Magnetic resonance imaging with superparamagnetic iron oxide particles to evaluate hepatic macrophage-monocytic phagocytosis after arterial devascularization in minipigs.
OBJECTIVE
We examined the effects of arterial ischemia on the phagocytic activity of the hepatic macrophage-monocytic phagocytic system (MMPS).


METHODS
Six minipigs were studied before and 24 hr after complete arterial devascularization of the liver. Magnetic resonance (MR) imaging was performed at 1.5 T using superparamagnetic iron oxide (SPIO) particles (18 mumol Fe/kg body weight) as an MMPS-specific contrast agent. Hepatobiliary scintigraphy, measurements of serum liver enzymes, and histology also were obtained.


RESULTS
On MR imaging, the postcontrast-to-precontrast ratios of the arterially devascularized livers were significantly higher than the corresponding baseline values (p < .01). The greatest difference (52%) between the baseline and the postoperative values was observed on gradient-echo (GE) images. Scintigraphy, laboratory analyses, and histology results indicate that the MR imaging findings were probably predominantly attributable to a reduction in phagocytic activity of the hepatic MMPS.


CONCLUSIONS
SPIO particles have already proved useful for improving detection of liver neoplasms on MR imaging, but they also may provide a novel way of evaluating the function of the hepatic MMPS in liver diseases.
Terrier
F
F
Department of Radiology, University of Geneva, Switzerland.
Tourniaire
J
J
Bélenger
J
J
Slosman
D
D
Rubbia
L
L
Grossholz
M
M
Mentha
G
G
Hiltbrand
E
E
Mermillod
B
B
D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D052203:Ferrosoferric Oxide; D007275:Injections, Intravenous; D007501:Iron / Q000008:administration & dosage; D007511:Ischemia / Q000378:metabolism / Q000503:physiopathology*; D008099:Liver / Q000098:blood supply* / Q000201:enzymology / Q000473:pathology; D008264:Macrophages / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D009000:Monocytes / Q000502:physiology*; D010087:Oxides / Q000008:administration & dosage; D010587:Phagocytosis / Q000502:physiology*; D013552:Swine; D013556:Swine, Miniature; D000637:Transaminases / Q000097:blood
D003287:Contrast Media; D010087:Oxides; D007501:Iron; D000637:Transaminases; D052203:Ferrosoferric Oxide