Computed tomography analysis of airway dimensions and lung density in patients with sarcoidosis.
BACKGROUND
It was previously reported that visual scores of the lung opacities were associated with lung function in patients with sarcoidosis. However, there are no reports on the evaluation of airway dimensions or lung density by computed tomography (CT) in sarcoidosis patients.


OBJECTIVE
The aim of this study was to investigate whether airway dimensions and lung densities assessed by CT associate with pulmonary function in patients with sarcoidosis.


METHODS
CT scanning was performed in 43 sarcoidosis patients and lung densities were measured using in-house software. Means and standard deviations of lung density, kurtosis and skewness of lung density histograms were calculated. Tracheal area and airway wall area/total airway area (WA%) of the right apical bronchus were also measured. Pulmonary function tests were performed on the same day.


RESULTS
Increased standard deviation of lung density and decreased kurtosis and skewness of lung density histograms were all associated with decreased total lung capacity, vital capacity and diffusion capacity. Increased standard deviation of lung density was also associated with decreased percentages of forced expiratory volume in 1 s and peak expiratory flow (%PEF). There was a positive correlation between tracheal area corrected by body surface area and %PEF, and negative correlation between WA% and %PEF. Stepwise regression analysis showed that increased standard deviation of lung density and decreased tracheal area were independently associated with lower %PEF.


CONCLUSIONS
Thus, in sarcoidosis, densitometric parameters reflect restrictive lung function impairment. In addition to parenchymal lesions, it is concluded that the luminal area of the central airways also affects PEF.
Handa
Tomohiro
T
Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan. hanta@kuhp.kyoto-u.ac.jp
Nagai
Sonoko
S
Hirai
Toyohiro
T
Chin
Kazuo
K
Kubo
Takeshi
T
Oga
Toru
T
Niimi
Akio
A
Matsumoto
Hisako
H
Ito
Yutaka
Y
Takahashi
Kenichi
K
Watanabe
Kizuku
K
Izumi
Takateru
T
Mishima
Michiaki
M
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012129:Respiratory Function Tests; D017565:Sarcoidosis, Pulmonary / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D014132:Trachea / Q000000981:diagnostic imaging*