Adolescents with d-transposition of the great arteries repaired in early infancy demonstrate reduced white matter microstructure associated with clinical risk factors

Objective Our objective was to use diffusion tensor imaging (DTI) to compare white matter microstructure in adolescents with d-transposition of the great arteries (d-TGA) who underwent the arterial switch operation in early infancy with typically developing control adolescents. We also examined correlates between patient demographic and medical risk factors and white matter as assessed by regional fractional anisotropy (FA) values. Methods We used with magnetic resonance imaging (MRI) to study 49 adolescents with d-TGA and 29 control adolescents. MRI data, including whole brain DTI and conventional anatomic MRI, were acquired from each subject. Each subject's data were analyzed using random effects analysis to evaluate regional white matter differences in FA between d-TGA and control adolescents. Results While multifocal punctate MRI hypointensities on T1-weighted (T1W) imaging suggestive of mineralization were found, other evidence of gross white matter injury was absent. Eighteen discrete regions of significantly reduced FA in d-TGA adolescents compared with controls were observed in deep white matter of cerebral hemispheres, cerebellum, and midbrain. Among d-TGA adolescents, lower FA correlated with younger gestational age, shorter duration of intraoperative cooling, higher intraoperative minimum tympanic temperature, longer intensive care unit stay after repair, and greater total number of open cardiac operations. Conclusions Despite scant white matter injury evident on conventional brain MRI, adolescents with d-TGA repaired in infancy demonstrate significant white matter FA reduction that may relate to their reported neurocognitive deficits. Among adolescents with d-TGA, FA values are associated with patient and perioperative factors, some of which are modifiable.