Diffusion tensor imaging predicts motor outcome in children with acquired brain injury.

Background: Rehabilitation in children with acquired brain injury is a challenging endeavour. There is a large variability in motor recovery between patients, and a need to optimize therapies by exploiting cerebral plasticity and recovery mechanisms. This retrospective study aims to identify tract-based markers that could serve as predictors of functional outcome following rehabilitation.

Methods: Twenty-nine children with traumatic brain injury (n = 14) or stroke (n = 15) underwent a 3 T Magnetic Resonance Imaging (MRI) measurement, including Diffusion Tensor Imaging (DTI) between admission to the Hospital and onset of rehabilitation therapy at the Rehabilitation Centre. The Functional Independence Measure for Children (WeeFIM) was routinely applied at admission and discharge from the Rehabilitation Centre. Distinguishing between children with good versus poor functional independence was performed using ROC-analysis. A non-parametric partial correlation analysis between the DTI and WeeFIM motor scores was performed with age, time in rehabilitation, and time of MRI scan after injury as covariates.

Results: Mean fractional anisotropy (FA) from the DTI in the ipsilesional corticospinal-tract provided the highest predictive accuracy (sensitivity = 95 %, specificity = 78 %, Youden Index = 0.73, Area under the curve = 0.9), in comparison to the lesion volume or other clinical variables. Mean FA of the ipsilesional corticospinal-tract correlated positively with the WeeFIM discharge motor scores (ρ = 0.547, p = 0.004). Prediction was poorer for the lesion volume or Glasgow Coma Scale.

Conclusion: The results suggest that DTI data could improve the prediction of functional outcome after rehabilitation in children and adolescents with stroke or traumatic brain injury. Specifically, mean FA shows the highest predictive accuracy in comparison to lesion volume or clinical scales.