Dynamic FDG PET for assessing early effects of cerebral  hypoxia and resuscitation in new-born pigs.
OBJECTIVE
Changes in cerebral glucose metabolism may be an early prognostic indicator of perinatal hypoxic-ischaemic injury. In this study dynamic ¹⁸F-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 (FiO₂) 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 (CMRgl) 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 CMRgl but no significant differences in global or regional CMRgl between the resuscitation groups were found.


CONCLUSIONS
Dynamic FDG PET detected decreased cerebral glucose metabolism early after perinatal hypoxia in piglets. The decrease in CMRgl 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.
Department of Paediatric Research, Oslo University Hospital, Rikshospitalet, PO Box 4950, Nydalen, 0424 Oslo, Norway. charlotte.de.lange@rr-research.no
Charlotte
C
de Lange
Eirik
E
Malinen
Hong
H
Qu
Kjersti
K
Johnsrud
Arne
A
Skretting
Ola Didrik
OD
Saugstad
Berit H
BH
Munkeby
D000388:Air; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D002534:Hypoxia, Brain / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D010100:Oxygen / Q000627:therapeutic use; D049268:Positron-Emission Tomography; D013552:Swine; D013997:Time Factors
D019788:Fluorodeoxyglucose F18; D005947:Glucose; D010100:Oxygen