Rheumatoid arthritis-related lung diseases: CT findings.

PURPOSE: To evaluate computed tomographic (CT) findings of rheumatoid arthritis-related lung disease and categorize findings according to pathologic features.

MATERIALS AND METHODS: CT scans obtained in 63 patients (27 men, 36 women; mean age, 61.7 years +/- 11.2 [SD]; range, 28-81 years) with rheumatoid arthritis were assessed. Mean duration of disease was 7.6 years +/- 9.2. Lung parenchymal abnormalities that included airspace consolidation, ground-glass opacity (GGO), reticulation, honeycombing, nodules, bronchiectasis, and air trapping were assessed retrospectively by two chest radiologists. Final decision was reached with consensus of these radiologists and a third radiologist. Patients were classified according to the predominant CT pattern. One of the chest radiologists and a pulmonary pathologist compared CT findings with pathologic findings in 17 patients. Interobserver agreement between the first two radiologists was assessed. Correlation between CT finding extent score and pulmonary function test results was estimated with Spearman rank correlation coefficient.

RESULTS: GGO (57 [90%] patients) and reticulation (62 [98%] patients) were the most common CT features. Four major CT patterns were identified: usual interstitial pneumonia (n = 26), nonspecific interstitial pneumonia (n = 19), bronchiolitis (n = 11), and organizing pneumonia (n = 5). Usual interstitial pneumonia and nonspecific interstitial pneumonia CT patterns overlapped; GGO was more extensive in patients with nonspecific interstitial pneumonia CT pattern (P =.028). In 17 patients who underwent biopsy, CT findings reflected pathologic findings. Exceptions were two patients classified with usual interstitial pneumonia at CT but with nonspecific interstitial pneumonia at pathologic analysis; one patient, with nonspecific interstitial pneumonia at CT but desquamative interstitial pneumonia at pathologic analysis; and one patient, with lymphoid interstitial pneumonia at CT but nonspecific interstitial pneumonia at pathologic analysis.

CONCLUSION: Rheumatoid arthritis is associated with four CT patterns: usual interstitial pneumonia, nonspecific interstitial pneumonia, bronchiolitis, and organizing pneumonia. The most common CT features of rheumatoid arthritis-related lung disease were GGO and reticulation.