Influence of hilar deposition in the evaluation of the alveolar epithelial permeability on 99mTc-DTPA aerosol inhaled scintigraphy.
OBJECTIVE
We investigated whether hilar radioaerosol deposition affects the clearance rate of technetium-99m-labeled diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) from peripheral alveolar regions.


METHODS
A total of 38 patients underwent (99m)Tc-DTPA inhalation lung scintigraphy. Six region of interest (ROI) patterns were adopted: ROI 1 was outlined around the entire hemithorax, and ROIs 2-6 were outlined around the hemithorax but excluded square ROIs of different size in the hilar region. Half-times (T(1/2) were calculated with time-activity curves using one-compartment and two-compartment analyses. The T(1/2) of ROIs 1-5 were plotted against the T(1/2) of ROI 6, and regression lines were obtained with the least-squares method. The absolute values of the differences between surveyed values and regression line were calculated. The Wilcoxon test for trend and a single linear regression model were used to determine statistical significance.


RESULTS
There were significant reductions in the absolute values of the differences between surveyed values and regression line from ROIs 1-5 by one-component analysis and the fast component of two-compartment analysis (P < 0.001).


CONCLUSIONS
Our results suggest that the deposition of radioaerosol in the hilar region affects the clearance rate of (99m)Tc-DTPA from the alveoli in damaged lungs. The hilar region should be excluded from ROIs when alveolar epithelial permeability is evaluated.
Department of Radiology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan. ogis@jikei.ac.jp
Shigeyuki
S
Ogi
Eisuke
E
Gotoh
Mayuki
M
Uchiyama
Kunihiko
K
Fukuda
Mitsuyoshi
M
Urashima
Nobuyoshi
N
Fukumitsu
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000336:Aerosols; D000368:Aged; D000369:Aged, 80 and over; D001980:Bronchi / Q000000981:diagnostic imaging*; D002648:Child; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010539:Permeability; D011650:Pulmonary Alveoli / Q000000981:diagnostic imaging* / Q000378:metabolism; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D020545:Respiratory Mucosa / Q000378:metabolism; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics*; D013909:Thorax / Q000000981:diagnostic imaging*; D055815:Young Adult
D000336:Aerosols; D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate