Abstract: Objective To investigate the diagnostic value of Gd-EOB-DTPA enhanced MRI T1-mapping in grading the severity of liver fibrosis. Methods A total 149 patients who have underwent Gd-EOB-DTPA enhanced MRI T1-mapping scans and then hepatectomy were enrolled. T1 relaxation time before and 5, 10, and 15 minutes after bolus of contrast agent and ishak fibrosis score of Liver tissue surrounding the lesion were obtained. The differences in T1 relaxation time between cases with different fibrosis scores and the diagnostic ability to use T1 relaxation time to grade the severity of liver fibrosis were statistically analyzed. Results The differences in T1 relaxation time among patients with different fibrosis scores were statistically significant in each phase of the scan. Among them, the difference in T1 relaxation time was the largest at 15 min after enhancement. After pairwise comparison, there were statistically significant differences between groups 0 and 5 (P=0.007), group 0 and 6 (P<0.001), group 1 and 6 (P=0.001), group 2 and 6 (P=0.002), and group 3 and 6 (P=0.008). Using ROC curve analysis, T1 relaxation time obtained from T1-mapping acquired 15-minute after enhancement outperformed others with largest area under the curve, specifically in which the area under the ROC curve for patients with fibrosis score >0, >1, >2, >3, >4 and >5 were 0.727, 0.736, 0.697, 0.708, 0.703, and 0.720, respectively. Conclusion T1 relaxation time can be used to evaluate the severity of fibrosis in patients, and particularly, the T1 relaxation time of 15 minutes after enhancement has the best diagnostic efficacy.

Key words: Gadoxetic acid disodium injection, Liver fibrosis, T1 relaxation time, Magnetic resonance imaging