Right

Midline

Left

Total

Anterior cerebral artery

Anterior communicating artery

Proximal to anterior communicating

Pericallosal

Subtotal

3

4

7

33

33

3

3

6

33

6

7

46

Internal carotid artery

Proximal or ophthalmic region

Posterior communicating region

Bifurcation

Cavernous internal carotid

Subtotal

1

25

2

1

29

3

17

20

4

42

2

1

49

Middle cerebral artery

Bifurcation

Distal to main bifurcation

Subtotal

16

3

19

10

2

12

26

5

31

Posterior circulation

Basilar bifurcation

Posterior cerebral artery

Subtotal

1

1

1

1

1

1

2

Total

56

34

38

128