Relaxation enhancement using liposomes carrying paramagnetic species

• Published in: Magnetic resonance imaging Vol. 2; no. 2; pp. 107 - 112
• Main Authors: Caride, V.J., Sostman, H.D., Winchell, R.J., Gore, J.C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 1984
• Subjects: Animals; Female; Injections, Intravenous; Liposomes; Liposomes - administration & dosage; Magnetic Resonance Spectroscopy - methods; Mice; Paramagnetic contrast agents; Pentetic Acid - metabolism; Relaxation enhancement; Tissue Distribution; Paramagnetic contrast agents; Liposomes; Relaxation enhancement
• ISSN: 0730-725X; 1873-5894
• DOI: 10.1016/0730-725X(84)90064-X

Studies were performed to investigate the effects upon the relaxation times of mouse organs of intravenously administered Mn-DTPA entrapped in multilamellar liposomes, Mn-DTPA, 0.9% NaCl entrapped in liposomes, 0.9% NaCl. Manganese concentrations in injectates and tissues were assessed with 54Mn and atomic absorption. T 1 and T 2 of freshly excised tissues were measured in an NMR spectrometer at 20 MHz and 37%C with IR and CPMG sequences. Entrapment of Mn-DTPA in liposomes increased 54Mn accumulation in liver by 207% and in spleen 1208% and reduced 54Mn in heart by 20% and in kidney by 24% relative to free Mn-DTPA. Statistically significant increases in relaxation rates were produced. However, the increase in relaxation rate per unit concentration of Mn in tissue is reduced by 31% in liver and 62% in spleen when Mn is delivered inside liposomes. These observations have implications for the design of NMR contrast agents.