Mn-TPPS4; a potential MRI contrast agent for localizing the normal aortic wall in rabbits

The localizing potential of the Mn (III) complex of tetrakis (4-sulfonatophenyl) porphyrin (Mn-TPPS4) for the normal aortic wall was investigated in nine male New Zealand White rabbits by means of 2.0 T magnetic resonance imaging system. Fortyeight hours after intravenous administration of 0.25-0.50 mmol/kg body weight (b.w.) of Mn-TPPS4, the selective contrast enhancing effects in the normal aortic wall were observed using ECG-gated T1 weighted sequence. An intense brownish internal surface was also observed in the post-mortem aorta. These preliminary results indicate that Mn-TPPS4 might be a suitable MRI contrast agent for the localization of the normal aorta. Acute cardio-toxic effects were observed in one animal after 0.25 mmol/kg b.w. of Mn-TPPS4.