Post-mortem diffusion MRI of the cervical spine and its nerve roots

Abstract

Purpose: The aim of this work is to examine the architectural configuration and the microstructural substrate of the cervical spine and its nerve roots with post-mortem (PM) diffusion tensor imaging (DTI) in non-fixed subjects and to compare these findings with histology. Methods: Magnetic resonance imaging (MRI) data were acquired on a 1.5 T MRI scanner in five non-fixed non-trauma deaths. Two different areas were evaluated: 1) the cervical spinal cord and ventral and dorsal nerve roots with a "high in-plane" DTI and a multi-echo fast field echo protocol, and 2) the cervical peripheral nerves with an "isotropic" DTI and a 3D turbo spin echo protocol. Histology samples were obtained matching the anatomical level of the slices of the 'high in-plane' DTI protocol. Results: We were able to show detailed reconstructions of the dorsal and ventral nerve roots with the 'high in-plane' protocol and identified a low fractional anisotropy (FA = 0.30 ± 0.08) in the grey matter and a high FA (0.51 ± 0.13) in the white matter. Both grey and white matter configurations correlated with the anatomical MRI, the diffusion MRI, and with the histological sections. Using the 'isotropic' DTI protocol, it was feasible to reconstruct the spinal cord, cervical nerves, and nerve roots in all PM subjects. Conclusion: We were able to generate detailed architectural configurations of the ventral and dorsal nerve roots. Anatomical and diffusion MR scans showed good qualitative agreement with histology. We believe that PMDTI will be helpful in the assessment of head and neck injuries in a forensic setting.