Title: in vivo short TE localized 1 H MR spectroscopy of mouse cervical spinal cord at very high magnetic field (11.75T)

• Tachrount Mohamed
• Duhamel Guillaume
• Laurin Jérôme J
• Marqueste Tanguy
• Maues de Paula André
• Decherchi Patrick
• Cozzone Patrick J
• Callot Virginie
• Tachrount Mohamed

• Proton MRS
• Short TE
• Very high magnetic field
• Mouse
• Cervical spinal cord

MR spectroscopy allows a noninvasive assessment of metabolic information in healthy and pathological central nervous system. Whereas MR spectroscopy has been extensively applied in the brain, only few spectroscopic studies of the spinal cord (SC) have been performed so far. For mice, due to additional technical challenges, in vivo 1H SC MRS has not yet been reported. In this work, the feasibility of short echo time localized proton magnetic resonance spectroscopy using Point RESolved Spectroscopy sequence for the examination of mouse cervical SC at 11.75 T is presented. Several optimizations were performed to improve the static field homogeneity, to reduce physiological motion effects and lipid contaminations arising from SC surrounding tissues, and to provide a careful metabolic quantification. Satisfactory spectrum quality was obtained. The described protocol allowed reliable quantification of five metabolites in the cervical SC. The mean reproducibility regarding the quantification of tNAA, tCr and tCho was ≥ 80%, > 70% for mI and > 55% for Glu, whereas the intersubject variabilities were ≤ 21%. The application of this protocol to transgenic mouse models in pathological conditions such as SC injury or neurodegenerative diseases may thus provide complementary information to MRI and increase our understanding of such pathologies.