title: Clinical and histological significance of gadolinium enhancement in carotid atherosclerotic plaque.
abstract: OBJECTIVE
  Although the ability of MRI to investigate carotid plaque composition is well established, the mechanism and the significance of plaque gadolinium (Gd) enhancement remain unknown. We evaluated clinical and histological significance of Gd enhancement of carotid plaque in patients undergoing endarterectomy for carotid stenosis.
  
  
  METHODS
  Sixty-nine patients scheduled for a carotid endarterectomy prospectively underwent a 3-T MRI. Carotid plaque enhancement was assessed on T1-weighted images performed before and 5 minutes after Gd injection. Enhancement was recorded according to its localization. Histological analysis was performed of the entire plaque and of the area with matched contrast enhancement on MR images.
  
  
  RESULTS
  Gd enhancement was observed in 59% patients. Three types of carotid plaques were identified depending on enhancement location (shoulder region, shoulder and fibrous cap, and central in the plaque). Fibrous cap rupture, intraplaque hemorrhage, and plaque Gd enhancement was significantly more frequent in symptomatic than in asymptomatic patients (P=0.043, P<0.0001, and P=0.034, respectively). After histological analysis, Gd enhancement was significantly associated with vulnerable plaque (American Heart Association VI, P=0.006), neovascularization (P<0.0001), macrophages (P=0.030), and loose fibrosis (P<0.0001). Prevalence of neovessels, macrophages, and loose fibrosis in the area of Gd enhancement was 97%, 87%, and 80%, respectively, and was different depending on the enhancement location in the plaque. Fibrous cap status and composition were different depending on the type of plaque.
  
  
  CONCLUSIONS
  Gd enhancement of carotid plaque is associated with vulnerable plaque phenotypes and related to an inflammatory process.
authors.affiliation: Department of Vascular Surgery, University Hospital of Lyon, Lyon University, Lyon, France. antoinemillon@hotmail.com
authors.forename: Antoine
authors.initials: A
authors.lastname: Millon
authors.forename: Loic
authors.initials: L
authors.lastname: Boussel
authors.forename: Marie
authors.initials: M
authors.lastname: Brevet
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mathevet
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Canet-Soulas
authors.forename: Cyril
authors.initials: C
authors.lastname: Mory
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Scoazec
authors.forename: Philippe
authors.initials: P
authors.lastname: Douek
mesh_terms: D016893:Carotid Stenosis / Q000473:pathology* / Q000601:surgery; D016894:Endarterectomy, Carotid; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted; D002537:Intracranial Arteriosclerosis / Q000473:pathology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058226:Plaque, Atherosclerotic / Q000473:pathology / Q000601:surgery; D012680:Sensitivity and Specificity
chemical_list: D005682:Gadolinium