Children with unilateral cerebral palsy (UCP) due to early brain injury exhibit disrupted connectivity of corticospinal tracts (CSTs), which can be quantified using diffusion-weighted magnetic resonance imaging (DWI). Diffusion tensor imaging (DTI) is commonly used to quantify white matter organization, however, this model lacks the biological specificity to accurately describe underlying microstructural properties. Newer approaches, such as neurite orientation dispersion and density imaging (NODDI), may provide more biologically accurate information regarding CST microstructure. In this study, we directly compared metrics of CST microstructure using NODDI and DTI models to characterize the microstructural organization of corticospinal pathways. Twenty participants with UCP participating in a neuromodulation/rehabilitation intervention underwent imaging including multi-shell DWI; 10 participants' datasets were adequately completed for neuroimaging analysis. Task fMRI-guided probabilistic tractography from motor cortex to brainstem was performed at baseline and follow-up to reconstruct the CSTs. Diffusion metrics were compared between hemispheres at baseline, and between baseline and follow-up to test for intervention effects. Correlation analyses were used to compare baseline metrics to changes in hand function following the intervention. DTI results showed that mean fractional anisotropy in lesioned and nonlesioned CSTs did not significantly differ, but mean, axial, and radial diffusivity were greater in the lesioned CST. For NODDI, intracellular volume fraction (ICVF) and orientation dispersion index (ODI) were lower in the lesioned CST. Unimanual function was strongly correlated with ICVF, but not FA. NODDI may reveal distinct properties of CST microstructure that are linked to motor function, indicating their potential in characterizing brain structure and development.
Bibliographical noteFunding Information:
information Cerebral Palsy Foundation; Eunice Kennedy Shriver National Institute of Child Health and Human Development, Grant/Award Number: HD078484-01A1; Foundation for Physical Therapy; National Center for Advancing Translational Sciences, Grant/Award Numbers: KL2TR002492, UL1TR002494; National Institute of Biomedical Imaging and Bioengineering, Grant/Award Number: P41EB015894; NIH Office of the Director, Grant/Award Number: 1S10OD17974-01; University of Minnesota's Discovery, Research, and Innovation Economy (MnDRIVE) initiativeThe authors thank the participants and their families for their involvement. The authors also thank Drs Tonya Rich, Chao-Ying Chen, and Cecilia Prudente in data acquisition, and the Center for Magnetic Resonance Research (P41 EB015894 and 1S10OD017974-01) at the University of Minnesota. This study was funded the National Institutes of Health (NIH) Eunice Kennedy Shriver National Institutes of Child Health and Development K01 Award (HD078484-01A1), the Cerebral Palsy Foundation, the Foundation for Physical Therapy Magistro Family Grant, the University of Minnesota's Discovery, Research, and Innovation Economy (MnDRIVE) initiative, and the National Institutes of Health's National Center for Advancing Translational Sciences, grants KL2TR002492 and UL1TR002494. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health's National Center for Advancing Translational Sciences.
© 2019 Wiley Periodicals, Inc.
- corticospinal tract
- diffusion-weighted MRI
- neurite orientation dispersion and density imaging
- unilateral cerebral palsy