Impact of variations in fatty liver on sonographic detection of focal hepatic lesions originally identified by CT

PURPOSE The aim of this study was to investigate the influence of variations in fatty liver on the ultrasonographic detection of focal liver lesions. METHODS A total of 229 patients with varying degrees of fatty liver and focal liver lesions and 200 patients with focal liver lesions but no fatty liver were randomly selected for inclusion in groups I and II, respectively. Findings of focal liver lesions identified on computed tomography were taken as the reference, and findings on ultrasonography were compared with them. RESULTS The number of focal liver lesions in groups I and II were 501 and 413, respectively. The ultrasonographic detection rates of focal liver lesions in groups I and II were 86.8% (435/501) and 94.2% (389/413), respectively. Comparison of the detection of the focal lesions between patients with and without fatty liver or different grades of fatty liver were as follows: mild fatty liver (162/177) vs. liver without fat infiltration (389/413) (P=0.277); mild fatty liver (162/177) vs. moderate fatty liver (190/212) (P=0.604); mild fatty liver (162/177) vs. severe fatty liver (83/112) (P<0.001); moderate fatty liver (190/212) vs. liver without fat infiltration (389/413) (P=0.051); moderate fatty liver (190/212) vs. severe fatty liver (83/112) (P<0.001); severe fatty liver (83/112) vs. liver without fat infiltration (389/413) (P<0.001); and fatty liver (435/501) vs. liver without fat infiltration (389/413) (P<0.001). CONCLUSION Mild and moderate fatty liver are not significantly associated with the visualization of the lesion, while severe fatty liver usually impairs the detection of focal lesions in the liver. If a patient with severe fatty liver is suspected to have a liver tumor, ultrasonography should only be chosen cautiously in case of a missed diagnosis.