# Magnetization Transfer Ratio in the Typically Developing Pediatric Spinal Cord: Normative Data and Age Correlation

## TL;DR

This study provides normative data on magnetization transfer ratios in the spinal cords of healthy children and shows how these values change with age and sex.

## Contribution

The study introduces automated atlas-based MTR measurements for the pediatric cervical spinal cord and reports age and sex correlations.

## Key findings

- MTR values showed significant sex differences in whole white matter and lateral corticospinal tracts.
- MTR values at C5 correlated positively with age after correcting for multiple comparisons.
- A decreasing trend in MTR values was observed across spinal cord levels in whole white matter.

## Abstract

This study presents automated atlas‐based magnetization transfer (MT) measurements of the typically developing pediatric cervical spinal cord (SC). We report normative MT ratio (MTR) values from the whole cervical cord white matter (WM) and WM tracts, examining variations with age, sex, height, and weight.

MT scans of 33 healthy females (mean age = 12.8) and 22 males (mean age = 13.09) were acquired from the cervical SC (C2–C7) using a 3.0 T MRI. Data were processed using the SC Toolbox, segmented, and registered to the PAM50 template. Affine and non‐rigid transformations co‐registered the PAM50 WM atlas to subject‐specific space. MTRs were measured for the specific WM tracts (left and right dorsal fasciculus gracilis, dorsal fasciculus cuneatus, and lateral corticospinal tracts [LCST]) and the whole WM. Descriptive statistics, correlation analysis, and unpaired t‐tests (p < 0.05) assessed relationships with age, height, weight, and sex.

Normative MTR measurements were obtained from all regions. The coefficients of variation were low to moderate. No significant differences (p > 0.05) were found across all the cervical levels. However, significant sex differences were observed in whole WM (p = 0.04) and LCST (p = 0.03). MTR values correlated positively with age, with significant correlations at C5 (r = 0.3, p false discovery rate = 0.04). A decreasing trend in MTR values across levels was found for whole WM (r = −0.2, p < 0.001).

This study provides an understanding of MTR values in pediatric cervical SC and their variations by sex, age, height, and weight, providing a baseline for comparisons in pediatric SC diseases.