title: Identifying inflamed carotid plaques using in vivo USPIO-enhanced MR imaging to label plaque macrophages.
abstract: BACKGROUND
  Inflammation within atherosclerotic lesions contributes to plaque instability and vulnerability to rupture. We set out to evaluate the use of a macrophage labeling agent to identify carotid plaque inflammation by in vivo magnetic resonance imaging (MRI).
  
  
  RESULTS
  Thirty patients with symptomatic severe carotid stenosis scheduled for carotid endarterectomy underwent multi-sequence MRI of the carotid bifurcation before and after injection of ultrasmall superparamagnetic particles of iron oxide (USPIOs). USPIO particles accumulated in macrophages in 24 of 30 plaques (80%). Areas of signal intensity reduction, corresponding to USPIO/macrophage-positive histological sections, were visualized in 24 of 27 (89%) patients, with an average reduction in signal intensity induced by the USPIO particles of 24% (range, 3.1% to 60.8%).
  
  
  CONCLUSIONS
  USPIO-enhanced MRI can identify plaque inflammation in vivo by accumulation of USPIO within macrophages in carotid plaques.
authors.affiliation: University Department of Radiology, Addenbrooke's Hospital, Cambridge, UK. rt256@radiol.cam.ac.uk
authors.forename: Rikin A
authors.initials: RA
authors.lastname: Trivedi
authors.forename: Chinthake
authors.initials: C
authors.lastname: Mallawarachi
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: U-King-Im
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Graves
authors.forename: Jo
authors.initials: J
authors.lastname: Horsley
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Goddard
authors.forename: Andrew
authors.initials: A
authors.lastname: Brown
authors.forename: Liqun
authors.initials: L
authors.lastname: Wang
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kirkpatrick
authors.forename: John
authors.initials: J
authors.lastname: Brown
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
mesh_terms: D016893:Carotid Stenosis / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D004396:Coloring Agents / Q000493:pharmacokinetics; D003287:Contrast Media; D003911:Dextrans; D052203:Ferrosoferric Oxide; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007249:Inflammation / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D007501:Iron / Q000493:pharmacokinetics; D008264:Macrophages / Q000378:metabolism / Q000473:pathology; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D010087:Oxides / Q000493:pharmacokinetics; D013194:Staining and Labeling; D014018:Tissue Distribution
chemical_list: D004396:Coloring Agents; D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; C097921:ferumoxtran-10; D007501:Iron; D052203:Ferrosoferric Oxide