Superparamagnetically labelled neutrophils as potential abscess-specific contrast agent for MRI

• Published in: Magnetic resonance imaging Vol. 13; no. 3; pp. 393 - 400
• Main Authors: Krieg, Felix M., Andres, Roger Y., Winterhalter, Kaspar H.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 1995; Elsevier Science
• Subjects: Abscess - diagnosis; Animals; Biological and medical sciences; Cell Aggregation - drug effects; Chemotaxis, Leukocyte - drug effects; Contrast agents; Contrast Media; Contrast-enhanced MRI; Ferrosoferric Oxide; Humans; In Vitro Techniques; Investigative techniques, diagnostic techniques (general aspects); Iron - pharmacology; Magnetic Resonance Imaging; Magnetite; Medical sciences; Miscellaneous. Technology; Models, Structural; Neutrophils - physiology; Oxides - pharmacology; Rabbits; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Superoxides - metabolism; Superparamagnetic iron oxide particles; Superparamagnetically labelled neutrophils; Superparamagnetic iron oxide particles; Contrast agents; Superparamagnetically labelled neutrophils; Magnetite; Contrast-enhanced MRI; Image quality; Abscess; Paramagnetic contrast agent; Neutrophil; Nuclear magnetic resonance imaging; Optimization
• ISSN: 0730-725X; 1873-5894
• DOI: 10.1016/0730-725X(94)00111-F

In order to evaluate the potential of superparamagnetically labelled neutrophils as inflammation-specific contrast agents for magnetic resonance imaging (MRI), various types of magnetite particles were associated with isolated human neutrophils in vitro and subsequent effects on characteristic cellular functions investigated. Exposure to uncoated magnetite caused strong irreversible cell aggregation, whereas uptake of polystyrene-embedded magnetite microcrystals (Estapor ® M 1- 0.70 60 ) occurred with only minor changes in neutrophil adhesion properties, cellular metabolism, and chemotactic behaviour in vitro. As revealed by MR phantom imaging, Estapor ®-labelled neutrophils generated visible contrast above a threshold concentration of 1–2 μg Fe/g in a tissue-equivalent environment. Intravenous administration of labelled neutrophils to rabbits resulted in local magnetite accumulation up to 2.4 μg Fe/g tissue in artificial inflammation sites. Subsequent T 2-weighted imaging of an intramuscular abscess clearly demonstrated the expected hypointense area surrounding the typically bright core of inflammation.