Table II.
Classification and scoring based on the MRA findings (5).
| A, Scoring for each artery | |
|---|---|
| Score | MRA findings |
| Internal carotid artery | |
| 0 | Normal |
| 1 | Stenosis of C1 |
| 2 | Discontinuity of the C1 signal |
| 3 | Invisible |
| Middle cerebral artery | |
| 0 | Normal |
| 1 | Stenosis of M1 |
| 2 | Discontinuity of the M1 signal |
| 3 | Invisible |
| Anterior cerebral artery | |
| 0 | Normal A2 and blood vessels distal to A2 |
| 1 | Signal decrease A2 and its distal blood vessels |
| 2 | Invisible |
| Posterior cerebral artery | |
| 0 | Normal P2 and blood vessels distal to P2 |
| 1 | Signal decrease P2 and its distal blood vessels |
| 2 | Invisible |
| B, Total score calculated individually for the right and left side | |
| MRA total score | MRA stage |
| 0–1 | 1 |
| 2–4 | 2 |
| 5–7 | 3 |
| 8–10 | 4 |
MRA, magnetic resonance angiography.