Modeling pulmonary kinetics of 2-deoxy-2-[18F]fluoro-D-glucose during acute lung injury.
OBJECTIVE
Dynamic positron emission tomographic imaging of the radiotracer 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) is increasingly used to assess metabolic activity of lung inflammatory cells. To analyze the kinetics of (18)F-FDG in brain and tumor tissues, the Sokoloff model has been typically used. In the lungs, however, a high blood-to-parenchymal volume ratio and (18)F-FDG distribution in edematous injured tissue could require a modified model to properly describe (18)F-FDG kinetics.


METHODS
We developed and validated a new model of lung (18)F-FDG kinetics that includes an extravascular/noncellular compartment in addition to blood and (18)F-FDG precursor pools for phosphorylation. Parameters obtained from this model were compared with those obtained using the Sokoloff model. We analyzed dynamic PET data from 15 sheep with smoke or ventilator-induced lung injury.


RESULTS
In the majority of injured lungs, the new model provided better fit to the data than the Sokoloff model. Rate of pulmonary (18)F-FDG net uptake and distribution volume in the precursor pool for phosphorylation correlated between the two models (R(2)=0.98, 0.78), but were overestimated with the Sokoloff model by 17% (P< .05) and 16% (P< .0005) compared to the new one. The range of the extravascular/noncellular (18)F-FDG distribution volumes was up to 13% and 49% of lung tissue volume in smoke- and ventilator-induced lung injury, respectively.


CONCLUSIONS
The lung-specific model predicted (18)F-FDG kinetics during acute lung injury more accurately than the Sokoloff model and may provide new insights in the pathophysiology of lung injury.
Schroeder
Tobias
T
Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, 55 Fruit St., Boston, MA 02114, USA. tobias.schroeder@vqpet.mgh.harvard.edu
Vidal Melo
Marcos F
MF
Musch
Guido
G
Harris
R Scott
RS
Venegas
Jose G
JG
Winkler
Tilo
T
D000704:Analysis of Variance; D000818:Animals; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D008954:Models, Biological; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging*; D012756:Sheep
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18