PURPOSE

We 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 METHODS

Twenty-one male Sprague-Dawley rats aged 7 weeks, weighing about 150g 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=101/2.9ms, flip angle 90 degrees ). Gd-DTPA (0.1mmol Gd/kg) and Gd-EOB-DTPA (0.025mmol Gd/kg) were injected at 24-h intervals, and the speed of contrast injection was 1mL/s. Signal intensities of the liver were measured and the relative enhancement (RE), the time of maximum RE (T(max)) and elimination half-life of RE (T(1/2)) in the liver were compared. The fibrosis rate (%) was calculated with the following formula: fibrosis/whole areax100.

RESULTS

The 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 T(max) and T(1/2) of each group after Gd-DTPA injection, the T(max) and T(1/2) 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 T(max) or T(1/2) after Gd-EOB-DTPA injection (r=0.90 or 0.97).

CONCLUSION

It was possible to assess the progress of liver fibrosis in NASH by evaluating the signal intensity-time course on Gd-EOB-DTPA-enhanced MRI.