Abstract: The invention relates to compositions that comprise (1) lipophilic cationic organometallic complexes, particularly hexakis(2-methoxyisobutylisonitrile)technetium(I) complex, and (2) an agent that decreases the intramembrane potential of a living cell. Agents which decrease the intramembrane potential of a living cell include the lipophilic anions, especially tetraphenylborate anion. The invention also relates to methods in which the compositions are administered in vivo and in vitro when it is desirable to obtain enhanced cellular accumulation of lipophilic cationic organometallic complexes. The compositions and methods are useful for diagnosis and treatment, pSTATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENTPart of the work performed during development of this invention utilized U.S. Government funds. The U.S. Government has certain rights in this invention.

Abstract: Novel magnetic resonance imaging agents methods utilize complexes of paramagnetic ions with alkoxyalkylamide deriviatives of diethylenetriaminepentaacetic acid ("DTPA") or ethylenediaminetetyraacetic acid ("EDTA"). These novel imaging agents are characterized by excellent NMR image-contrasting properties and by high solubilities in physiological solutions.The complexes are represented by the following formula: ##STR1## wherein A is --CH.sub.2 CH.sub.2 -- or ##STR2## and M.sup.+Z is a paramagnetic ion of an element with an atomic number of 21-29, 42-44 or 58-70, and a valence number, Z, of 2 or 3; R.sup.1 is --O.sup.- or R.sup.3 --N--R.sup.2, R.sup.2 is --(CH.sub.2 CH.sub.2 O).sub.n --R.sup.4, n is 1-10, R.sup.4 is alkyl or aryl, R.sup.3 is H, R.sup.2, alkyl, hydroxy, alkoxy, cycloalkyl or aryl, wherein Z of the R.sup.1 groups are --O.sup.- and the remainder of the R.sup.1 groups are R.sup.2 -N--R.sup.3 groups.