Imaging lung inflammation in a murine model of Pseudomonas infection: a positron emission tomography study

We tested the hypothesis that the uptake of [18F]fluorodeoxyglucose (FDG), as measured by positron emission tomography (PET) imaging, would correlate with inflammation caused by increasing doses of instilled Pseudomonas aeruginosa (PA) into the lungs of mice. PA-laden agarose beads were instilled via the trachea into 1 lung of each mouse (dose range 0.5-15 x 10(4) CFU) and imaging was performed 3 days later (at the peak of the inflammatory response). Lung uptake of [18F]FDG correlated significantly with the dose of bacteria instilled in mice infected with the M57-15 strain of PA (n = 18) (r2 = .62), but not in mice infected with the PA01 strain (n = 20). The overall lung uptake of [18F]FDG was higher in mice infected with the M57-15 strain than in those infected with the PA01 strain (P < .05). Total white blood cell concentrations in bronchoalveolar lavage were also higher in the M57-15-infected mice. We conclude that PET imaging can detect and quantify differences in host inflammatory response to 2 different strains of PA. The combination of PET imaging with murine models should be a useful new tool to study neutrophil trafficking and kinetics in lung inflammation.