Evaluation of Cerebral Metabolism for Children Undergoing Open Heart Surgery for Atrial Septal Defect Using Proton Magnetic Resonance Spectroscopy

Abstract

Background and Objectives The purpose of this study was to investigate whether a brief cardiopulmonary by-pass, with mild hypothermia and normal flow, would have any deleterious effects on brain metabolism in children. This is the first study using localized in vivo proton magnetic resonance spectroscopy 1H-MRS in brains of children with ASD undergoing open-heart surgery OHS . Subjects and Methods Seven children undergoing surgical closure of ASD, with mild hypothermia and normal flow cardiopulmonary by-pass, were studied. Their ages ranged from 18 to 47 months, and body weights ranged from 11 to 17 kg. We performed 1H-MRS before OHS, and 1 3 months after, then compared the values of brain metabolite ratios before and after surgery. The values from our patients were compared to those from 12, age-matched, normal children. All MR imaging, and localized 1H-MRS, were performed using a GE 1.5T SIGNA system General Electric Medical System, Milwaukee, USA . Image guided STEAM-spectra were obtained from, the parietal white matter PWM , and occipital gray matter OGM , with TE of 30 msec, and TR of 3 sec, using a PROton Brain Exam PROBE General Electric Medical System, Milwaukee, USA . Results All metabolite ratios, measured by 1H-MRS, from patients before surgery showed no significantly difference from postoperative values. However, choline/creatine ratios, obtained from PWM, were higher in both pre-and postoperative ASD patients, as compared to those of normal children. Conclusion We concluded, that brain metabolism, measured by 1H-MRS, does not change significantly after OHS, for children with ASD, with mild hypothermia and normal flow. Korean Circulation J 2002 ; 32 2 : 155-162