Abstract:【Abstract】 Objective Magnetic resonance (MR) portovenography standardized by the time to peak (TTP) of portal vein obtained from dynamic contrastenhanced scans, and determine whether the calibers of the main portal vein as well as its principal branches shown on the standard MR portovenography could identify hepatic fibrosis and cirrhosis.Methods 16 minipigs were prospectively used to model liver fibrosis and cirrhosis, and underwent MR dynamic contrastenhancement scans on 0, 5th, 9th, 16th and 21st weekend after the beginning of modeling the disease to obtain TTP of portal vein, and standard MR portovenography was subsequently carried out based on the TTP. On the axial portovenography, diameters of main portal vein (MPV), superior mesenteric vein (SMV) or splenic vein (SPV) were measured. The range of TTP was statistically obtained for the standard scan time of MR portovenography in hepatic fibrosis and cirrhosis. Diameters of the above veins were statistically analyzed to determine how to determine hepatic fibrosis and cirrhosis.Results From hepatic normality to fibrosis and to cirrhosis, the values of TTP (r=0.714), and the diameters of MPV (r=0.402), SMV (r=0.33) and SPV (r=0.644) increased (all P<0.05), and the diameters of SPV increased more greatly than any other diameter. For standard MR portovenography in hepatic fibrosis and cirrhosis, the cutoff of TTP was 34.45 s and 39.15 s, respectively. For diagnosis of hepatic fibrosis, the areas under receiver operating characteristic (ROC) curves of MPV, SMV and SPV were 0.696, 0.711 and 0.848, respectively. For diagnosis of cirrhosis, the areas under ROC curves of MPV, SMV and SPV were 0.733, 0.631 and 0.861, respectively. The diameter of SPV could be the better index for diagnosis of hepatic fibrosis and cirrhosis than any other diameter (all P<0.05).Conclusions The TTP of portal vein on dynamic contrastenhanced MR scans could standardize MR portovenography, and the diameter of SPV could be a recommended indicator for detecting hepatic fibrosis and liver cirrhosis.