Figure 2

Comparison of the CNR values in three anatomical regions. The box and whisker plots show the median (line), interquartile range (box) and internal fences (whiskers) of CNR values in each group. The paired and unpaired data sets were analysed by the Wilcoxon signed rank test (***p < 0.001) and the Mann Whitney U test (+++p < 0.001), respectively. DSA: Digital Subtraction Angiography; DVA: Digital Variance Angiography. The index shows the applied protocol, 100: normal dose (1.2 µGy/frame), 30: low-dose (0.36 µGy/frame).