Vascular characteristics of sVAD in medial MI and lateral MI
| Medial MI N=3 | Lateral MI N=43 | Both medial and lateral MI N=1 | P | |
| Bilateral vertebral arteries dissection, N (%) | 0 | 9 (20.93) | 0 | 0.596 |
| V4 segment involvement, N (%) | 3 (100.00) | 34 (79.07) | 1 (100.00) | 0.596 |
| The site of artery dissection, N (%) | 0.532 | |||
| V1 | 0 | 2 (4.65) | 0 | |
| V2 | 2 (66.67) | 10 (23.26) | 0 | |
| V3 | 1 (33.33) | 15 (34.88) | 0 | |
| V4 | 0 | 16 (37.21) | 1 (100.00) | |
| Dissecting aneurysm, N (%) | 0 | 2 (4.65) | 0 | 0.907 |
| Intimal flap, N (%) | 0 | 2 (4.65) | 0 | 0.907 |
| Pearl-and-string sign, N (%) | 1 (33.33) | 6 (13.95) | 0 | 0.604 |
| Double-lumen, N (%) | 1 (33.33) | 4 (9.30) | 0 | 0.401 |
| Tapered steno-occlusion plus evidence of intramural haematoma, N (%) | 1 (33.33) | 29 (67.44) | 1 (100.00) | 0.372 |
MI, medullary infarction; sVAD, spontaneous vertebral artery dissection.