Iron-dextran as a magnetic susceptibility contrast agent: flow-related contrast effects in the T2-weighted spin-echo MRI of normal rat and cat brain.
Iron-dextran (1 mmol Fe/kg) was used as an intravascular, paramagnetic contrast agent in rat and cat brain in conventional spin-echo T2-weighted (TR 2800/TE 100) 1H magnetic resonance imaging. The resulting images displayed differential decreases (30-50%) in intensity whose pattern was similar to that obtained with the superparamagnetic particulate iron oxide AMI-25 (0.18 mmol Fe/kg). Postcontrast images displayed improved anatomic detail, and contrast effects were observed to be greater in cortical and subcortical gray matter than in adjacent white matter. Intravenous injection of acetazolamide after administration of iron-dextran caused a small additional decrease in image intensity. Measurement of whole blood and plasma at 5 min postinjection of either contrast agent revealed significant increases in their volume magnetic susceptibilities. The contrast effect appears to be related to magnetic susceptibility changes brought about by the iron-dextran; it has both blood volume and blood flow components. The static model of magnetic susceptibility effects in brain capillaries is modified to include bolus flow of erythrocytes, providing a mechanism for the observed flow effects.
White
D L
DL
Department of Radiology, University of California, San Francisco 94143.
Aicher
K P
KP
Tzika
A A
AA
Kucharczyk
J
J
Engelstad
B L
BL
Moseley
M E
ME
D000086:Acetazolamide / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000033:anatomy & histology* / Q000098:blood supply; D002196:Capillaries / Q000502:physiology; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003287:Contrast Media; D003911:Dextrans; D004578:Electron Spin Resonance Spectroscopy; D052203:Ferrosoferric Oxide; D005682:Gadolinium; D019786:Gadolinium DTPA; D007089:Image Enhancement / Q000379:methods; D007501:Iron; D007505:Iron-Dextran Complex / Q000097:blood; D008279:Magnetic Resonance Imaging / Q000379:methods; D058185:Magnetite Nanoparticles; D008297:Male; D008536:Meglumine; D009942:Organometallic Compounds; D010087:Oxides; D004369:Pentetic Acid / Q000031:analogs & derivatives; D051381:Rats; D011919:Rats, Inbred Strains; D012212:Rheology
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D009942:Organometallic Compounds; D010087:Oxides; D008536:Meglumine; D004369:Pentetic Acid; D007505:Iron-Dextran Complex; C055865:dysprosium DTPA; D005682:Gadolinium; D007501:Iron; C065507:ferumoxides; D019786:Gadolinium DTPA; D000086:Acetazolamide; D052203:Ferrosoferric Oxide