Porcine Model of the Growing Spinal Cord—Changes in Diffusion Tensor Imaging Parameters

SIMPLE SUMMARY: Spinal cord injuries are a great concern in veterinary and human medicine. The main problem in this field is the difficulty of evaluating the degree of damage objectively using standard structural imaging methods. In our work, we used an advanced imaging technique that has promising applications for the objective assessment of the microstructure of the spinal cord. We decided to apply this method to healthy pigs as a model organism due to their rapid weight gain and anatomical and physiological similarity to humans. We obtained results that could be useful in determining reference values for the undamaged spinal cords of animals and growing humans. The obtained values related to porcine growth will allow us to achieve a model of the growing spinal cord that can be used in both human and veterinary medicine for the objective assessment of the microstructure of the spinal cord. ABSTRACT: Diffusion tensor imaging (DTI) is an advanced magnetic resonance imaging (MRI) technique that has promising applications for the objective assessment of the microstructure of the spinal cord. This study aimed to verify the parameters obtained using DTI change during the growth process. We also wanted to identify if the DTI values change on the course of the spinal cord. The model organism was a healthy growing porcine spinal cord (19 pigs, Polish White, weight 24–120 kg, mean 48 kg, median 48 kg, age 2.5–11 months, mean 5 months, median 5.5 months). DTI parameters were measured in three weight groups: up to 29 kg (five pigs), 30–59 kg (six pigs), and from 60 kg up (eight pigs). DTI was performed with a 1.5 Tesla magnetic resonance scanner (Philips, Ingenia). Image post-processing was done using the Fiber Track package (Philips Ingenia workstation) by manually drawing the regions of interest (nine ROIs). The measurements were recorded for three sections: the cervical, thoracolumbar and lumbar segments of the spinal cord at the C4/C5, Th13/L1, and L4/L5 vertebrae levels. In each case, one segment was measured cranially and one caudally from the above-mentioned places. The values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were obtained for each ROIs and compared. It is shown that there is a correlation between age, weight gain, and change in FA and ADC parameters. Moreover, it is noted that, with increasing weight and age, the FA parameter increases and ADC decreases, whereas the FA and ADC measurement values did not significantly change between the three sections of the spinal cord. These findings could be useful in determining the reference values for the undamaged spinal cords of animals and growing humans.