[Relationship between flow volume curve and CT findings in non-smoking patients with long histories of bronchial asthma].
OBJECTIVE
This study was conducted to verify whether bronchial asthma (BA) alone causes pulmonary emphysema (PE), and to examine the computed tomography (CT) findings in non-smokers with BA demonstrating the flow volume curve (FV curve) characteristic of PE.


METHODS
Non-smoking patients with a history of BA for more than 20 years were divided into 2 groups: the dogleg pattern group (n = 5), with an FV curve characteristic of PE, and the concave pattern group (n = 16) with an FV curve characteristic of BA. CT scans was performed using CT values (level, 900 H.U.; width, 400 H.U.) that facilitate detection of a low attenuation area (LAA), and using conventional CT values (level, 700 H.U.; width, 1,300 H.U.). LAA (including air trapping), thickness of the bronchial wall, and partial atelectasis were compared between the 2 groups.


RESULTS
PE was not detected, although air trapping was found in all subjects. The thickness of the airway was greater in the dogleg pattern than in the concave pattern. The incidences of air trapping and partial atelectasis were higher in the former than in the latter.


CONCLUSIONS
BA alone may not cause PE. Some BA patients without PE show the FV curve characteristic of PE, reflecting an increase in the thickness of the airway wall and a decrease in the pulmonary ventilation probably due to the air trapping and the partial atelectasis.
Kawamoto
H
H
Department of Clinical Laboratory Medicine, Faculty of Medicine, Hiroshima University.
Kambe
M
M
Yamagata
M
M
Nakajima
H
H
Yamane
K
K
Kuraoka
T
T
Miyamura
I
I
D000368:Aged; D001249:Asthma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008449:Maximal Expiratory Flow-Volume Curves; D008875:Middle Aged; D013997:Time Factors; D014057:Tomography, X-Ray Computed