Table 1 Subjects demographic data by Circle of Willis variants All Symmetrica A1 Asymmetry (AA group)b PcomA Asymmetry (PA group)c AA1 AA2 AA3 P-value PA1d PA2 PA3 P-value Number of cases 210 81 (38.6%) 19 (9%) 33 (15.7%) 15 (7.1%) 15 (7.1%) 45 (21.4%) 18 (8.6%) Age (years) 53.9 ± 9.4 50.4 ± 9.3 52.6 ± 11.5 54.6 ± 10.1 49.9 ± 8.3 0.344 55.4 ± 7.9 53.3 ± 9.5 51.8 ± 7.0 0.507 Right-side 6 (31.6%) 8 (24.2%) 7 (46.7%) 0.311 10 (66.7%) 29 (64.4%) 14 (77.8%) 0.588 Sex  Female 77 (36.7%) 32 (39.5%) 7 (36.8%) 8 (24.2%) 4 (26.7%) 0.601 7 (46.7%) 15 (33.3%) 10 (55.6%) 0.262  Male 133 (63.3%) 49 (60.5%) 12 (63.2%) 25 (75.8%) 11 (73.3%) 8 (53.3%) 30 (66.7%) 8 (44.4%) Height (cm) 165.2 ± 8.1 165.2 ± 8.7 166.7 ± 8.2 165.5 ± 6.6 166.1 ± 6.1 0.841 163.3 ± 7.8 165.6 ± 8.7 163.4 ± 7.6 0.494 Weight (Kg) 68.0 ± 13.2 69.6 ± 14.6 69.4 ± 13.7 65.8 ± 9.9 69.7 ± 13.7 0.428 64.9 ± 11.4 67.9 ± 13.5 64.5 ± 11.0 0.543 Heart rate (/min) 67.3 ± 10.0 66.8 ± 11.1 65.8 ± 10.4 68.3 ± 8.0 65.5 ±12.6 0.551 67.8 ± 8.2 68.4 ± 7.9 69.7 ± 12/0 0.820 aSeven subjects with bilateral F-PCAs were excluded bTwenty-three patients in the AA group had PcomA asymmetry, including 2 PA1, 14 PA2, and 7 PA3 cTwenty-three patients in the PA group had A1 asymmetry, including 5 AA1, 13 AA2, and 5 AA3 dThirty-seven subjects with 45 F-PCA, with 20 right-side F-PCA, 9 left-side F-PCA, and 8 bilateral F-PCAs