Actively decouled two coil system enables in vivo

Introduction Rodents have been widely used as the animal model of various human diseases and injuries. With the readily achievable gene manipulation, transgenic mice have been employed to study diseases like amyotrophic lateral sclerosis, multiple sclerosis, or spinal cord injury (1). For the in vivo examination of degenerative disease, MRI has been extensively used in human patients and animal models. Recent work suggests that in vivo MRdiffusion measurements can detect disease in brain and spinal cord white matter with appropriate histology validation (2-4). Since neurodegeneration may be extended from the brain to the cervical spinal cord, a reliable methodology of in vivo DTI for cervical spinal cord is needed. EPI-DTI has been used to obtain diffusion measurements from rodent spinal cords at highg field strengths, 7, 9.4, and 12 T, taking the advantage of short data acquisition time. Here we present in vivo DTI measurements for mouse cervical spinal cord at magnetic field strength of 4.7 T using the custom-made actively decoupled volume and surface coil. Homogeneous B1 magnetic field and improved SNR were expected by using volume and surface coil as RF excitation and signal receiver, respectively. The acquired DTI maps (relative anisotropy (RA), axial (λ||) and radial (λ⊥) diffusivity, and trace of the diffusion tensor (Tr(D)) provide detailed structural information on brain stem and cervical spinal cord. Methods