| % Stenosis |
Peak Velocity |
Velocity Ratio |
| Normal/No plaque |
<150 cm/s |
<2 |
| <50% (plaque imaged) |
150-200 cm/s |
1.5:1-2:1 |
| 50-75% |
200-400 cm/s |
2:1-4:1 |
| >75% |
>400 cm/s |
>4:1 |
| Occlusion |
No color saturation or obtainable pulsed wave |
- Waveform characteristics are to be considered.
- Normal-triphasic pattern with three distinct components. Initial forward flow, brief reversal of flow, and a final period of forward flow.
- Biphasic-The final period of forward flow is not evident. This waveform is considered relatively normal.
- Abnormal/Monophasic- A single component of forward flow that is either high amplitude or low amplitude. The upstroke may be dampened.
- Absent-No detectable flow.
- In cases of conflicting velocity and ratio information, the ratios are to be used for quantification.
References:
Crossman DV, Ellison, JE, et al.
Comparison of contrast angiography to arterial mapping with color flow duplex imaging in the lower extremities.
J Vasc Surg 1989; 10:522-32