title: Identification of vascularised carotid plaques using a standardised and reproducible technique to measure ultrasound contrast uptake.
abstract: OBJECTIVE
  Contrast-enhanced ultrasonography (CEUS) has been used to assess the vascularisation of carotid plaques. Our aim was to develop and validate a standardised semi-automated method for CEUS examination of plaques, and test if the technique could be used to identify vulnerable plaques.
  
  
  METHODS
  Study participants were a mixed population of symptomatic and asymptomatic subjects, selected if they had a plaque with height >2.5 mm and <10% acoustic shadowing. Participants received a bolus of ultrasound contrast agent and a 90-s cine-loop was captured. A Contrast Quantification Program (CQP) was developed and trained to identify extent of contrast uptake after motion correction and application of a noise reduction algorithm. The technique was validated by comparing CQP values with visual assessment of contrast uptake. CQP values were also compared with plaque echogenicity and history of clinical events.
  
  
  RESULTS
  CQP values correlated with a visual, 5-scale classification of contrast uptake by two blinded, experienced sonographers. Repeated contrast injections showed high reproducibility. Participants with a history of ipsilateral stroke/TIA had significantly higher CQP values than asymptomatic participants.
  
  
  CONCLUSIONS
  We present a reproducible, semi-automatic method to identify vascularisation of carotid plaques, which could be used in prospective studies to determine the clinical value of plaque vascularisation.
authors.affiliation: Department of Molecular and Clinical Medicine, Clinical Physiology, Institute of Medicine, Sahlgrenska University Hospital, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden. ola.hjelmgren@wlab.gu.se
authors.forename: O
authors.initials: O
authors.lastname: Hjelmgren
authors.forename: P
authors.initials: P
authors.lastname: Holdfeldt
authors.forename: L
authors.initials: L
authors.lastname: Johansson
authors.forename: B
authors.initials: B
authors.lastname: Fagerberg
authors.forename: U
authors.initials: U
authors.lastname: Prahl
authors.forename: C
authors.initials: C
authors.lastname: Schmidt
authors.forename: G M L
authors.initials: GM
authors.lastname: Bergström
mesh_terms: D000368:Aged; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014463:Ultrasonography
chemical_list: D003287:Contrast Media