| Objective: The aim of this study was to assess the main abnormal finding in patients with rheumatoid arthritis (RA) associated with pulmonary involvement detected by HRCT, to discuss the potential relationships between abnormal HRCT finding and clinical characteristics, and to evaluate the type and occurrence rate of lung abnormalities detected by HRCT in RA patients with or without pulmonary symptoms, or between smoker or nonsmokers, then to observe the curative effect treated with disease-modifying antirheumatic drugs by HRCT, which may provide imaging data for monitoring therapeutic effect of pulmonary involvement in rheumatoid arthritis in the clinical settingMethods: From February 2009 to February 2010, 98 consecutive patients with rheumatoid arthritis in affiliated hospital of north Sichuan medical college, who met the inclusion criteria, were enrolled into our study. Patients were excluded from this study if they associated with another pulmonary disease, such as infection, tuberculosis, chronic obstructive lung disease, bronchial asthma, cor pulmonale, drug toxicity or lung tumor, if they associated with another connective tissue disease proven by clinical or laboratory examination, if they had interstitial lung disease caused by pneumonoconiosis, anaphylaxis, inhalation of organics or tumor-relative radiotherapy, and if they had chronic cardiac insufficiency, pulmonary function defect and renal inadequacy. All patients had venous blood taken for full blood count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), renal and liver function, uric acid (UA) and plasma proteins. Immunological investigations included IgM rheumatoid factor (IgM-RF), antinuclear antibodies (ANA), and anticyclic citrullinated peptide antibody, (anti-CCP antibody). All patients underwent chest radiography (CRX) and thoracic HRCT scanning. The main CRX and HRCT findings in each patient were subsequently analyzed, and the correlation between HRCT abnormalities finding with clinical data, serum laboratory index, and status of antirheumatic drugs were evaluated. Meanwhile, the degree of lung affection was assessed on a 5-point scale on HRCT, and the correlation between HRCT score of lung involvement with disease duration, age and pack-year were assessed, and the HRCT score of lung involvement between patients with or without pulmonary symptoms, and between smokers or nonsmokers were compared. In patients who underwent follow-up examination, the HRCT finding of pre-and-post treatment were compared.Result:Chest imaging findings: Plain chest radiographs were normal in 61 (62.45%) patients and showed interstitial disease in 11 (11.22%) patients, pleural abnormalities in 3 (3.1%) patients. HRCT findings were abnormal in 56 (57.14%) patients. reticulation and septal thickening was the most common abnormalities, which observed in 43 (43.88%) and 43(43.88%)cases, respectively. Ground-glass densities, bronchiectasis, honeycomb pattern, subpleural or pulmonary micronodular and nodular densities was seen in 22, 29, 17, 16 cases, respectively. The enlargement of pulmonary artery diameter was seen in 2 (2%) cases. The interstitial abnormalities usually with basal and subpleural lung regions distribution, and nodular density, emphysema and bronchiectasis were predominantly involved whole lung. Relationship between clinical data and high-resolution computed tomography findings: By bivariate analysis, abnormal HRCT findings were significantly correlated with age older than 50 years, positive tests for IgM rheumatoid factors and anticyclic citrullinated peptide antibody. Neither was current second line treatment of any kind significantly associated with abnormal HRCT findings. Evaluation by the Kruskal-Wallis test found no significant associations linking RA duration to HRCT abnormalities (P=0.558). The degree of lung involvement was correlated with age (r=0.683, p<0.0001), but not correlated with disease duration (r=0.196, P=0.053). However, reticular patterns were found to predominate in patients with long-lasting disease, whereas a predominance of ground glass patterns was found more frequently in patients with a shorter course of disease (9.05±7.43 vs. 5.3±2.21, P=0.019).Comparison of pulmonary involvement between smokers and nonsmokers: The average tobacco smoke exposition to smokers was 9.16±7.06 PY,and HRCT findings were abnormal in 31 (57.41%) patients. The most frequent abnormalities were emphysema (57.41%), reticulation (40.70%) and bronchiectasis (38.89%). HRCT findings were abnormal in 25 non-smoke RA patients, with the most common abnormalities by HRCT were interlobular septal thickening (24/44, 54.55%) and reticulation (21/44, 47.27%). The occurrence rate of emphysema and bronchiectasis detected by HRCT were significantly higher in smokers. The HRCT score of lung involvement was higher in smokers; however, this result has no statistical significance (2.84±1.04 vs.2.52±1.00, P=0.251). The HRCT score of lung involvement was not correlated with cigarette consumption in pack years (r=0.215, P=0.122). Comparison of pulmonary involvement between patients with or without pulmonary symptoms: In 23 patients with pulmonary symptoms, HRCT findings were abnormal in 16 patients; with the most common abnormalities were interlobular septal thickening (69.56%), reticulation (60.87%) and ground-glass densities (39.13%). In 21 patients without pulmonary symptom, HRCT were abnormal in 9 cases, interlobular septal thickening (42.86%) and reticulation (33.33%) was the most frequent abnormalities. The occurrence rate of bronchiectasis and honeycomb pattern was higher in patients with respiratory symptom. The HRCT score of lung involvement in patients with respiratory symptom was significantly higher than that in patients without respiratory symptom (3.0±0.85 vs.1.8±0.70,P= 0.002). Study of follow-up examinations: Fourteen patients underwent follow-up examinations, after antirheumatic and anti-inflammatory treatment, the lesion extent in 5 patients with predominance of ground glass patterns found to be decreased, and in another 9 patients, however, the range of lesion were increased (n=3) or constant (n=6) and disease was considered stable.Conclusion:1. This study confirms the value of HRCT for the detection of the variable and discontinuously distributed pulmonary lesions in RA associated with lung involvement. Interstitial lung disease and airway disease is the most common finding, predominantly involve basal and subpleural lung regions.2. Lung involvement is correlated with age and rheumatoid arthritis severity. Smoking patients often associated with air way involved. Severity pulmonary involvement often occurred in elder patients and patients with pulmonary symptom, which indicated advanced interstitial fibrosis. HRCT scanning detects lung involvement at a much earlier stage, before significant pulmonary compliance.3. GGOs frequently (but not always) occurred in patients with shorter disease duration, indicated early disease activity and represent lung parenchyma alterations that are potentially reversible under therapy. |
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