[F-18] FLUORODEOXYGLUCOSE UPTAKE IN NEONATAL ACUTE LUNG INJURY MEASURED BY POSITRON EMISSION TOMOGRAPHY

The objective of this study was to evaluate positron emission tomograp hy (PET) of [F-18]fluorodexoyglucose ((18)FDG) uptake as a measure of neonatal acute lung injury. Inasmuch as intrapulmonary sequestration o f neutrophils is a hallmark of acute lung injury, quantification of ne utrophil activity using (18)FDG may offer a novel, in vivo technique t o examine the progression and resolution of this disease. Ten newborn piglets were studied; six received bronchoalveolar lavage followed by 4 h of high pressure ventilation to create acute lung injury. Four hea lthy piglets served as controls. (18)FDG (0.8 mCi/kg; 29.6 MBq) was gi ven i.v. and PET (ECAT 953/31, Siemens) was performed for 90 min. Duri ng PET, all animals were sedated, paralyzed, and ventilated to maintai n normal blood gases. The time course of radioactivity in lung regions and in plasma was used to calculate the rate constant for the metabol ic trapping of (18)FDG in tissue according to the method of C. S. Patl ak. Median (18)FDG influx constants were significantly higher in injur ed piglets (0.0187 min(-1)) than in control piglets (0.0052 min(-1)) ( p < 0.01). Moreover, consistent with the (18)FDG uptake data, injured piglets had moderate to severe injury on lung histology whereas contro l piglets had only slight and focal histologic changes. We conclude th at PET of (18)FDG uptake is an accurate, readily repeatable in vivo me asure of neonatal acute lung injury.