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New generation of monomer‐stabilized very small superparamagnetic iron oxide particles (VSOP) as contrast medium for MR angiography: Preclinical results in rats and rabbits
Author(s) -
Taupitz Matthias,
Schnorr Jörg,
Abramjuk Claudia,
Wagner Susanne,
Pilgrimm Herbert,
Hünigen Hanna,
Hamm Bernd
Publication year - 2000
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/1522-2586(200012)12:6<905::aid-jmri14>3.0.co;2-5
Subject(s) - contrast (vision) , contrast medium , superparamagnetism , angiography , radiology , monomer , materials science , medicine , nuclear medicine , biomedical engineering , polymer , optics , physics , composite material , magnetization , quantum mechanics , magnetic field
The purpose of this study was to evalute the signal enhancement characteristics of very small superparamagnetic iron oxide particles (VSOP)‐C63, a new monomer‐coated, iron oxide‐based magnetic resonance (MR) blood pool contrast medium with a very small particle size and optimized physical properties. Equilibrium MR angiography (MRA) of rats (thoracic and abdominal vessels) was performed at 1.5 T with a three‐dimensional gradient‐recalled echo (3D GRE) technique (TR/TE 6.6/2.3 msec, flip angle 25°) before and after (every 3–5 minutes up to 50 minutes) i.v. injection of VSOP‐C63 [dosages: 15, 30, 45, 60, 75, and 90 μmol Fe/kg; diameter: 8 nm; relaxivities at 0.47 T: R1 = 30 l/(mmol • s); R2 = 39 l/(mmol • s)]. First‐pass MRA images (3D‐GRE, TR/TE 4.5/1.7 msec, flip angle 25°) were obtained with 45 μmol Fe/kg VSOP‐C63 in comparison with 0.2 mmol Gd/kg of gadolinium diethylene triamine pentaacetic acid (Gd DTPA; before and every 5 seconds p.i.). MRA (3D GRE, TR/TE 4.5/1.7 msec, flip angle 25°) of coronary vessels in rabbits was performed after i.v. injection of 45 μmol Fe/kg of VSOP‐C63. In rats maximal S/N ratio in thoracic and abdominal arteries directly after i.v. injection of VSOP‐C63 was 25 ± 1, 43 ± 2, 49 ± 4, 57 ± 3, 64 ± 3, and 63 ± 3 for the different dosages. Blood half‐life was dose dependent (15 ± 2, 20 ± 3, 29 ± 6, 37 ± 5, 61 ± 16, and 86 ± 21 minutes). At a dose of 30 μmol Fe/kg even small intrarenal arteries were sharply delineated. First‐pass MRA showed no significant difference in the S/N ratio between Gd‐DTPA (71.5 ± 11.5) and VSOP‐C63 (65.1 ± 18.3). The proximal segments of the coronary arteries in rabbits were clearly depicted at a dose of 45 μmol Fe/kg. The monomer‐coated, iron oxide‐based contrast medium VSOP‐C63 exhibits favorable properties as a blood pool agent for both equilibrium and first‐pass MRA. J. Magn. Reson. Imaging 2000;12:905–911. © 2000 Wiley‐Liss, Inc.