First Multimodal Embolization Particles Visible on X-ray/Computed Tomography and Magnetic Resonance Imaging

OBJECTIVES:Embolization therapy is gaining importance in the treatment of malignant lesions, and even more in benign lesions. Current embolization materials are not visible in imaging modalities. However, it is assumed that directly visible embolization material may provide several advantages over c...

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Veröffentlicht in:Investigative radiology 2011-03, Vol.46 (3), p.178-186
Hauptverfasser: Bartling, Soenke H, Budjan, Johannes, Aviv, Hagit, Haneder, Stefan, Kraenzlin, Bettina, Michaely, Henrik, Margel, Shlomo, Diehl, Steffen, Semmler, Wolfhard, Gretz, Norbert, Schönberg, Stefan O, Sadick, Maliha
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Sprache:eng
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Zusammenfassung:OBJECTIVES:Embolization therapy is gaining importance in the treatment of malignant lesions, and even more in benign lesions. Current embolization materials are not visible in imaging modalities. However, it is assumed that directly visible embolization material may provide several advantages over current embolization agents, ranging from particle shunt and reflux prevention to improved therapy control and follow-up assessment. X-ray- as well as magnetic resonance imaging (MRI)-visible embolization materials have been demonstrated in experiments. In this study, we present an embolization material with the property of being visible in more than one imaging modality, namely MRI and x-ray/computed tomography (CT). Characterization and testing of the substance in animal models was performed. MATERIALS AND METHODS:To reduce the chance of adverse reactions and to facilitate clinical approval, materials have been applied that are similar to those that are approved and being used on a routine basis in diagnostic imaging. Therefore, x-ray-visible Iodine was combined with MRI-visible Iron (Fe3O4) in a macroparticle (diameter, 40–200 μm). Its core, consisting of a copolymerized monomer MAOETIB (2-methacryloyloxyethyl [2,3,5-triiodobenzoate]), was coated with ultra-small paramagnetic iron oxide nanoparticles (150 nm). After in vitro testing, including signal to noise measurements in CT and MRI (n = 5), its ability to embolize tissue was tested in an established tumor embolization model in rabbits (n = 6). Digital subtraction angiography (DSA) (Integris, Philips), CT (Definition, Siemens Healthcare Section, Forchheim, Germany), and MRI (3 Tesla Magnetom Tim Trio MRI, Siemens Healthcare Section, Forchheim, Germany) were performed before, during, and after embolization. Imaging signal changes that could be attributed to embolization particles were assessed by visual inspection and rated on an ordinal scale by 3 radiologists, from 1 to 3. Histologic analysis of organs was performed. RESULTS:Particles provided a sufficient image contrast on DSA, CT (signal to noise [SNR], 13 ± 2.5), and MRI (SNR, 35 ± 1) in in vitro scans. Successful embolization of renal tissue was confirmed by catheter angiography, revealing at least partial perfusion stop in all kidneys. Signal changes that were attributed to particles residing within the kidney were found in all cases in all the 3 imaging modalities. Localization distribution of particles corresponded well in all imaging modalities. Dy
ISSN:0020-9996
1536-0210
DOI:10.1097/RLI.0b013e318205af53