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Magnetic resonance imaging with superparamagnetic iron oxide particles to evaluate hepatic macrophage-monocytic
F Terrier1, J Tourniaire, J Bélenger
1Department of Radiology, University of Geneva, Switzerland.
Rationale And Objectives:
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.
Conclusion:
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.
Insights
Arterial ischemia significantly reduces the phagocytic activity of the liver's macrophage-monocytic phagocytic system (MMPS). This functional decline in hepatic MMPS was detected using superparamagnetic iron oxide (SPIO) particles on MRI.
Area of Science:
- Hepatology
- Radiology
- Immunology
Background:
- The hepatic macrophage-monocytic phagocytic system (MMPS) plays a crucial role in liver function.
- Assessing MMPS phagocytic activity is vital for diagnosing and managing liver diseases.
Purpose of the Study:
- To investigate the impact of arterial ischemia on the phagocytic capacity of the hepatic MMPS.
- To evaluate the utility of superparamagnetic iron oxide (SPIO) particles and MRI in assessing these functional changes.
Main Methods:
- Six minipigs underwent liver arterial devascularization.
- Magnetic resonance (MR) imaging with SPIO contrast agents was performed pre- and post-procedure.
- Hepatobiliary scintigraphy, serum liver enzymes, and histology were also utilized.
Main Results:
- MR imaging showed significantly increased postcontrast-to-precontrast ratios in devascularized livers compared to baseline (p < .01).
- Gradient-echo imaging revealed the most substantial difference (52%) between baseline and postoperative values.
- Findings suggest a reduction in hepatic MMPS phagocytic activity following arterial ischemia.
Conclusions:
- MR imaging with SPIO particles can detect functional changes in the hepatic MMPS caused by arterial ischemia.
- SPIO-enhanced MRI offers a novel approach for evaluating MMPS function in liver disease.
- This method complements existing techniques for liver disease assessment.