B-Mode Ultrasound With Algorithm Based on Statistical Analysis of Signals: Evaluation of Liver Fibrosis in Patients With Chronic Hepatitis C

Abstract

The purpose of this study was to evaluate the degree of liver fibrosis in patients with chronic hepatitis C by use of a method in which the homogeneity of the tissue texture of the liver on B-mode ultrasound images is analyzed on the basis of results of a statistical chi-square test of the echo amplitudes. The method includes an algorithm for removing small structures, such as cross sections of the thin vessels, in the background texture to minimize differences in analysis results between users. Analysis was performed on images of 148 patients with histologically proven chronic hepatitis C without cirrhosis. The peak value of the C(m)(2) (modified chi-square distribution) histogram was calculated from B-mode ultrasound images, and the resulting value was compared with the histologic fibrosis grade. The peak C(m)(2) histogram value for grade F3 fibrosis was higher than that for grades F0 and F1 (p < 0.0001) and F2 (p = 0.0003). The value for grade F2 was higher than that for grades F0 and F1 (p = 0.0027). The values gradually increased with an increase in liver fibrosis grade, although no difference was found between grades F0 and F1. The grades of liver fibrosis in patients with chronic hepatitis C are well discriminated with the B-mode ultrasound-based analysis algorithm without discrimination between grades F0 and F1. Findings on conventional ultrasound images may reflect progression of liver fibrosis even in the absence of cirrhosis.