MR imaging of nitrosyl-iron complexes: experimental study in rats.
OBJECTIVE
To assess the influence of several nitrosyl-iron complexes on proton nuclear spin relaxation rates to establish a magnetic resonance (MR) imaging technique for nitric oxide.


METHODS
The influence of aqueous phantom solutions of nitrosyl-iron complexes on proton relaxation rates was analyzed for signal enhancement at conventional 1.5-T MR imaging. To induce formation of nitrosyl-iron complexes in a biologic tissue, isolated rat liver was perfused with a saline solution of the NO donor sodium nitroprusside (SNP), and the MR signal intensity was examined thereafter.


RESULTS
All investigated nitrosyl-iron complexes shortened the longitudinal, or T1, and transverse, or T2, relaxation times in a concentration-dependent fashion. Relaxivities were highest with a dinitrosyl-iron complex bound to albumin and with a water-soluble mononitrosyl-iron dithiocarbamate complex. The contrast properties of 240 micromol/L of a paramagnetic nitrosyl-iron complex were sufficient to substantially enhance the signal intensity of SNP-perfused rat livers at hydrogen 1 MR imaging.


CONCLUSIONS
Nitrosyl-iron complexes exhibit a contrast effect at MR imaging that can be exploited for NO imaging in living animals and patients with conventional (1)H MR imaging techniques.
Fichtlscherer
B
B
Institut für Kardiovaskuläre Physiologie, Klinikum der Johann Wolfgang Goethe-Universität, Theodor-Stern-Kai 7, D-60590 Frankfurt, Germany.
Mülsch
A
A
D000818:Animals; D003287:Contrast Media; D004578:Electron Spin Resonance Spectroscopy; D007501:Iron; D008099:Liver / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D009569:Nitric Oxide / Q000032:analysis; D009589:Nitrogen Oxides; D019047:Phantoms, Imaging; D051381:Rats; D011921:Rats, Inbred WKY
D003287:Contrast Media; D009589:Nitrogen Oxides; D009569:Nitric Oxide; C073661:dinitrosyl iron complex; D007501:Iron