St. Mary’s Ratio | ICA Stenosis (%) |
<8 | <50 |
8 - 10 | 50 - 59 |
11 - 13 | 60 - 69 |
14 - 21 | 70 - 79 |
22 - 29 | 80 - 89 |
>30 | >90 but less than near occlusion |
Variable | Near occlusion |