ACQUISITION, PROCESSING, AND ANALYSIS OF DIFFUSION TENSOR IMAGING AND ATROPHY MRI IN THE INJURED PEDIATRIC SPINAL CORD

Abstract

Spinal cord injury has the potential to be debilitating, particularly in the pediatric population. Identification of the exact injury level can be difficult from conventional structural Magnetic Resonance Imaging (MRI) scans, and younger children often have difficulty in participating in the clinical examinations that define neurologic damage. Because of limitations of existing clinical examinations and conventional imaging, more advanced quantitative imaging techniques are important for improvement in diagnostic and prognostic evaluation of spinal cord injury. A quantitative characterization of the full spinal cord injury from both a functional and structural perspective has not been performed in pediatric subjects and has potential to provide important diagnostic and prognostic information. Diffusion tensor imaging (DTI) gives a non-invasive quantification of water diffusion in the spinal cord and can provide insight into white matter integrity, while high resolution volumetric imaging can determine cord cross sectional area reflecting atrophy occurring post injury. Multiple challenges exist in analysis of pediatric spinal cord data, including physiological motion, low signal-to-noise, thermal noise and image artifact, and cumbersome measurements of cord morphology. In this work, a complete pipeline for the acquisition and analysis of both functional DTI data and high resolution structural data is designed, tested, and implemented including MR image acquisition, motion correction, diffusion tensor estimation, region of interest analysis, and semi-automated cord cross sectional area measurement. Data for both healthy subjects and subjects with spinal cord injury is collected and significant correlations are shown between DTI and cord morphology metrics. This characterization of the injured spinal cord using both structural and functional data has the potential to offer important new information for examination of spinal cord injury.