Non-invasive Steatosis Assessment through the Computerized Processing of Ultrasound Images: Attenuation versus First Order Texture Parameters

Steatosis is a frequent histological finding in patients with chronic hepatitis C virus (VHC) infection. Usual ultrasonography (US) cannot accurately detect the steatosis grade, nor can it always discriminate between steatosis and fibrosis. An improvement of usual US examination is currently under research. A possible approach might be the computerized processing of the data comprised in the US image. In the present paper we set out to compare the performance of two computerized methods for the steatosis assessment on the US images: the attenuation coefficient and the first order textural parameters (FO): Mean, Standard Deviation and Skewness. The attenuation coefficient correlated significantly with steatosis (r=-0.444, p<0.0001), but not with fibrosis (r=-0.046, p=0.395) or necroinflammatory activity (r=-0056, p=0.211). Of the FO parameters, only the FO mean correlated significantly with steatosis (r=0.300, p<0.0001), but also with necroinflammatory activity (r=0.128, p=0004). The present study proves that, in patients having chronic hepatitis C, the attenuation coefficient, but also the FO mean, can discriminate between different steatosis grades; however, the attenuation coefficient has a better performance than the FO mean, being influenced only by steatosis, not by fibrosis or necroinflammatory activity. The area under the ROC curve is significantly better for the attenuation coefficient as compared to the FO mean for the prediction of steatosis regardless of the grade (0.741 vs 0.652, p=0.001), as well as for the prediction of moderate/severe steatosis (0.791 vs 0.719, p=0.043).