Uptake of MnCl2 and mangafodipir trisodium in the myocardium: a magnetic resonance imaging study in pigs.
OBJECTIVE
To examine the changes in the longitudinal relaxation times (DeltaR1) induced in pig myocardium and blood following injections of 5, 10, and 15 micromol mangafodipir trisodium (Mn-DPDP) or MnCl2/kg of body weight (b.w.).


METHODS
Twelve pigs were divided into two groups, one group receiving MnCl2 and the other receiving Mn-DPDP. Three consecutive doses of contrast agent (5, 10, and 15 micromol/kg of b.w.) were injected in each animal with a 40-minute time interval between each dose. Measurements of T1 in blood and myocardium were made 5, 15, 25, and 35 minutes after each injection. Additionally, relaxivity measurements in blood samples were performed.


RESULTS
An increase in myocardial R1 was observed for both contrast agents at all concentration levels tested. This increase peaked 5 minutes after injection and then declined. An increase could still be detected 35 minutes after injection. The effect was larger when using MnCl2 than when using Mn-DPDP.


CONCLUSIONS
The dissociation kinetics of Mn2+ from the DPDP ligand limits the relaxation increase of Mn-DPDP relative to that of MnCl2. On the other hand, the toxicity of MnCl2 may exclude it from clinical use.
Eriksson
Rolf
R
MR-Unit, Department of Radiology, Uppsala University Hospital, Uppsala, Sweden. rolf.eriksson@radiol.uu.se
Johansson
Lars
L
Bjerner
Tomas
T
Briley Saebo
Karen
K
Ahlström
Håkan
H
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004492:Edetic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D015636:Magnesium Chloride / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging; D008297:Male; D023421:Models, Animal; D009206:Myocardium / Q000378:metabolism*; D011732:Pyridoxal Phosphate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D013552:Swine
D003287:Contrast Media; D015636:Magnesium Chloride; D011732:Pyridoxal Phosphate; D004492:Edetic Acid; C060076:N,N'-bis(pyridoxal-5-phosphate)ethylenediamine-N,N'-diacetic acid