Publications by authors named "Guillaume Radecki"

4 Publications

  • Page 1 of 1

In vivo online magnetic resonance quantification of absolute metabolite concentrations in microdialysate.

Sci Rep 2016 11 4;6:36080. Epub 2016 Nov 4.

ISM, UMR 5255, Université Bordeaux, 33076, Bordeaux, France.

In order to study metabolic processes in animal models of diseases and in patients, microdialysis probes have evolved as powerful tools that are minimally invasive. However, analyses of microdialysate, performed remotely, do not provide real-time monitoring of microdialysate composition. Microdialysate solutions can theoretically be analyzed online inside a preclicinal or clinical MRI scanner using MRS techniques. Due to low NMR sensitivity, acquisitions of real-time NMR spectra on very small solution volumes (μL) with low metabolite concentrations (mM range) represent a major issue. To address this challenge we introduce the approach of combining a microdialysis probe with a custom-built magnetic resonance microprobe that allows for online metabolic analysis (H and C) with high sensitivity under continuous flow conditions. This system is mounted inside an MRI scanner and allows performing simultaneously MRI experiments and rapid MRS metabolic analysis of the microdialysate. The feasibility of this approach is demonstrated by analyzing extracellular brain cancer cells (glioma) in vitro and brain metabolites in an animal model in vivo. We expect that our approach is readily translatable into clinical settings and can be used for a better and precise understanding of diseases linked to metabolic dysfunction.
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http://dx.doi.org/10.1038/srep36080DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5095764PMC
November 2016

DLA based compressed sensing for high resolution MR microscopy of neuronal tissue.

J Magn Reson 2015 Oct 31;259:186-91. Epub 2015 Aug 31.

Neurospin, CEA Saclay, 91191 Gif sur Yvette, France. Electronic address:

In this work we present the implementation of compressed sensing (CS) on a high field preclinical scanner (17.2 T) using an undersampling trajectory based on the diffusion limited aggregation (DLA) random growth model. When applied to a library of images this approach performs better than the traditional undersampling based on the polynomial probability density function. In addition, we show that the method is applicable to imaging live neuronal tissues, allowing significantly shorter acquisition times while maintaining the image quality necessary for identifying the majority of neurons via an automatic cell segmentation algorithm.
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http://dx.doi.org/10.1016/j.jmr.2015.08.012DOI Listing
October 2015

[The functional imaging of individual neurons within complex networks].

Med Sci (Paris) 2015 Jan 6;31(1):15-7. Epub 2015 Feb 6.

NeuroSpin, Commissariat à l'énergie atomique et aux énergies alternatives, 91191 Gif-sur-Yvette, France.

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http://dx.doi.org/10.1051/medsci/20153101004DOI Listing
January 2015

Functional magnetic resonance microscopy at single-cell resolution in Aplysia californica.

Proc Natl Acad Sci U S A 2014 Jun 28;111(23):8667-72. Epub 2014 May 28.

NeuroSpin, Commissariat à l'Energie Atomique et aux Energies Alternatives, 91191 Gif-sur-Yvette, France; and

In this work, we show the feasibility of performing functional MRI studies with single-cell resolution. At ultrahigh magnetic field, manganese-enhanced magnetic resonance microscopy allows the identification of most motor neurons in the buccal network of Aplysia at low, nontoxic Mn(2+) concentrations. We establish that Mn(2+) accumulates intracellularly on injection into the living Aplysia and that its concentration increases when the animals are presented with a sensory stimulus. We also show that we can distinguish between neuronal activities elicited by different types of stimuli. This method opens up a new avenue into probing the functional organization and plasticity of neuronal networks involved in goal-directed behaviors with single-cell resolution.
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http://dx.doi.org/10.1073/pnas.1403739111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4060695PMC
June 2014