Lungs of patients with acute respiratory distress syndrome show diffuse inflammation in normally aerated regions: a [18F]-fluoro-2-deoxy-D-glucose PET/CT study.
OBJECTIVE
Neutrophilic inflammation plays a key role in the pathogenesis of acute respiratory distress syndrome (ARDS) and acute lung injury (ALI). Positron emission tomography (PET) with [F]-fluoro-2-deoxy-D-glucose (FDG) can be used to image cellular metabolism that, during lung inflammatory processes, likely reflects neutrophils activity. The aim of this study was to assess the magnitude and regional distribution of inflammatory metabolic activity in the lungs of patients with ALI/ARDS by PET with FDG.


METHODS
Prospective clinical investigation.


METHODS
Ten patients with ALI/ARDS; four spontaneously breathing and two mechanically ventilated subjects, without known lung disease, served as controls.


METHODS
In each individual we performed an FDG PET/computed tomography of the thorax.


RESULTS
FDG cellular influx rate constant (Ki) was computed for the imaged lung field and for regions of interest, grouping voxels with similar density. In all patients with ALI/ARDS, Ki was higher than in controls, also after accounting for the increased lung density. Ki values differed greatly among patients, but in all patients Ki of the normally aerated regions was much higher (2- to 24-fold) than in controls. Whereas in some patients the highest Ki values corresponded to regions with the lowest aeration, in others these regions had lower Ki than normally and mildly hypoaerated regions.


CONCLUSIONS
In patients with ALI/ARDS, undergoing mechanical ventilation since days, the metabolic activity of the lungs is markedly increased across the entire lung density spectrum. The intensity of this activation and its regional distribution, however, vary widely within and between patients.
Bellani
Giacomo
G
Department of Experimental Medicine, 'Centro Bioimmagini Molecolari', University of Milan-Bicocca, Monza (MI), Italy.
Messa
Cristina
C
Guerra
Luca
L
Spagnolli
Ester
E
Foti
Giuseppe
G
Patroniti
Nicolò
N
Fumagalli
Roberto
R
Musch
Guido
G
Fazio
Ferruccio
F
Pesenti
Antonio
A
D055371:Acute Lung Injury / Q000175:diagnosis* / Q000378:metabolism / Q000628:therapy; D000368:Aged; D003422:Critical Care; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D018375:Neutrophil Activation / Q000502:physiology; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000378:metabolism / Q000628:therapy; D012129:Respiratory Function Tests; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18