WHITE MATTER INJURY IN NEWBORNS WITH CARDIAC DISEASE

Objective : Neurodevelopmental impairment is common in term newborns with congenital heart disease (CHD), yet the mechanism and timing of brain injury in this population is largely unknown.

Methods : We are studying brain injury and development in a prospective cohort of term newborns with congenital heart disease using advanced magnetic resonance (MR) imaging techniques before and after heart surgery: high resolution MR imaging, diffusion tensor imaging, and MR spectroscopic imaging.

Results : In term newborns with CHD, the characteristic brain injury observed on preoperative MRI is stroke. The clinical risk factor most strongly associated with preoperative brain injury is balloon atrial septostomy, a life-saving procedure for some babies with transposition of the great arteries. Data from our group and others have found white matter injury in up to one half of term newborns with CHD postoperatively. The predominance of white matter injury is surprising as hypoxic-ischemic insults in the term newborn are expected to result in predominant injury to the deep gray nuclei and intervascular boundary zones. The development of white matter pathways may also be impaired by preoperative brain injury, as demonstrated using diffusion tensor imaging and MR spectroscopic imaging.

Conclusions: The timing of brain injury in the newborn with congenital heart disease is complex. The high frequency of white matter injury suggests an unusual vulnerability of the white matter in these term newborns. MR brain imaging provides a unique window on the timing and nature of brain injury that can be used to optimally design and test emerging strategies of brain protection in this high-risk population.

Keywords: Brain Injury, Stroke, White Matter Injury, Congenital Heart Disease, MRI, Diffusion Tensor Imaging, Tractography, MR Spectroscopy