title: 18F-FDG PET and intravascular ultrasonography (IVUS) images compared with histology of atherosclerotic plaques: 18F-FDG accumulates in foamy macrophages.
abstract: OBJECTIVE
  Intravascular ultrasonography (IVUS) and (18)F-FDG PET have been used to evaluate the efficacy of antiatherosclerosis drugs. These two modalities image different characteristics of atherosclerotic plaques, and a comparison of IVUS and PET images with histology has not been performed. The aim of this study was to align IVUS and PET images using anatomic landmarks in Watanabe heritable hyperlipidaemic (WHHL) rabbits, enabling comparison of their depiction of aortic atherosclerosis. Cellular (18)F-FDG localization was evaluated by (3)H-FDG microautoradiography (micro-ARG).
  
  
  METHODS
  A total of 19 WHHL rabbits (7 months of age) were divided into three groups: baseline (n = 6), 3 months (n = 4), and 6 months (n = 9). PET, IVUS and histological images of the same aortic segments were analysed. Infiltration by foamy macrophages was scored from 0 to IV using haematoxylin and eosin (H&E) and antimacrophage immunohistochemical staining, and compared with (3)H-FDG micro-ARG findings in two additional WHHL rabbits.
  
  
  RESULTS
  IVUS images did not identify foamy macrophage deposition but revealed the area of intimal lesions (r = 0.87). (18)F-FDG PET revealed foamy macrophage distribution in the plaques. The intensity of (18)F-FDG uptake was correlated positively with the degree of foamy macrophage infiltration. Micro-ARG showed identical (3)H-FDG accumulation in the foamy macrophages surrounding the lipid core of the plaques.
  
  
  CONCLUSIONS
  F-FDG PET localized and quantified the degree of infiltration of foamy macrophages in atherosclerotic lesions. IVUS defined the size of lesions. (18)F-FDG PET is a promising imaging technique for evaluating atherosclerosis and for monitoring changes in the composition of atherosclerotic plaques affecting their stability.
authors.affiliation: Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Japan, seigo.ishino@takeda.com.
authors.forename: Seigo
authors.initials: S
authors.lastname: Ishino
authors.forename: Mikako
authors.initials: M
authors.lastname: Ogawa
authors.forename: Ikuo
authors.initials: I
authors.lastname: Mori
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nishimura
authors.forename: Shota
authors.initials: S
authors.lastname: Ikeda
authors.forename: Taku
authors.initials: T
authors.lastname: Sugita
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Oikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Horiguchi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Magata
mesh_terms: D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging / Q000473:pathology; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D005487:Foam Cells / Q000000981:diagnostic imaging*; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D011817:Rabbits; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D018084:Ultrasonography, Interventional
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18