title: Monitoring plaque inflammation in atherosclerotic rabbits with an iron oxide (P904) and (18)F-FDG using a combined PET/MR scanner.
abstract: OBJECTIVE
  The aim of this study was to compare the ability of (18)F-FDG PET and iron contrast-enhanced MRI with a novel USPIO (P904) to assess change in plaque inflammation induced by atorvastatin and dietary change in a rabbit model of atherosclerosis using a combined PET/MR scanner.
  
  
  METHODS
  Atherosclerotic rabbits underwent USPIO-enhanced MRI and (18)F-FDG PET in PET/MR hybrid system at baseline and were then randomly divided into a progression group (high cholesterol diet) and a regression group (chow diet and atorvastatin). Each group was scanned again 6 months after baseline imaging. R2* (i.e. 1/T2*) values were calculated pre/post P904 injection. (18)F-FDG PET data were analyzed by averaging the mean Standard Uptake Value (SUVmean) over the abdominal aorta. The in vivo imaging was then correlated with matched histological sections stained for macrophages.
  
  
  RESULTS
  (18)F-FDG PET showed strong FDG uptake in the abdominal aorta and P904 injection revealed an increase in R2* values in the aortic wall at baseline. At 6 months, SUVmean values measured in the regression group showed a significant decrease from baseline (p = 0.015). In comparison, progression group values remained constant (p = 0.681). R2* values showed a similar decreasing trend in the regression group suggesting less USPIO uptake in the aortic wall. Correlations between SUVmean or Change in R2* value and macrophages density (RAM-11 staining) were good (R(2) = 0.778 and 0.707 respectively).
  
  
  CONCLUSIONS
  This experimental study confirms the possibility to combine two functional imaging modalities to assess changes in the inflammation of atherosclerotic plaques. (18)F-FDG-PET seems to be more sensitive than USPIO P904 to detect early changes in plaque inflammation.
authors.affiliation: Translational and Molecular Imaging Institute, Imaging Science Laboratories, Department of Radiology and Medicine, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA. antoinemillon@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Millon
authors.forename: S D
authors.initials: SD
authors.lastname: Dickson
authors.forename: A
authors.initials: A
authors.lastname: Klink
authors.forename: D
authors.initials: D
authors.lastname: Izquierdo-Garcia
authors.forename: J
authors.initials: J
authors.lastname: Bini
authors.forename: E
authors.initials: E
authors.lastname: Lancelot
authors.forename: S
authors.initials: S
authors.lastname: Ballet
authors.forename: P
authors.initials: P
authors.lastname: Robert
authors.forename: J
authors.initials: J
authors.lastname: Mateo de Castro
authors.forename: C
authors.initials: C
authors.lastname: Corot
authors.forename: Z A
authors.initials: ZA
authors.lastname: Fayad
mesh_terms: D000818:Animals; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology; D001018:Aortic Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D050197:Atherosclerosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D000069059:Atorvastatin; D003287:Contrast Media; D003911:Dextrans; D004195:Disease Models, Animal; D018450:Disease Progression; D019788:Fluorodeoxyglucose F18; D006538:Heptanoic Acids / Q000494:pharmacology; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D007249:Inflammation / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D008279:Magnetic Resonance Imaging; D058185:Magnetite Nanoparticles; D058226:Plaque, Atherosclerotic; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011758:Pyrroles / Q000494:pharmacology; D011817:Rabbits; D011859:Radiography; D019275:Radiopharmaceuticals; D013997:Time Factors
chemical_list: D003287:Contrast Media; D003911:Dextrans; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D058185:Magnetite Nanoparticles; D011758:Pyrroles; D019275:Radiopharmaceuticals; C097921:ferumoxtran-10; D019788:Fluorodeoxyglucose F18; D000069059:Atorvastatin