Background The objective was to determine the timing and mechanism of brain injury using preoperative and postoperative magnetic resonance imaging (MRI) and three-dimensional MR spectroscopic imaging (MRSI) in newborns with transposition of the great arteries (TGA) repaired with full-flow cardiopulmonary bypass. Methods Ten term newborns with TGA undergoing an arterial switch operation were studied with MRI, MRSI, and neurologic examination preoperatively and postoperatively at a median of 5 days (2 to 9 days) and 19 days (14 to 26 days) of age, respectively. Five term historical controls were studied at a median of 4 days (3 to 9 days). Lactate/choline (marker of cerebral oxidative metabolism) and N-acetylaspartate (NAA)/choline (marker of cerebral metabolism and density) were measured bilaterally from the basal ganglia, thalamus, and corticospinal tracts. Results Four TGA newborns had brain injury on the preoperative MRI. The only new lesion detected on the postoperative study was a focal white matter lesion in one newborn with a normal preoperative MRI. The MRSI of age-adjusted lactate/choline was quantitatively higher in newborns with TGA compared with those without heart disease (p < 0.0001), even in newborns without MRI evidence of preoperative brain injury. Lactate/choline decreased after surgery but remained elevated compared with controls. In newborns with TGA, those with preoperative brain injury on MRI had lower NAA/choline globally (p = 0.04) than those with normal preoperative MRI. Five newborns had a decline in NAA/choline from the preoperative to postoperative studies. Conclusions Abnormal brain metabolism and injury was observed preoperatively in newborns with TGA. Brain injury is not solely related to the operative course.
Bibliographical noteFunding Information:
The authors thank Dr George Gregory and the neonatal nurses of the Pediatric Clinical Research Center (PCRC) for their expertise, and gratefully acknowledge the assistance of Mary Ann Bohland and Srivathsa Veeraraghavan in acquiring and processing the MR data. This research is supported by the Larry L. Hillblom Foundation (Start-Up Grant) and the American Heart Association (Beginning Grant-In-Aid 0365018Y; SPM), the Pediatric Clinical Research Center at UCSF (National Institutes of Health RR01271), and National Institutes of Health RO1 NS 40117.