J. Grimm et al., Characterization of ultrasmall, paramagnetic magnetite particles as superparamagnetic contrast agents in MRI, INV RADIOL, 35(9), 2000, pp. 553-556
Citations number
21
Categorie Soggetti
Radiology ,Nuclear Medicine & Imaging","Medical Research Diagnosis & Treatment
RATIONALE AND OBJECTIVES, Very small dextran-coated magnetite particles wer
e developed. These particles can be used either as immunospecific contrast
agents for MRI by coupling to antibodies or as an interstitial contrast age
nt.
METHODS. The particles were synthesized from iron chloride/dextran solution
s. Size was evaluated by electron microscopy and photon correlation spectro
scopy. The iron concentration was determined by x-ray spectroscopy. T1 and
T2 values as well as relaxivities R1 and R2 were evaluated with a clinical
MR scanner at 1.5 T, Biocompatibility assays were performed with the cell l
ine U937 in methylcellulose cultures.
RESULTS, Superparamagnetic, dextran-coated magnetite particles with a hydro
dynamic diameter of 10 nm were developed. The iron core size was 7 nm; R1,
7 L/mmol.s; and R2, 19 L/mmol.s. These particles are smaller than those cur
rently available commercially and therefore show a smaller R1 to R2 ratio.
Biocompatibility tests have shown no toxic side effects so far.
CONCLUSIONS.. Ultrasmall magnetite particles with a dextran coating were de
veloped; the physical properties of these particles evaluated in vitro are
described in this study.