TY - JOUR
T1 - FDG-PET imaging of pulmonary inflammation in healthy volunteers after airway instillation of endotoxin
AU - Chen, Delphine L.
AU - Rosenbluth, Daniel B.
AU - Mintun, Mark A.
AU - Schuster, Daniel P.
PY - 2006/5
Y1 - 2006/5
N2 - Recent studies indicate that a focal, limited, inflammatory response can be safely elicited after direct bronchial instillation of small doses of endotoxin into a single lung segment. Because the radiotracer [18F] fluorodeoxyglucose ([18F]FDG) is taken up at accelerated rates within inflamed tissues, we hypothesized that we could detect and quantify this regional inflammatory response with positron emission tomography (PET). We imaged 18 normal volunteers in a dose-escalation study with 3 endotoxin dosing groups (n = 6 in each group): 1 ng/kg, 2 ng/kg, and 4 ng/kg. Endotoxin was instilled by bronchoscopy into a segment of the right middle lobe, with imaging performed ∼24 h later, followed by bronchoalveolar lavage (BAL). A "subtraction imaging analysis" was performed in the highest dose cohort to identify the area of inflammation, using the preendotoxin scan as a baseline. BAL neutrophil counts were significantly higher in the highest dose group compared with the other two groups (1,413 ± 625 vs. 511 ± 396 and 395 ± 400 cells/mm3; P < 0.05). Autoradiography performed on cells harvested by BAL showed specific [3H]deoxyglucose ([3H]DG) uptake limited to neutrophils. In vitro [3H]DG uptake in BAL neutrophils in the 4 ng/kg dose group (but not in the 2 ng/kg group) was statistically greater than in peripheral blood neutrophils obtained before endotoxin instillation. The rate of [18F]FDG uptake was greatest in the 4 ng/kg group, with a consistent, statistically significant increase in the rate of uptake after endotoxin instillation compared with baseline. We conclude that the inflammatory response to low-dose endotoxin in a single lung segment can be visualized and quantified by imaging with FDG-PET.
AB - Recent studies indicate that a focal, limited, inflammatory response can be safely elicited after direct bronchial instillation of small doses of endotoxin into a single lung segment. Because the radiotracer [18F] fluorodeoxyglucose ([18F]FDG) is taken up at accelerated rates within inflamed tissues, we hypothesized that we could detect and quantify this regional inflammatory response with positron emission tomography (PET). We imaged 18 normal volunteers in a dose-escalation study with 3 endotoxin dosing groups (n = 6 in each group): 1 ng/kg, 2 ng/kg, and 4 ng/kg. Endotoxin was instilled by bronchoscopy into a segment of the right middle lobe, with imaging performed ∼24 h later, followed by bronchoalveolar lavage (BAL). A "subtraction imaging analysis" was performed in the highest dose cohort to identify the area of inflammation, using the preendotoxin scan as a baseline. BAL neutrophil counts were significantly higher in the highest dose group compared with the other two groups (1,413 ± 625 vs. 511 ± 396 and 395 ± 400 cells/mm3; P < 0.05). Autoradiography performed on cells harvested by BAL showed specific [3H]deoxyglucose ([3H]DG) uptake limited to neutrophils. In vitro [3H]DG uptake in BAL neutrophils in the 4 ng/kg dose group (but not in the 2 ng/kg group) was statistically greater than in peripheral blood neutrophils obtained before endotoxin instillation. The rate of [18F]FDG uptake was greatest in the 4 ng/kg group, with a consistent, statistically significant increase in the rate of uptake after endotoxin instillation compared with baseline. We conclude that the inflammatory response to low-dose endotoxin in a single lung segment can be visualized and quantified by imaging with FDG-PET.
KW - Cystic fibrosis
KW - Fluorodeoxyglucose
KW - Neutrophils
KW - Positron emission tomography
UR - http://www.scopus.com/inward/record.url?scp=33646422719&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.01429.2005
DO - 10.1152/japplphysiol.01429.2005
M3 - Article
C2 - 16424067
AN - SCOPUS:33646422719
SN - 8750-7587
VL - 100
SP - 1602
EP - 1609
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 5
ER -