The corticospinal tract in Sturge-Weber syndrome: a diffusion tensor tractography study

OBJECTIVE: To utilize diffusion tensor tractography and evaluate the integrity of the corticospinal tract in children with unilateral Sturge-Weber syndrome (SWS). METHODS: Sixteen children (age: 1.5-12.3 years) with SWS involving one hemisphere and varying degrees of motor deficit, underwent magnetic resonance imaging (MRI) as part of a prospective clinical research study. Diffusion tensor imaging (DTI) was obtained and fiber tracking of the corticospinal tract was performed yielding average FA and ADC values along the pathway. These values were compared between the two hemispheres (affected vs. unaffected) and also correlated with the degree of motor deficits, after correction for age. RESULTS: Corticospinal tract FA values on the side of the affected hemisphere were lower (p=0.008) and ADC values were higher (p=0.011) compared to the normal side. Furthermore, FA and ADC values on the side of the angioma did not show the normal age-related variations, which the contralateral corticospinal pathway values did demonstrate. Although none of the patients had severe hemiparesis, those with moderate motor deficit had increased ADC values, as compared to those with mild (p=0.009) or no motor deficit (p=0.045). CONCLUSION: MRI with DTI shows abnormalities of the corticospinal tract in children with SWS even before severe motor impairment develops. Thus, DTI can be a clinically useful method to evaluate the integrity of the corticospinal tract in young children who are at risk for progressive motor dysfunction.