title: Quantification of iron in the non-human primate brain with diffusion-weighted magnetic resonance imaging.
abstract: Pathological iron deposits in the brain, especially within basal ganglia, are linked to severe neurodegenerative disorders like Parkinson's disease. As iron induces local changes in magnetic susceptibility, its presence can be visualized with magnetic resonance imaging (MRI). The usual approach, based on iron induced changes in magnetic relaxation (T2/T2'), is often prone, however, to confounding artifacts and lacks specificity. Here, we propose a new method to quantify and map iron deposits using water diffusion MRI. This method is based on the differential sensitivity of two image acquisition schemes to the local magnetic field gradients induced by iron deposits and their cross-term with gradient pulses used for diffusion encoding. Iron concentration could be imaged and estimated with high accuracy in the brain cortex, the thalamus, the substantia nigra and the globus pallidus of macaques, showing iron distributions in agreement with literature. Additionally, iron maps could clearly show a dramatic increase in iron content upon injection of an UltraSmall Particle Iron Oxide (USPIO) contrast agent, notably in the cortex and the thalamus, reflecting regional differences in blood volume. The method will benefit clinical investigations on the effect of iron deposits in the brain or other organs, as iron deposits are increasingly seen as a biomarker for a wide range of diseases, notably, neurodegenerative diseases in the pre-symptomatic stage. It also has the potential for quantifying variations in blood volume induced by brain activation in fMRI studies using USPIOs.
authors.affiliation: Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Department of Neurosurgery, Iwate Medical University, 19-1 Uchimaru, Morioka, 0208505 Iwate, Japan.
authors.forename: Shunro
authors.initials: S
authors.lastname: Fujiwara
authors.affiliation: Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Equipe Avenir INSERM Bettencourt Schueller, Institut Fédératif de Recherche n°49, NeuroSpin, Bât. 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France.
authors.forename: Lynn
authors.initials: L
authors.lastname: Uhrig
authors.affiliation: Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Amadon
authors.affiliation: Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Equipe Avenir INSERM Bettencourt Schueller, Institut Fédératif de Recherche n°49, NeuroSpin, Bât. 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Department of Neurosurgery, Neuromodulation unit, Foch Hospital, University of Versailles-Saint Quentin, 40 rue Worth, 92150 Suresnes, France.
authors.forename: Béchir
authors.initials: B
authors.lastname: Jarraya
authors.affiliation: Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France. Electronic address: denis.lebihan@gmail.com.
authors.forename: Denis
authors.initials: D
authors.lastname: Le Bihan
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D038524:Diffusion Magnetic Resonance Imaging; D007501:Iron / Q000032:analysis*; D008253:Macaca mulatta; D008297:Male; D059906:Neuroimaging
chemical_list: D007501:Iron
keywords: Diffusion MRI; Iron deposits; Magnetic resonance imaging (MRI); Neurodegenerative disease; Non-human primates