New proposal for the staging of nonalcoholic steatohepatitis: Evaluation of liver fibrosis on Gd-EOB-DTPA-enhanced MRI

PurposeWe investigated whether the gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI was useful for nonalcoholic steatohepatitis (NASH) staging based on the severity of liver fibrosis.Materials and methodsTwenty-one male Sprague–Dawley rats aged 7 weeks, weighing about 150 g in NASH group were fed a choline-deficient diet for 4, 7 or 10 weeks, and seven rats in the control group were fed a standard diet (n = 7). After the feeding period, the rats were subjected to contrast-enhanced MRI (2D-FLASH; TR/TE = 101/2.9 ms, flip angle 90°). Gd-DTPA (0.1 mmol Gd/kg) and Gd-EOB-DTPA (0.025 mmol Gd/kg) were injected at 24-h intervals, and the speed of contrast injection was 1 mL/s. Signal intensities of the liver were measured and the relative enhancement (RE), the time of maximum RE (Tmax) and elimination half-life of RE (T1/2) in the liver were compared. The fibrosis rate (%) was calculated with the following formula: fibrosis/whole area × 100.ResultsThe fibrosis rates of each group were as follows: 0.52, 0.79, 2.84, and 0.50% (4, 7, 10 weeks and control groups). The fibrosis rate of the 10 weeks group was significantly higher than the control and 4 or 7 weeks groups. Although there was no difference between the Tmax and T1/2 of each group after Gd-DTPA injection, the Tmax and T1/2 of the 10 weeks group were significantly prolonged in comparison with the control and 4 or 7 weeks groups after Gd-EOB-DTPA injection (p < 0.01). There was a significant correlation between the fibrosis rate and Tmax or T1/2 after Gd-EOB-DTPA injection (r = 0.90 or 0.97).ConclusionIt was possible to assess the progress of liver fibrosis in NASH by evaluating the signal intensity-time course on Gd-EOB-DTPA-enhanced MRI.