Interstitial lung disease in systemic sclerosis: An HRCT-clinical correlative study

Purpose: To evaluate high-resolution CT (HRCT) parameters of inflammation and fibrosis in systemic sclerosis (SSc), for correlation with lung function, skin scores and exercise tolerance. Material and Methods: 45 SSc patients (40 women, 48.5±13.4 years), underwent thoracic HRCT, lung function assessment, and modified Rodnan skin scores. Exercise tolerance was also graded. HRCT were scored for extent of 4 HRCT patterns of interstitial lung disease (ILD): ground glass opacification (GGO), reticular, mixed and honeycomb pattern in each lobe. Total HRCT score, inflammation index (GGO and mixed score) and fibrosis index (reticular and honeycomb scores) were correlated with lung function and clinical parameters. Results: ILD was present in 39/45 (86.7%) patients. Abnormal (<80% predicted) forced vital capacity (FVC), total lung capacity (TLC) and carbon monoxide diffusion factor (DLco) were detected in 30%, 22% and 46% of patients. Total HRCT score correlated with FVC (r=−0.43, p=0.008), FEV1 (forced expiratory volume) (r=–0.37, p=0.03), TLC (r=–0.47, p=0.003), and DLCO (r=–0.43, p=0.008); inflammatory index with DLCO (r=–0.43, p=0.008) and exercise tolerance (r=–0.39, p < 0.05); and fibrosis index with FVC (r=–0.31, p=0.05) and TLC (r=–0.38, p=0.02). Higher total HRCT score, and inflammation and fibrosis indices were found in patients with abnormal lung function. Conclusion: Qualitative HRCT is able to evaluate inflammation and fibrosis, showing important relationships with diffusion capacity and lung volume, respectively.