UC Berkeley

Background

Previous studies using diffusion tensor imaging (DTI)-based connectome analysis revealed improved connectivity in cerebral palsy (CP) patients who underwent autologous umbilical cord blood (UCB) stem-cell therapy. However, the potential mechanism for the connectivity increase remains unclear and needs to be further elucidated.

Purpose

To develop a technique with improved accuracy for quantitative susceptibility mapping (QSM) with unique sensitivity to myelin, and demonstrate its use in elucidating the underlying mechanism of the observed motor function improvement and brain connectivity increase in CP patients who received autologous UCB stem-cell therapy.

Study type

Prospective.

Population

A cohort of eight pediatric CP patients (2.6 ± 0.6 years of age) with intact corticospinal tracts (CST) from a randomized, placebo-controlled trial of autologous UCB stem-cell therapy in CP children was included in this study.

Field strength/sequence

DTI and 3D spoiled gradient recalled (SPGR) QSM at 3.0T.

Assessment

Pre- and posttreatment magnetic susceptibility (χ) and the rotationally-invariant magnetic susceptibility anisotropy (MSA) along the CST were derived. Behavioral changes were assessed using the 66-item Gross Motor Function Measurement. Changes in χ and MSA were compared between patients with and without substantial behavioral improvements.

Statistical tests

Two-sample t-tests were performed to assess the differences in the changes of measurements of interest (Δχ, ΔMSA, and ΔFA) between patients who significantly improved and those who did not.

Results

Patients who demonstrated posttreatment motor improvements exceeding expectations showed significantly more diamagnetic Δχ in the periventricular region along the CST (P = 0.003). Further analysis on the ΔMSA of this region was significantly increased (P = 0.006) for high responders, along with concurrent FA increase.

Data conclusion

These initial findings suggest that the DTI tract-based QSM method has the potential to characterize white matter changes associated with behavioral improvements in CP children who underwent cord blood stem-cell therapy.

Level of evidence

2 TECHNICAL EFFICACY: Stage 2.