Plain radiographs and thoracic high-resolution CT in patients with ankylosing spondylitis.

OBJECTIVE: The aims of this study were to identify the spectrum of abnormalities seen on high-resolution CT in patients with ankylosing spondylitis and to compare our findings with reports of plain film pulmonary manifestations of the disease.

SUBJECTS AND METHODS: We prospectively studied 26 patients with documented ankylosing spondylitis. All patients underwent plain chest radiography (posteroanterior and lateral views), thoracic helical CT, high-resolution CT, and pulmonary function tests.

RESULTS: High-resolution CT revealed abnormalities in 18 patients (69%), whereas plain chest radiography revealed abnormalities in four patients (15%). The most common abnormalities seen on CT were interstitial lung disease (ILD) (n = 4), bronchial wall thickening and bronchiectasis (n = 6), paraseptal emphysema (n = 3), mediastinal lymphadenopathy (n = 3), tracheal dilatation (n = 2), and apical fibrosis (n = 2).

CONCLUSION: This study, which describes high-resolution CT findings in patients with ankylosing spondylitis, reveals a spectrum of abnormalities unlike those described in previous reports in which researchers used plain chest radiographs as the sole imaging technique. In addition to apical fibrosis, high-resolution CT revealed nonapical ILD, bronchiectasis, paraseptal emphysema, and tracheobronchomegaly. Of these new findings, we believe that identification of ILD is the most important. We suggest that nonapical ILD should be actively sought as an explanation for pulmonary symptoms developing in patients with ankylosing spondylitis. High-resolution CT should form an integral part of such workup.