Purpose: 1) To evaluate the maturational evolution of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the normal pediatric cervical as well as upper thoracic cord, 2) to evaluate whether ADC and FA values vary at different levels within the spinal cord [upper cervical (UC), lower cervical (LC) and upper thoracic (UT)].
Methods: Normal pediatric MRI and diffusion tensor imaging (DTI) studies of the spinal cord obtained with a 1.5 Tesla MR scanner were retrospectively analyzed. ADC and FA maps were reconstructed from the DTI data. Regions of interest were manually placed at the center of the cervical and upper thoracic cord at the intervertebral disk levels in mid-sagittal plane. The ADC and FA values were analyzed by linear regression and a general linear model with repeated measures.
Results: Forty-seven subjects ranged in age from 2 months-17.5 years (mean ± standard deviation: 74.3 ± 61.1 months) were included in the study. At all spinal cord levels a statistically significant decrease in ADC and increase in FA with increasing child’s age was evident. The ADC values of the UC/LC levels were higher than those of UT while the FA values did not show significant differences.
Conclusion: DTI scalars vary with age, likely due to ongoing maturational processes, and ADC values vary across levels of the spinal cord. Consequently when quantitative DTI of the spinal cord is undertaken in children; an age and levelmatched normative data should be used to accurately interpret the quantitative results.
Izlem Izbudak, Netsiri Dumrongpisutikul, Carol B Thompson, Aylin Tekes, Majda Thurnher and
Thierry AGM Huisman