Distribution of the offending vessels in relation to the vertebrobasilar configuration
| Offending vessel | Type of vertebrobasilar anatomy | Total | |||
|---|---|---|---|---|---|
| Type I (%) | Type II (%) | Type III (%) | |||
| AICA | 6 (18) | 5 (100) | 25 (81) | 36 (52.1%) | |
| PICA | 24 (73) | 0 | 6 (19) | 30 (43.5%) | |
| VA | 3 (9) | 0 | 0 | 3 (4.4%) | |
| Total | 33 | 5 | 31 | 69 | |
AICA=anterior inferior cerebellar artery; PICA=posterior inferior cerebellar artery; VA=vertebral artery. Types I and III are significantly different (p<0.01, two way ANOVA).