title: Serial Diffusion Tensor Imaging In Vivo Predicts Long-Term Functional Recovery and Histopathology in Rats following Different Severities of Spinal Cord Injury.
abstract: The current study demonstrates the feasibility of using serial magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) in vivo to quantify temporally spinal cord injury (SCI) pathology in adult female Sprague-Dawley rats that were scanned prior to a moderate or severe upper lumbar contusion SCI. Injured rats were behaviorally tested for hind limb locomotion (Basso, Beattie, Bresnahan [BBB] scores) weekly for 4 weeks and scanned immediately after each session, ending with terminal gait analyses prior to euthanasia. As a measure of tissue integrity, fractional anisotropy (FA) values were significantly lower throughout the spinal cord in both injury cohorts at all time-points examined versus pre-injury. Moreover, FA values were significantly lower following severe versus moderate SCI at all time-points, and FA values at the injury epicenters at all time-points were significantly correlated with both spared white and gray matter volumes, as well as lesion volumes. Critically, quantified FA values at subacute (24 h) and all subsequent time-points were highly predictive of terminal behavior, reflected in significant correlations with both weekly BBB scores and terminal gait parameters. Critically, the finding that clinically relevant subacute (24 h) FA values accurately predict long-term functional recovery may obviate long-term studies to assess the efficacy of therapeutics tested experimentally or clinically. In summary, this study demonstrates a reproducible serial MRI procedure to predict the long-term impact of contusion SCI on both behavior and histopathology using subacute DTI metrics obtained in vivo to accurately predict multiple terminal outcome measures, which can be particularly valuable when comparing experimental interventions.
authors.affiliation: 1 Spinal Cord and Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.|2 Department of Physiology, University of Kentucky , Lexington, Kentucky.
authors.forename: Samir P
authors.initials: SP
authors.lastname: Patel
authors.affiliation: 1 Spinal Cord and Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.
authors.forename: Taylor D
authors.initials: TD
authors.lastname: Smith
authors.affiliation: 1 Spinal Cord and Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.|2 Department of Physiology, University of Kentucky , Lexington, Kentucky.
authors.forename: Jenna L
authors.initials: JL
authors.lastname: VanRooyen
authors.affiliation: 4 Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky , Lexington, Kentucky.|5 Department of Biomedical Imaging, University of Kentucky , Lexington, Kentucky.
authors.forename: David
authors.initials: D
authors.lastname: Powell
authors.affiliation: 1 Spinal Cord and Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.
authors.forename: David H
authors.initials: DH
authors.lastname: Cox
authors.affiliation: 1 Spinal Cord and Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.|3 Department of Anatomy and Neurobiology, University of Kentucky , Lexington, Kentucky.
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Sullivan
authors.affiliation: 1 Spinal Cord and Brain Injury Research Center, University of Kentucky , Lexington, Kentucky.|2 Department of Physiology, University of Kentucky , Lexington, Kentucky.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Rabchevsky
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D056324:Diffusion Tensor Imaging / Q000592:standards*; D004195:Disease Models, Animal; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000293:injuries; D009069:Movement Disorders / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000502:physiology*; D013119:Spinal Cord Injuries / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology
keywords: BBB; anisotropy; contusion; gait analysis; magnetic resonance imaging (MRI); neuroimaging; white matter