Correlation of ultrasound attenuation and histopathological parameters of the liver in chronic diffuse liver diseases

Abstract

OBJECTIVE: In patients with chronic diffuse liver diseases two characteristic ultrasound patterns of bright liver, the low (DI) and the high (DII) attenuation types, are seen. Correlation was studied between liver attenuation and histopathological analysis of biopsy specimens of the same patients. METHODS: Ultrasound attenuation of the liver was measured quantitatively using a homogeneous tissue-equivalent reference phantom. Semiquantitative scores were used for histopathological analysis of biopsy specimens. RESULTS: One hundred and twenty-two patients were investigated; 40 of them showed a normal liver echopattern. The average attenuation was 0.68+/-0.03 dB/cm per MHz. Histopathological parameters were normal in most of the patients, except for four cases where a minimal amount of collagen and 14 cases where a subtle amount of lipid content could be detected, in three cases accompanied by some cells indicating inflammation. From 82 patients with bright liver, 47 showed the DI type. The average attenuation was 0.80+/-0.03 dB/cm per MHz. In all of these patients, significant increases of collagen content and inflammatory reaction were found. In 23 cases a negligible amount of lipid deposition could also be revealed. Thirty-five patients exhibited a DII-type bright liver. The average attenuation was 1.21+/-0.06 dB/cm per MHz. A significant amount of lipid deposition was detected in all cases. In 13 patients a minimal amount of collagen and in 14 patients some inflammatory cells were detected. CONCLUSIONS: In livers with a normal echopattern, none or minimal pathological changes were seen. In DI-type bright liver, connective tissue dominance exists, in DII-type bright liver lipid deposition dominance. On this basis it is proved that the diagnosis of a fatty liver can be established without biopsy, if no other indication for biopsy exists.