title: Carotid stenosis measurement on colour Doppler ultrasound: agreement of ECST, NASCET and CCA methods applied to ultrasound with intra-arterial angiographic stenosis measurement.
abstract: OBJECTIVE
  Carotid stenosis is usually determined on Doppler ultrasound from velocity readings. We wondered if angiography-style stenosis measurements applied to ultrasound images improved accuracy over velocity readings alone, and if so, which measure correlated best with angiography.
  
  
  METHODS
  We studied prospectively patients undergoing colour Doppler ultrasound (CDU) for TIA or minor stroke. Those with 50%+ symptomatic internal carotid artery (ICA) stenosis had intra-arterial angiography (IAA). We measured peak systolic ICA velocity, and from the ultrasound image, the minimal residual lumen, the original lumen (ECST), ICA diameter distal (NASCET) and CCA diameter proximal (CCA method) to the stenosis. The IAAs were measured by ECST, NASCET and CCA methods also, blind to CDU.
  
  
  RESULTS
  Amongst 164 patients (328 arteries), on CDU the ECST, NASCET and CCA stenosis measures were similarly related to each other (ECST = 0.54 NASCET + 46) as on IAA (ECST = 0.6 NASCET + 40). Agreement between CDU- and IAA-measured stenosis was similar for ECST (r = 0.51), and CCA (r = 0.48) methods, and slightly worse for NASCET (r = 0.41). Adding IAA-style stenosis to the peak systolic ICA velocity did not improve agreement with IAA over peak systolic velocity alone.
  
  
  CONCLUSIONS
  Angiography-style stenosis measures have similar inter-relationships when applied to CDU, but do not improve accuracy of ultrasound over peak systolic ICA velocity alone.
authors.affiliation: Division of Clinical Neurosciences, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK. jmw@skull.dcn.ed.ac.uk
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Wardlaw
authors.forename: Steff
authors.initials: S
authors.lastname: Lewis
mesh_terms: D000792:Angiography / Q000379:methods / Q000706:statistics & numerical data; D001783:Blood Flow Velocity / Q000502:physiology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging; D011446:Prospective Studies; D012171:Retinal Vessels / Q000000981:diagnostic imaging; D016037:Single-Blind Method; D020521:Stroke / Q000000981:diagnostic imaging; D013599:Systole / Q000502:physiology; D018615:Ultrasonography, Doppler, Color / Q000706:statistics & numerical data