The importance of Doppler angle of insonation on differentiation between 50-69% and 70-99% carotid artery stenosis

K. Logason*, T. Bärlin, M. L. Jonsson, A. Boström, H. G. Hårdemark, S. Karacagil

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


Aim: To investigate the importance of Doppler angle differentiating between 50-69% and ≥ 70% internal carotid artery (ICA) stenosis. Material and methods: fifty-one patients with a previous diagnosis of 50-69% ICA stenosis (n=53) were re-evaluated by duplex scanning. Spectral Doppler velocity waveforms were obtained from common carotid (CCA), ICA and external (ECA) carotid arteries with the same Doppler angle of insonation as used at the initial duplex scanning, followed by repeated measurements with a fixed 60° angle of insonation. Results: The peak systolic velocity (PSV) in the ICA was 181 ± 55 cm/s (mean ± SD) at the second duplex scanning when the same angle of insonation (mean 46° ± 9) was used as during the initial investigation. When the examination was done with a 60° angle of insonation, PSV ICA was 261 ± 96 cm/s (mean ± SD). In fifteen arteries the estimated degree of ICA stenosis changed from 50-69% to 70-99% due to the application of a fixed Doppler angle of insonation at 60°. Conclusion: The Doppler angle of insonation has a significant effect on spectral Doppler velocity measurements. It is crucial that duplex criteria are standardised with a fixed angle of insonation and that this angle is consistently used during velocity estimations.

Original languageEnglish
Pages (from-to)311-313
Number of pages3
JournalEuropean Journal of Vascular and Endovascular Surgery
Issue number4
Publication statusPublished - 2001

Bibliographical note

Funding Information:
Funding for this study was received from the Swedish Medical Research Council, grant no. 00759, Swedish Heart and Lung Foundation.

Other keywords

  • Angle of insonation
  • Carotid artery
  • Doppler


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