A pilot approach for quantitative assessment of liver fibrosis using ultrasound: preliminary results in 79 cases

Background/Aims Ultrasound is noninvasive and useful to evaluate liver disease despite its operator dependency. This pilot study was conducted to quantitatively assess liver fibrosis using ultrasound. Methods Fibrosis extraction ratios (FER) (fiber volume/total volume) of ultrasound and histological images of 8 autopsy specimens were compared. We also compared FER of ultrasound images from clinical patients (n=79) with histological fibrosis stages. Results In the autopsy study, FER correlation coefficient between histological images and ultrasound images was 0.992. Regarding clinical patients, there was sufficient evidence to indicate differences in the distributions of FER for each fibrosis stage (Kruskal–Wallis test P<0.0001). With FER cut-off to distinguish ≥F2 from F0 and F1 defined as mean plus standard deviation of F0 and F1, sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio were 62, 75, 78, 57%, and 2.47, respectively. Regarding HCV cohort (n=44), they were 55, 87, 89, 50%, and 4.14, respectively. Areas under receiver operating characteristic curves were 0.78, 0.79, 0.83 and 0.83 for ≥F1, ≥F2, ≥F3 and =F4, respectively. Regarding HCV cohort, they were 0.74, 0.71, 0.79 for ≥F2, ≥3 and =4, respectively. Conclusions The FER method has great potential for diagnosing liver fibrosis using ultrasound.