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


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).


CONCLUSIONS
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.
Tsuda
Natsuko
N
Medical Affairs Diagnostic Imaging, Medical Affairs, Bayer Yakuhin, Ltd. 2-4-9, Umeda, Kita-ku, Osaka 530-0001, Japan.
Okada
Masahiro
M
Murakami
Takamichi
T
D000437:Alcoholism / Q000150:complications / Q000175:diagnosis; D000818:Animals; D003287:Contrast Media; D005234:Fatty Liver / Q000150:complications* / Q000175:diagnosis*; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008103:Liver Cirrhosis / Q000150:complications* / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010865:Pilot Projects; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA