title: Late-phase contrast-enhanced ultrasound reflects biological features of instability in human carotid atherosclerosis.
abstract: OBJECTIVE
  Development of translational functional imaging modalities for atherosclerosis risk stratification is sought for stroke prediction. Our group has developed late-phase contrast-enhanced ultrasound (LP-CEUS) to quantify microbubble contrast retention within carotid atherosclerosis and shown it to separate asymptomatic plaques from those responsible for recent cerebrovascular events. We hypothesized that microbubbles are retained in areas of plaque inflammation, aiming to examine whether LP-CEUS signal reflects plaque biology.
  
  
  METHODS
  Subjects awaiting carotid endarterectomy (n=31) underwent axial LP-CEUS and diseased intimal segments were symmetrically divided in the long axis. Half-specimens underwent quantitative immunohistochemical analysis for CD68 (macrophages) and CD31 (angiogenesis). Half-specimens were processed for atheroma cell culture and supernatant collected at 24 hours for multianalyte profiling for 34 analytes.
  
  
  RESULTS
  Percentage area immunopositivity was significantly higher in subjects in which normalized plaque late-phase intensity was ≥0 versus <0 (CD68 mean 11.8 versus 6.68, P=0.004; CD31 mean 9.45 versus 4.82, P=0.025). Interleukin-6, matrix metalloproteinase-1, and matrix metalloproteinase-3 were significantly higher by multianalyte profiling when LP-CEUS was ≥0.
  
  
  CONCLUSIONS
  LP-CEUS reflects biological features of inflammation and angiogenesis, key features predisposing to plaque rupture. Further investigation of LP-CEUS as a tissue-specific marker of inflammation for risk stratification of carotid atherosclerosis is warranted.
authors.affiliation: Academic Section of Vascular Surgery, Department of Experimental Medicine, Imperial College London, and Charing Cross Hospital, London W6 8RF, UK.
authors.forename: Joseph
authors.initials: J
authors.lastname: Shalhoub
authors.forename: Claudia
authors.initials: C
authors.lastname: Monaco
authors.forename: David R J
authors.initials: DR
authors.lastname: Owen
authors.forename: Thomas
authors.initials: T
authors.lastname: Gauthier
authors.forename: Ankur
authors.initials: A
authors.lastname: Thapar
authors.forename: Edward L S
authors.initials: EL
authors.lastname: Leen
authors.forename: Alun H
authors.initials: AH
authors.lastname: Davies
mesh_terms: D000368:Aged; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000601:surgery; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000601:surgery; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D045423:Microbubbles; D014463:Ultrasonography