Table 1.
Ultrastructural Grading System.
| Edema | |
| None | 0 |
| Interstitial | 1 |
| Perivascular | 2 |
| Perivascular with vesicles | 3 |
| Massive perivascular and perineuronal | 4 |
| Fragmentation of blood-brain barrier | 5 |
| Neurons | |
| None | 0 |
| Indentation | 1 |
| Margination of chromatin | 2 |
| Apoptosis, necrosis | 3 |
| Astrocytes | |
| None | 0 |
| Swelling | 1 |
| Margination of chromatin | 2 |
| Apoptosis, necrosis | 3 |
| Myelin | |
| Normal | 0 |
| Separation in configuration | 1 |
| Interruption in configuration | 2 |
| Honeycomb appearance | 3 |
| Endothelial BM detachment | |
| Normal | 0 |
| Detached | 1 |
| Maximum points | 15 |
Abbreviation: BM, basement membrane.