title: ZOOM or Non-ZOOM? Assessing Spinal Cord Diffusion Tensor Imaging Protocols for Multi-Centre Studies.
abstract: The purpose of this study was to develop and evaluate two spinal cord (SC) diffusion tensor imaging (DTI) protocols, implemented at multiple sites (using scanners from two different manufacturers), one available on any clinical scanner, and one using more advanced options currently available in the research setting, and to use an automated processing method for unbiased quantification. DTI parameters are sensitive to changes in the diseased SC. However, imaging the cord can be technically challenging due to various factors including its small size, patient-related and physiological motion, and field inhomogeneities. Rapid acquisition sequences such as Echo Planar Imaging (EPI) are desirable but may suffer from image distortions. We present a multi-centre comparison of two acquisition protocols implemented on scanners from two different vendors (Siemens and Philips), one using a reduced field-of-view (rFOV) EPI sequence, and one only using options available on standard clinical scanners such as outer volume suppression (OVS). Automatic analysis was performed with the Spinal Cord Toolbox for unbiased and reproducible quantification of DTI metrics in the white matter. Images acquired using the rFOV sequence appear less distorted than those acquired using OVS alone. SC DTI parameter values obtained using both sequences at all sites were consistent with previous measurements made at 3T. For the same scanner manufacturer, DTI parameter inter-site SDs were smaller for the rFOV sequence compared to the OVS sequence. The higher inter-site reproducibility (for the same manufacturer and acquisition details, i.e. ZOOM data acquired at the two Philips sites) of rFOV compared to the OVS sequence supports the idea that making research options such as rFOV more widely available would improve accuracy of measurements obtained in multi-centre clinical trials. Future multi-centre studies should also aim to match the rFOV technique and signal-to-noise ratios in all sequences from different manufacturers/sites in order to avoid any bias in measured DTI parameters and ensure similar sensitivity to pathological changes.
authors.affiliation: NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Samson
authors.affiliation: Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada.|Functional Neuroimaging Unit, University of Montreal, Montreal, QC, Canada.
authors.forename: Simon
authors.initials: S
authors.lastname: Lévy
authors.affiliation: NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom.|Philips Healthcare, Guilford, Surrey, United Kingdom.
authors.forename: Torben
authors.initials: T
authors.lastname: Schneider
authors.affiliation: Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, Tennessee, United States of America.|Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Alex K
authors.initials: AK
authors.lastname: Smith
authors.affiliation: Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, Tennessee, United States of America.|Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, United States of America.|Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Seth A
authors.initials: SA
authors.lastname: Smith
authors.affiliation: Institute of Biomedical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada.|Functional Neuroimaging Unit, University of Montreal, Montreal, QC, Canada.
authors.forename: Julien
authors.initials: J
authors.lastname: Cohen-Adad
authors.affiliation: NMR Research Unit, Queen Square MS Centre, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom.|Brain MRI 3T Center, C. Mondino National Neurological Institute, Pavia, Italy.|Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy.
authors.forename: Claudia A M
authors.initials: CA
authors.lastname: Gandini Wheeler-Kingshott
mesh_terms: D016880:Anisotropy; D004058:Diffusion; D056324:Diffusion Tensor Imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013116:Spinal Cord / Q000473:pathology*