Quantifying pulmonary inflammation in cystic fibrosis with positron emission tomography.
BACKGROUND
Although infection contributes to morbidity in patients with cystic fibrosis (CF), the host inflammatory response is also an important cause of progressive pulmonary function deterioration. Quantifying the inflammatory burden in these patients is challenging and often requires invasive procedures. Positron emission tomographic imaging with [18F]fluorodeoxyglucose ([18FDG]) could be used as a noninvasive alternative to quantify lung inflammation.


OBJECTIVE
To determine the relationships among lung [18F]FDG uptake, bronchoalveolar lavage (BAL) neutrophil concentrations, and pulmonary function in patients with CF.


METHODS
Twenty patients and seven healthy volunteers were studied. A subset of seven patients also consented to undergo BAL. The uptake of [18F]FDG by the lungs was measured as the net influx rate constant Ki. Patients were stratified by rate of decline in pulmonary function into stable, intermediate, and rapidly declining groups. Ki was compared among groups and was correlated against neutrophil concentrations in BAL fluid.


RESULTS
Ki was significantly elevated (p<0.05) among patients with CF as a whole compared with healthy control subjects (0.0015+/-0.0009 versus 0.0007+/-0.0002 ml blood/ml lung/min) but especially in patients with rapidly declining pulmonary function (0.0022+/-0.0011 ml blood/ml lung/min). Ki correlated positively with the number of neutrophils present in BAL fluid.


CONCLUSIONS
Imaging with [18F]fluorodeoxyglucose and positron emission tomography can be used to assess inflammatory burden in patients with CF. Elevations in Ki may be able to identify patients with more aggressive disease and may be useful in monitoring changes in inflammatory burden in response to novel treatments.
Chen
Delphine L
DL
Department of Radiology, Washington University School of Medicine, Campus Box 8223, 660 S. Euclid Ave., St. Louis, MO 63110, USA. chend@mir.wustl.edu
Ferkol
Thomas W
TW
Mintun
Mark A
MA
Pittman
Jessica E
JE
Rosenbluth
Daniel B
DB
Schuster
Daniel P
DP
D000328:Adult; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D003550:Cystic Fibrosis / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007958:Leukocyte Count; D008168:Lung / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009504:Neutrophils / Q000378:metabolism / Q000473:pathology; D011014:Pneumonia / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014018:Tissue Distribution
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18