title: Extremely Small Pseudoparamagnetic Iron Oxide Nanoparticle as a Novel Blood Pool T1 Magnetic Resonance Contrast Agent for 3 T Whole-Heart Coronary Angiography in Canines: Comparison With Gadoterate Meglumine.
abstract: The aim of this study was to evaluate an extremely small pseudoparamagnetic iron oxide nanoparticle (ESPIO), KEG3, as a potential blood pool agent in 3 T coronary magnetic resonance angiography (MRA) in canine models and compare its efficacy to that of a gadolinium-based contrast agent.
  
  
  
  Nine mongrel dogs were subjected to whole-heart coronary MRA in 2 separate sessions at 7-day intervals with a 3 T scanner using the FLASH sequence with either gadoterate meglumine (Gd-DOTA) or the ESPIO (KEG3). Coronary MRA was performed twice at each MR examination: the first scan during the administration of the contrast agent and the subsequent second scan at 15 minutes after contrast injection. Objective measurements of the Gd-DOTA and ESPIO images, including the signal-to-noise ratios (SNRs) for the coronary arteries and cardiac veins, contrast-to-noise ratios (CNRs) between the vessels and fat (CNRfat) and the vessels and the myocardium (CNRmyocardium), and subjective image quality scores on a 4-point scale were evaluated and compared.
  
  
  
  The mean SNRs and CNRs of all vascular regions in the ESPIO images were similar to those of the corresponding regions in the Gd-DOTA images in the first scan (98.1 ± 32.5 vs 79.1 ± 38.4 for SNR of coronary arteries, P = 0.3; 74.2 ± 30.1 vs 61.4 ± 38.5 for CNR, P = 0.7) and more than 2 times higher than the latter in the second scan (95.2 ± 31.3 vs 32.1 ± 8.1 for SNR of coronary arteries, P = 0.008; 76.1 ± 35.8 vs 17.6 ± 19.2 for CNR, P 0.008). Similarly, the mean values of the subjective measurements of the ESPIO images were similar to those of the Gd-DOTA images (3.9 ± 0.3 vs 3.3 ± 0.8 for coronary arteries, P = 0.1) in the first scan and significantly better than the latter in the second scan (3.9 ± 0.2 vs 2.1 ± 0.6 for coronary arteries, P = 0.007).
  
  
  
  The experimental blood pool agent KEG3 offers equivalent image quality for whole-heart coronary MRA at 3 T upon contrast administration and persistent better quality in the subsequent scans, compared with a traditional extracellular gadolinium-based contrast agent.
authors.affiliation: From the *Department of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital; †Department of Radiology, Seoul National University Boramae Hospital; ‡Department of Nuclear Medicine, Seoul National University College of Medicine; §Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul; and ∥Research and Development Center, Hanwha Chemical Corp, Daejeon, Yuseong-gu, South Korea.
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Park
authors.forename: Whal
authors.initials: W
authors.lastname: Lee
authors.forename: Young Ho
authors.initials: YH
authors.lastname: So
authors.forename: Yun-Sang
authors.initials: YS
authors.lastname: Lee
authors.forename: Bong-Sik
authors.initials: BS
authors.lastname: Jeon
authors.forename: Kyu Sung
authors.initials: KS
authors.lastname: Choi
authors.forename: Eung-Gyu
authors.initials: EG
authors.lastname: Kim
authors.forename: Wan-Jae
authors.initials: WJ
authors.lastname: Myeong
mesh_terms: D000818:Animals; D003287:Contrast Media; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004285:Dogs; D005290:Ferric Compounds; D007089:Image Enhancement / Q000379:methods*; D007275:Injections, Intravenous; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008536:Meglumine; D023421:Models, Animal; D053758:Nanoparticles; D009942:Organometallic Compounds; D059629:Signal-To-Noise Ratio
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D009942:Organometallic Compounds; C000499:ferric oxide; D008536:Meglumine; C072417:gadoterate meglumine