gender and advanced age was found to be high in the hepatosteatosis group, valid for each of the 3 criteria we used to detect hepatosteatosis. It was determined that the right lobe of the liver was more fatty than the left lobe in the hepatosteatosis group, valid for each of the 3 criteria we used to detect hepatosteatosis. The mean values of ALT, AST, GGT, ALT/AST in the group with hepatosteatosis were found to be significantly higher than the group without hepatosteatosis, valid for all 3 criteria. ALT, AST, GGT, ALT/AST mean values were found to decrease as the liver parenchyma density value goes from the lowest to the highest group. An inverse correlation was found between the liver parenchyma density values and the mean values of ALT, AST, GGT, ALT/AST between the groups. Keywords: Nonenhanced CT, hepatic steatosis, fatty liver, liver function test, alanine transaminase