Noninvasive assessment of hepatic fibrosis using gadoxetate-disodium-enhanced 3T MRI

Introduction. Gadoxetate-disodium is a liver-specific MR contrast agent absorbed by hepatocytes via organic anion transporting polypeptide 1B3 and is excreted into the biliary system by multidrug resistance-associated protein 2. It has been suggested that relative parenchymal enhancement on hepatocyte phase image is associated with hepatic function. However, it is not clear whether gadoxetate-disodium-enhanced MRI can be used as a noninvasive fibrosis marker. Thus, the purpose of our study was to evaluate the diagnostic performance of gadoxetate-disodium-enhanced MRI in predicting the hepatic fibrosis stage. Materials and methods. A total of 113 patients who had fibrosis staged according to the Batts and Ludwig score were enrolled: F0 (n = 13), F1 (n = 18), F2 (n = 15), F3 (n = 32), and F4 (n = 35). All patients underwent gadoxetate- disodium-enhanced MRI before confirmation by biopsy (n = 67) or surgery (n = 46). For quantitative analysis, the contrast enhancement index (CEI) was calculated by measuring the signal intensity (SI) in liver and paraspinal muscle using a region of interest, as follows: CEI = (liver SI/paraspinal muscle SI)_{20 min hepatocyte phase image}/(liver SI/paraspinal muscle SI)_{pre-contrast T1-weighted image}. The diagnostic performance was evaluated by the ROC curve, adjusted for the prevalence of each fibrosis stage. Results. A significant negative correlation was observed between CEI and fibrosis stage (r = -0.545, P < 0.0001). The adjusted AUROC for CEI in the prediction of mild (≥ F1), moderate (≥ F2), or severe fibrosis (≥ F3) and liver cirrhosis (F4) was 0.668, 0.703, 0.73, and 0.84, respectively. In conclusion, our results demonstrate that quantitative analysis of relative hepatic enhancement using gadoxetate-disodium-enhanced MRI can predict the hepatic fibrosis stage.