Dynamic diffusion tensor imaging of spinal cord contusion: A canine model

Abstract

This study aimed to explore the dynamic diffusion tensor imaging (DTI) of changes in spinal cord contusion using a canine model of injury involving rostral and caudal levels. In this study, a spinal cord contusion model was established in female dogs using a custom-made weight-drop lesion device. DTI was performed on dogs with injured spinal cords (n=7) using a Siemens 3.0T MRI scanner at pre-contusion and at 3 h, 24 h, 6 weeks and 12 weeks post-injury. The tissue sections were stained for immunohistochemical analysis. Canine models of spinal cord contusion were created successfully using the weight-drop lesion device. The fractional anisotropy (FA) value of lesion epicenter decreased, while the apparent diffusion coefficient (ADC), mean diffusivity (MD), and radial diffusivity (RD) values increased, and the extent of the curve was apparent gradually. The site and time affected the DTI parameters significantly in the whole spinal cord, ADC (site, P < 0.001 and time, P = 0.077, respectively); FA (site, P < 0.001 and time, P = 0.002, respectively). Immunohistological analysis of GFAP and NF revealed the pathologic changes of reactive astrocytes and axons, as well as the cavity and glial scars occurring during chronic SCI. DTI is a sensitive and noninvasive imaging tool useful to assess edema, hemorrhage, cavity formation, structural damage and reconstruction of axon, and myelin in dogs. The DTI parameters after contusion vary. However, the curves of ADC, MD, and RD were nearly similar and the FA curve was distinct. All the DTI parameters were affected by distance and time.

Degeneration of white matter and gray matter revealed by diffusion tensor imaging and pathological mechanism after spinal cord injury in canine

“…The bilateral hind limbs showed flaccid paralysis after dissipation of the effect of anesthesia. The gait and postural reactions remained scoreless, and nociception in each limb showed one point within 2 days, suggesting in the successful creation of the model …”

“…At the rostral and caudal levels, the reactive glial cells proliferated and went beyond the gray matter area. Based on the figures from Liu et al…”

“…Vertebral laminae of T10 and part of T9 and T11 vertebra were uncovered to expose a 1‐cm‐long spinal cord. Five animals (underwent laminotomy without SCI) were considered as controls, and seven animals underwent SCI following the previously described method …”

“…The antibiotic agent cefoxitin sodium (50 mg/kg) was administered via intramuscular injection daily for seven consecutive days. The details were described previously …”

“…Five animals (underwent laminotomy without SCI) were considered as controls, and seven animals underwent SCI following the previously described method. 14…”