Preclinical evaluation of manganese carbonate particles for magnetic resonance imaging of the liver.
OBJECTIVE
We characterized the physical, biological, and imaging properties of a manganese (Mn) carbonate particle suspension, a contrast agent for hepatic magnetic resonance (MR) imaging.


METHODS
Mn carbonate suspensions were produced by controlled precipitation and characterized using light microscopy, transmission electron microscopy, and in vitro relaxivity studies. Efficacy of the agent was studied in normal and tumor-bearing rats using T1-weighted MR imaging.


RESULTS
Following intravenous injection of Mn carbonate particles at doses ranging from 10 to 100 mumol Mn/kg, peak hepatic contrast enhancement of approximately 35% occurred from about 125 min until the termination of the MR imaging studies that varied from 125 to 305 min. Lesion conspicuity was increased because of relative intensity differences between normal liver and tumor. Data also showed that Mn carbonate particles dissolved on delivery to the liver, allowing Mn to interact with intrahepatic macromolecular complexes to provide positive contrast enhancement.


CONCLUSIONS
Mn carbonate particles produce significant and sustained hepatic enhancement and should improve detection of small or isointense liver lesions.
Wisner
E R
ER
Department of Radiology, School of Medicine, University of California, Davis, USA.
Merisko-Liversidge
E
E
Kellar
K
K
Katzberg
R W
RW
Karpinski
P H
PH
Amparo
E G
EG
Drake
C
C
Griffey
S M
SM
Brock
J M
JM
D000704:Analysis of Variance; D000818:Animals; D002254:Carbonates / Q000493:pharmacokinetics / Q000633:toxicity; D003287:Contrast Media / Q000493:pharmacokinetics / Q000633:toxicity; D008099:Liver / Q000473:pathology*; D008114:Liver Neoplasms, Experimental / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008345:Manganese / Q000493:pharmacokinetics; D020149:Manganese Poisoning; D008854:Microscopy, Electron; D009368:Neoplasm Transplantation; D010316:Particle Size; D051381:Rats; D014018:Tissue Distribution
D002254:Carbonates; D003287:Contrast Media; D008345:Manganese; C045327:manganese carbonate