Non-invasive steatosis assessment in NASH through the computerized processing of ultrasound images: Attenuation versus textural parameters

Ultrasonography is a simple method in diagnosing nonalcoholic steatohepatitis (NASH), providing useful information, but it is subjective and does not accurately differentiate between steatosis grades. The computerized processing of the data that comprises the ultrasonic image (CPU) might transform ultra-sonography into an objective examination. CPU can be achieved either by methods based on the study of parenchymal echogenicity and on the attenuation of the ultrasounds (attenuation and back-scattering coefficients), or by methods based on the quantification of some textural parameters. In the present paper we set out to compare the performance of the attenuation coefficient (AC) and the textural parameters derived from the GLCM matrix. 96 NASH patients and 24 healthy subjects were prospectively included in this study. We found a strong correlation between the AC and steatosis and a weak, but statistically significant one, with balooning and lobular inflammation, but not with fibrosis. The multivariate analysis showed, however, that only steatosis influences independently the AC. Of the analyzed textural parameters, only the GLCM entropy correlated weakly, but significantly, with the steatosis degree. Our study proves that the use of the attentuation coefficient computed on the ultrasonographic image can help differentiate healthy from NASH patients, as well as discriminate between various degrees of fatty load. The attenuation coefficient performs better than the textural parameters derived from the GLCM matrix. However, only GLCM entropy, of all textural parameters tested, correlates with steatosis, and even then, only for the differentiation normal vs NASH, not between steatosis grades.