Abstract
Purpose
Multimodal instrumentation is a new technical approach allowing simultaneous and complementary in vivo recordings of complementary biological parameters. To elucidate further the physiopathological mechanisms in intact small animal models, especially for brain studies, a challenging issue is the actual coupling of magnetic resonance imaging (MRI) techniques with positron emission tomography (PET): it has been shown that running the technology for radioactive imaging in a magnet alters the spatiotemporal performance of both modalities. Thus, we propose an alternative coupling of techniques that uses the β-MicroProbe instead of PET for local measurements of radioactivity coupled with MRI.
Methods
We simultaneously recorded local radioactivity due to [18F]MPPF (a 5-HT1A receptor PET radiotracer) binding in the hippocampus with the β-MicroProbe and carried out anatomical MRI in the same anaesthetised rat.
Results
The comparison of [18F]MPPF kinetics obtained from animals in a magnet with kinetics from a control group outside the magnet allowed us to determine the stability of tracer biokinetic measurements over time in the magnet. We were thus able to show that the β-MicroProbe reliably measures radioactivity in rat brains under an intense magnetic field of 7 Tesla.
Conclusion
The biological validation of a β-MicroProbe/MRI dual system reported here opens up a wide range of future multimodal approaches for functional and pharmacological measurements by the probe combined with various magnetic resonance technologies, including anatomical MRI, functional MRI and MR spectroscopy.
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Acknowledgements
The authors thank Rhône-Alpes Genopole and Fondation Rhône-Alpes Futur funded by the Réseau National des Genopoles.
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Desbrée, A., Rbah, L., Langlois, JB. et al. Simultaneous in vivo magnetic resonance imaging and radioactive measurements with the β-MicroProbe. Eur J Nucl Med Mol Imaging 34, 1868–1872 (2007). https://doi.org/10.1007/s00259-007-0475-5
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DOI: https://doi.org/10.1007/s00259-007-0475-5