PA group & F-PCA
A significant difference in bilateral ICA diameter and flow was only found in the PA1 group with unilateral F-PCA and no contralateral PcomA. If an F-PCA was present, there was a trend for the ipsilateral ICA to have a larger diameter and higher flow volume as compared with the symmetric group (Fig. 3c, d). However, there was no significant difference between these 2 groups concerning diameter (P = 0.059) and flow volume (P = 0.085). On the other hand, the difference between ICA flow ipsilateral to the F-PCA and in the symmetric group reached statistical significance (P = 0.049) after the exclusion of 15 patients with an F-PCA with concomitant A1 asymmetry (Fig. 3e, f).