Average signal intensity (ASI) values of root samples that treated with different concentrations of Gd-DTPA at all four different time points. LiuZan QianJunchao LiuBinmei WangQi NiXiaoyu DongYaling ZhongKai WuYuejin 2014 <p>Average signal intensity (ASI) values of root samples that treated with different concentrations of Gd-DTPA at all four different time points.</p>