Investigation of Post-Mortem Magnetic Resonance Imaging for the Detection of Intraneural Hemorrhage

As submitted by the proposer: Although rare, when pediatric cervical spine injuries occur, they frequently result in significant morbidity and/or mortality. Furthermore, in cases of pediatric trauma where the manner of injury (inflicted vs. accidental) is in question, these cases take on heightened importance. Unfortunately, because cervical spine injuries are rare, the methods for evaluating these injuries are not as familiar to most practitioners (physicians or pathologists) and are not as thoroughly developed, validated, or standardized, relative to assessments of head trauma. A number of experts speculate that the incidence of spinal injuries is actually greater than reported, because spinal injuries are more difficult to assess and are more-easily overlooked, particularly in cases where multiple injuries are present. Further, detailed dissection and histological evaluation of the cervical spine, nerve roots, and surrounding tissue is a complex and time consuming procedure. The genesis and evaluation of inflicted pediatric neurotrauma including the relationship of neck trauma to cerebral findings (particularly in cases without clear evidence of impact to the head) is currently controversial. Consequently, developing reliable, non-invasive methods to rapidly detect and assess pediatric cervical spine trauma is a critical need, in both the clinical and forensic settings. Due to the elasticity of the pediatric spinal column, cervical injuries may result in nerve injury without the skeletal dislocations or fractures which would be easily-detected by Computed Tomography (CT). Owing to the superior soft-tissue contrast of Magnetic Resonance (MR) imaging, MR is often cited as a superior method for the non-invasive assessment of spinal cord and nerve injuries. However, that the evidence for the superiority of MR (relative to CT) in assessing pediatric nerve injuries is mainly presented in isolated case studies. Due to a paucity of pediatric cases, there is a resulting lack of systematic studies to determine the optimum MR imaging protocols for evaluating pediatric spinal nerve trauma. Furthermore, in small children and infants, non-invasive imaging of the cervical spine is quite challenging, as the relevant anatomic structures (e.g., cervical nerve roots, thin fluid layers) are small in size and do not typically lie in convenient imaging planes amenable to standard slice-selective (2D) MR imaging techniques. Our over-arching hypothesis is that three-dimensional (3D) post-mortem Magnetic Resonance (PMMR) can be optimized to enable visualization of intraneural hemorrhage at a resolution useful for future application to the assessment of the cervical spine in infants and small children. In this basic research study, we propose to optimize PMMR spatial resolution and image contrast in a thorough and systematic way using phantoms and ex vivo tissue samples infused with blood and degraded blood components. We then propose to test optimized PMMR detection protocols in rat models of intraneural hemorrhages of various antemortem ages. The successful completion of these proposed basic imaging studies will result in MR protocols, optimized and validated for detecting intraneural hemorrhage, that could be applied in future studies involving rare but often high-stakes cases in which living or deceased pediatric subjects present with suspected neural trauma. ca/ncf