Assessment of aquaporins function of early-stage liver fibrosis using multi-b diffusion weighted magnetic resonance imaging
LI Qiu-ju1, LI Jia-hui1, ZHAO Zhou-she2, YU Bing1, SHI Yu1, GUO Qi-yong1
1. Department of Radiology, Shengjing Hospital of China Medical University, Shenyang 110004, China;2. General Electronic Company Healthcare(China), Beijing 100176, China
Abstract： Objective: To investigate the value of aquaporins(AQP) function in the diagnosis of early liver fibrosis by using multiple b-value(multi-b) diffusion weighted magnetic resonancce imaging(MR-DWI). Methods: Using acetazolamide as AQP inhibitor, rats of control group and rats of developed model of liver fibrosis undertook conventional MR scans and a multi-b DWI before and after inhibition. The DWI was carried out with 18 different b values selected from 0 to 4 500 s/mm2. First of all, we obtained the standard ADC value in accordance with conventional methods, and then the multi-b values were divided into low-b, middle-b and high-b domains with 200 s/mm2 and 1 500 s/mm2 as thresholds. According to histological fibrosis stage, rats were divided into four groups: S0, S1, S2, S3+S4. With multiple b values, the result of apparent diffusion coefficience(ADC) and the expression and activity of AQP in four groups were compared. Results: There was no significant difference between each group in standard ADC. The AQP1 expression in the liver endothelial cells significantly increased with aggravation of liver fibrosis in early stage. Before inhibition, significant difference was observed between S0 and S3+S4 at high b value. While after inhibition, each group could be distinguished except S0 and S1. The high-b ADC value decreased 15.5% at S0, 16% at S1, while no obvious decrease was observed at S2 with the addition of inhibitor. The inhibition rate increased to 11.7% at S3+S4. Conclusion: Our preliminary experimental results indicate that the standard ADC value obtained by conventional method can not detect and stage early liver fibrosis, while the high-b ADC values are correlated with AQP expression, so the multi-b MR-DWI technique is capable to detect and stage early liver fibrosis.
2014, Vol. 25 
