Atlas-Based Quantification of DTI Measures in a Typically Developing Pediatric Spinal Cord

Abstract

BACKGROUND AND PURPOSE: Multi-parametric MRI, provides a variety of biomarkers sensitive to white matter integrity, However, spinal cord MRI data in pediatrics is rare compared to adults. The purpose of this work was 3-fold: 1) to develop a processing pipeline for atlasbased generation of the typically developing pediatric spinal cord WM tracts, 2) to derive atlas-based normative values of the DTI indices for various WM pathways, and 3) to investigate age-related changes in the obtained normative DTI indices along the extracted tracts.MATERIALS AND METHODS: DTI scans of 30 typically developing subjects (age range, 6-16 years) were acquired on a 3T MR imaging scanner. The data were registered to the PAM50 template in the Spinal Cord Toolbox. Next, the DTI indices for various WM regions were extracted at a single section centered at the C3 vertebral body in all the 30 subjects. Finally, an ANOVA test was performed to examine the effects of the following: 1) laterality, 2) functionality, and 3) age, with DTI-derived indices in 34 extracted WM regions. RESULTS:A postprocessing pipeline was developed and validated to delineate pediatric spinal cord WM tracts. The results of ANOVA on fractional anisotropy values showed no effect for laterality (P ¼ .72) but an effect for functionality (P , .001) when comparing the 30 primary WM labels. There was a significant (P , .05) effect of age and maturity of the left spinothalamic tract on mean diffusivity, radial diffusivity, and axial diffusivity values. CONCLUSIONS:The proposed automated pipeline in this study incorporates unique postprocessing steps followed by template registration and quantification of DTI metrics using atlas-based regions. This method eliminates the need for manual ROI analysis of WM tracts and, therefore, increases the accuracy and speed of the measurements.

Diffusion tensor imaging of fetal spinal cord: feasibility and gestational‐age‐related changes

“…This study demonstrates increasing FA and constant ADC values between 22 and 36 weeks of gestation, which may be attributed to the normal myelination process of the spinal cord that starts at the end of the first trimester of pregnancy and continues into adolescence 35 . Moreover, this study shows a similar pattern to that reported in a pediatric study, which demonstrated an age-related increase in FA of the spinal cord in 23 subjects ranging in age from 6 to 16 years 14,36 .…”

Reproducible Spinal Cord Quantitative MRI Analysis with the Spinal Cord Toolbox

“…Note that the PAM50 spinal cord template is aligned with the ICBM-152 “MNI” brain template, 69 allowing researchers to perform simultaneous brain and spinal cord studies within the same referential system. 70 – 73 The white and gray matter spinal cord atlas was used for tract-specific analysis in amyotrophic lateral sclerosis, 17 degenerative cervical myelopathy, 34 traumatic spinal cord injury, 74 Friedreich’s Ataxia, 18 and pediatric population. 75 Other studies used the PAM50 template and atlas to create a spatial distribution of spinal cord lesions in multiple sclerosis and degenerative cervical myelopathy.…”

“… 70 – 73 The white and gray matter spinal cord atlas was used for tract-specific analysis in amyotrophic lateral sclerosis, 17 degenerative cervical myelopathy, 34 traumatic spinal cord injury, 74 Friedreich’s Ataxia, 18 and pediatric population. 75 Other studies used the PAM50 template and atlas to create a spatial distribution of spinal cord lesions in multiple sclerosis and degenerative cervical myelopathy. 72 , 76 , 77 …”