Table 2 Comparison of the morphometric parameters for the MCA bifurcation among the patient groups

α angle (^o)

128.2 ± 24.2

105.9 ± 19.1

103.4 ± 25.8

93.3 ± 18.0

97.1 ± 20.5

93.2 ± 19.6

< 0.001

Φ₁ angle (^o)

59.6 ± 25.2

47.3 ± 20.9

47.7 ± 23.0

49.9 ± 27.0

46.8 ± 23.1

42.4 ± 23.0

< 0.001

Φ₂ angle (^o)

81.5 ± 21.7

68.2 ± 20.4

66.4 ± 20.5

57.8 ± 25.2

61.0 ± 19.4

65.3 ± 18.2

< 0.001

r₀, mm

1.40 ± 0.18

1.42 ± 0.18

1.54 ± 0.21

1.49 ± 0.25

1.35 ± 0.16

1.31 ± 0.20

< 0.001

r₁, mm

1.16 ± 0.17

1.17 ± 0.19

1.24 ± 0.23

1.21 ± 0.23

1.15 ± 0.18

1.11 ± 0.21

NS

r₂, mm

0.87 ± 0.20

0.91 ± 0.19

0.95 ± 0.22

0.94 ± 0.18

0.86 ± 0.17

0.84 ± 0.18

NS

asymmetry ratio, r₂²r₁^− 2

0.60 ± 0.24

0.63 ± 0.21

0.56 ± 0.20

0.65 ± 0.17

0.59 ± 0.21

0.61 ± 0.20

NS

area ratio, (r₁²+r₂²)r₀^− 2

1.10 ± 0.20

1.11 ± 0.24

1.11 ± 0.17

1.10 ± 0.25

1.15 ± 0.21

1.15 ± 0.23

NS

n, junction exponent

2.49 ± 0.93

2.69 ± 1.19

2.56 ± 0.84

2.65 ± 1.20

2.84 ± 1.11

2.79 ± 1.06

NS

(ϕ₁ + ϕ₂) - α angle (^o)

− 68.6 ± 29.7

−38.8 ± 30.5

−36.7 ± 34.1

−32.0 ± 24.7

− 28.2 ± 25.1

−30.0 ± 35.8

< 0.001

ϕ₁ - Φ₁ angle (^o)

−38.6 ± 24.4

− 23.7 ± 21.0

− 26.4 ± 25.7

− 25.1 ± 21.8

− 23.1 ± 23.3

− 21.1 ± 26.6

< 0.001

ϕ₂ - Φ₂ angle (^o)

−42.7 ± 27.3

−25.6 ± 22.8

− 24.0 ± 21.3

− 20.5 ± 27.1

− 16.0 ± 22.3

−23.3 ± 25.9

< 0.001