Fig 1.

The distribution of group 1, 2, and 3 aneurysms and the 3 ranges (0°–29°, 30°–59°, 60°–90°) of the angle of the section plane that identified the aneurysm orifice with respect to the imaging section direction on 3D TOF MRA (group 1, the location of the inflow zone was in accord on 4D flow MR imaging and transluminal color-coded 3D MRA scans; group 2, the location of the inflow zone was on the contralateral side of the neck; group 3, the location of the inflow zone was undefined). There was a significant difference in the distribution among the angle ranges (P = .018). Of 11 aneurysms with the 0°–29° angle range, 10 (90.9%) were assigned to group 1; and the others, to group 3 (P = .072, compared with the other angle ranges).