Diffusion-weighted magnetic resonance imaging for the assessment of fibrosis in chronic hepatitis C.

UNLABELLED: Liver biopsy is the gold standard for assessing fibrosis but has several limitations. We evaluated a noninvasive method, so-called diffusion-weighted magnetic resonance imaging (DWMRI), which measures the apparent diffusion coefficient (ADC) of water, for the diagnosis of liver fibrosis in patients with chronic hepatitis C virus (HCV). We analyzed 20 healthy volunteers and 54 patients with chronic HCV (METAVIR: F0, n = 1; F1, n = 30; F2, n = 8; F3, n = 5; and F4, n = 10) prospectively included. Patients with moderate-to-severe fibrosis (F2-F3-F4) had hepatic ADC values lower than those without or with mild fibrosis (F0-F1; mean: 1.10 +/- 0.11 versus 1.30 +/- 0.12 x 10(-3) mm2/s) and healthy volunteers (mean: 1.44 +/- 0.02 x 10(-3) mm2/s). In discriminating patients staged F3-F4, the areas under the receiving operating characteristic curves (AUCs) were 0.92 (+/-0.04) for magnetic resonance imaging (MRI), 0.92 (+/-0.05) for elastography, 0.79 (+/-0.08) for FibroTest, 0.87 (+/-0.06) for the aspartate aminotransferase to platelets ratio index (APRI), 0.86 (+/-0.06) for the Forns index, and 0.87 (+/-0.06) for hyaluronate. In these patients, the sensitivity, specificity, positive predictive value, and negative predictive value were 87%, 87%, 72%, and 94%, respectively, with an ADC cutoff level of 1.21 x 10(-3) mm2/s. In discriminating patients staged F2-F3-F4, the AUC values were 0.79 (+/-0.07) for MRI, 0.87 (+/-0.05) for elastography, 0.68 (+/-0.09) for FibroTest, 0.81 (+/-0.06) for APRI, 0.72 (+/-0.08) for the Forns index, and 0.77 (+/-0.06) for hyaluronate.
CONCLUSION: This preliminary study suggests that DWMRI compares favorably with other noninvasive tests for the presence of significant liver fibrosis.