Liver Focal Fatty Change Evaluated by Contrast-Enhanced Ultrasound: A Retrospective Study in an Ultrasound Expert Center

Abstract

The goal of this paper was to evaluate the liver focal fatty change (either fat infiltration or fatty sparing) assessed by contrast-enhanced ultrasound (CEUS), in a tertiary center. A retrospective study was performed that evaluated a cohort of 2904 de novo focal liver lesions (FLLs) assessed by CEUS (according to EFSUMB guidelines) over a period of seven years (2010-2016). Focal fatty change (FFC) lesions that were referred for contrast assessment were 319/2904 (11%). From 2904 FLLs, 979 (33.7%) were also evaluated by a second line imaging technique or histology (due to the incomplete EFSUMB diagnostic pattern criteria). We evaluated the sensitivity, specificity and accuracy of CEUS for the FFC that were confirmed by a second line imaging technique (CT, MRI) or histology. For the statistical analysis we used OpenEpi software. From 2904 de novo FLLs, 319 (11%) were FFC, in female 46.4%, in male 53,6%; mean age 54.3+/- 11.9 years, mean lesion size: 3.37±2.13 cm. 233/319 (73%)- were fatty sparing and 86/319 (27%)-fat infiltration. FFC represented by focal infiltration were diagnosed on liver with chronic hepathopaty: 25/319 (7.8%) and 61/319 (92.8%) on liver without fibrosis. CEUS was conclusive (lesions with typical enhancement pattern as presented in EFSUMB guidelines) for the diagnosis of FFC in 97.2% of cases. From 979 FLLs group (CT, MRI or histology for the final diagnosis), 31/979 (3.2%) were FFC. 22/31 (71%) were fatty sparing and 9/31 (29%) were fat infiltration. CEUS performance in the diagnosis of FFC was: 72.73% Sensitivity; 99.67% Specificity; 98.28% Accuracy. The performance of CEUS was influenced by the diameter of the lesion (>5cm) and the presence of sever fibrosis ≥F3. CEUS is an accurate and specific method for the diagnosis of focal fatty changes; still the results can be influenced by the size of the lesion and the presence of liver cirrhosis.