Correlation of HRCT Scoring System with PFT Parameters in Interstitial Lung Disease Associated with Systemic Sclerosis Patients

ABSTRACT

Objectives. Interstitial lung disease (ILD) with features of pulmonary fibrosis and honey-combing is a significant cause of morbidity and mortality in patients with systemic sclerosis (SSc). High resolution computed tomography (HRCT) is the established non-invasive gold standard technique for the diagnosis of SSc related ILD. The present study was designed to characterise HRCT features of ILD in SSc and to correlate pulmonary function test (PFT) parameters with HRCT semi-quantitative scores. Methods. This is an observational, cross-sectional study including 36 patients of SSc who underwent HRCT chest. All the patients were females. Severity and extent were assessed using four HRCT features ground-glass opacity (GGO), mixed GGO and reticular opacity, reticular fibrosis and honey-combing. Thirty-three patients were able to perform PFT. Total HRCT score, inflammatory index and fibrosis index were correlated with PFT parameters. Results. Interstitial lung disease was found in 33 patients (91.6%), 24 patients (66.6%) had mixed GGO along with reticular inter-lobular septal thickening. Majority of the patients (64%) had non-specific interstitial pneumonia (NSIP) pattern. Usual interstitial pneumonia (UIP) pattern was seen in 25% of the cases. One patient had overlapping features of both UIP and organising pneumonia. There was predominant lower lobe involvement. Among the 33 patients who were able to perform PFT, 85% had abnormal results (predicted forced vital capacity [FVC]<80%). Total HRCT score showed significant negative correlation with PFT parameters 枛 FVC (r=�48, P=0.004) and forced expiratory volume in one second (FEV1) (r=�28, P=0.1), respectively. The ratio of FEV1 and FVC had significant positive correlation with total HRCT score (r=0.5, P=0.002). Inflammatory index and fibrosis index had significant negative correlation with predicted FVC% (P<0.05). Conclusions. Mixed pattern (GGO and reticular opacity) was the most common HRCT finding. HRCT semi-quantitative scoring system is sensitive in assessing the severity and extent of ILD qualitatively and quantitatively in SSc patients.