Introduction: We present a comprehensive analysis of diffusion tensor MR imaging (DTI) in spinal cord injury (SCI). Translational experiments were performed in rats and humans with SCI. DTI indices derived fron the SCI 'zone' and distal spinal cord segments are presented. A rationale for incorporation of DTI as a new noninvasive prognostic and diagnostic tool in SCI patients is discussed
Methods: Animal experiments used cohorts of rats imparted with moderate thoracic SCI using an NYU Impactor. Human studies were conducted on a cohort of SCI patients and controls. Animal imaging studies were performed using a Bruker 9.4T scanner. Human imaging was conducted using a 1.5T clinical scanner
Results: Aniaml studies showed a significant temporal and spatial correlation of DTI indices lADC, tADC and MD at the zone of injury. MD was also significantly reduced in the cervical spinal cord after injury. The change in DTI indices at the injury zone and in the cervical spinal cord correlated with postmortem histology. lADC was also noted to correlate significantly with changes in amplitude of spinal somatosensory evoked potentials after injury.
Human studies showed a characteristic pattern of FA throughout the normal spinal cord. As observed in animal studies, lADC, tADC and MD chaged in a predictable fashion both temporally and spatially at the injury zone. Further, MD was significantly lower in cervical cord after SCI
Conclusions: We present comprehensive data validating DTI as a novel method that may provide reliable biomarkers for tissue changes in the entire spinal cord after SCI. Further, we demonstrate that DTI indices correlate well with known measures of spinal cord function after SCI. We believe that DTI can be a valuable tool to better estimate prognosis in SCI patients. Further, we recommend based on these studies that DTI should be considered as an imaging paradigm in forthcoming transplantation studies for SCI patients.
Patient Care: The incorporation of DTI into routine MR Imaging protocols in SCI patients will provide reliable non invasive biomarkers to better estimate prognosis and guide therapeutic interventions in the unfortunate patient population
Learning Objectives: At the conclusion of this presentation, participants should be able to 1)perceive the evolution of DTI as a new and clinically important tool to assess SCI prognosis as well as 2)a guide to noninvasively follow the effect of new transplantation therapies for SCI
References: 1. Lesion growth and degeneration patterns measured using diffusion tensor 9.4-T magnetic resonance imaging in rat spinal cord injury.Ellingson BM, Schmit BD, Kurpad SN.J Neurosurg Spine. 2010 Aug;13(2):181-92.
2. Functional correlates of diffusion tensor imaging in spinal cord injury. Ellingson BM, Kurpad SN, Schmit BD.
Biomed Sci Instrum. 2008;44:28-33.