Comparison of deposition images obtained by use of an ultrafine 99m-technetium-labeled carbon dry aerosol with ventilation images obtained by use of 81m-krypton gas for evaluation of pulmonary dysfunction in calves.
OBJECTIVE
To characterize the accuracy of an ultrafine 99m-technetium-labeled carbon dry aerosol for use in assessment of regional ventilation in calves with pulmonary dysfunction.


METHODS
7 Belgian White and Blue calves.


METHODS
The ultrafine aerosol was assessed by comparing deposition (D) images with ventilation (V) images obtained by use of 81 m-krypton (81mKr) gas via D-to-V ratio (D:V) image analysis in calves during spontaneous breathing (SB) and during experimentally induced pulmonary dysfunction (ePD).


RESULTS
Mismatching index (LrTot) calculated on the D:V images revealed a good match (LrTot, 0.96 +/- 0.01) between D and V distribution patterns in calves during SB. Calculation of the ultrafine aerosol penetration index relative to 81mKr (PIRel) revealed preferential distribution of the ultrafine aerosol in lung parenchyma (PIRel, 1.13 +/- 0.11). In ePD, heterogeneity in the D:V distribution was observed (LrTot, 0.78 +/- 0.10) as a result of ultrafine aerosol particles impaction in airways as indicated by PIRel (0.66 +/- 0.16) and a proportion of pixels more radioactive in D images, compared with V images, that was located in the central part of the lung (475 +/- 77% in ePD vs 32.8 +/- 5.7% in SB). However, this central deposition did not prevent visual examination of the entire ventilated lung.


CONCLUSIONS
The ultrafine aerosol appears suitable for use in examination of ventilated parts of lungs of cattle, even those with impaired pulmonary function. However, airway impaction of ultrafine aerosol particles impedes the quantification of regional ventilation in cattle with abnormal lung function.
Votion
D M
DM
Department of Physiology, Faculty of Veterinary Medicine, University of Liège, Belgium.
Coghe
J D
JD
Lekeux
P M
PM
D000336:Aerosols; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D007091:Image Processing, Computer-Assisted; D007727:Krypton Radioisotopes; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary*; D011877:Radionuclide Imaging / Q000662:veterinary; D012129:Respiratory Function Tests / Q000379:methods / Q000662:veterinary*; D013670:Sodium Pertechnetate Tc 99m; D018709:Statistics, Nonparametric
D000336:Aerosols; D007727:Krypton Radioisotopes; D013670:Sodium Pertechnetate Tc 99m