2. DUS criteria for internal carotid stenosis.
| Consensus panel based on Grant 2003 | ||||
| Degree of stenosis (%) | Primary parameters | Additional parameters | ||
| ICA PSV (cm/sec) | Plaque estimate (%)* | ICA/CCA PSV ratio | ICA EDV (cm/sec) | |
| Normal | < 125 | None | < 2.0 | < 40 |
| < 50% | < 125 | < 50 | < 2.0 | < 40 |
| 50% to 69% | 125 to 230 | ≥ 50 | 2.0 to 4.0 | 40 to 100 |
| ≥ 70% but less than near occlusion | > 230 | ≥ 50 | > 4.0 | > 100 |
| Near occlusion | High, low or undetectable | Visible | Variable | Variable |
| Total occlusion | Undetectable | Visible, no detectable lumen | Not applicable | Not applicable |
| *Plaque estimate (diameter reduction) based on DUS B‐mode and on additional colour mode ultrasound. | ||||
CCA: common carotid artery DUS: duplex ultrasound EDV: end diastolic velocity ICA: internal carotid artery PSV: peak systolic velocity