Scintigraphic detection of pulmonary aspergillosis in rabbits with a radiolabeled leukotriene b4 antagonist.
Radiolabeled chemotactic peptides have been studied for their applicability to the visualization of infectious and inflammatory foci. Because a radiolabeled leukotriene B4 (LTB4) antagonist allowed visualization of intramuscular E. coli abscesses in rabbits within a few hours after injection, we decided to test the imaging characteristics of this agent in a more clinically relevant model of pulmonary aspergillosis. The pharmacokinetics and imaging characteristics of the 111In-labeled LTB4 antagonist DPC11870 were studied in New Zealand White rabbits with experimental pulmonary aspergillosis infection. The imaging characteristics of 111In-DPC11870 were compared with those of 67Ga-citrate, a radiopharmaceutical commonly used to detect pulmonary infections in patients.


METHODS
Pulmonary aspergillosis was induced in the left lung of rabbits by intratracheal inoculation of 1 x 10(8) conidia of Aspergillus fumigatus. Three days after the inoculation, the rabbits received 111In-DPC11870 or 67Ga-citrate intravenously. Images were acquired at several time points up to 24 h after injection.


RESULTS
Pulmonary aspergillosis was visualized with both agents. Images acquired after injection of 111In-DPC11870 showed uptake in the pulmonary lesions from 6 h after injection. Because of accumulation at the site of infection and clearance from the background, the images improved with time. Region-of-interest analysis at 24 h after injection revealed infected lung-to-normal lung ratios of 5.0 +/- 1.5 for 111In-DPC11870 and 2.9 +/- 0.6 for 67Ga-citrate.


CONCLUSIONS
The radiolabeled LTB4 antagonist DPC11870 clearly delineated experimentally induced pulmonary aspergillosis in rabbits. Images acquired at 24 h after injection of 111In-DPC11870 were superior to those obtained after injection of 67Ga-citrate.
Department of Nuclear Medicine, University Medical Centre Nijmegen, The Netherlands. j.vaneerd@nucmed.umcn.nl
Julliëtte E M
JE
van Eerd
Huub J J M
HJ
Rennen
Wim J G
WJ
Oyen
Thomas D
TD
Harris
D Scott
DS
Edwards
Frans H M
FH
Corstens
Otto C
OC
Boerman
D000818:Animals; D001228:Aspergillosis / Q000000981:diagnostic imaging* / Q000378:metabolism*; D001713:Biphenyl Compounds / Q000493:pharmacokinetics*; D002951:Citrates / Q000493:pharmacokinetics; D005260:Female; D005708:Gallium / Q000493:pharmacokinetics; D007205:Indium Radioisotopes / Q000493:pharmacokinetics; D007975:Leukotriene B4 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008172:Lung Diseases, Fungal / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D009842:Oligopeptides / Q000493:pharmacokinetics*; D009928:Organ Specificity; D011725:Pyridines / Q000493:pharmacokinetics*; D011817:Rabbits; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013777:Tetrazoles / Q000493:pharmacokinetics*; D014018:Tissue Distribution
D001713:Biphenyl Compounds; D002951:Citrates; C476701:DPC11870-11; D007205:Indium Radioisotopes; D009842:Oligopeptides; D011725:Pyridines; D019275:Radiopharmaceuticals; D013777:Tetrazoles; D007975:Leukotriene B4; D005708:Gallium; C103850:gallium citrate