Use of a paramagnetic substance, colloidal manganese sulfide, as an NMR contrast material in rats.

Paramagnetic pharmaceuticals ( magnetopharmaceuticals ) that are suitably distributed into specific organ systems or diseased sites might be clinically useful for tissue contrast enhancement in nuclear magnetic resonance images. To determine whether an insoluble magnetopharmaceutical might be useful in such service, we investigated the effect of a colloidal preparation of manganese sulfide ( MnSC ) upon liver and lung spin-lattice relaxation times (T1) in rats following intravenous administration. NMR tissue sample measurements were made at 24 MHz, ahd showed that after MnSC treatment, liver T1 values--and to a lesser extent lung T1 values--were depressed below control values. Liver manganese content (as determined by flame atomic absorption spectrophotometry) increased in proportion to the dose of MnSC , and the reciprocal of the liver T1 values also increased in proportion to the dose of MnSC .