Note to first time users: for certain categories multiple criteria have to be met in this system. In case of a mismatch caused by conflicting values the calculator will not provide an estimated stenosis range. In this case please consult the detailed ‘Notes’ section below.
Notes
This calculator is based on the latest (November 2021) guidelines of the Australasian Society for Ultrasound in Medicine (ASUM ) but is neither official, nor endorsed by the aforementioned society.
Categories in the ASUM guidelines
- <50% stenosis
- PSV <125 cm/s
- 50-69% stenosis
- PSV >125 cm/s
- OR
- ICA/CCA PSV ratio 2-4
- 70-79% stenosis
- pansystolic spectral broadening with PSV >270 cm/s
- OR
- EDV >110 cm/s
- OR
- ICA/CCA PSV ratio >4
- >80% stenosis
- EDV >140 cm/s
- (PSV >270 cm/s, ICA/CCA PSV ratio >4)
- 95-99% near occlusion
- velocities can be high or low
- always correlate with B-mode and color Doppler, including the string sign
- Occluded
- no flow, terminal thump
Further reading
- ASUM guidelines for duplex Doppler ultrasound of extracranial carotid artery disease (.pdf)
- Radiopaedia article
Last updated: 2022-01-31