Radiology, Vol 176, 467-472, Copyright © 1990 by Radiological Society of North America
Localization of P-31 MR signal with use of superparamagnetic iron oxide particles
BL Engelstad, DL White, ME Moseley and DD Stark
Department of Radiology, University of California School of Medicine, San Francisco 94143-0628.
Volume localization of magnetic resonance signals was achieved by using the
regional susceptibility differences produced by superparamagnetic iron
oxide particles. In vitro experiments demonstrated a direct linear
relationship between the concentration of particulate iron and
phosphorus-31 chemical shift or line broadening. In vivo experiments
indicated that an intravenous dose of 5-10 mg of iron per kilogram of body
weight suppressed P-31 signal from normal liver in healthy rats. In rats
with hepatic implants of mammary adenocarcinoma, superparamagnetic iron
oxide particles suppressed detectable P-31 or hydrogen-1 signal arising
from healthy liver tissue, but not that from tumor. Signal due to surface
tissues, which affect surface-coil spectra, could be selectively suppressed
with a film-based application of particles to the abdominal wall. Thus,
P-31 spectra from simulated or actual lesions could be selectively detected
after chemically suppressing signals from neighboring or surrounding
tissue.
