Early pulmonary involvement in ankylosing spondylitis: assessment with thin-section CT.
OBJECTIVE
To determine the frequency and the distribution of early pulmonary lesions in patients with ankylosing spondylitis (AS) and a normal chest X-ray on thin-section CT and to correlate the CT findings with the results of pulmonary function tests and clinical data.


METHODS
Twenty-five patients with clinically proven AS and no history of smoking underwent clinical examinations, pulmonary function tests (PFT), chest radiography, and thin-section CT. Four of 25 patients (16%), who had obvious signs on plain films suggestive of pre-existing disorders unrelated to AS were excluded.


RESULTS
Fifteen of 21 patients (71%) had abnormalities on thin-section CT. The most frequent abnormalities were thickening of the interlobular septa in seven of 21 patients (33%), mild bronchial wall thickening in (6/21, 29%), pleural thickening and pleuropulmonary irregularities (both 29%) and linear septal thickening (6/21, 29%). In six patients there were no signs of pleuropulmonary involvement. Eight of 15 patients (53%) with abnormal and four of six patients (67%) with normal CT findings revealed mild restrictive lung function impairment.


CONCLUSIONS
Patients with AS but a normal chest radiograph frequently have abnormalities on thin-section CT. As these abnormalities are usually subtle and their extent does not correlate with functional and clinical data, the overall routine impact of thin-section CT in the diagnosis of AS is limited.
Turetschek
K
K
Department of Radiology, University of Vienna, Austria. Karl.Turetschek@univie.ac.at
Ebner
W
W
Fleischmann
D
D
Wunderbaldinger
P
P
Erlacher
L
L
Zontsich
T
T
Bankier
A A
AA
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*