Differentiation between true focal liver lesions and pseudolesions in patients with fatty liver: evaluation of helical CT criteria.

Abstract

To determine the potential of helical CT for differentiating true lesions from pseudolesions in patients with fatty liver. Helical CT of 44 patients with diffuse fatty liver (22 with true lesions; 22 with pseudolesions) were reviewed by two observers with regard to morphological features of visible lesions. Univariate analysis was used to detect discriminating criteria for the diagnosis of true lesions. Interobserver agreement was excellent for 9/10 morphological criteria (kappa = 0.831-1). True lesions were more frequently distant from the liver capsule (50.00% vs. 4.55%), located in the right lobe (72.73% vs. 31.82%), round (86.36% vs. 54.55%), heterogeneous (27.27% vs. 0.00%) and had ill-defined margins (40.91% vs. 13.64%) compared with pseudolesions (P < 0.05). Using univariate analysis, a location distant from the liver capsule was the most discriminating variable to differentiate between true and pseudolesions (P = 0.0060). Hyperattenuating content and round shape were the most sensitive criteria (sensitivity = 90.91% and 86.36%, respectively) for the diagnosis of true lesions, and heterogeneity, vascular displacement and encapsulation were the three most specific ones (specificity = 100.00%). Best accuracy was obtained with an association of the three variables (accuracy = 86.36%). Helical CT provides objective and discriminating morphological criteria to differentiate between true lesions and pseudolesions in patients with fatty liver.