This study was undertaken to evaluate an image processing method for assessing liver fibrosis in conventional computed tomography (CT) scans in patients with chronic hepatitis C. Two cohorts (designated "estimation," n = 34; and "validation," n = 107) of chronic hepatitis C patients were assessed using digitized conventional helical CT. Weighted CT mean fibrosis (Fibro-CT) was calculated as a nonlinear weighted mean F-score for each sample. Fibrosis was defined according to Scheuer on the F0 to F4 scale by 2 pathologists blinded regarding the Fibro-CT data. Fibrosis according to Fibro-CT correlated with histology-determined fibrosis (r = 0.69; P < 0.001) and with increasing F-stage: F0 = 0.23 +/- 0.39; F1 = 0.90 +/- 0.99; F2 = 1.41 +/- 0.94; F3 = 2.79 +/- 0.55; F4 = 3.15 +/- 0.35 [analysis of variance: P < 0.0001). The receiver operating characteristics curve to diagnose significant fibrosis (>/=F2) was 0.83; 95% confidence interval (95%CI), 0.75 to 0.91; and, to diagnose advanced fibrosis (>/=F3), was 0.86, 95%CI: 0.80 to 0.93. The correlation between Fibro-CT and fibrosis was higher in patients with homogeneous distribution of fibrosis than in patients with heterogeneous distribution (r = 0.77 versus r = 0.43; P < 0.05).
Conclusion: Optical digital analysis of CT images of the liver is effective in determining the stage and distribution of liver fibrosis in chronic hepatitis C. In patients with homogeneous fibrosis distribution, the correlation between Fibro-CT and histology was better than in patients with heterogeneous distribution. Fibro-CT is a simple to use, readily available, and useful method for the diagnosis of fibrosis in patients with chronic hepatitis C.