[Application of dynamic contrast-enhanced magnetic resonance imaging in evaluating liver fibrosis].

Objective: To analyze the value of time-signal intensity curve (TIC) in dynamic contrast-enhanced magnetic resonance imaging (DEC-MRI) in the evaluation of liver fibrosis.

Methods: Thirty-six consecutive patients and healthy volunteers were divided into 4 groups according to the stages of fibrosis, namely the normal group (n=9), mild fibrosis group (n=5), moderate to severe fibrosis group (n=7), and liver cirrhosis group (n=15). All the subjects underwent conventional and DEC-MRI, and the TIC was generated automatically to evaluate the peak height, TTP, MSI and MSD. The correlations between the TIC parameters and the stage of fibrosis were assessed. Receiver operating characteristic (ROC) curve analyses were conducted to evaluate the value of the TIC parameters in the evaluation of fibrosis stage.

Results: Moderate but significant inverse correlations of the peak height, MSI, and to fibrosis stage were noted in these patients (P<0.05); the peak time was positively correlated to the fibrosis stage (P<0.05). In patients with a fibrosis stage ≥1, the AUC of the measured TIC parameters ranged from 0.747 to 0.783, with the MSD of the spleen had the highest AUC (0.783). For a fibrosis stage ≥3, the AUC of the indices ranged between 0.728 and 0.877, highest for liver MSI of the arterial phase, followed by the portal vein MSI, liver MSI of portal venous phase, liver MSD, splenic MSI of arterial phase and splenic MSD. In the diagnosis of liver cirrhosis, the AUC (range 0.742-0.821) decreased in the order of liver MSI of the portal venous phase, liver MSD, liver MSI of the arterial phase, the portal vein MSI, splenic MSI of the arterial phase and splenic MSD.

Conclusion: TIC of DEC-MRI can be used to evaluate hemodynamic changes in the liver, and may serve as a practical non-invasive functional imaging modality for assessing the severity of liver fibrosis.