Dynamic FDG PET for assessing early effects of cerebral hypoxia and resuscitation in new-born pigs

Purpose Changes in cerebral glucose metabolism may be an early prognostic indicator of perinatal hypoxic–ischaemic injury. In this study dynamic 18 F-FDG PET was used to evaluate cerebral glucose metabolism in piglets after global perinatal hypoxia and the impact of the resuscitation strategy using room air or hyperoxia. Methods New-born piglets ( n = 16) underwent 60 min of global hypoxia followed by 30 min of resuscitation with a fraction of inspired oxygen (FiO 2 ) of 0.21 or 1.0. Dynamic FDG PET, using a microPET system, was performed at baseline and repeated at the end of resuscitation under stabilized haemodynamic conditions. MRI at 3 T was performed for anatomic correlation. Global and regional cerebral metabolic rates of glucose (CMR gl ) were assessed by Patlak analysis for the two time-points and resuscitation groups. Results Global hypoxia was found to cause an immediate decrease in cerebral glucose metabolism from a baseline level (mean ± SD) of 21.2 ± 7.9 to 12.6 ± 4.7 μmol/min/100 g ( p <0.01). The basal ganglia, cerebellum and cortex showed the greatest decrease in CMR gl but no significant differences in global or regional CMR gl between the resuscitation groups were found. Conclusion Dynamic FDG PET detected decreased cerebral glucose metabolism early after perinatal hypoxia in piglets. The decrease in CMR gl may indicate early changes of mild cerebral hypoxia–ischaemia. No significant effect of hyperoxic resuscitation on the degree of hypometabolism was found in this early phase after hypoxia. Cerebral FDG PET can provide new insights into mechanisms of perinatal hypoxic–ischaemic injury where early detection plays an important role in instituting therapy.