Table 1 Halo Score Grading
| Halo Grading | Common superficial TA halo thickness (mm) | Parietal TA halo thickness (mm) | Frontal TA halo thickness (mm) | Axillary artery halo thickness (mm) |
|---|---|---|---|---|
| Grade 0 | 0.3 or less | 0.2 or less | 0.1 or less | 0.5 or less |
| Grade 1 | 0.4 | 0.3 | 0.2 | 0.6 |
| Grade 2 | 0.5 | 0.4 | 0.3 | 0.7–0.8 |
| Grade 3 | 0.6–0.7 | 0.5* | 0.4 | 0.9–1.5 |
| Grade 4 | 0.8 or more | 0.6 or more | 0.5 or more | 1.6 or more |