Tissue- and column-specific measurements from multi-parameter mapping of the human cervical spinal cord at 3 T

The aim of this study was to quantify a range of MR parameters [apparent proton density, longitudinal relaxation time T-1, magnetisation transfer (MT) ratio, MT saturation (which represents the additional percentage MT saturation of the longitudinal magnetisation caused by a single MT pulse) and apparent transverse relaxation rate R-2*] in the white matter columns and grey matter of the healthy cervical spinal cord. The cervical cords of 13 healthy volunteers were scanned at 3 T using a protocol optimised for multi-parameter mapping. Intra-subject co-registration was performed using linear registration, and tissue- and column-specific parameter values were calculated. Cervical cord parameter values measured from levels C1-C5 in 13 subjects are: apparent proton density, 4822 +/- 718 a.u.; MT ratio, 40.4 +/- 1.53 p.u.; MT saturation, 1.40 +/- 0.12 p.u.; T-1=1848 +/- 143 ms; R-2*=22.6 +/- 1.53 s(-1). Inter-subject coefficients of variation were low in both the cervical cord and tissue- and column-specific measurements, illustrating the potential of this method for the investigation of changes in these parameters caused by pathology. In summary, an optimised cervical cord multi-parameter mapping protocol was developed, enabling tissue- and column-specific measurements to be made. This technique has the potential to provide insight into the pathological processes occurring in the cervical cord affected by neurological disorders. (c) 2013 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.