title: Compensatory UTE/T2W Imaging of Inflammatory Vascular Wall in Hyperlipidemic Rabbits.
abstract: OBJECTIVE
  To obtain compensatory ultra-short echo time (UTE) imaging and T2-weighted (T2W) imaging of Watanabe heritable hyperlipidemic (WHHL) rabbits following dextran-coated magnetic nanocluster (DMNC) injection for the effective in vivo detection of inflammatory vascular wall.
  
  
  METHODS
  Magnetic nanoparticle was synthesized by thermal decomposition and encapsulated with dextran to prepare DMNC. The contrast enhancement efficiency of DMNC was investigated using UTE (repetition time [TR] = 5.58 and TE = 0.07 ms) and T2W (TR = 4000 and TE = 60 ms) imaging sequences. To confirm the internalization of DMNC into macrophages, DMNC-treated macrophages were visualized by cellular transmission electron microscope (TEM) and magnetic resonance (MR) imaging. WHHL rabbits expressing macrophage-rich plaques were subjected to UTE and T2W imaging before and after intravenous DMNC (120 μmol Fe/kg) treatment. Ex vivo MR imaging of plaques and immunostaining studies were also performed.
  
  
  RESULTS
  Positive and negative contrast enhancement of DMNC solutions with increasing Fe concentrations were observed in UTE and T2W imaging, respectively. The relative signal intensities of the DMNC solution containing 2.9 mM Fe were calculated as 3.53 and 0.99 in UTE and T2W imaging, respectively. DMNC uptake into the macrophage cytoplasm was visualized by electron microscopy. Cellular MR imaging of DMNC-treated macrophages revealed relative signals of 3.00 in UTE imaging and 0.98 in T2W imaging. In vivo MR images revealed significant brightening and darkening of plaque areas in the WHHL rabbit 24 h after DMNC injection in UTE and T2W imaging, respectively. Ex vivo MR imaging results agreed with these in vivo MR imaging results. Histological analysis showed that DMNCs were localized to areas of inflammatory vascular wall.
  
  
  CONCLUSIONS
  Using compensatory UTE and T2W imaging in conjunction with DMNC is an effective approach for the noninvasive in vivo imaging of atherosclerotic plaque.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, Republic of Korea.
authors.forename: Bongjune
authors.initials: B
authors.lastname: Kim
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; YUHS-KRIBB Medical Convergence Research Institute, Seoul, Republic of Korea.
authors.forename: Jaemoon
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; YUHS-KRIBB Medical Convergence Research Institute, Seoul, Republic of Korea.
authors.forename: Young Han
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, Republic of Korea.
authors.forename: Myeong-Hoon
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; Nanomedical National Core Research Center, Yonsei University, Seoul, Republic of Korea.
authors.forename: Dan
authors.initials: D
authors.lastname: Heo
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; Nanomedical National Core Research Center, Yonsei University, Seoul, Republic of Korea.
authors.forename: Eugene
authors.initials: E
authors.lastname: Lee
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; Nanomedical National Core Research Center, Yonsei University, Seoul, Republic of Korea; YUHS-KRIBB Medical Convergence Research Institute, Seoul, Republic of Korea.
authors.forename: Jin-Suck
authors.initials: JS
authors.lastname: Suh
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, Republic of Korea.
authors.forename: Seungjoo
authors.initials: S
authors.lastname: Haam
authors.affiliation: Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Huh
mesh_terms: D000818:Animals; D002460:Cell Line; D003287:Contrast Media / Q000737:chemistry; D008264:Macrophages; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry; D008297:Male; D051379:Mice; D058226:Plaque, Atherosclerotic / Q000175:diagnosis; D011817:Rabbits
chemical_list: D003287:Contrast Media; D058185:Magnetite Nanoparticles